What is the correct procedure to deal with a TCAS RA during intercept?

The correct procedure for the interceptee would to follow the TCAS Resolution Advisory as they have generally no idea that they are being intercepted.

The interceptor must ensure that no TCAS RA is generated by switching his transponder to the appropriate mode. This has been standard procedure since the introduction of TCAS.

TCAS works by interrogating other aircraft's transponders. These interrogations are done in both Mode 3/A and Mode C as well as in Mode S (UF-0). To ensure that no TCAS RA is generated the interceptor's transponder must not reply to Mode C and Mode S interrogations from the interceptee. Since the source of Mode C interrogations is not encoded in the interrogation, the transponder must not reply to any of these interrogations including those from radar.

Technically a transponder could be designed to selectively not reply to Mode S interrogations from the interceptee only, however I think it is common to switch off TCAS Mode-S replies, or even switch  off Mode S entirely.


What was the first aircraft fitted with both an FDR & CVR?

It's not easy finding out which aircraft rolled-out with the first standard CVR/FDR combination. In fact it's so hard Google thought I was a robot, maybe I am.
Here's why, first this piece:

16 July 1964
COCKPIT voice recorders that will record all flight-deck conversations between the crew and ground control will be required in large passenger aircraft under new rules issued by the Federal Aviation Agency. Designed to assist in accident investigation and prevention, approved cockpit voice recorders will be required by July 1, 1966, in jets and turboprops weighing more than 12,500 lb. Pressurized four-engine piston aircraft will have to meet the requirement by January 1, 1967.
The installation of cockpit voice recorders supplements the existing requirement for critical-data flight recorders on similar aircraft. The latter, says the FAA, have been found indispensable in helping investigators determine probable accident causes, thus aiding development of ways to prevent accidents.

FDR's preceded CVR's and were already standard equipment on jets and turboprops weighing more than 12,500 lb. Then came the above CVR mandate to take effect by July 1966.
But, the CVR was not a new invention, and was already fitted to many aircraft, in fact, five months before the above piece we find this:

6 February 1964
Trans Canada Airlines has taken a world lead by announcing that it will spend \$1,360,000 to equip all its 78 aircraft with maintenance recording equipment. The airline has been investigating the use of the Royston Midas system for more than a year and last October took the decision to equip its fleet. Final details of the actual installations are now being decided, preparatory to placing a firm order, some additional steps having been taken as a result of the DC-8 accident at Montreal last November. TCA are to have a 93-channel system covering engines, movable surfaces, hydraulic and electrical systems and 15min of cockpit voice, installed in a safe location in the tail of its DC-8, DC-8F, Vanguard and Viscount aircraft. The installation will cost \$20,000 for each of the larger aircraft and \$15,000 for each Viscount and will be performed at Montreal and Winnipeg.
Next airline to place a major order for Midas may well be TWA, who have been conducting a systematic and successful investigation of its application for some time. The RAF first equipped one Britannia of Transport Command and has now ordered five recorder systems and four complete playback installations, presaging much more extensive adoption. British United Airways have also been flying a Midas-equipped Britannia for some six months.

Trans Canada Airlines being the first to equip a CVR/FDR/QAR combo well before the FAA mandate.
The CVR being an Australian invention, some sources say CVR's were required in Australia before the US, but given how many aircraft manufacturers were there in the mid-60's, it's near impossible to know which one was the first.
No one was eager to market their plane as the first that tells you why you crashed.
Most articles I found from the 60's were CVR manufacturers promoting their new products, but no aircraft manufacturer mentioning them. Example below:

Source used: Flightglobal Archive


Would an aircraft with no ailerons, no elevators and no rudders be safely flyable?

An interesting thought. Control the aeroplane through its propeller(s), like a helicopter does.

Propeller torque differential would control roll
Propeller cyclic would control both pitch and yaw
Propeller collective would control engine thrust, like already done in constant speed propellers.

The thing that immediately comes to mind is moment arm for pitch and yaw. Helicopter blades are relatively long, and the rotor is mounted about halfway along the fuselage. The prop is limited in its blade length due to ground clearance.

With a configuration like above, longer propeller blades can be mounted so the pitch and yaw moment arms can be extended. As @Sanchises points out, placing of the propeller like this creates a coupling between pitch and thrust - not a bad thing, increasing pitch controllability by controlling thrust. A strong nose wheel might be required for take-off.

Not sure about your reference to the skydiving Kamov, but the aircraft could glide down after engine failure while keeping enough RPM to control cyclic. It would be a bit draggy though, with the drag comparable with a parachute of the same diameter as the propeller. Autorotation works best with a large blade moment of inertia, and the propeller would definitely not have the optimal blade length for that.


What made 800 feet and later 1,000 feet attractive as the standard traffic pattern altitude?

The traffic pattern altitude (and the pattern turn direction) is set by the airport owner in coordination with the FAA. Refer to section 8.

Airport traffic patterns are often 1000 ft. AGL today. In recent past, the typical altitude above ground level was 800 ft. Flying Magazine, in a September 1958 article states:

  Under VFR conditions proper entry into the zone is sadly neglected. Before you enter the control zone you should be at the Pattern Altitude which is more or less standard rule at every airport in the country--800 to 1,000 feet for light aircraft, 1,200 to 1,500 for heavy or fast aircraft. This provides you with altitude, yet gives plenty of room to make your turns. Letting down in traffic makes you vulnerable and blind, at the same time increasing the odds of hitting someone you will never see"

Experts and non-experts seem to agree an altitude increase would be beneficial:

Better noise abatement near the airport environment
Increasing tower heights
1000 is easier to remember than 800

Fun facts:

Tangier island/KTGI airport elevation is 6 ft mean sea level. The traffic pattern altitude is 605 ft.
Truckee/KTRK is 5901 ft. MSL with an 1100 ft. TPA.
Sedona/KSEZ is 4830 ft. MSL. The TPA is 1173 ft.

Pilots flying into Sedona must be precise, haha!


What course should be taken to make estimated calculations?

I would calculate that leg in two segments.  From GIJ to BENJO flying a course of 082 magnetic (50 NM), thence from BENJO to CRL on a magnetic course 087 (79 NM).

In addition, the magnetic variation is only applicable to hand plotting an arbitrary course using the map's orientation as a reference; IFR charts list true magnetic courses on their airways for ease of reference.

After that, you just need the winds aloft and you're off to the races!


Why is the Airbus Beluga XL based upon the A330, and not upon the A350 or A380?

Considering that (one of) the main reason(s) for introduction of larger Beluga XL is to meet the demands of the A350 XWB production, it doesn't make sense to have a modified A350 for the next transporter: Airbus would prefer to sell A350s to customers than to modify them for internal use.
A380 is not supported by airports near most of the Airbus production centers- defeating the very purpose of having the Beluga XL fleet.
In the end, it boils down to which aircraft can satisfy two requirements- payload and runway capability at Broughton. From caan.asia/en:

Airbus wants an aircraft which not only meets high payload capabilities - including capacity to carry two fully-fitted A350 wings - but can operate within airfield landing limitations at its UK wing facility at Broughton, to which it will deliver A350 wing covers. Broughton's declared available landing distance for the shorter runway 04 approach is 1,663m (5,460ft).
Airbus considers this restriction to be too tight for a modified A330-300 or A340-500, while the payload requirement is too high for an A300-600. It believes an A330-200 variant - tentatively designated the A330-200XL - could potentially cope with the landing criteria at projected weights of around 135t, and is the most promising option.

Boeing Dreamlifter, on the other hand, is purpose built for B787 transport- wings and fuselage, while the Beluga transports only the wings. The distances involved in the B787 production (compared to the only European production centers of A350 XWB) means that Airbus can afford to transport only the wings, rather than fuselages too.


What are the advantages/disadvantages of ultrasonic in aircraft structure inspection?

Ultrasonic inspection is perhaps the most widely used inspection procedures in aerospace to detect subsurface anomalies.

Portability- A number of portable ultrasonic equipment are available, which are very simple and are widely used.
The detection depth for flaws is far superior compared to most other NDT methods.
It can be used for detecting flaws even if only one surface of the part is accessible (simply use pulse echo method).
The results are more or less instantaneous- Usually there is no waiting time involved as the results are displayed in a screen.
The time required for preparation is very less; usually the part is cleaned and the couplant applied; after the inspection, it can simply be wiped off.

However, just like any other (NDT) method, this too has its own share of disadvantages:

It is very difficult to use this method for parts which are very thin- for e.g. the aircraft skin because of the dead zone, though this can be overcome by using higher frequencies or immersion technique; in most cases of aircraft checks, this may not be an option. Also, it cannot be used for irregular and non-homogeneous parts (At-least, not the portable methods).
The method does not detect flaws that are oriented parallel to the wave propagation.
The material must be characterized prior to inspection. As the returning  signal is affected by attenuation within the material, comparisons can be made only if a similar (defective and good) specimen of same material is characterized first.
Usually, Ultrasonic method requires a trained operator for interpretation of the results.

As far a full aircraft is considered, only some critical parts are tested using ultrasonic (or other NDT) methods. There is no way to check the entire aircraft except by thorough visual inspection.


Do helicopters have trim? How does it work?

It depends on what you mean by trim.

If you mean a a mechanism that allows the pilot to reduce the control forces in order to allow the helicopter to be flown hands off, then the answer is a qualified yes.

If you mean a trim tab attached to a control surface, then the answer is no. Many airplanes which have a trim control do not use a trim tab. For example, Pipers have an anti-servo tab on the elevator, which the pilot uses to reduce control forces.

Since helicopters are unstable -- meaning if you take your hand off the cyclic the aircraft will be in an unusual attitude within a second -- nothing short of electronics and actuators will allow a heli to be flown hands off.

But every heli except the smallest ones, have considerable stick forces, which make them difficult to impossible to handle without some kind of assistance.

The simplest setup is what you find on the original 4-seat R-44 Astro, which lacked hydraulic assist. On top of the cyclic you will find a 4-way "hat" switch which uses electrical actuators on the cyclic to reduce the control forces necessary to fly it.

Larger helicopters have hydraulic assist, which allows the copter to be controlled with just two fingers. Inop hydraulics is considered an emergency.

Big helicopters have a stability augmentation system, which allows the helicopter to be flown hands off. An SAS is required for IFR flight.


Does it really take 9000 feet to recover from a spin in a P-51 Mustang?

9000 feet is not likely if the pilot applied recovery techniques in a timely manner.

US Army Air Force spin tests found here resulted in an average of 3000-6000 ft alt loss. There are several memos on it all resulting in similar figures.

This one dated 6/26/1943 shows 5500 feet for P-51A

This one from 4/30/1944 shows 3000-6500 ft for P-51B

The longest drop noted was on this memo from 7/10/1943 on the P-51A which indicated a single occurrence where the pilot modified his recovery technique resulting in a drop of 7500 ft.


Calculating CL and CD from Cp vs. x/c graph data?

You have done it correctly. Only mistake appears to be swapping the CL and CD value.
Being said that, for the info, this CD mearly is a numerical error due to ds being finite as invisvid flow drag is zero.


What prevents a passenger from opening the emergency door on his own will, mid-flight?

At cruising altitude there is between 4 and 8 tons of pressure acting on the inside of the door. There aren't too many passengers capable of exerting that much force on the handle (and even fewer handles that won't just snap off). Latch type doors have interlocks or over-center latches that prevent operation with a pressurized cabin.

It's theoretically possible to open the over-wing exits at approach altitudes when there is no pressure differential. Other than being windy/noisy it would not affect the flight in any way. Cabin doors usually open forward, good luck pushing them open against the airflow. If the person who pulled the window plug wants out, it's their (and only their) funeral. I've sat in the open doors of light aircraft in flight hundreds of times, legs in the breeze, no seatbelt, while the plane makes fairly steep turns toward the open door side. It's not a problem.


Can a pilot use legal psychoactive cannabinoids?

Delta-8-Tetrahydrocannabinol (Delta-8-THC, Δ8-THC) is a cannabinoid found in the cannabis plant. It has psychoactive properties; the effects are less potent but comparable.
Delta 8 THC metabolites trigger many drug tests looking for Delta 9 THC metabolites. These compounds are chemically similar.
Whoever needs to pass a drug test (pilots included) should not take them.


Procedure for simulating nonlinear flight dynamics

I am not a flight dynamics expert, but let me give an extremely general answer on verification of a non-linear dynamic system.  consider that you have the non-linear system $\dot x =f(x)$.

This system may have multiple equilibrium points, which are the $x$ values such that $f(x)=0$.  You have checked that one of the desired equilibrium points is actually an equilibrium point in your simulation. So that's good.  But does your system have more than one equilbrium point?  if so, you probably want to check all of them.

Next, you want to check the stability of the equilibrium points.  You've checked that $f(x)=0$ for one equilibrium point.  You need to check what happens for a small perturbation say $x_0= x+\epsilon$.  If the equilbrium point is supposed to be stable, then you need to check that after some time, the system has returned to equilibrium.  If the equilbrium point is supposed to be unstable, you need to check that the system has diverged from the equilbrium point.

But even that is not good enough.  You also need to check the rates of convergence or divergence.  i.e. near the equilbrium point, you can linearize the system and find the eigenvalues.  i.e. if you are at a small perturbation away from a stable equililbrium, you expect the system to approach equilibrium at a certain rate, say $x=x_0 e^{-\lambda t}$.  You need to verify that the simulation matches the expected rate.

So to summarize, you need to verify that your simulation has the correct number of equilibrium points, that the stability of each equilbrium point is correct, and that the eigenvalues near each equilbrium point are correct.


Is "balanced field" defined with or without an engine failure?

It refers to the case with an engine failure.

The balanced field length is exactly equal to the accelerate-stop distance and the accelerate-go distance, if the V1 speed is chosen, where those two distances meet:

  2.3.1.3 Balanced Field Defined

  [...]

  The Continued Takeoff—After an engine
  failure during the takeoff roll, the airplane
  must continue to accelerate on the remaining
  engine(s), lift off and reach V2 speed at 35 feet.
  The later in the takeoff roll that the engine
  fails, the heavier the airplane can be and still
  gain enough speed to meet this requirement.
  For the engine failure occurring approximately
  one second prior to V1, the relationship of the
  allowable engine-out go takeoff weight to V1
  would be as shown by the “Continued Takeoff”
  line in Figure 10. The higher the V1, the heavier
  the takeoff weight allowed.

  The Rejected Takeoff— On the stop side of the
  equation, the V1/weight trade has the opposite
  trend. The lower the V1, or the earlier in the
  takeoff roll the stop is initiated, the heavier the
  airplane can be, as indicated by the “Rejected
  Takeoff” line in Figure 10.

  The point at which the “Continued and Rejected
  Takeoff” lines intersect is of special interest. It
  defines what is called a “Balanced Field Limit” takeoff.
  The name “Balanced Field” refers to
  the fact that the accelerate-go performance
  required is exactly equal to (or “balances”)
  the accelerate-stop performance required.

(FAA Pilot Guide to Takeoff Safety, emphasis mine)

The continue case (accelerate-go) assumes an engine failure one second prior to V1.


Are larger airplanes more likely to stall?

Even assuming the same airspeed, a larger chord would increase the free-stream Reynolds number. As a general trend, higher free-stream Reynolds number will delay the stall boundary due to earlier transition to a turbulent boundary layer, as can be seen below for a 2D section data from wind tunnel:

Image ref: NASA Contractor Report 4745

This answer has a different and equally good illustration of the effect in terms of lift curves.

Of course, things get more nuanced in 3D, whether the airfoil is optimized for natural laminar flow, and in transonic flow, where the maximum lift trend with Reynolds number can reverse at an intermediate Reynolds number.


Is it legal to make a non-military stealth plane?

Yes you may, but you need to carry a mode C transponder while above 10,000 ft or in some types of controlled airspace and have it switched on. Which pretty much negates the stealth capabilities of your aircraft.

To quote the linked AOPA page:

  According to 14 CFR 99.13, no person may operate an aircraft into or
  out of the United States, or into, within, or across an ADIZ
  designated in subpart B unless operating a transponder with Mode C.
  Certain exemptions might apply to aircraft that were not originally
  certified with an engine-driven electrical system; see 99.13(d).


Are checklists always written in English?

It is definitely common here in Germany to use German checklists (German is not an ICAO language).
see http://www.motorflugschule-egelsbach.de/Downloads/Diverses/C172_R04.pdf for example.

However since many systems and acronyms used have English terms anyways it boils down to a combination with English.


Under which condition is a forward CG most critical?

One intuitive way to think about this is that the pitching motion of a rigid body occurs at its CG. At forward CG, the elevator, which pitches the aircraft up, indeed has a longer moment arm. On the other hand, however, the wing lift vector, which tends to pitch the aircraft down, also has a longer moment arm. The proportion of change of the wing lift moment arm is quite a bit more than that of the elevator, for the same change in CG. In the end, the wing lift, which is also quite a bit larger, wins this race. Hence, forward CG is more critical for maneuvering.

Strange that it says landing, which I assume is the flare portion, is the most critical condition. I would've thought takeoff rotation would be equally bad, especially if you have a mistrim.


What does a 10nm/20nm circle on instrument approach charts mean?

It can be 20 km, or 10 NM.

Since you've shown an ICAO-style plate, ICAO Annex 4 Aeronautical Charts says:

  11.3.3.1 Except where this is not practicable, a distance
  circle with a radius of 20 km (10 NM) centred on a DME
  located on or close to the aerodrome, or on the aerodrome
  reference point where no suitable DME is available, shall be
  shown; its radius shall be indicated on the circumference.

So whenever possible, this circle must be shown.


How should a helicopter pilot react after V-belt breaking?

A number of R22 accident reports indicate that the rotor RPM drops and the engine will tend to overspeed in case of 'V' belt failure. From the Australian Transport Safety Bureau report Reliability of the Robinson R22 helicopter belt drive system:

NTSB occurrence report: LAX92LA034
... pilot reported that the engine RPM indicator suddenly pegged at the top of the gauge and the rotor RPM began rapidly decreasing. ... Examination ... revealed that the forward v-belt was split longitudinally and displaced from the transmission pulleys. The rear belt was found off the engine and transmission pulleys.
CAA occurrence report: 99/23
... there was a bang and the engine ‘revved up’, but power to the main rotor was lost. The power loss to the main rotors was due to broken v-belts.
NTSB occurrence report: NYC08LA043
... , the engine’s RPM sharply  increased and the main rotor RPM alarm sounded. Post-accident examination of the helicopter drive system revealed that the v-belts had rolled off the sheaves
NTSB occurrence report: N993KC
The pilot ... heard a loud ‘bang’. The pilot ... observed the engine RPM was excessively high, the rotor RPM was below 80 percent and the low rotor
RPM warning horn was sounding. The on-scene investigation noted that one of the v-belts to the main rotor drive system had separated,  which caused the other belt to slip off the upper spindle.

In case of suspected belt failure, the pilot is expected to try and make a power on landing while prepared for an autorotative one. From the R-22 Flight Manual:

... if the clutch light flickers or stays on for a longer time than usual,  it can indicate a belt or bearing failure in the vee-belt  drive. If that occurs, immediately pull the  CLUTCH  circuit breaker. Select the closest  safe landing  site and make  a normal power-on landing. Be prepared  to  enter autorotation should failure of the drive system occur. The smell of burning rubber may also indicate an impending belt failure.

Note that there is no talk about the throttle. Though the R22 has two V belts, it is not designed to fly with a single one (though there seems to be some instances of that). My guess is that it is better for the pilot not to tinker with the throttle for two reasons- if the problem is somewhere else, reducing the rpm would have adverse effects and if the belt is indeed gone, it would be better for the pilot to concentrate on saving the people first and the engine later.


Will talking about sleep problems with my doctor jeopardize my medical?

In the US the HIPAA rules often provide you with confidentiality but there are several circumstances that allow your doctor to provide info without your consent and being a pilot qualifies. It allows them to, but only requires them to in situations where a crime might be involved, i.e. physical abuse.

The concern would probably not be that your doctor will tell the FAA (although they probably could if they were truly concerned), it would be that you would be required to tell your FAA examiner of any diagnosis. I believe it's a felony not to.

If it's sleep apnea he's concerned about (you said sleep problem, non-narcolepsy - I'm not a doctor so I'm just offering what i know about a very common sleep problem) then there are ways to get a special issuance medical certificate.

I'm not a pilot but a driver and I have to have a DOT medical card. The way sleep apnea is usually treated is by CPAP. For the DOT physical, If you are on CPAP you have to bring the machine to your physical so the examiner can check the data and verify that you have been using it (I think 75% of the time but don't quote me on that). I checked and the FAA has similar rules.

I agree with Pondlife that one's health should trump licensing concerns, and nobody should be flying if they are at risk of dozing off. But I definitely understand your friend's situation. I suspected I had apnea but I refused to go to a sleep study because I did not want the diagnosis. What if I couldn't deal with CPAP? My dad was on CPAP for 30 years but he rarely used it because it was too uncomfortable. Then I'd be forced to use it to keep my job.

Fortunately my situation resolved itself (I don't have apnea) but I understand why he's reticent to mention it to his doctor.


What equipment qualifies as FAA-acceptable for providing "Supplemental Oxygen"?

An even more important question than how is how much oxygen to take, but there's no specific FAA guidance or regulation on either point. Different aircraft can carry different equipment, and people have different requirements depending on their age, lungs, blood chemistry, whether they smoke, day vs. night etc. The FAA's guide on oxygen equipment for GA use is extremely limited and although it describes a range of equipment types it doesn't mention any specific requirements.

Having said that, the 'usual' approach seems to be to use a pulse oximeter to measure your oxygen saturation and if it's too low then go on oxygen immediately, regardless of altitude or other considerations. The moderator of AOPA's medical forum is an AME and he recommends oxygen use any time your saturation level drops below 90%, which is apparently also the required level in hospitals for a patient to make an "informed" - i.e. clearheaded - decision.

But returning to the question of equipment, there aren't any regulations on this at all, so provided that the equipment is safe to use in the aircraft (including not obstructing exits and so on) and not illegal under any other law that might apply (carriage of dangerous goods or whatever) then you can go for it. But the usual 'always act as if you'll have to justify your decisions to the FAA tomorrow' advice applies here, IMO, and personally I would always go with an aviation-specific setup if I needed one.


How to detect landing and takeoff using the value of GND field in ADS-B messages?

There is no field in any of the eight message types that indicates that an aircraft is in the process of either landing or taking off. Field 22, where it is transmitted, is a simple binary status: the aircraft is on the ground, or it is not. If you want to know what an aircraft is doing look at values for field 22 in successive messages. When the state changes you'll know that an aircraft has transitioned from ground to not-on-ground and has taken off (or vice versa)

Depending on how you define it, the actual period for which a 'taking off' status would be valid could be very short. I.e, just the duration of the take-off roll. Before that the aircraft is taxying and on-ground; after that it is flying. The same limitation is true for landing, but in reverse.


What is the average time taken to load and unload the luggage?

Passengers' luggage is not loaded in an A380 by one suitcase at a time. That would be very time consuming.

After passengers check in the luggage and head towards the gate where the superjumbo is parked, their baggage is started to get stored in unit load devices1. And after that, those ULDs are loaded into the airplane:

Image Source

According to Airbus, the A380 can store 38 LD3s. Volume of a typical suitcase/bag (dimensions: 32"H x 12"W x 21"D) is less than 5 cubic feet, so 30 suitcases can easily fit in a single LD3.

Now let's talk about your questions about loading and unloading times. As A380s mostly fly on international routes, passengers are required to check in several hours before a flight's departure. But once they check in their luggage, the process of loading those LD3 starts, even if the airplane has not yet arrived at the gate. As soon as the airplane reaches the gate, unloading and loading processes start. These two processes are not as time consuming as they may appear2.

Passengers' checked in luggage is not loaded like in this manner (picture below). On a wide-body like an A380, this is the case of carry-on baggage which stored in the underfloor area, instead of overhead bins.

Image Source

1: A380 uses LD3, whose capacity is 159 cubic feet.
2: Note that after an LD3 is unloaded from an airplane, it might take another hour or even more for the passengers to get their luggage at the baggage claim area.


Why didn’t AFR4590 use heavy in its call sign?

The post When is 'heavy' used in callsign? shows that the usage of "Heavy" depends on the country.
The general ICAO usage is to say "Heavy" only in the initial message with a frequency.
That usage applies to France, where the linked CVR transcipt took place (no differences are listed in the French AIP). Since that transcript does not show the initial contact with tower, it doesn't show when "Heavy" was first used.
USA however deviates from this standard, and this difference from ICAO is listed in the USA AIP:

4.9.2 In the U.S., the word "heavy" is used in all communications with or about heavy jet aircraft in the terminal environment. In the en route environment, "heavy" is used in all communications with or about heavy jet aircraft with a terminal facility, when the en route center is providing approach control service, when the separation from a following aircraft may become less than five miles by approved procedure, and when issuing traffic advisories.
— https://www.faa.gov/air_traffic/publications/atpubs/aip_html/part1_gen_section_1.7.html

The general ICAO usage (4.9.2) can be found in ICAO Doc 4444:

4.9.2 Indication of heavy wake turbulence category
For aircraft in the heavy wake turbulence category the word "Heavy" shall be included immediately after the aircraft call sign in the initial radiotelephony contact between such aircraft and ATS units.


Why do military jets sometimes have elevators in a depressed position when parked?

It generally means that the hydraulic actuator (power control unit) driving the surface has an "idle" facility that allows fluid to move internally between the two sides of the actuator piston, or just circulate in the pressure/return lines, and when unpressurized it acts more or less like a hydraulic damper even though the input spool valve is at its "null" (no command) position.

The result is that when unpressurized it's free to move (although damped) and if gravity wants to pull the surface in one direction it'll do so.  As soon as hydraulic pressure is applied, it'll snap back to whatever position is being called for by the input system.

Sometimes you have PCUs that are "non-idling" and when unpressurized they are hydraulically locked which is only broken when there is a control input to the controlling spool valve.  Such surfaces stay where they are even when the hydraulic pressure has bled off, unless you move the controls to break the hydraulic lock.

On the CRJs, the elevator PCUs are idling, and the elevators sag when unpressurized.  The aileron PCUs however are non-idling, and the ailerons don't sag when unpressurized. If you try to move an RJ's aileron when its hydraulics are off, it is totally rigid.


What is the two-person cockpit rule, as of February 2020?

As for the EU, EASA has published SIB 2016-09 which states that: (emphasis mine)

  CAT.OP.MPA.210 of Regulation (EU) No 965/2012 stipulates that flight crew members required to be on duty in the flight crew compartment shall remain at the assigned station, unless absence is necessary for the performance of duties in connection with the operations or for physiological needs, provided at least one suitably qualified pilot remains at the controls of the aircraft at all times.

  In such cases, the Agency recommends operators to assess the safety and security risks associated with a flight crew member remaining alone in the flight crew compartment.
  This assessment should take the following elements into account:

  1) the operator’s psychological and security screening policy of flight crews;

  2) employment stability and turnover rate of flight crews;

  3) access to a support programme, providing psychological support and relief to flight crew when needed; and

  4) ability of the operator’s management system to mitigate psychological and social risks.

In other words, it is up to the individual airlines to decide if they want to implement a rule requiring two people in the cockpit at all time. It is not a legal requirement.


Is there a website that shows past flight tracks of a few days back?

If you just need a few days then FlightAware let’s you do that. I think it goes back 7 days for free. Past that you have to pay. That is for a particular flight. FR24 has a history feature that will play back the whole radar starting at a particular time. It plays back at 12x speed, though.

On FR24 you just open the main screen, move the map where you want it then click the clock icon on the right side. Enter the time and date you’re interested in. Note that it’s in UTC time, so you’ll have to convert your local time to UTC.

Then it will begin playing back. You can see the time and playback speed on a bar at the bottom of the screen.


What mechanism or design aspect prevents jet blast from escaping the front of a Ramjet or scram jet?

Pressure is the greatest just before the combustor in both jet and ramjet engines - therefore air would have against the pressure differential for this to happen (turbine only has therefore an indirect role)


Does thin airfoil theory work at very high angles of attack?

Of course not. Thin Airfoil Theory produces a beautiful result that relates the zero-AOA lift to the mean camber of the airfoil, as well as the lift slope vs AOA of any thin airfoil is $2\pi$. But that's assuming:

Airfoil is asymptotically thin: such that the mean camber line represents the flow path
Camber is close to the chord: such that the vortex sheet is assumed to lie on the chord while resulting in the flow path that lies on the camber line
AOA and camber are small: such that all angles are linearized ($\sin\theta \approx \tan\theta \approx \theta$); obviously at large angles, this assumption breaks down and the results are worthless
Potential and incompressible flow: by the virtue of irrotationality, stall will not be modeled.

So in all, the result is only valid for small range of AOA on an idealized thin airfoil. For engineering purposes on general airfoils, you'd want to use panel method + boundary layer equations. But even then, extrapolating results beyond stall lead to ridiculous results (certainly at 90deg or 180deg).

More details on Thin Airfoil Theory can be found in Drela, Flight Vehicle Aerodynamics or Anderson, Fundamentals of Aerodynamics.


What is the least expensive way to become a commercial pilot in the UK?

There's a finite minimum set of requirements you must meet to get that ATPL and type ratings, and there's a finite minimum cost associated with that.
Nothing's going to change that. The only thing you can possibly, maybe, change is who is going to pay that money.

So don't fail any of the tests. The ONLY way to reduce the cost is to complete the training in as short a time as possible. Which means minimising flight hours, simulator hours, and retaking of courses. All of which boils down to passing every test first try.

And it will still take tens of thousands of pounds.

Going the Air Force route is also takes tens of thousands of pounds, except the air force (and thus other people, taxpayers) pick up part of the bill.
Same with every other scenario in which you're not paying everything yourself. Someone, somewhere, is paying for it.
Used to be (and maybe still is, but it's unlikely given the glut of unemployed pilots) some airlines would take on people and train them from scratch. But that's now rare. Most at the very least require you to have your PPL already, and many won't hire you unless you are qualified on at least some aircraft in their fleet.


Can I bring a person with me while getting landing current if they're a licensed, current pilot?

As long as  you are not the legal pilot in command you can do what you want.  This means the other pilot has to be willing to act as the legal pilot in command on this flight.

  61.57(a) General experience.

  (1) Except as provided in paragraph (e) of this section, no person may
  act as a pilot in command of an aircraft carrying passengers or of an
  aircraft certificated for more than one pilot flight crewmember unless
  that person has made at least three takeoffs and three landings within
  the preceding 90 days, and—

  (i) The person acted as the sole manipulator of the flight controls;

The regulation is clearly required of the legal pilot in command.  If your current passenger is willing to act and take responsibility for your flying as the legal pilot in command then it is allowable.

Unfortunately, the other pilot is taking all the responsibility and gets none of the credit as they, under an airplane certificated for single pilot operations, cannot log any PIC time while you are getting current.

From LOGGING PILOT IN COMMAND TIME (FAA):

  However, two pilots may not simultaneously log PIC when one pilot is
  sole manipulator of the controls and the other is acting as
  pilot-in-command if the regulations governing the flight do not
  require more than one pilot.

If the other pilot is a CFI and it is a training flight then no one has to be landing current as there are no passengers.  See the Kortokrax interpretation.

Relevant excerpt:

  We agree that, for purposes of section 61.57(b), an authorized
  instructor providing instruction in an aircraft is not considered a
  passenger with respect to the person receiving instruction, even where
  the person receiving the instruction is acting as PIC. (The instructor
  must be current, qualified to instruct, and hold a category, class and
  type rating in the aircraft, if a class and type rating is required.)
  The instructor is not a passenger because he is present specifically
  to train the person receiving instruction. Neither is the person
  receiving instruction a passenger with respect to the instructor. This
  training may take place, even though neither pilot has met the
  61.57(b) requirements.


Would a gimbaled, always horizontal cockpit be beneficial to fighter jets?

With enough engineering (read, money), all sorts of things would be possible, but if you picture the aircraft in a hard, level turn, the g-forces would be pressing "down" relative to a conventional cockpit, but "sideways" for a cockpit that was gimbaled so the pilot was sitting upright relative to the horizon.  And that would probably be a lot harder to take than the usual "down" G-forces.  Resisting 9 G's pulling your hand and forearm straight down can be done with a support for your arm (side-stick controller) or a bit of a ledge at the bottom of the handgrip (side-stick or center stick), but keeping precise control of the aircraft with 9 G's pulling your hand sideways might be a lot harder.

Beyond that, the sideways G force would be pushing your head to the side, which probably ends up banging your helmet -- pretty hard sometimes -- against whatever restraint or canopy it meets.

Something that achieves some of the goals you mention is the "Virtual Reality" helmet of the F-35, where the pilot can essentially look through the airframe and "see" aircraft, targets, and whatnot even in places that he wouldn't have an actual line-of sight.  That allows him to look in any direction, reacting to threats, tracking his target, and so forth.  And without having to gimbal the cockpit.  Although for what the F-35's cost, that might actually be cheaper!


It's a Russian YAK-141

This was the VTOL prototype meant to compete with the Harrier and perform carrier-based work (note: edited for clarity)

  Designers from the Yakovlev bureau found out, that the double engine scheme of the Yak-38 and Harrier was not suitable for the new plane. Instead they created a layout with a single engine, that could turn 95° down, located in the middle of the fuselage, just behind the center of gravity. [Two additional vertical thrust engines] would turn on only during vertical take-off, vertical landing and hovering. Engineers had to stretch body of the aircraft for aerodynamic stability. This is why the Yak-141 is larger than its predecessor, the Yak-38.

The plane was never mass produced

  The Yak-141 multi-role fighter did not enter production. The funding for this program ceased in 1991 after a landing accident on the aircraft carrier, when one prototype landed during excessive side wind and was badly damaged. After collapse of the Soviet Union military funding was limited. In 1992 the Yak-141 program was canceled as it happened with many other promising weapon systems. Also by 1995 Russia decommissioned all Kiev class aircraft carriers, this plane was intended for.


Do aircraft use the majority of their fuel to overcome friction?

No, the majority of the fuel is wasted on inefficiency of the engine.

Internal combustion engines like turbine engines are not exactly energy efficient. Most of the fuel is wasted by running the engine. Only about 35% to 40% of the energy from the fuel is converted to propulsive energy.  The rest of the energy from the fuel (~ 65%) is lost on heating up the atmosphere directly, excess kinetic energy in the exhaust stream, internal drag & friction of the engine and producing noise.

The remaining ~35% the energy is there to overcome the work done by drag.

This drag can be split into lift induced drag and parasitic drag.
It can also be split into pressure drag and friction drag.
For simplicity assume that all the lift induced drag is all pressure drag, and all parasitic drag is friction drag.

Aircraft usually cruise near the speed where drag is lowest. In such a situation, 50% of the drag is induced drag and 50% is parasitic drag. In practice cruise speed is a bit above the minimum drag speed, so the parasitic drag exceeds the induced drag. If our earlier assumption is correct, then over 50% of the drag would be friction drag.

That would bring the total estimates to:

65% wasted
20% friction drag
15% pressure drag

For example the GE90, the engine fitted on most Boeing 777s, produces a thrust of 70 kN in cruise flight of 250 m/s at a fuel consumption of 1.08 kg/s.

The propulsive power delivered by the engine is $70 \cdot 10^3 \cdot 250 = 17.5\cdot 10^6 \textrm{W}$.

Jet fuel has a specific heat of $43.15 \cdot 10^6 \textrm{J/kg}$
The energy consumption of the engines is thus:

$1.08 \cdot 43.15 \cdot 10^6 = 46.6 \cdot10^6\textrm{W}$

That gives an efficiency of 37.6%. This may seem poor but it is one of the most efficient engines available today.

Data sourcePDF for thrust, speed & consumption:


How to handle seeing someone online claiming to be a pilot or pilot in training, who one feels shouldn't be flying, in the EU?

In general, one wouldn't.

If the user in question has never touched the yoke, there is no issue - it's not illegal to lie on the internet.
If they're in training, it's on their instructor to set them right.

This leaves the case where they do hold a current license. Presumably you want to notify the local aviation authority that they might not satisfy its requirements.

Now put yourself in the local FAA-equivalent's shoes. Supposedly a certified pilot has posted on the internet that the artificial horizon is a lie and one should always trust their gut over it. What recourse, exactly, do you have against them? They're not under any obligation to teach flying to the general public, and there's no regulations or prescribed penalties for publishing incorrect information on the internet.

NB: It would be very different had they identified themselves as a commercial pilot for a specific carrier. In that case, they'd be presenting their airline in a bad light, and the freedom of employment (in the US, varies in the EU) would allow their employer to take action to protect their reputation.

A PPL, OTOH, is a more exclusive cousin to the driver's license, and merely indicates that its holder has at some point convinced their instructor that they were capable of flying at that moment, while meeting a number of formal requirements, and has renewed it since at required intervals.

The forum's administration might want to take action to keep false information away from their board, if you inform them, but interaction with them is a subject far removed from aviation.


Why do turbofans have different nozzles?

The nozzle, apart from its main function, that is accelerating the air in order to propel the vehicle, it determines what goes into the front of the engine, it is a downstream restrictor along with the turbine nozzle.

The areas of both the propelling nozzle and turbine nozzle set the mass flow through the engine and maximum pressure. For different engine operational purposes, it is used one shape or another. These engines have different shapes due to optimization reasons; the engine, is designed in such a way that the aircraft features will have the best balance in terms of fuel consumption, thrust needed, and many other parameters.

Each manufacturer design their engines in the most convenient way and then, it is determined which engine is better for a given aircraft.

Different kind of geometries, (e.g. convergent-divergent) also affect on the engine operation regime (supersonic, subsonic, transonic), but this does not affect here since all the engines are turbofans and thus, subsonic.


Why do helicopters crash in low visibility (IMC)?

The only flight rule that will completely eliminate human error is to ban people from flying planes or programming UAVs.

More regulations won't solve this.  Aviation is already strictly regulated.

As for why the pilot did not climb, well, you will have to ask him.

Keep in mind that a mechanical failure could be to blame.

We just don't know.

Answer to the previous question:
The risks of continued visual flight into poor conditions are already pretty well documented.  It is a serious hazard for all flying machines, not just helicopters.  We don't know if that is what caused the crash or is even a contributing factor, though some of the makings of a CFIT accident are present (bad weather, possible perceived pressure to go, and possible complacency due to familiarity with the area).  Anything we say here, including what I just typed, is pure speculation.

We don't know why the helicopter crashed and we will likely never know for sure.  It was not equipped wIth a CVR or FDR nor was it required to be so equipped.

This is a tragic accident and that's all we know.


In what ways does the current FAA written exam differ from the Sporty's practice test?

I took the PPL written exam this morning (9/30/2016), but I used the Jeppesen PPL materials to prepare. Although I cannot speak to the Sporty's study materials, the Jeppesen practice exam and supporting materials were identical to the questions on the real exam. I would assume that Sporty's will be (almost?) the same. I actually scored higher on the real exam than on any of the practice tests.

Yes, the current exam uses the Airman Knowledge Testing Supplement for Sport Pilot, Recreational Pilot and Private Pilot booklet.


Does the cannon of the A-10 deliver more thrust than the engines do?

The A-10 uses a GAU-8/A. According to Wikipedia:

  The average recoil force of the GAU-8/A is 10,000 pounds-force (45
  kN), which is slightly more than the output of one of the A-10's two
  TF34 engines (9,065 lbf / 40.3 kN each). While this recoil force is
  significant, in practice a cannon fire burst only slows the aircraft a
  few miles per hour in level flight

Your statement is only partially true: two engines have more, but one engine has about 10% less thrust than the recoil force of the cannon.

The recoil force of MiG-27's GSh-6-30 was even larger: 60 kN.

As pointed out in a comment by @tj1000 the recoil of the GAU-8/A wasn't such a problem as the smoke from its shell propellant. If you're looking for the video mentioned in the comment (test pilot ejection due to engines out after firing ammunition with a new flash suppressor) this is the link (12:08-13:59).


How did Charles Lindbergh use dead reckoning over the Atlantic ocean?

It's actually "ded" reckoning (short for deduced), and it doesn't involve landmarks, it is simply flying a heading for a certain amount of time, that's it.  When you start adding in landmarks and things, that is called "pilotage."

Typically, visual navigation over land is mostly pilotage, with a bit of ded reckoning occasionally.  When you get over the water, like Charles Lindbergh, you do mostly ded reckoning.  When you do have a chance to use a landmark, you can update your location and basically restart your ded reckoning from a known point.  Lindbergh also used the stars to update his position and based new ded reckoning tracks on those positions.


What are the bumps in the F-22 Raptor wing for?

Yes they are fairings for the actuating mechanism for the control surface.  I can't speak directly to the F-22's details but, this kind of thing is done on lots of airplanes.  The F-22's control surface blister fairings are perhaps a bit more sophisticated and 100 times more expensive, but the concept isn't all that special.
The blister on the fixed structure will have an overlap with the blister on the moving element.  The blister on the moving element, like the aileron in the image below, will slip under the fixed part of the blister when it moves down, and there will be additional material forward of the joint that is exposed when the aileron moves up to maintain the contour.
In the somewhat grainy image, you can make out a dark line along the interface between aileron and wing that follows the profile of the blister (along with staining that could be discoloration from seeping hydraulic fluid).  There is likely a flexible seal strip to provide the smoothest possible transition but with enough compliance to accommodate the geometric changes in the surface contour, as the two halves of the bulge telescope with each other, and still keep the aerodynamic seal.

In profile it would look something like this:


If there was an engine malfunction, could we breathe contaminated air?

Yes, an malfunction in a jet engine can cause contaminated air to reach the passenger cabin. It is a rare occurrence, but it does happen.

One of the most famous cases was British Midland Flight 92 on Jan 8th 1989 in Kegworth England.

Kegworth air disaster

"After taking off from Heathrow at 7:52 p.m., Flight BD 092 was climbing through 28,300 feet to reach its cruising altitude of 35,000 feet when a blade detached from the fan of the port (left) CFM International CFM56 engine. While the pilots did not know the source of the problem, a pounding noise was suddenly heard, accompanied by severe vibrations. In addition, smoke poured into the cabin through the ventilation system and a burning smell entered the plane".

In addition to contamination from engine failures, there is a much more public debate over contamination due to perceived weaknesses in the design of the aircraft cabin air systems. These weaknesses have not been positively identified but many believe it is due to faulty engine seals and/or air conditioning packs. There are numerous reports of pilots, flight attendants, and passengers feeling ill from "toxic air" on aircraft.

The name "Aerotoxic Syndrome" is also used to describe the problem of bad air in aircraft. More information here: Aerotoxic syndrome

Here is a website dedicated to Toxic Cabin Air. Toxic Cabin Air


Are cargo and passenger flights flown differently?

Yes, cargo and passenger aircraft of the same basic model are sometimes flown differently when there is no live cargo. A friend of mine who flies cargo put it almost exactly as you did in your question when you say boxes cannot complain, so he sometimes hand flies the aircraft when passenger pilots would be required to use autopilot. Cargo pilots don't have to worry about tender stomachs in the back, so steeper climbs and descents and tighter turns are acceptable as long as the aircraft remains well within the flight envelope.


What instrument can be used to check that constant attitude is maintained?

Multiple choice questions are rarely about picking the only correct answer but instead often challenge you to pick the most correct answer out of a choice of 2 or more potentially correct answers.
I think that is the case here. While the VSI may well indicate to you that you are climbing or descending, it is unreliable for monitoring as it will be affected by small fluctuations such as up/downdrafts and lags quite a bit behind actual control input.
The altimeter, on the other hand, is quite stable and does not fluctuate quite so readily. If you're scanning and over a period of a minute your altitude has increased by 100 ft you can be pretty sure you're climbing - in that time the VSI may have indicated a climb, a descent and another climb etc. If you had scanned it while in a short-lived descent you might be fooled into thinking the long term affect was a descent. It was not - you were climbing overall.


Why can't runway 18 at Frankfurt Airport accept takeoffs or landings in the opposite direction?

Let us consider the operations other than takeoff on runway 18.

Takeoff Runway 36

There are buildings not far off the departure end and directly after the end of the runway is a movement area and ramp.  To safely takeoff they would have to clear that area and probably replace all the concrete with crushable concrete (more on this later).  The buildings probably post obstacle clearance issues for engine out climb performance.  The east-west runway north of 36 would have conflicting traffic and would have to be carefully sequenced.  Lastly, that purple area to the north of the runway is probably a noise sensitive area you aren't allowed to fly over at low altitude.
Landing Runway 18

You approach over a noise sensitive area, cross over operations on the northern east-west runway, overfly a building at extremely low levels (wheels on the roof) and have to make sure there are not airplanes on the ramp between the building and runway.  Landing short would be nothing short of disastrous and every landing would be a risky operation with the close proximity of airplanes and buildings.  Glideslope services would probably not be available due to ground obstacles.
Landing Runway 36

This is the least problematic approach.  The problem is in missed approaches and long landings.   There is no safety area at the end of 36 and a runway excursion past the end of the runway would be catastrophic.  To mitigate this they could re-pour the ramp concrete with crushable safety concrete, but that would probably make using ramp and building unsuitable.  If traffic goes around they conflict with aircraft on the northern east-west runway and have a noise sensitive area to deal with.

In comparison to the above, taking off to the south only requires a blast fence just north of the runway to protect the ramp and building from jet blast.  There are no logistic issues in aircraft movement on the ramp and the building is not in danger of being hit.


Which simulator is appropriate to learn the minimum to land an airliner?

The simple answer is: none.

Flying an airliner (never mind the difficulties of getting into a locked cockpit) is not just a matter of wrestling with some controls. And, unfortunately, you would indeed need to be "some sort of pilot" to do that, including "just" being able to "communicate with ATC and perform an auto-land".

Even if you were a qualified pilot of a different aircraft, you'd be staring at a sparkling ocean of "what the hell do these do" buttons, lights, knobs, switches, levers and other controls.

You might as well ask what kind of simulator would prepare you for playing first violin with the Vienna Philharmonic orchestra, or taking charge of a nuclear power station.

They are just not things that can be done without much study and training, without which you literally wouldn't even know what you are looking at.

This is quite sad, because I for one would be quite happy to be known as that person who stepped in and saved the day when the pilot/first violin/nuclear power station chief engineer was suddenly incapacitated.


what are the ways to avoid skidding off the runway apart from thrust reversers?

Your question appears to assume that thrust reversers are an acceptable way of keeping an aircraft from sliding off a slippery runway. While this may be true in rare cases, generally speaking you would NOT want to use reverse thrust to avoid skidding off a runway as that typically would exacerbate the problem.

Consider the following scenario: you have an icy runway and a strong crosswind from the right. As you start the takeoff roll, the airplane begins drifting left. You apply right rudder to correct, and the aircraft heading moves to the right of the runway direction. If you resolve the engines thrust vector into it's components relative to the runway centerline, you have most of the thrust propelling you down the runway, a much lesser amount propelling you toward the right side of the runway.

Lets say the left drift continues in spite of the engine thrust vector driving the aircraft to the right side of the runway, and you decide to abort the takeoff using reverse thrust. Thus, the thrust vector relative to the runway centerline will slow the aircraft. However the thrust vector 90° to the runway centerline will be toward the left side of the runway, which when added to your leftward drift will likely put you off the left side of the runway.

If you Google "tower air 747 crash" you'll see a number of entries concerning just such a scenario and the result. I found http://flightsafety.org/ap/ap_mar97.pdf to be the most instructive, although I do not wholly agree with the conclusions or with the narrative of what happened (a friend of mine was in the jumpseat right behind the captain, and I flew as a f.o. with that captain).

An obvious answer to your question is to never get yourself into such a serious situation. Can you wait for better conditions? Is another runway available? But if you MUST use a slippery runway for either takeoff or landing (or have already foolishly committed yourself), remember that if a runway is that slippery, it's feasible to continue down the runway in a manner that your course (the runway direction) doesn't match your heading. If the captain of the Tower Air flight had elected to do that, he might not have had the accident he did, or he might have had a much more serious accident. Tough call!


How is the lighting panel of an Airbus A340 designed and how does it work?

Nav and logo.

The logo light is a spotlight which illuminates the tail to show the airlines logo at night.  The Airbus A340 has two circuits for NAV/LOGO. Logo is an auto option when the landing gear is not compressed or the flaps are extended at 15º or more." in both positions, 1 and 2.

Dome is the cockpit ambient lighting.

Strobe on means the strobe is lit.  Auto means that the strobe is on when the landing gear is not compressed - i.e. it comes on just at the point of take-off and switches off on landing.  The point of having "on" as well is that some procedures require the strobe to be turned on just before entering the active runway and when leaving it.

Hope this helps.

Picture of the panel:


What are the most maintenance-intensive parts of a helicopter?

The question is a bit broad but in general but I will do my best.

First we must look at how maintenance intervals are determined, normally during the initial certification the manufacture testes there aircraft and determines its limitations both in flight, and for maintenance. the regulator generally looks over testing, and documentation and decide if they will approve the 3 parts: the Aircraft, the Flight Manual, and the Maintenance manual. generally the regulator will not do there own tests, they just decide if the testing carried out is sufficient. (this is my best understanding of this, its complicated and a little different depending where/when the aircraft was developed)

Operators who have larger fleets of 1 type of aircraft, or large maintenance/overhaul facility's  will sometimes develop there own maintenance manuals, during these processes they will sometimes demonstrate to the regulator that with newer testing methods etc. that certain components are actually lasting longer than originally proven. Upon approval of there regulator these new documents become law. Occasionally these changes are driven by the manufacture, often when competing for larger contracts ie. Military that wants different maintenance.

As far as "driving" components most people would think the large items requiring very long overhauls, Ie. rotor blades, transmissions and engines.

To answer your questions on shortest maintenance intervals, older helicopters often have small field serviced items such as vibration damping oil struts, or unsealed bering's that may need to be serviced every day or more. Astars air filters need to be cleaned and oiled something like every 15 hours, and piston engines often need oil filters every 25 hours or less. most of these jobs only take an hour or two.

As far as inspections, all helicopters have a daily inspection that is carried out every day checking for issues.


Why do wing tip vortices tend to be most dangerous when there is a light quartering tailwind?

According to the FAA's Pilot and Air Traffic Controller Guide to Wake Turbulence (section 2.4.5) it's because:

Light: in light winds the vortices stay around longer; if the wind is greater than 5 knots then the vortices move out of the way quickly and break up
Quartering: crosswinds blow the vortices across the aircraft's flight path, which means that if you're landing next then one vortex might still be over the runway. With no crosswind at all, the vortices will dissipate on each side of the runway, out of your way.
Tailwind: the vortices are blown in the same direction as the aircraft, which means that the vortices from a landing aircraft will be blown down the runway rather than away from it. Again, that's an issue for the next aircraft landing.

They have a handy diagram to illustrate the vortex paths from an aircraft at 0, 3 and 6 knots. You can see that a light, 3-knot crosswind causes one vortex to still be in the flightpath after 20 seconds, whereas with 0 or 6 knots of wind the vortex is out of the flightpath completely. You can't see tailwind on this diagram, of course, but the principle is the same: it blows the vortex down the runway (flightpath) rather than away from it.


Where are the flap track covers on this wing?

From the Vickers VC-10 repair manual:

General arrangement of VC-10 wing (picture source). Note the labelling of the Shock bodies as "flap rail fairings".

The flap tracks were inside the Küchemann bodies and the flaps were between them. This produced gaps between the five flap segments which made them less effective than the modern design of uninterrupted flaps with the flap tracks below them.


What is this jet aircraft appearing in the 2019 TV Series "Black Summer"?

If this is in fact an actual plane (or a cgi representation of one, it is most likely a F-22 Raptor.
The picture is very blurry and somewhat distorted (probably due to panning), but features fitting to F-22 are:

Trapezoid twin rudders (F-35 has parallelogram shaped rudders)
Rudders fairly far from each other (twin engine)
Rudders canted outwards (rules out F-15)
Relatively high canopy (i.e. F-35 has the canopy positioned much lower in respect to aft fuselage
Sleek fuselage profile (i.e. F-35 has rather chubby fuselage proportions)
Air intake rather forward (rules out F-18)

Not being familiar with the series this is from, I'm willing to bet this is not an actual plane, but cgi. The 3D -model might be totally fictious, only resembling F-22 in the manner described above.


How to find the distance if the points are above Earth's surface?

With the Earth's mean radius being 6,371 km, adding 10 km to that adds about 0.15% to the geometric distance at 10 km altitude. But since you have tagged it flight-planning, the difference is very small that you can neglect.

Since the atmosphere moves with the Earth, TAS ≈ GS in no wind is good enough for the altitudes where planes operate.

However, for a very accurate air distance, use a radius based on the altitude in the haversine formula. But if such high accuracy is needed, you also need to consider the exact Earth's radius at the point of measurement as it varies from 6,353 to 6,384 km. You also need to consider the true altitude as a height above the geodesic, and not just a pressure altitude.


When were the last subsonic turbojet-powered airliners retired from commercial passenger service?

As far as the T-104, Aeroflot retired the Tu-104 from civil service in March 1979 however it wasn't until after the Pushkin crash in February 7th 1981 that killed 52 people that the type was permanently removed from service.

Follow-up / safety actions
The remaining military Tu-104 aircraft were grounded following this accident.

Source: https://aviation-safety.net/database/record.php?id=19810207-0
The last commercial passenger flight of the Comet 4 was by Dan Air on November 9th 1980.

Comet 4s flew with BOAC until 1965 and with British airline Dan Air until 1980.

Source: http://www.bbc.com/future/story/20170404-the-british-airliner-that-changed-the-world
To answer the actual question of the last in service, that appears to be the B707 for all countries.
Trans World Airlines flew the last scheduled 707 flight for passengers by a US carrier on October 30, 1983

An era in U.S. aviation ended at 3:25 p.m. on Oct. 30, when TWA Flight 4, the last Boeing 707 to fly for a scheduled airline in the continental U.S., touched down at New York City's Kennedy International Airport.

Source: http://content.time.com/time/magazine/article/0,9171,952267,00.html
Saha Airlines of Iran was the last airline to keep 707s in scheduled passenger service until April 2013.

All flights of Iranian airline SAHA have been stopped due to its outdated aircrafts. The airline, which has been established by the Air Force of Iran, has operated for 23 years, but the Civil Aviation Organization of Iran stopped its operation due to outdated aircrafts. SAHA owns four planes, including three Boeing 707s with an average age of 36.8 years.

Source: http://www.payvand.com/news/13/apr/1165.html


How do flying wings respond to crosswinds?

Short answer: The reason for crabbing (skewed flight, as you call it) during an approach in crosswind is to keep the wings level while maintaining sideslip-free flight. Flying wings are not fundamentally different, because they, too, have stability characteristics similar to those of conventional aircraft.

Airplanes want to be flown without sideslip. Flying in a sideslip (where a component of the airspeed comes from one side) incurs lots of complications:

Some of the lift is also pointing sideways, so the airplane drifts sideways.
Weathervane stability will make the aircraft yaw into the wind. This comes mainly from the vertical tail, but is only one of many components to make the aircraft controllable.
The dihedral effect will cause a rolling moment, lifting the windward wing.
Wing sweep will increase this rolling moment and add more yawing moment.
Since the vertical tail sits upward of the line of symmetry in most airplanes, this also adds to the rolling moment.

Most of these effects are desired, because they make the aircraft easier to fly, but during approach they make it harder to line it up with the runway. If the fuselage is held parallel to the runway, the windward wing needs to be lowered, so some of the lift points sideways into the wind, compensating the side force caused by sideslipping. This is achieved by keeping the ailerons deflected to work against the aforementioned effects, and the rudder needs to keep the airplane from turning into the wind. This is no problem as long as the airplane is high enough. On touchdown, however, such an attitude cannot be maintained, or the aircraft will hit the ground with a part of the wing or an engine nacelle first.

Only by pointing the fuselage into the wind can the course of the airplane be aligned with the runway in a sideslip-free way. This is called crabbing, because when seen from the ground the aircraft's speed has a lateral component, a little like a crab wich is also known for its sideways movement. Now the wings are level, so the touchdown will happen with the wheels first. Unfortunately, now the wheels' rotation direction is not aligned with the runway, and to reduce wear, pilots kick the rudder just before touching the ground to re-orient the aircraft parallel to the runway.

The Lockheed C-5 and the B-52 can rotate their gear struts, which enables both aircraft to touch down in crabbed flight. All other types produce more tire smoke and jerk the aircraft sideways if they touch down this way.


Mechanical vs Pneumatic Stall Warning Systems

Electromechanical:

Pro - can be tested easily during preflight by turning the mains on and manually actuating the tab

Pro - Potentially lighter (although not my much)

Pro - easy to install multiple switches in parallel if you want to trigger based on a stall of differing characteristics as is done on the Piper Seneca

Pro - Easy to wire into other systems. Maybe you want to add a stick shaker or some kind of feed back to the autopilot, much easier if its already generating an electrical signal.

Pneumatic:

Con - can only be tested by creating a low pressure on the horn, not as easy as the tab option

Many of the above pros become Cons for solid state units, like being harder to connect to other systems with out a transducer, harder to add multiple units without multiple horns, and the weight.


What is that extended nacelle feature on the Honda HA-420 HondaJet?

They aren't covers; they are fairings to integrate the flow going past the lower part of the cowl with the exhaust stream coming out the tailpipe above and the pylon below.  It's because the cowl extends below the engine some distance to house various parts like accessories, plumbing, ducting etc.  You have to create a nice transition for the airflow or you would have a lot of unnecessary drag.

You could say that the fairing is filling in all the 3 dimensional space that the free stream and the exhaust plume can't fill in because the change in direction is too extreme, and would result in flow separation, causing turbulence/drag.


Why does the Piper Malibu require a type rating?

Here in the US the FAA can impose a type rating on any aircraft it likes (see part 3 below). Generally speaking type ratings are either for big planes or planes that may require additional training for safety reasons.
You can find the full regulations relating to US type ratings in the FAR under
§61.31   Type rating requirements, additional training, and authorization requirements.
but basically,

(a) Type ratings required. A person who acts as a pilot in command of any of the following aircraft must hold a type rating for that aircraft:
(1) Large aircraft (except lighter-than-air).
(2) Turbojet-powered airplanes.
(3) Other aircraft specified by the Administrator through aircraft type certificate procedures.

In specific relation to the Malibu the US FAA does not require a type rating, you can find a full list of aircraft that require a type rating here. However it should be noted that to fly Pipers M600 and M500 Malibu variants, both of which have a service ceiling over 25,000Ft you would need a High Altitude Endorsement (along with all the other endorsements for a high performance plane like that).
The JAA may require such a rating due to the pressurization system in the plane.


How should I make a downwind departure from a towered airport?

Typically, you have to think about each phase of flight in three dimensions (sometimes four if you consider time and timing of maneuvers). To be “in the pattern”, you have to be within the patterns lateral boundaries (not the right terminology) and at the proper altitude.

I consider myself to be in the pattern within a mile of the runway and below 1500 feet AGL. At this distance, I can still affect a power-off landing if my engine quits. Although the airport might designate a specific direction for the pattern, I consider either side of the runway as being in the pattern. This is just in case ATC gives instructions to fly counter to the typical pattern, or another pilot does not know the designated direction.

When exiting the pattern, you follow ATC instructions. They even have the prerogative to have you cross over the airfield abeam midfield when you are on the downwind. In the absence of ATC instructions, your best practice is to do one of three things. They are...

Continue straight out on the same course as either the departure leg or the upwind leg. Sidestepping to the upwind leg should get you out of the way of traffic landing on the opposite runway (same pavement). Once you are two or more miles away or above 1500 feet AGL, you can turn to your planned heading. If your desired heading will take you back over the airfield, try to be above 2000 feet AGL.
Once you are past he departure end of the runway, turn in the general direction of the traffic pattern. Keep your turn between zero and ninety degrees while continuing to climb out. Once you are two or more miles away or above 1500 feet AGL, you can turn to your planned heading. If your desired heading will take you back over the airfield, try to be above 2000 feet AGL.
Remain within the lateral track of the airfield during your entire climb to at least 2000 feet AGL. Once you are two or more miles away or above 1500 feet AGL, you can turn to your planned heading. If your desired heading will take you back over the airfield, try to be above 2000 feet AGL.


Did any Boeing 787 operator achieve the 20% fuel efficiency improvement over the 767?

You have not defined your benchmark/reference value, but a three-year-old article suggests this was possible depending on definition even at a very early stage for some airlines:

  ANA earlier this month was the first to reveal that its aircraft were producing around 21% lower fuel burn on international flights compared to the 767-300ER that the 787 is designed to replace.

They also say however:

  After its first six months of service, ANA says the 787 efficiency levels are slightly up on the 20% savings originally expected at the beginning of the program. On domestic routes, the saving is 15-20%, which meets expectations, say ANA officials.


What are the best practices for gathering preflight weather and information?

At least in the US there are plenty of ways to get a flight briefing.
My usual sources of pre-flight information are, roughly in order:

The Weather Channel
No kidding, if I'm planning a long/multi-day trip I'll start looking at the long-range forecasts 10 days before my flight using The Weather Channel's iPhone app or their website.
As far as weather information goes it's pretty decent (which means "frequently wrong up until 24 hours before go-time, but still worth paying attention to").
Charts (VFR or IFR), Airport Diagrams, and the A/FD
If you're planning more than a hop around the local pattern you should familiarize yourself with the airspace you'll be passing through, landmarks (and obstacles) on the ground, and navaid / airport frequencies. Charts and other FAA publications provide a great way to do that, and you can also usually pick up a phone and call the airport you're flying to for additional information.
All of this documentation is available in a variety of forms - Paper, electronic downloads direct from the FAA (as linked above), or as part of flight-planning software like Foreflight, Garmin Pilot, WingX Pro, etc.
The National Weather Service
A few days before a planned flight it's worth reading the forecaster's discussion to see how confident the people predicting the weather are about their guesses. This is also something you should check the day of departure if there's any uncertainty about the weather.
Electronic briefing tools (DUAT/DUATS/Foreflight/etc.)
About 24 hours out you can get official briefings from DUAT/DUATS/Foreflight and a bunch of other flight planning tools. Get them and learn to read them.

  Electronic briefings from many of these tools are recorded and count as an "official briefing" - a record is made that you requested and received the information. You are responsible for understanding all the information that just got dumped in your lap however, and that's a huge responsibility, especially for a student pilot!

Flight Service Briefings (1-800-WX-BRIEF)
The day of departure your final briefing should be a phone call to flight service to speak with an actual briefer to review your flight. If you can sit down and have your electronic briefing from #3 in front of you it's very helpful because you can follow along with the briefer to be sure you didn't miss anything.

  Calls to Flight Service are recorded and count as an official briefing. If you're unclear on anything you're being told you can ask for clarification.

Of all the tools available I personally think the best one is calling flight service and speaking to a briefer. If your instructor has never made you do this I'd say they're skipping out on a critical bit of your training, and you owe it to yourself to pick up the phone and .

This is your big chance to talk to a live human being and ask any questions - big ones that I always ask are "Are there any TFRs along my route of flight?", and if I'm anywhere near a restricted area I'll check its status ("Is R-12345 active?").


Do pilots adjust the aircraft's flight path to allow for the curvature of the Earth?

Aircraft altitude is measured (inferred) by atmospheric pressure. The aircraft is usually flown at an altitude that maintains constant ambient pressure (by pilot or autopilot, as the case may be). Changes in local barometric pressure (provided by air traffic control) are used to recalibrate the aircraft altimeter.  As long as the aircraft is flown at a constant ambient pressure (hence constant altitude), it will be following the earth's curvature (as the atmosphere is attached to the spherical earth and has same properties at same distance from the center, in an ideal case) as the altitude is measured from the surface, which is curved, and not a plane.


Can I use a 150mw green laser to scare pigeons and not interfere with air traffic?

There are cases where you can use a laser pointer safely, such as pointing out constellations in a dark field far from any air traffic, but as a general rule of thumb lasers should not be pointed skyward - not even to get rid of irritating sky rats pigeons.

Should you wind up illuminating an aircraft with your laser you can cause serious problems for the crew - inadvertent or not it could get you a visit from some very unhappy law enforcement officials.

There are many other ways to get rid of pigeons, some of which are used at airports and many of which are more effective (and safer) than your laser idea.
Your local Animal Control group may be able to offer some additional ideas.

(Avoid the "predator bird statue" idea - in my experience pigeons realize it's fake and use it as a toilet.)


Can St. Elmo's Fire cause instruments to fail?

Yes, the strong magnetic fields which are created can cause all of those problems if it gets bad enough.

To quote the AIM where they talk about Precipitation Static (which is one method of creating St. Elmo's Fire):

AIM 7-5-11. Precipitation Static

  b. A review of pilot reports often shows different symptoms with each
  problem that is encountered. The following list of problems is a
  summary of many pilot reports from many different aircraft. Each
  problem was caused by P-static:

  1. Complete loss of VHF communications.

  2. Erroneous magnetic compass readings (30 percent in error).

  3. High pitched squeal on audio.

  4. Motor boat sound on audio.

  5. Loss of all avionics in clouds.

  6. VLF navigation system inoperative most of the time.

  7. Erratic instrument readouts.

  8. Weak transmissions and poor receptivity of radios.

  9. "St. Elmo's Fire" on windshield.

  c. Each of these symptoms is caused by one general problem on the
  airframe. This problem is the inability of the accumulated charge to
  flow easily to the wing tips and tail of the airframe, and properly
  discharge to the airstream.


What do left handed F-16 pilots do about the right side stick?

It does not truly matter what hand the “stick” is in. It matters how you were trained. It matters to what you have become accustomed.

Case in point...
In general, the pilot in command of a side-by-side pilot aircraft sits in the left seat. This is the seat in which most people begin their initial pilot training. You will typically control the control yoke with your left hand while manipulating the throttle, mixture, propeller control, radios and avionics with your right hand. When you advance to being a Certificated Flight Instructor, you will move to the right seat. In the right seat, you will you will control the control yoke with your right hand while your left hand does everything else. If you go on to become a captain in an airline, you will move back to the left seat.

If the same pilot starts training in a helicopter, the pilot in command seat is typically on the right side. You would reverse again which hand controls what.

Your training for the particular aircraft and position you fill will dictate how you operate. Not with which hand you are more dominant. Both right-handed and left-handed pilots fly their respective aircraft the same way. They train for it.


What are the pros and cons of adding a gearbox to larger jet engines?

One major benefit is that gearing slows down the fan
tips below supersonic, giving a major reduction in noise and drag.  The newer massive turbofan jets are ever improving in efficiency, and, with gearing, are taking a page out of the turboprop book to do it.


On an aerofoil or circular cylinder why does the airflow stay attached after passing the point of maximum thickness?

This is due to the Coandă effect.
https://www.britannica.com/technology/fluidics#ref129652

In the 1930s Henri Coandă, a Romanian scientist, described what is now
known as the Coandă effect, a major contribution to fluidic
technology. He observed that as a free jet emerges from a jet nozzle
the stream will tend to follow a nearby curved or inclined surface. It
also “attaches” itself to and flows along this surface if the
curvature or angle of inclination is not too sharp. Coandă explained
this tendency as being caused by the jet stream’s entraining (picking
up) nearby fluid molecules. When the supply of these molecules is
limited by an adjacent surface, a partial vacuum develops between the
jet and the surface. If the pressure on the other side of the jet
remains constant, the partial vacuum, which is a lower pressure
region, will force the jet to bend and attach itself to the wall.


Is there some technology which will help in stall recovery?

On modern airliners we have audible stall warnings (ranging in complexity from a blaring horn to a voice saying "STALL. STALL. STALL."), stick shakers, stick pushers, and in some aircraft sophisticated flight envelope protection systems (control software that simply won't allow the pilot to stall the aircraft).

When everything is working as designed these systems either make it very difficult to stall an aircraft (you would have to ignore the audible warning, ignore the stick shaker, and either override or overpower the stick pusher), or impossible to do so (flight-envelope protection).

When things are not working as designed - e.g. if the pitot (airspeed) and angle-of-attack systems malfunction these protective systems can become ineffective, however in such a scenario any other automated protection system that we would seek to implement would have similar challenges to overcome (if the flight-envelope protection system can't determine that the aircraft is in a stall how would the hypothetical "stall recovery" system know that it should do its thing?)

The idea of airframe parachutes - even a "spin recovery drogue" - for airliners has its own problems and is a largely impractical solution. (I won't rehash the reasons here, but they are well covered in the linked question.)


Is a wind speed of 150 km/h dangerous during a flight in an Airbus A321?

High windspeeds themselves are not a problem, but the environment surrounding them may be.

For example, in the wintertime it is not uncommon to find a strong core of fast winds embedded within the polar jetstream.  We term this windspeed maximum a 'jet streak'.  There are a couple of meteorological phenomena associated around these jetstreaks, such as regions of ascent and descent in the entrance and exit regions of the jetstreak and often times turbulence in the periphery.  You'll also find regions of turbulence on the lateral extent of the jetstream (polar side in particular).  Lastly, if you are flying at an angle to the jetstream or perpendicular to it, you will often experience changing wind direction along with speed, and this can be turbulent.

There is nothing dangerous about that wind speed alone.  What likely happened is that other airplanes were reporting turbulence and the pilots were being cautious with you and just offered that wind speed up as an easily understood number to justify the precaution.


Does the Air Force (United States) help design their own planes?

While the Air Force (or other military unit) does not design their own jets, they do release specifications and have contests (e.g. the ATF that selected the F-22). This is basically the way it works (and not just for fighter procurement):

A design specification is released, these include things like range, mission, weapons.
A "paper" design is submitted from companies like Boeing and Lockheed Martin. These may be based off of existing designs or "clean sheet" designs.
The military funds the development of one or two prototype aircraft from a number of paper designs.
The military evaluates each design against the specification and selects a "winner".
A larger contract is awarded

So it's not really up to companies like Boeing or Lockheed Martin to come up with their own designs and sell that to the military. They work under strict program requirements to develop something "to spec" and then demonstrate the capability. The military has a hand in the design process as this goes along, so they are not entirely "out of the loop".
The secondary market is different though. Boeing may sell (with the approval of the US Government) these aircraft to certain foreign military groups. These work more like selecting something from available stock in the dealer lot.


Why all the taxiway construction at PHL?

From the KPHL website

  Realign Taxiway H and Establish Taxiway EE (North)

  This is the first phase of a multi-phased project to provide a 1,494
  linear-foot extension of Runway 9R-27L, construction of associated
  eastside taxiways and hold pads.  In this phase a new Taxiway EE will
  establish a connection between Taxiways H and K and Taxiway H will be
  realigned between Taxiway EE and the existing Taxiway D.

  Projected completion date: August 2016

As well as,

  9R-27L Extension - Site Prep, Utility, & Fuel Line Relocation

  This is the first phase of a multi-phased project to provide a 1,494
  linear-foot extension of Runway 9R-27L, construction of associated
  eastside taxiways and hold pads.  In this phase a new Taxiway EE will
  establish a connection between Taxiways H and K and Taxiway H will be
  realigned between Taxiway EE and the existing Taxiway D.

  Projected completion date: October 2016

The imagery predates the projected completion dates so it makes sense.


What is this high flying aircraft over Pennsylvania?

Using the location you gave, I tracked back aircraft in that area at that time, and found a scenario that fits with your photo:

(Source: Flightradar24)

So, judging by that, the jet in question is actually a Learjet 31, as said by John K.

Here are some blueprints, and the dimensions are similar:


Can anyone identify this pusher biplane?

It looks like a Farman Aviation Works design but many builders copied the Farman designs.

Most Farman aircraft had straight boxed struts but some had staggered wings and slanted struts:

Maurice Farman biplane

Source: http://flyingmachines.ru/Site2/Crafts/Craft28602.htm#tabs-1

Source:  ebay auction

Also similar to the MF.9

Source:http://flyingmachines.ru/Site2/Crafts/Craft28795.htm


How is the steepness of turn bank properly defined?

I don't know if this is only definition out there, but according to the FAA's Airplane Flying Handbook:

  Shallow turns are those in which the bank (less than approximately
  20°) is so shallow that the inherent lateral stability of the airplane
  is acting to level the wings unless some aileron is applied to
  maintain the bank.

  Medium turns are those resulting from a degree of bank (approximately
  20° to 45°) at which the air- plane remains at a constant bank.

  Steep turns are those resulting from a degree of bank (45° or more) at
  which the “overbanking tendency” of an airplane overcomes stability,
  and the bank increases unless aileron is applied to prevent it.


What constitutes a wind gust in a METAR report?

The definition of "Wind Gust" for METAR reports can be found in the Federal Meteorological Handbook No. 1, chapter 5:

  5.4.4 Wind Gust. The wind speed data for the most recent 10 minutes shall be examined to evaluate the
  occurrence of gusts. Gusts are indicated by rapid fluctuations in wind speed with a variation of 10 knots
  or more between peaks and lulls. The speed of a gust shall be the maximum instantaneous wind speed.


What is the legal situation if a passenger dies in mid-flight?

Unfortunately, having been on board in this situation I can tell you what happened on board my flight:

The deceased was covered and secured in the seat.
The passenger sitting next to the deceased were relocated.

Needless to say, it was a very somber flight. No announcements were made to the effect, but for the people sitting around the rows, it was very sobering.

The aircraft landed and everyone was told to remain in their seats. ER staff along with a bunch of other personnel came onboard.

The body was removed.

Passengers were deplaned.

Years later, I was watching an episode of Ultimate Airport Dubai where an Emirates flight suffers a similar tragedy where a business class passenger is found unconcious.

In addition to the normal scenario on board that I faced, the documentary revealed that:

The crew was changed
The person was pronounced dead by the local authorities


Do anti-collision lights in aircraft lose intensity over time?

No, however the intensity is a feature of the bulb rather than the purpose.

Historically, incandescent bulbs were used, followed by Xenon flashtubes. Currently, LEDs are used in anti-collision lights and other lights on aircraft.

Please note that there are some requirements needed for bulbs used. They are mentioned in 14 CFR 25.1399:

  Show a white light for at least 2 nautical miles at night under clear
  atmospheric conditions.


What are typical naca foils for winglets for ultralights/LSA?

The information I have, is that you would want to have the thinnest symmetrical airfoil, that will work in the specified Re range, eg. NACA009


Why are the B-52 thrust levers advanced inside-out?

Note: Below is valid for applying takeoff thrust (part of the question), but it's now evident it wasn't the takeoff being shown in the video. Refer to OSUZorba's answer.

According to the video description, that B-52 belongs to the 2d Bomb Wing, which operates the B-52H variant.

According to the declassified B-52H manual, the pilot flying should advance all the levers "deliberately and evenly" to the thrust gate. The thrust gate is adjusted prior to takeoff, usually by the copilot, to limit the levers to the set takeoff power setting.

(15) Thrust gate

Initial reference to EPR (Engine Pressure Ratio) is not required. The pilot not flying then adjusts the proper EPR setting for each lever. So the standard procedure is close to what you have in mind.

(Click to view full page)


Why do lavatories in modern planes still have ash trays?

Because in the US (where Boeings are made) it's required by law. 14 CFR 25.853(g) says:

  (g) Regardless of whether smoking is allowed in any other part of the
  airplane, lavatories must have self-contained, removable ashtrays
  located conspicuously on or near the entry side of each lavatory door,
  except that one ashtray may serve more than one lavatory door if the
  ashtray can be seen readily from the cabin side of each lavatory
  served.

The law may be different in other jurisdictions, of course. Why the law still exists is another question, but either no one found the time to change it (laws are often very difficult to change once passed) or it was a deliberate decision to keep requiring ashtrays in case someone tries to smoke anyway.

EDIT: As commenters have noted, the law I quoted requires ashtrays outside the lavatories but it's still common to find them inside. My guess here is that the ones outside comply with the letter of the law, whereas the ones inside comply with the intent, i.e. they're there because if someone does light up, it will be inside the lavatory and not outside in plain view. This 2012 article quotes an anonymous FAA source as saying that people continue to smoke on aircraft so it still makes sense to have them for safety reasons. That raises the question (again) of why the law doesn't fully reflect reality, but that's neither unusual nor unique to aviation.


Can an LLC formed solely to own and operate an aircraft be operated under Part 91?

The short answer is yes, an aircraft owner can hire a pilot to fly him or her, as well as other friends and family, and operate under Part 91.  This is called private carriage, as opposed to common carriage.
Just to clarify a few points:

The pilot hired would need to have a Commercial Pilot Certificate, even if no money changes hands, because the FAA considers flight time as compensation.
The owner could not charge other passengers because this would constitute common carriage, (operating as a charter) and require a Part 135 Operating Certificate.
It makes no difference whether the owner is a rated pilot or not.  Some owners fly themselves, but want the security of having a more experienced pilot along with them.

P.S.  I realized looking related questions on the right side that this is pretty much a duplicate of this question:  Can an aircraft operator hire a Commercial Pilot to fly their aircraft under part 91?


What is the function of a skew sensor in an aircraft?

Skew is essentially when the flap doesn't extend or retract straight back.
Picture a situation where you have a 1 meter wide board you're pushing down a track that's slightly wider than the board.  Your left hand is about a quarter of the way in from the left edge, and your right hand similarly in from the right edge.  As long as you push straight down the track, evenly, with both hands, the board slides along and doesn't contact the edge.  Now suppose that your right hand pushes harder than your left hand: the board will start to turn, and the edges of the board will contact the edges of the track.
The skew sensor detects that this sort of misalignment is starting to happen, and causes the flap drive to stop.  Ideally, this takes place before the flap makes physical contact with any other hardware, so nothing is damaged!
Edit:
Video of flaps being extended & retracted on the ground.  You can see that there are multiple flaps on each wing, and while normally everything moves in synch, you can envision how if one actuator stopped working, the errant flap could get turned pretty far out of alignment, make contact with other hardware, and cause some significant damage.  So before this happens, the skew sensor sends the command back to stop everything from moving.
From Boeing's Aero Magazine:

The 757-300 has incorporated a flap skew detection system. Flap skew occurs when either the inboard or outboard edge of the flap moves farther than the rest of the flap. The flap skew detection system monitors, detects, and shuts down the flaps if a skew condition occurs. The heart of this system is the flap slat accessory module (FSAM), taking the place of the flap slat electronic unit (FSEU) number 3. The new LRU was introduced because the existing configuration of the FSEU would not accommodate the addition of the flap skew circuits.
The flap skew sensors are mounted on the trailing edge of the flap jack screws (fig. 4a). The sensor (fig. 4b) is fixed to the flap track, and a target (which contains magnets) is mounted to the jackscrews. As the jackscrew begins to turn, the target also turns. This will pulse the sensor, and a signal (distance traveled) is sent to the FSAM, which compares this signal with the opposite side of the same flap. If the distances traveled by either side of the flap differ by a predetermined amount, the FSAM will shut down the flap system to help eliminate damage to the flap and surrounding structure and the possible loss of a flap in flight. The alternate flap mode will override the normal flap skew detection function, allowing maintenance personnel to move the flaps after maintenance has been performed. Maintenance personnel must verify the flap fault and also ensure that moving the flap will not cause any damage.