Finding Angle of Attack/Angle of Sideslip using East/North/Up Coordinates

What you've proposed is a reference frame translation of the aircraft velocity, so instead of the velocity referenced to East, North, and Up (ENU), it's referenced to the direction the aircraft is pointing.  That gives you components of aircraft velocity along the nose, across the wing, and towards the ground. (You can find more details on these conversions by Robert Stengel).  It seems like using velocity across the wing and along the nose you should be able to figure out sideslip, but this approximation only holds in situations where wind is much smaller than true airspeed.

You're assuming here that the motion of the aircraft relative to earth equals its motion through the air.  That means your equations may give an unusual angle of attack when there's simply an unusual vertical wind component, or may report the drift angle as the sideslip where there is no sideslip.  This assumption of zero wind may be valid for rough approximations or in cases of severely limited sensor suites like a low-cost UAV.  This approximation is especially good at high true airspeed, low wind, or if you only care about AOA and AOS derivatives (e.g. for yaw damper control).  However there are some cases where this approximation clearly isn't reliable:

Windshear can result in a dramatically higher angle of attack than expected
Gliders use warm rising air to ascend without the loss of energy that would be anticipated if you're looking at only velocity and pitch
Horizontal surface winds in many places are over 30 kts, and can be much more in the jet stream. (see a wind map for examples).  Many aircraft can land in over 10 knot crosswind component, which your formulas would estimate as a ~10 degree sideslip.

Non-negligible wind is the reason that other methods of estimating AOA are used in practice, such as model-based angle of attack using inertial measurements (sometimes called synthetic air data) is sometimes used instead.  This is the reverse of what you typically do in an aerodynamics course- instead of using known angle of attack and airspeed to find normal and longitudinal acceleration, you're using known accelerations to find angle of attack and airspeed. Ardupilot has an option to do this based on this paper by Joseph E. Zeis, Jr. Another potential alternative implemented by Tor A. Johansen, et al, in addition to inertial measurements, uses airspeed during turns to estimate the constant wind.

Keep in mind there aren't a lot of cheap AOA sensors for a reason besides manufacturing costs: angle of attack is important, but has limits on its practical applications as AOA cannot be considered in a vacuum.  It's usually more important to know your airspeed or acceleration. For example, at high speed if you attempt a high AOA maneuver, the aircraft will rapidly decelerate, and you'd have to lower the nose to prevent the AOA from going into a stall condition. Other limitations are described here.


Does a RC glider always loop when launched?

No, it doesn't loop when launched correctly.
If you launch it so fast that lift is greater than weight, if will pitch up, and may either stall (as happened to me with my foam plane) or may enter a phugoid cycle where it climbs, dives, climbs again, and so on.
But if you launch it at the right speed and right angle (usually slightly down) it will fly smoothly to a gentle touchdown far away. This is the"trim speed" John K was talking about.
By angle I mean direction of flight, not pitch angle, or angle of attack. A stable glider will correct these as a rule.
But if your launch leaves too little lift, it will pitch down. This usually results in an immediate crash, due to the small altitude budget available.
The more lift your elevator is trimmed to create, the higher the optimum speed will be
But it must always have lower angle of attack than the wing, or the plane will be unstable or will nosedive and crash
I often threw my plane at the ground as hard as I could, just to watch it nearly crash, and then zoom up to twice my height.


What is a flameout and how does it occur?

Flameout basically means that the flame in the combustion chamber has been extinguished. A jet engine compresses air, then adds fuel and ignites it. So, it needs three things to function correctly- fuel, air (oxygen), and the heat to make them burn. Removing any of the three can cause a flameout.

It can happen for a number of reasons:

fuel starvation- Air Canada Flight 143 suffered flameout (due to wrong amount of fuel being put) and had to be landed like a glider.
Compressor stall (or surge)- The disruption of airflow due to compressor stall can cause an engine flameout.
Ingestion of foreign objects - British Airways Flight 9 suffered flameouts in all four engines due to ingestion of volcanic ash
Firing of armament- Early in its service A-10 Warthog suffered flameouts due to the engines ingesting the gassed generated while firing the GAU-8 Avenger.

Early jet engines (like the Jumo 004B) had high rates of flameout; however, modern jet engine flame outs are very rare, at the rate of about one every 100,000 non military flights. In most cases of flameout, the engines are restarted for resumption of flight.

Airspace magazine mentions a case where flameout happened because a F-100 ingested fuel (during aerial refueling); however, such occurrences are quite rare.


Should people flying UAVs be called "Operators" or "Pilots"?

The oxford dictionary defines pilot as:

  A person who operates the flying controls of an aircraft

So, technically, the drone operator should be called a pilot.

FAA National Policy Order 8130.34C Airworthiness Certification of Unmanned Aircraft Systems and Optionally Piloted Aircraft Section 6 specifically calls the person operating the UAS (only if it has been issued with an airworthiness certificate ) Pilot.:

  UA Pilots and Observers.

  a. PIC Roles and Responsibilities.

  (1) The PIC must perform crew duties for only one UA at a time.

  (2) All UA flight operations must have a designated PIC. The PIC has responsibility over each flight conducted and is accountable for the UA flight operation.

  (3) The PIC is responsible for the safety of the UA as well as persons and property along the UA flight path. This includes, but is not limited to, collision avoidance and the safety of persons and property in the air and on the ground.

  (4) The PIC must avoid densely populated areas and congested airways in accordance with § 91.319.

The order requires the PIC to have a minimum of FAA PPL:

  b. UA PIC Certification and Ratings Requirements.

  (1) The PIC must hold and be in possession of, at a minimum, an FAA private pilot certificate, with either an airplane, rotorcraft, or powered-lift category; with single- or multiengine class ratings, appropriate to the type of UA being operated.

  (2) The PIC must have and be in possession of a valid second-class (or higher) airman medical certificate issued under 14 CFR part 67, Medical Standards and Certification.

UK CAA also talks about 'Pilot Qualifications required to operate Unmanned Aircraft'. ICAO also uses the term 'pilot' for people controlling an UAV.

Both USAF and RAF call the UAV operators pilots- RAF calls them Remotely Piloted Aircraft System Pilots and USAF, Remotely Piloted Aircraft Pilots and they do get the 'wings'

"United States Air Force Unmanned Aircraft Operator Badge" by SSgt Austin May of the USAF - http://www.af.mil/news/story.asp?id=123170151http://www.mildenhall.af.mil/news/story.asp?id=123170577. Licensed under Public Domain via Commons.

However, there has been no UAV pilot license issued as far as I know.


Does ELMS inhibit cabin pressure alarms on the 777, and would the MEC Override Vent be stuck open following an electrical failure?

Generally, the post you quote from does not look like a credible source. For starters, it says things like:

Electrical failure shut down the Air System Cabin Pressurization Controller (ASCPC) and Air Cycle Machine (ACM) which on a Boeing 777 are all electric. Unlike most other airliners the B777 does not use engine bleed air.

This is completely wrong. The 777 uses engine (or APU) bleed air to operate the PACKs. The author might have mixed this up with the 787, which uses electrically powered compressors for cabin pressurization instead of bleed air.

Bleed air can be supplied by the engines, APU, or a ground air source.
Bleed air is used for:

air conditioning
pressurization [...]

(Boeing 777 FCOM 2.40.1 - Air Systems - Bleed Air System Description)

The vent in the electronics bay exists and it will indeed open automatically to vent out smoke:

The forward system reconfigures automatically to an override mode when:

[...] smoke is detected in the forward equipment cooling system or the forward equipment ventilation system [...]

In the override mode when the FWD CARGO FIRE ARM switch is not ARMED, the vent valve opens, both supply fans shut down,
and the forward cargo heat valve closes. [...] Cabin differential pressure draws air through the flight deck panels into
the E & E equipment compartment to create a reverse flow of air across the equipment, then through the override valve
to an overboard vent.

(Boeing 777 FCOM 2.20.12 - Air Systems - Air Conditioning System Description)
With an electrical failure it is plausible that this valve could no longer close, therefore preventing cabin pressurization.

The ELMS (Electrical Load Management System) described in the post will shed loads in this order:

The load shedding is galleys first, the utility busses. Utility busses are followed by individual equipment items powered by the main AC busses.

(Boeing 777 FCOM 6.20.1 - Electrical - System Description)
The FCOM indeed does not specify the order of these "individual equipment items". Since we don't know what exact failures occurred on MH370, it is impossible to say which systems were shut down. However, during normal operation there are two AC busses (left and right) powered individually. No single point of failure could shut down both PACKs.
The post further claims that

Cabin pressure alarms in the cockpit also lose power.

This cannot be related to the ELMS, which only controls the AC power distribution. The EICAS alerts are however powered by the DC system (via the flight instrument busses), which can be powered independently of the AC busses in standby operation:

The main DC electrical system uses four transformer-rectifier units (TRUs) to produce DC power. The TRUs are powered by the AC transfer busses. [...]
The standby electrical system can supply AC and DC power to selected flight instruments, communications and navigation systems, and the flight control
system, if there are primary electrical power system failures.
The standby electrical system consists of:

the main battery
the standby inverter
the RAT generator and its associated generator control units
the C1 and C2 TRUs.

(Boeing 777 FCOM 6.20.13 - Electrical - System Description)
The author of the post further claims that no warning is given to the pilots because the SMOKE / FUMES REMOVAL checklist in the QRH (linked in the post) shows UNANNUNCIATED. This is however the wrong checklist for the case described earlier. The unannunciated here means that this checklist is for when the pilots recognize smoke or fumes in the flight deck before any annunciation. The correct checklist for the open vent in the electronics bay is this one (and it is annunciated on the EICAS):

[] EQUIP COOLING OVRD
Condition: The equipment cooling system is in override mode.

Wait 2 minutes. This allows time for any smoke in
the system to clear.
EQUIP COOLING switch . . . . . . . . Off, then AUTO
The EQUIP COOLING OVRD message blanks.
Wait 1 minute. This allows time for the system to reset.
Choose one:

EQUIP COOLING OVRD stays blank: ■ ■ ■ ■
EQUIP COOLING OVRD shows again:
Note: After 30 minutes of operation at low altitude and low cabin differential pressure, electronic equipment and displays may fail.

(Boeing 777 QRH 2.19)

Another weird claim from the post is:

The brand new Boeing 777X model suffers the same vulnerability.

I wonder how the author wants to know this. The 777X is not in service yet and the author claims to be an aviation enthusiast from New Zealand. Only a Boeing engineer could possibly know about such system details of the 777X.


Is it possible to fly a large aircraft inverted?

In the movie Flight (2012), Captain Whittaker (Denzel Washington) does not explain why he deliberately inverted his aircraft, but the obvious inference is: since the horizontal stabilizer has slipped off its jackscrew and become jammed into a descent angle beyond the authority of the elevators to correct, in inverted flight this would push the nose far above the horizon and result in either a climb or a stall.

In this attitude, Whittaker would have been pulling back on the yoke to prevent the stall.  In the movie, this worked.  The aircraft was still not under control, but was no longer diving and overspeeding.  Suddenly rolling the aircraft upright in the last seconds before contact with terrain is the unrealistic part.  A hot fighter jet might accomplish this but the roll rate of a passenger jet is too slow.

The movie's flight emergency is based mostly on the crash of Alaska Airlines flight 261 on January 31, 2000.  In that incident, the pilots experienced a jammed horizontal stabilizer with uncontrollable dive, and inverted their MD-80 to arrest their descent.  Unfortunately in real life neither flying officer was stuffed to the gills with booze and coke: the maneouver failed and the aircraft crashed with no survivors.


Is there any way to reduce the noise and vibration in a C-130 Hercules?

Active vibration control systems exist for some aircraft, though I doubt an ex-military type would have anything off the shelf. There is a system from Lord (the engine mount people) that is intended to counter the vibration from a helicopter main rotor to improve passenger comfort, among other things. This is their claimed reduction:

AVCS Product Brochure

They focus on helicopters but sell components as well, and may be able to customize something that could work for you.


Does the landing distance required for a wet runway needs to be within a certain range of the landing distance available?

Short Answer = Yes.

Long Answer = landing within 70% of the LDA rule is a HARD limitation. The runway's length does not change with the weather, so the 70% cannot be changed. But, of course, your A/C landing distance does change with weather. Thus, your 115% landing distance required must still be within the 70% LDA.

in practical application, not every landing you do will use 70% of the LDA, or even close to it (It's only a limitation, right?). In many cases, There's still lots of room for your 115% LDR to land safely within the 70% LDA.

Hope this helps!


Are airliners searched after each flight?

At the end of the Airplane's day (It's last flight for the day) It's the mechanics and the cleaners' turn to be on the plane.

The mechanics start out by performing the daily check or overnight check, it's like a routine checklist to make sure that your airplane is well maintained and ready for another day of flying. They also look at the Cabin Log books of the aircraft for any maintenance issue the flight crew has encountered during the day.

These issues could be anything:
ex:

"Seat at Row 28 won't recline properly"

or

"Sink is clogged"

and while the mechanics are resolving those cabin issues along with their daily checks, the cleaners also start their work. Cleaning all the seats, galleys and lavatories. They are not particularly looking for bombs, but they make sure to report any lost items they've found during cleaning.

Almost the whole cabin is cleaned up and inspected. So if anything is left, it will be found. Even the life jackets underneath your seats are accounted for, so if anyone decided to leave something under there, the mechanics would spot it.


Why have cargo hybrid airships not succeeded in the market?

First of all, there is the question of demand. There aren't enough cases where a very heavy load needs to be moved to a remote location by air. There are probably even fewer where there are funds to actually pay for this option. The An-225 is currently the largest aircraft in operation, and it was only constructed under special circumstances. Although has certainly found use, they still haven't even found the funds to finish a second one which is partially built.

When this option is needed today, helicopters are deployed on cargo aircraft to the area. The helicopters may have to make multiple trips but can do the job. So the subset of cases is even smaller; where heavy cargo needs to be delivered to a remote area and also cannot be split into shipments that helicopters can handle. Deploying a large airship in this manner is also much harder. Either the airship would have to fly itself there, which could take a long time, or it would have to be reduced to a transportable size.

The airship would also need to be protected from the weather somehow. This could require either a very large (and expensive) hangar. Without a hangar, the airship must be tethered, and restraining such a large surface area in the wind would be difficult.

Wind would also affect operation of the airship. Helicopters are of course limited by weather conditions, but wind would have a much greater effect on a large and slow airship.

If the airship could be fairly easily collapsible, it would solve the issues of storage and transportation. However, this is not a simple problem to solve. This would require a large development budget. If you are comparing this to the cost of the 787 development, where are you going to find buyers for 1000 of these airships in order to break even and make them affordable?

The issue is that there needs to be a market for this kind of transportation, which currently competes at least partially with existing helicopters. Why invest in a new type of vehicle when the current option works fine for most cases?


What vertical flight profile could be expected from an aircraft if the pilots were incapacitated?

Emergency descent (like during a decompression event where you need to get from cruise to 10k ft ASAP to make sure the people in the back survive) shouldn't make a nice curve. It only wastes time you don't really have.

Normal operation means the pilot activates the autopilot during cruise which will fly the programmed course set by the pilot. It will stay follow that course (or put itself in a holding pattern on the final fix) until it runs out of fuel or the pilot intervenes when it is cleared for descent. This happened with Helios Airways Air flight 522; both pilots were incapacitated shortly after ascent and the plane put itself in a hold and crashed when it ran out of fuel after more than an hour.

A plane where there is nothing controlling the altitude (when control is lost due to loss of hydraulics for example) will follow a phugoid cycle. That is a series of dives and climbs as the elevators gain and lose bite on the air with speed.


How are airliners AoA-Sensors calibrated?

During development testing the airplane has a "test boom" which in additional to pitot and static inputs has traditionally used mechanical vanes driving pots or resolvers to measure pitch and yaw in the free stream.  Nowadays they are using "smart booms" that do the same thing by measuring pressure distribution at the tip of the boom and working it out with software, but it's still just a way to measure the free stream out where it's minimally affected by the fuselage body.

From that data and from the AOA vane itself, the variations between AOA vane and true are plotted and calibration tables are loaded into the Stall Protection Computer software so the SPC can correct the AOA data internally before it is used for the various functions that need AOA information.


What is the air temperature inside of a tire right after landing?

I'm not sure that there is a maximum design temperature and even if there was it wouldn't be that high, probably no more than 120C.

The problem is not the temperature inside the tyre but actually the temperature internal to the carcass. The hot spots are around the bead area and around the cords on the shoulder of the tyre due to the loading. The rubber compounds will start degrading above 160C. This will be considered in the design of the tyre.

The design will have been tested under representative speeds and loads on a rig and the temperatures checked to make sure that the temperatures are within the required limits. At the Goodyear Technical Centre they have a large steel flywheel which they rotate to represent landing speeds and then use a hydraulic ram to simulate the landing gear and push the tyre onto the flywheel. They cycle this several times and then measure the temperatures throughout the carcass.

An under inflated tyre will suffer increased deflection of the carcass and be prone to over heating. Hence the main concern is then to maintain the correct operating pressure. The tyre will have charts specifying the correct pressure to use for the loading and landing speed.


That fairing covers an antenna for a satellite-based Wi-Fi system.


Why aren't we using drone blimp/hybird airship for delivery?

There are many reasons why that will probably not happen.
Number 1: As of right now drones/blimps are very big for 1 package. It is much more efficient to use a car that can take in hundreds of packages.
Number 2: There are may types of drones/blimps that can be flammable exposed to certain chemicals. Also...where is the drone gong to fly? In airspace where planes are? Where is it gong to land? What about apartment buildings?
Thats why this is not plausible. Maybe one day it will.


If I am understanding your question correctly:
An LVO is Low Visibility Operations which is defined by the FAA in AIM 2-3-4 and 4-3-19 as well as Advisory Circular 120-57a & ICAO OPS Low Visibility Operations (LVO)

Low visibility operations are those that occur when the runway visible range (RVR) is below 1200 feet (360m).

So, your RVR above 600m would not indicate the need for LVO.
A Ceiling is defined by the FAA

Ceiling means the height above the earth’s surface of the lowest layer of clouds or obscuring phenomena that is reported as “broken,” “overcast,” or “obscuration,” and not classified as “thin” or “partial.”

And, Broken (BKN) cloud layer is defined in AIM 7-1-31

9. Sky Condition.
The sky condition as reported in METAR represents a significant change from the way sky condition is currently reported. In METAR, sky condition is reported in the format:
Amount/Height/(Type) or Indefinite Ceiling/Height
(a) Amount. The amount of sky cover is reported in eighths of sky cover, using the contractions:
SKC clear (no clouds)
FEW >0 to 2/8
SCT scattered (3/8s to 4/8s of clouds)
BKN broken (5/8s to 7/8s of clouds)
OVC overcast (8/8s clouds)
CB Cumulonimbus when present
TCU Towering cumulus when present
Note 1: “SKC” will be reported at manual stations. “CLR” will be used at automated stations when no clouds below 12,000 feet are reported.
Note 2: A ceiling layer is not designated in the METAR code. For aviation purposes, the ceiling is the lowest broken or overcast layer, or vertical visibility into an obscuration. Also there is no provision for reporting thin layers in the METAR code. When clouds are thin, that layer must be reported as if it were opaque.

So, the cloud layers you described as FEW001 or SCT001 would not be considered a ceiling. And, they would not be considered IMC.
More insight on what can be done at the MAP can be gathered from this question:
Missed Approach below DA/DH


Could I use a powered parachute to fly around New York City?

Pretty simple, powered parachutes fall under the ultralight vehicle category, which is 14 CFR 103:

14 CFR 103.15 Operations over congested areas.:

  No person may operate an ultralight vehicle over any congested area of a city, town, or settlement, or over any open air assembly of persons.

And Also:

14 CFR 103.17 Operations in certain airspace.

  No person may operate an ultralight vehicle within Class A, Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from the ATC facility having jurisdiction over that airspace.

It is highly unlikely that you would get a waiver to fly your PPC in the Manhattan Class-B, even if 103.15 didn't preclude it in the first place. You can fly in Class-B in certain areas, but you do need to be talking to ATC.


Is it true that a soda can or a bag of chips will pop in a plane at high altitude?

Not likely.  Consider how food products normally make it to you.

Any competent US maker of soda or chips will design their product to be shipped

on Interstate 70 or 80, via Sherman Summit (8650') or the Eisenhower Tunnel (11,158')
or more likely by rail, via again Sherman Summit (8015') or Moffat Tunnel (9239').*
Aircraft are pressurized to a pressure altitude of 8000' typically, so Sherman Summit (rail).

If a food manufacturer were to botch their packaging, they wouldn't have your problem of a soda can bursting, they'd have an entire container load of sodas or chips burst and ruined for sale.  That is simply unacceptable, so manufacturers have a big incentive to get this right.

Other markets will have similar issues - the EU has the Alps, and China and India have the Himalaya. It does not apply to regional sellers in flatland areas, so a regional/indie Florida chipmaker, all bets are off.

It does, however, apply to soda manufacturers, whose cans must endure extreme temperature (e.g. solar loads in a car) also in high places.

* Tennessee Pass (10221') doesn't count, it is weedgrown, rusty and cut in several places, being held for future capacity needs.


How to figure unusable sectors if the VOR is not colocated at/near an airport?

The US Chart Supplement will give you the necessary information you seek. The supplement lists a plethora of information on airports, airfields, heliports, NavAids, Flight Service Stations, ATC facilities, other aviation facilities, preferred routes, TEC routes, etc. You will find the useful and usability information for all of the NavAids listed in the entry for that particular NavAid. Regardless of if the same information is listed in the entry for an associated airport.
The US Cart supplement is generally organized in the following hierarchy:

Geographical region
State
City center
Facility name

I would imagine this is done to put the facilities in the same general geographical vicinity of each other grouped together in the supplement for ease of use when navigating in that area.
You can get the facility name from the either the VFR or the IFR sectional charts. Reviewing the information for the NavAid would be a good idea if you intend to use it for navigation. Similar to reviewing the information for the airfields of intended use.
As to why the unusable sectors of a NavAid are not depicted on the sectional chart? I would imagine it is just a matter of ease of use. The sectional chart is already cluttered with invaluable, important, critical information. Putting more information would get it to the point of overload and unusability as a navigation resource. Keeping it as an overview works well. Hence, the Chart Supplement is necessary to provide targeted information for your particular flight.

The unusable “sectors” of the VOR are not based on track, bearing, course or heading. They are based on the radials of the VOR. If you are on a radial depicted in the NavAid, airfield, or other facilities information, you must consider its usability.
If you are dialing/tuning into a specific radial, or if you are located on a specific radial (extended out to depict capturing the radial with a centered CDI regardless receiving thee signal) it does not matter where on the radial you are located.
Case in point. KLOL lies roughly on the 155 Radial of the LLC VOR. Yet, the airport lies on a 171° True Course from the LLC VOR with a 16° magnetic variation. The Wind Correction Angle will determine your Magnetic Heading. If the magnetic variation changes (which it does), but the VOR is not updated to the change, the radial will stay the same even though the Magnetic Course will be different.


Using a standard PC gaming / smartphone headset for passengers in a small plane

This is an interesting question. But, I don’t see what this solves. There are aviation headsets as cheap as $50. That is as cheap as gaming headsets. But, they are specifically designed for aviation to include passive noise reduction. There would be no advantage to using a gaming headset in aircraft.
The primary purpose of aviation headsets for the pilot is to provide clearer communication between the pilot and ATC. But, that purpose shares equal importance with the goal of hearing protection.
Small, General Aviation aircraft are very loud. But, aircraft have speakers and microphone handsets that make communication with ATC still possible. In decades past, headsets were not even worn in enclosed cabins. And, it has only been recently that the effects of noise has been considered a factor in fatigue. Unless the headset addresses the concern of noise reduction, it is of little benefit in the aircraft.
For passengers, noise reduction can be accomplished with industrial or firearm hearing protection. Non-crew member military personnel function with only standard earplugs aboard aircraft. Communication between personnel in the aircraft even with the doors open is accomplished through shouting over the ambient noise. As far as the pilot turning off a Bluetooth device to enforce “sterile cockpit” practices, that can already be accomplished as a built in function of the aircraft audio panel.
So, although a very simple adapter could be built to enable gaming headsets, cellphone headsets, and earbuds to be used in aircraft, it does not truly solve the problem you posed so far. And, it is not truly better than purpose-built aviation headsets. However, my purpose-built aviation headset is Bluetooth enabled, and can be used with a Bluetooth enabled computer like a gaming headset.


Which official document lists active airport identifiers?

The FAA JO 7350.9L - Location Identifiers contains complete lists under decode subsections organized alphabetically. Example:


Have there been any attempts to standardise pay across different aircraft types?

Jumbos and widebodies are harder to fly than amateur pilots often think. The larger and more complex the aircraft, the further ahead in time the pilot has to be thinking in order to get the plane where he wants it in the configuration he wants it. This increases pilot workload even when "just cruising".

There is a natural progression from smaller to larger planes and fewer to more passengers through all levels of pilot training and certification. You don't put a student pilot in an A380 with 500 passengers aboard for their first solo flight. You give them an LSA costing $25-50k and don't allow them to carry any passenger besides their instructor. As the pilot gains skill and experience, they transition to larger and more powerful aircraft and gain more privileges and responsibilities. Parallels abound; knowing how to drive a 19-foot speedboat on a lake is no qualification to be at the helm of the Carnival Magic, or the U.S.S. Ronald Reagan. Knowing how to drive a go-cart in a parking lot is no qualification to be behind the wheel of a road train.
Case in point, someone who just got their ATPL/AMEL likely has had zero stick time in an actual airliner; they're simply too big and expensive to run for flight schools to be using them for flight training. What they've probably logged actual flight time in for an AMEL category rating is closer to a Gulfstream or Learjet; a high-performance narrow-body T-tail. That's not really going to cut it for a 737, but that experience transfers pretty seamlessly to a regional narrow-body airliner like a Bombardier or Embraer; slightly bigger and heavier but not totally out of the ballpark in configuration and performance envelope. Establish a good track record in those and you work your way to the 100-seaters like the E195, and from there you can continue to work your way up as your experience and mentality allow you to handle the longer lead times and increased complexities of bigger jets.

Smaller flights tend to bring in less revenue and lower margins, primarily due to increased competition on those routes. Yes, the seats turn over more quickly as the smaller jets make shorter hops, but do the math; DFW-PHX costs about \$320 a seat, you have about 130 seats on a 737 or A320 running that route, and you can run it about 3 flights between those two airports gate-to-gate in 10 hours. Total revenue, somewhere in the ballpark of \$125,000 a day. A ticket from DFW to LHR costs about \$2200, it's run with a 777-300ER which carries about 320 people per flight, and you run that once in the same 10 hours. Total revenue for a full flight, about \$700,000. Even given that the DFW-LHR flight will probably require two crews and the fuel costs per passenger mile will be higher, you're still making more money off the larger plane, provided you can fill it.
Now, this very same cost breakdown doesn't seem to hold at first for a smaller regional jet. Waco to DFW is an hour gate-to-gate and costs ~\$325 a ticket. In the same ten-hour flight time of the DFW-LHR flight, a 50-seat ERJ145 could theoretically bank up to \$162,500, more than the DFW-PHX flight. But, nobody's paying \$325 to fly from Waco to DFW unless they're "stupid rich"; you can drive between those cities in an hour and a half for the cost of about 5 gallons of gas, and people know that. They also know that if they're going to DFW to catch another flight for a week or ten-day trip, the parking fees will eat them alive. A more realistic scenario is ACT-PHX via DFW. That ticket costs \$360. Recall that DFW-PHX by itself was \$320, so your passengers are paying more like \$40/seat for the regional connector, and at that rate 10 trips with a 50-place jet would bring in a scant \$20,000/day, which might barely break even on fuel and fees to operate that route.

Older pilots want more pay. As in many industries, workers expect their experience to count for something on their pay stubs. From simple cost-of-living raises to the money needed to raise a family and eventually retire, airline senior captains often end their careers in the low to mid six figures. They also start lower on the pay scale and so get less of a head start building a home and retirement; regional jet operators start around $22,000 which is just above poverty line (which is part of the complaint; a pilot's starting salary is not a living wage especially considering what it takes just to be able to apply for the job). Given the costs of flight training, and the starting salaries of other skilled trades, learning to fly for a living is not the obvious choice. So the ones that stick with it and work their way to senior captain expect to make up the difference at the end of their careers.

Given all of these points, it makes sense to put junior pilots making less money in smaller airliners, and increase the airframe size and the pay as a pilot advances through their career.


When is this Class D airspace not Class D airspace?

Great question. The short answer to your question is "Full Time." Ultimately that Class D airspace will be incorporated into the LAX Class B, but there is a lot of red tape involved so step one was to add the Class D extensions, then it will be incorpoated into LAX Class B at a later date. Its a big deal, Title 14 CFR Part 71 had to be amended, here is the Federal Register page that explains the rule change. By the way, you're not alone in being confused about the effective hours, apparently that language was erroneously included in the charts and had to be removed.


What navigational aid(s) would WWII bomber pilots have used while flying in instrument conditions?

what navigation aid(s) would these pilots have used while flying on
  instruments?

The short answer is the guy sitting behind them (aside from your standard 6 pack)

On planes of this size and of this era most of the navigation and operation of navigation instruments was up to the flight navigator. They sat behind the pilot and sometimes had other instrumentation back there. In many cases they had a table and a decent map as well as some stop watches a pencil and a good straight edge. The pilots were responsible for things like heading hold, altitude hold, and speed hold. Although some planes even had aft placed throttles out of reach of the pilots.

(source)

In areas of the world where NDB's and Other early radio nav ads were not really present pilotage and dead reckoning were often used. Keep in mind VOR's were not deployed until 1946.

Celestial navigation was also used however that is dependent on sky condition at the given time.

This B-29 "FiFi" Navigators station shows a pretty sparse setup of instrumentation that appears to include some kind of ADF style read out.

(Source)

This site provides a great overview of some of the nav equipment used at the time.

You can find the full 1945 "Flight Through Instruments" Naval Aviator publication here.

According to this article the B-18 did fly with a navigator

  The crew, numbering three, constituted the pilot and flight navigator
  in the traditional cockpit position over the nose with the bombardier
  seated in the position at the nose proper.

Early versions were even used to train navigators,

  Work began in earnest on a variant specifically for training military
  pilots, bombardiers and navigators.

  the "loop antenna"

The loop antenna is a part of early ADF systems and on occasion can still be found on some aircraft (see ADF loop below).

(source)

The loop antenna is one of two components needed for an ADF system. It is the component that can detect direction. However it only has 180 degrees of precision and is ambiguous beyond that. In other words it does not know if the signal is from the front or the back. The ADF Sense antenna solves the ambiguity problem (if installed).


What is the proper ICAO phraseology to activate a flight plan?

The UK CAA Radiotelephony Manual (CAP 413, Edition 22, May 2016) has an example of how to activate a flight plan in chapter 3, section 3.36 (page 92 in the PDF).

  Aircraft G-CD, departed Seton at 38 request activate flight plan
  ATC G-CD, departure time 38 will activate flight plan

There is no indication whether this is for VFR or IFR flight plans, so it should apply to both if a filed flight plan wasn't activated at departure.

I also pulled out my (fairly recent) radiotelephony textbook, which covers EASA up to and including PPL including in English (and thus should be pretty close to the official ICAO phraseology), to double-check what it says. (I don't often fly with an actual flight plan active.)

  Aircraft ATC callsign, aircraft callsign
  ATC aircraft callsign, ATC callsign, go ahead*
  Aircraft aircraft callsign, activating VFR flight plan, departed airport, hour hour minute minute, to destination airport
  ATC aircraft callsign, activating VFR flight plan, hour hour minute minute
  Aircraft aircraft callsign

For example, Smallprop 123 flying VFR in airspace controlled by Somewhere Control, with a previously filed but not yet activated flight plan:

  Aircraft Somewhere Control, Smallprop 123
  ATC Smallprop 123, Somewhere Control, go ahead*
  Aircraft Smallprop 123, activating VFR flight plan, departed Hometown, one two tree five, to destination Springfield
  ATC Smallprop 123, activating VFR flight plan, one two tree five
  Aircraft Smallprop 123

*) the "go ahead" may be omitted

The exception to this is if you are departing from a controlled airport, in which case a flight plan filed prior to departure is activated automatically. Activating a flight plan manually is only required when departing from uncontrolled airports.

To close a flight plan, the phraseology after establishing contact with ATC is:

  Aircraft Smallprop 123 position Wintermeadow closing VFR flight plan from Hometown to Springfield
  ATC Smallprop 123, flight plan closed at time one tree tree zero
  Aircraft Flight plan closed at time one tree tree zero, Smallprop 123


What does happen when a supersonic aircraft passes another supersonic aircraft, regarding sonic booms?

When supersonic aircraft flying opposite routes cross each other, do pilots hear a sonic boom?

If the aircraft are near enough, yes.

  If they fly in the same direction, with the appropriate offset, does one hear a permanent sonic boom?

The boom will not be permanent i.e. static, but yes, it will be persistent. However, it should be noted that the shocks from various parts of the aircraft body will interact nonlinearly (mostly coalsce), resulting in unpredictable results.

  If two aircraft fly in opposite directions at Mach 0.6, can they create a sonic boom by adding their individual shockwave speeds?

No, sonic boom is caused by the object travelling faster than sound while the disturbances travel in the medium with speed of sound and get 'bunched up'. So, the aircraft has to fly supersonic with respect to the medium

  What are the effects on the aircraft?

Shock wave is basically a pressure discontinuity. So the effect will be similar to that of an impact, whose strength depends on the shock wave.

  Is there a distance after which the effects become insignificant?

Yes, but it depends on the aircraft size and the speed. The shock wave produced by the bullet loses its strength in a short distance, while the Concorde has to be flown over sea and Tu-144 at over 35000' to mitigate the effects.


Can a student pilot start flight training before they get their student pilot certificate and medical?

Yes.

14 CFR 61.87(n)

  (n) Limitations on student pilots operating an aircraft in solo flight. A student pilot may not operate an aircraft in solo flight unless that student pilot has received:

    (1) An endorsement from an authorized instructor on his or her student pilot certificate for the specific make and model aircraft to be flown; and

    (2) An endorsement in the student's logbook for the specific make and model aircraft to be flown by an authorized instructor, who gave the training within the 90 days preceding the date of the flight.

14 CFR 61.23(a)(3)

  (a) Operations requiring a medical certificate. Except as provided in paragraphs (b) and (c) of this section, a person— ...

    (3) Must hold at least a third-class medical certificate—

      (i) When exercising the privileges of a private pilot certificate;

      (ii) When exercising the privileges of a recreational pilot certificate;

      (iii) When exercising the privileges of a student pilot certificate;

The student pilot only needs a student pilot certificate and medical when operating in solo flight.

With that said, if there is any doubt that a medical certificate won't be granted it is a good idea to get that out of the way before spending money on flight training you will never be able to use.


Do ailerons on opposite wings move together?

On most general aviation airplanes, and other cable-controlled aircraft, they move together and for that matter are cross linked to the same physical cable. You can see this nicely on the control diagram for the B-24

(source)

Some ailerons are designed to counteract adverse yaw and may move such that they are asymmetrical to the flow over the wing.

  1) Differential Ailerons: One aileron is raised a greater distance
  than the other aileron is lowered. The extra upward aileron movement
  produces more drag change than an increase in AOA on the downward
  aileron. This produces an increase in drag on the descending wing,
  which reduces adverse yaw.

  2) Frise Ailerons: The aileron being raised pivots on an offset hinge.
  The leading edge of the aileron is now pushed into the airflow,
  creating drag and reducing adverse yaw. In this case, frise ailerons
  are using form drag to counter induced drag.

But not all aircraft contain such systems. Fly-by-wire systems are theoretically capable of deflecting any control surface as they see fit and may not move symmetrically but generally speaking their direction of movement is opposite. Some fly-by-wire aircraft even have split ailerons which may see parts of a give aileron deflect differently. This answer covers that quite nicely.

If you really want to go back, the 1912 Farman HF.20 had single action ailerons that only deflected downward and were pushed back into position by the airflow. I would say (if these count as ailerons) that they do in fact not move in tandem. There were some other early designs covered here that worked a bit differently than modern ailerons.

As for your second point, aircraft that have elevons, which serve as both the elevator and the aileron (mostly delta wing stuff like the Concorde and other high speed airframes), can move the surfaces in the same direction. Generally other surfaces are employed for the use case of needing to move both ailerons in the same direction (speed brakes).


If you're under the hood in VMC + VFR, you could have an appropriately rated pilot (i.e. PPL) in the other seat as the safety pilot. If the other pilot is instrument rated (but not a CFII) + is the PIC for the flight, you could even be the sole manipulator of the controls in IMC + IFR, although that gets into the questions about logging PIC vs acting as PIC, which is its own set of issues. The "safety pilot" option is probably more typical.


Runway landing with a front skid instead of wheel - how does steering happen? (Dreamchaser)

Like many aircraft that dont have a steerable nose wheel they most likely use differential braking. Here is a pretty interesting paper that covers some of the testing they did on the airframe. Steering is not really a large concern for the Dream Chaser (or the space shuttle for that matter) as it has no power to maneuver on the ground anyway. Generally speaking it will be towed off the runway.

According to this source SNC notes similar reasoning to the X-15, simplicity as well as concerns around tires in a space environment (which is interesting seeing as the space shuttle had them).

  Speaking of the rationale for opting to use a skid strip, SNC noted it
  is a simple, light, safe option. They also added that there had been
  some issues with the analysis of the performance of tires in the space
  environment and this eliminates one of the tires – with the other two
  tires easier to control than the nose wheel if there’s a problem with
  one of them.

  SNC noted they do not expect any crosswind limitations from the skid.

Although here is a fairly interesting NASA press release on testing the "nose gear" for the Dream Chase implying there may have at one point been gear there.


Would biplanes be of use in VSTOL applications? What is the down side to biplanes? ex. Bush Pilots or VSTOL competitions

You're quite right in not doubting the capabilities of biplanes, like Curtiss Pitts with the fully aerobatic Pitts Special.

Aerodynamically, the classic biplane has many disadvantages, with drag being built in everywhere. Like designing an aircraft with a built-in airbrake that is deployed all the time. The double wing creates more drag than a single wing, the struts create extra drag, and the cross-wires between the wings are easy to miss on photo's but are huge contributors to drag as well.

Structurally though, a biplane design is quite advantageous. The biplane configuration acts like a box design, much easier to integrate with the fuselage than the cantilever clean wing with its bending moment at the wing root. So if the construction is exposed to high acceleration like a fully aerobatic plane, there is less aeronautical engineering involved. As usual in aeronautics, aerodynamic disadvantages equate to structural advantages.

But zooming out even further, it makes little sense to create lift together with a lot of drag. Aerodynamics determines the stall speed of an aircraft, the biplane has no advantages here. If the objective of the bush pilot is to fly slowly and inspect, and to have VSTOL capabilities, there is a much better option available: the autogyro. The owner of Quobba Station in Western Australia has built one himself and uses it for inspecting his huge property. They are used as airborne motorcycles for sheep mustering etc. Upon engine failure (which has happened), it can be landed safely anywhere on the property. Just bring a hat.

Update

The thought that biplanes must have slower stall speeds than comparable monoplanes keeps nagging me, but I cannot find an explanation or indication that that is actually the case. For instance for the Tiger Moth: Stall Speed = 40 KIAS @ 827 kg. For the Cessna 172: Stall Speed = 40 KIAS @ 1145 kg.

A biplane could be designed for lower stall speeds and good climb performance: make the wing area much larger than required, with an associated lower wing loading. But this can be done in a monoplane as well:

Simply use a large single wing.
Increase wing area in landing/low speed configuration by using Fowler flaps.
Increase wing camber in landing configuration.

And then it becomes a matter of economics, is it cheaper to build a biplane than it is to build a monoplane with fancy flapping arrangements? Probably. But all the dragginess will cause much higher fuel consumption, and it will take a long time before the pilots get to where they want to be.


What to do with excess fuel before flight?

You have a few options,

You can burn it off. Laps in the pattern are great for this. Get to the airport before you need to depart and practice some landings. This may cost you in terms of dollars but at least you are not just dumping it.

You can dump it into gas cans if you have them. Every small GA plane i have ever encountered (mostly pipers) has fuel sumps for testing your fuel during your preflight. Most of these sumps can be latched open and you can drain it into a gas can for use later. you should always test for water before doing this. If you rent you should ask the FBO what their policies are on dumping/reusing fuel. I cant find any specific legislation on it but it seems that its common practice (for the airlines at least) to only put the fuel back in the same plane (or within the same fleet) to prevent cross contamination of things that can build up in the tanks.

The sump on the pipers I fly looks like this

(source)

Dont have the plane filled up. If you rent planes like many GA pilots do and you plan to take up 4 friends for an evening sight seeing flight ask the FBO to not fill the tanks if someone is using it before you.

Dont use all the tanks. This will vary plane to plane but some planes have 2 or more fuel tanks which may be independently selectable. You may be able to (weight and balance permitting) keep some of the tanks dry if you know you regularly short hops with big loads.

For the sake of a complete answer I will mention that planes can be flown over gross weight, I don't advocate this nor would I ever attempt it but it does happen here and there, here is a discussion on it if you are curious.


What is the drag (or $C_D$ vs $C_L$) of the Airbus A320 in cruise flight?

I need to make a few assumptions to close the gaps in the data you provide.

The aircraft flies close to its optimum L/D - which is 18 for the A320-200 in cruise. So the $c_D$/$c_L$ is 0.055556.
The aircraft is close to its maximum take-off mass, minus fuel for climb. Let's pick 76 tons.

Now the drag force is 1/18 of the weight force. Weight is mass times gravitational acceleration: 745,300 N. So drag would be 41,406 N at this point.
At the end of the trip the aircraft has burnt through 15 tons of fuel; now the drag is a mere 34,300 N. Note also that it now is flying quite a bit higher than initially in the flight, so both friction and induced drag have become smaller.


How useful are the AOA Indexers and indicators for jet pilots and civillians?

They’re super useful once you get used to them. No matter your weight, if you fly at the right AOA you’ll have the right stall margin. It is easier to see the indexer than the ASI, for control on approach. It acts like a pitch rate indicator too, if you are rough with the nose, so it helps to smooth out the flying. Responds much faster than the ASI. If you are maneuvering aggressively, it will give you that stall margin too.

Update with nice paper from AIAA Journal of Aircraft:

"Low-Cost Accurate Angle-of-Attack System", Borja Martos and David F. Rogers, Journal of Aircraft 2018 55:2, 660-665

  ...The angle
  of attack for maximum lift-to-drag ratio corresponds to maximum range
  and maximum glide ratio for a piston engine- propeller aircraft.
  Hence, in a fuel critical situation and/or an engine failure
  situation, it is critical that the pilot have accurate access to this
  angle of attack.

  With today’s fuel costs, the Carson cruise [1] angle of attack, which
  represents the most efficient way to fly fast with the least increase
  in fuel consumption, is of significant interest.

  The angle of attack for maximum lift-to-drag ratio does not depend on
  density altitude, weight, or load factor but only on aircraft design
  parameters and aircraft configuration. Similarly, the angles of attack
  for minimum power required and Carson cruise depend only on aircraft
  design parameters and configuration...

  Therefore, a low-cost, accurate, full envelope, easy to flight
  calibrate angle-of-attack system is a transformative technology for
  light general aviation aircraft.


How can the range of an aircraft be calculated given real wind conditions?

The best answer: Use the charts in the respective Pilot's Operating Handbook (POH). There you should find correction factors for the parameters which influence aircraft range

Fuel on board: The more, the better. But note that doubling fuel will not double range.
Take-off mass: If you take no payload, the aircraft will produce less induced drag and reach a slightly higher range. See the chart below for an example.
Wind enroute. Follow the link; the wind component parallel to your flight direction will change the range by the product of wind speed times flight time.
Cruise altitude: This depends on the type of engines, jets benefit more from altitude than propeller aircraft.
Temperature

Generally, there should be a chart like this:

It plots the maximum achievable range over the aircraft's payload and assumes that the tanks are filled such that the flight starts with the maximum take-off mass. The chart should also have an explanation that clarifies which altitude and which thrust setting were used.

Or you use approximations like Breguet's range equation, which require detailed knowledge of the aircrafts L/D and the engine's fuel consumption. That will be the weakest point of any range calculation: Sufficient data how changes in the aforementioned parameters affect the result.


How to decide on a rate of climb or descent if no specific vertical speed is required?

In general terms, the higher you are the better your fuel efficiency, so you will want to climb quickly and then stay as high as you can until you need to start your descent in order to land.  For jets, a common way to approximate your top of descent is by using the "3:1 rule" where you take your desired altitude loss in thousands of feet and multiply it by three.  For instance if you need to lose 35,000 ft. you would start down 105NM ($\frac{35000ft \times 3NM}{1000ft}$) prior to your destination, staying at altitude until then in order to save fuel.

As far as your rate, the first place I would check would be the AFM of the airplane that you are flying.  Smaller airplanes will have Vy (best rate of climb speed) that may be used for this purpose unless another speed is specified (to help with cooling, etc).  Larger aircraft often have specific climb and descent schedules (for example, climb at 250 KIAS until 10,000 ft then 300 KIAS until you transition to Mach 0.76) which the manufacturer recommends and provides performance information for.  Fly these speeds and take what vertical speed that you get.  Usually, flying by the book is the place to start unless you have a specific reason to do otherwise.

The AIM 4-4-10 says:

  d. When ATC has not used the term “AT PILOT'S DISCRETION” nor imposed any climb or descent restrictions, pilots should initiate climb or descent promptly on acknowledgement of the clearance. Descend or climb at an optimum rate consistent with the operating characteristics of the aircraft to 1,000 feet above or below the assigned altitude, and then attempt to descend or climb at a rate of between 500 and 1,500 fpm until the assigned altitude is reached. If at anytime the pilot is unable to climb or descend at a rate of at least 500 feet a minute, advise ATC. If it is necessary to level off at an intermediate altitude during climb or descent, advise ATC, except when leveling off at 10,000 feet MSL on descent, or 2,500 feet above airport elevation (prior to entering a Class C or Class D surface area), when required for speed reduction.

  NOTE- Leveling off at 10,000 feet MSL on descent or 2,500 feet above airport elevation (prior to entering a Class C or Class D surface area) to comply with 14 CFR Section 91.117 airspeed restrictions is commonplace. Controllers anticipate this action and plan accordingly. Leveling off at any other time on climb or descent may seriously affect air traffic handling by ATC. Consequently, it is imperative that pilots make every effort to fulfill the above expected actions to aid ATC in safely handling and expediting traffic.


Why Boeing 737 main landing gear wells have no doors?

To keep costs down. The extra friction from no gear doors is more than made up from the weight savings.


Please explain real-world procedures behind this "ATC joke"

As you commented, it's a play on "state [say] your intentions". However, the pilot has said his intentions several times and ATC rejected them each time, so he's turning it around by asking ATC to tell him what intentions won't be rejected.

The "intentions" in this case are the type of Instrument Approach Procedure (IAP) he wants to use. Typically there are several for each runway, for use by aircraft with different levels of equipment; ILS, VOR and ADF (actually NDB) are common options in order of decreasing desirability.

Depending on the weather, there may be two additional IAPs available at any airport which aren't usually charted: visual and contact. There's a possible second-level joke here in that ATC isn't allowed to offer a contact approach, but the pilot is allowed to request it--so if the pilot is asking ATC to tell him his intentions, then in the logic of the joke, ATC could tell him he's requesting that. OTOH, if the weather were such that a visual approach were available, ATC probably would have assigned it to him already without any requests.


Is it practical to install seat belts in airline lavatories?

While it may appear at first glance that a seatbelt could simply be installed, it is not a simple answer. There would actually have to be some significant certification analyses and testing done. Seat belts tend to be fabric. While those fabric lap belts are approved for the rest of the cabin, the lavatories have different certification requirements especially regarding propagation of a fire in the enclosed space. There would have to be fire certification testing done and analyses to verify that the information gained during the certification testing was applicable to all configurations.

Also, who would want to use or even touch a lap belt that was installed in the lavatory while someone with explosive diarrhea experiences turbulence? Eww! I wouldn't want to use it as a passenger or service it as a mechanic. That is a biohazard.


What is the correct equation for rotor solidity?

Rotor solidity is the area of the rotor disk that is actually occupied by blade area.

Area of rotor blades = $N \cdot c \cdot R$

Area of rotor disk = $\pi \cdot R^2$

$$Rotor \ solidity = \frac{N \cdot c}{\pi \cdot R} \tag{4}$$

So all three of the equations OP found would not be usual. Good reference books are:

Helicopter Performance, Stability and Control by Raymond R. Prouty
Principles Of Helicopter Aerodynamics by J. Gordon Leishman.

Both these books use equation (4) for rotor solidity. It is possible for a factor 2 to pop up in the coefficients which are usually considered regarding disk area and solidity: $C_T, C_P$ and $C_Q$. From Leishman:


Which engine is more efficient between turboprop vs jet?

The short answer to both your questions are Yes. The long answer is, it's not so simple.

The ATR 72 you have pictured has a top speed of 276 knots and a range of 1,300 miles. It can carry around 70 passengers.

This document provides detailed comparisons of burn rates. So we can see the ATR 72 burns about 810 Liters per hour (about 214 gallons/hr). A Boeing 737-400 seats about 150, has a maximum range of about 2,400 miles, and a cruising speed of about 473 knots (almost double the range, and over 1.5 times the speed). But its burn rate is about 3,000 liters per hour (793 gallons).

So is it a strict trade-off? Speed for Efficiency? Well, not entirely.

TAS is true airspeed. That is, the speed of the aircraft relative to the airmass in which it is flying. However, an decrease in density (e.g. high altitudes; air is less dense) will yield an increase in TAS. Thus, it is easier to fly at the same true airspeed at higher altitudes. Since jets are generally used on longer flights (where much of the time in the air is spent at high cruise altitude), they have to work less to fly the same speed as they would 10,000 feet below. There are other reasons why jets are more efficient at high altitudes - they have to combine less fuel with the thinner air, and there is less drag at high altitudes.

So why don't propeller planes fly at high altitudes then? Well, part of it is that turboprops are less efficient at higher speeds and higher altitudes, and jets (turbofans) are more efficient at both (obviously to a point, but airliners don't fly fast or high enough to decrease their efficiency again).

Since jet engines can also produce more thrust, they are better suited to large airplanes, which are the ones used for long distances (e.g. if you wanted a propeller plane the size of an Airbus A380, you would need a lot more than 4 engines). So jets are used in situations where they are more economical, and props where they are more economical.

In summary:

Turboprop characteristics

Efficient at low speed, low altitude
Low thrust

This leads to smaller aircraft on shorter, slower routes, like you've observed, since they don't have to climb or fly fast to get there in a reasonable amount of time. Also these short hops generally require fewer passengers, or flying a second flight is better than needing a much bigger plane.

Turbofan characteristics

Efficient at high speed, high altitude
High thrust

This leads to larger aircraft on longer, faster routes, like you've observed, since they need to fly higher and faster to get there in a reasonable amount of time. Also since these routes are more "popular", and it costs so much to fly that far, it makes more sense to put more passengers on one plane, than two.

In general, an airline would not sacrifice fuel for faster flights if that was the only advantage, unless they knew there could be a price premium for the faster flight (e.g. Concorde).


Are there any reported cases of noise from helicopters causing damage to property?

The article states that it's not even clear the damage was caused by the helicopters, that there is no other known incidence of such damage being caused by helicopters, and that a scientific study has shown that while in theory there could be damage such has not actually been shown to be caused.

In other words, it looks suspiciously like a group of people who want the helicopters gone from a nearby airbase lawyering up with some spurious and dubious claim for which there is no evidence whatsoever, hoping to win public opinion and probably environmentalists rather than having an actual legal case at all.

This is not unheard of in the Netherlands (and elsewhere).

So in short: the article in BN de Stem answers your question already: there is no known instance of such damage happening, and even in this case it's mere speculation that it's happened at all.


Why EU/US airline checked baggage allowance limited at 32kg?

To add to Antzi's answer it is most likely about worker safety. Your question is where do the 50lbs/23kg and 70lbs/32kg numbers come from. The current answer for US based airports would be the recommendations of the Occupational Safety and Health Administration (OSHA). Here is a link to their current lifting standards. There is a neat worksheet down at the bottom for calculating the weight a worker should lift based on the types of movements they have to perform, distances traveled, angles bent. It is a system based on multipliers whose base limit on a normal lift is 51lbs/23.4kg. Then 70lbs/32kg would amount to the multipliers all working out to 1.4 which is again a nice round number.

I would also speculate that at some points these numbers made it into union contracts for ground workers but I have no actual information on that.

What I couldn't find were the OSHA regulations that were in force when IATA first enshrined 23 and 32kg into their rules. It is perhaps a bit disappointing that the current OSHA regulations to not have a "max lift" number but their interest is in reducing injury and a single very heavy lift is apparently less damaging than repetitive above average lifts.


There are a few which are similar on some points, although all have at least one issue. In the end I suspect in the end it's just a "generic mid-wing, twin engined WWII fast bomber"

Other than the radial engines, it looks a lot like a de Havilland Mosquito

Or perhaps a Junkers Ju88

Or a CAC Woomera, at a stretch


What energy density is required for the batteries in order to make an all-electric analogue of the Cessna 150 or similar plane?

Short Answer

Batteries would need to be somewhere around 16.7MJ/kg to give the same range and performance as liquid fuels, this is about 18.5 times the capacity of the best lithium-ion batteries. Price-wise it will cost about 30-35% to charge your airplane as opposed to fill it with liquid fuels at today's prices.

Long Answer

This is a good question which is hard to give an exact answer to, so this will be more of a Fermi Approximation. To answer this you need to look at the energy contained in the fuel and the efficiency of the engine used.

Looking at the energy of the fuel I will use Specific Energy, which is the energy stored in a material per unit of mass. Specific Energy is related to Energy Density, which is the amount of energy contained per unit of volume. Often the terms are interchanged.

The specific energy of avgas and jet fuel is about 43 MJ/kg. The best lithium-ion batteries top out at about 0.9 MJ/kg (the batteries in a Tesla are about 0.7 MJ/kg), so they have a fraction of the storage of liquid fuels. The best battery technology in theoretical development (Lithium-air) has a theoretical maximum of 41 MJ/kg, more realistically they'll get 1/4 to 1/3 of that from the technology, which is still vast.

Internal combustion engines are about 35% efficient, the other 65% is wasted whereas electric engines are much closer to 90% efficient or more.

There are other factors to consider:

Weight: fuel tanks, piping and pumps take weight, and electric motors are much lighter than internal combustion engines. The batteries would need a storage structure but an electric system would probably be lighter overall
Battery inconsistencies: avgas supplies a consistent amount of energy in every single drop whereas batteries will sag as they discharge (this is regulated to give consistent power to the motor, however at some point levels will drop below what is regulatable, so not all the power in the batteries will be usable). Also, over time they lose capacity and become less efficient. Both these factors mean that you'd want to build in extra battery capacity to compensate

So I'm going to assume these two will compensate for each other, the weight savings from going electric will be offset by the need for extra capacity to ensure consistency. Assuming that all other factors are equal (propeller efficiency, etc) we can extrapolate the actual efficiency of the systems to get an approximate figure of an internal combustion on avgas: 35% of 43 MJ/kg = 15 MJ/kg of actual benefit. We can use that figure to determine what specific energy we would need from batteries to get the same amount by dividing by electric motor efficiency: 15 MJ/kg / 0.9 we get 16.7 MJ/kg.

So batteries would need to store 16.7 MJ/kg to give us the same energy as liquid fuels, but how does it compare to existing battery tech? Right now commercially available battery technology is about 0.9 MJ/kg, so it would need 18.56 times more storage capacity (16.7 / 0.9 = 18.56) to supply the same amount of energy.

As for energy costs this is going to vary a lot depending on fuel and electricity prices over time and place; we can use some of the same figures above to work the numbers. I'll assume an airplane that holds 40 US Gallons (150 liters) as the math is easy and it's about the capacity of a Cessna 172. I'm going to do separate calculations for the US and UK to see how they compare:

In the US: Avgas is about \$5.20 per US gallon at the moment, that's \$208 to fill up your airplane of 40 gals. Avgas has about 34.2 MJ/liter of energy, multiply that by 150 liters for 5130 MJ of energy. Internal combustion engines are 35% efficient and electric engines 90%, so we can calculate that an electric airplane would need 5130 * 0.35 / 0.9 =  1995 MJ of electrical power to fill up. 1995 MJ is about 554 kWh, at somewhere around \$0.135 per kWh it would cost you \$75 to charge an airplane with the same amount of energy.
In the UK: Avgas in the UK is about \$2.23 per liter (\$8.47 per US Gallon (ouch!)), so it would cost \$334.50 to fill up an airplane. 554 kWh of electricity costs about \$0.17 per kWh, so it would cost \$94 to charge the airplane

EDIT:
I did consider the efficiency gain from weight loss as fuel is burned, i.e. a variable mass system, I left it out of the answer as it isn't significant compared to the other factors in what is already an approximation. It has to do with the fuel fraction, which is the percentage of the aircraft weight that is fuel, which on a light piston single is comparatively low. A Cessna 172 carries about 40 gallons of fuel, 38 of which is usable, weighing about 228 pounds as opposed to a typical take-off weight of 2200-2300 lbs. In other words its fuel fraction is about 10%, even on a long range flight using every bit of fuel you will only lose 10% of your weight, and I would approximate that you'd get around 5% benefit from it. This was not enough of a factor compared to the other considerations, and it would probably be offset by regenerative descents where the electric motor actually generates power from the spinning prop.

For airplanes where a more significant portion of the weight is fuel, i.e. a higher fuel fraction, efficiency gains from variable mass is a much more significant factor, for example an A380's fuel fraction is 44%.


How do VTOL aircraft like the V-22 Osprey not tilt?

If you think about it, your question applies in exactly the same way to a conventional helicopter. You might expect that it would pitch nose-down if the weight is forward, and nose-up if the weight is aft. In fact, it's even worse for a conventional helicopter, because with only one rotor it would roll (tilt left-right) as well as pitch.

The answer is the same for the Osprey as for a conventional helicopter: the pitch is controlled by cyclic control of the rotor. As the rotor spins, a mechanism inside it changes the angle of attack of the blade (the pitch of the blade) as it rotates. This change can cause it to generate more lift when it's at the rear than at the front (or vice-versa, or left-to-right). This creates a turning moment about the centre of the rotor disk, which counteracts the moment of the unbalanced weight.

You only get so much of a moment with it, though. The aircraft needs that moment in order to change its pitch to manoeuvre. If you had to use the full range of blade pitch (the maximum cyclic control) just to counteract the unbalanced weight, you wouldn't be able to pitch the aircraft any further in that direction. For this reason, the maximum moment of rotorcraft (how far the centre of mass can be away from the centre of lift) is typically smaller than for airplanes.


The image below labels each of the antennas. To summarize based on your groupings:

A: Multi-Role Electronically Scanned Array (MESA) made by Northrup Grumman. It has a similar role to the large rotating dome on the E-3 in tracking airborne targets. Instead of being rotated mechanically, it can be electronically scanned.

B: Communications/Navigation, GPS, ELT (emergency locator transmitter)

C: Missile warning, infrared countermeasure

D: Electronic surveillance

E: Communications

F: Communications

G: Communications/Navigation

H: Missile warning, electronic surveillance

Source


Yes it's for lost comm.  If you look at the MOCA you still have the required obstacle clearance.  MOCA only gives you reception within 22 NM of the NAVAID, while MEA gives reception along the route.  If this was not an RNAV procedure I'd expect your level off altitude would probably be the MEA (just my assumption!).

In this case you would maintain 3,000' until cleared higher.  If you were to lose comm you'd fly the higher of filed, assigned, MEA, or expected altitudes.


What prevents a passenger from hijacking a private jet?

The same thing that prevents the passengers in your car from hijacking it and using it to run people down or drive it through a mall:  It's your private car and you generally know the people that you let in to it.

The same applies to private aircraft.


How much fuel aircraft should carry to complete flight plan?

This may vary elsewhere in the world but according to the FAA FAR Sec. 121.639

Fuel supply: All domestic operations.
No person may dispatch or take off an airplane unless it has enough
fuel--

(a) To fly to the airport to which it is dispatched;
(b) Thereafter, to fly to and land at the most distant alternate airport
(where required) for the airport to which dispatched; and
(c) Thereafter, to fly for 45 minutes at normal cruising fuel consumption
or, for certificate holders who are authorized to conduct day VFR
operations in their operations specifications and who are operating
nontransport category airplanes type certificated after December 31,
1964, to fly for 30 minutes at normal cruising fuel consumption for
day VFR operations.


Why does condensation form on the wing especially during take-off and landing?

Yes, speed and flaps do make a difference.

The lift created by the wings is approximately constant over the duration of a flight. With full tanks, it is higher at the beginning of the flight, and when the aircraft banks, it is again higher to create the centripetal force for changing its course. But the difference is small¹.

Lift is caused by a pressure difference between the two sides of the wing. In cruise, this difference is low but extends over much of the wing's chord. At low speed, however, the suction on the top surface has a peak right aft of the leading edge, so the maximum suction is bigger than it is in cruise. Exactly this changed pressure distribution causes the humidity to condense, because it lets the air's relative humidity rise above the condensation point. In cruise, the pressure change is lower and the dew point is not exceeded. Also, since the airplane flies slower when close to the ground, the air has more time for the condensation to develop.

See below for a color-coded plot of the speed distribution over a typical airliner airfoil in the landing configuration. Red symbolizes the lowest speed (highest pressure), while purple stands for the highest speeds with the lowest pressure. Such suction peaks must be avoided in cruise to enable the aircraft to fly at a high cruise Mach number.

Airliner airfoil with high lift devices in landing configuration (picture source)

¹ The fuel fraction of airliners rarely exceeds 40%, and the added lift in a 30° bank is only 15%.


How do airlines handle communication/notification after an accident?

If an airline has an accident, the chances are you (as the next set of passengers to board that plane) will be the least of their concerns - if there's an incident then it tends to be a case of all hands to action stations to deal with the media, emergency services, families of any potential victims, provide assistance where possible etc. That said, they do have some procedures they attempt to follow. These vary a little from airline to airline.

Most will make an attempt to contact you via text/email if they have it or via the GDS to your travel agent, depending on how far away you are from your departure day/time. It also depends whether you gave contact information to the carrier or your travel agent, whether your travel agent passed it on or, indeed, whether you used a travel agent at all.

The next set of passengers rightly tends to be second priority after dealing with the incident, however. Often if you're on the next flight, therefore, the communication will be a little slow and the first you'll know about it will be when you arrive at the airport - also remember that there's a good chance you're already at the airport, or are on a connecting flight.

If you get to the airport, you'll likely be informed by the staff there who will attempt to get you onto another flight with the same company or another carrier.

As an addition from the comment below, if you're a family member etc who's signed up to flight alerts from the airline in order to hear about delays/diversions etc (some airlines provide this as a service to avoid inconvenience and avoid too much waiting traffic at the terminal), then you'll likely be one of the first priorities. The system is normally set up to send automated or manually-triggered pre-written messages, but in an emergency will usually be used to send a manual message to relevant family members etc.

Obviously this only applies if you've signed up to the service, and only usually applies to the airline's own service: if you've signed up with a third party flight tracking service, they likely have no more information than you do.


How did the 747SR fly from Qatar to London?

I was senior cabin crew at Qatar in 1995/96. Flew on the 747 for about 1 year. My first flight was DOH-BKK-MNL Xmas week 1995. 3 pilots, 14 cabin crew and 1 aircraft mechanic, which was the standard crew numbers. We had 57 passengers all the way to MNL as BKK was in a refuelling stop. If I recall there were 20 First Class seats upper deck and 508?+ seat all economy main deck. The configuration never changed from the ex-ANA seating plans. Gatwick was flown both ways via Cairo and was never full each sector. In the period I worked on the 744, Qatar was still a closed country. There were no tourists and our passengers were mainly workers to and from Doha. After BKK started as a drop off port we would have 1-5 transit pax via DOH. Our Bangkok route which was actually to Manila was a refuel stop only at Dhaka. Flight loads were minimal. First we would only ever have 5-10 max pax. Economy I recall ever having over 200 passengers. The 747sr was also used regularly to Khartoum. They were used also around the Gulf on various flights. The 747sp ex Air Mauritius replaced the 747sr for a few months in the DOH to MNL via BKK with Dhaka dropped. I flew the 747sr on a DOH-DXB-DHA-CMB-DOH route, 20+ hour duty.


Where are the grounded 737 Max planes being kept?

They're at whatever airport they were at (or next landed at) when they were grounded. Airports are big enough places that there's room plenty of room to park planes that aren't currently in use, and it's completely normal to have such planes parked at an airport. Just look at a few in Google Maps satellite view.

At least in Europe (and presumably elsewhere), the directive banning flights does allow one ferry flight (of up to three legs) to get the plane to a location where any corrective action can be taken. But note that this does not allow moving the plane just to get it to a more convenient storage location.

Great Circle Mapper's featured map for 14th March showed the actual location of the 737 MAXes owned by US airlines, as of the previous evening.  Those aircraft are spread across around 30 airports in the US and Caribbean.

Thanks to Antzi for pointing out the ferry flight exception.


You cannot repair a seat belt. You can only replace it.

An owner-operator can perform preventative maintenance on their aircraft. That includes replacement of the seats and/or seat belts.


Did Lockheed test the TriStar in conditions similar to a century of operation?

If a plane of the L-1011's range makes two flights per day for a century without any maintenance breaks, that would be 73,000 flights.
The answer is yes, more or less, literally, if you look at wing loads, or pressurization, respectively. If you account for AOG (aircraft on ground) time, then most certainly yes for both:

A total of 1,696,000 load cycles, simulating 84,000 flights, were applied to the fatigue test airframe. The first 52,000 flights included all loadings, including pressurization. The last 31,500 flights omitted fuselage pressurization, while wing loads were increased from 10 percent to 20 percent over the basic spectrum. This amounted to an equivalent of 115,000 flights. A specific number of load cycles applied by hydraulic jacks to the fatigue test airframe equates to the loads seen in one flight of the aircraft. [emphasis mine]

Since MSN 1000 (second airframe) reached the equivalent of 115,000 flights, it means it did not fail before that, but that doesn't mean that lessons weren't learned and applied to the production airframe, which is one of the purposes of such tests.

Upton, Jim. Lockheed L-1011 Tristar. Specialty Press Publishers and Wholesalers, 2001.


What are these teardrop shaped thingamabobs on the bottom of the Panavia Tornado?

They appear to be related to changing the oil.

The Tornado's flight manual is available online. Page 448 shows what seem to be the features you're talking about:

The features are the ones marked as "12." The previous page has a legend describing them simply as "engine oil."

This probably also explains why they're not placed symmetrically. It seems the engine oil access is off to the side, so each teardrop is a bit to the right of the engine's center line (that's most visible in the second picture).


As a Brazilian pilot, can I buy an aircraft in the US then fly it to Brazil to register it?

I'm not sure if you're asking about general export regulations, in which case Farhan's link is useful, or the more specific licensing question.

But regarding licensing it's clear that you may not fly a US aircraft from the US to Brazil with only a Brazilian license. 14 CFR 61.3 says:

  (a) Required pilot certificate for operating a civil aircraft of the
  United States. No person may serve as a required pilot flight
  crewmember of a civil aircraft of the United States, unless that
  person:

  (1) Has in the person's physical possession or readily accessible in
  the aircraft when exercising the privileges of that pilot certificate
  or authorization—

  (i) A pilot certificate issued under this part and in accordance with
  §61.19;

  (ii) A special purpose pilot authorization issued under §61.77;

  (iii) A temporary certificate issued under §61.17;

  (iv) A document conveying temporary authority to exercise certificate
  privileges issued by the Airmen Certification Branch under §61.29(e);
  or

  (v) When operating an aircraft within a foreign country, a pilot
  license issued by that country may be used.

In other words, you can use your Brazilian license to fly a US aircraft in Brazil (see 61.3(a)(1)(v) above) but otherwise you need a US license or a special authorization (61.77 covers leasing and commercial operations so it almost certainly won't apply to you).

I know very little about this, but at least in theory it looks like your options are:

Get a US license yourself, perhaps a foreign-based license based on your Brazilian one (see 61.75)
Get some special permission from the FAA
Pay a ferry company to fly or transport the aircraft to Brazil
Register the aircraft as Brazilian before it leaves the US (this may not even be possible)

And those are only the FAA/aviation issues, you have to think about customs and general import/export regulations too, both in the US and Brazil. I would look for some specialized help with this.


What are the key differences between controlled and uncontrolled airspace under the FAA jurisdiction?

This Document covers all the regs pretty well. But in short the key point on class G (uncontrolled) is

  Although ATC has no authority
  or responsibility to control air traffic, pilots should remember
  there are visual flight rules (VFR) minimums which apply
  to Class G airspace.

Class G airspace also holds no specific entry requirements (aside from VFR minimums), no specific aircraft equipment (no radio, no transponder etc) and no minimum pilot certificate requirement (but you still need a license (one of a few varieties) you just don't need anything in addition like the instrument rating requirements for class A). On the contrary glass G airspace (uncontrolled) is not a free for all and you are not free to do as you please in some regards. While ATC has no reach into Class G the FAA does and you are still bound by the regulations the FAA puts forth that apply to class G airspace.

Likewise the definition they provide for controlled is

  Controlled airspace is a generic term that covers the
  different classifications of airspace and defined dimensions
  within which air traffic control (ATC) service is provided
  in accordance with the airspace classification.

If you are wondering what the specific purpose of ATC is they define that as well,

  The primary purpose of the ATC system is to prevent a
  collision between aircraft operating in the system and to
  organize and expedite the flow of traffic.


How can pilots obtain runway length information for airports that do not appear in the chart supplement?

If an airport does not appear in the Chart Supplement, the only official information about it seems to be in the relevant Sectional Chart.

In the case of Horseshoe Acres (FA24), the sectional shows that the longest (and only) hard-surface runway is "18", which means 1770 to 1869 feet.

In the case of Brady Ranch (80FD), the sectional shows that the longest (and only) hard-surface runway is "46", which means 4570 to 4669 feet.

Note that you can only guess the runway numbers, the lengths of shorter runways, and the presence of unpaved runways. As @RonBeyer comments, since you have to get permission to land on these fields anyway, it's probably best to ask for such details at the same time. If you get data from the airport operators themselves, that would seem to qualify as official.

However, Airnav and others have lots of consistent data about many airports not in the Chart Supplement, particularly private ones, so it's possible there is some other common source. Since I don't know what that might be, I can't guess how official it is.


The rolling takeoff is a STOVL or Short Takeoff and Vertical Landing operation.  The F-35B is too heavy to hover with full fuel and a warload, but can use its vertical lift system to augment lift generated by the wings allowing an F-35B to lift off in less than 500ft ground roll with a Vr of around 70 knots or so.  The procedure is also used by Harriers flying off assault ships as well.  Some carriers likes the Royal Navy’s HMS Queen Elizabeth make use of a ‘ski jump’ to augment the takeoff roll and launch the aircraft upwards, allowing for a greater launch load and/or shorter takeoff roll.

Once the warload and at least 60% of the total fuel capacity has been depleted, the F-35B can enter into a full hover and land vertically.  This allows the F-35B to recover on an assault ship without the use of arresting gear.

An additional variant of the F-35, the F-35C, has a larger wing and tailplane, different landing gear and an arrestor hook in the tail.  This allows it to launch and recover aboard larger CATOBAR aircraft carriers, but cannot do so aboard assault ships like the F-35B can.

The pointing signal by the launch officer is the takeoff signal.  It can be used as instructions to fire the catapult/EMALS or for the pilot to release brakes and make a short takeoff, as in this case.


Why were the TWA TriStar middle seats smaller than the aisle seats?

Those seats aren't smaller! TWA had fold over seatbacks, resulting in a nice table for the seat next to you if the flights weren't full. They are the exact same size as the other seats. Also, those things down the centerlines between the seats were coat closets.

Later replaced by a full width seat when they went from 2-4-2 to 2-5-2 in their last configurations.


What does the isolation valve do in the landing gear extension/retraction system?

As a general answer: the purpose of an isolation valve is to separate two (or more) parts of a hydraulic system from each other. The separation is necessary to prevent a failure of one part of the system affecting the rest of the system. For example, a leak in landing gear actuator system might bleed the entire system - rendering the whole hydraulic system inoperable.

An isolation valve may also be used to prevent system operation if certain conditions are not fulfilled. Say, if airspeed is above a predetermined limit, the isolation valve would remain closed preventing the operation of the gear.


Is ATIS information - including identifier - available on the internet?

The short and general answer is: No.

The ATIS is only a VHF recording, but even when recorded digitally, it is not available in a text-base form in many cases which would allow being made public on the internet. In the case of D-ATIS, the information can only be obtained using ACARS, other systems such as CPDLC require special equipment.

With modern technology and communication, some airports have started to use Twitter to broadcast ATIS, however they should not be used for flight purposes, but are only for entertainment.

(Image Source: Twitter - Account: @yssyatis)


Where can the FAA versus ICAO official filed differences be found?

The link you provide is for an amendment of the US AIP, not the entire document.

The entire document is available here: (link)

You will have to look at section GEN 1.7 (starts at PDF page 57).


How and why would one call the cockpit of an A330 inside its nose gear bay?

The fact it's called the MECH channel is a pretty big hint that yes, this is for maintenance personnel.

Ant it's not just the nose wheel bay, there are service interphone connections in several locations.


Are there airport identifiers assigned to heliports?

Generally, not all airports have an ICAO or IATA code. Helipads and small airports usually don't rank a code from either of them. IATA won't have any reason to assign a code unless there is some kind of passenger service out of them. ICAO won't have any reason unless there is some significant international service from there. There is more info on the criteria for ICAO codes on this question. Those helipads have FAA identifiers, though.

BSO Public Safety Helistop: FA10
Port Everglades: 2FD4
Broward Health Medical Center: 6FD8

FAA-only ID's have either three or four digits and always contain at least one number.

From the FAA's JO 7350.9K - Location Identifiers (p.1-2-3):

  Two−letter, two−number identifiers are assigned to private−use landing facilities in the United
  States and its jurisdictions which do not meet the
  requirements for three−character assignments. They
  are keyed by the two−letter Post Office or
  supplemental abbreviation (listed below) of the state
  with which they are associated. The two−letter code
  appears in the first two, middle, or last two positions
  of the four−character code.

There are helipads that have IATA and ICOA codes, though. For example, West 30th Street Heliport (IATA: JRA, ICAO: KJRA, FAA: JRA) in New York.


How do groundspeed and IAS change during eights on pylons, and how should I manage them?

Answering the easy question first:

No, you should leave the throttle alone once you've begun the maneuver.

As for the other question:

Without seeing your technique, I suspect your IAS is changing because of your climb/descent rate

I don't know how quickly you're climbing and descending, but if you're trying to hit specific speeds at various points during the maneuver, it's likely that you're going to end up flying mechanically and abruptly. An eight-on-pylon should ideally be flown with your eyes mostly scanning outside, and only occasionally coming inside to reference your altitude and speed.

If you're trying to hit pre-computed numbers rather than looking outside and keeping the pylon on the lateral axis through smooth application of the controls, then my guess is that you'll be climbing and descending more than you need to, and you'll be doing it more abruptly than you need to, which may lead to large changes in IAS.

Have a look at the Airplane Flying Handbook, page 6-17:

  With prompt correction, and a very fine control pressures,
  it is possible to hold the visual reference line directly on the
  pylon even in strong winds. .....  It is important to understand that variations in pylon position are according to the apparent movement of the
  visual reference line. Attempting to correct pivotal altitude
  by the use of the altimeter is ineffective.

(emphasis mine)

This part of the answer may be entirely incorrect, because I don't know what your flying technique is. If you can give us more information, we can give better answers.


Are compressor maps for multistage compressors drawn for one blade row or the whole compressor?

The image you are referencing is definitely an entire compressor.  You can tell because the pressure ratio axis goes up to 17:1.  You won't get 17:1 out of a single blade row, ever. One-tenth of that would be more likely for a single stage.  i.e. this could be a 10 stage compressor with each stage contributing a 1.3 - 1.4:1 pressure ratio.

I've only ever seen compressor maps like this drawn for entire compressors.  Not to say you couldn't do a single stage, but I've not seen it done.


Do pilots using an electronic flight bag need to carry paper charts?

A EFB is a legal replacement for paper charts and you are not required to carry backup if you are operating as part 91 single engine piston. Advisory Circular 120-76B is in reference to part 91F (Large and Turbine-Powered Multiengine Airplanes).

AC 91-78 is aimed at Part 91 operators, VFR or IFR and states that EFBs can be used in all phases of flight in lieu of paper.

A backup data source is suggested, but is not required. Note that this backup can be another electronic device.

See iPad Legal Briefing for Pilots.


Can the thrust of a turbofan be increased by increasing bypass ratio?

GE used the core of the F101 engine as the core of the CFM56 (with some modifications, presumably). The core of a turbofan consists of the high pressure compressor, the combustion chamber and the high pressure turbine. In this case, we talk about a 9-stage HPC and a single-stage HPT. Everything else was newly developed for the high-bypass turbofan.

Unlike just putting a larger fan on the low-pressure shaft, this is possible becasue the high-pressure components and the low-pressure components are relatively independent in a turbofan, i.e. the core of the engine is not affected too much by the size of the fan, the bypass ratio or other changes in the low-pressure area.

The new low pressure turbine (4-stage instead of 2-stage) can operate at a lower rpm and transmit more of the exhaust gas energy from the engine core to the larger fan (the exhaust gas coming out of the new LPT is probably cooler and slower than that coming out of the F101 LPT). The new low-pressure compressor increases the overall pressure ratio and therefore increases the amount of energy that goes to the low pressure compressor and fan, thereby improving the overall efficiency. This is probably possible because the non-supersonic operational envelope of the CFM56 means that intake air total temperatures will be much lower so that the same EGT margin can be achieved with a higher pressure ratio. In other words, becasue the incoming air is cooler, it can be compressed further without damaging the high-pressure turbine because it is too hot.

The static thrust of the CFM56 is 19500 lbf, which is up about 15 % from the F101's 17000 lbf without the afterburner. While a small part of this is probably an aerodynamic loss due to the unused afterburner chamber, most of it has to come from the better use of the energy offered by the engine core exhaust in the larger fan. The difference might even be higher becasue the maximum thrust of the F101 might be adjusted for a much lower mean time between shop visits. I'm not sure about that though.

This shows that the main benefit of the high-bypass low pressure section of the engine is a significantly increased fuel efficiency, an increase in the static thrust and (much) lower noise levels. The F101, on the other hand, can operate at higher speeds, produce more thrust at high speeds, is lighter and has a much smaller cross-section.

(Edited per comment by fooot, thanks for finding the source.)


Why doesn't GA aircraft use the JASC/ATA document standard?

Newer GA aircraft do generally follow this format like the SR22 service manual. As jamesqf mentioned in the comments many of the popular GA aircraft were designed upwards of 50 years ago and their airworthiness and maintenance procedures have not really changed a whole lot thus the manuals are sill what they were when published 50 years ago.

14 CFR § 23.1529 requires that instructions be drafted (or in the process of being drafted) during certification. Like anything in aviation once its certified, why rock the boat by re-writing the manual just to comply with a format.
More reading...


They do.

If you are clearly not physically able, they will change your seat during check-in.

Then, as part of the safety briefing, you will be explicitly asked if your are willing and able to carry out the relevant instructions.  If you are not, the crew has the authority to re-seat you.

If all passengers are seated, and no-one is in the exit row, the crew will re-seat a capable person next to the door.

Here's but one reference to the requirements from the UK CAA.