Can a helicopter have a fully mechanic "elevator"?

Using a building elevator would cut the payload of the helicopter in an unacceptable way. Also, none of the safety features of a building elevator could be implemented, and in the end you will have a cage lowered on a rope. Which is quite similar to existing winch systems.

Elevator components (source)

In addition to the motor and the pulleys, a building elevator has a car which runs along guide rails, and a counterweight to compensate for the heavy car. Adding all this to a helicopter would require a much bigger machine just for carrying the elevator components around. Note that using guide rails would dictate a specific hover height - no helicopter pilot would agree to have his options restricted that severely.

Lowering anything in the downwash of a helicopter rotor will cause it to swing and rotate, and putting the occupants into a cage will cut their ability to stabilize themselves or the cage. Once the cage is raised all the way up, it needs to be oriented correctly for easy egress. A rescuer on a rope can easily stabilize himself by grabbing handles on the outside of the helicopter. Sitting in a cage, he can only watch helplessly when the cage arrives in the wrong orientation.

There are many scenarios where rescue helicopters cannot land, like over water or over a forest. In those situations a winch is used to hoist one rescuer down to the ground, where he/she can pick up the injured and secure them to their harness. Both of them are then raised up and taken on board. Only when the patient must not move (think fractured leg), a platform is used to secure the patient. See below for a simulator installation, and note that still a rescuer is needed to stabilize the platform.

Helicopter rescue hoist trainer (source)

If the ground allows, landing the helicopter is simpler, makes much less noise and makes it immune to changing winds. Also, lowering the rescuer first and landing the helicopter will take a similar amount of time, so no substantial time savings can be expected.

AgustaWestland AW139 helicopter on SAR exercise (source)


Is right rudder always needed during go-around/touch and go with a Diamond DA-40?

"More right rudder" is like a Flight Instructor's mantra, for most all small single engine planes where the propellor spins clockwise from the pilot's viewpoint, and right rudder is needed when engine power is suddenly increased to counter the engine torque and airflow effects.


What prevents the use of an EMAS along the sides of a runway?

I can think of a couple reasons why you might not want to expand EMAS all around the edges of the runway.  One is simply cost vs benefit:  If it is more likely that an airplane will run off the end of the runway than the edges it would make more sense to put the material there.

EMAS would seem most beneficial in stopping forward speed if the wheels were to make contact uniformly.  An aircraft departing the side of the runway already has directional control problems.  The situation would be amplified if the wheel on the side “pulling” the aircraft off the edge was to be dramatically decelerated.  It could even cause a ground loop.


What happened to this airplane at Lombok Airport?

(Source)

The aircraft's registration is PK-YVL. It's a Boeing 737-300 that was operated by Batavia Air before the airline ceased operations.

This plane is/was leased from Pacific AirFinance. It has been withdrawn from use and stored at LOP since 31 Jan 2013. After ceasing operation, some of the other 737-300's the airline had were delivered to Peruvian Airlines.

Due to its proximity to parked aircraft, it's not likely the plane has been converted to train firefighters. The darkened area could just be storm blown mud.

(Source) Same plane, previous operator.


Could a tilt quadcopter use turbofan engines?

In a way, this has been done already half a century ago.

When NATO decided to try a VTOL strategy, the Harrier was not the only result. There was even a supersonic VTOL fighter, and it used swivelling engine pods at its wingtips, much like the V-22 does today. It was the VJ-101C, developed in Germany and first flown in 1963.

VJ-101C in flight. Note the opened intake door aft of the cockpit where two additional lift engines were complementing the thrust from the wingtip engines (picture source)

While the VJ-101C used six Rolls-Royce RB145 turbojets, a later production version was planned to use turbofan engines. NATO changed it's mind before the turbofan-powered version was built, however.


Why is the N-number on the tail of aircraft sometimes shown in both large and small font?

The N-Number marking regulations are outlined in this AC for fixed wing aircraft:

  ... minimum height of 12 inches

  (1) On both surfaces of a single vertical tail or on the outer
  surfaces of a multi-vertical tail, or

  (2) On the fuselage surfaces, on
  both sides of the fuselage between the trailing edge of the wing and
  the leading edge of the horizontal stabilizer. If engine pods or other
  equipment are located in this area and are an integral part of the
  fuselage side surfaces, you may place the marks on those pods or
  equipment.

However for some time 2 inch markings were allowed:

  On an aircraft displaying 2-inch marks before November 1, 1981, and on
  aircraft manufactured between November 2, 1981, and January 1, 1983,
  you may display those marks until the aircraft is repainted or the
  marks are repainted, restored, or changed. Once the aircraft is
  repainted or the marks are repainted, restored, or changed, the
  N-number is required to be 12 inches high.

Its possible the numbers you are seeing are the old ones and the new 12 inch numbers were applied directly beneath it to comply with the new marking regulations while the old ones were simply not removed.


Disadvantages of using thrust vectoring only in an aircraft with variable rotation nacelles such as the X-19

It is my belief is it would allow the use of highly complex airfoil geometries that would increase the efficiency of the aircraft.

The best airfoil is one that adaptively changes shape to meet current requirements (read: flaps or flaperons that run the entire length of the wing).

  What would be the advantages of using thrust vectoring only for control of roll, pitch and yaw?

That's how the V-22 works. During horizontal short field takeoffs, the engines are angled forward and upward and the flaps are fully deflected to generate maximum lift. Pitch and roll control are provided by thrust vectoring and differential thrust (the V-22 has conventional swashplates). Below is an image of a V-22 during takeoff. (source)


What are the factors considered while placing a propeller on a plane?

The biggest factor is familiarity: What has worked before?

Other factors are:

Propeller size: Slow-turning propellers driven by powerful engines have a big diameter. This is desirable because it improves efficiency. However, now the propeller cannot be placed behind the wheels if the rotation angle should not be restricted.
Engine location: Driveshafts cost weight and run the risk of resonance problems, so the propeller should be directly in front or at the back of the engine. The engine location is dictated by the desired mass distribution, cooling, the pilot's field of vision, and space demands.
Interference: This includes all factors like prop wash and swirl. Putting the propeller ahead of control surfaces or flaps improves their effectiveness at low speed. Conversely, the increased flow speed increases friction drag on the surfaces wetted by the propeller's slipstream.
Stability: The propeller acts like an additional small wing and creates lift and side force when not exactly perpendicular to the inflowing air.
Engine-out performance: Multi-engined aircraft should still be flyable with one dead engine. This is an interaction between propeller location and control surfaces, and to minimize drag, those control surfaces should be as small as possible. Thus, the propeller should be close to the center of gravity.

The rear propeller is more efficient, because it helps to prevent separation on the surfaces ahead of it, and its slipstream will not increase the friction drag. However, integrating a propeller at the back of an aircraft is hard, so few designs (apart from those in this answer) made use of it. Notable examples are:

A range of British fighters during the early years of WW I, when only the Germans had mastered the technology of synchronized machine guns.
The Zeppelin airships. Their gondolas had rear-mounted propellers.
The Convair B-36. The pusher location in the wing was selected for better efficiency, but created cooling problems for the engines.
The Learfan, started during the first oil shock and designed for efficiency. Two PT-6 drove a single pusher propeller.
The Piaggio P-180 Avanti, which was designed a few years later and much for the same reason as the Learfan.

Also, Claude Dornier had used two engines in one engine pod, driving a propeller each at the front and at the back, as early as 1915, when he worked for Zeppelin on a giant metal flying boat. This became a common theme on many Dornier aircraft, especially the flying boats, and on the Zeppelin Staaken giant bombers. The last example of this range is the Dornier Seastar, designed in the late 1970s.


Is there a symbols chart or legend for common aerospace equations?

Unfortunately, the nomenclature used can vary from source to source, and the same variables can even be used for completely different things depending on the context. It is generally good practice for the author to describe the variables they use, but we've all been guilty of skipping that step.

In any case, there are many helpful sites such as See How It Flies or the Aerodynamics Index from NASA that tend to use pretty 'standard' notation. BUT, there is no single cheat sheet that has every variable for every analysis and one should always be careful to double check.


When are ATC frequencies preset in the radios?

I'm not aware of any rules, hopefully others can contribute, but you can usually predict the next frequency with a high rate of precision.

For example (exact stations will differ depending on airport and airspace type) a typical IFR sequence of stations.

Clearance delivery
Ground
Tower
Departures
Sector/area
...
Sector/area
Approach
Tower
Ground

The initial tuning will put delivery in live and ground in standby.  Then as you say, just press the toggle.  When the next frequency gets dialled in is not, as far as I know, governed in anyway and is probably not even in SOPs since it is just about using the equipment more efficiently.

Say delivery has given you a clearance.  They will probably follow up with something like "call ground 129.7" for push and start".  When you are ready for push and start, toggle to ground then put the tower into the standby frequency and so on.

Frequency changes are certainly made in cruise, when passing from one ACC sector to the next. These frequencies are published in the national AIP's and visible on en-route charts.  For a sector handoff, I'd probably dial the next frequency in when the current sector instructs me to contact xyz.

It's really not a big deal if you have to contact someone unexpected.  Modern boxes with push button tuning are almost as quick to tune manually as to toggle.


How long is a METAR valid for after issuance?

A METAR is a report of conditions at a specific time, so it's only valid when it's issued. It's not a forecast, the weather could be different 5 minutes later. TAFs are forecasts that have a time range, they are valid during that time range. That doesn't mean they are guaranteed to be correct, it's just a prediction.


If propeller-driven planes with electric engine became the norm, would descent for landing with the engines turned off become a routine procedure?

It's unlikely the pilot would be switching the "propulsion master" off, but it's very probable that "idle power" on the throttle or thrust lever would in fact be a stopped or stopped/feathered motor.  It's likely that regen braking would be electrically available, but it's probably something you wouldn't want to use in flight, for the same reasons you don't engage reverse thrust on jet engines before touchdown (in fact, there are some aircraft where you do, for a subset of the engines, in part because of the time needed to engage reversers).

Having instant throttle response available is very important, so "off" shouldn't be the same "off" you'd use when parking and tying down -- but having genuinely zero thrust could be useful for certain kinds of approaches (others, you want/need to carry some power to ensure you stay enough above stall to maneuver without steepening the glide slope).


Is there any recorded instance of a passenger's hat or scarf being blown into an aircraft's engine?

If you are boarding with an engine running, it's going to be the one on the opposite side running with the one on the boarding side shut down.  However, there's little doubt that items like that have flown off heads in high winds and drifted across to the opposite engine and been ingested, in all the millions and millions of flight hours over the decades.

In any case, something light enough to get carried off by the wind like that would just pass through the fan, or, if it was sucked into the core, get chopped to little pieces, burned and come out the back as ash particles.  A large enough item would probably cause enough flow disruption to affect the engine's idle and give a turbine temperature spike, but it's unlikely to do significant damage unless it was, say, an entire coat or something, and that would required a mighty windy day.

What's biggest Foreign Object Damage threat to engines on the ramp?  Luggage zipper tags.


Basic Math:

How long will the plane be in the air?

$\frac{9842.52 ft\ \text{AGL}}{800\ fpm} = 12\ \text{minutes}$

How far will the plane go in 12 minutes?
$68kts \cdot \frac{12\ minutes}{60\ min/hr} = 13\ \text{NM}$

Assumptions

Assuming no tail wind or head wind, so that KIAS relates to actual ground-speed.
Approximating that 68 KIAS is the ground-speed, when it is in fact the slant-distance speed.   If you need a precise answer, apply the Pythagorean Theorem to refine the answer.


Are the replacement satellites for Iridium going to provide surveillance coverage?

The next generation of Iridium satellites will have ADS-B receivers installed on them which will be used to track properly equipped aircraft. The company providing this service is Aireon.

Most airliners are already equipped with ADS-B transmitters. From 2020 it is manadatory on the USA and in Europe to have ADS-B.

The first satellite were to be launched earlier this year, but so far nothing has been launched.


Why would a flight no longer considered airworthy be redirected like this?

There could be a lot of reasons for this...

EU closed airspace to 737's MAX 8's on March 12
They needed to go into a holding pattern until ATC figured out where to put them
They needed to be in the holding pattern until they could get a landing slot
They were redirected to an airport that had a maintenance facility that the airline uses
They redirected to an airport with code-share partners so they could rebook passengers without a major fee

Edit I'm not sure what is going on with FlightRadar24, but it shows that the plane continued to Prague the next day. It looks like they landed in Ankara then continued on to Prague. I'm not sure if the flight to Prague was just a repositioning flight, or if it had passengers.

Edit 2 Turkey subsequently (after this flight) also closed airspace to 737 MAX 8's. The EU closure allows for ferry flights, which are flights without passengers on board. The flight from Ankara to Prague was just a positioning flight so that the aircraft could be serviced when it came time to implement a fix from Boeing.


Should "Thrust Reduction" and "Acceleration" heights be the same for the Boeing 737 NG?

In absence of any other constraints, both thrust reduction and acceleration should be initiated at 1000 feet above aerodrome elevation:

Flap Retraction Schedule
During training flights, 1,000 feet AFE is normally used as the acceleration height
to initiate thrust reduction and flap retraction. For noise abatement considerations
during line operations, thrust reduction typically occurs at approximately 1,500
feet AFE and acceleration typically occurs between 1,500 and 3,000 feet AFE, or
as specified by individual airport noise abatement procedures.

(Boeing 737 NG FCTM 3.32 - Takeoff and Initial Climb)
Regarding your thought of

I always thought one does not reduce thrust before cleaning up but reading some posts I am in doubt now.

It is actually quite normal to reduce thrust before accelerating and retracting flaps. During NADP 1 (Noise Abatement Departure Procedure), which is most common around the world, thrust is reduced first (typically between 800 and 1500 feet) and acceleration is initiated later (typically at 3000 feet). For NADP 2 both occur at the same time. I don't know any procedure where thrust reduction occurs after acceleration.

Both heights can be set independently on the TAKEOFF REF page 2:

Thrust Reduction (THR REDUCTION)
Altitude above origin airport elevation at which the autothrottle reduces from
takeoff N1 to climb N1.
The default value is determined by the airline and is stored in the model/engine
database. The default is displayed in small font.
Manual entries allowed on the ground. Entries must be between 800 to 9,999 feet
and are displayed in large font.
Acceleration Height (ACCEL HT)
Displays acceleration hight for flap retraction.
Default value is from the airline.
Entry is optional. Value is a height from 400 to 9999 feet.

(Boeing 737 NG FCOMv2 11.40 - Flight Management, Navigation - FMC Preflight)


How do STOVL and V/STOL aircraft differ?

To put it simply, it's about the ability to take of vertically at any mass:

V/STOL aircraft can take off fully loaded (max. operational weight).

STOVL aircraft does not have sufficient engine thrust to take off vertically at any weight, and at higher T/O weights it must have some lift from wings to assist the T/O. It may be able take off vertically at less than max. T/O weight.


For slow-flying ultralights, how would a delta wing compare to a biplane layout of equal wing area?

One major issue with a delta wing was discovered in the early days of supersonic fighters: delta wings don't handle well at low speeds.  At high angle of attack, they (like any highly swept planform) exhibit strong "Dutch roll" in which roll and yaw are coupled in an oscillation, and because they stall at very high angles of attack the Dutch roll comes on when control authority is at its lowest.

Your plan, to fly just above the stall at very light wing loading, will require control surfaces that make up a very large percentage of the total wing area, effectively compromising lifting area.  You'll also need a very large vertical fin to maintain stability, and much/most of that will need to be movable for yaw control.

Generally, the main reason Rogallo-derived designs have maintained dominance in hang gliders is because they overcome most of these failings of rigid deltas, and can be made lighter, store more compactly, and cost less to construct as well.


Why are passenger required to put their phones in Airplane Mode during taxi to gate?

In general, they don't. U.S. airlines generally allow you to use your phones as soon as the plane lands.
Southwest:

Effective today, Southwest Customers with cell phones onboard may begin using them after the flight attendant gives permission to do so upon landing at the destination and taxi to the airport gate.

Source: Southwest Press Release from Sept 2, 2003
Delta:

Use of cellular devices prior to takeoff is not allowed per Delta policy so that flight attendants may properly prepare the cabin for departure and conduct safety demonstrations uninterrupted. Cellular devices may be used upon landing as instructed by the cabin crew.

Source: Everything You Need to Know About Using Devices on U.S. Airlines

Perhaps of interest, the rule against using cell phone during flight in the U.S. is not an FAA Federal Aviation Regulation. It is instead an FCC (Federal Communications Commission) regulation designed to prevent interference to the cell network as a result of thousands of phones flying around at 600 mph hitting hundreds of cell stations at once. In general, the FCC acknowledges that this rule is outdated and that this is no longer an issue for the current cell network. As such, the FCC has issued a proposal to remove this regulation. However, some airlines (including Delta and Southwest) have publicly stated that they will continue to not allow cell phone use for voice calls during flight even if it is legal, as the majority of their customers have indicated that they don't want to listen to their neighbors chatting on a cell phone for hours on end.

Delta will not allow cellular calls or internet-based voice communications onboard Delta or Delta Connection flights. Our customer research and direct feedback tell us that our frequent flyers believe voice calls in the cabin would be a disruption to the travel experience.
In fact, a clear majority of customers who responded to a 2012 survey said they felt the ability to make voice calls onboard would detract from – not enhance – their experience. Delta employees, particularly our in-flight crews, have told us definitively that they are not in favor of voice calls onboard.
-Delta CEO Richard Anderson


Why is the flight going north just to go south?

Aside from the storms causing an earlier re-routing, that jog north is to join the arrival into EWR.  A common fix in NE Ohio on flight plans into EWR is the DJB VOR which is in Loarine county (I think, somewhat near Cleveland). and then routing over Slate Run and then Williamsport, PA on the way into Newark.  If you are a jet coming from the west, this is literally the only way into EWR.  The other two ways in are from the south joining somewhere on a line between Atlanta and Baltimore (which you can transition to from the west by going over Beckley, WV) or from the north coming in over Albany, NY.  The primary reason for the strict routing starting at around the OH/PA border is the need for multiple arrival descents for both jets and turboprops into the various NY area airports (EWR, JFK, LGA, TEB, etc), the westbound departures out of NY center and the letters of agreement between Cleveland and NY centers to manage these traffic flows.

See this image:

This represents a route of ..J29.DORET.J584.SLT.FQM3.  This is not the exact route a LAX originating flight would normally get as they would end up a bit further north (going over Detroit instead of Cleveland), but they would still converge on J584.SLT.FQM3 (the portion east of the OH/PA border).  No matter your position west of the OH/PA border, Cleveland center is going find a way to put you on J584 before you get very far into PA.  This is why the flight couldn't just go direct to EWR and had to first fly north.


What is that term to describe the wing motion range?

The term that you are looking for is Wing Flex. The extent of flex is a product of the material.The wing needs a stated definitive strength. With metal, that transforms into a given amount of flex. IOW, the flex, is basically just a by-product of the materials and high aspect ratio design and is not a design goal in itself. The benefit is, smooth ride during a turbulence.

Aerodynamically you do pay a penalty. However, to a certain extent this will be offset by lighter weight and the much superior strength, facilitates the high aspect ratio which more than make up for the loss due to the flex.


What type of variation in temperature does the wing undergo?

The temperature rise that is caused by flying at high subsonic/transonic speeds is approximately 40 degrees Celsius. But this happens only at the stagnation point (near the leading edge). Ref: aerodynamics text books.

The A380 and other airliners experience -55 to -60 degrees Celsius during cruise at altitude. Ref: aerodynamics (properties of the atmosphere)

On the ground they may experience up to 60 degrees Celsius of air temperature and with the sun radiation the surface temperature can rise up to approx. 80-90 °C. Depending on color and geographic location on earth. Ref: hard experience :) and Environment control system Analysis.


What's the right way to take a dog in a small plane?

My wife and I have a small dog that frequently travels with us.  We place her in a soft-sided kennel that straps onto the seat belt.  While this doesn't do anything to help in a sudden impact (i.e. crash), it does help to keep her from being bumped around in case of turbulence.  For larger dogs, I know that there are seat belt tethers out there.  My suggestion would be to strap them to a rear seat.  In either case, the big issue is to ensure they don't get in the way while operating the aircraft.

As for the hearing part, a company called Safe and Sound Pets makes a product called Mutt Muffs.  Their website is here.  My wife and I bought a pair, but our dog wouldn't have anything to do with them and they were returned.  Of course, your dog may be better behaved :D


Should an IFR-certified radio's automated nav aid identification feature be considered positive identification?

This question has been discussed a couple of times on the AOPA forums (members only) and the conclusion there was that it's completely fine to trust the automated identification. If the system is fully certified for IFR then why wouldn't you trust it? And if you don't trust one specific feature then why should you trust any of them?

Identifying NAVAIDs correctly is in the instrument PTS but the FAA doesn't require any specific method of checking. In my last instrument checkride I used a G1000 and the DPE had no problem with me using the automatic identification; that's what it's there for.

Having said all that, things can and do go wrong, so cross-checking against other sources is still a good idea. For example, when you load a VOR approach from the database, the G1000 will automatically tune NAV1 to the NAVAID frequency and identify it. If either the frequency or the name doesn't match what's on the approach plate - or if the name is missing because it couldn't be identified - then something is wrong and you need to investigate.

Ultimately I think this is a question of comfort level, both personally and with the equipment. Some people will check the morse ID directly every time, out of habit or preference. Others won't, because they're confident that they know the equipment well enough not only to trust it, but also to identify and handle any problems.


Why wasn't there a belly gunner on the B-25 Mitchell?

The production B-25B, B-25C, B-25D, and some B-25G models did have retractable remote control belly turrets. They were often removed in the field because they were ineffective and disliked by the crews.

The lower turret was officially deleted in the middle of the B-25G production run and continued with the B-25H and B-25J production.

More info on the B-25 here: B-25 History.org


If no low-speed compromises were made, what would an ideal Mach-3 wing look like?

One Mach 3 design which did not care about low speed characteristics was the Lockheed Q-12 / D-21 reconnaissance drone, which used a Marquardt RJ-43 ram jet for propulsion and had a flight Mach number of up to 3.5. It was initially air launched from the back of an A-12 / M-21 and crashed when fuel ran out. The purpose was deep penetration of hostile airspace to perform photographic reconnaissance in pre-satellite days. When later the launch aircraft was switched to the B-52, the D-21 needed an enormous booster to bring it up to its cruising speed of Mach 3.35.
This should be closest to a uncompromising Mach 3+ design; however, it drew massively on the aerodynamic work with the A-12 / SR-71, so probably the solution space was restricted from the start.

D-21 three side view (picture source). The anhedral was needed to compensate for the rolling moment of the high tail in sideslip. An even more uncompromising design would had used a smaller vertical and an equal fin on the lower side and no anhedral. The lower side fin, however, would have made the air launch from the back of the A-12 impossible.
All surfaces had sharp trailing edges. A wedge-like cross section like the tail of the X-15 only starts to make sense at speeds in excess of Mach 5 when using drag for directional stability is more effective than adding more tail surface.


How do pilots rest on long-haul flights?

Since a picture speaks for a thousand words...

These are often called "coffins" or "sarcophagus" around here... (Portugal)

Source


Is there a European equivalent of VFR Flight Following?

Yes, it is called Flight Information Service (FIS). FIS is defined by ICAO, and the term is used in most of the world. "Flight following" is a local term used only in certain countries.

A flight information service (FIS) is a form of air traffic service which is available to any aircraft within a flight information region (FIR), as agreed internationally by ICAO.
It is defined as information pertinent to the safe and efficient conduct of flight, and includes information on other potentially conflicting traffic, possibly derived from radar, but stopping short of providing positive separation from that traffic.
Flight Information also includes:

Meteorological information
Information on aerodromes
Information on possible hazards to flight

FIS shall be provided to all aircraft which are provided with any air traffic controller (ATC) service or are otherwise known to air traffic service units. All air traffic service units will provide an FIS to any aircraft, in addition to their other tasks.


What is the average speed used by modern jet fighters when in dogfight?

Modern Air Combat Maneuvering takes place between about 350 to 600 KIAS; There is no specific speed but each aircraft has a specific optimal cornering velocity which gives it the greatest rate of turn in order to maximize its maneuverability.  Pilots will seek to maintain this speed when entering a merge as it can give them the greatest maneuvering advantage in order to turn inside on opponent or for jinking to evade a cannon or a missile shot.  As an example, the Lockheed Martin Block 50/52 F-16C has a cornering velocity of 420 KIAS.

Traditionally air combat has been about energy management.  Fighter pilots have something in common with economists in that they are engaged in the art of managing the flow of currency; in the case of the pilot that currency is energy and not money.  The total energy state of a fighter is:

current energy state = energy in - energy out.

The current energy state is the sum of the kinetic energy, proportional to the square of the velocity of the jet and the potential energy of the jet, which is proportional to its height above the ground.  Energy leaves the system in the form of parasite and induced drag acting over a distance as well as loss of altitude, which is proportional to the flat plate area of the jet, load factor, AoA, etc.  Energy enters the system at a rate proportional to the amount of jet fuel burned; this supply is limited to the fuel onboard which again affects the mass of the jet, the induced drag, etc.

So keeping this in mind, a good fighter pilot will seek a way in which he/she can maneuver through space, gaining the best speed and turning performance for the least amount of energy consumed, in order to land in an advantageous position to employ the weapons against an enemy jet.  These kinds of speeds vary between if the jet is on the offensive or defensive in relation to a threat.

So a pilot maintaining that optimal energy state is in the best position to attack, or defend against an attack, and a pilot in a very low energy state is very vulnerable - "low and slow, you're outta dough" - and could be quickly killed in a multi-jet furball.

The cornering velocity is preferred for this reason if maneuvering is anticipated (a given if the jet is about to enter a merge).

With the advent of terminal homing, beyond visual range missiles allowing pilots to stand off from the fight and shoot a threat before it could get close enough to turn with them, higher speed cruise, along with a capability to maneuver well at those higher speeds has become an advantage.  It allows a pilot to more quickly close with an enemy aircraft into the missile's 'no escape' zone, fire, and then turn and dash from the threat, minimizing their presence in an enemy's 'no escape' zone whereby enemy missiles simple don't have the available energy to catch you.  This was the basis for supercruise - supersonic cruise without the use of afterbruners - on the ATF / F-22 program.  Combined with good frontal stealth to minimize the detection range by enemy fighters, supercruise could give a Raptor jock a major advantage in the BVR areana - near invincibility in BVR engagements against non stealthy fighters, if the published results of the Red Flag and other military exercises are to be believed.


Do special procedures exist for commercial pilots flying over Russia?

Does Russia provide radar coverage and flight following services over its entire territory?

Not all countries publish the exact radar coverage, as it is sensitive information. But, if the flight over Russia is IFR (controlled), then the answer is yes, regardless of the remoteness of the area.
The services and limitations can be found in any country's AIP, and the Russian AIP is publicly available. By checking GEN 3.3:

1.3 Radar service is provided at all phases of control service indicated in para 1.2.

and 1.2 basically covers all phases of controlled flight:

1.2 The air traffic control service is divided into:
a) area control service - the provision of control service for flights of all aircraft in CTA (FIR/СТА), except those indicated below in items b) and c);
b) approach control service - the provision of control service connected with arrival and departure of all aircraft;
c) aerodrome control service - the provision of control service to aerodrome traffic, except that indicated in item b).


Why are jet engine nacelles, used on the same plane, so different?

Sometimes manufacturers will certify with multiple engine types because their customers have their own power plant preferences (or manufacturer preferences, like say an airline's existing fleet is RR engines and they want to keep engine commonality for logistics benefits, or an airline feels one model engine is cheaper to run than another).  Providing different powerplant options for an airliner can therefore result in more sales.


I want to be a French fighter pilot. Any advice?

The third point in your original list is a clear red flag:

  I'm a huge fan of airplane (but I'm not the type of guy loving learning every thing by heart)

I don't mean to put you off with what follows, but honestly, you've got to love learning everything by heart in the military in general, let alone the airforce.

Becoming a professional pilot is demanding, becoming a military pilot even more so. Both require high intellect, the ability to learn and memorize things easily and preferrably, especially in military aviation, a burning desire to do so.

On top of that, to make it as a military aviator, not only do you have to be enthusiastic about aviation in general, but you have to have just the right mindset: utmost dedication for the military way of life, deep patriotism, and absolute altruism. Any succesful military person is first and foremost a soldier, only in addition to that can one be something more.

The guys and gals at military aviation operate on a whole different level from an average pilot. You simply are not going to make it if you are not all in. About aviation and more importantly about military.


Can a C152 land VFR in Miami International Airport (KMIA)?

Sure can if your C-152 is equipped with at least a two way VHF radio and a transponder with altitude reporting capability.  And you hold at least a PPL with current medical or are a student pilot with current medical and have a logbook endorsement from a CFI to fly there.

According to the A/FD entry for KMIA, all GA arrivals should file request a clearance at least three hours in advance of their arrival.

As with flying into any Class B airport, you will have to be on top of your game and able to quickly and accurately comply with ATC instructions.  Have all you charts and plates ready to go, especially taxi diagrams and frequencies.  Expect taxiing delays and instructions.  Wake Turbulence avoidance procedures should be used and anticipated.


How do I determine the center of gravity on aircraft?

You ask particularly about the Center of Gravity (CG), but not the weight. Any CG calculation will necessarily include the weight as a component of the calculation; therefore I refer to the calculations as weight and balance (or CG) calculations.

The two primary ways that weight and balance measurements are determined are by physically weighing the aircraft and by mathematically calculating based on additions or subtractions to the previous weight. The former is performed by maintenance personnel and forms the empty weight and CG for any given aircraft. The later may be performed by either flight operators or by maintenance and uses the predetermined empty weight and CG as the basis for the calculations; this may be needed due to the installation of new equipment, for example, or a pilot may do such a calculation to determine the weight and CG for a given flight with, for example, fuel and passengers.

For maintenance operations, most aircraft have a section in the maintenance manual or operating handbook that prescribes the process. For flight operations, most aircraft have an information manual or operating handbook that will prescribe the calculation.

One necessary parameter is an established reference datum.

The basic formula is:

$$
C_G=\frac{(W_1\cdot A_1)+(W_2\cdot A_2)}{W_1+W_2}
$$

Where:

$W_n$ is the weight of the aircraft scale's measurement, predetermined empty weight, fuel, or payload, etc.
$A_n$ is the moment arm, in reference to the datum, of the of the aircraft scale's measurement, predetermined empty CG, fuel, or payload, etc.
$C_G$ is the solution to the center of gravity for the aircraft.

The cancelled FAA Advisory Circular AC65-9A contains an entire chapter (Chapter 3) dedicated to the subject of weight and balance, including exactly what you ask, the parameters that must be considered and the formulae used to perform the calculations. Though cancelled, the AC is still available online (I have a print copy).

EDIT: See the comment below from @voretaq7 referencing the excellent "Aircraft Weight & Balance Handbook" quoted here:

  In addition to AC 65-9A the current Aircraft Weight & Balance Handbook
  (FAA-H-8083-1A - available here) contains more than you ever wanted to
  know about computing weight & balance.

This is currently the direct link to the PDF of that document.


With regards to John's comment, we should remember the other player applying torque to the Center of Gravity, the horizontal stabilizer/ elevator/ stabilator/ trim tab.  Ideally both the thrust line and the horizontal stabilizer will be 0 degrees to the horizon with the wing at optimal cruise AOA.
Under power, relaxing static stability with a little competing downthrust will lessen the need for excessive trimming any time thrust is changed, and also leaves static stability full on when the plane powers down to land.
This is a very safe and widely used application of downthrust for GA aircraft.  Because the cosine of the small downthrust angle is very small (cos 3 degrees = 0.9986), effect on the horizontal thrust component is minimal.


How do pilots manage the speed during the approach?

The Boeing chart you reference appears to use for the approach speed column the Vref speed of the aircraft at its max landing weight in the landing configuration. This is the speed you want to be at or close to when you start the landing flare (the two 747 carriers I flew for used Vref+5).

Absent charted speed limits, controller instructions, or company policy, there is no specific distance threshold along the approach path that you cannot cross above that speed. The requirement is to be at the proper speed when you enter the landing flare.

However, if you were, say, flying the classic stabilized approach, you would be in the landing configuration at this speed from the FAF (final approach fix) to the landing flare. The FAF is typically around 5 miles from the runway.

Now, insofar as speed stages, the requirement is not one of specific distance points along your approach path (again absent charted limits, etc.), but rather what you have to do speed wise while changing from a clean configuration to the landing configuration. You're approaching the airport with the gear and flaps up. The critical element speed wise on the approach is the wing configuration.

Given the 747-200 speed of 150 kts in that chart, if you slow to that speed with the flaps up, you will stall. The minimum safe speed would be around 80 kts greater than that. Go to flaps 1 (which really doesn't put the trailing edge flaps at 1 degree but rather puts out the leading edge flaps or slats as some call them). Once they're out you can safely slow to Vref+60. At flaps 5 you can slow to Vref+40. At flaps 25 you'll be able to safely slow to the Vref speed in normal operating conditions.

Other aircraft have different flap settings and different speeds. The important thing to remember is that you're changing the shape of the wing to be able to fly more slowly. Where you will be along your approach path when you do this is typically not determined by distance per se, but by time. Do it too soon and you burn more fuel. Do it too late, and the problem becomes one of not being at Vref when you need to be.


Can I pass the EASA ATPL exams by studying FAA materials?

If you are asking about knowledge - you can use some points, but generally FAA ATP knowledge is insufficient. EASA has 14 subjects, and requires much stronger theoretical background. Just go through the EASA learning objectives and you will see it.

Moreover, there are some differences in Air Law (EASA exam pretends to be ICAO-based only, but in fact it asks about European regulations as well), IFR and VFR communications, and even units of measurement (for example, EASA has some questions where you pick altitudes in metres, not in feet).

And, finally, you cannot even sit the exams without taking a theoretical course in some EASA-approved flight school. That means that you usually need a course completion certificate before going to CAA. There is another way if you have 1500 hours under your belt, but that is a completely different story, and in that case sometimes you don't need to sit the exams at all.


What is the use of this sharp edge found on the leading edge of a DA 40NG wing?

I'm leaving the aerodynamics to someone who paid more attention in classes but, as I remember, that leading edge is supposed to induce flow separation at lower angles of attack (for that portion of the wing), inducing a small buffet into the ailerons and a buffet feed-back to the pilot through the control stick.

Without it, the wing would begin separation (and stalling) at the root, and by the time you get the buffet in the stick the whole wing is basically already stalled.


Is there a fuel injector cleaner additive available?

Fuel injectors in GA piston engines are actually fixed nozzles, so short of fuel contamination, are not so easy to clog,since the only thing that can  be deposited with clean fuel is the blue dye in the avgas.

In 8 years maintaining a fleet of 6 to 8 injected Continental engines, running 200-700 hours / year, I did not see a fuel-deposit blocked nozzle. Deposits did change the flow rate enough for us to routinely clean them ultrasonically (our pilots were cruising lean of peak, and would start complaining), but removing, cleaning and reinstalling the injector nozzles was a routine, straightforward and scheduled event in my experience.

With position tuned nozzles, as current Continental ones are, you need to be careful to get them back to their correct position, just like GAMI ones, but it's not rocket engineering. The torques for installation are in the manuals, and they are not the most challenging item to work on (one b-nut and one pipe thread per nozzle) on the average GA engine. There's no need for special additives.


What happens if a language other than English is used over the radio?

During the 1990s I flew into countries on every continent except Antarctica. As an American English speaker flying U.S. registered airplanes, I never had a complaint that a controller had trouble understanding me, and I was always addressed in English by the controllers. Sometimes, though, I would have trouble understanding the controller's accent and would have to ask them to repeat their instructions.

As you mentioned, in some countries the controllers will address the pilots of that country in their native language. Personally, I always felt that compromised the smooth functioning of the system to a degree, because it denied a good bit of the overall picture of what was happening to the pilots who didn't speak that language. For example, if two airplanes preceding you are being rerouted for some reason, but you can't understand what they've been given (and which you're probably going to be given), you're not as prepared for the reroute when it comes through to you in English.

Even if controllers spoke to you in English, they would typically pronounce place names and fixes as they are pronounced in the native language. My first flights in France were a real problem in this respect. The French controllers were speaking good and understandable English, but the French pronunciation of the place names did not match our English rendition of the names we were seeing (and had never seen or heard before) on the IFR maps (no glass cockpits back then for us). In a couple of instances, we had to request that they spell the names, which didn't make us popular. On one occasion, when we made such a request, another pilot came on frequency and said, "He means ...." and gave us an English transliteration if you will of what the controller was saying.

Interestingly, the worst time I ever had understanding a clearance was one from a nominally English speaking controller. We were talking to Scottish control, and received a reroute into Amsterdam from a controller with a very pronounced accent (Glaswegian?). All I was able to get was that at the end he was turning us over to Dutch control and the frequency. I went over to the Dutch, and asked for them to restate what our new clearance was, and I apologized, explaining that I had been unable to understand Scottish control. His first words were, "That's okay, we can't understand them either."


What are the merits of an inlet cone/spike/centerbody vs. a 2D inlet?

Both are ways to create compression shocks in order to compress and decelerate supersonic air.
Spike intakes
The central spike is characterized by:

undisturbed flow,
light weight and compactness, and
easy adjustability to speed and mass flow at high flight speeds by translating the spike.

Its disadvantages are:

large loss of efficiency with angle of attack and sideslip,
long internal ducting,
limited space for radar installation, and
limited mass flow at low speed.

Typical central spike intakes are those of the MiG-21 or the SR-71, as shown below. Note the variation in cone angle which helps to create additional, steeper shocks such that the flow is gradually decelerated over a sequence of shocks. The inside is filled with a radar system or hollow in case of the SR-71. At the height of the intake lip the SR-71 spike has a perforated wall to suck away the spike's boundary layer, and aft of that it contains the translation mechanism which shifts it back and forth to adjust the intake cross section and to adjust the shock position.

A variant of the central spike is a side intake with a compression half-cone, as used on the Mirage III, the F-104 Starfighter or the TSR-2. Their location at the fuselage side helps to reduce the length of internal ducting and to reduce flow distortion due to sideslip. It also frees up space at the fuselage tip for a larger radar antenna. However, now the fuselage boundary layer has to be split off by a splitter plate to ensure equal flow energy over the whole intake cross section.
The picture below shows the English Electric Lightning with its central spike intake feeding two Rolls-Royce Avon engines, and the side intake of the TSR-2. Note the additional intake doors aft of the intake lip of the TSR-2 which were needed to increase mass flow at low speed.

The F-111 has a quarter-circle spike intake. Here, the wing root also helps to direct the flow, so angle-of-attack variations produce less intake flow distortion. To suck away the intake boundary layer, the spike is perforated at the lengthwise position of the intake lips.

Ramp intakes
What you call 2D-intakes are normally rectangular with an oblique shape. The forward edge is used to create an oblique shock which can be positioned to hit the rearward edge on the opposite side by shifting one or both edges up and down. This also changes the cross section of the intake, so adjustments for mass flow can be made over a wide range. An adjustable ramp aft of the forward edge allows to create more shocks with decreasing obliqueness, such that the flow is decelerated by a sequence of shocks. Typical ramp intakes are those of the F-14, the F-15 or the Concorde. Their advantages are:

Adaptability over a wide range of flow conditions, angles of attack and mass flows, and
tailoring of the shock system for optimum efficiency over a wide range of supersonic speeds.

Their disadvantage is a consequence of the wide adaptability:

High weight and complexity.

Note that the pressure in the intake is a multiple of outside pressure at supersonic speed, so the intake is actually a pressurized duct. A rectangular intake will need massive structural reinforcements to stay in shape while the cross section transitions to a round shape downstream.
The drawing below shows the intake of the F-14 at different flow conditions. Note that the sharp intake lips require them to be exactly aligned with the local flow direction to avoid flow separation.

While a central spike intake is the best choice for flying at the design speed, the rectangular intake works better over a wide range of speeds. The shift in air combat doctrine from flying as fast as possible (1950s) to flying mostly subsonic with brief supersonic dashes (since the 1970s) is reflected in the choice of intake type.
Hypersonic intakes
When flying at Mach 5 and above, the obliqueness of the shock waves will need a very long intake, and effective designs use the lower side of the forward fuselage as part of the intake to create the necessary sequence of shocks for pressure recovery. Now the fuselage nose becomes the forward lip of the intake, and the body is shaped to create ever steeper shocks. Alternatively, the lower forward fuselage is shaped to work like a section of a spike. What looks like the actual intake is actually the rear intake lip, and the divergent section of the intake aft of the rear lip is reduced since the flow in the combustion area is still supersonic in order to keep temperatures manageable, making the engine a scramjet. This answer has more information on supersonic combustion.
Note that this type of intake is optimized for one speed, and very little adjustment is possible. The pictures below show a NASA CFD study of the X-43A (left, source) and the Russian Ajax project (right, source). A scramjet can use both types of intake, and the fuselage design will determine which type it will be.

The rear fuselage now becomes the nozzle of the engine, because most of the expansion will happen after the flow leaves the enclosed part of the engine.


There are (at least) two general points to consider. First, hang gliders are ultralights and the regulations in 14 CFR 103 apply to them. 103.17 says:

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

If you look at a sectional chart, most of the airspace over NYC is class B, including to the surface in many places:

In a class B surface area ultralights require ATC's permission to operate; whether or not the area was congested is a separate issue and nothing to do with the airspace class itself.

Second, as a general statement the FAA regulates what happens in the air but not what happens on the ground. States and counties can make their own rules about launching and recovering aircraft, and national parks have their own rules too. In other words, you need to make sure that wherever you fly your hang glider, it's both legal to launch and legal to operate in that airspace.

Now, let's look at Midland Beach, Staten Island specifically. I've marked the approximate location on the chart with a red dot. It's hard to see because the chart is so crowded, but that part of the coast is depicted as a "special conservation area" and there's also a comment that it's part of the Gateway National Recreation Area, which is a national park.

The airspace there is class B from 1500ft upwards, meaning that if you stay below that altitude then you're OK from the airspace point of view. It's true that the FAA discourages flight over parks, but it's mostly about noise (not a concern in a hang glider) and there's no actual regulation anyway.

However, it seems likely that you were launching from a national park and that does require permission from whichever authority runs it. I have no idea whether or not that's what the NYPD were talking about.

(My personal suspicion is that the NYPD officers just decided "that can't be legal" and made up something on the spot. But there are still actual regulations that do apply, whether or not the officers were fully informed/trained on them or not. I also don't know why the NYPD would want to enforce FAA regulations, but that's a topic for another site.)


There are two recorders that are mandatory on board commercial aircraft: CVR for voice, and FDR for data. They are designed to survive an accident and include an ultrasonic beacon to facilitate locating them underwater.

(Source)

It's worth mentioning that CVR and FDR are not connected to any external data port for data export/copy/extraction, and extraction of the recorders after an accident is done exclusively by the investigating agency.

(As everybody knows for years, these recorders are orange, so there is no need for journalists to continue to call them 'black boxes' as if we were not in the secret too and may not get what they are talking about...)

Cockpit voice recorder (CVR)

The CVR is a sensitive question. Crews have accepted the recording of cockpit conversations to help understand accidents. One condition is the conversations remain private in other circumstances. So there is definitely no other allowed use of the CVR.

Flight data recorder (FDR)

Certain technical parameters, like inputs on the flight controls, must be recorded, also to help determine the cause of an accident. Most FDRs record many more parameters than mandatory. Still the FDR cannot be used in other circumstances than an investigation (see section about data privacy further down).

Using in-flight data for improvement

FDR data causes less privacy concerns than CVR conversations. Safety agencies over the world have encouraged airlines and manufacturers to set up improvement programs (quality improvement) taking into account in-flight technical parameters.

(Source)

Quality improvement initiatives include:

Flight operations quality assurance, FOQA. See FAA AC 120-82.
Flight data monitoring, FDM. See Swiss FDM booklet for crews.

FDM allows companies to:

Compare their flight standards (SOPs) and the crews' actual actions. This is a way to enforce SOPs, and detect deviations from SOPs, hence crews may be reluctant to see this becoming mandatory.
Detect excessive forces applied to the aircraft, that require maintenance checks and/or repairs.
Set fuel consumption improvement actions.

As the FDR data cannot be exported, new recorders used for data monitoring and analysis are now seen on aircraft.

Quick access recorders (QAR)

Quick access recorders (QAR) are used in place of FDR, they allow much freedom, they don't have the same use and disclosure restrictions, don't have to resist a crash and can be included in wireless networks. For example this is Wifi/Ethernet QAR:

(Source)

QAR use the same data acquisition unit (DFDAU) as the FDR, using ARINC 573/717 links. They are essentially duplicating and extending the mandatory FDR, but data can be read at any time using data links. This access is not limited to investigation purposes.

Optical quick access recorders (OQAR) are QARs storing data on optical disks (e.g. Curtis-Wright), and they can record up to weeks or months of flight data. On the other hand, very small "micro" QARs exist too. This well known one uses a CompactFlash card:

(Source)

Countries like India have mandated flight data monitoring and analysis using such devices, but most regulation bodies have taken into account the reluctance of crews regarding the spreading of sensitive data, and the programs remain subject to airline decision.

Privacy aspects of CVR and FDR data

This section is likely very incomplete as the topic is complex.

ICAO:

Investigation-related recommendations are described in Annex 13 to the Chicago Convention on International Civil Aviation: Aircraft Accident and Incident Investigation.

  Non-disclosure of records. 5.12 The State conducting the investigation [...] shall not make the following records available for purposes other than accident or incident investigation, unless the appropriate authority for the administration of justice in that State [...]: [...] b) all communications between persons having been involved in the operation of the aircraft; [...] d) cockpit voice recordings and transcripts from such recordings; 5.12.1 These records shall be included in the final report [...] only when pertinent to the analysis of the accident or incident. Parts of the records not relevant to the analysis shall not be disclosed.

Flight recorder cover both voice and data:

  Flight recorder. Any type of recorder installed in the aircraft for the purpose of complementing accident/incident investigation.

However only CVR is mentioned in the article above, so there is some ambiguity about using FDR data.
The point about privacy is that if the information is disclosed, then the safety agencies may not be trusted in the future, information may not be provided, and security may suffer from this lack of information.

CVR in the US:

  A CVR committee usually consisting of members from the NTSB, FAA, operator of the aircraft, manufacturer of the airplane, manufacturer of the engines, and the pilots union, is formed to listen to the recording. This committee creates a written transcript of the CVR audio to be used during the investigation.

(Source)

  Congress has required that the Safety Board not release any part of a CVR audio recording.

(Source: ibid.).
Read also: "Privileged communications?" The bright line rule in the use of cockpit voice recorder tapes.

Recordings in EU:

Article 14, Protection  of  sensitive  safety  information in 996/2010:

  the following records shall not be made available or used for purposes other than safety investigation, or other purposes aiming at the improvement of aviation  safety: (a) all communications between persons having been involved in  the  operation  of  the  aircraft; [...]. Flight data recorder recordings shall not be made available or used for purposes other than those of the safety investigation, airworthiness or maintenance purposes, except when such records are de-identified or disclosed under secure procedures.

The article above covers both CVR and FDR, but seems less restrictive than the ICAO.

Article 34 in 76/2014:

  In order  to ensure the confidence of employees or contracted personnel in the occurrence reporting system of the organisation, the information contained in occurrence reports should be protected appropriately and should not be used for purposes other than maintaining or improving aviation safety.

Reading the many CVR transcripts available online, it's obvious that this rule has sometimes been transgressed. Authorities have now difficulties when making the proposition to increase the legal duration of the recordings from 2 to 24 hours.


Why does placing one hand on the head track stabilize you during turbulence?

He's just saying that you can brace your torso, and transfer the airplane's movements into your torso better so you don't sway around relative to the floor, by holding something rigid with your hand anchored at or just above shoulder level.
If you've ridden in a subway car that is rocking back and forth while standing up, holding on to a vertical post, you've probably noticed it's better to hold the post with your hand about level with your head, vs holding it down at your waist.  With your hand up high the car's motion is easy to transfer to your torso so you can stay more rigidly connected and you move as if you were part of the car.  Hold it down lower and you notice your torso tends to rock about the lower anchor point and your upper body sways more relative to the post, and this makes it a lot harder to stabilize yourself.


Does the tailwind component always have the same absolute value as the headwind component?

YES, If the "amount of headwind" was 10 knots due to the crosswind, then the "amount of tailwind" would also be 10 knots on the reciprocal course.

BUT, because the 10 knot disadvantage with a head wind will last for a longer period of time than the 10 knot advantage with a tailwind, the entire trip will take longer and use more fuel than a trip in still air.

EXAMPLE: The headwind leg is 15 minutes longer, but the tailwind leg is only 10 minutes shorter, so you have a net loss of time.


What if a flight, transporting a recorder from an aviation accident, crashes?

If the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) need to be transported by airfreight, to expedite extraction of the recorded data and analysis of the accident, the probability of the aircraft used to ferry the devices crashing is rather low, as aircraft accidents do not happen as frequently compared to the total of movements per day/week/month/year.

Nevertheless, in the event of the aircraft used to ferry the devices crashing, the FDR and CVR are built to survive crashes and impact, so the probability of the first pair of FDR and CVR being still usable for data extraction after a second crash is quite high.

Since the FDR and CVR record not only data but also timestamps along with the data, the distinction between the FDR/CVR from the first crash and the FDR/CVR from the second crash is not a problem. Upon data extraction, the investigating party would recognize which flight parameters belong to which flight. Additionally, if the FDR and CVR on both flights were identical models, the serial number of each device would help identification.


How can I find a final approach fix (FAF)?

For precision approaches, the Final Approach Fix (FAF) is defined as one of three points:

A lightning bolt symbol on FAA government approach plates
The (published) glide slope/path intercept point on Jeppesen approach. The glide slope/path symbol depiction starts at the FAF on these plates.
Or, it is the resultant actual point of the glideslope/path intercept when ATC directs a lower-than-published glideslope/path intercept altitude

Since FAA government (NACO) charts answer your question with the depiction of the lightning bolt symbol, your question applies primarily to Jeppesen charts (other chart vendors perhaps as well). Jeppesen charts include the glide slope intercept altitude in the briefing strip near the top of the plate. So, the FAF for precision approaches is the location at which glideslope intercept is to occur when at the lower of either the published or ATC directed altitude.

See the following excerpt from the FAA's Pilot/Controller Glossary:

  FINAL APPROACH FIX− The fix from which the final approach (IFR) to an airport is executed and which identifies the beginning of the final approach segment. It is designated on Government charts by the Maltese Cross symbol for nonprecision approaches and the lightning bolt symbol for precision approaches; or when ATC directs a lower-than-published glideslope/path intercept altitude, it is the resultant actual point of the glideslope/path intercept.

See the following excerpt from Jeppesen's Airway Manual:

  FINAL APPROACH FIX (FAF) — The fix from which the final approach (IFR) to an airport is executed and which identifies the beginning of the final approach segment. It is designated in the profile view of Jeppesen Terminal charts by the Maltese Cross symbol for non-precision approaches and by the glide slope/path intercept point on precision approaches. The glide slope/path symbol starts at the FAF. When ATC directs a lower-than-published Glide Slope/Path Intercept Altitude, it is the resultant actual point of the glide slope/path intercept.


How to Recover from a Spin in Cessna 172?

The memory aid is PARE:

POWER to idle
AILERONS neutral
RUDDER on the floor opposite the direction of spin
ELEVATOR nose-down to break the stall

You will want to read the full explanation in the Pilots Operating Handbook or POH for an understanding of the steps and why you need to take them. Commit the sequence above to memory and better yet get spin training from a qualified instructor.

The POH for the 172N model reads (caps and boldface in original):

  Should an inadvertent spin occur, the following recovery procedure should be used:

  RETARD THROTTLE TO IDLE POSITION.
  PLACE AILERONS IN NEUTRAL POSITION.
  APPLY AND HOLD FULL RUDDER OPPOSITE TO THE DIRECTION OF ROTATION.
  JUST AFTER THE RUDDER REACHES THE STOP, MOVE THE CONTROL WHEEL BRISKLY FORWARD FAR ENOUGH TO BREAK THE STALL. Full down elevator may be required at aft center of gravity loadings to assure optimum recoveries.
  HOLD THESE CONTROL INPUTS UNTIL ROTATION STOPS. Premature relaxation of the control inputs may extend the recovery.
  AS ROTATION STOPS, NEUTRALIZE RUDDER, AND MAKE A SMOOTH RECOVERY FROM THE RESULTING DIVE.

    NOTE

    If disorientation precludes a visual determination of the direction of rotation, the symbolic airplane in the turn coordinator may be referred to for this information.

Other Spin Recovery Methods

The methods below may or may not recover from all spins. Seek out a qualified instructor for spin training — or, better yet, avoid spins altogether!

Finagin

  Finagin advocates a four-step recovery technique for unintentional spins and departures from controlled flight that pilots can put to use without hesitation — and without fear of making the situation worse — even when they’re confused or disoriented by the unusual attitudes and strange sensations that can accompany spins.

  Rip the power to idle.
  Forcefully neutralize the stick and rudder pedals.
  Look at the airspeed indicator, and once it shows 100 knots or more (roughly 1.4 times the airplane’s stall speed) …
  Pull out of the dive.

Source: AOPA

Beggs-Mueller

  Power – Off.
  Remove your hand from the stick.
  Apply full opposite rudder until rotation stops.
  Neutralize rudder and recover to level flight.

Source: Spins in the Pitts Special by Gene Beggs

Hands In Your Lap

Some advocate the “hands in your lap” method of pulling power, taking your hands (and feet) off the flight controls, and waiting for the airplane to fly itself out of the spin. This may work for certain airframes but not all. Catherine Cavagnaro of Ace Aerobatic School says she likes to perform spin training in a Cessna 152 because that airplane will not self-recover from a spin.


Could Falcon 9 fairing become glidable / flyable?

Currently the fairing is separated at about 100 km altitude, when the aero-thermal flux drops below 1135 W/m2. So it's not separated outside the atmosphere, the fairing still experiences noticeable drag.

That means the fairing has to be separated from the stage quickly, to prevent it crashing into the payload. With 2 fairing halves this is easy: the two halves can push against each other (using simple pneumatic cylinders or pyrotechnics), and both will move away from the stage in a straight line. By pushing with slightly more force at the top of the fairing, the halves are pushed in a direction where the wind will make sure halves are pushed farther apart.

If you were to hinge the fairing, you can't do that any more. You get two events:

open the fairing. One half hinges open while the other one has to stay in place.
once it's opened far enough, apply thrust to get the fairing away from the payload.

You can't do this under aerodynamic load:

the wind will exert a force on the fairing. One wobble in the wrong direction and the fairing will be pushed closed again.
the half-open fairing is not stable. The nose cones will be pushed inward by the wind.

So you'd have to separate the fairing at a much higher altitude, which reduces the payload of your rocket by a significant amount. It also means the fairing is separated at a higher speed and becomes more difficult to recover.

Mechanical actions are always a risk. A hinged fairing adds to that risk: the timing is critical, and the actions have to be carried out under load from acceleration.

JWST deployment and Shuttle robotic arms have fewer time constraints, and the actions are carried out without a load.


What are the speeds for absolute ceiling and coffin corner?

At absolute ceiling we can fly at only one speed. This is the speed
  which corresponds to intersection of power available and power
  required curves?

The "intersection of power available and power required" is anywhere along the left hand edge of the red cross-hatched area. The absolute ceiling is the intersection of the stall curve (left-most red line) with this power limit.

  And what is that speed at which flight at Coffin Corner is only possible?

Coffin corner in that chart should be the intersection of the red stall line with the black MMO/VMO line.

I say 'should be' because the stall line is drawn with a maximum at the  "absolute aerodynamic ceiling" i.e. the plane stalls if it goes any faster or slower. Stalling when going faster must be due to increased Mach number.

In other words, the right hand side of the stall line is actually the maximum Mach number, which would make the "absolute aerodynamic ceiling" 'coffin corner'.

I suspect the confusion is that they wanted to draw MMO as a (mostly) straight line, and didn't think it mattered because the plane doesn't have the power to reach that region.


What is the difference between Cloud Ceiling and Cloud Base?

They are not the same thing.  Cloud base is simply the bottom "surface" level of the a cloud regardless of the sky coverage.  Where cloud coverage constitutes a ceiling, then the cloud base would be the same as the ceiling, but regardless, the bottom margin of any cloud is its base.


When buying an aircraft which has had multiple owners it is acceptable to get the logbooks from the previous owner only?

It will most definitely decrease the value of the airplane. How much is not easily answered. If the current owner has owned the plane for a long time and all the ADs are complied with then probably not much of a decrease in value. If they have replaced the engine and prop—even better. However, if the current owner has had it for a short while, then maybe he’s selling it for a reason related to the missing logs.

Maybe there was a prop strike or gear-up with a previous owner and they didn’t do the repairs properly. Or maybe there is a lien on the plane from when the last owner didn’t pay the shop. Or it could be that the plane was perfectly maintained but an ex-spouse kept the books in a nasty divorce. That’s why it is difficult to say how much the missing books decrease the value.

You can get the records for the airplane from the FAA in Oklahoma City to see if there was major damage properly repaired. The A&P is supposed to file 337s for major repairs and modifications.

In any case, you’ll need to have an A&P who is familiar with the type do a careful pre-buy.

Whether you should buy a plane with missing logs partly depends on how long you intend to keep it. Just like you are concerned about missing logs, the next owner will be too. If you plan to keep it for a long time, then you probably shouldn’t be too concerned about the difficulty of selling it later. If it’s a transition airplane for you, then know that it will be more difficult to sell.


Do airline pilots increase thrust when ordered to increase altitude by traffic controllers?

Do airline pilots increase thrust when ordered to increase altitude by traffic controllers

Yes, without increasing thrust the act of ascending would reduce speed.

  Do they simply use flaps

No, flaps are not used to climb. They are used to increase the surface area of the wing in order to allow the aircraft to fly at slower speeds (for example, during approach & landing).

  What is the altitude increase sequence or procedure

Generally, and put simply, it is increase thrust then raise the nose.

  Do they simply rely on auto pilot and if so does it increase thrust too?

They may well use the autopilot to do it all, but some autopilots do not control the throttle so that would be done manually by the pilot while the autopilot controls the rate of climb.


Why do I get that funny stomach drop feeling right after takeoff?

It happens when the airplane levels off after takeoff, usually either at the first assigned altitude or at a safe altitude where it will be accelerated in order to retract the flaps.   The feeling is a result of negative vertical acceleration.  It can also happen at other times during the flight, such as during turbulence or when starting a descent.

Basically you and the airplane are both in a steady climb and when the aircraft levels off you continue to move up faster so it (via the seatbelt) keeps you at its same level and decelerates your own personal vertical climb.

It is just like the feeling you get in a roller coaster.

My wife calls it a wee-hill!  :-)

EDIT:

Another more familiar example happens anytime that you are traveling in a car:

If you are in a car moving at a constant speed (let's say 55 MPH) you are moving at the same speed along with it.

When the brakes of the car are engaged, they slow the car down but your inertia tends to keep you moving in the direction that the car was going.  This will be more noticeable as the brakes are applied harder and harder because the deceleration of the car is more extreme.

You will notice this as pressure against the seat belt as the car holds you in place.  You are still moving forward, but you are getting slower (decelerating).  In an airplane the exact same thing is happening only it is in a vertical direction instead of a horizontal direction like in the car.

What you are feeling is your stomach floating up a little inside your body, because while the seat belt is holding you down, it doesn't hold your stomach in place!


Your question is flawed because you have labeled the airspace incorrectly:

The thin circular magenta line you have labeled class C is actually the edge of the 30 mile mode C veil around SEA.

The shaded magenta line you have labeled class D actually depicts the area where the class E floor is 700’ AGL.

If you want to see how class C airspace is normally depicted, look North to NAS Whidbey Island.
If you want to see how class D airspace is depicted, come halfway back to Paine Field in Everett.  (There is also class D around SEA, BFI and RNT, but they overlap each other and the chart is pretty busy in this area, so Everett is a cleaner example.)


About how many aborted takeoffs are there each year in commercial aviation?

As off today (March 21st), Aviation Herald lists 26 rejected take-offs, in 2018.

It's 110 days since the start of the year. So that's 110/365ths, or 0.31 of the year. So, the whole year will have 26/0.31, or about 84 rejected or aborted take-offs.

This assumes, all are reported in Aviation Herald, which is probably not true, so the real average number is likely to be higher. But that's a rough starting point, and probably the best estimate you will get.


How to calculate airfoil geometry with the maximum lift to drag ratio for a given Reynolds number?

The optimum airfoil is a cambered line of zero thickness. If operated at just the correct angle of attack, it will produce the highest L/D possible. It's cross section is trivial: It has none. However, it will not allow to build a clean wing since it has no space for a spar. It would need to be kept in shape by lots of wire bracing, and then the overall L/D of the resulting aircraft would be horrible.

Next, if the angle of attack is only slightly different from the optimum value, the sharp leading edge will cause early separation on one side, causing the L/D figure to plummet. This airfoil will not be practical for any purpose other than establishing a theoretical optimum figure.

Real airfoils need a blunt nose and some thickness. There are plenty enough airfoils to choose from already. All of them were designed not just for one single design point, but as an overall compromise to cover a wider range of parameters in real-world operation.


What are typical values of the lift-to-drag ratio for normal small aircraft?

The maximum L/D values for existing aircraft span a wide range, from 7.5 for the Zodiac Ch701 with floats to 21.5 for the Berkut 360. Source: Light Sport and General Aviation Airplane Comparison and Harloff Performance Factor. This comparison comprises 93 types, and that is normally where a drag calculation starts: You find a similar type and use that as a baseline.

For the wing drag you calculate the lift distribution for several angles of attack (try XFLR5 for this) and get the induced drag for the weights and speeds that belong to those angles. Now you need to know your airfoils and add their drag. Next, add increments for the interference with the fuselage, for fairings, gaps and probes using data from this book. Yes, it is more than half a century old but physics hasn't changed since then.

Drag is normally not the biggest in-plane load on a wing but lift at high angle of attack. If you need to calculate loads for a structural design, make sure you don't omit that particular load case. Don't be surprised: That lift has a strong forward-facing component.

If you are new to this, try to calculate several of the aircraft for which data exists. Only by doing this you can be sure that what you do gives good results. Drag calculation needs some experience and is, when done well, a lot of work.


Yes, it's safe. It's taught to scuba divers as a standard method for equalizing air pressure, with the general caveat that it should never take too much effort and if you feel any pain or discomfort from doing it then you should stop diving and consult a doctor. Since pressure changes in the air are much more gradual than those underwater, it shouldn't be difficult at all to equalize in an aircraft.


What type of engine/motor is used in aircraft APU?

Since the only fuel available on an airliner is kerosene, the APU is a kerosene-powered jet. Using a different and maybe more efficient type of engine would require an independent fuel system, which does not make sense for the small savings possible.

From the 737.org page on APUs:

  There are many different APUs available for the 737. The most common
  is the Garrett GTCP (Gas Turbine Compressor [air] Power unit
  [electrics]) 85-129. This was standard for the series 1/200 but when
  the -300 was introduced it was found that two to three times the
  energy was needed to start the larger CFM56 engines. Garrett produced
  the 85-129[E] which had a stretched compressor, ie the impellers were
  lengthened and the tip diameters increased. When the 737-400 was
  introduced, even more output was required and Garrett produced the
  85-129[H]. This has an Electronic Temperature Control which limits hot
  section temperatures depending upon demand and ambient temperatures.
  By 1989 the 85-129[H] was the most standard APU in all 737 models,
  although there are actually 14 different models of the 85-129 in
  service with 737s.

To answer your question about the 737 NG, it continues:

  Other APUs available are the Garrett GTCP 36-280(B) and the
  Sundstrand APS 2000 on the 3/4/500; and the Allied Signal GTCP 131-9B
  for the NGs. The main difference between them is that the Garrett is
  hydro-mechanical whereas Sundstrand and Allied Signal are FADEC
  controlled.

Be sure to load the 737.org page, it has lots of pictures and data on the APUs.


How does thrust reverser selection have a destabilising effect on the rudder and increase the lateral skidding tendency of the aircraft?

This is called rudder blanking. While I was searching for it, I came across this image

(Source)
As the Skybrary article mentions

Rudder blanking is a particular risk to aircraft with rear mounted engines and "T" tails.

I emphasized the word particular since I perceive it as an indication that it's a risk for other planes as well without rear mounted engines.
Now the flow from trust reversers, disturbs the airflow around the rudder reducing its effectiveness. In strong crosswind you rely on rudder to keep the aircraft centered on the runway. If you apply thrust reversers right after touchdown, you reduce the effectiveness of the rudder and in turn it might reduce the crab angle making it harder to keep the aircraft centered.
Addendum
I will try to explain with a graphic, though as I've already stated in my comment, I'm not an expert.
As you can see in this image taken from Wikipedia, the thrust reverser output is not blocked by the wing, so it's quite safe to assume there is a jet similar to the first image.

I would estimate that the area of that vertical jet is more or less contained in the red circle seen in the next image. The free stream will push the turbulent jet from the reverser towards the back (as you can see in the first picture) and disturb the flow around the fin. The orange area is parallel to the free stream and shows the direction of the turbulent flow which might not be exactly the same in reality as the fluid particles have a tendency not to follow straight lines.
The plane is rotated 15 degrees to simulate a moderate "crab angle". From the picture posted in GdD's answer, you can assume this can be more if the vertical wind component is high enough.

(Source of original image)
Now one thing you might need to consider is that the engines of a wing mounted engine plane have significantly more distance from the vertical stabilizer compared to the tail mounted engine plane. That distance might be able to weaken the effect of the stream, enough to not cause accidents like this mentioned by Sports Racer in his comment. But that doesn't mean the problem is not there, hence the warning from Airbus.


Are Uber Elevate and other air taxis subject to domestic ownership and control rules?

The most important thing to remember is that currently there is only one FAA regulation about person-carrying autonomous drones: it is simply not permitted.

Both 14CFR Part 121 (airlines) and Part 135 (charter/air-taxi) have ownership and citizenship requirements. (It is of course not known what Part person-carrying drones would be under, but we can assume similar requirements.)

However why should this affect Uber? They do not own the cars that are currently in the fleet; in exactly the same way they could have the aircraft be owned not by Uber, but by some sub-contractor.


What is the object on the nose of this HondaJet in this marketing video?

It is a Pitot tube.

It is used to measure some air data values, depending on the model.

The most basic will measure only pressures (and then "derives" the velocity of the aircraft), the most advanced will measure angle of attack and sideslip as well.

The one in the photo is particularly long to make sure that is measuring values in the undisturbed airflow in front of the aircraft. It is a model usually seen in flight tests or on fighter aircraft.

In flight tests, because despite the accurate CFD modelling available today, uncertainties are still present during the first flights (that's why they are tests). The long probe gives a reference as much undisturbed as possible.

During normal operations you will generally find smaller probes, such as the ones found in this other question.

Fighter aircraft need the long boom for the reasons seen in this question.


What is the method to find the resonance frequency of a PowerFlow exhaust?

I think there is a misconception with how these systems work.  These are 4-to-1 or 6-to-1 header systems, as used on cars, and the primary feature of a header system is that the pipes between the exhaust ports and collector are exactly the same length, which is why, on cars, they snake this way and that, because the port closest to the collector has to have a pipe that is just as long as the port farthest away.

The objective is the make sure the exhaust pulse from each cylinder reaches the collector at an evenly spaced interval to minimize interference between the pulses, and also to have the low pressure behind each pulse help pull the next pressure pulse into the collector (they are sometimes called "extractor" exhaust systems because the pulse timing creates a kind of suction effect).

The timing of each pressure pulse's arrival at the collector is the key factor.  To the extent that tuning goes on, it's to make tiny adjustments in pipe length to account for small variations in pulse timing due to different pipe contours - a pipe with more bends may need to be shortened a tiny amount to because its pulse arrives a bit late because of its more convoluted path.  In other words the tuning is the ensure the pulses are arriving at the collector evenly spaced.

From a performance standpoint, longer equal-length pipes are better than shorter equal-length pipes because the inertia of the flow stream is higher and this helps evacuate the cylinders better, enhancing the whole suction effect, kind of the inverse of the slight supercharging effect of long intake runners on the intake side.

The short stack Powerflow system gets 85-90% of the gain because it's still a 4-1 header, which is the primary feature; it's just that with shorter pipes there is a bit of efficiency loss from the shorter flow run compared to long pipes. You also save a couple pounds with less piping.


Why does the US Marine Corps fly the Harrier, a VTOL or operationally STOVL aircraft?

Because when selecting aircraft the requirements were for close air-support and to be able to operate from amphibious assault ships like the USS Tarawa and the USS Nassua.

These ships have very small decks that aren't geared towards launching larger aircraft like the F-18.


Can civil pilots *ever* fly military high-altitude penetration approach procedures?

As long as you can actually make the altitude restrictions, then yes, there's no reason why you cannot request to fly the approach.  However, as a general courtesy, you should also factor in your approach speed.  ATC might not appreciate a Cessna clobbering the approach 34 miles out.  These approaches are typically flown at 250+kts, so just keep that in mind.


How much cheaper would flying be if we made it less safe?

Lets completely remove liability from the picture. The airlines are simply not responsible for anything that happens to the passengers, and as a result they don't care. Seatbelts, oxygen systems, escape slides - who needs them? Flight recorder? In the trash. FAA staff are cut to 20% of current levels and are mainly concerned with keeping things running smoothly (their pay is docked across the board when flights are late) and the NTSB is defunded.

Daily operating costs go down a bit. We've removed a couple of hundred kilograms of safety equipment and that will make a small dent in the fuel bill. But only a small one. The mini-Starbucks installed where the over-wing exits used to be weighs about the same. Costs related to FAA-mandated paperwork are eliminated, but only temporarily.

There's less training for the cabin crew, but we can replace the evacuation training with sales training to bump up profits from regular and duty-free sales. Hooters re-enters the air carrier industry and does quite well, as cabin crew can be transferred directly from the restaurants skipping all that troublesome FAA qualification business.

But we find that maintenance costs don't go down. Costs plummet for the first year, but then go back up as management realizes that an airplane on the ground because it won't start costs a lot more in losses than maintaining it properly to begin with. And the one that crashed on takeoff was a complete loss on the airframe ($100mil and up) along with a dent in sales for the following 6 months.

Flight recorders are reinstalled as they are actually rather useful to predict if something is going to break. It can then be replaced by the night shift. The FAA paperwork we stopped doing is also quite useful for deciding wether or not to overhaul the wheel bearings with winter-weight grease, as we wrote down when it was last done.

The flying public will see maybe 10% reduction in fares. Remember that a very large percentage of ticket costs are taxes. For example, flying out of the UK costs up to £194 just for taxes. Wether the public will accept a large decrease in oversight for a small decrease in fares, or wether the long-term accident rate actually goes up or down will be a very interesting social experiment.


How to calculations deviation on a magnetic compass and effect of it?

We think of the earth as having a grid of lines covering it, which re use for defining a grid-position for a place, and for using as the basis for angles for defining our direction to travel from one place to another. These grid lines are latitude and Longitude, but they are a purely-human imaginary idea, they do not physically exist.

The Earth does have a naturally-occurring magnetic field, which at the moment is coincidentally vaguely aligned with the lines of Longitude. And this magnetic field has the huge advantage that its direction can be sensed using some very special lumps of rock, ie with a compass.

Problem 1 - the magnetic field is not actually aligned with the lines of Longitude, so there's an error. This mis-alignment is called Variation (sometimes called Declination in American books) and it's a simple geometric difference between the compass pointing at one place versus pointing at another place; so the value of Variation changes depending on where in the world you are. And this is complicated by the magnetic field moving over time!

Problem 2 - you insist on mounting your compass inside a ship/vehicle/airplane which is made of meta or has large lumps of metal in it, which will push or pull the Earth's magnetic field as it passes through the ship/vehicle/airplane. This causes a directional error in your compass which is called Deviation - and this varies depending on which direction your vehicle is pointing, ie depending on where the lumps of metal are around your compass.

The acronym for working with all this is T-V-M-D-C ("True Virgins Make Dull Company"). So starting with a bearing that you measure from a chart in degrees True, you add Variation to get degrees Magnetic. Then you take into account your particular vehicle by adding in Deviation to get degrees Compass. If you fly degrees Compass, you will be flying degrees True, but you've taken into account where you are, when you are, what vehicle you're in a dn what direction it's pointing.

Simples!


Has any prior accident been caused by a psychologically unstable and/or suicidal crew member?

Confirmed (or Highly Probable)

LAM Mozambique Airlines Flight 470: A report from the government of Mozambique states that the captain deliberately crashed an Embraer 190 in Namibia on November 29, 2013. Cockpit voice recorders were the primary evidence in the report, which found that the other crew members were locked out of the cockpit by the captain. There were 33 fatalities, and Mozambique Airlines was banned from flying in EU airspace. No psychological overview was done of the officer.
EgyptAir Flight 990: A Boeing 767 crashed near Nantucket (Massachusetts) on October 31, 1999, killing 217 people. It was found that the first officer, was responsible. The NTSB and the Egyptian Civil Aviation Authority both conducted individual investigations. The Egyptian report states

  [the] First Officer . . . passed his full medical examination and psychiatric
  assessment, which was performed by the Egyptian Air Force Medical Council as part of his full medical examination for fitness to be a pilot in the Egyptian Air Force, on December 11, 1958. He passed his medical examination for his Commercial Pilot license on July 27, 1961. A psychiatric assessment was not conducted as part of the medical examination for the relief first officer’s medical review for his Commercial Pilot license. During his military and civilian flying career there was no reported history of psychiatric consultation nor any reports regarding his behavior, either professionally or in groups.
  . . .
  First, there is no evidence to support a conclusion that the First Officer intentionally dove the airplane into 142 the ocean in fact, the evidence available refutes such a theory, a determination confirmed by expert medical opinion, technical and human performance analysis.

The NTSB did not agree that the most probable cause was a mechanical failure. Their conclusions, and the relevant rebuttals by the Egyptian investigators, can also be found here.
SilkAir Flight 185: On December 19, 1997, a 737 operated by SilkAir crashed in Indonesia, killing all 104 people on board. The aircraft was almost entirely obliterated. The Indonesian NTSC report (link broken at the moment) said that the cause was impossible to determine. The pilot appeared to be mentally stable, but there have been some doubts. Cockpit recorders stopped at some time, making the case different from that of, say, JetBlue Airways Flight 191 (see below). The NTSB was not happy, severely criticizing the Indonesian findings. Their analysis seem to rule out mechanical issues.
Royal Air Marco Flight 630: 44 people were killed in a crash in Morocco on August 24, 1994. A government investigation ruled it an intentional suicide
Japan Airlines Flight 350: The crash of a DC-8 on February, 1982, was caused by actions taken by the captain before being restrained by other crew members. Because of their actions, the majority of the people on board survived.
1999 Air Botswana Incident: On October 11, 1999, an Air Botswana pilot deliberately crashed an Aérospatiale ATR-42 into two other planes on the tarmac at Sir Seretse Khama airport, killing only the pilot. He was the only one on board, having taken the plane rogue and then flown it about the airport for hours. All the planes were destroyed, though the other two were unoccupied, as the airport had been effectively shut down. The pilot was on medical suspension.

'Close Calls' but no resultant accidents

JetBlue Airways Flight 191: Midway through the flight, the captain of the aircraft appeared to suffer a nervous breakdown. He began yelling about religion and was eventually subdued by passengers after being locked out of the cockpit by the first officer. He was charged with "interference with a flight crew", according to the FBI, which said

  As the plane was leaving JFK and climbing in altitude in its scheduled five-hour flight, [the captain] said something to the first officer (FO) about being evaluated by someone, but the FO did not know what he meant. [The captain] then talked about his church and the need to “focus” and asked the FO to take the controls and work the radios. [The captain] began talking about religion, but, according to the FO, his statements were not coherent.

I also found the same incidences as cpast, from Yahoo! News.

On some of the flights listed, the results of the investigations deemed the pilots obviously mentally unstable. On others, though, the conclusions were disputed, and it may not be possible to truly prove the cases one way or another.


Why does the elliptical wing planform have two different types of curves?

It's because the center axis for the ellipses has to be along the thickest section of the wing, because there is also a taper in thickness that must be accommodated as the ribs get smaller and smaller toward the tip.  In your sketch, the thickest section is at 40% of chord and the taper in both planform and thickness must be oriented to that 40% chord line, hence the asymmetrical curves.
The placement of the axis of maximum thickness is a function of the particular airfoil selected, that is, the point of maximum thickness of the airfoil section itself.  For structural efficiency, this is normally also the location for the main spar. In the sketch, which resembles a Spitfire wing planform, the broken line will be more or less the main spar location, with the nose ribs on the left and the main ribs on the right, with the ellipse curves placed to maintain the 40% forward/60% aft ratio out to the tip.
If the thickest section of the wing was at 50% of chord, then the ellipses would be symmetrical.


What are the differences between FADEC and EEC systems?

The EEC is the Engine Electronic Controller, the digital processing heart of the Full Authority Digital Electronic Controller. Kind of like the microprocessor in a digital computer. From The Jet Engine by Rolls Royce, 5th edition:

The EEC is dual redundant with all subs-systems such as sensors, cables etc duplicated, so that a single fail leaves the system fully operational. It is housed either in the airframe, or like in civil airliners on the engine, leaving it in need of protection of extreme circumstances:

Temperature - ice and tropical heat.
Electromagnetic radiation - lightning and airport radar
Engine vibration

The FADEC monitors inputs such as:

Shaft speeds
Engine temperatures
Oil pressures
Actuator positions
Power setting

and then sets fuel flow, variable stator vanes, and air bleed valves.