Is it ever allowed to list your destination airport as the IFR alternate too?

You would never list your destination as an alternate (that wouldn't logically make sense), but there are situations where having an alternate is not required:

At least one destination alternate aerodrome must be designated and specified in the both operational and ATS flight plans if a flight under IFR is going to be made unless one of the following applies:

after taking all relevant factors into account, it is reasonably certain that VMC will prevail for the approach and landing and there is more than one independently useable runway available which can be expected to be useable at the ETA and at least one of those runways has an instrument approach procedure

the aerodrome is isolated, in which case a destination alternate is not required and instead additional fuel must be carried. a Point of No Return (PNR) must be determined and this must not be passed unless an assessment of the prevailing weather, traffic and other operational conditions indicates that a safe landing can be achieved at the ETA.

Source: https://www.skybrary.aero/index.php/Alternate_Aerodrome (ICAO Annex 6 Chapter 4)


Does a Boeing 737 NG have Air Data Modules for the standby Pitot probe and static pressure port?

Standby instruments provide a critical backup function and are totally independent from the primary air data system. The dedicated standby probes are connected directly to the standby display unit which is capable of converting the pressure inputs into airspeed and altitude. They only require a 28V DC input from the EMER/BATT power bus to operate.

Here's the description diagram from the Boeing maintenance manual:


What is a simple way to explain why best range airspeed is below normal cruise airspeed?

Normal cruise is a compromise between being fuel efficient while getting to your destination at a reasonable speed.  It all comes down to drag; the faster you go the more parasitic drag you pick up and economy suffers.

Just like in your car - if you wanted to squeeze max efficiency (range) out of a trip you could drive at 55mph on the freeway.  In fact you could even make it law!  But, people are generally willing to burn a little more fuel to get there faster.


Is a cIearance only valid once it's accepted?

Interesting question - although not FAA, I hoped the UK's CAP 413 would hold some insight as it tends to follow ICAO rules:

https://publicapps.caa.co.uk/docs/33/CAP413%20MAY16.2.pdf

Page 25 is the relevant chapter, and while it doesn't outright say the clearance is not valid it is very strong in its readback requirements. The following language applies to runway entry/take off/landing:

  The stringency of the read back requirement is directly related to the
  possible seriousness of a misunderstanding in the transmission and
  receipt of ATC clearance and instructions. ATC route clearances shall
  always be read back unless otherwise authorised by the appropriate
  ATS authority

  The ATS messages listed below are to be read back in full by the pilot/
  driver. If a readback is not received the pilot/driver will be asked to do
  so. Similarly, the pilot/ driver is expected to request that instructions are
  repeated or clarified if any are not fully understood.

  [Lists the relevant activies, including runway entry]

It also points to ICAO Doc 4444:

https://ops.group/blog/wp-content/uploads/2017/03/ICAO-Doc4444-Pans-Atm-16thEdition-2016-OPSGROUP.pdf

With similarly direct wording:

  The flight crew shall read back to the air traffic controller safety-related parts of ATC clearances and
  instructions which are transmitted by voice. The following items shall always be read back:

  a) ATC route clearances;

  b) clearances and instructions to enter, land on, take off from, hold short of, cross, taxi and backtrack on any
  runway; and

  c) runway-in-use, altimeter settings, SSR codes, level instructions, heading and speed instructions and, whether
  issued by the controller or contained in automatic terminal information service (ATIS) broadcasts, transition
  levels.

It seems clear to me that ICAO, EASA and CAA standpoint is that readbacks are completely mandatory, and the clearance has not been fully delivered until the readback is completed. The readback is a controller final opportunity to correct a potentially critical misunderstanding or communication and it seems to me that proceeding without reading back, and waiting for any call of "Negative" is negligent.


Has a civil aviation accident ever involved more than two manned aircraft?

The Rammstein Airshow Disaster comes to mind, where one airplane of the Italian Air Force display team collided with 2 others during a display, so 3 airplanes were involved in the collision in the air. A medivac helicopter on the ground was also destroyed, which was manned at the time, fatally injuring the pilot.


Does a flight briefer require a license in the US?

I imagine that the do receive plenty of training and I belive there was a time where they were "Flight Service Specialists" (this may have changed when LM took over). The FAA offers a great free course through their WINGS program on Flight Briefings and how they work on the other side (from the briefers stand point). I attended it recently and I recall that the woman giving the course was a former briefer and was a Flight Watch Specialist. I don't recall if that was a requirement or not thought (you can always reach out to her and ask). It should be noted that Flight Watch/Lockheed Martin Flight Services are now run by Lockheed Martin on contract to the government and are no longer run solely by the government as they once were, which may have changed things operationally (I have only ever known it in its current state).

As for staying on top of things, in todays modern times that is more the job of a computer than the briefer. Things like NOTAMS and AIRMETS/SIGMETS in route are given to them digitally once you tell them your course/route. There was once a time when this would have been a manual process but those days have long since passed. In my general experience flying VFR on a longer flight the briefer will not give you all the radio outage NOTAMS up front but will ask you if you "want to hear the radio nav aid notams" or something like that. They will give you things with in a certain distance from your planned route or if you ask for it. For example you can say "is VOR XXX in service?" and they will look it up for you.

Other Notes:

There is an interesting discussion on the day to day here.
You can read up on the history here.
And this Article


In an F-18, how do rudders deflect during cross winds and gusts? Can rudders be deflected by different angles?

The Hornet has a fly-by-wire flight control system that is run by 2 flight control computers (also known as Roll Pitch Yaw computers) and these each have 2 channels. This system gets pilot input from the controls but the computers will decide the most efficient way to impart the command signal using all of the available control surfaces. Pilot has no say in which surface moves. If they did, this aircraft would be a nightmare to control because, like most modern fighter jets, it has been designed to be inherently unstable. This allows it to be highly manoeuvrable during a dogfight.

Some of the surfaces are controlled by 2 channels (rudder, aileron, leading edge flaps). Some are quad redundant, utilising all 4 channels (Trailing Edge Flaps, Horizontal Stabs).

All of the surfaces, with the exception of the leading edge flaps from memory (because they are connected mechanically with a rod???), can deflect independently of each other, if the software/flight envelope permits. For example, if you want to roll a Hornet, some combination of all or some of the following surfaces may deflect: L and R Aileron, L and R Trailing Edge Flaps, L and R Horizontal Stabilisers. There are various sensors such as accelerometers which provide the negative feedback loop required to ensure the aircraft is getting to the required attitude at the expected rate. If it isn't, surfaces may deflect more or others may be commanded to help out. The circuitry inside the computer is basically a summing amp with the following inputs: command signal from the pilot, the position feedback from the surface and the rate feedback from the accelerometers. I think the important thing to understand is that this signal is nulled (0 volts) when the aircraft is pointing in the commanded attitude. That means no more movement of the surface.

With regards to rudder on takeoff, these accelerometers would sense an uncommanded change in the yaw axis and I suspect the flight control computers would damp this affect using the feedback method described above without the pilot really noticing much, certainly not having to stomp on a rudder pedal to compensate. There would be some sort of signal processing delay and mechanical reactive delay to correct the movement but this is all done without pilot input.

The rudders don't have to deflect symmetrically as they are controlled by different flight control computer channel pairs, one from each computer for redundancy. In fact, when the rudder fails, it is commanded to streamline and the other surfaces will compensate. The software programming inside the flight control computers that determines which surface/surfaces move and by how much.


What is acceptable visual cue at Decision Height when performing CAT II approach?

Short answer: for CAT II, seeing the approach lights (minimum 3 segments) is sufficient given a lateral element is also acquired.

Visual acquisition definition may vary between FAA, EASA, ICAO, etc. What follows is for EASA (as tagged).

For CAT II, you may descend below the DH if you can see:

3 consecutive approach lights,
or touchdown zone (TDZ) lights,
or runway centerline lights,
or runway edge lights,
or a combination of the above,
and must include a lateral element, i.e., crossbar, threshold, or TDZ pattern lights.

(Source: Airbus) A crossbar plus 3 segments.

For CAT IIIa and CAT IIIb (fail-passive; no roll-out mode):

The same as above, minus the lateral element.

For CAT IIIb (fail operational; roll-out mode):

At least one centerline light is attained and can be maintained.

Do not use for flight.


What are the benefits of long-haul airplanes servicing regional routes?

TL;DR You're confusing concepts, planes come in high/low capacity and range, routes come in high/low demand and long/short haul distances. A high capacity long range aircraft can operate very profitably on a short haul, high demand route... a full 747 would actually be more profitable on a 1000km route than a full 737, because although the 747 uses more fuel, it also carries a lot more passengers.

You're assuming that putting a big plane on a short route wastes money. Airlines don't work in miles per gallon like you or I do with their car... they work on income/expense. I could fly 747s on 100 mile hops all day, but if they're full of 400+ passengers each paying more than 0.25% of the running costs of that flight, I'll still make money.

If they could have used a smaller aircraft, it might waste a
little money carrying the extra weight, but you seem to be
over-simplifying things

I'm guessing this question is actually more along the lines of "How often do airliners run an aircraft that isn't completely full, and how much of that time could they have actually run a smaller aircraft?" To which the answer is "Usually, and not very often"
The economics are about running the whole system as a profit. If I have enough flights in summer that fill the aircraft, then over 12 months that bigger aircraft (highly profitable all summer, breaking even all winter) may make all money than a smaller aircraft making a small profit all winter, and a small profit all summer, but not being big enough in summer to take the entire potential demand.

Essentially, though, airlines are in the business of getting the "best fit" for their fleet. They aren't trying to get a plane in every size to have the perfect profit ratio for each flight, they are trying to get a suitable plane on each flight. This involves moving planes around as routes change etc. In an ideal world you'd run each plane exactly full of every passenger who wanted to fly on that route. In reality, we probably want a plane which is just slightly bigger than that, to cope with the small amounts of extra demand
Again you're seeing "Long haul" and "Short haul" aircraft as different concepts. They aren't. There are only high/low capacity aircraft and high/low capacity routes. Long haul routes tend to have less frequent service with larger, higher capacity aircraft (if you're travelling for 18 hours, you don't need a service with departures every 3 hours). They also tend to involve people travelling from "The UK" to "Australia" for example, so one big plane can cover all of that, and split to smaller aircraft to disperse them

Short haul routes tend to have more regular service and smaller
demand levels, partially because people are less likely to want to depart at the same time every day, and partially because they can be more fine grained - you can go from an area of one country to an area of another.

What you seem to miss is that these things are not mutually exclusive... with enough demand, larger aircraft can run short haul routes very profitably. The fact a 747 is usually profitable on long haul flights, and the fact the demand on short haul routes do not usually have enough demand for such a large aircraft, don't mean that one could never be profitable if enough people wanted to fly on it. There are airlines using 777s for example for fairly short haul journeys, very profitably, all over the world.


When has a pilot legally accepted an ATC clearance or instruction?

I would try to not over complicate this issue.  There are three conditions a clearance/instruction can have:

Transmitted/Received
Accepted
Rejected

If ATC provides a clearance/instruction, but has not yet received a response, the clearance/instruction has not been accepted or rejected.

If the pilot acknowledges the clearance/instruction with a read-back or affirmation of understanding, then it is accepted.

If the pilot responds with the term "unable" to any element of the clearance/instruction, then the entire clearance/instruction set is rejected, which may prompt ATC to inquire as to why the clearance/instruction is being rejected or to provide a different clearance/instruction.

Per 91.3 the pilot-in-command reserves the right to act as the final authority as to the operation of the aircraft, but once a clearance/instruction is accepted, it is an indication that the pilot-in-command is agreeing, as the authority of operation, to operate by that clearance/instruction until released from it or forced to deviate due to an emergency or TCAS alert.

One note for safety: to be clear, one cannot simply reject one element of a clearance/instruction without rejecting the entire clearance/instruction.  For example, if ATC issues a turn and a climb, but the pilot's aircraft cannot or may not climb higher for whatever reason, the pilot should not read back the new heading and say, "unable climb," and then turn to the heading and wait for more instructions.  What if the climb is to avoid obstructions that exist on the new heading?


Do "Civil Aviation Regulations" and "Aeronautics Bulletins" still have any legal authority today?

No, except for a type certification rule.

  Aug 23, 1958:

  President Eisenhower signed the Federal Aviation Act of 1958 (P.L.
  85-726) into law. Treating comprehensively the Federal role in
  fostering and regulating civil aeronautics and air commerce, the new
  statute repealed the Air Commerce Act of 1926, the Civil Aeronautics
  Act of 1938, the Airways Modernization Act of 1957, and those portions
  of the various Presidential reorganization plans dealing with civil
  aviation.

The aviation law slate was wiped clean and started fresh with the FAA, although many of the principles in the aeronautical bulletins and the Civil Aviation Regulations were clearly incorporated into the FARs we know today.


Did/do any commercial passenger aircraft have showers for passenger's use?

On Emirates or Etihad long haul flights, they do have showers available only to certain passengers. Here you can find a link to an article about the showers. After those two airlines, as for inflight showers go, I do not know of any other inflight showers.
The 777 has inflight showers as well. The airline can request the systems necessary to have the showers. So technically any plane can have it.


Why do new engines have a case with a triangular tiling pattern?

This type of structure is called isogrid structure. Solid walls are usually very heavy and therefore engineers use more weight-efficient structures such as sandwich structures or stiffened structures with stringers and frames. A downside is the huge manufacturing cost compared to other options.
As you can see from NASA Report CR-124075 "Isogrid Design Handbook", which was written 50 years ago, it is not a new type of structure.


Was the adoption of conventional tailplanes as 'everyday aircraft' inevitable, or are there other designs that can be just as good?

If you write an optimizer which modifies the wing spans of a virtual aircraft, you will end up with a big wing in the middle and a smaller one at the tail if your goal was to achieve good performance, a wide cg range and docile behavior. So yes, a concurrent evolution would also result in a conventional layout.

Why no canard?

The forward wing is more highly loaded for stability. Adding control surfaces there would reduce the possible control effectiveness. Putting them at the large rear wing will result in higher stick forces and higher lift changes for the same pitch moment changes.
For the same reason, the wing cannot utilize its full lift potential because the canard has to stall first.
Since the wingspan of the canard is smaller than that of the wing, the wake of the canard will hit the wing and disturb the lift distribution over span there.
For directional stability a tail is still needed, even though it is only used for vertical surfaces. Alternatively, the canard wing can be swept and winglets be used for directional stability, but adding sweep will reduce the efficiency of the wing.

This all puts the canard at a distinct disadvantage. It works, but comes at a price.

Why no flying wing?

Flying wings have low pitch damping and a very limited center of gravity range.
They often cannot have trailing edge flaps for extra lift during slow flight, so their take-off and landing speeds are higher than those of a comparable tailed aircraft. Or the wing loading has to be made lower, which hurts at high speed.
Even though a good flying wing design has sweptback wings, they are poorly suited to high transonic speeds. Their wing airfoils cannot have rear loading, so the critical Mach number at the same lift coefficient is much lower than for conventional configurations.


What are the requirements for logging SIC time?

You can basically log SIC time if you are a required crewmember and are not able to log PIC time.

So, generally in an airplane like a C-182 which is certified for only one pilot, you can't log SIC time because you aren't a required crewmember.

There are a few exceptions though, like being a safety pilot for the PIC while they are using a view limiting device (like an IFR hood), etc.

SIC time is not pointless because it still adds to your total time!

As far as landings, you can log them only if you are the sole manipulator of the flight controls, in which case you are allowed to log PIC time (even though you aren't allowed to act as the PIC since you don't have your high performance endorsement).  Oddly enough, in this situation the pilot who is acting as PIC isn't allowed to log it because they don't meet any of the requirements for doing so. It's one of the only situations where the PIC isn't allowed to log it as such.


How can the required wing area for climb be calculated, given aspect ratio?

Let's start with 3.19, since you need the result for 3.20. The parameters given suggest that we should calculate drag $D$ with the parabolic formula $$D = \frac{\rho}{2}\cdot v^2\cdot S\cdot\left(c_{D0} + \frac{c_L^2}{\pi\cdot AR\cdot e} \right)$$
I haven't seen the symbol $R_A$ before, but its magnitude suggests it is the aspect ratio (normally $AR$ in the US, $\Lambda$ elsewhere). Since the whole is an optimisation problem (we look for flight with minimum power consumption), we can determine the lift coefficient $c_L$ already. For propeller aircraft the point of minimum power is when the lift coefficient is $$c_L = \sqrt{3 \cdot \pi \cdot AR \cdot e\cdot c_{D0}}$$
Hey, you know all terms already! This allows you to proceed to the wing area once the needed lift is known. My next heroic assumption is that $W$ actually denotes a mass (the unit seems to say it is pound-force). The power plant should weigh 100 - 150 lbs already, so 200 lbs for the whole aircraft seems reasonable. So you can proceed:
$$L = 200 lbs \cdot g = \frac{\rho}{2}\cdot v^2\cdot S\cdot c_L$$
Plug in what we know, use sea level density ($\rho = 1.225 \frac{kg}{m^3}$) and the previously calculated lift coefficient:
$$S\cdot v^2 = 1527 \frac{m^4}{s^2}$$
This gives you pairs of wing area and speed squared which together fulfil the requirement. Some pairs, though, make more sense than others. Generally, the biggest wing will need the lowest power but will become increasingly fragile as wing area increases.

But there is still one requirement left: We cannot use more power than those 0.33HP:
$$P = 0.33\cdot0.7 HP = 172 W = D\cdot v = S\cdot v^3\cdot\frac{\rho}{2}\cdot0.04$$
$$\rightarrow S\cdot v^3 = 7094.8 \frac{m^5}{s^3}$$

Both conditions can be fulfilled when the flight speed $v$ is 4.646 m/s. This makes the wing area $S$ = 70.735 m².

Solving this for Denver, CO and finding the climb speed with 0.6 HP of power should be easy now. Just calculate the SEP and you know the climb speed.


Why must the long cross-country flight for a commercial rating be solo?

I got this answer to my question from a CFI...

The idea behind the solo requirement is to assure the pilot can accomplish the trip unassisted. Other passengers are permitted if an instructor is present because the instructor will assure that the passengers do not assist with the flight.


Why can't blimps be economical for commuter / public transportation?

I'm guessing that it would absolutely be possible to make blimps economical. The question is whether it would be better than alternatives.
For public transportation, there are a number of common alternatives:

Buses. Low-to-medium throughput, relatively low speed, short distance, very high flexibility.
Trams. High throughput, relatively low speed, short distance, high flexibility.
Metros. Very high throughput, medium speed, medium distance, medium flexibility.
Planes. Medium throughput, high speed, long distance, medium-to-low flexibility.
Ferries. Medium throughput, relatively low speed, situational (i.e. water connections).

(There's also regional coaches and trains, which are the big brothers of buses and metros. Omitted mostly for brevity.)
The challenge for blimps would be to out-compete any of these other forms of transportation. It would be impossible for a blimp to cover the very high throughput offered by metros or trains, or the flexibility of buses. For larger distances, planes are much faster and are not nearly as affected by weather. They also have the benefit of trained personnel/drivers (mostly) readily available, more infrastructure, production and we know that they work. Plus you don't have to change people's habits, which is hard.
In short, there is nothing a blimp could offer that isn't already covered by better alternatives. Except maybe a nice view on a sunny day.


Can an F-16 fly with conventional hydraulic powered controls without a computer controlled Fly By Wire System?

I did some searching and got an extremely interesting answer here:
By the way, I should have worded my question differently :  the F-16 does have hydraulically powered controls, but the pilot inputs are sent through a computer first.

  They designed the plane so it could be fitted with conventional
  hydro-mechanical controls if the fly-by-wire system couldn’t be made
  to work acceptably. “We spaced the bulkheads so that we could move the
  wing back and have a statically-stable airplane,” says Hillaker. “We
  were just giving ourselves some insurance. The wing would have had to
  have been moved back eighteen inches. All we had to do was make the
  two bulkheads have the same load capacity. One of them that we
  would’ve moved the wing to was higher than it needed to be, unless you
  moved the wing back.”  The structural differences carried over to the
  production F-16 design, but fortunately were never needed. The
  fly-by-wire system’s control problems were quickly ironed out and the
  plane, even with all its advanced features, steadily gained support
  both in the U.S. and abroad

So model makers note: get the CG for the F-16 and move it back 18 inches or whatever the equivalent is on your model for a stable airplane.

http://www.f-16.net/articles_article13.html


What prevents fighters from being fitted with jetliner-style bleed-air wing anti-ice?

Most fighters have enough thrust to power through icing conditions, so anti-icing or heat is limited to inlet(s) and pitot probe(s). That said, at least one F-16 flight manual, to use one example, says the following about flying in known icing conditions:

Flight in areas of icing should be avoided whenever possible. If icing
conditions are anticipated or cannot be avoided, turn ANTI ICE switch
to ON and PROBE HEAT switch to PROBE HEAT. Frequently check the
aircraft leading edges for indication of ice buildup. Make all
throttle movements slower than normal when in potential icing
conditions to reduce possibility of engine stalls and/or stagnation.
Consider diverting to an alternate field if required to avoid icing
conditions.

The F-14 also had the same systems, engine inlets and pitot probe heat. No other anti-icing systems on the aircraft.


What are the types of these 3 single-engine aircraft and one Multi engine aircraft?

The upper left one looks like a Fairchild PT-19-family monoplane trainer. Production on these started in 1939 and served through the end of the war as a basic trainer. Yours might just be the PT-19B variant, which has a hood over the front cockpit and was used for instrument training:

The upper right one looks like a Vultee BT-13 or BT-15 "Valiant" basic trainer, which were used as Air Force and Navy basic trainers from 1940 to 1944:

The lower left is actually a twin-engine plane, not a single, looks like a variant of the Beechcraft Model 18, or "Twin Beech". These were built beginning around 1937 and continued well into the Vietnam years. Military designations include the C-45 Expeditor, AT-7 Navigator, and AT-11 Kansan, but your specific example appears to be civilian:

The lower right is a North American T-6 or AT-6 Texan. Production on these began in 1933 and they were only retired from all air forces in 1996 (though the last operator, South Africa, only kept them as basic trainers because a military embargo related to its Apartheid policy prevented them buying anything newer):

As far as exact build dates of these aircraft, you might be able to look up the tail numbers of each airplane, but these craft were so common and so varied during their production that exactly when a specific airframe was built is difficult to determine by looking at it. All of these aircraft, in addition, seem to have been "civilianized" after service with the USAAC/USAAF, so their full history may be very hard to trace without their logbooks.


What protection did the Concorde have against an uncontrolled decompression?

This is the main reason why Concorde had such small windows. It was calculated to reduce the rate of decompression to a survivable level in case one window fails. (The prototype, by the way, had much larger windows).

Other than that, I don't know of any other 'special' decompression mitigation measures that would be unique to Concorde.

There were, of course, things that had to be done in a very special manner on Concorde in case of decompression. For example, rapid emergency descent: there was a special program that transfered fuel forward during emergency descent. It could be activated by a single button, and the flight engineer had to keep the program up to date for the current flight conditions. (Generally, keeping the CG/fuel balance was pretty much a full time job for the Concorde flight engineer). But this would hardly help in case of 'uncontrolled' (explosive) decompression.


How does one tell whether a corkscrew approach is stabilized or not?

The corkscrew approach as Wikipedia describes it is what the military refers to as a “Force Protection” measure to be used when operating in a high threat environment.  It is not a published procedure in the traditional sense of the word, but something that is put in place by the theater commander and briefed to aircrews when driven by the current intelligence assessment of the threat level.

It is not intended to be flown as a precision maneuver like an instrument approach would be.  It is a dynamic, eyeballs outside the cockpit looking for a missile, combat visual descent.  A high rate of speed is maintained until as late as possible in order to make evasive action possible.  Not only is it clearly NOT a stabilized approach, it is actually the exact opposite:  Done in VFR conditions, the aircraft isn’t configured until just before landing.

Contrast this with the definition of a stabilized IFR approach from FAASafety.Gov below:

  Stabilized Approach Concept. A stabilized approach is one in which the pilot establishes and maintains a constant angle glide- path towards a predetermined point on the landing runway. An airplane descending on final approach at a constant rate and airspeed travel in a straight line toward a spot on the ground ahead.

There is a lot of additional information available about stabilized approaches out there for anyone interested so I won’t attempt a further explanation about the intent.  By definition, however, a corkscrew approach is not stabilized.

So, back to the original question:  “How does a pilot performing a corkscrew approach make this determination?”  (whether the approach is stabilized or not…)  The answer is that a pilot performing a corkscrew approach isn’t asking himself those kind of questions.  The distinction is completely meaningless.

He/she is looking outside for the smoke trail of a stinger rising from the ground, and working to get the plane to a point where they can pull the nose up to break the rate of descent and slow down, slap the gear and flaps down, and make a tight 180 combat turn to a short final to lessen the exposure time when they are dirty and slow.  The goal is to get on the ground as safely and expeditiously as possible and minimize any time spent “stabilized” on a long straight-in approach.

Stabilized approaches are what tactical aviators fly stateside when practicing for their annual instrument proficiency check.


What are the requirements for an aircraft to be allowed to perform fast taxi runs?

Regulation wise, no, there are no regulations which have to be met to conduct a high speed taxi test.  All that's needed is an aircraft with the capability to accelerate to speed and stop as well as a runway long enough to do it on.  If at a towered field, you'll have to get a clearance to do this.

It used to be mechanics would take aircraft freshly out of maintenance out for high speed taxi tests to verify the work was done right.  One such high speed taxi test went ary for a USAF mechanic named George Johnson in 1956 and earned him his first - and successful - solo at night in an F-86!


What is the meaning of the letters on the side(s) of WWII British aircraft?

Spitfires had a few different markings, but primarily there were two. One, written in smaller, often black, text was the aircraft serial number and stayed with it for its entire life. The other, usually either side of the roundel was the squadron and airrcraft id:

Image source

XT was 603 Squadron. So if a Pilot of that squadron was told to go and "Fly Delta" he would know to go to that specific aircraft. Aircraft would have been lettered in sequence, Alpha, Bravo, Charlie etc.

There were some exceptions; to wit

  ...Thus the famous Douglas Bader was allowed to have the letters "D-B" painted on the side of his Spitfire VA, because he commanded the Wing flying from Tangmere Aerodrome. Bob Stanford-Tuck, commander of the Biggin Hill Wing had a Spitfire with "RS-T" on it.
  source

Hurricanes followed the same standard


How do I calculate the aircraft's deviation from track in this exam question?

Pretty easy... You are 225° QDM, the track was 245°. Neither QDM nor MKK is nothing about variation or deviation, because both of them are magnetic (i. e. variation already applied) courses (i. e. not heading, therefore deviation is also not an issue).

20° deviation from track at 30 km to the station gives us 30 * sin(20°) = 10.26 km, i. e. approximately 10 km. Our QDM is less than desired track, and we are moving to the South-West, so we are to the North-West of our desired track, i. e. we are on the right side of the desired track. Therefore, the answer is 1, right of track 10km (5.4 nm) (Nk=+10km).


Why does British Airways fly a short haul flight in a B767?

Aircraft selection for a particular route is quite complex, especially for a large airline that operates many different types of aircraft.  You're correct: generally speaking widebody aircraft are used for longer flights, but there are a number of other factors at play.  Some of these could be that a route has a very high peak demand, where a lot of people want to go from A->B at a given time.  LHR to Edinburgh seems particularly likely to be one of these city pairs.  Sydney to Melbourne is another one, and is only about 400 miles if my memory serves.  In both of these cases there is a dominant national airline in the mix (BA, Qantas) whereas in the USA there are almost always 3 or more large airlines operating any heavy route (New York to Boston, or Washington DC to Chicago, etc).

Aircraft scheduling also plays a role.  For example, the 767 in question might be scheduled to fly from Heathrow to Edinburgh and back in the morning, before picking up a long-haul flight to the USA in the afternoon.  If there's a 4 hour "gap" in the schedule for that particular aircraft, it might make more sense for the airline to run it as a short out-and-back rather than have it sit on the ground at LHR.

Also, Heathrow is notoriously busy, and getting a takeoff/landing slot there is extremely expensive.  The high landing fees are charged at least partially regardless of the size of the aircraft, so there is some economic motivation here to divide those fixed costs by a larger number of passengers.

As another data point, I checked the daily schedule between Haneda (the main domestic airport in Tokyo) and Hiroshima (~400 miles away) and found the following list of flights:  9x 737, 4x 787, 2x 767, 2x 777 - so in this case you have almost half the flights on widebody aircraft, and probably closer to 75% of the total seats.

It's also entirely possible (I haven't checked the schedules) that this 767 run is temporary, due to a period of peak demand or at a point in the year where the demands on that aircraft type are lower elsewhere in the route structure.

So in summary: it's very hard to know all the reasons that a flight might be operated with a specific type.  You need to know a fair bit about the economics of the city pair, the fleet makeup of the airlines, the likely competition for the route, how the route timing interacts with other flights, the congestion level of the airport, and a lot of other things.


Is emergency floor lighting fluorescent?

Fluorescent (more specifically phosphorescent as the re-emission of absorbed light happens on a longer time scale) plastics are sometimes used for exit indicators as they're better than nothing when every other system fails, however they have some drawbacks that limit their usefulness, and so they're not relied on as a primary source of emergency illumination in aviation:

They're not very bright. Even a battery-backup 5-watt incandescent provides more light, and when passengers are trying to find the exit through a cloud of smoke from an engine fire, bright saves lives.
They lose brightness quickly. Here are samples of zinc sulfide on the left and strontium aluminate on the right of each picture. The first picture is immediately after the light source goes out. The second is after just four minutes of darkness:

They rely on external light sources illuminating them for a minimum time. On night flights (when luminescent exit indicators would be most needed), the cabin lights are often dimmed, reducing the effectiveness of photoluminescent strips. Passenger garments overlapping the strips, such as skirts or waist-tied jackets, will have a similar effect on individual strips.
Most pigments react most strongly to UV light which is undesirable for most other purposes. UV light is invisible to us so it's wasted energy, and it yellows plastics (such as cabin trim) which ages airliner cabins more quickly. Light sources that minimize UV are preferable for any purpose except for "charging" photoluminescent strips.
They can't be turned off. When cabin lights are dimmed for passenger comfort on a night flight (letting people sleep etc), the photoluminescent strips will make the cabin look like a cheap Halloween party for up to ten minutes after.

In short, there are better options, especially now with white LEDs that are more efficient and less of a fire hazard than incandescent lights. A simple lithium button battery in the same assembly as the light could keep a 50-lumen LED array going more than long enough even in a complete electrical failure, and LEDs bright enough for this purpose are becoming ridiculously cheap thanks to advances in LED lighting for homes and businesses.


What flaps and throttle settings are used on takeoff, climb, cruise, descent, and landing?

The exact numbers vary for each model of aircraft, so the FAA et al can't provide direct guidance; regulations just say to operate according to the manufacturer's specifications and procedures.

Still, that's not too helpful, so I'll give answers for the C172, which is one of the most common light planes. Other models will vary somewhat but likely follow the same general theme.

Short takeoff: 10° flaps, full throttle
Normal takeoff: no flaps, full throttle
Climb: no flaps, high-full throttle
Cruise: no flaps, mid-high throttle
Descent: no flaps, low-mid throttle
Landing: 30°/40° flaps, idle throttle

For the ranges, it's important to note that the pilot doesn't set the throttle to a particular position per se; he/she adjusts it as needed until the desired performance (or for cruise, economy) is achieved.


How is a Flying-V more efficient than current fuselage-over-wing designs?

I always ask myself the same question when I read such claims. Only that I am concerned about the huge wetted surface - frontal area is less of a problem here.

When I get hold of such studies, they invariably use projected future technology and compare that with current standards. As you correctly observe, most progress in fuel consumption over the last half century has been due to better engines with higher bypass ratios. Improved aerodynamics contributed maybe 30%, helped by higher aspect ratios and better surface quality made possible by using composite structures.

Another trick: BWBs (Blended Wing Bodies) with their wide fuselage are assumed to need less time for embarking and disembarking of the self-loading cargo. That will make them more productive but the complication of emergency egress from this wide fuselage (remember - all on only one side, within less than 90 seconds!) are waved aside. Also, structural penalties for a flat pressure vessel are assumed to be ridiculously low, so the BWB is even claimed to be more efficient structurally. Which it is, if you look at the spar weight alone. But skin surface area has weight, too -  but not in those studies.

What also helps is to fly more slowly. That improves engine efficiency especially with high bypass ratio engines and allows thicker airfoils which certainly are needed in order to spread passengers over more than half of the wingspan. What is saved on the ground is then used up in the air, and the result is indeed a more efficient operation. If we were not bound by that magic number of Mach 0.85, new designs could indeed be more efficient still.

Remember that the A380 also was claimed to be 20% more fuel efficient? After being overweight (no wonder if scaling laws are observed, something the base of this claim conveniently forgot) what is left of that claim today? In reality, the competition uses the same technological progress and the comparison has to be made on a level playing field, with real data. Then those claims quickly collapse.


Are there international standards to Air Traffic Control procedures similar to US standands?

ICAO Annex 11 "Air Traffic Services" is probably the top document. Implementations in national law might vary.


What happens to the control systems of a BAe 146 when the aircraft runs out of fuel?

is there any way to control the aircraft when it's out of fuel?

Yes

  Does the APU run on a separate tank?

No.

  Can the engines be windmilled for power generation?

Yes.

Control

Pitch and roll can be controlled mechanically.

The rudder needs hydraulic power - which can be provided from the emergency DC battery via a pump if the systems are configured appropriately for this by the pilots.

There is a magnetic compass and a minimal set of other instruments powered by the emergency DC bus.

Fuel / Generators

The four engines, including the two with generators, each have a separate feed tank that is fed from the main tanks.

When fuel stops reaching the feed tanks, warnings are shown/sounded in the cockpit. I vaguely recollect the feed tanks may have something like 20 mins fuel (could be less).

The APU is fed from the same main fuel tanks as the main engines.

Electrics

The electrical system has three modes

normal
essential
emergency

I believe that there is 30 minutes electrical power available from the emergency battery that powers the EMERG DC bus. There is an inverter that takes power from EMERG DC and provides power to the EMERG AC bus.

RAT

An overview schematic (allegedly for 146) does not show an emergency ram-air-turbine (RAT) generator.

Hydraulics

There are two Hydraulic systems, yellow and green. Each powered by a separate engine.

There is a DC pump that provides hydraulic power to the yellow system from EMERG DC power. There is a switch in the cockpit to control this.

Windmilling

A limited amount of hydraulic power can be generated by windmilling the engines but the pilots have to reduce the load on the engines by deselecting the standby generator.

One of the windmilling engines will be driving the emergency fuel pumps (obviously uselessly if you actually run out of fuel mid-air, rather than having problems with main pumps)

References

QualityWings flight simulation manual :-(
satcom.com


How to calculate the static pressure in a pitot tube?

The pitot tube is pointed into the airstream and measures the total pressure. Static pressure must be measured, not calculated. It is done so at a separate location, using a static port.

Both pitot tubes and static ports are needed in order to derive air speed, as this incident sadly illustrates.


Can Savannah be stalled with agressive yoke pull?

I have 500 hours in one, more or less... This one:

In my experience, if –with the engine at cruise, say 2/3 power– you start pulling the stick slowly, the machine does obediently pitch up, with no stall, but one has to be careful, and fast with the pedals. At the extreme, the airplane is pointing more or less to the zenith, and starts falling tail first while rolling, in reaction to the prop's torque. But it doesn't stall...
If you try the same gliding with the engine at idle, you won't be able to avoid a wing dropping down, more or less when the pitch reaches 30--40º...


Is it possible to start the engines while on push back?

Aircraft engines are started using the APU or a Airstart Cart. The GPU is for electrical power only and the engines are started off air power. It may be a Airstart was not available or they were running late on the block time and they blocked  using the APU to start the engines to make the block time. After engine start and before takeoff the crew will shut down the APU. Most US airlines start their engine off APU air unless the APU is not working then they will start off a Airstart Cart.


What happens if an engine fails between V1 and V2?

If an engine failure occurs above V1 the aircraft can accelerate to the Vr and take-off, retract gear and accelerate to V2 and pass the end of the runway at a height of at least 35 feet. From there, flying at V2 or above the aircraft can climb at angle that keeps it clear of nearby obstacles.

Part of the aircraft's certification is to demonstrate that this is possible.
This question is related to the exact requirements.

To determine the minimum runway length required, two scenarios are calculated. The first scenario has the aircraft accelerating to V1, suffering an engine failure at V1 and then aborting the take-off. This gives the Accelerate - Stop Distance Required (ASDR). The higher V1, the higher the ASDR.

The second scenario has the aircraft accelerating to V1, suffering an engine failure at V1 and then continuing the take-off. This take-off involves accelerating from V1 to Vr, lifting off, retracting gear while accelerating and climbing, reaching V2 and 35 feet at the end of the runway. The runway length required for this scenario is the Take-Off Distance Required (TODR). The higher V1 the lower the TODR. This because when V1 is higher the part of the scenario that involves accelerating on a single engine becomes smaller.

These calculations take into account aircraft weight, engine thrust, aircraft configuration and runway condition.

For the V1 that gives the same ASDR as TODR, the required runway length is shortest. This is called the balanced field length.

This video is an example of an engine failure between V1 and V2. While the aircraft is rotating the engine ingests a heron resulting in big balls of fire. The aircraft lifts of, accelerates and climbs away at angle steep enough to avoid obstacles.

Rejecting a take-off above V1 will likely result in a runway excursion.


Why do planes overfly Moffett Field before landing?

Moffett Field is a federal airport (requires permission) owned by NASA and has a wide ranging number of traffic patterns/approaches available.  In answer to your question, you may be seeing what is called an "Overhead" approach.  This is a VFR maneuver quite common at military bases and usually consists of the following:

Airplane approaches the runway in use at an altitude well above the airport (2000 ft AGL or higher).  Usually this initial altitude is higher than the downwind altitude.
At some point when over the runway (over the numbers, mid-field, departure end, etc.), the pilot will break left or right and enter a descending turn that will include a modified downwind length based on the point at which the overhead break occurred.
The pilot will then continue to a base leg and ultimately a final approach (often very short) to a landing or touch and go.
This maneuver is done under VFR as coordinated with, and cleared by, the Tower.

This type of maneuver could explain, based on your question, what you are seeing at Moffett Field.  See the pictures below.

From the Moffett Airfield Operations Manual:

Example Overhead approach: (just an example, many variations are possible)


Is an engine surge classed as an engine fire?

If the fire is momentarily and stops by itself: No, this is not an engine fire. Flames can come out of the engine at both ends in a compressor stall (also called surge - watch the movie which is linked in the question!), but that is no engine fire. See this question for another example where spectacular flames develop, yet the engine is not on fire.

If the fire can only be stopped by shutting off the fuel supply or the engine itself: Yes, that is an engine fire. I guess you refer in your question to this bulletin on PW4000s, where the No. 4 bearing overheated due to insufficient lubrication. In that case the oil itself overheated and burned, but this still makes it an engine fire.


What is a flight leg and why it is so important for an aircraft?

I don't think flight leg is important for either aircraft no airline.

The reasons why most flights have one or two legs is purely economic. Aircraft have to be operated with rather high load factor to be profitable. If you have a line with less passengers, you really want to use smaller plane or run it less often. Because different links have different demand, it's rather rare to have many consecutive links with similar demand so it would make sense to fly them with one plane as multi-leg flight. And few people would want to fly the whole trip as the stop-overs take rather long.

For aircraft what matters is not legs, but cycles, meaning pressurization cycles. For pressurized aircraft the material fatigue is most closely related to the cycles and since each cycle also involves one period of running the engines at high thrust, the engine wear is also somewhat related. It does not matter whether the aircraft accumulates 4 cycles in 4-leg journey or 4 separate journeys.


For large commercial aircraft, how are the tires changed?

In general, the jack is put under the axle of the wheel to be changed. Thus the oleo still carries the weight of the airplane and stays at the same extension, and the jack just has to lift the wheel far enough to be able to get it off the axle. Unlike a car, you don't lift the body off the wheel, you lift the wheel off the ground.


The term bogie initially meant (atleast in Britain) an assembly of wheels forming a pivoted support at either end of a railway coach, which provided flexibility on curves.

So, the term bogie refers to the set of wheels, rotating about the (landing gear) axis, while their arrangement- lateral or longitudinal doesn't matter.

An old patent for Bogie undercarriages for aircraft notes:

  ... a bogie having multiple wheel assemblies mounted on transverse rotational axes spaced one behind the other ...

The issue is that the term has been in use for a long time an has come to mean a number of things (even in railways, the entire carriage can be called a bogie)- so while the correct term is to call it a four (or six) wheel bogie rather than double or triple bogie, it is used quite often. Also, as I already noted, whether it is lateral or longitudinal doesn't matter as long as they are attached to the same (nose or main) gear.


In a full-rudder sideslip in a Schweizer 2-22 or 2-33 glider, is the descent rate higher at 50 mph airspeed than at 60 mph airspeed?

Full disclosure: I have exactly 3 hours logged in a glider and have never specifically flown the 2-22 or 2-33.
That said, I do have some experience and understanding of slips, and the principles should be the same.To answer your question, I will draw from quotes taken from this article on Boldmethod.com.

In a forward slip, the amount of slip, and therefore the sink rate, is determined by the bank angle. The steeper the bank is, the steeper the descent.

However, there will be a limit to how much bank angle you can introduce before you can no longer hold a constant ground track.

In light airplanes, the steepness of forward slips and sideslips is limited by the amount of available rudder, or the rudder-limit. You may reach a point where full rudder is required to maintain heading.

If you are already at this point, with full rudder deflection, maximum allowable bank, and a constant ground track, there’s only one variable left - Pitch. Pitching down increases speed and increases descent rate.

As you lower the nose, airspeed and descent rate will both increase. The additional airspeed will give your rudder more effectiveness, allowing you to increase the slip. The opposite is true of raising the nose.

This means that you are absolutely correct. Properly configured, a higher airspeed should give you a higher descent rate.


What is the difference between a nautical mile and a statute mile? And what is a knot?

According to the Encyclopedia Britannica a nautical mile used to be based on the curvature of the earth and was approximately equal to one minute (arc segment) of latitude along a meridian (longitudinal line running from north to south). The British nautical mile was set to 6,080 feet while the US nautical mile was set to 6080.20 feet. However, in 1929 the nautical mile was redefined to exactly 1.852 km (approximately 6076.11549 feet) at an international conference held in Monaco, although the US didn't make the conversion until 1954.

1 nautical mile = 1.1508 statute miles or 1.852 km.

A "knot" (speed measurement, not the kind you tie in your shoe laces) is equal to one nautical mile per hour.

1 knot = 1.15 miles per hour.


What is the working principle of anti-explosion fuel tanks?

Modern military fuel tanks use the same basic technology to seal the tank after a puncture as WW2 aircraft did, which is the use of a laminated rubber-textile material, which tends to retain its form after being torn. The main difference between modern tank liners and WW2 liners is that the modern liners use more sophisticated materials so they can achieve the same benefit using a much thinner liner (hence less weight).

Bullets hitting a tank do not cause "detonation" unless they generate a spark and the fuel-air mixture in the tank is in ignition range. Also, most aircraft explosions are not detonations, they are deflagarations. The liner does nothing to prevent this. The main functions of the liner are to prevent fuel from leaking out of a punctured tank and to maintain the integrity of the tank in a low-altitude mishap or crash. The main test for a liner is the "drop test" in which the liner is filled with fuel and dropped from a height of about 50 feet.

The advantage of pressurizing a tank with air (inerting) is that it increases the critical temperature of an explosive mixture. If the critical temperature of the mixture is above the ambient temperature, then the tank will not explode spontaneously when sparked. A modern variation on this is called "nitrogen inerting". The idea with that is to pressurize the tank with nitrogen. This makes the tank spark proof.

Note that inerting technologies do not prevent a fuel tank from blowing up if an aircraft is hit with ordnance. The reason for this is that typically the way an aircraft blows up is that damage from the ordnance starts a fire. The fire then rapidly evolves fuel-laden gases into open compartments of the aircraft. As soon as these gases reach the ignition mixture, the fire deflagarates the mixture, causing an explosion. Inerting does little to prevent this.

Inerting is very useful, however, because it can prevent a plane blowing up due to lightning or problems with electrical wiring or static electicity buildup.


why does it cost so much just for an hour of training?

You've not specified how much you consider "so much", however it's unlikely to matter too much to the answer. What you're paying for is (at least) twofold, and probably consists of

The rental of somebody else's aircraft. Every hour you fly this aircraft takes it an hour closer to an expensive maintenance window. There are costs involved in running an aircraft much like there are costs associated with owning/maintaining any vehicle. Also, fuel isn't free - its is often rolled in to the cost of rental for aircraft.
The time of an instructor, who himself has spent time/money learning his craft, and quite possibly does this as his job (as in, its his sole purpose to earn money from teaching you to fly). He has skill and experience, and like all jobs, the more his skill/experience the greater fees he can charge.

You may have missed the first rule of purchasing a service - shop around. Is your flight school/instructor of a comparable price to others in the locality? Is the instructor you're using a senior CFI, or a new CPL hour-building to get a job with an airline? You will potentially get a different level of service depending on price, but this may suit your wallet better while still giving you the skills you need to get your own pilots license.

Anectote: When I was training for my PPL (circa 2001-2002) in the UK I paid roughly £150/hr. This included the hire of a C152 and a pretty experienced instructor. From memory the instructor was £80/hr and the remainder was the aircraft. When I got sick of being cramped in a C152 with another 6'2" guy, I paid more to fly a C172 - probably added about £40/hr to the cost.


There is a hatch and a ladder in the bottom of the front fuselage, through which the pilots enter the bomber, as seen here:


Why is it advised to turn the aileron away from quartering tail-wind during taxiing?

The mnemonic that I use is, "climb into headwind, dive away from tailwind."

To address your question.

When the wind is a quartering tailwind, the tailwind component tends to want to lift the tail of the airplane, which could cause a prop strike or the airplane to be flipped over if the wind is strong enough. So by having the elevator all the way down, the wind hitting the tail will push the tail down instead of lifting it up.

The quartering tailwind hitting the trailing edge of the up-wind wing can lift the wing, so by diving away from the tailwind, the upwind aileron will be in the down position, which will help hold that wing down.

With regard to the physics of how this works, it has to do with the direction in which the wind is being deflected. When wind is coming from the front (headwind) an up aileron deflects the air up and pushes the wing down, but when the wind is coming from behind the wing, such as in a quartering tailwind while taxiing, the wind would catch an up aileron and lift the wing, so it is necessary to put the aileron down, so that the wind is deflected upwards thereby pushing that wing tip down.


What drives the compressor before the turbine provides power?

Turbine engines are spun up to idle speed using a starter.  This is typically in the form of an electric motor for smaller turbine engines and APUs and pneumatic powered starters for large turbine engines.  Once the gas core is spun up to a minimum speed, typically around 12-20% maximum core speed, fuel is introduced and ignited, causing a self sustaining combustion and the engine core spins up to its idle speed, typically about 50% - 60% maximum speed, before the starter cuts out.  Care has to be taken not to introduce fuel to the engine prior to reaching these speeds as the engine can overheat during startup and be seriously damaged (this is about the only disadvantage of aviation gas turbines).


An LAPL allows you to act as PiC, carrying passengers, but only in the type and variant you pass your test on.

  A LAPL for aeroplanes will allow you to act as pilot in command (PIC) on two classes of aircraft: either a single-engine piston aeroplane (land) or touring motor glider (TMG) with a maximum take-off mass of 2000 kg or less, carrying a maximum of 3 passengers, with no more than 4 persons on board.
  source

Whereas a PPL you will be able to fly all variants of SEP (source), with the exception that for things like taildraggers, and more complex aircraft (such as those with retractable undercarrige)  you will need extra training and endorsement.

The only other major difference is the day you pass your receive your PPL license, assuming you have conducted 3 take offs and landings in the prior 90 days, you will be able to take passengers. An LAPL requires you to complete 10 hours solo once receiving your LAPL license before taking passengers.


Why do some airports not have ICAO codes?

There is plenty of information on the Internet on how certain and specific identifiers came to life, however the codes are sometimes not directly assigned by ICAO, but by the member nations.

  ICAO Document 7910 - Location Identifiers contains codes allocated by national governments, on behalf of ICAO, to airports, airfields and other facilities such as ATC and weather stations.

Ultimately, it is the national CAA's or other authorities' decision whether to assign a code and get it validated through ICAO. The decision may be based on political, historical or other reasons, there is no minimum requirements for airports to receive an ICAO code.

  Am I correct in assuming that airports without ICAO codes don't have codes because of the lack of a control tower? Or is there other reasons for this?

The availability of a control tower is not a requirement for ICAO codes, even small uncontrolled fields with grass strips can have an ICAO code, example: EDKW / Werdohl-Küntrop (600m grass / uncontrolled / PPR)


Where to obtain a list of active NDB approaches?

This list comes from a database query against an ARINC 424 navigation database. The data is available on a subscription basis (for a fee) from the FAA as a raw, computer-readable data file, but it is not human readable, and querying it requires special software not accessible to the typical interested party. I have done the query for you and pasted the results.

Note the database doesn't distinguish between "NDB RWY XX" and "NDB OR GPS RWY XX" so the titles here may not precisely match what you see on the plate.

Time permitting I'll see if I can update the list (and note any changes) using the most up-to-date navigation database. This list is based on an expired (by 2 months or so) database. These approaches are dropping like flies.

02A  NDB RWY 26  (CLANTON, AL)
06FA NDB RWY 09  (JUPITER, FL)
06FA NDB RWY 27  (JUPITER, FL)
0F2  NDB RWY 17  (BOWIE, TX)
0F2  NDB RWY 35  (BOWIE, TX)
0M3  NDB RWY 02  (HOHENWALD, TN)
15F  NDB RWY 18  (HASKELL, TX)
16G  NDB RWY 24  (TIFFIN, OH)
1B1  NDB-A       (HUDSON, NY)
1B9  NDB RWY 32  (MANSFIELD, MA)
1G3  NDB RWY 01  (KENT, OH)
1H8  NDB RWY 04  (CASEY, IL)
1H8  NDB RWY 22  (CASEY, IL)
1J0  NDB-A       (BONIFAY, FL)
1S3  NDB RWY 26  (FORSYTH, MT)
21D  NDB RWY 04  (ST PAUL, MN)
23R  NDB RWY 35  (DEVINE, TX)
28J  NDB RWY 09  (PALATKA, FL)
2A0  NDB RWY 03  (DAYTON, TN)
2B7  NDB RWY 36  (PITTSFIELD, ME)
2F5  NDB RWY 16  (LAMESA, TX)
2F5  NDB RWY 34  (LAMESA, TX)
2G9  NDB RWY 25  (SOMERSET, PA)
2H0  NDB-A       (SHELBYVILLE, IL)
2J5  NDB RWY 17  (MILLEN, GA)
2M2  NDB RWY 17  (LAWRENCEBURG, TN)
2R6  NDB RWY 36  (BUNKIE, LA)
35A  NDB RWY 05  (UNION, SC)
3B4  NDB-B       (ELIOT, ME)
3F3  NDB RWY 18  (MANSFIELD, LA)
3F4  NDB RWY 09  (VIVIAN, LA)
3JC  NDB-B       (JUNCTION CITY, KS)
45R  NDB RWY 13  (KOUNTZE/SILSBEE, TX)
48Y  NDB RWY 33  (PINECREEK, MN)
4A9  NDB-A       (FT PAYNE, AL)
4F2  NDB RWY 35  (CARTHAGE, TX)
4K6  NDB RWY 36  (BLOOMFIELD, IA)
4R7  NDB RWY 16  (EUNICE, LA)
4V8  NDB RWY 01  (WEST DOVER, VT)
53A  NDB RWY 18  (MONTEZUMA, GA)
5R4  NDB RWY 18  (FOLEY, AL)
5R8  NDB RWY 16  (DE QUINCY, LA)
6B6  NDB-A       (STOW, MA)
70J  NDB RWY 13  (CAIRO, GA)
79J  NDB RWY 29  (ANDALUSIA/OPP, AL)
79J  NDB-A       (ANDALUSIA/OPP, AL)
7F3  NDB RWY 35  (CADDO MILLS, TX)
8A0  NDB-A       (ALBERTVILLE, AL)
8B0  NDB-A       (RANGELEY, ME)
8F3  NDB RWY 35  (CROSBYTON, TX)
8G2  NDB RWY 14  (CORRY, PA)
D73  NDB-A       (MONROE, GA)
E30  NDB RWY 35  (BALLINGER, TX)
E38  NDB RWY 19  (ALPINE, TX)
F10  NDB RWY 36  (HENRYETTA, OK)
F17  NDB RWY 17  (CENTER, TX)
F44  NDB RWY 35  (ATHENS, TX)
F46  NDB-A       (ROCKWALL, TX)
F99  NDB RWY 17  (HOLDENVILLE, OK)
I23  NDB RWY 23  (WASHINGTON COURT HOUSE, OH)
I68  NDB-A       (LEBANON, OH)
I69  NDB RWY 22  (BATAVIA, OH)
K34  NDB-D       (GARDNER, KS)
K88  NDB RWY 01  (IOLA, KS)
KAAA NDB RWY 21  (LINCOLN, IL)
KAAF NDB RWY 14  (APALACHICOLA, FL)
KAAF NDB RWY 32  (APALACHICOLA, FL)
KAAS NDB RWY 23  (CAMPBELLSVILLE, KY)
KABI NDB RWY 35R (ABILENE, TX)
KABR NDB RWY 31  (ABERDEEN, SD)
KABY NDB RWY 04  (ALBANY, GA)
KACK NDB RWY 24  (NANTUCKET, MA)
KACP NDB RWY 36  (OAKDALE, LA)
KADF NDB RWY 04  (ARKADELPHIA, AR)
KADG NDB RWY 05  (ADRIAN, MI)
KAFK NDB RWY 15  (NEBRASKA CITY, NE)
KAFK NDB RWY 33  (NEBRASKA CITY, NE)
KAHN NDB RWY 27  (ATHENS, GA)
KAHQ NDB RWY 20  (WAHOO, NE)
KAID NDB RWY 30  (ANDERSON, IN)
KAIK NDB RWY 25  (AIKEN, SC)
KAIT NDB RWY 16  (AITKIN, MN)
KAJR NDB RWY 06  (CORNELIA, GA)
KAKH NDB RWY 03  (GASTONIA, NC)
KAKQ NDB RWY 20  (WAKEFIELD, VA)
KAKR NDB RWY 25  (AKRON, OH)
KALN NDB RWY 17  (ALTON-ST LOUIS, IL)
KALW NDB RWY 20  (WALLA WALLA, WA)
KALX NDB-A       (ALEXANDER CITY, AL)
KAMA NDB RWY 04  (AMARILLO, TX)
KAMT NDB RWY 23  (WEST UNION, OH)
KANB NDB RWY 05  (ANNISTON, AL)
KANQ NDB RWY 05  (ANGOLA, IN)
KAPG NDB RWY 22  (ABERDEEN PROVING GROUNDS, MD)
KAPN NDB RWY 01  (ALPENA, MI)
KAPT NDB RWY 04  (JASPER, TN)
KAQP NDB RWY 13  (APPLETON, MN)
KARM NDB RWY 14  (WHARTON, TX)
KARM NDB RWY 32  (WHARTON, TX)
KARV NDB RWY 28  (MINOCQUA-WOODRUFF, WI)
KASH NDB RWY 14  (NASHUA, NH)
KATA NDB RWY 05  (ATLANTA, TX)
KATS NDB RWY 12  (ARTESIA, NM)
KATS NDB RWY 30  (ARTESIA, NM)
KATY NDB RWY 35  (WATERTOWN, SD)
KAVQ NDB RWY 12  (MARANA, AZ)
KAWG NDB RWY 31  (WASHINGTON, IA)
KAWO NDB RWY 34  (ARLINGTON, WA)
KAXA NDB RWY 12  (ALGONA, IA)
KAZC NDB-A       (COLORADO CITY, AZ)
KAZE NDB RWY 14  (HAZLEHURST, GA)
KAZO NDB RWY 35  (KALAMAZOO, MI)
KBBB NDB RWY 14  (BENSON, MN)
KBBD NDB RWY 17  (BRADY, TX)
KBBP NDB RWY 07  (BENNETTSVILLE, SC)
KBCB NDB-A       (BLACKSBURG, VA)
KBED NDB RWY 29  (BEDFORD, MA)
KBEH NDB RWY 28  (BENTON HARBOR, MI)
KBFK NDB-A       (BUFFALO, OK)
KBFW NDB RWY 25  (SILVER BAY, MN)
KBGF NDB RWY 18  (WINCHESTER, TN)
KBHC NDB RWY 08  (BAXLEY, GA)
KBHK NDB RWY 13  (BAKER, MT)
KBHK NDB RWY 31  (BAKER, MT)
KBIL NDB RWY 10L (BILLINGS, MT)
KBKS NDB RWY 35  (FALFURRIAS, TX)
KBKT NDB-A       (BLACKSTONE, VA)
KBMC NDB-A       (BRIGHAM CITY, UT)
KBOI NDB RWY 10R (BOISE, ID)
KBPP NDB RWY 29  (BOWMAN, ND)
KBQP NDB RWY 34  (BASTROP, LA)
KBRD NDB RWY 23  (BRAINERD, MN)
KBST NDB RWY 15  (BELFAST, ME)
KBTL NDB RWY 23R (BATTLE CREEK, MI)
KBTR NDB RWY 31  (BATON ROUGE, LA)
KBUB NDB RWY 15  (BURWELL, NE)
KBVS NDB RWY 11  (BURLINGTON/MT VERNON, WA)
KBWG NDB RWY 03  (BOWLING GREEN, KY)
KCAV NDB RWY 14  (CLARION, IA)
KCBG NDB RWY 34  (CAMBRIDGE, MN)
KCBK NDB RWY 17  (COLBY, KS)
KCCY NDB RWY 12  (CHARLES CITY, IA)
KCDA NDB RWY 02  (LYNDONVILLE, VT)
KCDR NDB RWY 20  (CHADRON, NE)
KCEU NDB RWY 25  (CLEMSON, SC)
KCFJ NDB RWY 04  (CRAWFORDSVILLE, IN)
KCFV NDB RWY 35  (COFFEYVILLE, KS)
KCGE NDB RWY 34  (CAMBRIDGE, MD)
KCHD NDB RWY 04R (CHANDLER, AZ)
KCHQ NDB RWY 36  (CHARLESTON, MO)
KCII NDB RWY 23  (CHOTEAU, MT)
KCIR NDB RWY 14  (CAIRO, IL)
KCIU NDB RWY 34  (SAULT STE MARIE, MI)
KCJR NDB RWY 04  (CULPEPER, VA)
KCKC NDB RWY 27  (GRAND MARAIS, MN)
KCKF NDB RWY 10  (CORDELE, GA)
KCKI NDB RWY 14  (KINGSTREE, SC)
KCKN NDB RWY 13  (CROOKSTON, MN)
KCMI NDB RWY 32R (CHAMPAIGN-URBANA, IL)
KCMY NDB RWY 29  (SPARTA, WI)
KCNH NDB-A       (CLAREMONT, NH)
KCNI NDB RWY 05  (CANTON, GA)
KCNK NDB-A       (CONCORDIA, KS)
KCNP NDB RWY 30  (CHAPPELL, NE)
KCNW NDB RWY 35R (WACO, TX)
KCOE NDB RWY 06  (COEUR D'ALENE, ID)
KCOQ NDB RWY 17  (CLOQUET, MN)
KCOQ NDB RWY 35  (CLOQUET, MN)
KCOS NDB RWY 35L (COLORADO SPRINGS, CO)
KCPC NDB RWY 06  (WHITEVILLE, NC)
KCQB NDB RWY 35  (CHANDLER, OK)
KCQX NDB-A       (CHATHAM, MA)
KCRS NDB RWY 14  (CORSICANA, TX)
KCRS NDB RWY 32  (CORSICANA, TX)
KCSB NDB RWY 14  (CAMBRIDGE, NE)
KCSB NDB RWY 32  (CAMBRIDGE, NE)
KCSQ NDB RWY 34  (CRESTON, IA)
KCUH NDB RWY 36  (CUSHING, OK)
KCVC NDB RWY 28  (ATLANTA, GA)
KCVO NDB RWY 17  (CORVALLIS, OR)
KCVX NDB RWY 09  (CHARLEVOIX, MI)
KCVX NDB RWY 27  (CHARLEVOIX, MI)
KCWC NDB RWY 35  (WICHITA FALLS, TX)
KCWS NDB-A       (CONWAY, AR)
KCWV NDB RWY 09  (CLAXTON, GA)
KCXO NDB RWY 14  (HOUSTON, TX)
KCXU NDB RWY 08  (CAMILLA, GA)
KCYS NDB RWY 27  (CHEYENNE, WY)
KCYW NDB RWY 35  (CLAY CENTER, KS)
KCZT NDB RWY 31  (CARRIZO SPRINGS, TX)
KDAA NDB RWY 32  (FT BELVOIR, VA)
KDAW NDB RWY 33  (ROCHESTER, NH)
KDAW NDB-B       (ROCHESTER, NH)
KDAY NDB RWY 06R (DAYTON, OH)
KDCM NDB RWY 35  (CHESTER, SC)
KDET NDB RWY 15  (DETROIT, MI)
KDEW NDB-A       (DEER PARK, WA)
KDLC NDB RWY 07  (DILLON, SC)
KDLZ NDB RWY 10  (DELAWARE, OH)
KDMO NDB RWY 18  (SEDALIA, MO)
KDMO NDB RWY 36  (SEDALIA, MO)
KDNL NDB RWY 11  (AUGUSTA, GA)
KDNL NDB RWY DMC (AUGUSTA, GA)
KDNS NDB RWY 30  (DENISON, IA)
KDRI NDB RWY 36  (DE RIDDER, LA)
KDRT NDB RWY 13  (DEL RIO, TX)
KDTO NDB RWY 18  (DENTON, TX)
KDVK NDB-A       (DANVILLE, KY)
KDXX NDB RWY 32  (MADISON, MN)
KDYB NDB RWY 06  (SUMMERVILLE, SC)
KEAR NDB RWY 36  (KEARNEY, NE)
KEAU NDB RWY 22  (EAU CLAIRE, WI)
KEBS NDB RWY 32  (WEBSTER CITY, IA)
KECG NDB RWY 10  (ELIZABETH CITY, NC)
KEFW NDB RWY 32  (JEFFERSON, IA)
KEGQ NDB RWY 13  (EMMETSBURG, IA)
KEGQ NDB RWY 31  (EMMETSBURG, IA)
KEGT NDB RWY 35  (WELLINGTON, KS)
KEHA NDB RWY 35  (ELKHART, KS)
KEHO NDB RWY 23  (SHELBY, NC)
KEMT NDB-C       (EL MONTE, CA)
KEOE NDB RWY 22  (NEWBERRY, SC)
KEOK NDB RWY 14  (KEOKUK, IA)
KEOK NDB RWY 26  (KEOKUK, IA)
KEOP NDB RWY 25  (WAVERLY, OH)
KEPM NDB RWY 15  (EASTPORT, ME)
KEPM NDB RWY 33  (EASTPORT, ME)
KERI NDB RWY 06  (ERIE, PA)
KERI NDB RWY 24  (ERIE, PA)
KERV NDB RWY 30  (KERRVILLE, TX)
KETC NDB RWY 27  (TARBORO, NC)
KETN NDB RWY 35  (EASTLAND, TX)
KEUL NDB RWY 30  (CALDWELL, ID)
KEVB NDB RWY 29  (NEW SMYRNA BEACH, FL)
KEVV NDB RWY 22  (EVANSVILLE, IN)
KEVY NDB-A       (MIDDLETOWN, DE)
KEWB NDB RWY 05  (NEW BEDFORD, MA)
KEWK NDB RWY 35  (NEWTON, KS)
KEYE NDB RWY 21  (INDIANAPOLIS, IN)
KEYW NDB-A       (KEY WEST, FL)
KEZF NDB RWY 24  (FREDERICKSBURG, VA)
KEZM NDB RWY 02  (EASTMAN, GA)
KEZZ NDB RWY 35  (CAMERON, MO)
KFAF NDB RWY 14  (FT EUSTIS, VA)
KFBG NDB RWY 27  (FT BRAGG, NC)
KFBY NDB-A       (FAIRBURY, NE)
KFCH NDB-B       (FRESNO, CA)
KFDW NDB RWY 04  (WINNSBORO, SC)
KFES NDB RWY 36  (FESTUS, MO)
KFFC NDB RWY 31  (ATLANTA, GA)
KFFL NDB RWY 36  (FAIRFIELD, IA)
KFFM NDB RWY 31  (FERGUS FALLS, MN)
KFHR NDB RWY 34  (FRIDAY HARBOR, WA)
KFHU NDB RWY 26  (FT HUACHUCA, AZ)
KFIT NDB RWY 20  (FITCHBURG, MA)
KFIT NDB-A       (FITCHBURG, MA)
KFKR NDB RWY 09  (FRANKFORT, IN)
KFLV NDB RWY 34  (FT LEAVENWORTH, KS)
KFMH NDB RWY 23  (FALMOUTH, MA)
KFMZ NDB RWY 17  (FAIRMONT, NE)
KFMZ NDB RWY 35  (FAIRMONT, NE)
KFNB NDB-A       (FALLS CITY, NE)
KFOE NDB RWY 13  (TOPEKA, KS)
KFOZ NDB RWY 15  (BIGFORK, MN)
KFPR NDB RWY 28L (FT PIERCE, FL)
KFPR NDB-A       (FT PIERCE, FL)
KFRG NDB RWY 01  (FARMINGDALE, NY)
KFRI NDB RWY 04  (FT RILEY, KS)
KFSE NDB RWY 34  (FOSSTON, MN)
KFSI NDB RWY 17  (FT SILL, OK)
KFSI NDB-A       (FT SILL, OK)
KFSK NDB RWY 18  (FT SCOTT, KS)
KFSM NDB RWY 25  (FT SMITH, AR)
KFTG NDB RWY 26  (DENVER, CO)
KFTK NDB RWY 18  (FT KNOX, KY)
KFTY NDB RWY 08  (ATLANTA, GA)
KFVX NDB RWY 03  (FARMVILLE, VA)
KFWC NDB RWY 09  (FAIRFIELD, IL)
KFXY NDB RWY 33  (FOREST CITY, IA)
KFYE NDB RWY 19  (SOMERVILLE, TN)
KFYM NDB RWY 20  (FAYETTEVILLE, TN)
KFZG NDB RWY 01  (FITZGERALD, GA)
KFZI NDB RWY 27  (FOSTORIA, OH)
KGAI NDB RWY 14  (GAITHERSBURG, MD)
KGBD NDB RWY 35  (GREAT BEND, KS)
KGBR NDB-A       (GREAT BARRINGTON, MA)
KGCK NDB RWY 35  (GARDEN CITY, KS)
KGCY NDB RWY 05  (GREENEVILLE, TN)
KGDV NDB RWY 12  (GLENDIVE, MT)
KGEY NDB RWY 34  (GREYBULL, WY)
KGGE NDB RWY 05  (GEORGETOWN, SC)
KGGF NDB RWY 15  (GRANT, NE)
KGGF NDB RWY 33  (GRANT, NE)
KGGG NDB RWY 13  (LONGVIEW, TX)
KGGW NDB RWY 30  (GLASGOW, MT)
KGHG NDB RWY 06  (MARSHFIELD, MA)
KGHG NDB RWY 24  (MARSHFIELD, MA)
KGLR NDB RWY 09  (GAYLORD, MI)
KGLY NDB RWY 04  (CLINTON, MO)
KGLY NDB RWY 22  (CLINTON, MO)
KGMU NDB RWY 01  (GREENVILLE, SC)
KGNC NDB RWY 35  (SEMINOLE, TX)
KGNF NDB RWY 13  (GRENADA, MS)
KGNG NDB RWY 25  (GOODING, ID)
KGOV NDB RWY 14  (GRAYLING, MI)
KGRD NDB RWY 27  (GREENWOOD, SC)
KGRF NDB RWY 15  (FT LEWIS, WA)
KGRF NDB RWY 33  (FT LEWIS, WA)
KGRK NDB RWY 15  (FT HOOD, TX)
KGRN NDB RWY 22  (GORDON, NE)
KGSO NDB RWY 14  (GREENSBORO, NC)
KGTB NDB RWY 15  (FT DRUM, NY)
KGTB NDB RWY 33  (FT DRUM, NY)
KGTF NDB RWY 34  (GREAT FALLS, MT)
KGUR NDB RWY 32  (GUERNSEY, WY)
KGUY NDB RWY 18  (GUYMON, OK)
KGVL NDB RWY 05  (GAINESVILLE, GA)
KGWR NDB RWY 34  (GWINNER, ND)
KGXY NDB RWY 34  (GREELEY, CO)
KGYH NDB RWY 05  (GREENVILLE, SC)
KGYI NDB RWY 17L (SHERMAN-DENISON, TX)
KGYL NDB RWY 31  (GLENCOE, MN)
KGYY NDB RWY 30  (GARY, IN)
KHBV NDB RWY 13  (HEBBRONVILLE, TX)
KHDO NDB RWY 35R (HONDO, TX)
KHEG NDB-A       (JACKSONVILLE, FL)
KHFF NDB RWY 11  (CAMP MACKALL, NC)
KHFY NDB RWY 01  (INDIANAPOLIS, IN)
KHHG NDB RWY 09  (HUNTINGTON, IN)
KHHW NDB RWY 35  (HUGO, OK)
KHIO NDB-B       (PORTLAND, OR)
KHJH NDB RWY 12  (HEBRON, NE)
KHLN NDB-D       (HELENA, MT)
KHMY NDB RWY 17  (LEXINGTON, OK)
KHMY NDB RWY 35  (LEXINGTON, OK)
KHNZ NDB RWY 06  (OXFORD-HENDERSON, NC)
KHOC NDB RWY 23  (HILLSBORO, OH)
KHOE NDB RWY 14  (HOMERVILLE, GA)
KHOP NDB RWY 23  (FT CAMPBELL/HOPKINSVILLE, KY)
KHQG NDB RWY 02  (HUGOTON, KS)
KHQU NDB RWY 10  (THOMSON, GA)
KHRJ NDB RWY 23  (ERWIN, NC)
KHRO NDB RWY 18  (HARRISON, AR)
KHRU NDB RWY 17  (HERINGTON, KS)
KHRU NDB RWY 35  (HERINGTON, KS)
KHRX NDB RWY 20  (HEREFORD, TX)
KHSA NDB RWY 18  (BAY ST LOUIS, MS)
KHUA NDB RWY 17  (REDSTONE ARSENAL, AL)
KHUT NDB RWY 13  (HUTCHINSON, KS)
KHVC NDB RWY 26  (HOPKINSVILLE, KY)
KHVS NDB RWY 03  (HARTSVILLE, SC)
KHVS NDB RWY 21  (HARTSVILLE, SC)
KHYI NDB RWY 13  (SAN MARCOS, TX)
KHYW NDB RWY 04  (CONWAY, SC)
KHYW NDB RWY 22  (CONWAY, SC)
KHZD NDB RWY 01  (HUNTINGDON, TN)
KHZR NDB RWY 36  (NEW ROADS, LA)
KIAG NDB RWY 28R (NIAGARA FALLS, NY)
KICL NDB-A       (CLARINDA, IA)
KICT NDB RWY 01R (WICHITA, KS)
KIDA NDB RWY 20  (IDAHO FALLS, ID)
KIDP NDB RWY 35  (INDEPENDENCE, KS)
KIER NDB RWY 35  (NATCHITOCHES, LA)
KIIB NDB RWY 18  (INDEPENDENCE, IA)
KIKG NDB RWY 13  (KINGSVILLE, TX)
KILN NDB RWY 04L (WILMINGTON, OH)
KILN NDB RWY 22R (WILMINGTON, OH)
KIMT NDB RWY 01  (IRON MT-KINGSFORD, MI)
KINL NDB RWY 31  (INTERNATIONAL FALLS, MN)
KIOB NDB RWY 03  (MT STERLING, KY)
KIOB NDB RWY 21  (MT STERLING, KY)
KIPJ NDB RWY 23  (LINCOLNTON, NC)
KIRS NDB RWY 18  (STURGIS, MI)
KIRS NDB RWY 24  (STURGIS, MI)
KISB NDB RWY 17  (SIBLEY, IA)
KISB NDB RWY 35  (SIBLEY, IA)
KISN NDB RWY 29  (WILLISTON, ND)
KISW NDB RWY 02  (WISCONSIN RAPIDS, WI)
KISW NDB RWY 30  (WISCONSIN RAPIDS, WI)
KITR NDB RWY 15  (BURLINGTON, CO)
KIZG NDB-B       (FRYEBURG, ME)
KJES NDB RWY 11  (JESUP, GA)
KJES NDB RWY 29  (JESUP, GA)
KJMR NDB RWY 35  (MORA, MN)
KJMS NDB RWY 31  (JAMESTOWN, ND)
KJNX NDB RWY 03  (SMITHFIELD, NC)
KJSV NDB-A       (SALLISAW, OK)
KJVW NDB RWY 12  (RAYMOND, MS)
KJVY NDB RWY 18  (JEFFERSONVILLE, IN)
KJXN NDB RWY 24  (JACKSON, MI)
KJYG NDB RWY 33  (ST JAMES, MN)
KJYL NDB RWY 23  (SYLVANIA, GA)
KJYR NDB RWY 17  (YORK, NE)
KJYR NDB RWY 35  (YORK, NE)
KKLS NDB-A       (KELSO, WA)
KLCG NDB RWY 18  (WAYNE, NE)
KLCG NDB RWY 23  (WAYNE, NE)
KLCG NDB RWY 36  (WAYNE, NE)
KLCI NDB RWY 08  (LACONIA, NH)
KLCK NDB RWY 05R (COLUMBUS, OH)
KLCK NDB RWY 23L (COLUMBUS, OH)
KLCQ NDB RWY 28  (LAKE CITY, FL)
KLDM NDB RWY 26  (LUDINGTON, MI)
KLEE NDB RWY 31  (LEESBURG, FL)
KLGD NDB-B       (LA GRANDE, OR)
KLHW NDB RWY 33R (FT STEWART, GA)
KLIU NDB RWY 01  (LITTLEFIELD, TX)
KLKR NDB RWY 24  (LANCASTER, SC)
KLLN NDB RWY 17  (LEVELLAND, TX)
KLLN NDB RWY 35  (LEVELLAND, TX)
KLNN NDB RWY 10  (WILLOUGHBY, OH)
KLOU NDB RWY 33  (LOUISVILLE, KY)
KLQK NDB RWY 05  (PICKENS, SC)
KLQR NDB RWY 17  (LARNED, KS)
KLRD NDB RWY 17L (LAREDO, TX)
KLRF NDB RWY 25  (JACKSONVILLE, AR)
KLSE NDB RWY 18  (LA CROSSE, WI)
KLUA NDB-A       (LURAY, VA)
KLUK NDB RWY 21L (CINCINNATI, OH)
KLUK NDB RWY 25  (CINCINNATI, OH)
KLUL NDB RWY 13  (LAUREL, MS)
KLWM NDB RWY 05  (LAWRENCE, MA)
KLXL NDB RWY 31  (LITTLE FALLS, MN)
KLXY NDB-A       (MEXIA, TX)
KLYO NDB RWY 17R (LYONS, KS)
KLZU NDB RWY 25  (LAWRENCEVILLE, GA)
KMAI NDB-C       (MARIANNA, FL)
KMAN NDB-A       (NAMPA, ID)
KMAO NDB RWY 04  (MARION, SC)
KMBT NDB RWY 18  (MURFREESBORO, TN)
KMDH NDB RWY 18L (CARBONDALE-MURPHYSBORO, IL)
KMDZ NDB RWY 34  (MEDFORD, WI)
KMEY NDB RWY 20  (MAPLETON, IA)
KMEZ NDB RWY 27  (MENA, AR)
KMFD NDB RWY 32  (MANSFIELD, OH)
KMFI NDB RWY 05  (MARSHFIELD, WI)
KMFI NDB RWY 16  (MARSHFIELD, WI)
KMGM NDB RWY 10  (MONTGOMERY, AL)
KMGR NDB-A       (MOULTRIE, GA)
KMGY NDB-A       (DAYTON, OH)
KMHL NDB RWY 36  (MARSHALL, MO)
KMIV NDB RWY 14  (MILLVILLE, NJ)
KMKC NDB RWY 19  (KANSAS CITY, MO)
KMKV NDB RWY 04  (MARKSVILLE, LA)
KMLE NDB RWY 12  (OMAHA, NE)
KMLJ NDB RWY 28  (MILLEDGEVILLE, GA)
KMMI NDB RWY 02  (ATHENS, TN)
KMMI NDB RWY 20  (ATHENS, TN)
KMNI NDB RWY 02  (MANNING, SC)
KMNM NDB RWY 03  (MENOMINEE, MI)
KMNZ NDB RWY 36  (HAMILTON, TX)
KMOB NDB RWY 14  (MOBILE, AL)
KMOR NDB RWY 05  (MORRISTOWN, TN)
KMPZ NDB RWY 33  (MT PLEASANT, IA)
KMQI NDB RWY 05  (MANTEO, NC)
KMQI NDB RWY 17  (MANTEO, NC)
KMQW NDB RWY 21  (MC RAE, GA)
KMQY NDB RWY 32  (SMYRNA, TN)
KMRH NDB RWY 14  (BEAUFORT, NC)
KMRH NDB RWY 21  (BEAUFORT, NC)
KMRJ NDB RWY 22  (MINERAL POINT, WI)
KMSV NDB RWY 15  (MONTICELLO, NY)
KMTH NDB-A       (MARATHON, FL)
KMTO NDB RWY 29  (MATTOON-CHARLESTON, IL)
KMUI NDB-A       (FT INDIANTOWN GAP, PA)
KMWA NDB RWY 20  (MARION, IL)
KMWH NDB RWY 32R (MOSES LAKE, WA)
KMWO NDB RWY 23  (MIDDLETOWN, OH)
KMWO NDB-A       (MIDDLETOWN, OH)
KMZH NDB RWY 04  (MOOSE LAKE, MN)
KNEL NDB RWY 24  (LAKEHURST, NJ)
KNRN NDB RWY 16  (NORTON, KS)
KNRN NDB RWY 34  (NORTON, KS)
KOAJ NDB RWY 05  (JACKSONVILLE, NC)
KOCH NDB RWY 18  (NACOGDOCHES, TX)
KODO NDB RWY 20  (ODESSA, TX)
KODX NDB RWY 13  (ORD, NE)
KOEL NDB RWY 34  (OAKLEY, KS)
KOIN NDB RWY 35  (OBERLIN, KS)
KOJC NDB-B       (OLATHE, KS)
KOKS NDB RWY 12  (OSHKOSH, NE)
KOKZ NDB RWY 13  (SANDERSVILLE, GA)
KOLD NDB RWY 22  (OLD TOWN, ME)
KOLF NDB RWY 29  (WOLF POINT, MT)
KOLS NDB-C       (NOGALES, AZ)
KOLY NDB RWY 03  (OLNEY-NOBLE, IL)
KONA NDB RWY 30  (WINONA, MN)
KONO NDB RWY 32  (ONTARIO, OR)
KONZ NDB RWY 04  (DETROIT/GROSSE ILE, MI)
KOOA NDB RWY 22  (OSKALOOSA, IA)
KOPL NDB RWY 18  (OPELOUSAS, LA)
KOPN NDB RWY 30  (THOMASTON, GA)
KORB NDB RWY 13  (ORR, MN)
KORC NDB RWY 34  (ORANGE CITY, IA)
KORE NDB RWY 01  (ORANGE, MA)
KORE NDB RWY 32  (ORANGE, MA)
KOSH NDB RWY 36  (OSHKOSH, WI)
KOSU NDB RWY 09R (COLUMBUS, OH)
KOTG NDB RWY 29  (WORTHINGTON, MN)
KOTH NDB RWY 04  (NORTH BEND, OR)
KOUN NDB RWY 03  (NORMAN, OK)
KOUN NDB RWY 35  (NORMAN, OK)
KOWP NDB RWY 35  (SAND SPRINGS, OK)
KOXD NDB RWY 05  (OXFORD, OH)
KPCW NDB RWY 27  (PORT CLINTON, OH)
KPCZ NDB RWY 31  (WAUPACA, WI)
KPEA NDB RWY 34  (PELLA, IA)
KPEO NDB RWY 28  (PENN YAN, NY)
KPHF NDB RWY 02  (NEWPORT NEWS, VA)
KPHF NDB RWY 20  (NEWPORT NEWS, VA)
KPHG NDB-A       (PHILLIPSBURG, KS)
KPHH NDB RWY 36  (ANDREWS, SC)
KPHN NDB RWY 04  (PORT HURON, MI)
KPHT NDB RWY 02  (PARIS, TN)
KPIA NDB RWY 31  (PEORIA, IL)
KPIM NDB RWY 09  (PINE MOUNTAIN, GA)
KPKF NDB RWY 36  (PARK FALLS, WI)
KPMV NDB RWY 16  (PLATTSMOUTH, NE)
KPMV NDB RWY 34  (PLATTSMOUTH, NE)
KPNA NDB-A       (PINEDALE, WY)
KPNM NDB RWY 15  (PRINCETON, MN)
KPNS NDB RWY 35  (PENSACOLA, FL)
KPOB NDB RWY 23  (FAYETTEVILLE, NC)
KPOE NDB RWY 16  (FT POLK, LA)
KPOE NDB RWY 34  (FT POLK, LA)
KPOH NDB RWY 12  (POCAHONTAS, IA)
KPOY NDB RWY 31  (POWELL, WY)
KPPA NDB RWY 17  (PAMPA, TX)
KPSN NDB RWY 36  (PALESTINE, TX)
KPTD NDB RWY 24  (POTSDAM, NY)
KPTN NDB RWY 06  (PATTERSON, LA)
KPTT NDB RWY 17  (PRATT, KS)
KPVC NDB RWY 25  (PROVINCETOWN, MA)
KPVJ NDB RWY 35  (PAULS VALLEY, OK)
KPWC NDB RWY 34  (PINE RIVER, MN)
KPWT NDB RWY 02  (BREMERTON, WA)
KPYG NDB RWY 23  (PAGELAND, SC)
KPYX NDB-A       (PERRYTON, TX)
KRBE NDB RWY 31  (BASSETT, NE)
KRCX NDB RWY 32  (LADYSMITH, WI)
KRFD NDB RWY 01  (CHICAGO/ROCKFORD, IL)
KRFI NDB-B       (HENDERSON, TX)
KRKD NDB RWY 03  (ROCKLAND, ME)
KRKD NDB RWY 31  (ROCKLAND, ME)
KRNT NDB RWY 16  (RENTON, WA)
KROG NDB RWY 20  (ROGERS, AR)
KROS NDB RWY 34  (RUSH CITY, MN)
KRRT NDB RWY 31  (WARROAD, MN)
KRSN NDB RWY 18  (RUSTON, LA)
KRSN NDB RWY 36  (RUSTON, LA)
KRSV NDB RWY 17  (ROBINSON, IL)
KRUE NDB-A       (RUSSELLVILLE, AR)
KRUQ NDB RWY 20  (SALISBURY, NC)
KRVJ NDB RWY 11  (REIDSVILLE, GA)
KRVN NDB RWY 07  (ROGERSVILLE, TN)
KRYM NDB RWY 31  (CAMP RIPLEY, MN)
KRYV NDB RWY 05  (WATERTOWN, WI)
KRYV NDB RWY 23  (WATERTOWN, WI)
KSAA NDB-A       (SARATOGA, WY)
KSAW NDB RWY 01  (MARQUETTE, MI)
KSAZ NDB RWY 14  (STAPLES, MN)
KSBD NDB RWY 06  (SAN BERNARDINO, CA)
KSBO NDB RWY 14  (SWAINSBORO, GA)
KSBU NDB RWY 34  (BLUE EARTH, MN)
KSBX NDB RWY 23  (SHELBY, MT)
KSCH NDB RWY 22  (SCHENECTADY, NY)
KSDA NDB RWY 04  (SHENANDOAH, IA)
KSDY NDB RWY 01  (SIDNEY, MT)
KSDY NDB RWY 19  (SIDNEY, MT)
KSEM NDB RWY 33  (SELMA, AL)
KSER NDB RWY 05  (SEYMOUR, IN)
KSFB NDB-B       (ORLANDO, FL)
KSFB NDB-C       (ORLANDO, FL)
KSGH NDB RWY 24  (SPRINGFIELD, OH)
KSGS NDB-B       (SOUTH ST PAUL, MN)
KSGT NDB RWY 18  (STUTTGART, AR)
KSHD NDB RWY 05  (STAUNTON/WAYNESBORO/HARR, VA)
KSHL NDB RWY 33  (SHELDON, IA)
KSHN NDB-A       (SHELTON, WA)
KSIF NDB RWY 31  (REIDSVILLE, NC)
KSIV NDB RWY 36  (SULLIVAN, IN)
KSIY NDB-A       (MONTAGUE, CA)
KSJT NDB RWY 03  (SAN ANGELO, TX)
KSJX NDB RWY 27  (BEAVER I, MI)
KSKI NDB RWY 36  (SAC CITY, IA)
KSLB NDB RWY 17  (STORM LAKE, IA)
KSLB NDB RWY 35  (STORM LAKE, IA)
KSLI NDB RWY 22L (LOS ALAMITOS, CA)
KSLN NDB RWY 35  (SALINA, KS)
KSLO NDB RWY 18  (SALEM, IL)
KSMS NDB RWY 23  (SUMTER, SC)
KSNK NDB RWY 35  (SNYDER, TX)
KSOA NDB RWY 18  (SONORA, TX)
KSOW NDB-A       (SHOW LOW, AZ)
KSOY NDB RWY 18  (SIOUX CENTER, IA)
KSPF NDB-A       (SPEARFISH, SD)
KSPS NDB RWY 33L (WICHITA FALLS, TX)
KSPW NDB RWY 30  (SPENCER, IA)
KSQI NDB RWY 07  (STERLING/ROCKFALLS, IL)
KSRB NDB RWY 04  (SPARTA, TN)
KSRE NDB RWY 16  (SEMINOLE, OK)
KSTK NDB RWY 33  (STERLING, CO)
KSTP NDB RWY 31  (ST PAUL, MN)
KSUN NDB RWY DMA (HAILEY, ID)
KSUS NDB RWY 08R (ST LOUIS, MO)
KSUS NDB RWY 26L (ST LOUIS, MO)
KSUX NDB RWY 13  (SIOUX CITY, IA)
KSUX NDB RWY 17  (SIOUX CITY, IA)
KSUX NDB RWY 31  (SIOUX CITY, IA)
KSUX NDB RWY 35  (SIOUX CITY, IA)
KSVN NDB RWY 28  (SAVANNAH, GA)
KSWO NDB RWY 17  (STILLWATER, OK)
KSWT NDB RWY 16  (SEWARD, NE)
KSWT NDB RWY 34  (SEWARD, NE)
KSWW NDB RWY 17  (SWEETWATER, TX)
KSYF NDB RWY 32  (ST FRANCIS, KS)
KTAD NDB-A       (TRINIDAD, CO)
KTAN NDB RWY 30  (TAUNTON, MA)
KTBN NDB RWY 32  (FT LEONARD WOOD, MO)
KTDW NDB-A       (AMARILLO, TX)
KTHA NDB RWY 18  (TULLAHOMA, TN)
KTIW NDB RWY 35  (TACOMA, WA)
KTNT NDB RWY 09  (MIAMI, FL)
KTOI NDB RWY 07  (TROY, AL)
KTOR NDB RWY 10  (TORRINGTON, WY)
KTOR NDB RWY 28  (TORRINGTON, WY)
KTPF NDB RWY 04  (TAMPA, FL)
KTQH NDB RWY 17  (TAHLEQUAH, OK)
KTQK NDB RWY 35  (SCOTT CITY, KS)
KTRL NDB RWY 17  (TERRELL, TX)
KTRX NDB RWY 18  (TRENTON, MO)
KTRX NDB RWY 36  (TRENTON, MO)
KTTD NDB-A       (PORTLAND, OR)
KTTN NDB RWY 06  (TRENTON, NJ)
KTUP NDB RWY 36  (TUPELO, MS)
KTVC NDB RWY 28  (TRAVERSE CITY, MI)
KTVF NDB RWY 31  (THIEF RIVER FALLS, MN)
KTVI NDB RWY 22  (THOMASVILLE, GA)
KTWF NDB RWY 26  (TWIN FALLS, ID)
KTZR NDB RWY 04  (COLUMBUS, OH)
KUCP NDB RWY 23  (NEW CASTLE, PA)
KUDG NDB RWY 23  (DARLINGTON, SC)
KUIN NDB RWY 04  (QUINCY, IL)
KUKL NDB RWY 36  (BURLINGTON, KS)
KULS NDB RWY 12  (ULYSSES, KS)
KUMP NDB RWY 15  (INDIANAPOLIS, IN)
KUNI NDB RWY 25  (ATHENS/ALBANY, OH)
KUNU NDB RWY 02  (JUNEAU, WI)
KUNU NDB RWY 20  (JUNEAU, WI)
KUTS NDB RWY 18  (HUNTSVILLE, TX)
KUUV NDB RWY 24  (SULLIVAN, MO)
KUVA NDB RWY 33  (UVALDE, TX)
KUWL NDB RWY 09  (NEW CASTLE, IN)
KUWL NDB RWY 27  (NEW CASTLE, IN)
KVHN NDB RWY 21  (VAN HORN, TX)
KVIQ NDB RWY 28  (NEILLSVILLE, WI)
KVNC NDB RWY 31  (VENICE, FL)
KVNW NDB RWY 09  (VAN WERT, OH)
KVTA NDB RWY 09  (NEWARK, OH)
KVTN NDB RWY 32  (VALENTINE, NE)
KVUJ NDB RWY 22L (ALBEMARLE, NC)
KVVV NDB RWY 34  (ORTONVILLE, MN)
KWDR NDB RWY 31  (WINDER, GA)
KWJF NDB-C       (LANCASTER, CA)
KWYS NDB RWY 01  (WEST YELLOWSTONE, MT)
KXVG NDB RWY 31  (LONGVILLE, MN)
KYKM NDB RWY 27  (YAKIMA, WA)
KYKN NDB RWY 31  (YANKTON, SD)
KYNG NDB RWY 32  (YOUNGSTOWN-WARREN, OH)
KZEF NDB RWY 25  (ELKIN, NC)
KZPH NDB RWY 18  (ZEPHYRHILLS, FL)
KZPH NDB RWY 22  (ZEPHYRHILLS, FL)
KZPH NDB RWY 36  (ZEPHYRHILLS, FL)
L39  NDB RWY 36  (LEESVILLE, LA)
L67  NDB-A       (RIALTO, CA)
M02  NDB RWY 17  (DICKSON, TN)
M18  NDB RWY 16  (HOPE, AR)
MYSM NDB RWY 10  (SAN SALVADOR, , BHS)
N94  NDB-B       (CARLISLE, PA)
NY0  NDB RWY 10  (JOHNSTOWN, NY)
NY0  NDB RWY 28  (JOHNSTOWN, NY)
S01  NDB RWY 24  (CONRAD, MT)
S39  NDB RWY 10  (PRINEVILLE, OR)
T41  NDB RWY 30  (LA PORTE, TX)
T85  NDB RWY 31  (YOAKUM, TX)
TX25 NDB RWY 17  (ATHENS, TX)
U68  NDB RWY 09  (COWLEY-LOVELL-BYRON, WY)
U76  NDB RWY 28  (MOUNTAIN HOME, ID)
X50  NDB RWY 18  (NEW SMYRNA BEACH, FL)


Is there an explanation for the measurement system used in aviation?

To quote from the Wikipedia article on the subject:

  Although the unit knot does not fit within the SI system, its
  retention for nautical and aviation use is important because standard
  nautical charts are on the Mercator projection and the scale varies
  with latitude. On a chart of the North Atlantic, the scale varies by a
  factor of two from Florida to Greenland. A single graphic scale, of
  the sort on many maps, would therefore be useless on such a chart.
  Since the length of a nautical mile, for practical purposes, is
  equivalent to about a minute of latitude, a distance in nautical miles
  on a chart can easily be measured by using dividers and the latitude
  scales on the sides of the chart. Recent British Admiralty charts have
  a latitude scale down the middle to make this even easier.[8]

  e.g. BA Chart 73, Puerto de Huelva and Approaches, 2002


Why does each part of span not produce equivalent downwash?

Why should non-elliptical wings not produce constant downwash over span? They do at one angle of attack, given a proper twist distribution so that the circulation distribution over span is elliptical.

However, once the angle of attack is different from that of the elliptical distribution, the change in local circulation varies in proportion to local chord. If the chord distribution is not elliptical, the new circulation distribution due to that angle of attack change is also not elliptical, and so is the change in local downwash angle.

Sometimes it is desirable to not produce an elliptical circulation distribution rsp. have an elliptical planform. If the objective is to minimise drag, it helps to reduce weight and pure lift/drag optimization is too narrow. What should count is the best ratio of lift minus wing weight relative to drag. R. T. Jones wrote a NACA Technical Note back in 1950 in which he looked at this problem analytically. Wing weight goes up when much lift is created near the tips, because this lift will cause a disproportional root bending moment, and the wing spar, which has to carry this bending moment, is a significant part of the wing structure. Therefore, reducing lift at the tips and adding more lift at the root will create a lighter wing for a modest drag increase, resulting in an overall optimum with an almost triangular lift distribution. When compared to an elliptical wing planform, the total wing span of such an optimized wing is bigger for the same overall drag, but this wing will weigh less.

Another example is wing stall. An elliptical wing without washout will have a constant lift coefficient over span, and Reynolds number effects ensure that the wing will stall at the tips first. An unsymmetrical stall will result in an accelerated roll departure: The stalled side of the wing loses lift, drops and sees an increase in angle of attack which worsens the stall condition. This effect gives an elliptical wing poor handling characteristics and is the reason why many GA aircraft have rectangular or trapezoidal planforms of little taper.


Does the retirement age for commercial airline pilots vary across the globe?

Yes, they do vary between different countries. The international standard for regulations is created by ICAO, but member nations are free to deviate from ICAO rules and several do. ICAO currently limits retirement age to 60 for single-person crew, 65 for multi-person crew, and an exception to 70 for balloon or sailplane.
EASA did a study in 2019 in response to requests from countries to increase the age for single-person helicopter crews to 65. The link to the actual report is broken, but there is a summary posted on the ICAO website. The rationale from these countries is that standard retirement age in those countries is 65. The report lists a few large agencies that deviate from the ICAO standards. Japan raised their limit to 68 for multi-crew ops. Canada, Australia and New Zealand have no age limit, the latter two indicating that it would be considered age discrimination.


How does the F-35's roll posts work, and how does its engine turn down 90 degrees?

The purpose of the roll posts is to let the pilot have some control authority in hover and stabilization, along with controlling aircraft attitude. Basically, the Rolls Royce Lift System used in the VTOL F-35 has three components connected by drive shaft (along with the engine):

The LiftFan at the front
Three-bearing swivel module (3BSM), which turns the nozzle through 95$^\circ$, and
Two Roll posts on either side of the fuselage.

F-35 Liftfan system; image from nationstates.net

Basically, some bypass air is directed towards the (individually adjustable) roll post ducts to ensure stability during hover, which is done by the onboard computer. In this image, you can see the roll post doors opening on outboard sides of the MLG doors.

F-35 roll post doors opening; image from nationstates.net

The 3-Bearing Swivel Module (3BSM) has three segments driven by two actuators (the first one drives the first segment, while the second one drives the second segment directly and the third one through an angle gearbox). The three segments are cut at an angle, so that when transferring from forward flight to hover, the central segment ends up with its longer edge at the top (so that their sections with maximum length are on the same side), thus 'summing' the bearing offset angles to give a 95$^\circ$ deflection of the jetpipe nozzle in the downward direction.

From codeonemagazone:

  The three-bearing swivel nozzle, 3BSN, design uses three segments of the engine exhaust duct cut on an angle and joined by two airtight circular bearings. External motors drive geared teeth in these segments to rotate them to create the deflected thrust. The forward and aft segments always stay aligned with one another in the rotational axis. The center segment rotates through 180 degrees relative to them. The third bearing is on the back of the engine aft of the turbine stage and provides the ability to swivel the nozzle thrust axis in yaw at any pitch angle.

Three bearing swivel module, from codeonemagazine


What is the fuel source for the APU on a B737?

It comes from the left side of the fuel manifold, which means it is most often fed from the #1 main tank, typically by turning on either or both boost pumps in that tank. However, it can be fed from the center tank (using the left center tank boost pump) or from the #2 main tank using a boost pump there and opening the crossfeed valve.

If no boost pumps are running, it suction (not gravity) feeds from the #1 main tank. This would be the case when starting the APU with only battery power and no external AC power. It isn't preferrd to do this for longer than necessary, though, because it puts more wear on the fuel control unit with the suction feed than when the fuel is being supplied from a boost pump.

There is no separate fuel tank dedicated to the APU. Gravity feed wouldn't work because the APU is higher than the main tanks (in the wings) and the center tank (below the cabin floor).  (The exception to that would be if the aircraft is inverted, although that situation is considered undesirable for several reasons unrelated to providing fuel to the APU.)


Why can't Centre of pressure and Centre of Gravity coincide?

Centre of pressure (CP), by definition, is the point at which the aerodynamic moment of something is zero.

If you are talking about the CP of the whole airplane, then at trim condition, the CG must always coincide with its CP. Period. This is achieved for any operational speed through well designed pitch control that varies in flight. For example, stabilizer/elevator for tailed airplanes, elevons for flying wing.

If you are talking about the CP of a single aerodynamic surface, like a wing or tail, then it gets more nuanced. Let's restrict the discussion to pitching moment only. First of all, CP is not a very useful measure of stability: it always moves around for a cambered airfoil. In fact, at an AOA where the lift is zero for a positively cambered airfoil, it moves to infinity!

Instead, use aerodynamic centre (AC) for stability analysis. For pitch stability, you would like the CG to be ahead of the AC of the entire airplane (this is called the neutral point).


Do modern airliners have a flaps warning indication?

It could have been as you witnessed.

In 2005, a modification package dubbed Quiet Wing was offered for the 737-200 and the 737 Classic (-3/4/500) that would droop the flaps by 4° for all phases of flight.

  [It] decreases drag for cruise, and increases the aerodynamic efficiency of the wing by between 2% and 3%.

The NTSB in 1981 also found that many 727 pilots were doing the same thing in cruise—but manually and unapproved. They would pull a CB to keep the slats on the leading edge of the wing retracted, while the flaps extended to the their first stop.

  Investigators believed that 727 pilots (in general, and this flight specifically) were setting the trailing edge flaps to two degrees during high altitude cruise, while at the same time pulling the circuit breaker for the slats so that they would not activate. This configuration was rumored to result in increased lift with no increase in drag, thus allowing more speed, higher elevation, or decreased fuel consumption. Flaps and Slats were intended to only be deployed at low speeds during take-off or landing.

To answer the title question, yes. Flap position indicators exist, and combined with the electronic speed tape, the maximum speed indicated will be slower.

If the flaps were to be extended at above design speed, an overspeed warning will be triggered as well.


Will a quad fan arrangement on an aircraft help with pitching moments during VTOL flight transition?

The Doak VZ-4 twin ducted propulsor flew in 1958, the Bell X-22 took that up to four in 1966. So yes, people have been thinking about it for over half a century.
Analogously to any tailless aircraft, the side-by-side twin is sensitive to CG in vertical mode and trim must be closely maintained. Although not ducted, the Boeing V-22 Osprey convertiplane suffers from this issue. It is not often an operational limitation, but it does need crew/staff training and careful management.
Similarly the quad arrangement brings the same benefits as the tandem wing in allowing a wide range of CG positions. However the quadrotor does not scale well to full-size aircraft, as discussed at Why haven't quadcopters been scaled up yet?


Why do 20-series Learjets have such an extreme susceptibility to mach tuck?

The early series 20 Lears have always had boundary layer separation issues, so much so that any time the wings are removed and reinstalled the aircraft must be test flown. Mach tuck is an issue with all aircraft capable of trans-sonic flight, but on the early Lears this is apparently exacerbated by the susceptibility to boundary layer separation from the laminar flow airfoil.

To address this and other shortcomings in the 20-series wings, a number of modifications have been developed. Vortex generators were installed in front of the ailerons, and then a boundary layer energizer "fence" was developed. Dee Howard and Gates Learjet jointly developed a "cuff" for the Lear 25 wing that resulted in the 25G variant, with better performance at cruise and an increase in range of some 360 nautical miles.

There has been some talk that the problems of the Lear wings come from the FFA P16 design. Bill Lear's son has clarified that his father did not use the P16 as the basis of the Lear 23. The two aircraft use different, though similar airfoils.


Is there a conventional notation or name for the slip angle?

Sideslip angle is commonly notated as β (see e.g. https://en.wikipedia.org/wiki/Slip_(aerodynamics)).


Do commercial airliners have the tail number placed somewhere on a placard in the cockpit?

Yes, on a commercial airliner typically the tail number and the SELCAL (if so equipped) are placarded on the panel.  It's hard to find sometimes in picture because it may be behind the yoke, but it should be there somewhere.


How does increasing the size of a jet engine make it more fuel efficient?

The efficiency issues are as follows.

For a fixed amount of mass flow rate through a work-extracting thermodynamic process, one large engine is more efficient than two smaller ones because the pair of smaller engines present more interior surface area relative to the mass flow through them than the single larger engine. The more wetted area inside the engine relative to the mass flow, the greater will be the frictional losses. This drives the designer toward fewer and larger engines and away from more numerous and smaller engines.

In addition, there are aerodynamic losses associated with each engine nacelle/pylon assembly on the wing which are minimized by reducing the number of engines installed per wing.


Should I record my helicopter and autogyro time in separate logbooks?

In the United States, except for that time which is used for certification or currency, the FAA permits you to log your time however you like, or even not log it at all.  That means that you can do pretty much whatever you feel like.

That said, here are my personal recommendations in order of how much I support them:

Get a digital pilot logbook. Log everything in it.
Get a professional pilot logbook with plenty of space for various categories and classes of aircraft. Copy all of your records from your old logbooks into it. Archive your old logbooks in a safe location. Use your new logbook for everything from here on.
Get a professional pilot logbook with plenty of space for various categories and classes of aircraft. Don't copy all the records from your old logbooks into it, just carry forward the totals. Archive your old logbooks in a safe location. Use your new logbook for everything from here on.
Get one logbook for each category/class of aircraft you intend to fly. Log your time in whichever logbook is appropriate. Remember which logbook is which. Keep them all easily accessible rather than storing them in a safe location. Worry about whether you lost one. Have a complicated system of adding up your totals from various logbooks. Make it difficult to look up flights chronologically. Feel sad.