Can a civilian aircraft pilot see a missile coming?

Visual detection

To take one example, a vehicle-launched ground to air missile system (e.g. the SA-11) that can reach the cruising altitude of airliners travels at several thousand miles per hour and takes perhaps 30 to 40 seconds from launch to reach its target.

Pilots don't have an especially good view of the ground immediately below and would have a very hard time spotting a missile travelling at those speeds.

Electronic detection

Civilian airliners are equipped with a collision avoidance system called TCAS. However this relies on radio signals from transponders which are fitted to other aircraft. Naturally, anti-aircraft missiles do not have a transponder and do not advertise their presence.

Missile Countermeasures

Anti-missile systems that are available (example) are mainly intended to protect against small infra-red seeking man-launched air-defense missiles (MANPADs) rather than larger more sophisticated radar-homing systems.

Even these systems are not fitted to all civilian airliners, probably only to those that operate into airports where there is a current known risk of MANPAD use by terrorists or other armed factions.

Evasion

Civilian aircraft are not designed for high-G evasive maneuvers and in any case, the missile does not have to strike the aircraft, it detonates nearby based on a proximity fuse and the resulting explosion and high velocity fragments will do enough damage to result in the destruction of the target.


Who has the final authority over sidesticks?

If they were fighting, intentionally attempting to gain control over the stick, the pilot pressing the last would win. This differs from the situation in a cockpit with coupled controls, where the pilot who pushes hardest wins. So in an Airbus, a quick pilot wins from a strong pilot..
From the FCTM:

When the Pilot Flying (PF) makes an input on the sidestick, an order (an electrical signal) is sent to the fly-by-wire computer. If the Pilot Not Flying (PNF) also acts on the stick, then both signals/orders are added.
Therefore, as on any other aircraft type, PF and PNF must not act on their sidesticks at the same time. If the PNF (or Training Captain) needs to take over, the PNF must press the sidestick priority pushbutton, and announce: "I have control".
If a flight crewmember falls on a sidestick, or a mechanical failure leads to a jammed stick (there is no associate ECAM caution), the "failed" sidestick order is added to the "non failed" sidestick order.
In this case, the other not affected flight crewmember must press the sidestick priority pushbutton for at least 40 seconds, in order to deactivate the "failed" sidestick.
A pilot can at any time reactivate a deactivated stick by momentarily pressing the takeover push button on either stick.

Flight International featured an article on the A320 on 30 August 1986. It discusses the sidesticks, which were new for civil aviation at the time, and an Airbus representative makes an interesting point:

"If sidesticks were the normal way for flying aircraft, no one would even consider changing to a control column that makes it difficult for the pilot to get into his seat and which blocks his view of the instrument panel when he's there.."

It is really hard to find an unassociated person though, who is of opinion that uncoupled sticks are better than coupled sticks.


What exactly are the functions of an aviation headset?

Aviation headsets are just like gaming headsets on a computer or console gaming system, except they are sturdier and much more expensive.

At the basic end of the spectrum, an aviation headset is just a big clamp style pair of around the ear headphones with a microphone.  The cable from the headset has 2 plugs (for airplanes) or one plug (for helicopters).  These two plug styles are equivalent electronically, with the helicopter cable having an extra conductor in order to include the microphone and headphones in the same plug. The two-plug variant has one plug for the headphones and one of the microphone.  These differ from gaming headsets in that the headphone plug is 0.25" (the kind a nice stereo receiver uses) and the microphone plug is 0.206".  This difference in sizes is to avoid mixing up which plug goes in which jack.

Aviation headsets fall into two broad categories: passive noise reduction and active noise reduction (ANR).  The passive noise reduction headsets rely on a good seal around the ear and a strong clamping force (e.g. David Clarks).  Active noise reduction are somewhat less "clampy" and provide less passive protection but make up for this with the active protection.  An ANR headset is money well spent, but these do top out at around \$850-\$1000 for the top models from Lightspeed and Bose respectively.  ANR headsets must be powered to work properly but all ANR headsets still function without power as passive noise reducing headsets.  Power for an ANR headset can come from a battery box or from aircraft power but not interchangeably.  Aircraft power requires panel installation of a plug specific to the headset brand (a single connector provides power, headphone and microphone connections).  In general, unless you happen to own an airplane and install the power plug, you should get the battery version of a headset.

The primary purpose of these headsets is to reduce the noise in the cockpit (they can be very loud) in order to avoid hearing loss (yes, it is that loud) and to facilitate clearer communication with ATC.

For quieter airplanes there are in-ear headsets that have more in common with earbuds than the bigger headsets.  Some of these are just earplugs wired for sound and some use molds of your ear to provide the seal.

The headset is connected to the airplanes audio panel.  Audio panels vary in complexity but their basic job is to provide an intercom for communication between occupants of the airplane and access to the com radio for communication with ATC.  The audio panel is also able to monitor (listen) the navigation radios certain types of beacons.  In transport aircraft the audio panel is also tied into the passenger address system and the flight attendant's phones in the cabin.

The headsets can be operated in a hot mic setup or the mic can be explicitly turned on and off.  The hot mic is the usual method and the audio panel provides a squelch control so you aren't broadcasting the cockpit noise when not talking.  The ATC transmissions are via a push-to-talk (PTT) switch.

Aviation headsets for the most part do not need to be approved to use in airplanes, but in some situations for US registered aircraft, the requirement of an approved headset can be mandated (some (all?) 121 carriers).  The FAA standards for approval are specified in TSO C-57a and C-58a.  You'll find many, but certainly not all, aviation headsets conform to these orders.  They define minimum performance characteristics of the electronics, speakers, microphones, etc that make up the headset.

How much hearing protection is needed depends greatly on the specific airplane in question.  Jets can be on the very loud end of the spectrum (EMB-145) or they can be quiet enough that even passive noise reduction is largely unnecessary.  For the noisy end of the spectrum peak wavelengths can be well in excess of 100 dB.  I can find reports of 130 db in some smaller airplanes and reports of 84 db in a 737 during cruise, but these numbers are all anecdotal in nature.  What is important to take from these is not the specific numbers but that they are high enough to cause hearing loss during prolonged exposure.  The National Institute on Deafness and Other Communication Disorders defines 85 dB as the threshold for hearing damage from long or repeated exposure.

Passive headsets generally advertise noise reduction around 20 dB (23 dB for the venerable David Clarks) and some people will wear earplugs under a headset to further increase the passive noise reduction. A cursory look at ANR headsets reveal that they tend not to advertise their performance and instead specify maximum ambient noise levels for ANR to properly function (around 120-125 dB for Bose and Lightspeed headsets).  I can personally add an anecdote that both the Lightspeed Zulu and Bose X make dramatic changes in noise level (both of these headsets are now outdated and replaced by newer versions).

For most smaller airplanes you will wear the headset from startup to shutdown.  As you get into the large jets I have observed crews that wear minimal headsets during takeoff and landing, but not always during cruise.  These airplanes were quiet enough that they were not needed.  On turboprops and smaller jets that I have been in, headsets were worn throughout the flight.

On newer ANR headsets in particular you will find some extra features beyond just being a pair of headphones and a microphone.  These extras include a 3.5 mm auxiliary jack to connect external music and bluetooth to connect your phone or other device to the headset.  These typically come with circuitry to automatically mute or greatly decrease the volume of these inputs when ATC is transmitting.


Has anyone tested or flown permeable wings to increase efficiency?

Not really a great answer but:
Tested - yes I believe so.  Actively used - not to my knowledge/unsure.  The structural complexity of this is challenging, and the cost to benefit probably isn't compelling enough for "traditional" configuration aircraft.
You may find this of interest A History of Suction-Type Laminar-Flow Control with Emphasis on Flight Research or Aerodynamics of Permeable Membrane Wings


Does paragliding count towards total time?

In the U.S., you can count the time as aeronautical experience in your logbook. But, that aeronautical experience can not be used to satisfy the requirements of Title 14 of the Code of Federal Regulations Part 61 unless the paraglide, powered parachute, or other aircraft meets the following stipulations per Part 61.51:

(j) Aircraft requirements for logging flight time. For a person to log flight time, the time must be acquired in an aircraft that is identified as an aircraft under §61.5(b), and is—
(1) An aircraft of U.S. registry with either a standard or special airworthiness certificate;
(2) An aircraft of foreign registry with an airworthiness certificate that is approved by the aviation authority of a foreign country that is a Member State to the Convention on International Civil Aviation Organization;
(3) A military aircraft under the direct operational control of the U.S. Armed Forces; or
(4) A public aircraft under the direct operational control of a Federal, State, county, or municipal law enforcement agency, if the flight time was acquired by the pilot while engaged on an official law enforcement flight for a Federal, State, County, or Municipal law enforcement agency.

This would eliminate the use of any aircraft flown under Parts 103, 105, & 107.
One less expensive way of getting flight time would be to fly as a safety pilot for someone flying simulated IMC using view limiting devices. If you are instrument rated, you can fly as PIC while someone else is the sole manipulator of the controls of the aircraft in real IMC under IFR.


Differenciate- the motion of "Nose-up trim" and "Nose-down trim"

There are two pitch inputs* in the cockpit: the yoke and the trim wheel. The effects add up - you can achieve the same pitch up moment by the yoke only, the trim wheel only, or a combination of the two. The pitch up or pitch down motion of the airplane is always the sum of the two.

*That is not a very correct statement, but for now let's put things that way for easier understanding.

The difference between the yoke and the trim wheel is that once you let go of the yoke, it returns to neutral. However the trim wheel stays where it is.

So let's say you want 2 units of "pitch up force" (and let's ignore what the actual unit in physics is, it is just a number) in a certain flying situation. You pull on the yoke until you reach the desired pitch. Great. However if you let go of the yoke, you will loose that pitch up force and the aircraft will start to pitch down. That is not what we want - we want the airplane to hold this pitch attitude, stable, for the next 10 minutes. If we move the trim wheel from the neutral position to 0.5 units up, the desired amount of pulling on the yoke is reduced - we still need to pull back on the yoke, but not as much - we only need 1.5 units of pitch up on the yoke because the other 0.5 units is provided by the trim wheel. This is what "relieve back pressure" is referring to. If you move the trim wheel to 2 units up, you can now completely let go of the yoke, and the aircraft is stable.

  Is the motion in opposite of when pushed down, nose up trim and vice
  versa to that motion?

I think you might be confusing the pitch input with the movement of the trim tab on the elevator, assuming that your textbook mentions it. On most general aircrafts, a trim tab is used for pitch trim control. A trim tab is essentially "an elevator of the elevator". The elevator needs to move up for the airplane to pitch up. But the trim tab needs to move down for the airplane to pitch up.

Do not confuse how the trim is achieved aerodynamically, with what you input in the cockpit. The trim tab is just one of many ways to control pitch trim. Airliners, for example, do not have a trim tab. However, the principal of operating the trim wheel is the same. It is just a large aircraft uses a different method to hold a stable pitch attitude.


Can fuel be stored in the anti-shock bodies?

Yes, and there have been cases of this. Tip tanks of the period when aircraft flew already supersonic and jet engines were still very thirsty are a good example. Below you see the area-ruled tip tank of the F-5.

F-5 tip tank (picture source).

Now that @voretaq7 got me thinking, I should also mention the "Doppelreiter" fuel tanks (slipper fuel tanks) which were used on some German fighter airplanes in WW II. They were mounted above and behind the wing, and to everyones surprise they had little impact on the top speed of the airplanes, and in case of the Me-309 helped to increase it slightly. They were the first practical application of Küchemann carrots and worked much like the flap track fairings of today's airliners.

FW-190 A with Doppelreiter tanks.


What happens if a passenger passes through the boarding gate, but doesn't get on the aircraft?

Passengers are counted before the plane leaves the gate. Since everyone's boarding pass is scanned at the gate, they know how many passengers should be on board. If that number does not match, it may be a red flag that someone has sneaked out.

The missing passenger can usually be located as using the lavatory, changed seat etc. As a last resort, the passenger's luggage is removed from the cargo hold for security. If things get to that stage, the flight is inevitably delayed for sure.


Why shouldn’t the A330/40’s speedbrakes be used in alternate law?

The table in the report omits a condition. Here is the ECAM message in full:

The limitation applies when the aircraft is in emergency electrical configuration (run by the ram air turbine), which is one way to have the flight laws degraded.
The manual does not give a direct reason (not unheard of), but in fact there's more than one reason.

► As a quick summary, you lose 2/3 of the spoilers and the outer ailerons, and if more unlucky, you lose 5/6 of the spoilers.
If you happen to use the now-not-very-helpful spoilers, and you lose more hydraulic pressure, they'll get stuck in the up position (adding drag and degrading roll). So, DO NOT USE makes sense.

The how:

In emer elec config, the plane loses 3 of the 5 flight control computers; what remains are P1 and S1 (refer to diagram above).

The outer ailerons go into an unpowered state to conserve hydraulic fluid/pressure – the right aileron upfloats* like on the A320 (no P3 and S2).

If the planes loses G or Y hydraulic pressure, the plane is left with one panel on each wing, which is likely to be needed for roll control at slower speeds (the outer ailerons are already out).

The references (click to view):

All images are from the A340 FCOM, and color highlights are mine. Do not use for flight.
A330 vs A340
Thanks to @JZYL, note that there are some differences between the A330 and A340, while the A340 would announce MOST SPOILERS being INOP, the A330 would announce HALF SPOILERS (an extra computer remains powered). The same rationale given should apply though.
* This is also confirmed from this FCTM (smartcockpit.com) of an airline with both the A330 and A340 in its fleet (see PDF page 207):

(...) The AP will disengage when the failure occurs but AP 1 can be reengaged on the A333 if the EMER GEN is powered by an EDP. As there is no AP available in this configuration in the A340, the Captain must take control and fly the aircraft manually. The A340 aircraft is out of trim in roll due to right outboard aileron upfloat, caused by no power being available to Prim 3 or Sec 2, and neither pitch trim or rudder trim is available. (...)

Note: I haven't found a reason for the different architecture, but ETOPS is a possibility.


Does aircraft nacelle length/shape/geometry affect the contrail formation?

Ultimately the engine is dumping water into the atmosphere and this will quickly cool to ambient temperature.  Depending on the relative humidity at altitude it may or may not condense.  These factors are irrespective of the engine design provided that combustion is more or less complete, so the only factor that will significantly affect contrail formation is the extent to which the exhaust gases are distributed.  This will certainly be affected by the design but is hard to predict in general how; it’s mostly down to fluid dynamics well downstream of the engine itself.


What is the difference between an APU and an ATS?

The ATS is powered by the APU, so you typically need both. It's a bit different for some fighter jets though.

See: How is bleed air used to start a jet engine?

The battery is used to start the APU, the APU then provides electrical and pneumatic power.

The pneumatic power is used for air conditioning, engine starting, pressurizing the hydraulic reservoirs, and other things.

The ATS is a turbine that needs to spin, it is spun using this high pressure air from the APU. When the ATS spins, it spins a shaft connected to the engine, which then spins the engine just enough to compress air and start.


What is common number of flight hours a year for an airline pilot?

Flight hours are limited to 30 hours in 7 days, 100 hours in a month and 1000 in a year.  Scheduling rules also say I need at least 1 day off a week, so 6 day trips are the max for me (121 US domestic scheduled).

Let's look at a typical trip, which at my company tended to be a 4 day trip.  You want good productive trips, but you can't always get them.  On a 4 day trip let's say I have 6 hours of flight scheduled each day, or 24 hours scheduled that week.  I am getting paid the better of 24 hours or the actual flight time.  Now let's look at my duty day.  For a 6 hour day with 4 legs it was not unheard of to have a 12 hour duty day.  So now for a 4 day trip, I'm "at work" 48 hours and being paid for half of that.  Now consider that I'm not going home every night and my trip starts at 6 am on Friday and ends at midnight Monday night -- that totals to 90 hours away from home.

How does this compare to a 40 hour work week in an office?  In that case you are on duty 40 hours, getting paid 40 hours (or salary) and if you have a 1 hour commute one way, you are spending 50 hours away from home.

Back to the flight schedule.  A given month will have trips less productive than 24 hours and although you can probably build a 96 hour month if you tried, the average line of flying is typically going to be 75 hours of flying.  You can ballpark that will equate to 150 duty hours and 300 hours away from home for the month.

Extrapolate that to a year, and you have 900 flight hours, 1800 duty hours and 3600 hours away from home.  I would say this represents the average US domestic 121 pilot.  Some do more, some do less, but this is pretty typical.

What do we do with all of that duty time that isn't flying?  Let's see:

Eating
Updating charts
Checking the weather
Checking the paperwork
Coordinating with gate agents, ramp agents, fuel agents to make sure we leave on time
Programming the FMS and getting our IFR clearance
Preflighting the airplane
Postflighting the airplane
Doing the weight and balance
Sleeping

Note, that all of these activities require we are at the airport, in the secure area and we are not being paid.  The pay clock starts (roughly) when the airplane is buttoned up and the parking brake is released and ends when the parking brake is set and main cabin door opened.


Looks like the "Homebuilt Hornet, one-off wonder plane" on the cover of the March edition of the Australian Sport Pilot Magazine.

The article can be found on pages 34-37.


What are the regulations regarding plane spotting in the US?

Generally absent a specific prohibition you can take a photo of anything you can see with your eyes from public property (like a sidewalk). That includes airports, airplanes, bridges, tunnels, police officers, kittens, and unicorns.
(For more in-depth information check out Andrew Kantor's excellent article and Bert Krages' excellent one-page flyer on photographers' rights, or check out http://photography.stackexchange.com - they've covered airport photography, though not in any real depth, and I'm sure they have some street photographers well versed in the legal aspects of taking pictures.)

So what constitutes a "specific prohibition" on photography? Generally a clearly visible sign that says PHOTOGRAPHY PROHIBITED (the old Grumman facility in Bethpage had such signs on all of the fences where there was a decent view of the runway).

Absent such a clear prohibition you're free to take all the photos you want as long as you're on public property while you're doing it (i.e. "not trespassing on airport property"), but be aware that some law enforcement officials may not see it that way, and you may have to have some uncomfortable interactions with them.
In my experience most police officers are well versed in the law, though occasionally you'll find one who isn't. You're more likely to have trouble with a "rent-a-cop" security guard though.

If you want really good photographs (and you're not photographing at a major airport like JFK or O'Hare) you might want to speak to the airport management. At smaller airports someone - either airport personnel or a local pilot - might be able and willing to escort you airside where you can get some really great shots.
It helps in this situation if you have a body of work you can show (either published photos or art prints). The caveat is that many airports will also ask that you carry some kind of insurance while you're photographing on their property (and at larger airline fields that requirement can be substantial).


Did B-17 gunners beat on the wings of other planes in their formation?

That'd be a roughly 1 meter stick you've got to beat that other aircraft with, at most. Not a long stick at all.

By the time the other aircraft got that close a collision would be unavoidable. Not only would momentum carry them closer, but the banging would likely not even be heard by the crew of the other aircraft.

Remember they'd be wearing headphones, not just for the intercom but even more important for hearing protection. A B-17 is a LOUD aircraft when you're flying it.

Also, by the time you'd get that close the crews of both aircraft would have been screaming at their respective pilots for some time to ask them what the hell they're thinking getting that close to another aircraft.


How often do runways need to have typical maintenance?

The pavement requires frequent renewal of the top surface. The frequency depends on the type of pavement and on the weather. Asphalt for instance suffers a lot of damage when it snows and becomes less viscous when it is very hot, causing heavy aircraft to sink.

The main issue with repairing a runway on a major airport like JFK or O'Hare is doing so with little to no impact on traffic. Resurfacing an entire runway can take a long time. Therefore, rather than closing the runway for days at a time, airports try to do as many short maintenance operations as possible at night.
Some operations cannot be done in a single night but can be divided into several perfectly timed tasks, that can be done between 11 PM and 5 AM. Some operations can not be divided into such small tasks and require that the airport closes for a day or more.

The French airport Orly (ORY) for instance has one slab of concrete replaced every night on the runway. This way, the strip can be renewed every other year on average, without disturbing traffic. (I saw a video on this subject once, but can't seem to find it again.)

The results of each runway inspection are compared with the results of the previous runway inspection. Maintenance programs are revised based on the rate of deterioration of the runway. The FAA has various resources to help airport operators plan these maintenance operations.

But damage done by huge planes is only one of the many things that needs to be taken care of on a regular basis. Moreover, aircraft manufacturers try to design landing gear that reduces the impact of the aircraft on the runway as much as possible (note that airports can charge higher landing fees for aircraft that do more damage to the runway, so airlines want airplanes that don't damage the runway).
The most common maintenance operations are (not in any order, and indicated frequencies are only a rule of thumb, as these will change from one airport to another):

Removing rubber. This is an important one. When taking off or landing, aircraft often skid for a brief moment and leave rubber on the runway. This greatly reduces the adherence of the runway, which has a negative impact on stopping distances. This is usually done with high pressure water.
Cleaning the approach light systems and other visual aids. These get dirty with rubber, tartar, dirt... This operation can be done for instance with a mix of water and sodium bicarbonate, or by using dry ice.
Checking the quality of the approach light systems and other visual aids. Often, a truck with optometric sensors drives down the runway and measures the luminosity. Sometimes the lights need to be replaced. Airports usually have spares available for every type of light that is used on the runway.
Paint and markings somtimes have to be redone.
Evaluating the pavement and surveying the structural condition of the runway. Trucks are equipped with all kinds of sensors and go up and down the runway. The measures are used to make a map of the condition of the runway. Sometimes, the runway is divided into sub-sections and a different section will be evaluated every month or every other month, so that each section is inspected twice a year.
Checking for foreign objects on the runway. On all the airports I visited, this is done by the airport firetruck several times a day. Every few months, they sweep the runway to prevent grass, dirt, pebbles,... from accumulating.
Repairing cracks and resealing joints on the runway. This is to prevent water infiltrations that have long-term catastrophic consequences. A visual inspection of the runway is performed daily to look for cracks.
Cutting the grass around the runway and on the airfield. The grass has to be kept 2 to 4 inches high around the runway. This reduces the amount of debris that can be blown onto the runway. This also reduces the number of birds and other animals living close to the runway (because nobody wants birds to be ingested by an engine, or a squirrel to be run over).
Keeping all water evacuation paths clear. No water can be left to build up on the runway, since this would increase stopping distance for aircraft, and may freeze.

There also are seasonal operations, such as de-icing the runway or removing snow.


This seems to be the "Assedreme airport and seismic camp", according to Openstreetmap. Aviation Africa has a picture.

This is most likely a now disused airstrip for a base camp for seismic oil and gas exploration. Seismic exploration is a technique for searching for oil and gas deposits by measuring the reflection of artificial seismic waves (simple introduction at oilandgaslawyerblog.com).

The airstrip seems to have been built in 1985, expanded in 2008, and then abandoned. This fits pretty well with an article describing exploration in Mali, which states that lots of seismic exploration was carried out in Mali in the 70's and 80's, with renewed interest in the 2000's.

As J Walters pointed out in a comment Algerian exploration company ENAGEO mentions using this airstrip for its operations in a presentation from 2009.


Are student pilots required to have spin entry and recovery training?

US used to, I recall doing spin & recovery 3 times in a Cessna 150 Aerobat (in 1994), and feeling queasy for quite a while after that. I think now those maneuvers just need to be demonstrated. See AC 61-67C, excerpt follows

  CHAPTER 3. FLIGHT TRAINING: SPINS
  300. SPIN TRAINING. Spin training is required for flight instructor-airplane and flight instructor-glider applicants only. Upon completion of the training, the applicant’s logbook or training record should be endorsed by the flight instructor who provided the training. A sample endorsement of spin training for flight instructor applicants is available in the current edition of
  AC 61-65, Certification: Pilots and Flight and Ground Instructors.

  a. Spin training must be accomplished in an aircraft that is approved for spins. Before practicing intentional spins, the AFM or POH should be consulted for the proper entry and recovery techniques.

  b. The training should begin by practicing both power-on and power-off stalls to
  familiarize the applicant with the aircraft's stall characteristics. Spin avoidance, incipient spins, actual spin entry, spin, and spin recovery techniques should be practiced from an altitude above 3,500 feet AGL.

  c. Spin avoidance training should consist of stalls and maneuvering during slow flight using realistic distractions such as those listed in Chapter 2. Performance is considered unsatisfactory if it becomes necessary for the instructor to take control of the aircraft to avoid a fully developed spin.

  d. Incipient spins should be practiced to train the instructor applicant to recover from a student's poorly performed stall or unusual attitude that could lead to a spin. Configure the aircraft for a power-on or power-off stall, and continue to apply back elevator pressure. As the stall occurs, apply right or left rudder and allow the nose to yaw toward the stalled wing. Release the spin inducing controls and recover as the spin begins by applying opposite rudder and forward elevator pressure. The instructor should discuss control application in the recovery.

  e. Spin entry, spin, and spin recovery should be demonstrated by the instructor and repeated in both directions by the applicant.

  (1) Apply the entry procedure for a power-off stall. As the airplane approaches a stall,
  smoothly apply full rudder in the direction of desired spin rotation and continue to apply back elevator to the limit of travel. The ailerons should be neutral.

  (2) Allow the spin to develop, and be fully recovered no later than one full turn.
  Observe the airspeed indicator during the spin and subsequent recovery to ensure that it does not reach the red line (VNE).

  (3) Follow the recovery procedures recommended by the manufacturer in the AFM or
  POH. In most aircraft, spin recovery techniques consist of retarding power (if in a powered aircraft), applying opposite rudder to slow the rotation, neutralizing the ailerons, applying positive forward elevator movement to break the stall, neutralizing the rudder as the spinning stops, and returning to level flight.

  f. During spin training if a spin is not fully developed, the aircraft may instead go into a spiral. A spiral may be recognized by a rapidly increasing airspeed after the attempted spin entry. In an actual spin, the airspeed normally stabilizes below stall speed). The pilot must recognize a spiral and initiate immediate recovery to prevent exceeding structural limits of the airplane.

  SPIN TRAINING AND PARACHUTES. Title 14 CFR part 91, § 91.307(c) prohibits the
  pilot of a civil aircraft from executing any intentional maneuver that exceeds 60° of bank relative to the horizon, or exceeds 30° nose-up or nose-down attitude relative to the horizon, unless an approved parachute is worn by each occupant (other than a crewmember). Section 91.307(d) states, in part, that § 91.307(c) does not apply to flight tests for a Pilot Certificate or rating, or spins and other flight maneuvers required by the regulations, for any certificate or rating when
  given by a certificated flight instructor (CFI) or an airline transport pilot (ATP) instructing in accordance with part 61, § 61.167.

  a. Section 61.183(i) requires an applicant for a Flight Instructor Certificate airplane or glider rating to receive flight training in stall awareness, spin entry, spins, and spin recovery procedures. The applicant must also possess and demonstrate instructional proficiency in these areas to receive the certificate or rating.

  b. Because spin entry, spins, and spin recovery are required for a Flight Instructor Certificate airplane or glider rating, a person receiving instruction from an authorized instructor need not wear an approved parachute while instruction is being provided in these maneuvers.

  The instructor providing the training is also not required to wear an approved parachute while providing this flight training.


Is it possible to achieve torque equilibrium in order to fly?

If I understand the problem correctly, there will be a camera attached around the perimeter of the copter, which must have an uninterrupted view.

If the camera just swings around a perimeter, there will be two problems:

Trim of the device. There are only three rotors. If the device is in a trimmed hover and the camera swings around, the device needs to be re-trimmed rapidly to prevent roll/pitch.
Reaction yaw. The device starts spinning the other way that the camera is swinging.

Best way is to give the camera a fixed place and make the whole device spin, via gimballing the main rotors or using two vertical propellers. A counter-weight to the camera will put the CoG in the centre.


How airplanes of new generation communicate with ATC over remote areas? (North Atlantic Region)

Planes in the North Atlantic with the latest equipment as you ask would use VDL only within line-of-sight. Otherwise they would use satcom or HFDL (HF data link) for data comms.

(Click for full map) VHF coverage for FL 300, the lower the plane, the smaller the areas.

Data communications will be via CPDLC or ACARS. For voice communications there is also a satcom voice option. There is also ADS-C for tracking, which is mandatory for certain flight levels.

Pilot-to-pilot voice communications to relay information or during emergency is also available on 123.45 and 121.5.

Further reading and source: ICAO NORTH ATLANTIC OPERATIONS AND AIRSPACE MANUAL


How can static pressure be obtained over a range of airspeeds?

I used to have that misconception too.
It turns out, to get that pressure drop, you need to accelerate the air. On aircraft, this is done by changing its direction and causing it to flow around convex curvature. This occurs at the tail, on top of the wings, and often at subsonic speeds, on the nose just past the tip high pressure point, and beneath the wings. (Yes, subsonic flow is weird)
Freestream air flowing undisturbed past a flat surface will have the same static pressure - relative to the surface or absolute -, regardless of airspeed.


What materials are used to build a military runway?

I believe C-130 was designed to be operated from unprepared runways for takeoffs and landings. One of the reasons for India to buy it and deploy it to forward operating base.


Are aircraft engines classified as DAL A or DAL B?

DAL started in the software world with DO-178, but it has been extended to the entire development process.  This is documented in ARP4754A Guidelines For Development Of Civil Aircraft and Systems and ARP4761 Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment.

But to the direct question, 14 CFR 33.75 Safety Analysis, describes the safety levels required for the engine.  Matching the wording there

  (3) The applicant must show that hazardous engine effects are
  predicted to occur at a rate not in excess of that defined as
  extremely remote (probability range of 10−7 to 10−9 per engine flight
  hour).

with ARP4761, it is describing DAL B.  So I would have to agree with the speaker.

But I will offer one point of personal experience which is that one FAA certification officer insisted the DAL for the FADEC software should be DAL A.  The argument is that a common mode fault in the FADEC software could result in simultaneous loss of both engines.

One other fine point of certification is that complying with Part 33 allows you to get a Type Certificate for the engine.  That doesn't mean it meets all the requirements necessary to allow an aircraft with that engine installed receive an aircraft Type Certificate (under Parts 23 or 25).


What advantages are provided by an unstable canard configuration for fighters?

You want your control surface to create only little lift, so it has enough margin for maneuvering. This confirms your first guess.

Your second guess is also correct: Flying supersonically shifts the center of pressure back and increases stability. If the aircraft is unstable subsonically, it will suffer far lower trim losses supersonically.

Please read all about unstable designs in this answer. For conventional, stable configurations it makes most sense to put the control and damping surfaces at the back, and a canard is the better choice for unstable, highly maneuverable aircraft.


What is the thing in the middle of the turbofan?

egid is right. It is called spinner.

The spinner basically covers the part of the hub where the compressor blades are attached and reduces drag.

Source: b737.org.uk

It also serves other purposes:

Diverting the airflow efficiently in the center of the engine so that the airflow is smooth over the compressor blade hub

More importantly, the spinner serves to divert the rain and (more importantly) hail impinging on it towards the bypass fan and away from the 'core' of the engine, reducing chances of engine flameout.

The second point an important design parameter for the spinner. According to AGARD-AR-332, Recommended Practices for the Assessment of the Effects of
Atmospheric Water Ingestion on the Performance and Operability of Gas Turbine Engines,

  An effective way to remove a sizable amount
  of hail from the core is to optimize the spinner shape
  to deflect hail upon impact directly towards the fan
  duct.

The spinner of the CFM56 engine was modified in response to the engine flameout experienced in Garuda Indonesia Flight 421. The shape was changed into a conelliptical profile.


Why are there no large turboprop passenger airliners?

Large airliners don't fly at slower speeds.
It's simple economics.

If you have to connect two destinations 10,000 miles apart, you'll do maybe 2 round trips a week. Your passengers have no other choice, except a flight that takes even longer. You also have the luxury of flying between two very large cities.

If you have to connect two destinations 100 miles apart, you can do 3+ round trips a day. Your passengers choose and pick among a dozen other carriers that do the same, and many will just go by car or bus. And at this distance, at least one of the cities being services is small.

As a result, a single 50-passenger turboprop running a local route can transport as many passengers as a 500-passenger ultra-long-range turbofan. At the same time, the local route will have far fewer passengers per day.

Fast long-range turboprops are possible (see the Tu-95 and -114), and only a little slower than turbofans. But they're still louder. All in all, for large planes on long trips, both the flying public and people on the ground choose quieter faster planes over somewhat more fuel-efficient ones.

Extra noise for an hour is less of a pain, speed matters much less, and the smaller turboprops working these routes are less of a pain on the ground too. The fuel economy gap isn't all that large.


Is it permissible to log an instrument approach for purposes of IFR currency in a non-IFR certified aircraft?

As long as you remain VFR then the equipment requirements for the airplane and the flight are VFR.

§61.57 says “Within the 6 calendar months preceding the month of the flight, that person performed and logged at least the following tasks and iterations in an airplane, powered-lift, helicopter, or airship, as appropriate, for the instrument rating privileges to be maintained in actual weather conditions, or under simulated conditions using a view-limiting device…”.

It doesn’t say anything about having an IFR certified airplane or having a current pitot/static and altimeter check. If you are maintaining SEL IFR currency, then all you need is a SEL airplane. MEL IFR, then a multi-engine plane, etc. And if you are missing some of the 6-pack instruments, all the better for practicing partial panel.


What is the fundamental physics behind L/D decreasing as AoA increases beyond the optimal point?

The fundamental reason is that at high enough AoA, the lift becomes zero -- certainly no later than an AoA of 90°! At that point L/D is zero (there'll be lots of drag). So somewhere between 0° and 90° there will be an AoA with the highest L/D, and that is by definition the optimum AoA. Slightly beyond that angle there's nothing for the L/D to do except decrease, because if it didn't, the angle we're beyond wouldn't be the optimum.

Now if you were asking why that particular angle is optimal for a given airfoil, we would have to go into aerodynamics and boundary layers and whatnot. It's not merely about what happens to the molecules that (try to) hit the underside of the wing, but at least as much about how well the molecules above the wing can be convinced not to hit it.

Note that above the optimal AoA, until the critical (stall) angle, the lift generated still increases with increasing AoA -- it's just that in this range drag increases faster than the lift does.


How do aircraft go off-course even with all their guidance technology?

1) Technology is fallible.

2) Humans are fallible.

Now that aircraft have GPS receivers it is rare for them to be off course by a considerable margin. That said, technology can fail and there are cases where the GPS cannot, or should not, be used.

The crew can also make mistakes, either by incorrectly reading the navigation data or by incorrectly entering flight path details into the navigation system: An aircraft may actually be 'on course' based on what the crew told it to do, but they told it the wrong thing. Depending on how data is entered into the system it's easy to add the wrong waypoint (some have very similar names, there's been a few cases of that happening) or to enter reciprocal bearings or lat/lon points.
On top of that there's simple crew distraction - if they're manually flying then they may be focussing on something else and not notice that are off-course: As happened on the Sukhoi superjet demonstration flight a few years ago.


What are the rules of thumb for intercepting and tracking VOR and LOC courses?

the rule of thumb for IFR flying, including intercepting VOR and LOC courses, is the 5Ts:

Throttle: turn the throttle to initiate a climb or descent
Turn: to the new inbound or outbound heading
Time: reset the timer to time the
new leg
Twist: the OBS to the new course you're intercepting
Talk:
if you are at a reporting point, you should now use the radio


What is causing these "corners" on this F-104 V-n diagram?

what is causing the "corners" that we see at the following points?

Compressibility. Close to Mach 1 the lift curve slope increases according to the Prandtl-Glauert rule with the factor $\frac{1}{\sqrt{1-Ma^2}}$. Since the X-axis shows indicated speed, the Mach 1 point moves left with increasing altitude. Technically, those corners should also be added for the negative lift limit.

Do these points simply represent the "corners" of what performance is possible while still maintaining horizontal flight?

No. A v-n-diagram covers the whole load factor range while horizontal, steady flight happens along the line y = 1g (except for turns or inverted flight, of course). Adding more thrust will not change the limits. Maneuvering is only possible/permitted (see below) inside the lines and maneuvering  at constant altitude depends on thrust which is not included here. The lines show lift and structural limits; thrust envelopes look different.

Wouldn't it be theoretically possible for a pilot to operate well outside this envelope?

Not really. Momentarily yes, for example the stall lift coefficient moves up with higher pitch rate, but that only works while pitch angle is increasing. Also, at supersonic speed (after all, your example of 340 KIAS @ 40 kft is equivalent to Mach 1.07) the envelope is limited by angle of attack, not lift. Therefore, 4g at Mach 1.07 in 40 kft is outside of the permissible flight envelope but may be reached if the pilot overrides stick shaker and stick pusher (depending on control authority).

So this diagram is really as much about achievable performance as about protecting the aircraft from excess loading?

Yes. The region left of the stall lines is impossible to fly since lift is limited at lower speed. However, the top speed limit might well be exceeded in a dive if the pilot chooses to do so. Equally, the g limit might be exceeded right of the point where the envelope becomes horizontal.
Thank you @JanHudec for pointing out correctly that those areas which can physically be reached by improper flying but might incur damage to the airframe are colored red.


What is this partially disassembled aircraft in the desert?

So, you found what looks like an F-8 missing a wing in the middle of the USN's Air Warfare Center at China Lake.

It resembles the F-8 a lot:

Image Source

As @Andrew said in a comment, the plane might be an F-11 which has a little closer resemblance to your picture.

Image Source


Why would an ILS installation need a “reflecting surface” around the glideslope antenna?

Source: FAA 6750.16E - Siting Criteria for Instrument Landing Systems

The more common G/S antenna type works by reflecting the signal off flat ground, called "image type".

A non-image type was not available in the 70s as it's a mid-90s invention (patent; IEEE).


How can I calculate the effect of winglets on aircraft performance?

Basically, there are two ways. One is easy but imprecise, and the other is hard but more precise.

First the easy one: Look at other aircraft and estimate how much winglets affect lift and drag. Make sure to do this at several lift coefficients; winglets help much more at high lift coefficients. Don't forget to account for the added mass of the winglets and their added friction over their surface area. Bonus points for estimating losses due to sideslip.

The hard way is to do a numerical simulation of the wing. Since you want to know what difference the winglets make, you can focus on a comparison between a regular and a winglet-equipped wing and transfer the effect to the full airplane. For the lift and induced drag effects, you will at least need to divide the wing into panels and simultaneously solve the Biot-Savart equations for bound vortices at the quarter chord of each panel plus the trailing free vortices with control points at the three-quarter point where local flow must be parallel with local wing inclination. Make sure you use a method which does better than to assume that all panels lie in one plane!

I have no experience with Simulink - I guess there are libraries around for vortex lattice or even Euler codes, but if you are free to choose your tools, maybe it is worth to take a look at XFLR5. This should work out of the box for your project, and all you need to add is a proper input file.


Do reduction drives increase tach time quicker than direct drive engines?

The relationship between tach time and RPM varies based on the engine. As mentioned in the linked answer, it is difficult to find this relationship based on engine specifications, but if you find a tachometer certified for the engine it will have the correct ratio built in.
If the 912ULS needed TBO based on tach times, the tachometer would likely count tach time at 1:1 somewhere below 5500 RPM, since that is the maximum continuous speed for this engine. However, Rotax actually uses Hobbs time to determine when an engine needs a TBO, and specifically notes that a "mechanical hour meter" may give different times. Therefore, the TBO of 2000 hours is 2000 hours of real-world time.
From the 912 Series Maintenance Manual: (p. 3)

All of the maintenance intervals, such as the 100 hr. inspection and the engine TBO, relate to the number of operating hours of the engine.
The operating hours are defined as follows in order to prevent misunderstandings and to ensure safety:

All time during which the engine is running is counted towards the total number of operating hours.

The time is counted irrespective of the load factor of the engine, such as idling or take-off power.

NOTES: A mechanical hour meter is directly coupled to the engine speed, the readings may deviate considerably from those given by electronic remitters (e.g. TCU, FlyDat). Maintenance and overhaul intervals are always dictated by the readings of the electronic hour meter.


How does a coaxial rotor helicopter achieve yaw?

In a conventional helicopter the lift generated by the rotor is controlled by the collective pitch. Raising the collective pitch increases the Angle of Attack of the the rotor blades and consequently the lift, and inevitably increases drag. The drag is overcome by increasing the torque from the engine. Vertical movement is achieved by balancing the collective pitch against the torque while maintaining a relatively constant rotor speed.

The torque from the engine pushing the rotor one way results in a tendency of the fuselage to rotate in the opposite direction. This is conventionally countered by a tail rotor or other similar device, and varying the force generated by this rotor controls the yaw.

So far, so good.

In a helicopter with coaxial rotors there is no tail rotor, but the torque issue remains. Here, it's resolved by applying equal but opposite torque to each rotor.

Lift overall is controlled by changing the Angle of Attack of both rotors. If the same inputs are applied to both rotors then the torque remains balanced.

However, the Angle of Attack of one rotor can be increased while that Angle of Attack of the second is decreased, leaving lift overall unchanged. This will increase the drag on the first rotor, and hence the torque required to maintain rotor speed.

Simultaneously, the lift, drag and torque on the second rotor has been reduced, producing an imbalance in the direction of torque between the two rotors, and a consequent yaw moment around the axis of rotation.

All this can be achieved without a significant change in rotor speed. In fact, the exact rotor speed doesn't play a part in yaw control.


How does an aircraft descend without its nose pointing down?

A plane descends when it does not have enough thrust to maintain its altitude. A plane can descend with its nose pointed up or down so long as there is not enough thrust to maintain altitude. Altering the pitch of an aircraft is used to control airspeed: pitching up slows an aircraft down (and may cause a climb if done from a level attitude) and pitching down generally speeds up an aircraft (and causes a descent if done from a level attitude). So if you want to descend at a slow speed you reduce power and pitch the nose up.

Since you want to land at a slow speed you will need to pitch up and slow the aircraft down while reducing power to descend nicely. This article covers it nicely in terms of flying an approach. It's also covered in this question.


What does 'EST' at the end of a NOTAM's valid time mean?

If the NOTAM duration is expected to return to service prior to the
End of Validity time, the time is expressed by using a date-time group
followed immediately by EST (estimate).  Any NOTAM that includes an
EST must be canceled or replaced before the NOTAM reaches its  End of
Validity time. If the NOTAM is not canceled or replaced, it will
expire at the end  of validity time regardless of EST.

Reference:
https://www.faa.gov/documentlibrary/media/order/notam.pdf#page=7


You can, but the accuracy is going to be somewhat poor.

Given the positions you can approximate the path with your favourite line approximation method. The important thing is that it can give you continuous evaluations (no jumps and no discontinuities) of at least the first and second derivative. Third order algebraic splines are a good approach.

Note that you will need to map Latitude and Longitude to some Cartesian representation. Depending on the length of the flight, a "flat earth" approximation might or might not be a good idea.

With these, assuming that each manoeuvre was mostly flat(*), you can compute your local curvature:

$$k = \frac{x'y'' - y'x''}{\sqrt{(x'^2 + y'^2)^3}}$$

Now you can estimate your bank angle $\phi$ with

$$\phi = atan\left( \frac{k \cdot V_{tas}^2}{g} \right)$$

where $g$ is Earth's gravity.

(*) the formula is for a manoeuvre in the x-y plane. You could turn your coordinates so to have a local x-y plane that is coincident with the plane where the aircraft was manoeuvering, but then you could not use the bank angle formula, that is correct only for turns in the horizontal plane (thanks Jan Hudec for correcting)


Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?

You can find the full incident report here and this topic is touched upon briefly, but in short they had little to no time to entertain any other options but a full speed landing.

  It was not until the aircraft [was] on the final descent for landing that
  the Commander realised they could not reduce the thrust on the number
  1 engine. The speed was not controllable and from that point, there
  was no time for the crew to consider other strategy nor procedure to
  cope with such emergency situation.

and more in the conclusion section...

  t. At that stage, there was no time for the flight crew to consider other
  strategy nor procedure to cope with such emergency situation. The
  flight crew concentrated on flying the aircraft for a safe landing.

First off, the engine was throwing errors throughout the flight and they were talking to the maintenance team at other points. Ultimately, the proper steps were taken and everything was done by the book. They were prepared for an engine-out landing. When you have a runaway engine malfunction (or throttle stuck at full) shutting down prior to landing may not be the right decision if the running engine provides no immediate safety risk. If you shut down a problematic engine in flight you run the serious risk of not being able to get it started again.

Considering that most airports have a bit (or a lot) of extra runway, EMAS systems and often land at the end of the runway, coming in overspeed and burning through your tires and brakes may be safer than cutting the engine and potentially falling short of the runway.


What if pilot feels too tired before his flight?

So if you are well rested and not ill, but still feeling tired, there has to be something else wrong. From your description, it appears to be fatigue. The common signs for fatigue are:

Falling asleep
Yawning
Poor visual acuity
Feeling "sluggish" or "drowsy"
Decreased reaction time
Decreased concentration

Although, the most commonly known reason for fatigue is lack of sleep, but any or all of the following can cause fatigue:

Lack of quality sleep
Sleep disturbances
Interruption of circadian rhythm
Mental or emotional stress
Physical exertion, such as heavy exercise
Poor health, including dehydration or poor diet

Pilots can assess their own fitness to fly by the IMSAFE mnemonic. FAA has a small handout about fatigue.

Now what pilots (and generalizing, people) can do and actually do are two very different aspects. A survey about European pilots mention:

  ... many are afraid their fatigue reports could have negative
  consequences for their professional future (i.e. reprisals by
  management) ...

FAA has a new rule which states:

  The FAA expects pilots and airlines to take joint responsibility when
  considering if a pilot is fit for duty, including fatigue resulting
  from pre-duty activities such as commuting.  At the beginning of each
  flight segment, a pilot is required to affirmatively state his or her
  fitness for duty.  If a pilot reports he or she is fatigued and unfit
  for duty, the airline must remove that pilot from duty immediately.

The answer to your question is: Yes, they can!


Can you help me identifying this circa 1910 airplane with tail number 72?

It is a Wright, allright, but more probably an EX. The EX was a modified Model R, which in turn was a modification of the Model B. The R and the EX were single seaters, whereas the B would seat two.

Picture of a Model B replica, as taken from its Wikipedia article:

Picture of a Model EX, taken from this site.

The EX was the model used by Cal Rodgers for his epic transcontinental flight. Note the lengthened tail and the closer wings, which allowed to reduce rigging wire and, thus, drag. The "72" shows the same features, so I think it is a Wright Model EX.


How can business jets use slot coordinated airports?

Depends on the particular airport, but I will take The Netherlands (Which has three slot-coördinated airports, including EHAM, EHRD and EHEH) as an example here.

According to the ACNL all flights to and from a coordinated airport can only be executed when an air carrier or any other aircraft operator has been allocated an airport slot. According to Article 2, paragraph g, of the Regulation as state flights, emergency landings and humanitarian flights are exempted. General aviation is therefore subject to slot coordination (at EHAM and EHRD). However, according to the LOC GA AMS, helicopter and GA propeller-driven aircraft under 5700kg MTOW are exempted from the slot system.

In conclusion: Regulations depends on country and airport. You should carefully read them before starting your flight to and/or from a coordinated airport.

A detailed PDF on how to request a slot can be found here.

GA slots for Europe can be requested through e-Airportslots


Principle of aerodynamic lift: are misconceptions also taught in flight schools?

I am a CFI who teaches at a large (+200 students) flight school in the United States.  You might be surprised to hear this, but...
We really don't worry about how a wing works that much.
As far as I'm concerned, the technical explanation for how a wing works is a subject for the engineers who build and design such things.  Private pilot applicants (at least all of the ones that I have met) are more concerned with things like "How do I get the plane into the air??" and "What do I do if it starts coming back down again in a hurry?"
In fact, Van Sickle's Modern Airmanship starts off the chapter on aerodynamics by saying (paraphrased):

Some of the concepts presented in this chapter are wrong, but they are useful illustrations.

So, to answer your question, we teach that:

The alignment of the wing to the relative wind displaces air downward, which creates lift.
Because of the shape of the airfoil, air on top of the wing has a lower pressure than air below the wing, which also causes lift.

And unless a student asks us for more information, we leave it at that.
If you hope to become an aircraft designer or research fluid dynamics, you'll quickly be corrected of any misconceptions you may have about Mr. Bernoulli and his asymmetric wing.  Most student pilots, however, are satisfied with a pre-discussion "What we'll talk about today isn't technically correct, but you'll find it a lot easier to understand the necessary concepts this way."

Peter Kämpf made a worthwhile comment:

It is really not so hard to understand aerodynamics correctly, and you
make it sound as if you prefer a short term gain over a profound basis
which could help pilots to really understand what happens with their
plane and to select the most appropriate action.

Which is very true - it's not difficult to understand aerodynamics correctly.  I'll defend my viewpoint with an analogy:  Consider a store where you are shopping with a child who doesn't yet understand decimal addition.  You have two purchases, one costing $5.08 and one costing $3.99.  The child adds the big numbers and tells you that the final price will be $8. You now have (at least) two choices: you could begin a discussion of significant figures and fractional multiplication (can't forget tax!), or you could praise the child for applying the skills they do have and getting an answer which is pretty close.
Is it better if the child eventually understands how to calculate tax rather than simply trusting what the cashier reads off the screen?  Of course.  But at the stage where most of my students are, it's much more valuable to their development as pilots to simply praise them for being close enough.
As regards JAL123, I am in 100% agreement with you.  By the time you as a pilot have progressed sufficiently in your development to be flying something with a turbine pushing it, you should certainly know the principles and concepts of your machine to the highest degree of accuracy.


What happens if I am flying at a higher Lift/Drag ratio than required?

If your optimal lift coefficient for long range cruise flight is greater than what you need, you are flying too fast, or too low.
For cruise flight, your lift needs to equal the weight, otherwise the aircraft will accelerate upwards (in the body frame of reference).
If you know the lift coefficient that is optimal for cruise, you need to adjust the airspeed and density (altitude) to make sure that the resulting lift equals the weight.
$W = L = \frac{1}{2}\rho V^2 C_L S $
$\rho V^2 = \frac{2 W}{C_LS}$
Reduce speed and/or increase altitude until the lift and weight are equal at the optimal lift coefficient. That will give you the maximum range.


Why do TACANs not have a symbol for compulsory reporting on IFR Enroute Low Altitude charts?

TACANs are for military use. VOR or VORTAC are the civilian equivalent.  Civilians can't generally tune in TACAN.

This wikipedia article has more details.  https://en.wikipedia.org/wiki/Tactical_air_navigation_system


Which airplane designs have the greatest longevity?

This is a community-wiki mashup of the other answers - I thought a table would be useful.

Date Introduced
Aircraft Type
Commercial Service (2015)

1909
Bleriot XI
Flown by Shuttleworth collection UK, entrance fee.

1932
JU-52
Sight seeing flights by Ju-Air, Switzerland.

1932
Tiger Moth
Flight experiences, e.g. Cheltenham UK.

1934
Dragon Rapide
Sight seeing flights, London.

1935
DC-3
Many commercial flight-experience/other operators.

1935
PBY Catalina
Still used in aerial firefighting role.

1938
Piper Cub
Many still in private/GA use and in flight schools.

1947
AN-2
Still in widespread use in 2020.

1952
B-52
76 still in service with USAF. Projected service to 2045?

1952
Tu-95
In service with Russian air force. Projected service to 2040?


How to find the remaining fuel without electrical power on the MD-80?

The normal Digital Fuel Quantity Display in the flight deck does not work without AC power, meaning you need to have either the APU running or external AC power connected:

  Fuel Tank Quantity Indicating

  A standardized modular fuel gauging system is used which requires no
  adjustment or calibration after system installation or component replacement.

  The Digital Fuel Quantity Display is located on the center instrument panel
  to indicate the quantity of the three tanks and gross weight. Operation of this
  display requires normal AC power.

(MD-80 FCOM Sec. 13 - Fuel)

The Fuel Load Display Panel on the right wing however can be powered via the battery:

  Fueling POWER Switch

  OFF - Removes power from fuel load selector display panel and fuel fill valve switches.

  ON - Supplies power from battery or external power to fuel load selector display panel and fuel fill valve switches.

(MD-80 FCOM Sec. 13 - Fuel - Controls and Indicators)

You can read off the current fuel levels in the upper row of the display panel:

(image source: MD-80 FCOM Sec. 13 - Fuel - Controls and Indicators)

Without battery power, manual measurements of fuel tank quantities are still possible with a magnastick:

  Fueling and Defueling

  [...]

  All fueling operations can be accomplished with airplane or externally
  supplied electrical power. If electrical power is not available for fueling
  operations, all fuel tank valves can be manually operated and fuel quantity
  measured using magnasticks.

(MD-80 FCOM Sec. 13 - Fuel)

The following section from a Dash-8 manual describes how the magnastick (or magnetic dipstick) works:

(image source: Dash-8 Q400 FCOM)

  Magnetic Dipstick Magnet
  Float Magnet
  Fuel Level in Main Tank
  Calibrated Magnetic Dipstick

  the magnetic dipsticks give an alternate means to measure the fuel quantity when the aircraft is on the ground
  the magnetic dipstick is accessed at the bottom of the wing
  when the rod is released, it moves slowly down until the rod magnet is attracted by the float magnet

(Dash-8 Q400 FCOM - Fuel)

  Magnasticks

  Two magnetic dipsticks (magna sticks) in each tank provide an alternate means of measuring fuel quantity when on the ground. Each consists of a calibrated rod, which slides within a tube extending vertically from the bottom of the fuel tank. When the rod is released, allow it to fall slowly until resistance is felt as the rod magnet becomes attracted to the float magnet. Read the tank contents from the bottom of the rod in U.S. gallons or in litres.

(Dash-8-200-300 FCOM - Fuel)


While Him's answer is correct, part of the reason that there aren't many airways over central China is just that there's rarely a reason to fly there. Where possible, aircraft prefer to take paths along great arcs, which are the shortest distance between two points on the surface of a sphere (such as Earth.)

In short, there simply aren't many common air routes between city pairs where the shortest path passes over central China. If you look at the first image posted in the question, you will see that the flights into China are primarily flying either to or from Europe or Eastern North America (the ones crossing over Mongolia,) Japan or Western North America (the ones crossing over the Sea of Japan and East China Sea,) India (the ones flying over South China,) the Middle East (the ones flying over North China,) or Australia/Philippines/Thailand/Indonesia/Oceania/etc. (the ones coming in from the South.)

For your great arc path to pass over Central China, you'd need to be going to or from central China itself (which isn't terribly populated,) Siberia (which is even less populated,) the Central Indian Ocean (which is open ocean with Antarctica on the other side,) or the mountainous region between China and India (which also doesn't have a lot of air traffic.) So, there's normally just not much reason to fly there and, thus, not much reason for China to have airways there.

For the specific example that was shown in the question of the Emirates flight, the arc on which its flight path is shown across Northern China is, in fact, very close to the great arc between Dubai and Incheon, which looks like this:

Great Circle Path from DXB-ICN Source: gcmap.com

This map should give you something of an idea for how unpopulated Western China is:

China, as seen on Google Maps Source: Google Maps


Your previous education does not matter that much, it's way more about your suitability for the extremely demanding job of professional pilot.

You can enter a range of differing training paths that lead, should you successfully complete the hard training, to an atp licence.

The ones that offer some kind of promise of getting hired, have rigorous selection processes.

Any training towards professional pilot license is ridiculously expensive, you'll have to consider that. It'll be years before it pays back financially.

Only you can be the judge of whether or not to pursue this, but a word of advice, if I may: it's a job, just like any else. It's really about how well you fit the job and vice versa. If you must become a pilot, you will.


What does dashed blue lines overlay with thick faded blue lines mean in an aeronautical-chart?

Overall: Turkey system may be specific

Turkey is not integrated in the Single European Sky. The harmonization and simplification of airspace classification going on in many European countries is not applicable to Turkey, so we are in a kind of specific case which requires more research effort to understand it. See this Eurocontrol report.

From the documentation I happen to read, the Turkish airspace system is seemingly as efficient as another and, for instance, is more efficient in releasing military areas (SUA) to civil use when possible.

I wasn't able to find any description. If you can register to the Turkey AIP, you should have access to the relevant data.

Additional information from ICAO GIS Viewer

The same area than the one in the question in the ICAO viewer. I have selected different layers (a bit of learning would be needed to understand all of them), and highlighted data for three areas:

I selected only the lower space, else the viewer display is really cluttered because the developers haven't done a great job in managing label locations. The areas are:

Yellow: ANKARA ACC SCTR 8 LOWER. GND to FL325.
Blue:  ESENBOGA CTLZ. SFC to 4,500 AMSL
Green: AKINCI CTLZ. SFC to 12,000 AMSL

You can click on an area and a list of descriptions is displayed. You can browse this list with the arrows on the popup title bar (multiple areas may be relevant for the point you clicked). For AKINCI CTLZ:

Which class of airspace are they? Which rules are associated with them? I've really no idea and the legend in the viewer doesn't help:

Special use airspace (SUA)

I think it's still reasonable to interpret for non-professional purposes the area names this way (LT being the ICAO prefix for Turkey):

LTD: Danger (e.g. LDT-20)
LTR: Restricted or Regulated (e.g. LTR-30)
LTP: Prohibited (e.g. LTP-0097)
LTM: Military (e.g. LTM-LTANKZ1).

So these are SUA.

Documents that may be interesting

ATC Prosedür ve Operasyonları Kılavuzu from IVAO Turkey.

Get additional help

You may also want to look at PPRuNE which is a discussion board for pilots. You'll find pilots flying in/to Turkey, and they may provide you more information.


How do pilots estimate glideslope visually without PAPIs?

There's no instrument you need for a good approach angle in good weather, it's all done by eye. When you train as a pilot you develop a sight picture of what a good approach looks like, and you develop a sense of what a runway looks like when you get too low or too high. It comes from experience and practice combining with the human brain's excellent spatial processing capabilities.


What is the effect of moving the centre of gravity ahead or behind the aerodynamic centre for HALE UAVs?

Glider pilots in a competition will try to place the center of gravity at the most rearward position possible, sometimes even further back than permitted. This will make the glider statically unstable, but the performance will not be much improved - this is more psychological than real. Don't discount psychology in competitions: Pilots who feel that they fly an inferior plane will take bigger risks to get ahead and have a much higher chance of spoiling their chances by doing something stupid. Therefore, everyone tries to tweak their plane, even if the tweaking only helps to give a good feeling.

Now to the physics: If the center of gravity (CG) is right above or below the aerodynamic center (AC), the aircraft's longitudinal static stability is indifferent. Move it forward and stability increases, move it further back and the plane becomes unstable. The aerodynamic center is where the angle-of-atttack-dependent lift forces act, and in an indifferent configuration the lift coefficient on wing and tail will be equal. Since the aspect ratio of the wing is normally larger than that of the tail, an indifferent configuration will already produce slightly more induced drag for the same lift than a slightly stable configuration. Details depend on the lift loss at the center of the wing due to the fuselage and the combined vorticity of wing and tail, but as a first approximation the above is valid. Moving the CG further aft only makes matters worse.

Now it can be argued that the rear CG location helps in maneuvering the aircraft. This might even be helpful with gliders, since they need to maneuver quickly into the center of a thermal, but HALE (high altitude long endurance) UAVs fly mostly straight, so maneuvers will be few, slow and deliberate.

In essence, moving the CG back in a very stable configuration helps, but the optimum is reached already before the CG reaches the AC. Moving it back even further is detrimental to performance and runs the risk of stalling the tail first due to its high loading.

I do not know of any HALE which flies in a statically unstable configuration, and the glider pilots who do will not openly talk about it.

The only application of static instability (CG behind AC) which boosts performance can be found in supersonic aircraft. And the performance improvement is most pronounced in supersonic flight because it reduces the losses from stability of a highly stable configuration. When incorporated from the start, subsonic instability enables the aircraft to use smaller wing and tail surfaces because both will work less against each other at supersonic speed.


Is it safe to fly on airplane with lithium batteries in cargo hold?

No, it is not safe to fly on an aircraft that has lithium-ion batteries in the hold.  There is a commentary on FAA Safety Alert for Operators (SAFO) 10017 here, which was issued after the crash of UPS Flight 6.

Admittedly, this was a bulk load of 81,000 batteries on a cargo flight.  However a search for 'battery' on AV Herald shows between one and two incidents each month, of lithium ion batteries/devices igniting in the cabin.  These are only the ones reported on that website, we don't know how many may go unreported

The ICAO also considers Li-ion batteries a risk but as Simon Hradecky points out, there is a conflict between this safety advice and the security requirements that force passengers to check-in laptops, tablets etc on some flights.

Personally, I think that, whatever the ICAO, FAA and airline requirements, there are going to be some of these devices that get into the hold (people will forget that they left a battery bank in a bag and security will not recognise it on the scanner). We know that they regularly catch fire.  There are almost certainly going to be airliners brought down by this, it may have already happened - the EgyptAir MS804 fire hasn't been explained yet.


Can a helicopter really fly with rotors going this slow?

It's an illusion that the blades appear to be going slowly. It's actually a well known effect called the wagon wheel effect.

Essentially the rotor is spinning at close to an even multiple of the camera's framerate divided by the number of rotors.

This means that between frames the blades have moved a full quarter rotation (or a multiple of that). Creating the illusion that the rotor is moving more slowly that it actually is.


What are these silver stripes on Cosmic Girl for?

It's aluminum "speed tape" being used to run wires around the outside of the fuselage, possibly for load cells or some other kind of sensor related to whatever is being tested and that was impractical to run internally.  If you zoom in the image and look carefully at the vertical strip to the right and below TEST, you can make out a dark line in the middle of the tape that is a shadow from the wire bulging out.  Strictly temporary.

It looks like two window panels have had their acrylic panes removed and replaced with aluminum blanking plates with holes for passing the wire out through the pressure hull, making it a simple job to return to the normal configuration.


Is it better to reduce drag or increase lift?

Your lift will be prescribed and cannot be freely chosen. So what you need to do is to minimize the drag that goes with this given lift.
In straight flight lift needs to equal weight. In turns, the centripetal force is added to this. At high speed a small angle of attack will produce that lift while at low speed the angle of attack needs to be high. In most cases, takeoff and landing requirements will determine minimum wing size and the maximum lift coefficient of the airplane. In order to not drag around massively oversized wings, most airplanes use flaps to have a decent maximum lift coefficient for takeoff and landing while minimizing their wetted surface at high speed in order to keep drag down.


Can noise from the passenger cabin be picked up by the cockpit voice recorder?

It depends a bit. One of the microphones for the cockpit voice recorder is an "area microphone," which is designed to record whatever someone standing in the cockpit would hear (the others record from crew headsets and possibly the PA system). This area mic is continuously recording; it does not just turn on when there's more than some threshold of noise. If the noise in the cabin is loud enough to have been heard in the cockpit, it will be heard on that mic. If not, it won't.


Do Jabiru aircraft have a long history of engine failures or other technical issues?

I don't know about a "long history", but the Australian aviation authorities (Jabiru is an Australian company) did introduce operating restrictions because of what they considered to be a high rate of engine failures. Note that Jabiru makes their own engines, unlike most other aircraft manufacturers, and as well as using them in their own aircraft they sell them for use in LSAs.

CASA mentioned 45 incidents in one year:

  These precautionary limitations follow a high number of Jabiru engine
  failures and power loss incidents, some of which resulted in aircraft
  forced landings.

  More than 45 Jabiru engine failures or in-flight engine incidents have
  been reported in 2014, with CASA recently becoming aware of incidents
  in previous years.

  Problems with Jabiru engines include failures of through bolts,
  flywheel bolts and valve train assemblies, as well as cylinder
  cracking.

  The failures affect a range of Jabiru engine models and have occurred
  in aircraft used in different flying activities, although many have
  been reported in aircraft used for flying training.

By itself, the number 45 doesn't mean much without considering more information about the number of aircraft, the number of hours flown, maintenance performed etc. and Wikipedia says that Jabiru didn't agree with CASA's decision (which isn't surprising). But presumably CASA did think about those things and still decided that there should be restrictions in place.


Is the freestream dynamic pressure higher during cruise or during landing/takeoff?

Here is what I am getting:

Static pressure:
Sea level: 101300 Pa
30,000 feet: 30100 Pa

Mach:
Sea level1 (150 kt): 0.22
Cruise2: 0.85

Ratio of specific heats: 1.4

Using the equation:
Landing: $3432.044 Pa = 73.68 lbf/ft^2$
Cruise: $15223.075 Pa = 317.94 lbf/ft^2$

So the high Mach in cruise more than compensates for the lower static pressure. This calculator agrees.

1Landing speeds for large jets are generally between 120-150 knots (Mach 0.18-0.22). Smaller planes around 60 knots (Mach 0.091). You can convert to Mach by hand or using a calculator like here.

2Cruise speeds are generally between 240-280 kias (knots indicated airspeed) for large jets, which translates to around 450-500 knots ground speed and Mach 0.75-0.85 (depending on altitude and conditions).


The two configurations of A350 have different capacity.

A350-900: 138,000 liters / 36,456 US gallons
A350-1000: 156,000 liters / 41,212 US gallons

The tanks are shown in this picture:

Source


The appearance of being closed/open is a light trick; light reflecting off the tiny transparent window of the missile launch detector.

This detector typically sees in IR and would detect the plume of a heat-seeking missile. According to Wikipedia, the model used on the F-22 is AN/AAR-56 (IR based). (There are videos available on YouTube for its output; example.)

In the below cutaway, it's label number 7. Note it says windows, so I suppose there's more than one for the different angles (after some eye strain I couldn't find another 7).

Source: pinterest.com

The F-35 uses the AN/AAQ-37, below are the various locations:

Source: daumcdn.net (Korean)


Why does the F-15 have a swept-back trailing edge at its wing tips?

The F-15 wingtip is a "raked" tip configuration, which increases lift and decreases drag.1
[]2

This is the design decided by the USAF after discovery of several design deficiencies during initial flight test which included aeroelastic deficiencies (wing bending) and aerodynamic effects (buffeting). "In early June 1974, the Air Force flew the “raked” tip configuration and were completely satisfied
with the configuration’s buffet characteristics."  The Saga of the F-15 Wingtip


Is it ever permissible to takeoff on an aircraft heavier than its MTOW?

The crew took 3 tonnes of taxi fuel of which they only burned 800kg and that put them at least a tonne above MTOW not taking the tailwind into consideration which the report states would have been negligible.

I can't speak to operations in today's environment, but at the two 747 carriers I worked for in the late 1980s and the 1990s, it was quite common to load more taxi fuel that you knew you would actually burn prior to takeoff. This was especially true for the 747-100, which had only a four bay center tank as opposed to the -200 which had a five bay center tank. Justification was easy. For example, if you were taxiing out at JFK to a trip to Tel Aviv, you well might burn 4000 lbs if you got caught in a line up. However, with any luck you'd get to the runway without delay, and you'd only burn 2000 (maybe even a little less), and you'd have the extra fuel for later. You wouldn't have the whole 2000 extra, because it would take about 20% of that to carry it.

Why was the extra fuel desirable? Well, in general as they say, the only time you have too much fuel is when you're on fire. Seriously, though, an extra 1500 to 2000 pounds could make the different between having to divert to Athens for fuel or going on to Tel Aviv.

  So I was wondering, is there any margin for takeoffs with weights marginally higher than MTOW?

There is a practical margin but it's a judgement call as to how much it really is. If on the 747 all four engines stay running, the airplane will march right out, albeit with reduced performance, even if seriously overweight, but you've compromised the airplane's ability to stay in the air if an engine fails, especially if the failure is catastrophic.

Sometimes you're overloaded but don't know it. Either accidentally or on purpose the cargo weight you're carrying is misreported. The worst case that I experienced was taking a full cruise line crew and equipment from Miami to Trieste, where they would board a brand new cruise liner and put it in service.

We were at max gross and had enough fuel for that weight to reach Trieste. Once airborne at at cruise, we realized we were burning more fuel that we should. Using our mach number, altitude, and fuel flow we worked backward to find our weight and discovered we were somewhere between 30 and 35 thousand lbs heavier than we should have been. Our dispatch confirmed our calculations when we contacted them, and we made a fuel stop in Paris.

If you're flying freight, and pallets of uncovered dry goods are left out in the rain, they weight a lot more than when they were dry. That happened at Madras, India (now called Chennai) and that put us well over gross.

In a perfect world, neither experience should have happened. Welcome to the real world, at least as it existed in the 1990s.,


What aircraft would have these tail numbers?

I'm convinced this numbers were fligtradar-internal identifiers, nothing concerning the flights themselves. The following is not an answer, just what I know about flightradar data records and where to find data like yours.

The flightradar website on a computer updates its data by requesting this url, which contains coordinate bounds, filter settings and so on:

https://data-live.flightradar24.com/zones/fcgi/feed.js?bounds=40.19,39.78,-76.26,-74.03&faa=1&mlat=1&flarm=1&adsb=1&gnd=1&air=1&vehicles=1&estimated=1&maxage=7200&gliders=1&stats=1

I guess the mobile app is not different in this point.
The answer from the server is a JSON object like this:

{"full_count":14127,"version":4,
"b2fd160":["AD3C6B",39.9674,-75.9941,230,34000,368,"1306","T-MLAT2","MD88","N952DL",1475422448,"BDL","ATL","DL2457",0,0,"DAL2457",0],
"b2fe181":["A9FF54",39.9429,-75.9208,273,16860,378,"2347","T-MLAT2","B737","N743SW",1475422445,"PHL","PHX","WN601",0,1600,"SWA601",0],
"b2fc0bf":["",40.0910,-75.8714,230,39999,368,"1361","T-MLAT2","GLID","",1475422448,"","","",0,0,"GLID",0],
"b2fb3da":["A1A8DA",40.0949,-75.8623,98,8700,304,"3553","F-KPNE1","A320","N206FR",1475422446,"MKE","PHL","F91052",0,-896,"FFT1052",0]
...,
"stats":{"total":{"ads-":8655,"mlat":2916,"faa":1647,"flarm":346,"estimated":456},"visible":{"ads-b":6,"mlat":11,"faa":3,"flarm":0,"estimated":0}}
}

There is one line per aircraft, starting with a 7-digit, lowercase hex number, followed by any information about the flight in square brackets. (You can easily identify position, course, speed, registration, aircraft type and so on.)
From the structure of the file and from the fact that you can observe many subsequent hex numbers when you collect lots of data, it seems the first number is a flightradar-internal identifier, acting as counter. Whenever a new flight is detected, it gets the next number.

Within the square brackets, the first number seems to be the unique 6-digit hexadecimal (=24-bit) aircraft ID @JScarry mentioned (and the third entry, a glider, doesn't have one). But more interesting is that all data here is uppercase. (And according to this site, text messages from the aircraft like flight ID doesn't have upper/lower case)

Now, you have two subsequent, lowercase 7-digit hex numbers. This really looks like the flightradar-internal ID. So, maybe flighradar had a glitch, or it had absolutely no further information about that flights, and displayed the internal ID instead. What doesn't fit is the range, right now the numbers are about 164.000 (decimal) ahead. (EDIT: It can fit, they record 140.000-175.000 flights per day)

One can also retrieve data about flights with a certain internal ID from flightradar, but with your numbers, I get an empty record.

Yet, I think it was an internal ID, and you won't get the answer outside of flightradar.


How is "information relating to the safety of flight" defined by the FAA?

The language is intentionally vague.
Much like Justice Stewart said about pornography, when it comes to "information relating to the safety of flight" you'll know it when you see it.

Birds flying around in the approach path? Yup.
Wind shear on short final? Yup.
(Even if it's forecast/reported telling them how much airspeed you gained or lost helps.)
"Drone" buzzing around in the traffic pattern? Yup.
Deer grazing in the middle of a grass runway? Yup.
Bird strike? Absolutely.
(There are regs/procedures specifically for this.)
The guy in row 3J is threatening the flight attendants? Yup.
The guy in row 3J spilled his soda on his lap? …Not so much.


What are these "F,S,O" characteristic speeds?

F speed is the minimum speed at which flaps should be retracted from CONF 3 or 2 to CONF 1+F.
S speed is the minimum slats retraction speed, i.e. the minimum speed at which a clean configuration should be selected.
GD speed is the engine-out operating speed in clean configuration. In other words, it corresponds to the speed that allows the highest climb gradient with one engine inoperative in clean configuration.

source:
https://www.icao.int/WACAF/Documents/Meetings/2015/ICAO-BEA/SafetyFirstissue20.pdf


Do large aircraft have carbon monoxide detectors?

Haven't seen any. Cabin heating is done quite differently on jet aircraft than on pistons. Bleed air is taken from the engine before the combustion chamber, so engine exhaust can't end up in the cabin, even if there was a greater fault in the A/C packs.


Where can I find pictures of "endplate"?

I seem to remember that wing end plates were sometimes used on Short Take Off and Landing(STOL) aircraft in the 1960's.

I found a few photos while doing an internet search but they seem to be much more prevalent on race car wings these days.

Here is an explanation of why end plates are used on race cars: Analysis: Rear Wing Endplates

  The endplate has two functions, the primary reason for their shape is
  to control the wingtip vortices at the trailing edge of the wing as
  this reduces drag and also lift. The second reason is that they
  control how the airflow makes its way over, under or around the
  aerofoil device that is creating the downforce on the car, resulting
  in better airflow management and maximising the performance of the
  component.


What is the formula for estimating the maximum stationary thrust of a rotor as function of its diameter?

The dimensional approach is simple... It can be safely assumed that the lift $L$ is a function of the input power $P$, the diameter $D$ of the rotor and the air density $\rho$.

Thus, $L = f(P,D,\rho)$

where $f$ is a function to be determined.

From dimensional analysis, the lift $L$ can be easily derived:

The variables are Lift $L$, dimensions $MLT^{–2}$; Power $P$, dimensions  $ML^2T^{–3}$; Rotor diameter $D$, dimensions $L$ and air density $\rho$, dimensions $ML^{–3}$

The variables form a non-dimensional product $k$

$k = L^a\cdot P^b\cdot D^c\cdot \rho^d$  where $a,b,c,d$ are numbers to be determined.

Let’s form now a parallel product $k^*$ with the dimensions:

$k^* = (MLT^{–2})^a  (ML^2T^{–3})^b  (L)^c (ML^{–3})^d$

Clearly, $k^* = M^0 L^0 T^0$... We now take the exponents for each dimension:

$a  + b + d = 0 \\
a + 2b + c – 3d = 0 \\
–2a – 3b = 0$

We make $a = 1$, since $L$ is the variable we’re going to solve for.

$b = –2/3 \\
d = –1/3 \\
c = –2/3$

Then,

$k = L^a\cdot P^b\cdot D^c\cdot \rho^d \rightarrow  k = L\cdot P^{–2/3}\cdot D^{–2/3}\cdot \rho^{–1/3}$

Solving for $L$

$L = k\cdot P^{2/3}\cdot D^{2/3}\cdot \rho^{1/3}$

where $k$ is a constant to be determined...


What are the elements of an approach briefing?

Yes, it's true.  Usually called approach or arrival briefing

Details will vary according to aircraft and operator but a typical list is NATS:

  NOTAMs1

  ATIS2 notes, chart briefing point by point, date, frequencies, courses, minimums and missed approach procedures.

  Terrain, minimum safety altitude, which route

  Special notes for arrival, taxiing, likely gate for arrival?

I noticed that you specifically asked about something going wrong.  The following assumes a serviceable aircraft.

According to operator, if the aircraft is not on a stabilised approach by 1,000 feet, a go around will be performed and the missed approach procedure (MAP) followed.  The MAP is printed on the approach chart.  The initial action is:

to get the aircraft safely climbing away (aviate)
to the altitude and heading defined in the MAP (navigate)
then call ATC to let them know (communicate).

Aviate, navigate, communicate, always in that order.

A stabilised approach might differ between operators but is essentially.

  The flight path is correct with only minor changes in pitch and
  heading needed to stay on it.

  No more than 20 kts above the approach reference speed briefed as above.

  Correctly configured for landing (flaps, slats, gear, spoilers armed, autobrake set etc)

  Checklists completed

  Rate of descent <= 1,000 fpm

  Power setting is appropriate

  There may be other special checks for some types of approaches which must have been briefed as above).

The MAP might be something like:

Maintain runway heading and climb to 1500' until reaching 4 DME.  Turn right heading 250 degrees and climb to 5000' to join the hold at DISNEY

The MAP is unique for each approach so must be briefed in advance.

1
Notice to Airmen: Warn of recent changes, temporary restrictions, equipment malfunctions etc.

2
Automated Terminal Information Service: A continuous broadcast of airfield information such as weather, special precautions, runways in use etc.


How to calculate the best glide speed if there is none on the POH?

According to the FAA, the short answer to your question is approximately "halfway between Vx and Vy."
While there is a lot of physics and calculus that can give a precise answer to this question, there is another answer that uses "pilot math". The FAA has a nice publication titled Best Glide Speed and Distance, which explains that there are two different types of "best" glide speeds.

The glide speed that gives you maximum distance covered for a given altitude (Best Glide Distance); and

The glide speed that gives you the maximum time in the air (Best Glide Time).

Per the FAA document, the glide speed that gives you the most distance covered is approximately halfway between Vx and Vy. For example, on a C172 with Vx at 53 and Vy at 73 Max Glide would be about 65. The speed provided in POHs is usually calculated at Max Gross Weight, so your actual Best Glide Distance speed will be a little lower if your weight is less than max gross.
Alternatively, if your goal is to stay in the air as long as possible, then you'll want a speed that minimizes the descent rate. This is typically slower than Best Glide Distance speed, and can be easily determined by pitching for an airspeed that gives you the lowest vertical descent speed on the VSI. There are times when you don't care how far you glide, and instead want to maximize the time in the air in order to troubleshoot. For example, if you are over an area with no suitable landing location (like over the ocean), you'll want to maximize your time to try to restart your engine. Or if you are over your landing location, but want extra time to finish your emergency checklists.


Regulations regarding cleaning of water cooking equipment on planes?

From observing catering operations as a passenger on many flights:

Hot water is served from the same pots as coffee, so that only one type of hot liquid container is needed per flight. The pots are clearly intended for hot water or coffee. This doesn't mean that the flight attendants haven't used it for something else. For example, the galley sink might get clogged and the flight attendant uses the pots as a scoop to move the liquid to the toilet. I've seen this at least once.
Yes, everything with food contact has to be washed and disinfected, especially on international flights for phytosanitary reasons. They even will wash the trolleys. They cannot disinfect the pots on the aircraft, so at the end of the flight, they are placed back in the metal catering containers, and will be washed in the catering facility with all other supplies ("rotables").
There's no regulation or non-religious reason why you'd want to separate the coffee pots from the rest of the equipment, so I doubt any airline does this. Here's a page showing pitchers being washed with serving trays and drawers.

In the majority of galleys, the hot water comes from the coffee maker or dedicated water boiler, which operates like a commercial coffee maker: there's a constantly heated internal hot water tank that is automatically refilled from the aircraft water tanks. My understanding is that it may be best to have hot water dispensed directly from the maker, since that is dedicated for water use.


What is the name of centre of mass speed of an aircraft?

It describes what the velocity vector of the aircraft centre of gravity is in relation to the surface of the earth. Ground speed is the 2-D projection of your speed on the ground, climb speed is the vertical component.

Both ground speed and climb speed are very useful parameters as such: ground speed to figure out when the aircraft arrives, climb speed to adjust engine settings etc for reaching cruise altitude with a minimum amount of fuel used. The 3-D vector sum of the two has little practical use, that is probably why it has no separate name as far as I know.

The integrated signal is of more use: what is the position in 3D of the centre of gravity of the aircraft relative to earth? Pretty useful for navigation.