Are ATC assigned altitudes temperature compensated?

Answering for the US. Controllers in the US do not assign altitudes differently based on temperature.
From the AIM:

5−1−17. Cold Temperature Operations Pilots should begin planning for
operating into airports with cold temperatures during the preflight
planning phase. Instrument approach charts will contain a snowflake
symbol and a temperature when cold temperature correction must be
applied. Pilots operating into airports requiring cold temperature
corrections should request the lowest forecast temperature at the
airport for departure and arrival times. If the temperature is
forecast to be at or below any published cold temperature restriction,
calculate an altitude correction for the appropriate segment(s) and/or
review procedures for operating automatic cold temperature
compensating systems, as applicable. The pilot is responsible to
calculate and apply the corrections to the affected segment(s) when
the actual reported temperature is at or below any published cold
temperature restriction, or pilots with automatic cold temperature
compensating systems must ensure the system is on and operating on
each designated segment. Advise ATC when intending to apply cold
temperature correction and of the amount of correction required on
initial contact (or as soon as possible) for the intermediate segment
and/or the published missed approach. This information is required for
ATC to provide aircraft appropriate vertical separation between known
traffic.

All pilots in the same general area of airspace are issued a common altimeter setting, which ensures everyone is on the same reference point of pressure as it relates to the weather, but not the temperature, specifically. ATC separates using altitude or lateral primarily and has a separation standard for this reason, so that if someone is off by a few hundred feet, it doesn't cause a collision due to being off as a result of atmospheric conditions. If nobody is correcting their altitude and basing it off ATC assignments and a common altimeter, there really shouldn't be much deviation.
Source: former ATC'er.


What are the characteristics of the F-16 airframe lifetime?

It is difficult to estimate how long a particular airframe might last. Also, different aircraft might last different amounts of time for esoteric reasons. For example, mercury amalgamates with aluminum and can weaken it. Even a small amount of mercury can significantly weaken an aluminum structural member. Therefore, you might have one plane with some mercury contamination that will not last nearly as long as one free from that accidental contamination.

Also, how the aircraft is used will significantly affect its lifetime. A few high-stress maneuvers can weaken an airframe. Conversely, an aircraft that is babied and lightly driven may last for many decades.

Ultimately, there is no way to predict how long a given aircraft will last. The best thing to do is to observe it and when cracks start to appear, then you know there is a problem.

To compensate for fatigued structural members, it may be possible, but it depends entirely on the scope and nature of the fatigue. If the fatigue is limited to a restricted location, then theoretically that area could be reinforced. The problem is that the complexity of the engineering is such that in most cases it will be cheaper and more effective to simply replace the aircraft.

Usually wear is most severe at the wing roots, so a plane that is experiencing fatigue can potentially be improved by replacing the wings, but the cost of this is pretty significant, so normally you would only see this in an air force that could not buy new aircraft for some reason.


What is this red dashed line between door and cockpit window?

(Source: airliners.net)

The letters read 'air bridge'. The line is used for docking with the air bridge as you suspected. Also see: What are these markings under the passenger door?

  (...) the position of the alignment marks are not standardized and are carrier specific.

It also appears on the silver livery:

(Source: planespotters.net)

It reminds me of this:

(Source: wikimedia.org)


What is CAS and EAS and how to calculate from IAS?

If you don´t mind, I´ll keep it in simple terms.

We start off with IAS - that´s the airspeed you see on your instruments. You have static port - registering pressure around your aircraft, pitot tube, registering how many molecules of air getting inside. And by subtracting one from another, you get your IAS.
Dummy example: Static registers 100 molecules around. Pitot registers 200 molecules, which would equal to speed of 100kts.

CAS - it the speed corrected for instrument error. Because no instruments are perfect.
Again, just one example, since a/c is moving through the air, pushing the air aside, it does create lower pressure around the a/c. Which in term, does affect reading of static and pitot tubes (registering wrong amount of molecules).
As a pilot, CAS is less relevant speed, as it will be used mostly for certification process.

CAS - EAS is made by allowing for compressibility effects. At very high altitude and very high speeds (jet fighters/bombers/space shuttle), there are different rules in action.

There is another speed, TAS. If you want to do everything perfect, first you need to convert IAS to CAS, (by using special table for a given airplane) and then convert CAS to TAS.
TAS is your real airspeed, moving through the air. It might differ greatly from IAS depending on pressure and temperature. In standard (ISA) conditions CAS will be equal to TAS.
But what happens when you fly at an altitude of 40.000 feet? Well, air is a lot less dense. For a given cube of air, there are a lot less molecules.
In order to fly and not to stall, you must see "100kts IAS" on your airspeed indicator. Ssince there are so fewer molecules in the air, your real airspeed through the air must be 2-3 times higher, in order to hit all those 100 molecules. Does it make sense?

As a pilot, greatest importance for you is IAS. It shows you how many molecules of air you are hitting (dynamic pressure). Stall speed, never exceed - all based on IAS. Your TAS can be whatever, but IAS is the one affects your airplane.

So why do we care about TAS? Well, based on TAS and wind, we can derive our GS - ground speed. And GS is important! It will tell you, how long time will it take for you to get from A to B. Based on time, you know how much fuel you will need. Perhaps, you would need to make an extra refuelling stop on your way. Or you calculate and see that airport will be closed by the time you arrive there?
Later on, as an airline pilot, you know if you are early/late, duty times, etc, etc.

There is Mach number as well, but since you didn´t ask, I´ll just say you will need it flying at higher altitudes (approx. above 25,000 feet) and at those altitudes, it will take over IAS.


Low-wing taildraggers pictured on 2021 ASA FAR/AIM cover?

They are Jodels. All wood.  The D-11 was a very popular homebuilt once upon a time (a friend owns one), along with factory production of various models in France in the '60s.  Hard to say exactly which models those are.


Are there any legal requirements concerning airline pilots and their watches?

Well, a wristwatch can't be used to sneak around the requirement that IFR requires a clock mounted in the aircraft, FAR 91.205(d)(6).  A missing or inoperative clock isn't likely in a modern airliner.  As far as the FAA is concerned, a wristwatch is nothing more than jewelry.

Ages ago, a wristwatch may have helped with calculating fuel burn and range, but even then, it was a convenience rather than mandated equipment.


How much does a passenger-to-freighter conversion cost?

Companies converted 87 passenger jets in 2018 ... Direct conversion costs for the 87 aircraft totaled \$641.5 million ... The direct cost of converting a Boeing 767-300ER amounts to some \$14 million, compared with \$15 million for an A330-200 and \$16 million for an A330-300 ...

Source: Freighter Conversion Market Totaled Nearly \$1B in 2018: IBA, ainonline.com

2018's average is 7–8 million USD per conversion.

Based on this source, an A330-300's heavy (D) check costs 3.8 million USD (adjusted for inflation from 2010 to 2018), and given the quoted conversion for the A333, it's ~4 times as much to do the conversion.

  Source: Boeing 747-400 Passengers to Cargo Conversion, Israel Aerospace Industries, YouTube

Of the changes:

The fuselage is cut and reinforced to allow for the bigger door
The floor may require reinforcement
Passenger environmental control systems are removed
Cargo fire suppression is installed
A 9G crash net is installed.

More in this A330-300/-200 P2F brochure (PDF). And then there is certification.


How does ATC locate a stealth aircraft if its transponder fails?

It depends on the aircraft.  One example was on the F-117, which had removable radar reflectors on the sides of the aircraft, allowing the jet to be detected by primary and secondary ATC radars.

As to more modern stealth aircraft, it’s possible they use similar systems to ensure ATC tracking in peacetime.


Has any accident been prevented by bending or breaking the rules?

First I have to admit that I have no idea what FAA regulations said about passengers taking part in controlling an airplane in 1989, but I guess it was at least frowned upon, even if the passenger happened to be a pilot.

The United Airlines flight 232 made a stunningly successful "landing" at Sioux City airport, much due to the fact that they took an extra crew member from the cabin to control the throttles of their severely disabled aircraft.

Unfortunately 112 people lost their lives as the plane cartwheeled after a very rough touchdown, and one might ask what is so successful about that... well: 184 people survived a situation that was in subsequent simulations deemed to be impossible to manage.

The throttle operator was a UA training check airman Dennis Edward Fitch, riding as a passenger on this ill-fated flight. It has been stated in many sources again and again, that without his presence in the cockpit, the outcome would have been much worse, even the worst possible.

It just so happened, that Fitch had been practicing a similar scenario in a simulator after a fatal crash of Japan Airlines flight 123 in 1985. The reason of that crash was total loss of hydraulics, Fitch wanted to find out if an airliner could be controlled with throttles only. Luckily, it was somewhat possible.


Is an ADS-B IN able to receive signal from ADS-B OUT of the same aircraft?

On small aircraft many operators use portable ADS-B IN receivers which typically do not have the ability to sense suppression signals from their own transponder/UAT transmissions and so they will pick up their own signal.

Most installed systems have that suppression functionality so this won't happen.

The suppression is simply a wire between the two units that if the transmitter is transmitting, it goes high, which tells the receiver to ignore whatever it is receiving at the moment.

So if you want to "receive" yourself, simply snip the suppression wire if you have one...


Why are sidestep ILS minima not used in EASA-land? (specific example: EGKK)

You use circling minima for sidestep manoeuvres. While not commonly practiced, they may be requested by the pilot, have done so many times when LEMD (MAD) is in N config, saves 20min taxi-time...


How would ATC try to establish contact with a VFR craft?

Long story short, ATC has no reason to contact you but if they were to try they'd probably use 121.5 (see below). You're not in their airspace and the whole purpose of that airspace is to ensure separation, so as long as you remain clear of it they won't be concerned about you although they'll probably report your position to the 747.

As for your specific questions:

That's your decision as PIC and no one else can make it. But I wouldn't spend much time in a zone where I'm at high risk of a wake turbulence encounter.
No, there is no requirement for you to be in contact with ATC in that airspace so you're not wrong. It would be good to get flight following if possible, but that's optional and might not be available anyway.
It's hard to say what "too close" means and it could change depending on the time of day, if you're thinking about traffic. Again, this is something that you as PIC have to determine.
They won't try to contact you since you're outside the class B and they have no reliable way to contact you anyway. And considering wake turbulence again, "too close for their comfort" is probably more like too close for your comfort :-) Aircraft size isn't a consideration for right of way (see 14 CFR 91.113).
They won't for the reasons above. And they also can't know if you have a working radio, which frequency you're on etc. But they would probably try 121.5 because a current FDC NOTAM states that you should be monitoring it if you can:

  ALL AIRCRAFT OPERATING IN UNITED STATES NATIONAL AIRSPACE, IF CAPABLE,
  SHALL MAINTAIN A LISTENING WATCH ON VHF GUARD 121.5 OR UHF 243.0.

The AIM also suggests and encourages all pilots to monitor it (e.g. section 6-2-4).

It's hard to say, the FAA's ATC instructions don't cover this situation (or I couldn't find it). But giving a specific bearing is unlikely (a bearing from what?) because you might not have the equipment to verify it so perhaps "12 miles north of DFW at 1500ft" would be more likely for the position part.

Of course, if ATC really, desperately, urgently needs to contact you - like if you fly straight through the class B without a clearance - then they can always request an interception. That would really ruin your day, so monitoring 121.5 if you can is probably a good idea.


What was in the noses of airliners before the weather radar?

(Source)

Externally, the Connie (shown above) had lights, with the red being the now obsolete passing light.

From the high-res DC-3 and DC-7 cutaways, all sort of stuff, from autopilot oil and air filters, wiring, windshield spray systems, to hydraulic reservoirs.

There wasn't one main object like there's now, nor was it completely empty. Its main aerodynamic function remains though.


What happens when all electrical systems in a helicopter fail?

The reason for the failure is important actually. If all the electrical systems on an EC135 helicopter fail in your classic EMP scenario then the helicopter has to make an emergency landing as the jet engine is run by a computer system which requires electricity. A power failure of that system would most likely cause the engine to revert to manual backup, which means it's still running but you need to get it down ASAP. It's also possible the engine could fail entirely, in which case the helicopter would have to autorotate, i.e. land without engine power, which is survivable, if hazardous and extremely exciting.

If you are asking about a more straightforward electrical failure of flight instruments and comms with the engine still running then the pilot would continue to fly the chopper and use backup instruments to complete the flight. Even fully "glass cockpit" aircraft have a set of "steam gauge" instruments, some which require no power whatsoever, like an altimeter and airspeed gauge which use air pressure measurements, a magnetic compass for navigation, etc. Some will also have a backup Attitude Indicator which is powered by an isolated battery system and would give the pilot attitude reference even in cloud or poor visibility. So it's less of an event that you might imagine, although instrument failure is always an interesting experience, trust me.


Why building a stopway instead of just building a longer runway?

Overrun areas are almost always filled with some form of loose material... sand, for example... that will slow a plane down with extra drag on the landing gear. The idea is that if a plane has reached the end of the runway, it's already in trouble and is probably having problems braking.


What is nominal n1 and fuel flow behavior during cruise climb?

I know that fuel flow should decrease with altitude (air fuel ratio). Should fuel flow also decrease with weight (fuel burn off)?

Yes, the lighter you are the less N1 you need to maintain the cruise Mach at your cruise altitude. This will result in a lower fuel flow (at fixed environmental conditions, lower N1 always results in lower fuel flow).
The maximum climb N1 is however independent of weight (see below for details), therefore also fuel flow will be independent of weight during climb (but the resulting climb rate is different).

  Is n1 kept constant? Does it decrease with weight? Is it unaffected by altitude?

The cruise N1 depends on both weight and altitude. The following table from the 737 NG QRH (Performance Inflight - Flight With Unreliable Airspeed) shows the target N1 values for various weights and altitudes:

As you can see, N1 goes up with weight and up with altitude. The maximum climb N1 has a more complicated behavior as function of altitude, as the following table from the 737 FCOMv1 (Performance Inflight - General) shows:

The last 3 columns all show climb at fixed Mach 0.78. The N1 usually goes up with altitude, but then slightly down again for the highest altitudes (this is because TAT goes down with altitude up to the tropopause, but stays constant above). The maximum climb N1 is independent of weight, but the actual weight will affect the resulting climb rate.

  If it depends, then what systems (fadec?) or settings (rated/non-rated mode?) are responsible for setting the behavior.

For the Boeing 737, the required fuel flow to reach the target N1 is computed by the EEC (Electronic Engine Control, see also What are the differences between FADEC and EEC systems?). From the 737 NG FCOMv2 (7.20.5 Engine System Description):

  Electronic Engine Control (EEC)

  Each engine has a full authority digital EEC. Each EEC has two independent
  control channels, with automatic channel transfer if the operating channel fails.
  With each engine start or start attempt, the EEC alternates between control
  channels. The EEC uses thrust lever inputs to automatically control forward and
  reverse thrust. N1 is used by the EEC to set thrust in two control modes: normal
  and alternate. Manual selection of the control mode can be made with the EEC
  switches on engine panel.

The target N1 calculations are performed by the Flight Management Computer, but can be overridden by the pilot. From the FCOMv2 (11.32.2 Flight Management):

  Thrust Management

  The autothrottle operates in response to flight crew mode control panel inputs or
  to automatic FMC commands. Reference thrust can be selected on the N1 LIMIT
  page. Automatic FMC autothrottle commands are made while VNAV is engaged.
  The autothrottle system:

And further (11.41.28 FMC Takeoff and Climb):

  N1 Limit Page

  [...]

  Normally, N1 limits are automatically specified. Pilot selection of other limits is allowed.

  Pilot selection of a reduced climb mode does not change the automatic selection
  for other phases of flight.

  Pilot selected mode is automatically replaced by AUTO selection when the
  autopilot next changes vertical mode.

  The active thrust limit is used by the autopilot and is displayed on the thrust mode
  display.


What does the airport fuel market look like?

Large airlines have standing, negotiated contracts with major airports to buy fuel (and almost always also other services like cleaning, catering, etc).  Some times these are fixed-price contracts, sometimes they float in relationship to the spot price of jet fuel, sometimes they are a hybrid.  You can think of these as any other complex financial relationships: almost any way you can imagine a contract to be drawn up, someone has likely tried it.

Airlines' operations desks also constantly monitor the price of fuel at different airports and different times - and in some cases airplanes carry enough fuel to make a return trip without refueling because it ends up being cheaper to carry the fuel rather than purchase it at the next stop.

For general aviation, the airport FBO (fixed base operation) generally has one and sometimes multiple fuel vendors on-site, that generally sell at a fixed price -- very much like a gas station for cars.  Obviously, airports that have more than one fuel vendor generally have more competitive prices, but even for single-vendor operations they can't make the fuel costs TOO high, or pilots will purchase just enough fuel to take off and go somewhere that gas is cheaper.


When a large commercial jet touches down, is it committed to stopping?

When a large commercial aircraft touches down, it is not committed to stopping.

However, it is committed to stopping when the thrust reversers are selected. This is because they take different time to stow and adding power while stowing would likely cause significant asymmetric thrust. And even if they don't, they take their time to stow and you are unlikely to have enough speed and runway when they finally do.

When thrust reverses are not selected, the pilots of course have to consider whether it is more likely that they can stop or lift-off again on the remaining runway. And they sometimes do choose to lift off. There are many incidents where planes went around after tail or even wing strikes or bounces as it's often easier to get the plane under control by adding power. But once thrust reversers are selected, stowing them again means loosing a lot of time and is risky, so go-around is considered out of question afterwards.


What is the average angle of attack of GA airplanes during takeoff?

Depends on how slow you are going at rotation, and how aggressively you rotate.
Stalling AOA of most GA wings is somewhere in the region of 14-16 degrees and on takeoff it shouldn't get above 10ish to have adequate margin.

The issues over taking off with frost is due to the frost reducing stalling AOA to an unnaturally low angle, say 9 degrees, so that the pilot gets a surprise during a normal pitch up.


What is Lower Traffic Area (LTA) airspace in France?

@mins Has answered the question in his comment above:

  LTA: FL 115 to 195, UTA: FL195 to 660" (Wikipedia). Created in 1992, a LTA is a class-D CTA (E over Alpes and Pyrénées to allow VFR gliders) between and excluding other CTA (airways and TMA), and up to 12 NM of the shoreline. I've highlighted a class-E LTA nearby Perpignan TMA and the Spanish border on this SIA map. Synoptics of the French airspace (source).


How do turbochargers aid engine performance as density altitude increases?

An oversimplification for sure: Turbochargers essentially compress the air going into the engine (cylinders) to maintain (near) sea level pressure internally, so the external density altitude doesn't affect the performance of the engine.

The "liability" at low density altutudes is that it is possible to over-boost the engine, potentially damaging it. See the related question for more in-depth explanation and the liability of having a turbocharger at low density altitude.


How does an Airbus pilot decide whether to use HDG-V/S or TRK/FPA guidance?

It's mostly up to points 2 and 3 on your list rather than personal preference:
Note that most ATC instructions (beit on departure,cruise or initial approach) will ask of you to fly a specific heading and/or a specific climb rate (v/s). This makes the hdg/vs mode the 'standard' mode to be used durring flight. This is also the mode where the F/Ds provide an easy to use guidance for the pilots to follow.
The reason for this Hdg preference for ATC is beyond the scope of this question, and is quite a nice narative on how historically we arrived at using heading for separation, but I will say this much: imagine ATC software attempting to interpolate the track of two converging a/c , to determine minimum separation and/or collision conflicts. Now imagine there is (unkown to the atc) changing wind along route, and both a/c will change hdg to maintain proper ground track. The math required is mind-blowingly complicated...(because changing hdg will change time of arrival at intersection,etc )
Anyway, once you look at some final approaches you will see that there is usually a final approach Track and a (3deg usually) glide path angle posted on the chart. The reason is that being closer to the runway, you start to become a bit more interested in your path wrt to ground rather that wrt to other trafic.
TLDR
TRK-FPA, as part of normal operating procedures, is only used when flying the final part of a non-precision approach, and is usually engaged  about 1 NM before the FAF.
Mind you, it's use is not prohibited outside of that, just there is kinda little use for it.


Why would seaplanes use a curved takeoff run?

Years ago now I gave a fair amount of instruction for seaplane ratings. I remember it quite fondly as seaplanes combine the fun of flying with aspects of the fun of boating. There were three conditions in which we used curved takeoff runs.

The most frequent curved takeoffs were on rivers, which tend to not run in a straight line, and even for those portions of a river that do, there may be rapids to stay clear of, so following the bend of a river or weaving between rapids was not unusual. In my case, the rivers were the McKenzie and Willamette, both in Oregon, USA. If you're ever in Eugene, Oregon, go down to Skinner's Butte Park on the Willamette River. On the upstream end of the park is the Ferry Street bridge. On the downstream end is the Washington-Jefferson bridge. In the 1970s we used to operate on the water between them, avoiding the rapids. We stored the airplane for a time on the Skinner's Butte Park shore line. That was legal and safe back then.

The next most frequent usage of curved takeoffs was to get off ponds that were not wide enough to allow a straight line takeoff. However, you can do it taking off in a curve along the perimeter of the pond. If you ever happen to fly over Daniels Field alongside Interstate 5 about 20 miles north of Eugene, Oregon, you'll see a lake/pond alongside the runway with a small island in the middle. There is no straight line you can draw on that pond that comfortably gives you room for takeoff, but you can circle the island and get into the air without difficulty.

The third circumstance we didn't have to use often was when we had to run across our own wake to be able to get up on the step on glassy water. For example, Waldo Lake in the Oregon Cascades is at 5,400 feet elevation. A J-3 cub with an 85 horse engine and with two people on board simply cannot get up on the step when the surface of the lake is a dead calm. However, if you get going in a curved path, you can get up on the step when you run across your own wake. Once you're on the step, you can then put the airplane up on one float and get enough airspeed to take off. Just as a matter of information, seaplane operation on Waldo Lake is now prohibited.


Is there an actual rated thrust for a Cessna 172 engine at takeoff power?

A fixed pitch prop will develop maximum thrust somewhere between static and maximum air speed depending on its pitch. Finer pitch will give better acceleration from a standing start, more coarse will give more thrust at cruise.  People generally do not quote thrust numbers with props, charts calculating weight and weather effects on performance are far more important than "thrust".

However, if you want to know, do it the same way James Watt did, either by lifting a weight, moving a weight, or lifting AND moving a weight.  Watt knew just to take the first meter, where air drag was negligible.  For a Cessna, I would take the first 100 feet, release the brake, and hold a stop watch.  As John K said, it should be 500-600 lbs.  F=ma.

Just keep in mind, the key to those performance charts is that weather conditions have MAJOR effects on power and prop efficiency (prop thrust), this is what you MUST be aware of before takeoff.


Why does the F-4's rear seat have a weather scope eyepiece?

That's not an eyepiece, it's a glare shield. The angle of the display made it susceptible to glare from light entering the cockpit. The shield made it easier to see, at night as well. My theory is that they got the idea from Star Trek. Spock had one too on his workstation on the Enterprise.


How many flight hours do the first retiring A380s have?

The A380 that was being scrapped was the 3rd aircraft on the production line. After being used for a short time in the test fleet of Airbus, it became the first line number that was delivered to a customer. (Line No. 1 and 2 are still owned by Airbus).

The first few aircraft leaving a new production line are usually heavier and have different wiring than later builds, because the production process has not yet been optimised. For example, the wiring in early A380 fuselage sections was too short, so that after assembling the fuselage they couldn't connect the electronic cables. This led to rework that added weight and complexity.

Therefore, the first few aircraft from the production line have higher fuel burn (due to extra weight) and higher maintenance cost (due to the one-off quirks that are not found on later aircraft). This makes such aircraft uneconomic to operate and difficult to sell.
If it is hard to make money with such an aircraft anyway (the long-range market clearly prefers twin engine aircraft with approx 300-350 passengers), scrapping it will bring the most value.

The aircraft was not at the end of its technical design life. The design life of long range aircraft is in the order of 30-40 thousand cycles (flights). With two flights per day it would take approx 45 years to reach that limit. See also  What is the lifespan of commercial airframes (in general)?

I wouldn't be surprised if a few other A380s with low production line numbers will be scrapped in the next few years. However, in general I expect that the A380 will be operated for another 20+ years,  especially on high volume routes to airports with limited capacity.


What does ® mean in the Chart Supplement (A/FD)?

According to the Chart Supplement (formerly the A/FD) legend:

  APP CON—Approach Control. The symbol ® indicates radar approach
  control

And:

  DEP CON—Departure Control. The symbol  ®  indicates radar departure
  control.

The FAA has different approach facilities classifications, a TRACON has radar but others don't. So you should see this symbol when the approach/departure services are provided by a TRACON or other radar facility.


Why is KOAK's alternate minimum higher than standard?

regarding non-standard alternate minimums -

From the US Terminal Publications, SW-2:
OAKLAND, CA
METROPOLITAN
OAKLAND INTL (OAK) ILS or LOC Rwy 12:

ILS, Category C, 700-2; Category D, 1400-3

If you plan the KOAK ILS RWY12 to Circle to another runway (e.g., RWY30, RWY28L/R, etc.) the published "no approach light" (ceiling/vis) minimums for your approach are:

CAT A/B: 600-1 1/4 (meaning Alternate Minimums are standard, i.e., 600-2, because 600-2 is higher than 600-1 1/4, the published ceiling/vis minimum without approach lights).

CAT C: 700-2 (meaning that this becomes the non-standard minimum because it's higher than the standard alternate minimum of 600-2)

CAT D: 1400-3 (meaning that this becomes the non-standard minimum because it's higher than the standard alternate minimum of 600-2).  Since 1400-3 is VMC, no "without approach light" additive (the 1/4 mile) is applied.

NOTES:

See inop component table for visibility additive -which is 1/4 mile vis added- when approach lights are considered inop, as required by TERPS when determining alternate minimums.
From 8260.3C, para. 3-4-1 a. (2): PA. For each approach CAT, select the PA’s ceiling and the PA’s visibility (without approach lights). When more than one line of PA minimums is published on the same chart, use the line with the higher HAT..


How can a part 91 operator gain authorisation from the FAA to perform RNAV (RNP AR) approaches?

I have no practical experience with FAA RNP AR authorization but the guidelines for obtaining RNP AR authorization from the FAA are described in FAA Advisory Circular 90-101A (FAA PDF). The whole process to go through is described in that document. It specifically mentions Part 91 and Part 91K (fractional ownership) so it should be possible to obtain permission for individual pilots.

However, it will not be easy for an individual pilot to meet the requirements.

You will have to perform a high number of RNP AR approaches under a provisional authorization in VMC or increased minima before final authorization is granted.

Luckily the FAA made provision for operators with a small fleet:

  NOTE: In unique situations where the completion of 100 successful
  approaches could take operators an unreasonably long period of time
  due to factors such as a small number of aircraft in the fleet,
  limited opportunity to use runways having appropriate procedures,
  etc., consideration of a reduction in the required number of
  approaches will be on a case-by-case basis. The FSDO/CHDO will
  coordinate with FAA HQ in consideration of an operator’s request for
  reduced interim authorization requirements.

You will need to arrange proper training:

  Initial training: With no prior RNP AR approach experience,
  each pilot
  must complete at least four RNP AR approach
  procedures: two as pilot
  flying and two as pilot
  monitoring.These four RNP AR
  approaches shall employ the uni
  que AR characteristics of the
  operator’s approved procedures (i.e., RF legs, RNP missed). You must fly two approaches to the DA and two approaches must result in an RNP missed approach procedure. Two of the above approaches will include interrupted approaches resulting in one approach with vectors to resume the approach and one approach resulting in a hold at an initial approach fix (IAF) or transition
  fix.

And in addition to the a qualifying aircraft the operator must have a program to ensure data the navigation database stays up to date and is of sufficient quality.

You will also need to implement a monitoring program to review your RNP AR approaches and detect any negative trends. Results from this program will need to be shared with the FAA on a monthly basis.


Can you receive traffic advisories without a specific destination or intention?

You call up ATC, tell them that you are out sight-seeing and would like flight following and traffic advisories.  On a workload permitting basis ATC would provide the service.
Here is an excerpt from the FAA Air Traffic Control Handbook:

Section 6. Basic Radar Service to VFR Aircraft- Terminal
7-6-1. APPLICATION
a. Basic radar services for VFR aircraft must include:

Safety alerts.
Traffic advisories.
(...)

This is a very common request and depending on the location there should be very little difficulty in receiving this service.


Is this frost or frozen bacteria in clouds?

If it disappeared after you descended, it was frost specks on the inside surface of the structural* outer panel, forming on dirt particles on the plexi, from the small amount of humidity in the cabin air that migrates through the little vent hole in the inner panel that is part of the interior fascia.

It's not a problem on cockpit windows because they are heated.

*I say structural, because the outer pane of quarter inch thick acrylic has about the same tensile strength as the adjacent much thinner aluminum skin and is part of the pressure hull.


What do numbers signify in airport codes?

The code for Markham Airport, CNU8, is a Transport Canada identifier.

The codes for the other airports are ICAO airport codes. ICAO airport codes always consist of 4 letters. Markham Airport does not have an ICAO airport code.


When talking about that sort of thing, you're really looking for single-point-of-failure weak links that are difficult to detect during a walkaround or inspection.  Hinges don't normally just let go with no warning.  They get loose and sloppy first.  Same with bellcrank bearings, rod ends, and pulley bearings.  Things in general on airplanes can get really loose and sloppy and still work because there are large fudge factor margins built into the design (like, a crack on a piano hinge might have to progress to 80% across it before normal loads would make it break).

If you're talking about "aileron failure" as in "spontaneous complete loss of aileron control", this is an extremely rare event.  If you had to pick something, you'd generally look for items that can just degrade with no obvious signs and then suddenly let go.  On the typical single-loop cable run control system you'll find in a Cessna or similar, that weak link is the control cable itself, at swages and where the cable bends to go around pulleys, or from corrosion.  The check for cable degradation, besides visual inspection, is to wrap a rag around the cable and pull it along feeling for wire snags (or you can use your bare hands if you enjoy the potential for surprise searing pain).

For cable corrosion, it can seem attractive to go with stainless cable, but stainless cable is weaker and SS doesn't like to rub against itself and the cable tends to fret and break down at pulley bends (why aircraft SS cable has a lubricant in it - the identical-looking SS cable you get at the hardware store doesn't).  In the transport world and in GA I think, you will find mostly galvanized carbon steel cable, which is stronger and doesn't break down as readily (the zinc is a very effective inter-strand lubricant, as well as corrosion preventative).

In terms of overall wear and tear, generally it's parts with moving bearing surfaces that see concentrated loads.  The aileron hinge closest to the control rod will always get loose and sloppy first.  The bearings in the bellcrank in front of the aileron where the bearings are under a constant radial pre-load from cable tension, on top of flight loads.  Pulley bearings at 90 degree bends where radial loads are high.  Pulleys and bearings oriented horizontally go bad sooner than vertical ones because the oil component of the grease in the bearing leaks out over time and the bearing rots out.

In the end though, most of the degradation isn't wear and tear, it's degradation from lack of use.  Like cars, airplanes do not do well sitting stationary for long periods, especially outside.


These are engine vibration measurements. The image you show is the Compact Engine Display:

  3 Vibration (VIB) Indications

  Displayed as digital readout only.

(Boeing 737 NG FCOMv2 - 7.20.1 Engines, APU - Over/Under - Displays)

The value comes either from the EEC (Electronic Engine Control) or the sensor directly:

  Oil pressure, oil temperature, oil quantity, and engine vibration are the secondary
  engine indications. [...] Engine vibration indications are displayed with a round dial/moving pointer.

  The EEC must receive electrical power to supply engine operating data to the
  flight deck engine indications. When the EEC is not powered, N1, N2, oil quantity
  and engine vibration are displayed directly from the engine sensors. Positioning
  the engine start switch to GRD supplies electrical power to the EEC and displays
  pointers/digits for all engine parameters.

(Boeing 737 NG FCOMv2 - 7.20.1 Engines, APU - System Description)

On the lower DU they look like this:

The amber warning line (2) shows the limit of 4.0 units. The QRH defines High Engine Vibration as:

  The vibration level is more than 4.0 units
  Airframe vibrations.

(Boeing 737 NG QRH 7.24)

As to what the actual number really means, the FCOM does not say. I could find this quote on pprune.org, but I cannot verify it:

  Two types of vibration pickups have been used on Boeing airplanes, the electomechanical velocity pickup and the piezoelectric accelerometer. Signals from velocity pickups are converted into vibration displacement, measured in 1/1000 of an inch, peak to peak (mils double amplitude). These units represent the physical displacement of the vibration sensor. Signals from accelerometers are converted into velocity, measured in inches per second (ips). These units represent the peak amplitude of the velovity of the vibration sensor. Boeing airplanes typically use a 0-5 scale for cockpit display of vibration. On earlier applications, the scale provides an indication of absolute vibration units (ips or mils da) as output from the airborne vibration monitoring (AVM) signal conditioner. This approach is not optimum in that a display of displacement units will provide relative insensitivity to low speed rotor vibration. AVM signal conditioners used on 737-300 and latter, 747, 757 and 767 provide output data in scalar units. These scalar units are uniquely tailored for each engine type to match the operating speeds and vibration characteristics of the engine rotors. The scaling used on the 737/CFM56 installation provides display sensitivity for the high speed rotor proportional to the vibration velocity. The low speed rotor vibration is displayed in units proportional to displacement, except near idle conditions where velocity scaling is used.

(Boeing Airliner magazine, OCT-DEC 1987 issue, emphasis mine)

So the number was originally based on acceleration in inches per second, but it is a scalar value today without a direct physical meaning. The only thing the pilots need to know is: around 1.0 is normal, 4.0 is the limit.

This page confirms, that scalar units are used on the CFM56-7B, which is used on the 737 NG series:

  The algorithm detects the highest vibration (in scalar units) of all four sections of the engine during the whole flight and takes a snapshot of the remaining parameters. The vibration data are transfered to the next flight leg upon engine start.

  The Vibro Meter Advanced AVM Signal Conditioner (AAVM) P/N 241-298-002-011/-015 is able to detect #3 or #4 bearing vibrations based on the CFM56-7B engine vibration signature.

(AviaDeCo GmbH)


Is the callout "minimums" on the 737 used to describe DH on precision approaches

DA/DH and MDA/MDH both get a callout of "minimums". The pilot is expected to know (from having briefed the approach earlier) which meaning applies. This is true for every FMS/GPS I've seen, not just the B737. On planes without this feature, one of the pilots will call out "minimums", and even a solo pilot (for smaller planes) should say the word to himself as a reminder.

While all pilots are required to understand English, it is best to assume their vocabulary is limited--especially during stressful situations or for urgent problems. Therefore, like ATC, planes use standard phrases--and as few of them as possible--to limit possible misunderstandings. If one general word can cover multiple situations, then that is preferred over having gratuitously different words for each one.


What is the temperature range of engine mounts connected to the pylon?

This is an order of magnitude educated guess:
Based on this picture from Wikipedia:

You can see that the aft mount is attached to the turbine rear frame.  As such, it'll get relatively toasty.  I'd say maybe 900 - 1000 F.
The forward mount is attached to the fan frame just above the compressor case.  As such, it will be much cooler.  Maybe 200 - 300 F.
Again, that's just an educated guess.  I'm not aware of any publicly available data.
Edit:
in response to the comment, no it's not the big red box at the front. That's approximately where the forward mount would be in a typical Boeing style engine, but Airbus does it a little differently.  In the below, I found an image of a model of the pylon (from here), and showed where the pylon meets up with the engine.  The left most line points to the aft mount, the middle line to the forward mount, and the forward line meets up with the inlet (not a mount, just to show you how it lines up).  The top orange bar in the engine picture, and the lower white bar in the pylon picture are ground support equipment.  Would be removed when the engine is attached to the pylon.


Is it possible to power a very small jet using batteries?

On some scale, of course this works -- look up "EDF", Electric Ducted Fan R/C models of jet planes.  For something the size of a Honda Jet, you still likely wouldn't get the performance (and certainly not the range) that you might desire.  Go smaller, and something in the size range of a BD-5J/Acrojet, which originally flew on a very small engine, might support being converted to an EDF -- though the flight endurance would likely still be very short.

EDF would be suitable for a motor glider or self-launch sailplane, neither of which depend heavily on long power endurance for normal operation (but neither of which are expected to fly hundreds or thousands of miles at hundreds of miles per hour, like a Honda Jet).


What is the maximum angle F-16 can turn in x seconds flying at corner speed?

To calculate this, you need to look at the energy Maneuver diagram for the aircraft. This diagram depicts, for a specified altitude and gross weight, the excess power per unit pound of weight the aircraft would have at full afterburner at any g-Loading and true airspeed. There would be a different chart for each aircraft configuration, gross weight and Density Altitude combination.

Instantaneous Turn rate is depicted on the vertical scale, true airspeed or mach number is depicted on the horizontal scale. The concave curved lines that go from upper left to far right represent flight conditions of constant G-loading, while the straight lines that radiate from the origin represent constant turn radius. The peak of the flight envelope, (at about Mach 0.7, 20 deg/sec turn rate and 8 Gs, is corner velocity. The lines that start at the left boundary or at the bottom, go upwards, curve to the right and then back down again, and are labeled with values 600, 400, 300, 0, -200, etc. are called Ps, (pronounced P-sub-S), lines. They depict the specific power, or actually, specific excess power - a measure of how much power per pound of aircraft weight the aircraft would have left over to climb or accelerate at the depicted point on the diagram.
So at the top of the diagram, at the corner velocity, where the turn rate is near 20 deg/sec, the specific excess power is less than -800. The -800+ Ps curve indicates that the aircraft, if it established flight at those conditions, would be bleeding energy (airspeed or altitude) at a rate in excess of negative 800 ft/sec.

The best performance on the diagram that can be sustained, on the other hand, is the highest point on the zero Ps line, which is at mach 0.8, 7 Gs, and it would produce a sustained turn rate of just over 14 deg/sec.

So, in a level turn, at Mach 0.8, 7 Gs, and 14 deg/sec, the F-16 could turn 180 degrees in about 13 secs.

Of course, if the aircraft performs the turn in a descent, it can make the turn in less time. This is indeed a common training maneuver, to turn 180 degrees in the shortest amount of time possible. It is performed by rolling into 135 degrees of bank at or slightly above corner velocity and pulling at maximum G-load. The maneuver is performed at maximum available G-load, in a constant plane tilted at 45 degrees from the horizontal. Bank angle (starting at 135 degrees), decreases throughout the maneuver, reaching 90 degrees bank after 90 degrees of turn, and 45 degrees bank at the end of the maneuver (after 180 degrees of turn). At 15,000 feet MSL, this will generate almost 20 degrees per second, and can be done in about 10 seconds.


Carbureted Rotax engines have no mixture control, how do they handle less dense air?

According to this owners manual

4.5 High altitude compensator (H.A.C. kit)
H.A.C. is a high altitude compensator developed by ROTAX which adjusts the air/  fuel
mixture automatically from sea level to 6500 m altitude using a
special BING  carburetor.

This page has information on how the Bing carburetor works (with pictures!):

Here's how it works
Did you ever wonder what makes fuel flow up the jets, from the
carburetor float bowl, enroute to the engine? Is it vacuum at the
venturi?  That's not quite descriptive enough. It is better defined as
a differential pressure between the float bowl and the venturi. What's
the pressure in the float bowl? Here is an important hint, the bowl is
vented to outside atmosphere. So, it should be the same atmosphere, or
ambient pressure, that's feeding the airfilter.  If it is not,  the
differential between the venturi and float bowl is going to change and
so will the mixture...Maybe richer, maybe leaner. Just think of that
for a second. If  fuel air mixture can be thrown off, accidentally by
improperly venting the the float bowls, why not control the venting to
effectively control mixture? That's exactly what your Bing 54 can do,
automatically, when a High Altitude Compensator is added.  If
pressure in the float bowl is reduced, relative to the venturi,  less
fuel makes its way up the jets, and consequently, mixture is leaner.
The HAC unit has two chambers separated by a diaphragm. One chamber is
completely sealed (except during calibration) and air density within
remains constant. The other has airfilter, float bowl, and venturi
connections, so air density on this side is variable. It is in this
chamber, that ambient pressure can be reduced by feeding it to the
venturi via a connection on late model carburetors. The amount of
ambient reduction is controlled by a tapered needle which changes
position with deflection of the diaphragm. Think of the diaphragm as a
flexible wall between two chambers that allows the sealed side to
expand or contract as changes in ambient pressure occur on the other
side. The reduced  (from ambient) pressure gets routed to the float
bowl(s) via their vent lines with a resulting leaning affect..  If
that supply of low pressure is shut off, float bowl pressure returns
to ambient, and the mixture goes as rich as the jets will allow. With
HAC installations, standard jetting starts out several steps richer.
This is why we say the default, or failure mode is typically toward
the rich side.


Were there ever instrument approach procedures utilizing only Four Course Range Navigation?

Yes such approaches have existed.

As early as 1944 the North America Low Frequency Radio Range (aka Four-Course Range and Adcock Range) network was quite developed. There are several approach plates using this type of radio aid, e.g. this one from May 1944 for Meridian:

Source

The station is used for IAF and FAF. The approach is done using 334°/154° headings. None of them, nor the station are aligned with a runway, this looks like a circling maneuver.

Other plates:

Fort Chimo (Quebec)
Joliet (1957)

Some editions of the AAF Radio Facility Charts can be bought online, but the edition of June 1944 has been scanned by North Texas University:

On pages 38-39 we can see the overall coverage.
Other pages show details by area.

This is the page for Mississipi with Meridian, the airfield we discussed above, at the center:

We see that two of the four identified directions are not connecting airway segments. This is the ones used to approach the airfield where the station is located. They cannot be aligned with the runway because they play their role in the four-course range: There are four beams radiating over about 90° in azimuth, with small areas overlapping (about 4°). The middle axis of such areas is the actual path:

While the station location can be selected, and there is a certain possibility to have unequal quadrants, the adjustment is still limited. One or two directions are used for the airway(s), they determine the overall orientation of the other antenna system (angle bisector), and it's anyway difficult to create a small aperture (i.e. a very directional beam) at this frequency. This explain why the approach is a circling one.

Complete list of US approaches

At some point modern standardized plates were issued:

(Source)

The image below can be found on this site dedicated to simulation, which lists about 400 approaches in the US and Alaska.

More:

On Youtube: The Four Course Radio Range.
On Wikipedia.


How is the static pressure in the pitot static system reconciled when there are two outside static pressure ports?

I work on corporate jet aircraft and perform troubleshooting, testing, and certification on pitot-static systems.

The reason aircraft have static ports for each pitot static system is to equalize or average out the small differences in static pressure caused by crosswinds when the aircraft is in flight. The difference in pressure caused by crosswind components on the static systems is not in the psi range, rather it is in the millibar or 1/10 of inches of mercury (inHg) range.

14CFR, Part 43, Appendix E, Table IV "Pressure-Altitude Difference" lists several baro-scale test points and associated altimeter readings used when certifying the altimeters. From the chart you can get an idea of how a difference of 1/10 in-HG  will case a change of 90 to 100 ft in the altimeter reading (you can Google this table yourself).

An aircraft could easily have a difference in barometric pressure between the up-wind and down-wind sides of the aircraft when flying in a crosswind and this would cause an error of 100 ft or more on the altimeter reading if there was only a single static port located on one side of the aircraft.

On large aircraft which require 2 pilots, there are two completely separate pitot and static systems for each of the flight crew. Each pilot's instrument panel has its own altimeter and airspeed indicator (or air data computer) and display of altitude and airspeed information. There is a single pitot tube for each crewmember's instrumentation located on his side of the aircraft, but each crewmember's static system has two ports, one  on each side of the fuselage which reduces the error effects of crosswind on the altimeter (static) systems (total of 4 static ports).
For peace of mind and safety, the flight crews continually compare (cross-check) each other's altimeter readings and if they see an error of 80 ft or more between the two systems they have an uneasy uncertainty about which altitude is correct and they will bring it to the mechanic's attention.

A blocked static port is a funny thing to troubleshoot, because a flight crew will say they saw a big altitude difference on one leg of the trip, then the next couple legs it was fine, then it had a split again. Next crew will fly and say there were no problems, followed by another crew complaining about splits. If you question the crews and ask if they were experiencing heavy crosswinds when they had the split they will say, "hmm, now that you mention it... yeah, we had some heavy crosswinds".
We then connect our pitot-static tester to each side's pitot tube and one of each side's static port, block off the opposite static port, and bring the airspeed and altitude up on the tester. What we are looking for when we connect the tester to the obstructed static port is a split between the captain's and first officer's altitudes. (Actually the obstructed side will start to wind the Airspeed indicator up really fast and can damage it if you don't stop the test quick enough).

One side is obstructed and the difference in static pressure caused by the crosswind is throwing off the altitude reading on one of the altimeters.
Two ports per system is to reduce errors in the altitude indication.


IFR requirement for altimeter question (i.e. +/- 75 feet)

Barometric pressure isn't a constant. Just because you're at sea level, doesn't mean the air pressure is going to be exactly 29.9212 inHg. That's just the average sea-level pressure. So, for instance, if the sea level pressure is currently 30.9 inHg, then all altimeters in the region are going to read 1000 feet below the actual altitude of the airplane.
Those fluctuations are the point of the altimeter corrections provided by AWOS/ASOS/ATIS. By entering the actual sea-level atmospheric pressure into the altimeter, you can correct for those fluctuations and get a more accurate reading of your current altitude.


What is the relationship between Angle of Attack and Angle of Incidence?

Not really.

The angle of incidence is the angle between the chord of the wing and the longitudinal axis of the airplane.  But the plane is mostly free to pitch as necessary.  So if the best thing is for the wing to have an AOA of 11°, then it can pitch to that point.

Now if the angle of incidence were too different, it could increase drag on the climb-out, or the thrust angle might be less than optimal.  But there's no direct relationship.

The angle of incidence is a figure about the geometry of the plane.  The angle of attack is how the wing is oriented to the wind.  They don't "add" together.

If you did the math the other way (AOA - AOI), you'd find the angle the wind is making with respect to the airplane axis, not a figure that you tend to need.


What do the levels stand for in French Air Traffic Service Levels?

This NOTAM concerns the fire and rescue level not the ATS operating hours.

You can find the description of the fire and rescue levels here.

The reference of the ATS hours is to say the level is raised during the opening hours of the ATS.

The ATS opening hours are available on the Visual Access Chart from the SIA. (French service for aeronautical information)

Where you have on last page:

  SUMMER 0700 - 1800

Finally for the language, you have to speak French when the ATS is closed.


Charts are updated regularly by the FAA and expired charts should not be considered legal for navigation. Your chart must be current as per the date range printed on the cover for it to be considered reliable. That being said in my experience the VOR frequencies remain constant although I'm sure you can find instances in which they have changed over the years I have yet to see it happen.

FWIW the FAA is slowly shutting down the VOR system as GPS has become the prevalent navigation method.


Lights at the end of both wings of any airplane

Same as on ships, the navigation lights (green on right side, red on left side, white on aft tip) are there to allow visual judgement about another vehicle‘s position and orientation (and thus relative headings) at night. E.g:

if you see red and green, you are looking head on at another vehicle
if you see only green, you are looking at the right hand sector of the other vehicle
if you see red and white, you are looking at the left hand aft quarter

and so on.


Can an aircraft re-pressurize at high altitude?

Pressurization is controlled by two processes: air in and air out.  Air is constantly being let out of the cabin through (at least) 2 outflow valves, typically located at the aft limit of the pressure vessel.  Air is let into the cabin through the air cycle machines (a.k.a the "packs") which are provided with very hot and high pressure air from the compressor stage of the engines and eventually output into the cabin through the air conditioning vents.

During normal cruise flight, the mass flow rate of air into the cabin is constant (because the flow rate through the engine compressor is constant), thus pressurization is maintained by actuating the outflow valves.  Open them up a little more to raise the cabin altitude, close them up a little more to descend the cabin altitude.  Note that while maintaining a constant cabin altitude the outflow vales are partially open -- the incoming air is more than adequate to pressurize the airplane.

When a main cabin door or something bigger is opened, the airplane will no longer maintain pressurization and everyone must don oxygen masks to avoid unconsciousness.  With a planned cabin dump, masks will be donned before the cabin is evacuated, which will happen before any doors are opened.  As noted by others, the pilot oxygen is fed from cylinders of pure oxygen and will last a long time.  Passenger emergency oxygen is from chemical oxygen generators and lasts 12-15 minutes.  I'm not sure what type of oxygen masks the HALO jumpers would wear, but presumably they have portable oxygen for the jump not related to the airplane oxygen facilities.

When all of the jumpers are away the doors are closed and once again the airplane is capable of pressurization.  The outflow valves will be commanded closed and the cabin altitude will start descending.  Once the cabin altitude is back down to normal levels, the crew will remove and stow their oxygen masks.

There is no need to descend to accomplish this because the air provided by the engines is much higher pressure than even sea level air.  Re-pressurization is accomplished by closing up the airplane and letting air accumulate in the cabin, thus raising the pressure.  Once the target pressure is realized (~8000 ft), then the outflow valves partially open to stop descending the cabin and to maintain the target pressure.


What data does ACARS send back to base? Can it be used to track a plane?

Can ACARS be turned off? Would this generate a warning at the base station?

Yes, ACARS can be turned off.  See another answer of mine for more details.  Typically other systems use ACARS to send reports on a regular basis to update position and track other information, plus on an "as-needed" basis for abnormal things.  It would be up to the individual airline to look for these reports and to generate a warning if one didn't check in at the expected time, but I don't believe that they do this.  There is a lot of variation in the communication systems and they aren't 100% reliable so a lot of false alarms would be triggered.

  Can ACARS send postion, altitude and heading information automatically?

ACARS itself can not, but other systems like the Flight Management Systems (FMS) or ADS-C on board the aircraft can use ACARS to send reports like this automatically, and in some cases they do.

  Can ACARS be pinged to track an aircraft's position and heading? Would this require any intervention by the pilots?

Again, ACARS is simply a communication system.  A message can be sent via ACARS which will forward to the appropriate system requesting this information and have it respond.

  Is this system standard on commercial airliners?

I believe that most airliners that travel over international waters have ACARS, but I'm not sure if it's a requirement or not.

  What data do Airlines collect from the ACARS, if any at all?

This varies from airline to airline, but messages at the beginning and end of the flight (used to track flight time, etc.) and periodically during the flight are typical.  Usually periodic position updates and abnormal system indications are included as well.


Why are some contrails longer than others?

It is a mixture of factors. All else being the same:

a contrail at a higher altitude will last longer (the lower temperature slows the sublimation of the ice cristals)
a contrail formed in air with higher humidity will be bigger and last longer (more water is being turned into ice)

If there is not enough (relative) humidity, the contrail will not form at all. See for example this image:

Image from NASA

The contrails start forming on the east, near the clouds where you have a higher humidity, and do not form on the west, where no cloud is present and you have higher temperature/lower humidity.

  I've often noticed that planes flying on more or less the same track, headed in the same direction leaves different contrails.

What you observe might be airplanes flying at different altitudes and thus encountering different humidity/temperature combinations, giving birth to contrails with different histories.


How exactly does a pilot engage the autopilot?

“One Switch” to operate the Autopilot is not true. That’s just the movies.

Autopilot systems vary in each aircraft. Larger jets have it divided into two: Auto-Throttle and Auto-Pilot. Smaller aircraft/piston aircraft don’t really have auto-throttle capabilities.

The Autopilot is not just to “maintain” current flight path. It really can fly the entire flight from take-off to touchdown. This includes flying a departure procedure, en-route navigation, arrival procedure, an approach and touchdown.

Theoretically, it is possible for a pilot to not touch the aircraft controls (yoke/stick/throttle) after liftoff all the way until touchdown even if the mission is a complex IFR flight. Realistically, pilots love to fly and they will fly.

Many settings exist for each autopilot system, and these include (but are not limited to):

Lateral Navigation

Heading Mode (fly the “selected” heading”)
Nav Mode (fly the “selected” nav course)
Roll Mode

Vertical Navigation

Altitude Select Mode (Maintain the selected altitude)
Vertical Descent with a fixed speed
Vertical Descent with a fixed rate
Approch Mode (Vertical Descent with Glideslope)

Auto-Throttle

Maintain Selected Airspeed
Accelerate/Decelerate to Selected Airspeed

However, there is that master AP Switch that’ll disable all things related to the AP.


Which aircraft manufacturers still include Vertical Situation Displays (VSD) feature in their cockpits?

VSD

Boeing have a patent on a VSD (Vertical Situation Display), which is part of the Honeywell EGPWS (Enhanced Ground Proximity Warning System) which first appeared as an option on 737s about twelve years ago I think.

  The system will be offered by early 2003 as a customer option on in-production 737s and by retrofit on 737-600/-700/-800/-900 airplanes already in service. Implementation of the system on other Boeing models is under consideration.

- Boeing "Aero" magazine

I don't know if Boeing offer licences at acceptable terms to their competitors, or if Honeywell make available, to other aircraft makers, products that incorporate features licensed from those patents.

CFIT

It is possible that other manufacturers have equivalent options for alerting pilots of potential CFIT (Controlled Flight Into Terrain).

TAWS & EGPWS

The FAA, for example, requires aircraft be fitted with systems that comply with TAWS (Terrain Awareness Warning Systems) requirements. EGPWS systems satisfy that requirement.

TAWS requires a terrain awareness display but I dont think it requires something specifically like Boeing's VSD.

Airbus for example, on at least their A350 and A380 models, have a navigation display that incorporates "vertical flightpath data". I guess they don't call it a VSD. They also have what I think is a fairly common type of terrain display showing "peaks" ahead of the aircraft.

- Sources: FlightGlobal and Airbus

RNP

It may be that some of the issues addressed by the VSD are, for many airports in mountainous terrain, taken care of by RNP (Required Navigation Performance) which prescribes the required navigational accuracy of the aircraft's navigation systems. Generally the aircraft is required to be able to follow an approach path that consists of a sequence of curved three-dimensional paths to the runway that avoids terrain. I imagine this path is pre-programmed into the navigation systems along with the go-around paths.


Ramp refers to the area in airport where the aircraft are parked. This term comes from the days of seaplanes. From this site:

  The term ‘Ramp‘ traces its roots back to the days of seaplanes when there literally was a ramp from the water to the terminal parking area.

In case of seaplanes, the area is actually an inclined plane between the shore and water. This is similar to the term boat ramp.

Note that this is used mainly in US. The ICAO (and FAA) terminology for the area is Apron.


What are the technical details of how airline seats are installed on an airliner?

Economy seats are removed (and installed) row by row. The row of seats (typically 2 - 5 individual seats) are bolted to a track on the airframe floor. You can see them being removed in this video (~18:30) during a D-Check. The rows are usually held in place with bolts, often in the corners and where seats meet. You can see an example bolt pattern here.

Modern First class seats (the more sophisticated individual ones) will be removed one at a time often with the whole entertainment center around them. The above linked video also shows this.

And, of course, installation is the reverse of removal.


What is the procedure for restarting an F-16 in the air?

There are a lot of questions rolled into one here, and I can't answer specifically to the F-16, but a turbine engine needs the same three elements from the basic fire triangle to run:  Fuel, Air, Ignition.  The element missing from the sequence description linked in the question is ignition.

The igniters are like spark plugs, and they are probably energized during actuation of one of the other mentioned switches.  Most likely the JFS switch has a secondary function of energizing the ignitors since it is engine start specific.

Airstarts are not an overly complex procedure, in fact for a single engine aircraft like the F-16 they need to be brief and committed to memory because fighters don't have the best glide ratio.

Fuel - Make sure the throttle wasn't inadvertently shut off, likely the checklist will call for placing this in the idle position.  (you need fuel flow, but don't want to dump too much gas into an engine that isn't lit yet!)  Perhaps there is a step to turn on a boost pump or switch tanks.

Air - Airborne this comes from outside ram air pressure, as measured by airspeed.  The minimum airspeed required envelope will vary with altitude, but most pilots will have a number committed to memory that will provide reliable airstarts across a broad range of altitudes.

Ignition - There will likely be a separate igniter switch for airstarts.  Press and hold until lightoff is achieved, then advance the throttles smoothly and resume flying.  The airstart ignitor switch is generally located on the power control lever for convenience.  If single engine, an alternate electrical power source may be required first in the form or activating a Ram Air Turbine or other source of emergency power to provide a spark if the generator is disabled.

The process isn't really any different from lighting a natural gas stove or propane grill that has a piezoelectric lighter - You turn on the gas and hold the button down or press repeatedly to make the igniter spark until it lights, then release the button and adjust the flame.  (in fact when testing the airstart igniters on the ground before flight you listen for a clicking sound to indicate they are sparking!)

So, in its simplest form a generic airstart checklist for a tactical jet would look something like the following example:

AIRSPEED - Maintain 200 KIAS minimum.
THROTTLE - Idle.
AIRSTART BUTTON - Press and hold until light off.
If no relight by 5000 feet AGL - EJECT


What are the maximum possible stabilizer and elevator deflections for the A320?

As per the A320 flight manual (§127.20 p3), the maximum permitted total pitch alteration in normal law depends upon speed, aircraft mass, CoG, and other factors:

Pitch Attitude Limitation:
Pitch attitude is limited to:

30º nose up in conf 0 to 3 (progressively reduced to 25º at low
speed)
25º nose up in conf FULL (progressively reduced to 20º at low speed)
15º nose down (indicated by green "=" symbols on the PFD's pitch scale)

The flight director bars disappear from the PFD when the pitch angle exceeds 25º up or 13º down. They return to the display when the pitch angle returns to the region 22º up to 10º down.

Likewise, the maximum physical elevator deflection is 30º nose up and 17º nose down. The maximum trimmable horizontal stabiliser deflection is separately 13.5º nose up to 4º nose down, but the plane will always fly within the total pitch limits specified above.
Good luck with your project!


How did the Brazilian Civil Aviation Authority have MCAS on paper from Jan 2018?

Of course the airlines knew about MCAS.  Do you think the maintenance manuals, maintenance program documents, tech training, wiring diagrams, and all that stuff was left out so it was totally top secret?  There would be a controller, wiring and software on board even though there were no cockpit indications or controls, so certainly the techs who might have to troubleshoot it, and others on the tech/engineering side, would know.

All that happened was MCAS was excluded from differences training, as that document shows, so that it was not included in the ground school differences course pilots took when moving from one 737 model to another (avoiding sim time, which was the point).

So pilots never got a formal briefing on its existence, and it could just be considered part of the "PFM" of the various black box systems who's level of function is too in-depth to be included in pilot training (PFM means "Pure F-ing Magic" and is a term instructors use to describe black box function that is beyond the training because covering it would extend the course to months).

I have little doubt there were pilots, those who dig into the aircraft more deeply than most and might even peruse maintenance manual descriptions, who would have known of the system, but just not on an official level, with official procedures and protocols that affected the flight crew.

Sort of like the subsystem that applies the brakes after you lift off to spin the wheels down right away. It just does its thing in the background, and pilots may or may not be aware of it, but everybody on the technical side does.


You have to have some way of holding the surface at other than where it wants to naturally trail in the airstream.

Your options:

Hold it yourself with control pressure. Becomes a pain after a while.  Some very simple homebuilt designs don't have any pitch trimming device and they have only one trim speed where they will fly hands off, the trim speed more or less controlled by stabilizer incidence; to fly faster or slower you have to hold continuous pressure on the stick.
Put a spring in the control circuit, a bungee, where the spring can be tensioned with a trimming device, usually a lever or screw device with a friction lock of some sort, to hold the continuous control force in the control circuit so you don't have to.  Gliders do this, and some light airplanes and homebuilts for pitch.  Works really well for aileron and rudder trim and lots of GA use bungees for the rudder.
For pitch trim, make the horizontal stabilizer incidence adjustable from the cockpit.  The elevator itself just trails when hands off the controls.  The fabric Pipers and Cessna 180/185 family do this, but you have a screw jack device and a pivoting stab attachment etc., so it's a bit complicated.  The fabric Pipers also combine the screw jack with a bungee interconnecting the elevator and stab so the stab applies a bit of elevator force when it moves, giving a bit more overall authority.
Use an external servo device to apply a force to the surface.  You have the air blowing past, so why not stick another moveable surface at the trailing edge that can move independently of the main surface, and apply an aerodynamic servo force.  A bit more drag than a bungee trim or adjustable stabilizer, but much more sensitive and versatile.  Much lighter and less complex than an adjustable stabilizer.

Probably 80-90% of the airplanes with manually operated flight controls use trim tabs for pitch trim because it's just the most elegant solution taking in all the considerations - light, simple, effective.  Tabs are less common for aileron or rudder until you get up to  airplanes over 5000lbs or so and you tend to see bungees or nothing, or little fixed bent metal tabs that only trim out to a single flight condition.


1. Spins are less frequent on large aircraft

They are less maneuverable
They are flown by more experienced pilots
They have more protection systems (e.g. flight envelope protection, yaw damper) to avoid uncontrolled flight

2. Spins may cause structural damage on large aircraft
The larger the aircraft, the lower its tolerance to stress. While one can quite comfortably spin a Cessna or Cherokee, attempt one on a Boeing 777 and things will break. Gear doors, the bolts holding the vertical stabilizer as well as cabin accessories are not designed to handle stress in that direction, not to mention engine flame-out.
3. Spins may not be recoverable
As discussed in this question.


Do pilots ever suffer PTSD after emergency landings?

Yes, for a while: Capt. Al Haynes, after saving 184 lives on United Flight 232.

I was lucky enough to have dinner with Al Haynes a few years ago, and he told me that he had a very difficult time overcoming the guilt of the disaster. The talks he gives have been a way of coping.  (As a side note, he also donates all the money he receives from the talks to the survivors of the crash).
Capt. Haynes has said the same thing in various interviews:
The Seattle Times:

Haynes said it took many sessions with a psychiatrist to overcome his
survivor’s guilt. He resumed flying three months after the accident;
mandatory retirement at 60 followed two years later. [link]

NY Mag:

It was very hard to get past the guilt of surviving. My job had been
to get people from point A to point B safely, and I didn’t do it. I
felt that I had killed them. I had a lot of psychiatric help at the
hospital and afterward. Finally, one psychiatrist said, “You’re not
going to find an answer. You just have to accept that it happened.” [link]

AvWeb:

Haynes said, at the time, that he remained troubled by the accident
and constantly wondered if there was something he could have done,
some overlooked decision that would have saved all aboard. [link]

Before his death, Denny Fitch said something similar:

"To find out 112 people didn't make it, that just about destroyed me,"
Fitch once said. "I would have given my life for any of them. It was a
really tough time." [link]


People say that modern airliners are more resilient to turbulence, but I see that a 707 and a 787 still have the same G-rating. Why is this?

Note that the 2.5 g limit is for load due to manoeuvring, not only for turbulence. The certification specification for large aircraft on the subject of turbulence and gusts has changed several times since the certification of the Boeing 707.
Turbulence, and its effects on aircraft, is nowadays much better understood. Different aircraft react differently to the same turbulence. What will result in a high g-load in one aircraft, may be a moderate g-load in another. Therefore the certification regulations now focus on prescribing the type of turbulence that needs to be safely dealt with, instead of the resulting load factor.
In 1964, a formula was introduced describing the gust load that the structure aircraft has to deal with. This was added as FAR 25.341. This section has subsequently been updated in 1990, 1996 and 2015.

Modified from my earlier answer to a related question


How long it takes for Pilots to prepare for landing?

This varies a bit based on company or personal standard operating procedures (SOP's).  However, typically a pilot/crew will receive arrival airport information either via D-ATIS (Data Link-Automatic Terminal Information Service) sent directly to an aircraft's on board equipment (e.g., ACARS - Aircraft Communications Addressing and Reporting System), or the same information converted to speech for those aircraft not equipped with an ACARS (or similar receiving system).
The information received generally includes the latest airport weather information, runway(s) in use, type of approach to expect (ILS, Visual, etc.), and any additional relevant information a pilot/crew would need to know before arrival for planning purposes.
For air carrier/high altitude type arrivals the crew generally will access the ATIS prior to the planned "Top of Descent" (TOD) point where the descent from cruise altitude will begin. It would not be uncommon to access the ATIS information 10 minutes (or more) prior to the TOD point (in a relatively lower workload environment) in order for the crew to properly prepare for arrival.  This preparation would include accessing the appropriate charts, perhaps inputting information into the onboard navigation/performance computer systems, briefing the approach procedures to be used, missed approach procedures, runway exit procedures, any special instructions noted from the ATIS.
Once the descent began (past the TOD point) and the landing preparations all completed and briefed, it could take 20 - 30 minutes before actual touchdown (or more).  This would vary based on ATC requirements, traffic conditions, vectoring, weather, etc.
For light aircraft/low altitude arrivals, the procedure the pilot/crew would take would be fundamentally similar.  ATIS information and arrival preparation would (should) be done early enough to allow for the least distraction and done in a relatively low workload environment (prior to a higher -  close to the airport - workload environment).
Again, different pilots and company SOP's may call for different procedures, but the above is common in my experience.


What if one of the navigation lights failed to function on a certified aircraft?

In the US, you would not be able to fly that particular aircraft at night and/or IFR since IFR flight requires all day and night equipment to be operable according to Title 14 Part 91.205. Only VFR day flight is allowed.

You would need to check your Minimum Equipment List and/or Kinds of Operation Equipment List to see if the manufacturer would allow flight with that particular piece of equipment inoperable. Then, placard the position light switch as inoperable. It would be best to get it fixed ASAP, just in case you or the next pilot to fly that plane has a flight run late.

If you are already in flight when you noticed that the position light failed, you handle it just like any other failure. Land as soon as practicable. To do this in the case of no position light while VFR at night, I would immediately get on flight-following and explain to them the situation. If you are already IFR, simply inform ATC of a position report with a safety of flight change.

I would prefer to land at an airport with an operating control tower with radar. I am lucky in the fact that I have a few nearby. Just be wary that the failed light is just a failure of the light. And, that it is not indicative of greater electrical failures.

Also, make sure your Transponder is operating in either mode C or S. And, make sure both your ADS-b in and out are currently operating as a safety net.


Which evacuation incidents were followed by a large fire?

I doubt there is a worldwide statistics.

The accidents, where actual fire broke and did cause significant damage will be well known and listed on the aviation safety network. However the precautionary evacuations that turned out to be false alarms and when nobody was seriously injured may fall through the cracks and not get reported anywhere. They should be reported to the overseeing safety board and that usually publishes at least summary list, but the system works better in some countries and less in other [1]. And there is no central store for these reports in either case, so you could try to collect the numbers for one country (according to [1], the reports are probably most complete for Canada), but that will be too few cases for decent statistics and worldwide data will be incomplete to the point of being useless.

However, I am pretty sure the balancing is right. Not only do fires happen, but when they do, they are fast. The China Airlines flight 120 at Okinawa on Aug. 20th 2007 burnt down in about 5 minutes. The first explosion occurred just few seconds after the last passenger left the plane and while the flight crew was evacuating. So if they waited any longer, it is quite likely someone would have died.

In contrast most evacuations don't result in injuries and the few cases are mostly bruises, some sprained ankles and if someone has really bad luck, some broken leg or hand.

The broken bones (and not sure, but I think even the sprained ankles) count as serious injuries. So that's the options the captain is comparing. If they command evacuation, somebody might break a leg, but if they don't and the fire is real, somebody will die. And they must decide in couple of seconds for the evacuation to be successful. So they would obviously err on the side of caution and command the evacuation if they have a good reason to think there might be a fire.


What are the ICAO GNSS waypoint naming conventions?

There are no "GNSS waypoints". GNSS is a common position source for RNAV, though not the only one.

All RNAV waypoints, like conventional (e.g. VOR/DME) fixes, have an identifier composed of five alphanumeric characters that is unique within a country. Some countries don't use numbers (e.g. the US); others do.


Why do jet engines take a long time to throttle down?

The simple answer is rotational inertia, once you get a heavy mass spinning fast that heavy mass will have a tendency to continue spinning fast unless something else is acted upon the object. Piston engines have a great deal of friction between the piston walls and pistons (how they hold the explosion in) this helps them slow down faster than a jet in which the turbine is made to easily handle this thus the joints are very well made and very free moving. While cutting fuel will keep the engine from continuing to generate thrust the turbine will continue to spin until a force causes it to stop (drag and friction really).


Where to find US airport weather Service Levels?

The last of the service standards issued by the FAA was a 2014 report and ONLY available via a FOI request.

According to AJT-21, the yearly updates have been discontinued (without giving any reason that we are aware of).  Last "published" report was 2013.

If you wish to see it, please email @ wxobservers@yahoo.com


Why is the XB-70's Top speed only about 60mph higher than its cruise speed?

From the excellent point in the comments, the XB-70 was designed for one thing; speed. It was, until the Blackbird, the fastest manned air-breathing aircraft. It was intended to outrun Soviet interceptors like the MiG-25 and fly higher than ground-based anti-aircraft weapons of the day, making it a possible first-strike weapon. As such, it wasn't going to loiter around at 80% throttle.

A second point is that since the B-70 project was cancelled for several reasons (cost projections, development of ICBMs and of high-altitude fast-tracking SAMs), the two prototypes were used primarily as testbeds to push the envelope of air-breathing craft. As such, data regarding their fuel efficiency curve was secondary to more basic problems of aircraft design for hypersonic aerodynamic flight.


Is there a special kind of fuel needed to obtain high efficiency engines?

Surprisingly, it isn't a big factor in GA or commercial aviation.

                            Specific  Energy
                            Energy    Density
                            MJ/Kg     MJ/L
Diesel / Fuel oil           48        35.8
LPG (inc Propane / Butane)  46.4      26
Jet fuel (Kerosene)         46        37.4
Gasoline (petrol)           46.4      34.2
HMX (Rocket Fuel)            5.7      10.8

Even high-performance long-range military aircraft like the U2 and SR-71 use some variant of Kerosene with additives, their fuels are optimized for high flash point, not for energy density or for specific energy.

Generally, availability and infrastructure trump efficiency.

Wikipedia: Energy Density
Aircraft Diesel Engine


Would a sharper leading edge increase lift and reduce drag at lower speeds?

The leading edge is round to allow a wider range of angles of attack. If the airfoil is operated at one angle of attack only, the leading edge can be sharp. See the leading edges of compressor blades or fowler flaps for example - the stator rsp. the wing ahead of them directs airflow such that the angle of attack variation on the airfoil is small, in case of flaps especially if the flap has only one extended position.

This means that your sharp leading edge works well because (by chance) it is exactly where the stagnation point in trimmed flight goes. Re-trim the aircraft for a different speed and the right-turning tendency will be reversed. Unfortunately, now you made both sides similar, so you cannot run this test directly.


What is the meaning of nose-art on the Tu-160 bomber?

(wikimedia.org)

Most of the Tu-160 in service are named, much like the B-2 bombers are.

The one in the image is S/N: 7-02 "Василий Решетников / Vasily Reshetnikov" named after a WW2 pilot.

You can find the names of the other ones on the Russian Wikipedia.


What is the approximate accuracy of ASDE-X?

The FAA has a bunch of information on ASDE-X, most of which I personally have no idea how to interpret correctly. The ASDE-X procurement specification in particular has a lot of technical details on radar performance and although I didn't understand much of it I did notice this requirement:

  3.6.3   Map Registration

  The display of target data shall [R306] be registered to the display map with an accuracy of at least 20 feet.

So whatever the technical capabilities of the system are, operationally it seems that you can assume it's accurate to within 20ft, which seems to be reasonable in the context of large aircraft. You may be able to get more out of the documentation than I could, of course.


What is a flying fuselage aircraft (FFA)?

I found this off the website after some searching:

  The advantages of the flying fuselage aircraft (FFA) category,
  compared to conventional aircraft (CA) category and flying body
  aircraft (FBA) category, are the following:

  In conventional aircraft design, the fuselage is aerodynamically
  neutral and joins only the separate parts of the aircraft. As the
  wings grow the buoyancy grows as well. In the flying body aircrafts,
  aerodynamic lift is produced only on the outside of the fuselage and
  the wings, which comprise a unite body. As the fuselage and wings
  grow, the generated lift becomes greater. In the flying fuselage
  aircraft the extra lift is generated from the interior of the fuselage
  and from the whole aircraft in and out. Thus, maximizing the full
  extent of the aerodynamic performance of the aircraft. Practically,
  the new category of the flying fuselage has the following advantages
  compared to the other categories above. i) because of the greater
  generated lift ,the aircraft is designed smaller in size, in order to
  have the same performance as its peers.

  ii) due to the smaller dimensions of the aircraft, it occupies less
  space and needs a smaller hangar. (cost reduction).

  iii) the most important advantage is that during the flight in
  conventional and flying body aircrafts, stability comes only from the
  main wings dihedral, as well as the size of caudal. The flying
  fuselage design acts as a funnel and provides extra stability to the
  aircraft, making the air mass passing through the fuselage in a column
  of air (air shaft). This is maximizing the stability of the aircraft
  in all angles and phases of flight. Source

So what I think what they're trying to say is that the body generates lift as well. It sounds mostly like something like a blended wing body or lifting body in my opinion as a meeting point between a conventional and flying wing aircraft. In any case, the term FFA seems very uncommon and not widely used.

SF-1 http://www.aerosports.gr/images/photos_gallery/archonSF1/4.jpg

The closest similar thing I've found was this aircraft. The F-22 Raptor which it seems to closely mimic is not considered a flying wing nor a blended wing body, and after looking at the fuselage I remained a little unconvinced that it generates substantial lift as a body due to the substantial upper structure and lower structure.


How will the Boom SST not require an afterburner?

1. Will they use variable geometry exhaust?
According to Wikipedia, with references, they plan to use variable inlet/exhaust. So yes, which is similar to the Concorde.
2. Are there other ways?
In theory, the variable cycle engine (VCE), which according to them they won't go for due to the R&D cost. Those engines are also heavy and very noisy, even by the 80's standards.
3. Which turbofan are they going to use?
For the scaled demonstrator they built, they are going for a turbojet, the General Electric CJ610 from the 60's. At the present time, we don't know is the right answer. But the technology can be analyzed.
The inlet of a  supersonic turbojet slows down the oncoming air so it can be compressed and then accelerated by combustion out the back. And as you hinted, a converging nozzle is needed for the supersonic regime. This is the classic accelerate a small amount of air by a lot.
The propeller and the fan (in the turbofan) are the opposite, they accelerate a lot of air by a little. And it's easy to visualize why. The optimum blade tip speed is around Mach 1.0 give or take, so the average velocity of the air behind the fan after gaining energy will not be much faster, but it will be a lot of air (also note, away from the tip it's slower). This is where I don't get it, why have an inlet that slows down the air, only to accelerate it by a little bit, instead of accelerating it by a lot?
They also note that the engine they will settle on will have higher maintenance cost, which hints at running at extreme power levels. This is to be expected as the previous paragraph shows. This answers how the no-reheat. The aim seems to be noise reduction, not economics (wait for it).
Onto some true context:
They compare a fare of \$5,000 to the Concorde's \$20,000 (adjusted for inflation). What they don't say is that the Concorde's original fare was around £1,000, and it only increased because the management realized the rich who flew the Concorde didn't even know how much they were paying.
Adjusted for inflation from 1981, we are looking at an original fare of \$5,500. The reason is simple, to this date, the Concorde's engine remains the most efficient, when you factor in the speed.
Note: I was being very conservative when I said £1,000, in 1980 it was actually £600. And BA was reporting profits on the NYC route.

In short, they already said they can't afford the R&D of the VCE technology, so don't expect something new, it will be present day transonic technology used in the wrong flight regime, which explains the high fare.
Note on the Concorde afterburner:

The reheats are turned off shortly after take off. The reheats are turned back on, for around 10 minutes to push the aircraft through Mach 1 and on to Mach 1.7 where they are no longer required.

Addressing comments:

I would think that higher maintenance costs could be completely attributable to the small market that this engine will have.

If they don't have financing for VCE R&D, then they should settle on an engine with parts commonality to existing models to reduce the maintenance cost.

Existing turbines in reliable daily operation all around the world make enough [thrust] to power the Boom jet.

In the supersonic regime, if they don't use a turbojet or at the very least, a low BPR turbofan, they're wasting fuel, but yes, they will be keeping the noise down. I just didn't like the false marketing of a low-fare. Engine manufacturers would not have been chasing VCE's if medium BPR was the solution all along. The problem with supersonic flight and the low speed of the turbofan exhaust can be understood from this NASA page. The faster the freestream, the faster the exhaust needs to be.


What are the differences between "ground stop", "ground delay", and "gate hold"?

@Pondlife has good quotes and I'll supply some of the direct knowledge he requested.

Ground Stop

Your destination airport cannot accommodate arrivals -- at all.  In this case, they will disallow all planes destined for that airport to take off from wherever they are.

Some examples of what might cause ground stops are:

Weather impacting standard arrival routes, probably more than one.  Aircraft are already in holding patterns and they are running low on altitudes/fixes to put us, and/or those of us in holds are getting close to diverting for fuel.
Airport or runway closure.  If you can't land, you probably shouldn't take off.
All gates are occupied.  If planes cannot depart, there may be nowhere to park arrivals.

You'll note that many times you'll see ground stops described as "Tier 1", "Tier 2".  In short, the T1 ARTCCs are those that directly border with the ARTCC of the destination.  T2 ARTCCs are those bordering the T1 ARTCCs and so on.  Sometimes only T1 departure airports are affected by a ground stop, and sometimes it is everyone.

Ground stops are issued with update times, usually (in my experience) 45-60 minutes later.  They are subject to cancellation at any time, or extension with updated in another 60 minutes.

Ground Delays

These are like the Ground Stops but the airport knows it can accommodate you, just not exactly when you planned to be there.  The reason is most often weather at the destination airport.  Runway closures, accidents, construction, plowing/de-icing can all cause these delays also.

An example

In good weather, airport A may land 90 aircraft per hour.  The helpful airlines have scheduled 110 airplanes to land in one particular hour (no slots at this airport!).  Low clouds and high winds have moved in and now airport A can only land 40 airplanes per hour.  Now of the 110 airplanes, 70 of them will be delayed.  The airlines and ATC will work out which 70 planes those are, and which 40 planes will be allowed in that hour, and start issuing ground delay times.  Of course, these delays spill over into the next hour and cascade.

When a ground delay program is in effect, you will get a "Wheels up time" from ATC, which is when you have to be airborne.  Not sooner, and not much later (3-5 minutes usually).  Getting into your spot in the arrival flow depends on you taking off at this time.  In these scenarios ATC can figure out how/when to get you to your destination, if this isn't the case, that is usually when the Ground Stop program gets started.

Gate Hold Procedure

There is too much happening out on the taxiways, and no room for you.  Stay at the gate!

Reasons for gate holds:

De-icing is in effect and not enough room for everyone to line up at once.
The line to takeoff is too long
Your departure fixes are closed/saturated (This one happens a lot in the NYC Tracon)

In these cases, ATC will issue you a time to start and pushback via clearance delivery (at big airports) or ground control (smaller airports).  Sometimes ramp control can be helpful and help coordinate things... usually not.  When your time is up, you push and taxi and contact ground control.  Not any different than normal except you are given a specific time to do it.


What would reasonably take to get current to fly general aviation aircraft after many years

I am a private pilot and rent old planes, like 73 Cessna 172, with exactly the old instrument panel.
I am a 74 years old retired civil engineer. and fly only VFR.
Here in our airport, Van Nuy, there are many CFI's who would get you up and going in a few hours and will sign you off when you're ready. they charge $30 per hour; and are much younger than our kids.
you would want to look at an airport near an aviation colleges, those kids need hours as CFI. And are very up to date on the latest technologies and what gear is the most reasonable. Like what navigation on which iPad, headsets, what not.