Does/did Russia or the Soviet Union ever fly rocket planes?

Yes
First, we should clarify the fact that a "rocket engine" is a variant of a jet engine. A rocket engine is usually understood as a jet engine that requires external supply of all components of combustion, including the oxidizer.
In a way, that makes things easier, and this is why rocket engines were commonly used at the early stages of jet propulsion development.
Early examples include rocket boosters for traditional piston-driven airplanes. This method is still in use to shorten the take-off distance (down to zero in some cases), but early on it was tried for "regular" emergency power and, of course, research. (Ram jets also had some limited use then).
The first Soviet 100% jet was BI-1 (БИ-1) in early 1942.

wiki Commons
BI-1 had a rocket engine burning kerosene and nitric acid. Even though the airplane was designated as "fighter" and had a space provision for guns, it was really a research ariplane, with the maximum time under power of only a few minutes (it never reached even two minutes in real tests).
The first one was corroded away by the acid. The third one (BI-3) was lost, and the test pilot Bakhchivandzhi died, presumably due to Mach tuck, which was not understood then.
In the later times, during the "true" jet era, there was much less cooperation between the aviation and space industries than in the West. This is one of the reasons why "rocket planes" were a rarity in the USSR, even for research.


Has there ever been a plane with reversed flight controls?

Well into WWII, quite a few French aircraft had the throttle reversed- with full throttle to the rear. The French also customized the imported aircraft in WWII to this effect. From the book American Warplanes of WWII- Fighters, Bombers and Liaison by Col. John. D. Current:

  ... Officially designated Curtiss H75-C1, the aircraft ... had instruments calibrated for the metric system, ... a French style throttle which operated in reverse from U.S. and British aircraft (full throttle was to the rear rather than to the front)...

From joebaugher.com about the same aircraft:

  The Hawk 75A-1 was powered by the Pratt & Whitney R-1830-SC-G engine, with an international rating of 900 hp at 12,000 feet and 950 hp for takeoff.  ... A modified seat was fitted to accommodate the French Lemercier back parachute. The throttle operated in the "French fashion", i.e. in the reverse direction to the throttles of British or US aircraft.

Looks like the French modified the T-28 Trojans too (though I'm not absolutely sure about this):

  ... the French were looking for a replacement for their ground attack T-6s. ... The French did however acquire 148 A models that were in storage at Davis-Montham. They then changed the engines, (removed the R-1300 and installed the R-1820-76A), reversed the throttle operation, (forward is closed aft is open ?? why do this?) ... These planes were then used by the French in Algeria from the end of 1960 until the end of the war in July of 1962.

Not only the French, the Italians and Japanese also used reversed throttles, which caused quite a few problems in service, as the Wikipedia page on Macchi_C.205 notes:

  In the brief German use, Veltros had at least five losses by accidents, often caused by the inverted throttle used on Italian aircraft (In German and Allied fighters the "open throttle" position was forward, not back, and this was the source of several errors).

The Italians too faced problems with this difference in controls. According to Oddone Colonna, an Italian pilot in 150 Gruppo CT at Gruppo Caccia:

  In the summer of 1943 at Vicenza airport I made my first acquaintance with the "Gustavo", a Messerschmitt fighter of the G-6 version. I was among pilots from 23° and 150° Gruppo Caccia to get first flights in the German plane that had been entering service at the Regia Aeronautica for few months.

  We had two main difficulties on test taxing at the Vicentine airport.

  1)    The gas throttle had an inverted movement compared to Italian vehicles. [The Italians like the French used a reversed throttle in their planes. TNi]

  2)    The Plane had hydraulic pedal brakes instead of pneumatic ones with differential command like on other Italian vehicles.


Are the single-engine Piper Malibus required to have a black box?

The short answer is that it probably does not require a "black box".

What you refer to as a "black box" is actually 2 things (and Orange!) a Flight Data Recorder and a Cockpit Voice Recorder. The rules on when they are required is broadly similar, however the data required to be captured by the FDR varies.

For the CVR:

  Fixed-wing aeroplanes with a maximum take-off mass of more than 5 700 kg and for which the certificate of airworthiness is first issued after 1 January 2003 shall be equipped with a CVR with a recording duration of two hours

For the FDR:

  [...] depending on the maximum certificated take-off mass and the date of first issue of the individual certificate of airworthiness. For example, provision 6.3.6 of Annex 6, Vol. I states that, all aeroplanes of a maximum certificated take-off mass of over 5,700 kg for which the individual certificate of airworthiness is first issued after 1 January 2005 shall be equipped with a Type IA FDR

The Piper PA-46 (aka Piper Malibu) has a MTOW ranging from 4,340lb(1,969kg) to 6,000lb(2,721kg).

Speculation about the recent incident, and the specific model intentionally left out!


How is data exchanged between Eurocontrol and FAA?

Flight plans are distributed to all air traffic control units that will be providing services along the route over the Aeronautical Fixed Telecom Network (AFTN).


How to build a 2 mile long runway on a 1 mile square island?

Anyone who has ever flown at Zar (EPZR) in Poland knows how much a runway slope can reduce the needed field length. For aircraft which need a 2 miles long level runway, a 1 mile long one with a 15% slope at its end will do just fine. Make the slope shallow at the bottom and increase it the further up the runway goes, just like the hillside runway at Zar. If the end point is 183.5 m higher than the touch-down point, the height difference is equivalent to a speed reduction from 60 m/s to zero.

Take-offs work in the opposite way, giving the same speed boost on the way down. A 1 mile long runway will do just fine. You do not even need to run it diagonally across the island.

Yes, this does not exactly answer the riddle, but is an engineering solution to a simple problem.


I want to know if other IR devices tend to be as fooled as a missile.

No.

Modern imaging systems are not susceptible to flares in the same fashion as older missile seekers, which is precisely why modern missiles like the ASRAAM and AIM-9X use imaging seekers.

The reason flares worked at all was due to the physical layout of early missile seekers. These used a photocell detector that was sensitive across a wide field of view, on the order of 90 degrees. The trick is how do you use a device that basically provides a "yes, there is something in front of me" to track a target down to the sub-degree precision needed to actually hit it from long range?

The common solution, the "chopper", was to point the photocell forward and place it immediately behind a spinning metal disk with rectangular slices cut out of it following the pattern of slices on a pizza. As the disk rotated, the slices would periodically line up between the target and photocell, causing the photocell to give off a brief flash of power. For instance, if the target was above the missile, the photocell would see it whenever one of the slices was oriented vertically.

The frequency of the pulses was the same as the speed of the disk's rotation. These were sent into a smoother that produced a sine-wave output that peaked, in time, where the target was located. That means that the phase of this output encodes the relative angle between the missile and the target. By comparing this signal to the signal driving the disk motor, the resulting "error signal" directly encodes the direction the missile has to turn.

Early missiles were this simple, feeding the amplified output of the sensor directly into the control surfaces. The resulting flicking motions of the controls became known as "bang-bang". This was extremely inefficient, so a number of additional tricks were used.

The main one was to adjust the motion of the controls by the "angle-off", the angle measured from the missile centerline to the target (as opposed to the angle around the missile body, like a clock). Recall that the slits are rectangular. This means that the amount of time that the signal is present, it's pulse width, is dependant on how far the target is from the center of the disk.

For a target near the center, there is an almost constant signal because the linear motion of the slit is much slower (think of a record turning) and the slits are very close together. In contrast, a target near the outside instead creates very brief flashes at a single time. By subtracting the averaged signal from the raw signal you can determine the angle-off.

So here's why flares were so effective...

For simple bang-bang systems, the flight controls would suddenly start receiving more than one signal. As the aircraft flew away from the flare, the controls would begin flicking back and forth, causing it to track to the center of the two. This not only made it miss the target, but could lead it to run out of energy due to all the drag from the constantly moving controls.

In the case of the more sophisticated sensors, which includes many early missiles like the Sidewinder, flares can be even more effective. That's because when the signal from a target at the center is evened out it goes to zero, so if the missile is tracking properly it has little signal to work with. As the flare moves away, the aircraft's signal remains low but the flare's becomes huge, drawing the missile away from the aircraft. As the missile centers on the flare its signal disappears too, but hopefully after the aircraft has exited the seeker's field of view.

Both concepts only work if the flares move away from the aircraft with some speed - they are generally useless on helicopters for instance. For these types of roles, a new system was created. This normally consisted of an electrically heated block of metal or ceramic, with a series of metal shutters in front of the block. The shutters flicked open and close, producing random flashes of IR on the seeker. This caused the guidance signals to have random peaks, causing the missiles to fly around tracking the phantom signal. Another concept uses a low-power IR laser and a scanner like the ones in a supermarket to cause the beam to periodically pass by the missile, presenting a similar random pattern.

None of these systems work against imaging systems or seekers. For one, they no longer use timing to create the control signal, but instead use a variation of contrast tracking. Hot block decoys image at the same location as the target, so they simply increase the tracking signal, precisely the opposite of what you want. Flares, in theory, can still work, but even trivially simple image recognition systems can measure the size of the IR signals and immediately reject small objects like flares. And with modern processors, one can easily calculate the speed of all of the objects and look for ones that are rapidly slowing down.

Flares still have considerable utility against man-portable and older ground-launched missiles for the simple reason that most of the ones you are likely to meet in the field, including both fSoviet and US models, use some variation of a chopper. You can also release massive numbers of flares and attempt to obscure the target when the missile is far away and it cannot resolve the flares, but that can be accounted for by tracking the release points.

Against a modern missile, flares are generally useless. This has led to the concept of a towed decoy that is essentially a small plane on a wire. These can, theoretically, fool imaging seekers, but I suspect they are not as effective as one would wish. Thus the move to longer and longer-ranged missiles, where the fight really comes down to who has the best radar - which is likely always going to be "the west".

Another approach that is seeing some interest is the use of IR lasers to dazzle the seekers. These generally use UV seekers to look for rocket motors and then scan a laser around that area. If the laser hits the missile it can blind the sensor long enough to escape. I'm not sure if any such system has been deployed.


How do SIGMETs arrive in a cockpit on a modern longhaul flight?

This varies between airlines. In my company (large European Carrier) SIGMETs are uplinked to us via ACARS and then automatically printed on the cockpit printer.

The differences in regions is the format of the SIGMET. In the USA the points of a polygon are mostly described as list of DIR/DIST of VORs (eg 15NM NE STL). Very hard to read if you are unfamiliar with the area. Rest of the world uses coordinates (N3905W09046). Way better to locate on a chart.

There are efforts to automatically download (via satellite) and parse SIGMETs and display them in our electronic charting application in the aircraft EFB. This works currently so-so as there are surprisingly often typos or similar mistakes in a SIGMET text which kills the parser.


Here are the cruise performance tables for the Q400 at the heaviest and lightest weight (click to view larger):
Source: from the Dash-8 Q400 performance manual, which came included with a simulator product I purchased. They probably got their data from a QRH (Quick Reference Handbook), which usually includes such tables in the In-Flight Performance section.
At ISA conditions at FL250, the long range cruise is flown between 209 and 188 KIAS (depending on weight) and the high speed cruise is flown between 230 and 243 KIAS. The corresponding TAS at FL250 (assuming ISA conditions) are:

188 KIAS: 281 KTAS
209 KIAS: 312 KTAS
230 KIAS: 343 KTAS
243 KIAS: 363 KTAS

That last value (for high speed cruise at light weight) seems to agree quite well with the max. cruise speed of 360 KTAS, which one usually find for the Q400. But best range speed at that weight would be around 188 KIAS (281 KTAS), quite a bit slower. At higher weight, the speed differences between best range and high speed cruise are smaller though.
At typical weights the Dash-8 will still be faster than the ATR 72-600. I don't have exact performance tables for that aircraft, but Wikipedia says cruise speed is 280 KTAS. So yes, the Dash-8 is built for higher speed. The biggest difference is the choice of engine: PW150A with 3782 kW for the Dash, but PW127M with only 1846 kW for the ATR, more than a factor two difference! While this difference probably causes a higher best range speed for the Dash compared to the ATR, in absolute fuel usage the ATR is still more economical.


Are jet engines designed in a way to make an explosion result in the least damage possible?

The most (kinetic) energy is in the fan and turbine blades and disc. The engine is enclosed in a containment chamber whose purpose it is to protect the rest of the airplane from shrapnel in case of a fan disc or fan blade failure. Here's a video of a test where a fan blade failure is simulated:

             As you can see, the fan blade more or less completely destroys the engine, but no debris or shrapnel leaves the containment chamber.

Unfortunately, the turbine disc and blades have too much energy to be realistically containable. (In other words: the required shielding would be too thick and heavy.)

Engine failures where debris or shrapnel is able to leave the containment chamber is called an uncontained engine failure, and they are very rare, but they still do happen.

Since it is impossible to contain a turbine blade or disc failure, risks are mitigated in different ways, e.g. by requiring regular, very detailed inspections and extremely tight tolerances.


Can countries introduce new aviation policies unilaterally?

Aircrafts need to be certified to operate under FAA/European/Russian... regulations in terms of safety, noise, etc.
For instance, in Europe EASA is the authority "for the airworthiness and environmental certification of all aeronautical products[..]".

Sometimes countries actually want to introduce new policies.
One of the most famous was in 1971, when "The US, India, and Malaysia all ruled out Concorde supersonic flights over the noise concern[..]" as reported here on Wikipedia.

Another one about aircraft noise was in 1999, when "The EU's proposed noise ordinances effectively prevented the use of hush-kit outfitted aircraft in Europe[..]".

So every country already has its own regulation.


In the US, how does the distinction between E2 and E3/E4 airspace affect pilots?

"Caution: as noted in the links below, in actual practice, the distinction between E2 airspace and E3/E4 ("extension") airspace is often ignored by ATC..."
In the Center environment, we make no distinction between the surface area and the extensions when dealing with SVFR. The reason is simple. I can't clear a SVFR and an IFR in that airspace at the same time (or two SVFR aircraft), so those extensions should be empty if I'm allowing SVFR. Conversely, I'll not allow a SFVR operation (remember, the pilot has to request it), if I have an IFR aircraft cleared in that surface area.
In the case of Class E that's adjacent to Class C or D airspace, the pilot should be talking to ATC, anyway.
Keep in mind, though, if you're just buzzing along VFR and you see that there's a surface area ahead of you, there's nothing wrong with calling Center and asking if there's known traffic there, or even requesting flight following (cheap insurance!) through the area.


What is this military turboprop aircraft?

From that really grainy, blurry picture, it looks like a C130 Hercules.

bulbous fuselage
Straight, ironing board-like wings
High wing configuration
4 turboprop engines
Huge, high empennage
The rear is shaped like it could have a ramp.

If you are sure it was a turboprop, it looks like the C130 is a strong contender.


Does the civil industry use the CAN FD bus?

It's hard to prove a negative, but I would say the answer is no for the following reasons:

In all my years in the avionics industry, I've never heard of anyone
even discussing the possibility (though I realize CAN FD is fairly
recent).
There are numerous manufacturers that use ARINC 825 which is an
adaptation of the basic CAN.
The AEEC has no
active committee working to update ARINC 825 to include support for
CAN FD which would be the normal process before it would be used in
avionics.

Avionics suppliers just can't decide to use a new databus.  Their equipment has to talk to equipment from other manufacturers and if you don't have a defined protocol and agreement between suppliers it just won't work.


What would be the hazard of raising flaps on the ground?

Without knowing what type of aircraft was involved in this incident, it is hard to tell. But, in general, a moving flap would provide a pinch point for any personnel in the area. Considering the article mentions that the hydraulics were in the on position, there would be a possibility of crushing a body part of maintenance personnel.


Can pilots land an aircraft with only the use of throttles?

Not safely, no. According to the Wikipedia article on UA Flight 232, with only throttle control, it is impossible to "control airspeed independent from sink rate", because there's no control of angle of attack.

In 232's case, that meant:

  On final descent, the aircraft was going 220 knots and sinking at 1,850 feet per minute, while a safe landing would require 140 knots and 300 feet per minute

I.e., even going 50% above safe landing speed the descent rate was 6 times too high. This is nowhere near safe, and it was something of a miracle that 185 out of the 296 souls aboard survived.

After that accident, the NTSB decided training for such a case wasn't practical.


What are the takeoff and landing distances of motor gliders?

You may wish to obtain POH data from the 18-21 meter motor gliders you have listed and compare it to your calculated results. Also look into information such as wing loading, aspect ratio, takeoff speed (or stall speed), and airfoil type in addition to power source to include in your report.

Motor gliders, true to their name, should lift off well before 500 meters.  Landing distance would be similar and also available in POH.


It's a more specific designation of the general engine. There are lots of variants of the CFM56 in your case the 5B3/P variant:

  CFM56-5B3/P: Same as CFM56-5B1, except for increased thrust rating and
  redesigned high pressure compressor, high pressure turbine, and low
  pressure turbine.

The type certificate has the specific info for it as well. There is also lost of info on wikipedia under the -5B series section.


How do airports handle traffic during emergencies?

The facility under duress will declare "ATC Zero" and all traffic will be handed off to other controllers while that facility is offline.

In the case of a control tower, this means the airport either acts as a non-towered field or as a closed field (depending on the nature of the emergency).  If it is a TRACON, then the ARTCC will assume control of the TRACONs airpsace.  If it is an ARTCC, that might present bigger problems as continuity of radio communications may be impacted and I'm not sure exactly how this would be handled but assume it would be re-routes around the ARTCC.

I've been inbound to IAH when their tower decided to close (I forget why), and the response was to put everyone inbound to IAH into holds and handle diverts when fuel became an issue.


How many US airports have 4 or more parallel runways?

Based on my current navigation database (AIRAC 1909, valid from 2019-08-15), I found 7 US airports with 4 (or more) parallel runways:

KATL (Hartsfield–Jackson Atlanta International Airport):
5 parallel runways: 08L/26R, 08R/26L, 09L/27R, 09R/27L, 10/28
KDEN (Denver International Airport):
4 parallel runways: 16L/34R, 16R/34L, 17L/35R, 17R/35L
and 2 more parallel runways: 07/25, 08/26
KDFW (Dallas/Fort Worth International Airport):
5 parallel runways: 17L/35R, 17C/35C, 17R/35L, 18L/36R, 18R/36L
and 2 more parallel runways: 13L/31R, 13R/31L
KDTW (Detroit Metropolitan Airport):
4 parallel runways: 03L/21R, 03R/21L, 04L/22R, 04R/22L
and 2 more parallel runways: 09L/27R, 09R/27L
KLAX (Los Angeles International Airport):
4 parallel runways: 06L/24R, 06R/24L, 07L/25R, 07R/25L
KMCO (Orlando International Airport):
4 parallel runways: 17L/35R, 17R/35L, 18L/36R, 18R/36L
KORD (Chicago O'Hare International Airport):
5 parallel runways: 09L/27R, 09R/27L, 10L/28R, 10C/28C, 10R/28L
and 2 more parallel runways: 04L/22R, 04R/22L

I do not know how many are planning additions, but I linked the Wikipedia article for each of the airports, maybe that will help you find more information on that.

Trivia: There are only 3 airports outside the US with 4 parallel runways: LFPG (Paris Charles de Gaulle Airport), LFTM (Istanbul Airport) and ZSPD (Shanghai Pudong International Airport).


Is there any limit on how narrow aisles can be?

For a transport category airplane with 20 or more seats the minimum aisle width is 15 inches from the floor to a height of 25 inches, and 20 inches width above a height of 25 inches.

  §25.815
  Width of aisle.

  The passenger aisle width at any point between seats must equal or exceed the values in the following table:

  1A narrower width not less than 9 inches may be approved when substantiated by tests found necessary by the Administrator.


What was the first jet-powered supersonic aircraft?

One ME-262 Pilot claims to have exceeded Mach 1 in a dive, but the conditions are disputed due to compressibility and later tests that find the aircraft uncontrollable above Mach .84. The first U.S. fighter plane to exceed Mach 1 in level flight is the F-100 Super Sabre.

For research on how the sound barrier was broken as it results to aircraft design is to read Wikipedia: Sound Barrier.

Wikipedia also has a good read on Supersonic Aircraft that lists aircraft by manufacture date.

As for technological innovations, I would suggest reading about the turbofan engine, specifically inlet design since the air must be slowed sub-sonic before entering the compressor stages.


How can I calculate effective wingspan of a high aspect ratio model airplane?

I think the term "effective wingspan" should better be replaced by "effective aspect ratio". There is no change in wingspan when the wing flies closer to the ground, but it behaves like an equivalent one with a higher aspect ratio. The basic formulas can stay unchanged, only aspect ratio should be adjusted.

Think of it this way: If there was an increase in span, would wing area grow with it? Would that mean that wing loading goes down? No, it is better to assume that the wing near to the ground behaves like one of the same area, but of a higher aspect ratio with an increased span and a proportionally shortened chord.

Sighard Hörner gives an approximation on page 7-13 in his book Fluid Dynamic Lift for the increment by which the effective aspect ratio is increased over the geometric aspect ratio:
$$\frac{∆AR}{AR} = 0.09\cdot\frac{h}{b}$$

b is wingspan and h is the height of the aerodynamic center over ground.

He also has graphs for the change in effective aspect ratios of vertical tails with the height at which a horizontal tail is attached, or the effective aspect ratio of a biplane wing:
Plot of effective aspect ratio over geometric aspect ratio of a vertical tail depending on the vertical location of the horizontal tail (picture source)

The case where an effective span makes sense is in the calculation of the induced drag and vortex location of a rounded wingtip. Here is Hörner's list of wingtip shapes from the same book:

Wing-tip shape and tip-vortex location for a family of wings (picture source)

And lastly, no, wingtip vortices don't cause induced drag. It doesn't become true just because it is repeated so often. Please look here or here for a better explanation.


Why do naval jet aircraft need to have strengthened undercarriages?

The landing on carrier is indeed hard. The reason is not the deceleration (which is handled by the hook), but the touch-down. Since the deck is short, the wires can't be spaced very far apart, so the aircraft must touch down very precisely. Since the precision is better at steeper angle, the aircraft landing on carrier do not flare. At all. So they hit the deck at more than twice the vertical speed compared to typical landing on decent runway.


Why are flying-boom tankers restricted to a single boom?

There are several reasons why it is hard to support multiple booms on a single tanker:

1) Booms need an operator who is located in the fuselage. Video systems provide for remote control on newer tankers, but older ones still use direct view or looking straight down the boom at the refueling point in the receiving aircraft.

2) The boom is physically large. Its weight, large diameter and telescoping tube length would be difficult to install on a wing.

3) A wing bounces around a lot more than the fuselage does. Since the boom is rigid, this complicates keeping a good connection.

4) The high flow rate of a boom is only useful for larger aircraft like bombers, which are too big for simultaneous refueling. This somewhat reduces the advantage of having multiple refueling points.

Probe and drogue has a lower flow rate through a lighter, narrower hose. It is passive from the tankers point of view, and it is flexible.


Can fighter jets be reloaded with ammunition mid-flight?

Aerial rearming has been a daydream of military tacticians for decades. However, the task is much more technically demanding than aerial refueling, which is in itself a fairly demanding task for pilot and boom operator just to get a 50-foot fuel hose hooked up.

The technical issues include:

Physically capturing and docking a smaller aircraft with a larger one. The USAF tried it back in the 50s with a B-36 carrying a specially-modified RF-84F. In those days there were no computerized flight controls, and docking the fighter back up with the mothership after it had done its thing proved to be more dangerous to the bomber than just running the mission without a fighter escort at all. It would not be inconceivable for modern avionics to improve on that, however the relative size of fighters compared to larger support craft has increased considerably. Here is a KC-135, built on the "Dash-80" airframe that also sired the 707, refueling an F-15C that's not really that much smaller when you look at it:

Placement of most ordinance under the aircraft. Most fighters and ground attack aircraft carry weapons on external hardpoints under the wings (the RAF-variant SEPECAT Jaguar being a notable example of both overwing pylons and the insanity of British aircraft designers):

When in refueling position under a tanker, the aircraft's most deadly weapons are on the wrong side of the jet to try to get to them to replace or reload them. You'd have to either bring the aircraft inside the mothership, or have it land on top (and provide a sheltered work area for a crew to get to the ordinance pylons).
Relative fuselage width of mothership versus wingspan of fighter. The largest fixed-wing craft in the U.S. arsenal is the C-5 Galaxy. It's a big plane (though not the biggest, that distinction belongs to the Ukrainians with the An-225). Here it is with a couple F-15s and a C-130 parked nearby for scale:

Even with a plane this size, able to transport other planes, you can see from the below photo that neither the F-14 being loaded nor the Galaxy is in a flight-ready condition at the time:

I'd be interested to see whether one of the light weight fighters (F-16, F/A-18) might fit with less disassembly (the F-18 might if you folded the wings), but it remains that you're just not going to be able to fly a modern fighter into another aircraft in midair, at least not with any currently-flying airframe combination.
Getting crew access to the plane. If you've ever seen a ground crew loading a fighter for a mission, you know it's a fairly complex process of not only putting the ordinance (which can weigh up to 2500 pounds for large laser-guided bombs) onto the hardpoints, but wiring up the arming and firing circuits for each one, and programming the plane's FCC with the loadout. This requires getting a lot of people underneath the aircraft (it can take two or three people to load one hardpoint especially if the ordinance has to be muscled into place; here's two people loading probably the lightest piece of external ordinance the USAF has onto an F-15C, and it's only two people because they're using a hydraulic loader):

As the aircraft can't be taken inside the mothership (see previous point), the only other possible place for this to be done is on top of the mothership. That means you'd have a crew out on top of the aircraft muscling ordinance into place. That first requires a sheltered area on top of the mothership that the fighter can be docked and tethered to, as there's no way a crew is getting anything done in a 150-knot headwind. The fuselage vs wingspan difference is important here too; you're not going to be loading AIM-9s onto the wingtips of an F-16 or F-18 when the F-16's wingspan is 33 feet while the cargo deck width (a stand-in for the amount of usable fuselage width) is only 19 feet.

In summary, loading/reloading an aircraft is a serious operation requiring a dozen people to do quickly and efficiently. Putting those dozen people, and their equipment, and all the ordinance into a mothership, getting the fighter to safely approach that mothership and touch down on top of it, then getting the crew into position to remove expended hardpoint pylons and reload new ones, then getting the plane to safely get back off the mothership... It's just not gonna happen with any current technology.

There was a proposed design for a twin-fuselage C-5 as a shuttle transport aircraft; the idea was that this aircraft could be used instead of the risky crane system to pick the shuttle off the ground at an alternate shuttle landing site like Edwards AFB:

An aircraft of this scale might, might, be able to support an aircraft coming in between the tails, docking, then using remote arms to load ordinance. This aircraft would, by wingspan, be the largest plane ever to fly, and would compete closely with the An-225 on every other size stat except total length.


Is it currently possible to build a jet engine with 1,050 kN of thrust? (236,049 lbf)

The limit to the size of turbomachinery is considerably larger than the size of current aero engines.

To estimate how large cores can get, we can look at power plant SCGT. You can get heavy frame turbines as large as 576 MWe for the SGT5 (this is half of a typical nuclear reactor at 1000 MWe). The aeroderivative LM6000 delivers 40 MWe out of a 270 kN turbofan core, and the largest aeroderivative, Industrial Trent 60, provides 60-70 MWe out of a 415 kN thrust turbofan core.

This would suggest an thrust equivalent of 3.5-4 MN or 800,000-900,000 lbf for the SGT5. You can't just fly a frame turbine like this, except in the hold: it's slow to spin up, its speed is on the low side, and it's not certified to aviation standards. But that's just a matter of design. It simply shows the amount of power that can be crammed into a single turbine core.

So, could we make a 1 MN engine? Yes, we are making cores with several times the power. Could we make an airworthy 1 MN engine? With effort, perhaps, of course it would cost money to develop. Would it be as good as the engines we have? That's the million dollar question. Or it would be, and more of a billion dollar one, if there were a market for it.


What is the purpose of the three cylinders under the engines of the Junkers 52?

The three cylinders hanging below each engine are the oil coolers - this page has a much closer shot which I've reproduced below.

Oil enters and exits the cooler through the two vertical lines and swirls around the hollow air channels. The cold air in flight moving through the tubes cools the oil, which is then returned to the engine.

Courtesy of eBay, here's a photo of an old, rusted-out cooler where you can clearly see the air channel tubes inside. (Using an oil cooler in this condition would promptly empty the engine of oil...)


Can Private Pilot training, funded by employer, count as company hours?

No law against this. Nor is there any restriction on who pays for your flight training. You are referencing something which applies to your privileges as a student pilot. You may not act as Pilot In Command (PIC) for compensation or hire, nor carry passengers or cargo for compensation or hire - see §61.89. Having an employer pay for your flight training cannot be viewed this way. Again, these regulations are only applicable to time as PIC, so, as a student, this would be only solo flight time.
Now, if the employer attempts to have you perform flight duties in the furtherance of their business while you are a student pilot, i.e. they asked you to ferry an airplane for them somewhere, or perform some other task which is not related to your flight training, that does violate the law. However, the employer only paying for you to undergo flight training is not a violation of federal law.


How does altimeter reading vary when departing from ISA conditions?

We set it to less than 1013 → it will indicate more than 0'

Above statement is incorrect for all scenarios.

(Source)

Remember, the anticlockwise rotation of the knob to set lower than 1013 also corresponds to anticlockwise rotation of the altimeter hands.

(Source)

Above image is what you're after.

Above the transition altitude (varies by location) you set standard setting regardless of the ISA deviation.

Below the transition altitude (TA) or when descending through the transition level (TL), you set whatever the ATC advises. From a pilot's perspective, it's that simple.

Unless you will be performing an approach in a cold area (usually below 0°C/32°F), then special altimetry equipment may be required. Requirements will be noted on the approach plate.

Related:

Wikipedia: Flight level
Skybrary: Altimeter Temperature Error Correction
How is non-standard OAT accounted for?


What is the date of first use of the TAF format?

For the current format, it was 1993 when it was standardized.

On July 1, 1993, a new, revised Terminal Aerodrome Forecast (TAF) format and code replaced the existing TAF code. This new code is in effect in most countries. The exceptions are the United States and Canada. These two countries issue Terminal Forecasts for domestic use and TAFs for the military and those airports serving international aviation.
On January 1, 1996 the U.S. and Canada will convert entirely to the new TAF code. After that date, the new code for weather reports (METAR) and TAFs will be used worldwide. The North American code used in the FT (and SAO) will be discontinued. Although the new TAF code is being adopted worldwide, each country is allowed to make modifications or exceptions to the code for use in each particular country. The TAF code, as described here, is the one used in the United States for those airports serving international aviation and will also be used after the January 1, 1996 conversion date. The World Meteorological Organization's (WMO) publication No. 782 "Aerodrome Reports and Forecasts" contains the base METAR and TAF code as adopted by the WMO member countries. (Source)

noaa.gov also confirms the date for the US.
The WMO publication No. 782 can be found here.


What steps are needed to communicate with ATC on an A320?

You need to even realize that you have to push a button to talk. Not everyone grew up with ham radio, CB radio, or walkie-talkies, especially nowadays where everybody has a mobile phone.
You need to find the PTT button.
You need to select where you want your headset to be routed: you can talk to your co-pilot, you can talk to ground crew, you can talk to the cabin crew, or you can talk to you radios.
Note the plural above: the plane has multiple radios. You need to select the right one.
You need to know the frequency of the ATC entity you want to talk to.
You need to tune the radio (the right radio) to that frequency.
Every radio has an active frequency and a standby frequency. You need to make sure that you change the right one. (Either change the active one, or if you change the standby one, you need to make that one active.)
You need to realize that radio is a shared medium, and that only one person can talk at any one time, and that you need to wait for a break.
Depending on how busy the frequency is, you might not even recognize where the pauses are, or you might not be able to squeeze yourself in because you are not used to talking that fast and efficient.

I consider myself technically adept, and I used to do a little bit of CB radioing in my youth, but I'm not sure if I could figure all that out in 20 minutes.


Under what circumstances can the Initial Climb Area extend more than 2 nautical miles?

The definitive reference for this stuff is the TERPS, and it says that the ICA can extend to 10NM(!). See 14-1-6(b):

  Length. The ICA length is normally 2 NM, measured from the ICAB to the
  ICAE along RCL extended. It may be less than 2 NM in length for early
  turns by publishing a climb gradient. The ICA may be extended beyond 2
  NM to maximum length of 10 NM. A specified altitude (typically 400
  feet above DER) or the interception of PCG route must identify the
  ICAE.

I may have missed it, but I didn't see anything in the TERPS that explains how to set the length. However, the ICA definition from the IPH says (emphasis mine):

  Initial Climb Area (ICA). An area beginning at the departure end of
  runway (DER) to provide unrestricted climb to at least 400 feet above
  DER elevation.

I couldn't find a formal definition of "unrestricted" but in ATC-speak it usually means "go for it" (e.g. ATC Orders 4-3-2(e)(1)). In this context, though, I think it means "no lower limit" rather than "no upper limit". In other words, the ICA will be extended to allow for 'worst case' scenarios where an aircraft's climb rate is extremely limited.

That suggests hot and high airports, and if you look at the ODPs for a famously high airport like Lake County (Leadville), CO (KLXV) at 9,934' MSL you'll see that the departure procedures are indeed almost straight, e.g.
DAVVY ONE, which is more or less straight out for 20NM from runway 34.


What is the lifespan of an airline engine?

In general, the engine life is measured in terms of two things:

Flight hours
Flight cycles

A takeoff and a landing counts as a flight cycle.

The most important concept in engine life is the Time Between Overhaul(TBO), which is basically the manufacturer recommended time period after which the engine is stripped down,checked thoroughly and required parts replaced. After overhaul, the engine is usually cleared till the next TBO.

An overhauled engine is theoretically as good as a new one and comes with the same life (TBO) and warranty, if applicable. Airline engines (for example the Rolls Royce Trent series) usually have TBOs of over 15000 hours. The record for maximum time for an engine on wing (i.e. use in aircraft before removal for overhaul) is well over 40,000 hours.

The life of an engine is given by the manufacturer and are different for different engines. However, the engine life depends on a number of parameters and is usually different for various engine components.

The rotating components have life limits which are less than the engine and are replaced periodically, mostly during the TBO.
For example, the turbine blades are replaced after a set number of turbine cycles and/or after a set number of hours, which are lesser than the others.
In addition, most rotating components (compressors, turbines) are periodically subjected to checks, and are replaced if found damaged.
In case of abnormal operations, some parts are required to be replaced. For example, if one engine is required to give excessive thrust (for example in case of One Engine Inoperative), the engine is subjected to thorough checks similar to TBO.

Airline engines are usually serviced (Overhauled at TBOs) and maintained till they are deemed not good to use or not economical to (service/repair and) operate anymore.

Most of the engine manufacturers employ condition based health monitoring programs, which helps them to plan when to service and repair the engine. As a result, the engine life varies based on its condition.


Why does the 737NG EGT drop during take-off?

Above is takeoff engine data$^1$ and is indicative of the behavior you've mentioned. (FF is fuel flow and TLA is thrust lever angle.) The same behavior can be seen here as well:

A 737-800 takeoff video
An "EICAS cam" video for what I think is a 777
An Embraer E190-E2 video

(The exact timing may depend on how long the engines are left in the stabilization process.)

Note: The 737NG EGT sensors are at the T495 station in the low pressure turbine section. There are 9 thermocouple probes and their average is displayed.

The CFM56 employs variable stator vanes (VSV) in the compressor. In general those vanes close at low engine speed and open at high engine speed (shown below).

  Source: CFM56-5A manual

The specifics are proprietary, but plausible conclusions can be made. When the engines are stabilized for TO/GA, it could be the ECU (electronic control unit) opening the VSV to provide the ideal compressed air for faster engine acceleration (more air before the fuel would lower the EGT).

Note: The VSV is controlled by the hydromechanical unit (HMU), which receives input (torque motor current) from the ECU (CFM presentation, PDF page 16).

Of course if you have cause for concern, don't use the internet for flight, and check with your airline.

$^1$ Lion Air Max crash report (sadly the only public source of FDR data I can think of is accident reports).


How is it safe and legal to land in parallel runways

Whether Parallel Runway Operations are allowed at an airport is dependent on many factors, such as:

Proximity of runways to each other
Availability of precision approach systems for each runway

There is two modes that are interesting here, which is the full parallel mode, where lateral separation is no longer required once both aircraft are established in the precision approach and staggered mode, where the runways are too close for parallel mode and need to maintain 2.5 NM lateral separation during the approach phase.

The same regulations apply to departures, you can read about it in EUROCONTROL's SkyBrary.

Related questions:
How are go-arounds safe with parallel runways?


What factors influence the maximum speed of an airship?

I'll do this without most of the math since your target audience won't want to read equations in your story.

In the simplest terms, the maximum speed of an airship occurs when the maximum thrust generated by its engines is equal to the drag it experiences while being pushed through the air at that speed. That drag depends on the diameter and length of the airship (more specifically, the projected frontal area and the total "wetted area" of the entire vehicle's outer skin).

This is a complicated business because the relationships between all of those variables are strongly nonlinear- for example, the drag varies with the speed squared and the power required at a given speed varies with the cube of the speed.

So in your story: doubling the power of the engines will increase the airship speed only slightly, at the cost of doubling the fuel burn rate and therefore the fuel tank capacity- and thereby reducing the useful payload.

Similarly, doubling the length of the airship will roughly double the wetted-area drag, which means you have to double the horsepower of the engines or their number in order to achieve the same maximum airspeed as the shorter airship.


Do I need a license to flight test a homebuilt seaplane at very low altitude?

14 CFR §1.1 defines an aircraft as “means a device that is used or intended to be used for flight in the air.”  Flying boats are intended for flight in the air.  Therefore.....


Is it possible to calculate lateral acceleration from pitch/yaw/roll rates?

No. Yaw, pitch and roll rates only describe the change in the orientation or attitude of the object relative to a frame of reference. Is it changing orientation to point further clockwise? or counter clockwise, or upwards/downwards, etc.

Any acceleration is a measure of the change in the velocity of the object relative to the frame of reference in question. An object can be rotating to change it's orientation or attitude in any way completely independently of it's velocity through that frame of reference or how that velocity might be changing.


Could turbine or compressor stages of a jet engine be switched off to improve fuel efficiency?

You cannot "switch off" a stage of a turbine engine.

As seen elsewhere jet engines are a single block mechanically locked together: all the stages (compressor AND turbine) connected to the same shaft. If the shaft turns, all connected stages turn with it.

You can have designs with multiple shafts, but this increases the complexity (design and maintenance) heavily.

Even if we assume for a moment that you could have 1 shaft per stage, stopping one of these would be generally a bad idea.
For acoustic reasons the number of blades on the stationary part of the stage and those on the rotary part must be prime to each other (example: 37 blades on the stationary side and 39 on the rotary one); this means that when the rotary part stops you cannot align all the blades with the stationary ones, creating drag and losses within the engine, thus reducing the efficiency.

  How would efficiency of a Jet Engine change, if we assume for a second that its a possibility, to stop a few stages(turn them into free instead of locked)?

You would still decrease the efficiency: compressor stages are the ones actually pulling the aircraft forward (you would then produce less thrust*) and the turbine stages are the ones extracting energy from the exahust.

*: you could even risk having the flame going upstream if you stop too many compressor stages and not having enough pressure at the combustion chamber inlet.


Do vertical stabilizers create vortices like wingtips do?

In general, the vertical stabilizer and rudder create a symmetric airfoil. As there is no pressure difference between the two surfaces of the vertical stabilizer, vortices doesn't form, unlike the wing, which is designed to produce lift at normal angles of attack (it is usually cambered, producing lift at zero angle of attack).
You're correct that the vortices are generated due to the movement of rudder. Usually, vertical stabilizer doesn't create vortices unless rudder is deflected.
Note: Though I can't be sure, I think the F-22 is braking (the F-22 does not have a dedicated surface for braking like F-15 and uses the normal flight control surfaces). A similar thing happens in the following figure

Source: f-16.net
Only one F-22 (second from top) is using its control surfaces, probably for braking, resulting in vortices from the vertical stabilizer.


How should I decide whether to pursue an EASA ATPL or an FAA ATPL?

Both the EASA and FAA ATPL programs are good, I know people who have both and their view is that neither has an intrinsic benefit over the other. The EASA one has more theory in it which most of the ATPLs I know think is worthless, however if you know how to study it's really not that bad.

The question of which is best for you is who you want to fly for and where their airplanes are registered, as it's the country of registration which defines which ATPL you need, not the location the airplane is in. An FAA ATPL will let you fly US registered (N Register) airplanes anywhere in the world, and an EASA one will let you fly an EASA member's airplane, so most of Europe anywhere in the world. If you want to fly for a US airline you need an FAA one, if you want to fly for a european airline you need an EASA one.


What is the purpose of this interesting pattern of class E airspace in northwest Alaska?

This is easier to explain in reverse: rather than why there is so much class G airspace there, why is there so much class E airspace  everywhere else?

Remember, all airspace is class G unless it has been designated something higher. Wind your clock back to the early days of aviation, and the entire country was class G!

However, that isn't very safe, particularly in bad weather. Pilots were getting lost and running into each other.

So we got navaids and radios, and narrow strips of airspace along between navaids became controlled airways, i.e. class E. If you scroll over to Canada in SkyVector, you can see what this probably looked like.

Fast forward several decades, and there are now so many airways criss-crossing the US that they've merged into one big class E blanket, so it's easy to forget how we got here.

But there are still a few areas where the airway density never quite reached full saturation, mostly in mountainous terrain (of which Alaska has a lot), and those pockets still remain class G--and reveal the past.

As to why the V airway in your example has a different floor than the T airways, I'd assume that comes down to the minimum VOR reception altitude due to the terrain. Other than the floor, though, it's the same.


What´s the logic behind the Power Curve?

why does power affect airplane´s aerodynamics?

It doesn't. The aerodynamics will determine how much excess power is left for acceleration or climb. But not the other way around.

Why is it important how much power […] the engine has?

Because the power of a piston engine is constant for the same air density, regardless of speed. It is more helpful to give a power rating because that figure is valid over the whole speed range, unlike thrust. Thrust is inversely proportional to speed and so a thrust figure is only valid for exactly one operating point.
Pure turbojets have approximately constant thrust at subsonic speed, so here the thrust rating is more useful. The power a turbojet can produce increases with flight speed.


Purpose of CHT drop in piston engine shutdown procedures?

According to this document, this is to allow the engine to cool and level the oil temperature:

  CHT Drop- Wait two minutes or until you can clearly see the H on Cyl Hd
  Temp. This is to allow the engine to cool and level the oil
  temperature. Closing down too early may damage the engine.

This is most probably to prevent damage to the engine due to shock cooling. Any rapid decrease in temperature during shutdown can cause damage to cylinder heads However, note that this theory is quite controversial. This is discussed in detail here and here. Especially, as @Lnafziger points out in his answer,

  ... in fact the engine cools much more quickly when you shut it down at the end of a flight.


How do I calculate the landing distance in a landing chart with tailwind?

You can’t use that chart with tailwinds - not without an expansion of the graph to include that information.  Without more information from the OEM on landing distance in a tailwind I would not risk my life on a calculation derived from that chart.


Where can I find registration information of a private aircraft registered in Germany?

I don't think the information is accessible on a public website.

According to the German wikipedia the Luftfahrtbundesamt (LBA, the German Civil Aviation Authorities) cannot publish the information for data protection law reasons.

On their website (in German) they state that they do release information to members of the public at a fee (they love that here).

A little bit of link-clicking later you will find that you have to pay 40 euros. I am not sure whether they can release the name of the owner.

The law (Luftverkehrsgesetz) governing the information in the register can be found here.


How many warning signals are voiced in modern airliners?

Modern airliners have voice warnings in a number of systems like,

Ground Proximity Warning System
Terrain Collision Avoidance System
Windshear Alerts
Radio Altitude callouts
Trim
Fire Detection
Autopilot configuration
Pressurization systems
Landing gear system
Stall/overspeed warning.

The amount of voice warnings vary from aircraft to aircraft. For example, airliners.net has the following list of voice warnings in Bombardier CRJ-200 (other than GPWS and TCAS):

  "APU" APU overspeed or overtemp

  "Door" open or unsafe passenger door indication

  "Jetpipe Overheat" overheat indication in jetpipe/pylon

  "Smoke" smoke detected in cargo area of lavatory

  "Config Autopilot/Flaps/Spoilers/Trim/Brakes" Aircraft not properly
  configured for takeoff

  "Wing Overheat" Overheat in fuselage wing anti-ice ducts

  "Anti-ice Duct" Bleed air leak in fuselage or wing anti-ice ducts

  "Bleed Air Duct" leak in different part of bleed air duct system

  "Brakes" brake overheat

  "Config Brakes" here again because it's for having the parking brake set
  while airborne

  "Gear Disagree" disagreement between gear indications and handle position

  "Gear Bay Overheat" overheat in main gear bay

  "Nose Door" Nose gear door open after gear fully extended and locked or >250
  knots

  "Engine Oil" oil pressure <25 psi

Initially, most of the voice warnings were recorded voices. However, more and more modern systems (like in newer 737s) are using computer generated voices.


What was the flight route from New York to Paris that Air France took in 1955?

The route was IdleWild (renamed JFK in 1963) or LaGuardia -> Gander, Canada -> Shannon, Ireland -> Paris. The trip took a total of about 18 hours going eastbound with tailwinds, and 24 hours going westbound with headwinds.

Gander was opened in 1938 and continues to be the preferred refuelling stop for aircraft that can't make the hop across the north Atlantic in one go, simply because it is the northeasternmost point on the North American continent where such a facility could be built. For a while it was the largest airport in the world, and was used extensively by the military during WW2 as a stopover point for aircraft being ferried to Europe.

Air France used the route from the beginning of their transatlantic service in 1946 until the late 1950's, when the jet age made it possible to fly the route non-stop.


Why is wave drag non-zero for a flow without shockwaves?

The drag can be computed from Navier-Stokes momentum equations as:

$$D=-\oint_{S_\infty}p\hat{i}\cdot d\vec{S} - \oint_{S_\infty}\rho (\hat{i}\cdot\vec{u})(\vec{u}\cdot d\vec{S})$$

Usually, all boundaries other than the rear boundary (Trefftz plane) would have the same flow properties as the free-stream, and they fall out of the integral. We are left with:

$$D=\int_{S_T}{\rho u(V_\infty-u)dS}$$

As you correctly pointed out, the momentum defect of a potential flow should be exactly zero, which means that drag should also be zero.

However, for oblique shock in small-disturbance potential flow, the oblique shock (or rather, each constant potential wave characteristic) extends to infinity, carrying energy with it. If you want to calculate the far-field drag, you would need to do the integral around the entire far-field. This is different from energy dissipation in viscous boundary layer or subsonic normal shock.

Picture ref. https://nikander.github.io/compflow/Anderson/Chapter4/print/


Is the FlightGear sim accurate in 2018, specifically Cessna 172 aircraft?

It completely comes down to what you want to train in the sim. I have used FlightGear in my beginnings of when I started my interest into aviation. I guess you are using the default C172. What you can do in this sim is learning to navigate, use the instruments (at least the ones that are modelled to work correctly) and maybe learn checklists. But that's it actually.

If you really want to train for a real Cessna 172 aircraft, I can highly recommend getting Prepar3D and the C172 by A2ASimulations. It's one of the best flight simulation addons in the flight sim industry at this time. A full simulation of everything from oil viscosity to water contamination of fuel. Even a real C172 walk-around is implemented (with fuel inspection, tire inspection, everything) and a full damage model. You have to treat it like in real life to not damage parts. And you can also install a GTN750, GTN650 or GNS systems in her, if you own one of that beauties in real life. Also study level of course.

What you can't train in flight sims, however, is the hand flying.

I own all those addons and can't stop recommending it.


ETOPS between Johannesburg, South Africa, and Perth, Australia

ETOPS originally was an acronym for Extended Twin Operations. While it has been changed to just Extended Operations, the focus is still on twin engine aircraft. South African Airways currently operates the route with an A340-300, which has four engines. If it has an engine failure, it is not as much of an emergency as in a twin-engine aircraft, so it does not necessarily have to adhere to the same ETOPS rules for alternates.

Johannesburg to Perth is certainly a fairly remote route. But at least eastbound it's less than 10 hours, and, for example, the A350 is certified for 370 minute ETOPS. This is 6 hours, and while that is at a one-engine cruise speed, it's still fairly close to covering the entire route.

Looking at the Great Circle Mapper, a 240 minute ETOPS would be enough to fly the route with only a slight diversion from being direct. This is with 300kt diversion groundspeed. From the map, it appears that Mauritius and Cocos Island could serve as alternate towards the middle.


How much testing to commerical aircraft manufacturers typically do on each new plane after it rolls off the production line?

Testing is performed for specific reasons.  As you noted testing for certification and testing production aircraft are not the same.

Testing for certification is to establish that the design of the aircraft meets airworthiness standards. A guide is available in the form of AC 25-7C.

Testing production aircraft is primarily a quality control issue and serves to prove that the aircraft is built to the drawings -- that it complies with the approved design.  It's only a small part of the process and is discussed in section 2.7 of AC 21-43A.

As noted, in the AC a flight test is required (with one exception). Production testing will evolve over time as there is a constant effort to 1. ensure adequate test coverage to avoid quality 'escapes' and 2. to do it as efficiently as possible to minimize costs.

One other test that is typically performed is an acceptance test. This is not regulatory. It is contractual and is performed with the participation of the customer.  Airlines won't accept delivery of an aircraft until they're satisfied it meets everything they're paying for. A friend of mine who worked for an airline's engineering group said it was about a 4 or 5 day process to checkout and accept delivery of a plane.


How does ATC know if you have been assigned a squawk or not?

Let's remember what a transponder code is used for in the first place.

When transmitting a non-discrete code, such as 1200, ATC has no way1 of telling you apart from other aircraft transmitting the same code. On the ATC radar, you will simply show up as something like "1200/A030" where 1200 is the code transmitted and A030 (3000FT) is you mode C altitude.
To provide you with radar service, ATC has to be able to identify you on the radar, which means that they have to be able to distinctly associate your flight with a specific track on the radar. They do this using transponder codes2. An assigned (discrete) transponder code will be unique for a flight within a given area. Say you are instructed to squawk 2174, you will now show up on the screen as "2174/A030", and because ATC knows that you, and no one else in the area, is squawking 2174, they know that they are you looking at you.

Your question is, how does ATC keep track of the assigned transponder codes? Today this is mostly an automated process. A central flight data processing system (or the US equivalent - sorry for my European terminology) contains a database of all active flightplans as well as their assigned transponder codes. When a discrete transponder code is received by the ATM system, it will automatically query this database, asking for any flightplan information associated with this specific transponder code. It will then show the received information on the radar screen. Essentially, the transponder code is a database key, allowing the system to look up information about your flight and show it to the controller.

Now you are no longer shown on the radar with just your transponder code and mode C altitude, because the system has a lot more information about you. You might be shown as something like "N12345/A030/C172" (callsign/altitude/aircraft type). The exact label varies greatly from system to system - the point here being that the system is now able to show specific information from your flightplan rather than just generic information submitted by your transponder.

So how does a controller know if you have been assigned a transponder code or not? If you have, you will be shown on their radar screen as a full label, with callsign etc. If not, your callsign is no where to be found on the radar, and they will have to guess that you are probably one of the (potentially many) 1200-tracks on the screen.

1: They can in fact identify you by other means, such as requesting your exact position and heading, but identification with the help of transponder is a lot simpler.

2: Normal 4-digit transponder codes are slowly being replaced by mode-S transponders, which transmit a unique 24-bit aircraft identifier at all times to the radar system. But that's probably best left for another question.


Are tower simulators used in civil ATC training?

Absolutely (and not just civil ATC training - military as well). A large part of modern ATC training is simulator training. This is true for all types of ATC - area control, approach and aerodrome (tower).

For area and approach, the simulator is fairly simple, since the essential bit is a radar screen and a screen with flight information. For tower, there is the visual aspect as well, which makes tower simulators quite large and complex. Some tower sims are relatively simple - 4 big TV-screens with a 3D model of the airport, and a couple of computer screens with radar and other equipment. There are also full size, 360 degree sims, where the "windows" are created by an array of projectors or large screens. After working traffic in one of those for a few minutes, you start to forget that you're not in a real tower.

During simulator training, students can run scenarios in the simulator that are either based on generic airports or real airports. The traffic levels and situations can be tailored to match the expected learning curve of ATC students. This makes simulator training a great tool for both initial and recurrent training of air traffic controllers. Much like pilots, after getting our license, we have to go back to the sim once a year to practise unusual situations, emergencies and so on.

For every controller position in the simulator, there are 2-3 connected "blip driver" positions, from where the aircraft movements are controlled. The controller in the simulator will talk to the blip drivers via "radio", and the blip drivers will respond as pilots and provide the necessary input to make the planes move around accordingly.


How to calculate normal takeoff ground roll when the POH only has Short Field Takeoff tables?

In the C172S POH I have, it's on p. ii (Performance - Specifications): 960ft ground roll and 1630ft total over a 50ft obstacle. The note on p. iii says:

  The above performance figures are based on airplane weights at 2550
  pounds, standard atmospheric conditions, level, hard-surfaced dry
  runways and no wind. They are calculated values derived from flight
  tests conducted by Cessna Aircraft Company under carefully documented
  conditions and will vary with individual airplanes and numerous
  factors affecting flight performance.

In other words, it's a useful number to know but you're unlikely to get exactly that performance unless you're a Cessna test pilot in a brand new aircraft. If you own the aircraft (or rent it often) you might want to spend some time actually measuring takeoff distances yourself, to see what performance you're really getting.


If the number of flights in the world exceed 2^24 how will ICAO allocate the address to the flights?

Addresses are assigned to suitable equipped aircraft, not to flights. The total of 16 777 214 available adresses is distributed in blocks that are assigned to individual states. Block size depends on the size of the states, e.g. the US and Russian Federation have block with 1048576 addresses, while e.g. Grenada or Mauritius only have blocks of 1024 addresses.

The allocation of addresses is decribed in ICAO Annex 10, Vol. III, Chapter 9.

An extract of the relevant part can be found here.

As long as the addresses are just assigned to conventional Mode-S transponder equipped aircraft there should be sufficient free addresses. This could change if all airspace users would be assigned a unique address, e.g all drones participating in future UTM (urban or unmanned traffic management).


How does SLATS/FLAPS retraction damage the RTLU mechanical stop if we retract them after the ADIRS are set off?

According to this PPRuNe thread, the problem is not the retraction of the slats/flaps but instead turning the ADIRS (air data inertial reference units) off. The RTLU is designed to operate in a feedback loop, where its position is controlled based on input from the FACS (Flight Augmentation Computers, which take input from the ADIRS). If the ADIRS go offline while the slats are extended, the RTLU goes into a "emergency return to low speed" mode. This allows maximum rudder travel by driving the RTLU to mechanical stops. If this happens regularly it can cause damage to the stops.

This appears to be related to the Indonesia AirAsia Flight 8501 crash. Although this issue was not one of the main contrbuting factors, the report lists this as one of the Technical Followups (TFUs) that Airbus issued as a result of the investigation. It improves the reliability of the RLTU, the failure of which was cited by the investigation.

See this related question for more on the function of the RTLU in the flight control system: What are the “channels” on the A320 Rudder Travel Limit Unit?


Airports are responsible for bird control and should provide adequate wildlife control measures. Some major airports are provided with an ornithological department that has ravens or similar birds trained to drive away other birds from the airport premises.

However, this is not a 100% efficient solution and flight crews have procedures that must follow if birds are reported.

If large birds or flocks of birds are reported or observed near the runway, the flight crew should consider:

Delaying the takeoff or landing when fuel permits. Advise the tower and wait for airport action before continuing.
Take off or land on another runway that is free of bird activity, if available.

To prevent or reduce the consequences of a bird strike, the flight crew should:

Discuss bird strikes during takeoff and approach briefings when operating at airports with known or suspected bird activity.
Be extremely vigilant if birds are reported on final approach. If birds are expected on final approach, plan additional landing distance to account for the possibility of no thrust reverser use if a bird strike occurs.

References: http://www.birdstrike.org
http://www.boeing.com/commercial/aeromagazine/articles/2011_q3/4/


Is there any certification for Aircraft Security that Software Engineers can accomplish?

I am unaware of any individual certifications for engineers related to avionics - security or general SW development. Caveat: This is based on my experience. That's 24 years of civil avionics development which followed a USAF career in R&D, mostly space systems. I'm an aero engineer by schooling and my work is primarily defined as 'systems engineering' and management.

Fundamentally avionics development is no different than any other product development. We define and develop hardware and software to perform specific functions on aircraft. The skills are essentially the same as the auto industry and even some consumer products. For the software side, this means real-time embedded applications -- not PC, web, or client/server apps.

The biggest differences to other markets is the level of regulation and the life span of the products. Everything we build has to be certificated as part of an aircraft under a Type Certificate (TC) or Supplemental Type Certificate (STC) or as an 'appliance' under a Technical Standard Order (TSO). And even then the TSO'd product installation has to then be certificated under the aircraft's TC or STC. Because of the regulations, change is expensive so the products tend to have a very long life span. There are updates along the way, but you very seldom see wholesale product redesigns until the product is almost unsupportable or there are changes in the regulations.

Certification is about demonstrating that the product complies with the rules. In the US, that's Title 14 Code of Federal Regulations. That means focusing the entire business to meet the rules. That includes internal development processes and procedures and a quality program that's compliant.

Industry standards such as SAE, RTCA, (and EUROCAE in Europe) are the basis for most of these internal procedures. RTCA DO-178C doesn't tell you how to write code. It sets a standard for a SW development process that will produce the necessary artifacts for certification and theoretically result in SW that meets the necessary level of safety and design integrity. The company has an internally defined software development process that is compliant with DO-178.

As for security, RTCA DO-326A, Airworthiness Security Process Specification provides guidance. It doesn't tell you how to build a secure system. It defines a process that will allow you to identify the security risks and ensure that you address the risks.

So what's the best way to learn the avionics business? Seek employment with an avionics company. Avionics is a niche business. There's no big educational pipeline to feed the industry. If you have the fundamental engineering skills and a willingness to learn, you can get a job in avionics. That was the basic criteria I applied when I was a hiring manager at my last employer.

As to the basic skills; For a SW engineer I would look for SW design and coding experience. Real-time embedded experience is a definite plus but not a deal breaker depending on the specific job. Most companies I'm familiar with use ADA, C, C++, etc. Getting familiar with the industry standards helps (and shows initiative) but it won't make you an expert.


That is exactly how balloons “steer” - they pick an altitude where the winds aloft are going the way the pilot wants to - assuming winds at an available altitude exist where the wind is what the pilot wants.

Many balloonists use Ryan Carlton’s wind tool found here to get a good idea of local winds: http://ryancarlton.com

NOAA has a website called RUC soundings that presents actual wind and temperature aloft data from balloon launch sites and then interpolates for locations in between: https://rucsoundings.noaa.gov/

While the pilot can plan a flight and do amazingly well to get near to where they wanted to go, at the end of the day, a balloon, as an unpowered aircraft, is at the mercy of the winds.


Under what conditions is a flight attendant required on an aircraft?

14 CFR Part § 121.391.

It depends on the size/weight of the airplane and how many passengers it can hold

  Except as specified in § 121.393 and § 121.394, each certificate
  holder must provide at least the following flight attendants on board
  each passenger-carrying airplane when passengers are on board:

  For airplanes having a maximum payload capacity of more than 7,500 pounds
  and having a seating capacity of more than 9 but less than 51
  passengers—one flight attendant.
  For airplanes having a maximum
  payload capacity of 7,500 pounds or less and having a seating capacity
  of more than 19 but less than 51 passengers—one flight attendant.
  For airplanes having a seating capacity of more than 50 but less than
  101 passengers—two flight attendants.
  For airplanes having a seating capacity of more than 100 passengers—two flight
  attendants plus one additional flight attendant for each unit (or part of a unit)
  of 50 passenger seats above a seating capacity of 100 passengers.

http://www.gpo.gov/fdsys/pkg/CFR-2011-title14-vol3/pdf/CFR-2011-title14-vol3-sec121-391.pdf

Parts § 121.393,394 relax these requirements when a plane stops, but denotes how close by the flight attendants must be, and other things like exit door requirements.

Remember, Flight Attendants are there for your safety :) which is the motivation for these regulations.

[Edit]
14 CFR Part 91.533 covers flights operated under "Part 91" regulations:

§ 91.533 Flight attendant requirements.

  No person may operate an airplane unless at least the following number of flight attendants are on board the airplane:

  For airplanes having more than 19 but less than 51 passengers on board, one flight attendant.
  For airplanes having more than 50 but less than 101 passengers on board, two flight attendants.
  For airplanes having more than 100 passengers on board, two flight attendants plus one additional flight attendant for each unit (or part
  of a unit) of 50 passengers above 100.

  No person may serve as a flight attendant on an airplane when required by paragraph (a) of this section unless that person has
  demonstrated to the pilot in command familiarity with the necessary
  functions to be performed in an emergency or a situation requiring
  emergency evacuation and is capable of using the emergency equipment
  installed on that airplane.

It looks like the "training" to act as a Part 91 Flight Attendant is just showing the pilot they are capable.

The big difference between Part 121 and Part 91, is number of seats (potential capacity) vs. people actually on board.  This is interesting in light of the recent 787 Boeing Business Jet deliveries (http://boeing.mediaroom.com/2014-02-05-Boeing-Business-Jets-Delivers-First-Two-BBJ-787-8s-of-2014).  So if it was just the owner and the pilot crew, there wouldn't need to be a flight attendant (assuming, of course, they're operating under Part 91), even though it is a huge plane.


The United States Marine Corps is facing a dilemma. There are not enough combat ready fighter jets for their pilots around the world. Boeing's answer to this problem is the C+ Program. The program will take 30 retired F/A-18C Hornets and upgrade them to the most state-of-the-art platform, creating the F/A-18C+. (boeing.com, 2016, emphasis added)

Three years after that Boeing article, only three upgrades were completed. Given the slow pace, that's enough time for isolated airframes to be spotted as they're readied for transport and upgrades. The initial volume of 30 was reduced to 25 then 19, enough for one squadron (seapowermagazine.org, 2019). The photo above ticks all the boxes: the missing and covered nose radome, covered canopy, and missing wings.


what is the statistical risk of head rotor failure?

I worked medium and heavy transport helos in the Marines, and I never heard of an incident caused by a rotor head failure. Blades, transmissions, all kinds of other things, sure, but not main rotor heads.


Can an aircraft be docked at the gate from the right seat?

The system you showed may actually be the type that does not depend on the position on the pilot. Edit: The version you have works with a Moiré pattern, and is indeed dependent on which pilot is looking at it.

I dug into the AIS Netherlands information for our country's biggest airport Schiphol (EHAM/AMS). They have a few different systems; the one you link seems to be a lot like the SAFE DOCK system, which uses a Laser Range Finder (LRF) system to identify the position of the aircraft

  Due to the digital display presentation, both pilots get the correct alignment information as well as the closing-rate and stop information.

I'm guessing that this system will become more common to allow for more flexible crew tasks during taxi. Furthermore, this system can detect obstacles, and as such provides extra safety.

The two other systems on EHAM do depend on the seating of the pilot. The effect of the wrong pilot parking the plane is very simple: your plane will be parked off-center with a deviation exactly equal to the spacing between the pilots: your plane will end up such that the co-pilot is sitting where the captain should be. The fact that the AIS does not quote any procedures for this says it all: you just shouldn't do it and wake the captain for a minute to do his duties.

Of course, there are procedures for when the system is not available (emphasis mine):

  The system is operated by an employee of a handling company, who also keeps a safety watch during the docking. The pilot of an arriving aircraft has to be sure that the system is activated. If not, pilots should not enter the aircraft stand and stop before the red boundary line, until the system is activated or a marshaller has signalled clearance to proceed.

The logical conclusion we can draw here is that, if the systems are not available (or, in the case of the question, if the captain is fast asleep), a marshaller will guide the plane in - either way, a marshaller will stand by to oversee the docking and make sure the SAFE DOCK system is living up to its name.

As @reirab helpfully pointed out, the marshaller's job may be nothing more than a simple clearance to enter the gate and let the pilots do their job; they should be perfectly capable of parking an aircraft without the displays. In the aviation world, it's perfectly acceptable to spend a lot of money on these things if they can increase safety; if only due to reduced workload for the pilots.


Did WW2 airplanes ever jettison their empty external fuel tanks to act as weapons?

Yes, and not even empty tanks. It didn’t always work, but it’s happened:
     This is how American pilots used drop tanks as bombs during WWII.
Fun fact, cellulose drop tanks were developed to save metal during the war! The article references P-47s, but I would not be surprised if P-51s did the same.


Why does the glideslope use UHF when the localiser uses VHF band?

The higher the frequency the smaller the transmitter, so fitting the G/S on a small tower near the touchdown zone becomes practical. Compared to the large LOC array at the other end of the runway.

  [Of] the advantages of using UHF frequencies for glideslope operation is only a small antenna and ground plane is required. As a rule of thumb, the higher the frequency, the smaller the antenna can to be (avionicslist.com).

Here is a table for the localizer and glide slope frequency pairing (fcc.gov).

As for why not UHF for the LOC, my understanding is the range. A pilot can receive the LOC farther out than the G/S (8 miles more).


Original answer: The speed of Category A aircraft is too low to execute the missed approach.  For this particular airport, it's basically a hole in the ground with steep mountains on all sides. To go missed, you gotta get up in a hurry, and the TERPS data probably indicates a minimum speed is needed.

Edit:  Despite the downvotes and comments stating that my answer was "unlikely", I'm sticking to my guns.

To make sure that I knew what I was talking about, I contacted the FAA's Flight Procedures Standards Branch in OK City and eventually was put in contact with someone who was able to pull up the documentation on this approach.

Listed in the comments of the document he was looking at was this: "Ref 8260.52 CAT A -- final approach speed is too slow for RNP missed approach segment length for obstacle penetration."

Translation: whoever put this approach together did the math that is required, and the formula result was that speeds needed for obstacle clearance are not sufficient when using CAT A speeds.

Note 1: some math and formulas required to build an IAP missed approach procedure can be found in Chapter 4 of 8260.52. (https://www.faa.gov/documentLibrary/media/Order/ND/8260_52.pdf)

Note 2: 8260.52 has since been superseded by 8260.58, which itself has undergone an update and the most current document is 8260.58A.

Gory technical details (or some insight as to why this oddity is the way it is):

The thing that makes this approach special is that not only is it a RNP AR approach, the missed approach requires abnormally precise navigation as well (i.e. RNP values <1.0).  The length of this span of the missed approach (from the MAP to TIPOC) is bounded by the results of formula 4-3-8 in 8260.58A, which is dependent on the true airspeed of the slowest aircraft of the approach.

DMASRNP is the max distance allowed for a given true airspeed (category) to return to RNP 1.0 on missed approach. The longer the distance to return to RNP 1.0, the faster the plane needs to be.

In the case of the KGUC RNAV (RNP) 6 -- the MAP to TIPOC span is 6.7NM along track, which is longer than the formula's results no matter which of the three possible RNPs are applied if you are using a category A airspeed (these results are applied to the whole span as per figure 4-3-5).

Why this formula is needed, and applied to the whole span for that matter, is a mystery, though -- 8260.58A gives no design rationale for this limitation, or why it is pegged to airspeed.  A rationale is that navigation errors are cumulative though -- the slower you're flying, the more time you have to drift off course before you make it to the next "gate" where a higher RNP prevails.

Other approaches (even in similar terrain and with seemingly similar conditions charted) may not have this peculiar limitation, though -- the KRIL RNAV (RNP) Z 26 approach, for instance, also requires RNP < 1.0 on the missed approach, but for a shorter distance -- a mere 3.5NM from the MAP to TEROE, whereas the limit distance for Category A given the RNPs used in the missed approach there is 4NM.

Moral of the story: pay attention to your approach plates!


The two main purposes of an aviation headset are making the cabin quieter, and making it easier to talk to ATC while keeping your hands free, so in selecting a headset you want to find one that will do both of those things very well.

To figure that out there are three major things you'll want to look at when picking a headset:

Noise Reduction Rating (NRR)
This value, expressed in decibels (dB), indicates how good the headset is at preventing cabin noise from reaching your ears.  A higher noise reduction rating cuts out more engine and wind noise (which prevents hearing damage and noise fatigue) and makes it easier to hear radio calls.
Higher values are better - a headset with a 30dB NRR is quieter than one with a 24dB NRR.

  Noise reduction ratings may be expressed as a positive or negative number (it's attenuation, so negative is "more correct"). 24dB or -24dB means the same thing when reading specs.

Headset Style
There are three basic styles of headsets, and one type will probably most comfortable for you.
Earcup headsets have earcups that surrond your ear, like classic David Clarks.
In-Ear headsets have earbuds/eartips that fit into your ear canal.
Over-the-Ear headsets are like headphones and sit "over" your ear (mainly for quiet cockpits).

Weight
Self-Explanatory: You're going to have this thing on your head for the duration of your flight. Wearing a 20-ounce (0.6 kg) headset is more fatiguing than a 10-ounce (0.3 kg) one, and you might have some neck pain if the headset is too heavy.

  Earcup headsets tend to be the heaviest - 12 to 24 ounces. Over-the-Ear headsets usually weigh in at 3-4 ounces, and in-ear headsets are generally 3 ounces or less.

Secondary things to consider include:

Do you prefer Active or Passive noise reduction?
Active Noise Reduction can make a very light headset extremely quiet, but requires power (battery or ships power) and cost a bit more.
What accessory functions would you like?
There are headsets with Bluetooth, headsets with music inputs, etc.

Ultimately the best way to pick a headset is to try several to see which you like best. You're evaluating them on some objective things ("How quiet is it?") but also a lot of personal/subjective things: "Is it too heavy?", "Do the earcups/eartips fit my ear well?", "Is the clamping force like having my head in a vise?", etc.

Your flight school may sell headsets, in which case ask to try a few different ones on your next few lessons to see which you like best. You can also chat with other pilots and try to get a ride with them to try out their headset (the exception to this often being in-ear headsets -- some folks get grossed out at the idea of having someone else's ear gunk on their tips).


Is it possible for an airliner to cruise at engine full thrust?

Full take-off thrust time is limited by the engine producer: bad things like overheating and meltdowns may happen. If you mean set the thrust to maximum allowable cruise setting: nothing much would happen other than consuming a lot more fuel than when using optimum cruise setting: fly fast enough, and the drag rises a lot without icrease in lift, due to compressibility effect. So the aircraft does not need to fly higher when going faster, it only burns more fuel.


I know nothing of X-plane, but I fly gliders in real life and often land in fields and "uncharted" airports.  Uncharted does not mean the airport does not exist. However, you do need some idea of where it is, GPS coordinates, or some fix from a known point.  Even a general description of its location can get you close enough to find it.  I have often used "Google Earth" to pinpoint a potential landing area and once I find it there, I have what I need to navigate to it.  I check the date of the GE photography some are several years old and things could have changed that make the field unsuitable.
GE also has tools that you can use to measure the length and width of the "runway" and its orientation.  I look for obstacles that might interfere with my approach.  I also check to see if it is fenced because that can complicate getting my glider out of the field.


Tapered Wing Providing low Coefficient of Lift

By tapering the wing you have in effect a 3D case even if the wing is sitting between wind tunnel walls. Lift varies along span almost as if the wing would be in free flight with twice the span and the long chord at the root. Since tip chord is only a quarter of root chord, that full wing would have 0.075 m² area with 0.5 m span, giving it an aspect ratio of 3.33. Below is a figure from Sighard Hoerner's book Fluid Dynamic Lift (Chapter 3, Figure 4) which shows how the local lift coefficient varies over span for wings of different taper ratio. Your wing in free flight would be ¾ between the second and third from the left.

A 2D case is only possible with constant chord as all of the wing would produce the same circulation (lift times chord). With the varying chord along span only the shorter end will reach the maximum lift coefficient of 2.3 locally, but at a lower angle of attack. You still get more lift with your wind tunnel walls than in free flight, but with a taper ratio of 0.25 not much of the 2D case is maintained.

The higher circulation of the long chord end produces extra circulation on the short chord end and lets it stall at a lower angle of attack when the root has only reached half of its full potential (see figure above where center lift coefficient is only half of the tip lift coefficient). The reduction in maximum angle of attack from -13° for the 2D case to -10° also shows how much potential lift is lost.


Why doesn't the A320 pack flow indicate HI as it should?

From FCOM §Air Conditioning - Controls and Indicators:

  The pack flow indication can be up to 30% below the actual flow rate.

That's why the needle may not be at the HI position. LO to HI is 80-120%, with normal being 100%.

The aforementioned needle (YouTube).

The sensor responsible for sending this data is the delta P (differential pressure) sensor at the inlet of the FCV (flow control valve). My guess is that it is not designed for a precise reading, but only an indicative reading.


Why don't airlines load their passengers like freight?

Boarding takes a long time, true. There are more efficient strategies (.pdf) which have been proven to speed up boarding by between 20% and 50%, still they are not adopted. Why?

You need to load the baggage, too. Also the catering. And fuel. You need to inspect the aircraft, run through checklists and brief the new crew. This all takes up time, too. Airlines do not see a big saving by loading passengers faster, and then waiting for all other jobs to be completed.

Your radical idea of containerizing passenger transport would certainly speed up things, but it would cost a lot of payload.

The most efficient pressure vessel is a sphere, and the next efficient is a cylinder with spherical ends. Pressurizing a boxy container is structurally very inefficient.
Loading passengers on palettes first and sliding those palettes through a narrow opening takes time in itself. And the palettes have their own weight, their own floor, their own support structure for the baggage racks, their own cabeling for the entertainment system. They would, however, not need their independent pressurization, so their weight impact would be moderate.
A possible "flatbed" airliner which could attain the shortest boarding times has only half as much fuselage height (or less) to transmit bending loads along its length. See here for an example of buckling in a fuselage skin due to bending loads. Now consider that reducing height by 50% will need four times more cross section in the longerons to keep stiffness constant. That will make the fuselage much heavier.

In the end, airlines go with the solution which maximizes their profits. By using a hollow cylinder and let their "cargo" self-load, they can maximize their payload and get tolerable boarding times. Tolerable for them, that is. That better loading procedures could allow you to come to the airport later is of no interest to them. If they would see an advantage in shorter boarding times, there would be ample of opportunity by improving strategies, even with existing airplane designs.


How are the "medical communication" headset sockets on some airliners used?

I'm going to assume you're talking about something like this:

Photo liberally stolen from here.

As other have mentioned, these are generally connections for a standard aviation headset (headphone and microphone plugs). When plugged in you're typically connected to the cockpit (so the pilots know what's going on), and on commercial airlines you may also be patched in to a medical consulting service via radio.

The principle behind this is similar to the early paramedic programs in the United States: Personnel with some basic training (like flight attendants) are connected to a doctor. They describe the patient's condition and symptoms, and the doctor advises on a course of treatment, which can begin immediately and hopefully give the patient a better chance of survival.

The radio patch can also be used by a doctor onboard the aircraft to consult with other physicians and to help the flight crew arrange for appropriate transport services to meet the plane when it lands.


According to airships.net, LZ-129 Hindenburg had a dead weight of 118,000 kg and carried 58,880 kg of fuel. So that comes to 176,880 kg. Here are the full details:

Actual payload from a Hindenburg flight across the South Atlantic using hydrogen; table from airships.net


How does bleed air maintain pressure for pressurization after being cooled?

That's one of the reasons why bleed air is compressed again before cooling.

  In Air Cycle Machines, high-pressure bleed air from the engines is first passed through a compressor, further squeezing the already hot gas. It is then routed through a heat exchanger or two to remove heat. The now cooler but still highly compressed air then passes through an expansion chamber into a larger chamber. The combined effects of driving the turbine and expanding into a larger chamber dramatically cools the air (usually down close freezing; water traps are critical in the system to prevent freeze-up). (Source)

Simple diagram:

(Source)

The outflow valve is what regulates the pressure, it makes sure the right amount of air leaves the cabin.

  The automatic controller normally maintains the proper cabin pressure altitude by constantly adjusting the outflow valve position so that the cabin altitude is as low as practical without exceeding the maximum pressure differential limit on the fuselage.


Can you file a flight plan to an airport whose runway is NOTAMed closed?

With the added info in the comment, I'm going to say that it should be okay.

  IFR. Runway is notamed closed until 1900L(our ops don't allow landing on taxiways if there are other options and grass is no good for a jet). Airport authority has said it will likely be open much earlier. Wanting to take off and hopefully it will be open by the time we get there.

My reasoning is: you can file to airport (A) that has an instrument approach that will get you down below the weather (say a 3000' overcast), fly the approach until you're in VMC, cancel IFR, and proceed VFR to airport (B), which is where you actually intend to land (but which has no instrument approach to get you below the weather -- and no radar coverage).  This plan works even if airport (A) couldn't accommodate your aircraft for some reason -- runway closed/shortened, weight bearing capacity, whatever.  (Obviously you'd need alternate plans if the weather didn't cooperate with going VFR from A to B, but let's assume that you have a place to go land and plenty of gas to get there for a case like that.)  What matters is that you have an approach you can fly at Airport A, not that you can actually land there.

Worst case, perhaps you could file to airport A where you want to land, and then after that file routing to airport B which is where you'll go if the runway doesn't open up in time.  Thus your filed flightplan is simply "I'll fly an approach at A then go land at B" and that's a perfectly workable plan even with the NOTAM as written.  Then, in flight, if the runway opens early as expected, you tell ATC to amend your destination to airport A and you're all set.

Disclaimer, IANAL (I am not a lawyer), but this seems entirely workable to me.  I know in the 121 world, we explicitly ARE allowed to file to an airport below our mins, with the hope that it comes up (better than forecast) above mins by the time we get there.  It requires extra alternates and such, but just because we "won't" be able to land there based on things as we see them at this moment doesn't mean we can't be dispatched to go there.  And if things get better (weather comes up better than forecast, runway reopens sooner than NOTAM'd), you get to do what you'd hoped for all along.  Just have a sound plan for what you'll do in the scenario where things don't.


What's the point of writing on a cockpit window?

If you use a grease pencil, it rubs off easily from glass

So you can save paper, not have to look down or hunt for the info, it won't fall on the floor, and if it's written in the center of the windshield, both pilots can see it