When are pilots required to have approval to conduct practice approaches?

Usually airports with approach controls will have it printed on the approach plate. Take for example the non-towered field Menominee-Marinette Twin County:

The approach control frequency is highlighted in the chart. This is who you receive approach clearance from. KMNM is outside of KGRB (Green Bay) airspace by a good 40 miles, but KGRB approach control is responsible for the airport.

So the short answer is: Look at the approach plate for the responsible frequency/agency for the airport.

I think the other part of your question is more along the lines of "If I'm shooting an IFR approach, am I required to get clearance via ATC?" This I'm not 100% sure about but I would guess that the answer is "yes" since you don't want to interfere with traffic shooting real approaches.

The Aeronautical Information Manual has advice for conducting practice approaches in section 4-3-21 (Page 204):

  (a) ...Practice
  instrument approaches are considered to be instrument approaches made by either a VFR aircraft not on an IFR flight plan or an aircraft on an IFR flight plan.
  To achieve this and thereby enhance air safety, it is Air Traffic’s policy to provide for separation of such operations at locations where approach control
  facilities are located and, as resources permit, at certain other locations served by ARTCCs or parent approach control facilities.

(Emphasis mine)

Furthermore, it goes on to say...

  (b) Before practicing an instrument approach, pilots should inform the approach control facility or the tower of the type of practice approach they desire to make and how they intend to terminate it, ...
  (c) At airports without a tower, pilots wishing to make practice instrument approaches should notify the facility having control jurisdiction of the desired
  approach as indicated on the approach chart.
  (e) VFR aircraft practicing instrument approaches are not automatically authorized to execute the missed approach procedure.

But as I say in my comment, the AIM is a guideline, not a rule and I don't think there is anybody stopping somebody from doing an instrument approach without controller notification, however because ATC isn't providing traffic separation at that point, it could be considered negligent of the pilot to not request ATC clearance. Besides, a good portion of conducting practice approaches is talking to ATC.


Can I choose whether hobbyist or Part 107 rules are more advantageous when flying a UAV for fun?

According to the FAA's own FAQ, you can do either (emphasis mine):

  There are two ways for recreational or hobby UAS fliers to operate in
  the National Airspace System in accordance with the law and/or FAA
  regulations. Each of the two options has specific requirements that
  the UAS operator must follow. The decision as to which option to
  follow is up to the individual operator.

  Option #1. Fly in accordance with the Special Rule for Model Aircraft
  (Public Law 112-95 Section 336). Under this rule, operators must:

  [...]

  Option #2. Fly in accordance with the FAA's Small UAS Rule (Part 107).
  This requires operators to:

  [...]

So, it's your decision. But as always, ask yourself first how you would justify that decision to the FAA if something goes wrong. As a certificated pilot, you actually have something to lose if the FAA decides to take action against you.


Are monoplane struts under tension, doubling the stress limit of the spar?

The spar on a strut braced wing effectively moves the bending stress out from the wing root to the strut attachment.  In other words, a strut braced wing is a cantilever wing from the strut attachment out, and will have the normal bottom cap in tension and upper cap in compression at that point.

Between the strut and fuselage, it's more complicated.  The spar along that section is like an inverted hammock being effectively supported at both ends.  It wants to bow up. At the root fitting, there are shear forces which depend on how far out the strut attachment is.  The forces are inboard and up if the strut attachment is closer to the tip, and inboard and down if the strut attachment is closer to the root (a Twin Otter's wing's root fittings are under inboard and downward shear because most of the wing is outboard of the strut attachment).  There is a 'sweet spot' point where you can attach the strut to the wing spar and the loads on the root fitting are straight-in compression with no vertical shear.

This is why you will see astonishingly small bolts attaching the wing root to the fuselage on some airplanes (as in, half inch, or 5/8 inch diameter bolts at the strut attachments, and quarter inch bolts at the wing roots); if the strut picks up the wing at the right location, the loads at the root are almost all very moderate inboard shear loads.

As far as spar bending goes, the most highly stressed location is the cap strip above and below the outer strut attachment and that is where the spar has to be strongest in bending, with tension loads on the bottom and compression loads on top, in normal upright flight.


When should the term "pan-pan" be used instead of "Mayday"?

Oddly enough, the FARs and the AIM do not define these terms even though they use them frequently, but it is in the Pilot Controller Glossary (see below).  This is one of those areas that I've never really been given specific training on and I guess figured that I would "know it when I saw it".  The definitions kind of support that since they leave it to the discretion of the pilot:

  EMERGENCY- A distress or an urgency condition.

  DISTRESS (MAYDAY)- A condition of being threatened by serious and/or imminent
  danger and of requiring immediate assistance.

  URGENCY (PAN-PAN)- A condition of being concerned about safety and of requiring
  timely but not immediate assistance; a potential distress condition.

Flight Safety released a report titled Use of Standard Phraseology by Flight Crews and Air Traffic Controllers Clarifies Aircraft Emergencies which includes a quote from an official in which she says that there is a misconception among some pilots about the difference between declaring mayday and pan-pan:

  I have observed many cases where a mayday is given when pan-pan should
  be sufficient.  Many pilots do not realize that this distinction is
  ATC's way of prioritizing two or more aircraft with an emergency at
  the same time.

She also included some of the most important factors to consider when deciding to declare an emergency:

  Is the aircraft in immediate danger?
  Does the aircraft require immediate assistance?
  Will the aircraft require priority handling during the approach or during any other phase of flight?
  Will the aircraft need special assistance on the ground?
  Does the crew need any assistance from other parties?

The most important thing though is not whether you declare exactly the right kind of emergency, but that you actually let them know when you need help.  Don't forget that you can also change your mind.  If you declared an Urgency condition and decide that you need more assistance/priority, you can always "upgrade" it to a Distress, and vice-versa.


Do pilots typically mix roll/yaw when piloting various planes?

Pilots typically make turns in the air by banking the aircraft. The act of banking the aircraft is done by moving ailerons. Since moving one aileron up and the other aileron down produces a roll in the direction of the up aileron, the aircraft will bank (and presumably turn) in the direction of the up aileron.
Induced drag is a byproduct of lift. By putting one aileron up and one aileron down, you are producing more lift on the down aileron side and less lift on the up aileron side. Therefore you are also producing a lot more drag on the down aileron side than you are on the up aileron side. This causes adverse yaw in the direction of the down aileron. So, while the bank is trying to fly the aircraft in one direction, the induced drag is trying to yaw the aircraft in the opposite direction. This is one type of adverse yaw.
While turning is done by banking through rolling instead of simply yawing, yawing must still be done. The main job of the rudder is to combat adverse yaw. Pilots are constantly making judicious use of the rudders to keep the flight of the aircraft coordinated and streamlined. Changes in pitch, roll, and airspeed can all cause adverse yaw.
Some more modern planes will do this to some degree for the pilot through electronics. The mechanism for technology to accomplish this is called the yaw damper. This, however, does not completely eliminate the need for rudder inputs like your “mix” setting does.


What date and time definition is used for the second leg of a flight?

You are looking at two different planes.

This is the flight from London to Singapore, which departed on 17th of August, on flightaware.com:

The dates and times are local, meaning the flight departed 2019-08-17T21:11:00Z (UTC) and landed 2019-08-18T10:23:00Z.

Before this flight even took off, another 777 departed Singapore headed for Sydney:

The flight departed 2019-08-17T11:56:00Z and landed 2019-08-17T19:09:00Z.

The plane which landed in Singapore on the 18th of August also continued to Sydney later that day:


The FAA has categorized disturbances into four levels:

  Level 1: Disruptive behavior - suspicious or threatening
    Level 2: Physically abusive behavior
    Level 3: Life-threatening behavior
    Level 4: Attempted or actual breach of the flight deck

These are also ICAO standard classifications from the restricted Doc 9811, according to IATA. I'm not sure who came up with them first. That IATA document also provides sample things that might be considered to be each level.


Why isn't the An-72 / Boeing YC-14 configuration used for airliners?

The extra lift provided by the blown flaps and the better protection against FOD is simply not needed in regular airline service, and the higher engine location will make maintenance harder and more expensive. Airport runways are long enough for most purposes already, and only tactical transports could possibly benefit from the enhanced lift and better FOD protection.

At least the An-72 and -74 is operated by a number of civilian and military entities. Note that all of them serve small, local airfields. Note also that passenger service with the An-72 has been discontinued in Finland since this type was not cleared there for passenger services.


Can I listen to control tower frequencies on a ham radio legally

In North America, just buy an air-band radio and listen to Raleigh-Durham tower all you like, or if your ham unit receives the aviation VHF frequencies, do that.  Or find it on LiveATC.net  It's only illegal to broadcast without authorization, not listen in.


What does a numbered dot mean on a sectional chart?

It’s a local elevation at a particular point, generally in a flat area as a reference base elevation for the area.


Is it possible to increase available take-off distance for a seaplane by turning?

Yes when I was bush flying in Northern Ontario (C-185 on straight floats) I used turning takeoff runs from time to time when loaded and with limited space.  You start the turn once on the step.  Step turns are a normal skill on floats although it's not a good idea to do it on choppy water in high winds.
The guy in the video had insufficient space to take off even with the turning takeoff run and it looks like he couldn't be bother to head farther down the lake to get a better into wind run.  I wouldn't have done a turning takeoff like that in that sort of windy chop.  I would've started right at the far shoreline as far as I could go, and determined a go-no-go point using a landmark that was about 2/3rds of the total run.  If you're not airborne fairly quickly (by water takeoff standards) in that kind of wind and waves, something is really wrong or your airplane is grossly underpowered.  I suspect that guy was overweight.


Can a landing aircraft snag multiple wires when landing on an aircraft carrier?

The answer is quite simple:

1. When touching down the nose is in a pulled up attitude, therefore the tail is farther down then normal. As soon as the airplane touches down (on all wheels), the tail is higher, thus the hook is higher.
You can see how the aircraft is in a nose up attitude, but gear and hook are on the same level. If the aircraft was sitting on all its tires, the hook would actually touch the ground. (This might not even be the case on all aircraft, though!)

2. This is the much more important reason: The hook is pneumatically pushed onto the deck (Google for the "F-14 Tomcat Pilot's Flight Operating Manual Vol. 1, Volume 1". Interestingly Wikipedia (is it a source?) says there are hydraulic and pneumatic hooks) but as soon as the hook hooks to the cable, and pulls on it, that pneumatic pressure is overcome and the vectors of the forces go from where the hook is attached to the plane to where the wire comes out of the ground (and vice versa).

Note: I guess its a combination of both, hydraulic and pneumatic. As hydraulics are not compressible, a valve would be needed to release the pressure built by the yank of the cable. So air pressure (pneumatics) would probably do a better job on keeping the hook down as long as no cable is attached. The retraction of the hook is done hydraulically though, and the way it is written in the F-14 Tomcat Pilot's Flight Operating Manual Vol. 1, Volume 1 it seems like the pneumatic pressure is kept even with the hook retracted...

As you can see here, the hook is actually almost parallel to the deck.

3. Last but not least: There is no space for two wires on one hook. Let's say the airplane would catch the first rope, and for some reason (it should definitely not happen, but let's just pretend it does) the hook is still on the ground where it would hook up to the second wire when crossing it, then it will maybe drag it along for a short time, but it can't really hook on as the hook is made to fit exactly one wire. This can be seen on this picture:


Don't know about the interior shots but for the exterior:

  In-flight shots use a model, some ground shots use N6723, c/n 18989/492, a TWA 707-131B.

This is from the awesome website IMPDb Internet Movie Plane database


What is "detonation" in a piston engine?

Detonation, as the name suggests, is an explosion of the fuel-air mixture inside the cylinder. Under normal operation, the spark plugs each ignite a point in the fuel/air charge, which then propagate through the cylinder and provides a consistent, regulated burn in a process called deflagration. This extends the time that the burning fuel pushes on the cylinder, providing a gentle power stroke.

During detonation, the fuel/air charge (or pockets within the charge) explodes rather than burning smoothly. Because of this explosion, the charge exerts a much higher force on the piston and cylinder, leading to increased noise, vibration, and cylinder head temperatures. The violence of detonation also causes a reduction in power. Mild detonation may increase engine wear, though some engines can operate with mild detonation regularly. However, severe detonation can cause engine failure in minutes. Because of the noise that it makes, detonation is called "engine knock" or "pinging" in cars.

(Source: FAA PHAK, page 6-18)

Detonation can be caused by a number of factors, but generally they relate to a situation outside of the engine's design. Using the wrong fuel can cause detonation: the octane rating of a fuel is basically the amount of pressure it can take before it detonates. Similarly, high cylinder temperatures can cause detonation(1). This is why mixture is set very rich when at high power levels: the excess fuel cools the cylinders, preventing detonation. As noted above, full power with carburetor heat on can cause detonation, as the increased temperature mimics the effect of high cylinder temperatures. Full carburetor heat is required to provide at least a 90 degree F increase in intake air temperature.

Further reading:

Page 6-19 of the Pilot's Handbook of Aeronautical Knowledge.
An article at Savvy Analysis

1) Detonation is distinct from pre-ignition, where the fuel/air charge is ignited by something other than the spark plug. Notably, detonation and pre-ignition often cause each other, as a detonating engine will have a very high CHT (potentially enough to cause pre-ignition), and if the charge pre-ignites as the cylinder is still rising, the continued compression may cause the charge to detonate.


What is the range and accuracy of ATC radar systems?

This is a general answer, not specific applicable to the situation in the USA.

There are several types of radars in use to monitor airspace.

Basically you can distinguish two classes of radar:

Primary radar does not require the aircraft to carry a transponder, it is a form of non-cooperative surveillance.
Secondary radar on the other hand requires the aircraft to carry a transponder; the transponder replies to interrogations from the radar. This is called cooperative surveillance.

Radars operate basically by line-of-sight, however due to atmospheric effects the radio waves follow the curvature of the earth to some degree. Aircraft flying low are quickly below the horizon, but aircraft at FL450 can be detected on secondary radar at ranges up to 300NM if the radar is operated for such range. Typically the range is less.

In general, the further the range that a radar needs to look, the slower it rotates. An airport surface radar may rotate as fast as twice per second, long range en-route radars can go as slow as once per 12 seconds. For typical TMA / TRACON use, 5 seconds would be in the right ballpark, for en-route 8 seconds will be about right.

The accuracy depends on the type of antenna, whether it is primary or secondary radar, and the distance of the aircraft from the radar head. The accuracy of the distance measurement are not so much affected by the range, and varies from about 5 meters to 300 meters. However, atmospheric circumstances can degrade these figures, especially at long range. The across beam accuracy is very much dependent on the distance from the antenna due to limited angular accuracy of the radar. The further you get, the worse the across beam accuracy becomes.


Can a steady flow have stagnation points?

The idea of a stagnation point is an idealization. This point is infinitesimally small, and air particles flowing along a streamline which leads into it will slow down on their way. The closer they come to the stagnation point, the slower they flow, and in the end they never arrive at the stagnation point.

In reality, air molecules have a finite size, so they flow either above or below the stagnation point streamline. Even if one particle manages to arrive at the stagnation point and stays in place (which is not possible in theory), a small angle of attack change will wash it away in the next moment.

One streamline goes away from the rear stagnation point which is located in the trailing edge. This point is doubly idealized, because it requires inviscid flow to have a rear stagnation point. Again, molecules flowing along the wall of the airfoil will be slowed down by the stagnation point pressure the closer they are to the trailing edge. Since they arrive either above or below the rear stagnation point, they will accelerate once they have passed the point of highest pressure and move on above or below the streamline emanating from the rear stagnation point.

The concept of a stagnation point is really helpful for understanding flow phenomena, however. There is really a line (in 3D it is a plane) which separates air that will flow over the wing from that which will flow below it. This line changes with angle of attack, and the simple stall warning vane is based on this principle. Once the line ends below the vane, air will press it upwards, closing an electrical contact which activates a buzzer in the cockpit.

Stall warning vane (small metal thingy sticking out from the wing)


Why does afterburner exhaust have "pulses"?

Those are known as "Mach diamonds" or "Shock diamonds" (and a number of other names) and are not a characteristic of the afterburner per se but are formed by standing waves in the exhaust when the pressure of the expanded exhaust gases do not exactly match external ambient pressure. They can be formed by either over-expansion or under-expansion of the exhaust gases. The diamonds form at the transition from sonic to supersonic flow which occurs immediately on the "downstream" side of a rocket or jet engine nozzle.
Photo from the link below:
SR-71 Blackbird taking off.

In rockets, flow through such a nozzle is always sonic at the throat (in all except trivially low pressure systems where it can be subsonic - but these are not usually encountered in practice.
In jet engines, whether flow is sonic or supersonic at the exhaust depends on the design which in turn tends to depend on the application. "Pure jet" engines which use a combustion driven compressor to compress input air and which develop their thrust from the jet exhaust will usually have supersonic exhausts. Ongoing development has led to a range of "jet" engine types with somewhat differing capabilities - turbojet ("pure" jet), turbofan (jet driven internal "fan" produces air which partially bypasses jet proper), turboprop (jet drives external propeller),propfan (turboprop on steroids optimised for close to Mach 1 cruise) and some fellow travelers such as turboshaft - like a turboprop but with shaft output - useful if you want to power eg a helicopter.
In a turbo-fan engine the amount of air which bypasses the jet engine proper is governed by the "bypass ratio". High bypass engines send most air past the jet proper to be combined with the jet exhaust and form the actual engine exhaust. Pure jet or some "low bypass ratio" turbo fan engines may have supersonic exhausts while "high bypass ratio" turbofan are always subsonic. Modern long distance aircraft (especially airliners) which aim for maximum fuel economy tend to have high bypass ratios. As Mach diamonds are only associated with trans-sonic operation you will not see Mach diamonds from eg a 747.
So, low bypass fanjets may have supersonic exhausts for part of their operation. A turbojet may be sub or super sonic and afterburner will almost always (but not necessarily in theory) produce supersonic outlet flow.
In systems which do have supersonic exit exhaust velocities, as the flow changes from sonic at the nozzle throat to supersonic in the expansion system the aim is to make the exit pressure exactly match ambient. "Exactly" never exactly happens in practice. Where the mismatch occurs there will be a shockwave - an "impedance mismatch in another perspective - and the visible evidence of this are the Mach Diamonds.
As both exhaust pressure and ambient pressure change with conditions there will essentially always be some degree of such shock waves present in "qualifying" systems, but more so when the engine operation departs more significantly from the ideal. Smaller versions may not be obvious without careful examination. As the overall system is usually optimised for "normal" conditions, afterburner operation is more likely to cause a major pressure mismatch as it deviates from normal use.
An exception would occur if the designers decided they wanted absolutely maximum performance from afterburner under given conditions (so that eg an interceptor could achieve absolute maximum velocity when needed) - in which case the Mach diamonds could be minimised on afterburner and would be more pronounced in normal operation.

See this page for some good photos and the diagrams below -

Aviation Aerospace - Shock Diamonds and Mach Disks

Below: creation of Mach Diamonds from under-expanded flow.

Below: - creation of Mach Diamonds from over-expanded flow.

Good explanation with pictures here - Wikipedia - Shock Diamond
Numerous relevant images - each linked to a related web page.

Related:
Wikipedia - Jet Engine excellent.
He178 0- the very first Jet aircraft
NASA visual Turbojet simulation


What is the relation between flap setting and aileron droop on the A350?

Some of the gliders I fly do the same: They do not droop ailerons in full landing configuration but do in intermediate settings. There the reason is aileron effectiveness at high angle of attack and prevention of a tip stall.

If you droop the ailerons it yields more lift but the angle of attack at which the airfoil stalls is decreased, which might give you a more violent stall. And if you suddenly deflect the aileron down further the flow could separate and cause "the wrong wing to go down". To avoid this airliners are often fitted with vortex generators on the outboard section (e.g. Boeing 737) but that was probably a no-go for the clean A350 wings.

Regarding droop vs. flap setting, the FCOM probably has the answer for that. Couldn't find it online yet. A380 does 5 degrees when flaps reach position 1+F or greater, A320 does 5 degrees when flaps reach 1+F or greater so it might be similar with the A350


Can motorjets be a viable means of propulsion?

Internal combustion engines (ICE) have great thermal efficiency, so driving a fan or compressor using an ICE is on paper very appealing indeed.

  It is well known that internal combustion engines are capable of achieving higher thermal efficiency than gas turbine engines.

NASA even looked at it in 1976. The proposal was to substitute a jet engine's combustor with an ICE. Two problems with that (according to Rolls-Royce) are the need for a gearbox and "component aerodynamic mismatching under certain engine operating conditions" due to the single-shaft design.

R-R filed a patent in 1995 that according to them fixes the problems with NASA's engine. So far we know why motorjets will have a hard time making a comeback.

R-R's solution is, more shafts, of course. They propose to have an ICE in place of the combustor, but this time it has its own shaft, fed by its spool's compressor, and the exhaust would drive a turbine (too many parts already) that drives a ducted fan (think turbofan but with ICE thermal efficiency).

  According to the present invention, an aircraft compound cycle propulsion engine comprises a propulsive fan and a core engine to power said fan core engine comprising an air compressor downstream of said fan, at least one rotary internal combustion engine configured to receive compressed air from said air compressor, a power turbine positioned to receive and to be powered by the exhaust efflux of said at least one rotary internal combustion engine, a first shaft drivingly interconnecting said power turbine and said propulsive fan, and a second shaft drivingly interconnecting said at least one rotary internal combustion engine and said air compressor.

Source: https://patents.google.com/patent/US5692372A/en


How to measure wind speed in a wind tunnel

A simple pitot tube attached to a fluid level balance can do this, if you can develop a pressure differential vs airspeed reference for it.


How do head- and tailwinds affect airspeed?

I'm wondering how to calculate the actual speed based on that.

Which actual speed? All of the speeds you mentioned are actual speeds. None of them is in any way artificial, virtual, or otherwise invented.

  Is it the groundspeed plus/minus the headwind/tailwind?

That would be airspeed, i.e. the speed at which the plane moves relative to the air around it.

  Meaning, if groundspeed is 500mph, and the headwind is 200mph, does that mean we're only traveling 300mph?

No. If groundspeed is 500mph into a 200mph headwind, this means that the plane has to fight against the headwind, i.e. its airspeed is 700mph.

Have you ever gone swimming where there is current? Can you imagine riding your bike on a treadmill?

  Meaning it will take us 10 hours to travel 3000 miles?

No. If the groundspeed is 500mph, it will take you 6 hours to travel 3000 miles over ground.


Is it worth it? Spending loads of money and years?

I'm not a pilot myself, but can provide some links here:

Burdens of working as an airline pilot
Do pilots make a lot of money?
Why is being a commercial pilot stressful?

You may also ask on PPRuNe discussion board, which is more suited for this kind of questions that are a lot based on individual opinions.

Here is an interesting article from Vanity Fair, that I often cite, about the increasing automation of aircraft, and the related impact on crew members: The Human Factor. The article starts with "Airline pilots were once the heroes of the skies. Today, in the quest for safety, airplanes are meant to largely fly themselves", which gives the tone.


For the panel image that you provided, I should be able to identify all major instruments:

A: Magnetic Compass - Pretty self explanatory. Note that in the real aircraft, A and K may have been switched.

B: Vertical Speed Indicator (VSI) - Indicates vertical speed, either up or down, in feet per minute.

C: Engine Tachometer - Indicates engine revolutions per minute (RPM)

D: Sensitive Altimeter - Indicates feet above Mean Sea Level (MSL). Adjustable for atmospheric pressure via Kollsman knob.

E: Air Speed Indicator - Measures indicated air speed, most likely given in MPH for this vintage aircraft.

F: Artificial Horizon - Gyro instrument giving an indication of an artificial horizon; shows pitch and bank variations.

G: Amp and Volt Meter - Amps are indicated on the left, volts on the right.

H: Oil Pressure and Temperature Gauge - Oil pressure is indicated on the left, in PSI, and Temperature is indicated on the right, in °C.

I: Clock - Probably an "8-Day", spring driven, hand wound device.

J: Magneto Switch - Control for ignition systems. This control only shows three detents. There should probably be four detents: Off, L, R, and Both (L and R refer to Left and Right magnetos).

K: Directional Gyro with Inclinometer - The bottom part is the Inclinometer (ball), indicates coordination and skid or slip. The top part is the Directional Gyro. Note that in the real aircraft, K and A may have been switched.

The inscription reading "NR2100" is indeed the aircraft registration, typically used as part of the aircraft callsign.

The knob below A is likely used to set the gyro compass (K) that should be in that location.

The knob below F is likely to adjust the pitch indication on the artificial horizon (F).

The red knob between F and E is probably meant to be a knob to cage the artificial horizon (F) and should actually be placed in the location of the screw directly above and left of that red knob. See the Bee Gee Z panel I linked to below.

The knob between E and D is probably meant to be a larger knob that might be part of a pull control. I have no real idea of what it is, but my guesses would start with carb heat, primer, starter engagement pull knob. Could be many other possible functions.

Reference the photos in this album by Roger Ritter depicting a Bee Gee Model Z. I understand that it is not the same model that you are looking for, but the cockpit layout is very similar, and should be informative. His photos helped me confirm the identification of the gauges in the panel image you provided. Photo album linked only, due to image copyrights.


What are the differences between the SR 71 variants?

Like every military aircraft built over the years, the aircraft evolve.  So to address the aircraft's history and all variants, let's refer to it as the Blackbird.

The Blackbird started out as the A-12 procured for the CIA. Fifteen of these were built with one being a 2-seat trainer. Two of the 15 were modified into M-21 aircraft prior to delivery.  The M-21 was designed to launch the D-21 drones. The SR-71 at the Intrepid museum (60-6925) in New York was built as an A-12.  One of the M-21's is at the Museum of Flight in Seattle with a D-21B drone.

Three high-speed interceptor prototypes were built and designated as the YF-12A and were capable of carrying 3 air-to-air missiles.  Two crashed and the third is at the National Museum of the AF.

The interceptor was cancelled and the RS-71 program, renamed SR-71 after LBJ's misstatement at the press conference, went forward for the AF.  Twenty-nine SR-71A's were built along with 2 SR-71B trainers.  When one of the trainers was lost in 1968, the surviving aft part of one of the crashed YF-12A's was mated to the front part the SR-71 static test aircraft to create the sole SR-71C.

There's a huge Blackbird community online.  Detail specs and history are available at blackbirds.net and at SR-71 Blackbirds.

The question of which is superior is an opinion, but one can assume that the SR-71's were "better" than the A-12's as they came later building on what was learned from both the A-12 and YF-12A.


How is the range/fuel computed when there is a 3-hour difference for the same route?

If there is a 100 km/h headwind, you can't hurry by that much. That will exceed the plane's capability. Likewise for a tailwind, that would be too slow for the plane to stay aloft.

So, the increase and decrease of speed in head- and tailwind does not nullify the wind. The 14-hour flight was the one in tailwind. Think of the wind as a fast wave, with the plane riding it, the faster the tailwind, the faster the plane gets there.

The keyword is air distance. Wind increases (headwind) or decreases (tailwind) the air distance flown. And therefore the 3-hour shorter flight, would have saved 3 hours worth of fuel, roughly.

From Wikipedia, the Dreamliner cruises at 903 km/h. Using the total time in the air, you can arrive at a rough estimate of how long the air distance was.

From the table here 'For a B787 in cruise, what is the altitude, speed, and angle of attack?', we are looking at roughly 15 tonnes of fuel saved on the 14-hour flight.

The distance between SIN and SFO is 7340 in nautical miles, always use the same units. The plane's range you found is for a typical payload, if there are fewer passengers, the plane flies for longer, as it is lighter in payload and can carry more fuel. And with the wind accounted for, the actual air distance is then known.

See these posts:

Is this ferry flight route possible for a B737-800 WL?
Why can't Norwegian's Boeing 787 operate from Vegas during hot weather?
When does the airline check if an airplane can reach its destination?


Can the MH-60 helicopter fly without one or all of the stabilators?

Assuming there is no STC ("Supplemental Type Certificate") that addresses this as an existing modification, the answer, in terms of acceptable aircraft airworthiness, is a hard no.

"Can the aircraft fly" is a tricky question in some ways, but dead-easy in others.  And remember: a helicopter is a thousand moving parts spinning wildly around an oil leak.

If you're looking at it from a flight physics and dynamics perspective, as a result of a mishap/damage in flight, (assuming no other problems like a damaged rotor or loss of hydraulic fluid,) and whether you can control the aircraft safely to the ground, a skilled pilot rated for this aircraft "type" would probably be able to wrestle the aircraft to a safe landing.  The main rotor does the work of holding the helo aloft, and the tail rotor holds the attitude steady against the torque of the main rotor.  The stabilator (stabilizer-elevator combined surface) does not contribute to total lift in hover, although it may affect lift in forward flight.

However, any mission the helo had been in the midst of should be immediately abandoned for the sake of making the landing.  Even if you were rescuing someone from drowning in the ocean, you're more likely to just add the flight crew to the tally of the dead if you persist in trying to make the bird work while in an adverse configuration.

This does not answer what an actual pilot of that type - which I am not - would experience in flight.  But the stabilator is considered a flight control surface, and you never take to the air without your flight controls 100% operational.

But ending up missing part of your flight control surfaces during flight would be considered an emergency condition.  If instead the aircraft is already on the ground, in need of maintenance, and one is considering a "ferry flight" to somewhere else to better service it, there are many things that an inspector could let slide for just a ferry flight, but this is not one of them.

Such a stabilator contributes to the control, stability, and balance of the aircraft, and without the entire stabilator, the aircraft is not in flight configuration, and therefore, it's not "airworthy".

Definition of Airworthiness:

  The aircraft conforms to its type design and is in a condition for safe operation.

Source: 14 CFR Part 3.5(a)

Even if a cogent argument is somehow made that the helicopter is "in a condition for safe operation" while lacking all or part of its stabilator, it still utterly fails the first half, being: "conforms to its type design".

A note regarding balance:
Many mid-sized helicopters have an acceptable CG (Center of Gravity) range that's about the size and shape of a large mobile phone (as I write this in early 2016).  This is a larger craft, flown by the military, so its CG envelope may be the size of a small to medium tablet device.  Loading various people near the CG location doesn't shift the CG very much, which is why the main passenger/cargo area is always under the main rotor.  But that stabilator flight control surface could weigh 20, 50, 100 pounds or more, and removing that from the end of a long lever arm at the end of the tail boom will cause a noticeable shift in CG location, possibly putting it out of range for the aircraft.  This is also a situation that a skilled pilot in an emergency may be able to compensate for if action is taken immediately, but is a condition you never enter into knowingly. That way lies only heartache and doom.

I am an FAA certified A&P (Airframe and Powerplant) mechanic, and during my training school, the third-ranking member in the entire FAA (in 2007) came and gave a talk on a few different topics, but primarily on the concept of airworthiness.  It comes down to this:  Are you SURE it will fly safely?  How sure?  Would you put your kids in that aircraft and let it fly?  As aircraft mechanics, we need to be that sure that the aircraft is safe to fly, or, it simply isn't.

  An aircraft is fully airworthy, or it's not airworthy.

The Sikorsky SH-60 Seahawk, without a complete stabilator, is not airworthy.


Has there ever been an uncommanded lowering of landing gear?

The answer to your question is, in fact, "yes" - but the circumstances involved demonstrate just how difficult it is to make an aircraft's landing gear deploy without being commanded to do so.

In 1985, CI006, a 747SP, experienced an uncommanded flameout of its #4 (right outboard) engine (something that particular engine was quite prone to doing) while cruising at FL410 en route from TPE to LAX.  An attempted relight failed, and a lack of corrective flight control inputs combined with a poorly-designed autopilot caused the airplane to decelerate and gradually roll into a steep bank despite the autopilot's attempts to counter the thrust asymmetry; the captain eventually noticed this and disconnected the autopilot, but made no flight control inputs of his own.

This, unsurprisingly, resulted in an immediate loss of control, and the aircraft rolled into a steep inverted dive, during which it exceeded mach 1 for an indeterminate period of time, plunging 30 kilofeet before the captain was able to orient himself when the aircraft broke out of the clouds at 11 kft and pull out of the dive, eventually levelling the aircraft at 9,600 feet.  During the dive and subsequent pullout, the aircraft was subjected to aerodynamic loads exceeding +5 Gs,1 which, in addition to causing severe structural damage to the aircraft (including tearing away large parts of the aircraft's horizontal tail), ripped off the body gear doors, broke the support brackets holding the body gear uplock hooks in place, and forced the aircraft's left and right body gear into the down-and-locked position.  (The added drag from the extended body gear [and from the aircraft's 29-kft maximum gear-down altitude] forced the flight to divert to SFO, having insufficient fuel to reach LAX with almost half of the aircraft's landing gear hanging out in the airstream.)

So, yes, it has happened... during an over-5-G pullout from a 30-kft supersonic dive in a 747.

1: The highest normal acceleration recorded on the aircraft's FDR was +5.1 Gs during the pullout from the dive; however, the absolute maximum G-forces encountered by the aircraft are unknown, as the extreme G-forces exerted on the aircraft, and the FDR, caused the latter to fail to record properly for large portions of the dive and pullout.


Why are aircraft not equipped with nose cargo doors when being converted from passenger to cargo variant?

The simple answer is there isn't the space. The problem with nose cargo doors is the cockpit. The cargo door must be high enough on the aircraft to line up with the main cargo hold to be useful. On larger aircraft designed with this in mind from the start, (747, C-5, An-124, An-225) the cockpit is placed in a location above the main deck so that the cockpit does not obstruct the path from the main cargo hold to the nose door.
This is specifically why the 747 was built as a two deck aircraft with the hump. They wanted to be able to fit a nose door, so they needed to put the cockpit on a raised deck, which left them with the hump deck for aerodynamic reasons.
However, on current generation narrow bodies, they simply aren't tall enough to do this. They are single deck aircraft, with the cockpit located directly in front of the main payload deck.


Are there procedures to follow in case of a suspect Electronic Control override (hacking)?

There are procedures for when some instrument indicates false values for how to find which one is not to be trusted and what to do if particular instrument cannot be trusted.

But for primary flight controls, not really. If the aircraft is flying on autopilot and initiates unexpected manoeuvre, the pilot will hit the autopilot disconnect button and take over manually. But beyond that, the pilot will just try more pressure on the controls to get the plane where he needs to. And won't really have much time to think about the reason.

You may want to look at the incidents and accidents caused by B737 rudder reversal. The rudder suddenly deflected in opposite direction than commanded and the pilots were not really able to understand what is happening in the short time they had to react. Somewhat similar incidents where the rudder failures of B747 (Northwest 85, here is captains account of the incident; there was one other similar occurrence). Again, the pilots just fought the controls; finding out what happened was not really possible and wouldn't help much anyway.

So I'd say there is really no time to "think it to be some sort of electronic control interference". The pilots would simply disconnect autopilot (if it didn't disconnect already due to pressure on controls) and then they would fight the controls.

Note that in all aircraft except Airbus A320 and newer and Boeing 777 and 787 the control column is mechanically (cables in smaller aircraft, hydraulically with some kind of power amplification on larger ones) connected to the control surfaces. So the pilots would be directly fighting the telekinetic power with their muscles. On Boeing 777 and 787 there is electronic intermediary, but the link is still bidirectional and control column position still corresponds to control surface position.

Only Airbus A320 and newer has the side-stick connected to a computer that calculates the final command from the pilot input and inertial reference. In this case the telekinet would either try to move the surfaces, but then would be fighting the computer, which has all power of the hydraulic system to it's disposal, or would try to move the side-stick under pilot's hand, but then the other pilot could press control priority button to take over. Of course even on Airbus the pilots can pull the circuit breaker and disable the computer, but then they are left with trim wheels and rudder pedals that both do have direct hydraulic links.


Autoland is an autopilot feature which allows the autopilot to control the aircraft all the way to touch-down and even a bit further.
Basic idea is that the autopilot is accurate enough to keep the aircraft on the correct approach path. This is achieved by (on top of really good software engineering) with at least 2 autopilot/flight director calculators. One of the calculators is the one in control, anfd the other one is monitoring the first one. In case of disagreement between the systems, a fault is announced and the approach must be aborted (fail-passive system).
There are also fail-active systems that require 3 autopilot channels. These are capable of continuing the approach even if one system gets faulted.
Some systems have a roll-out guidance to keep the aircraft aligned on the runway centerline after touch-down during braking.
Functionality is the same as with autopilot. The calculator gives commands to the control surfaces and thus steers the aircraft. In addition a radio altimeter gives accurate altitude information to enble flare and thrust reduction.


Currently, the 777 has engines that have a max thrust of 115,000 lbf, for a total of 230,000 lbf of thrust. The 747-8 has engines with a max thrust of 66,500 lbf, each, for a total of 266000. And just to throw in for comparison, the A380, currently has engines each producing 72,000 lbf of thrust, and a total of 288,000 lbf.

Right now the 777 has some of the highest thrust producing engines in commercial service. This does not take into account the extra thrust that is required for engine out issues. With a 2 engine design you have to have enough extra thrust for loss of engine during take-off at max take off weight. Whereas with a 4 engine design, you only have to have enough thrust to account for loss of 1 engine. So for a 747 twin engine aircraft, as a rough estimate you'd need to have each engine produce at least 150,000 lbf of thrust if not more.


On an ADS-B In display, do the pilots see the squawk code or call sign for other aircraft?

ADS-B is part of a system that compromises a number of different things. ADS-B (In) means that your aircraft is capable of receiving the ADS-B data, FIS-B and TIS-B as well. FIS-B broadcasts information such as weather. TIS-B is a traffic broadcast system.

ADS-B includes a number of messages (about 27 different messages), including:

Aircraft Identification
Surface Position
Airborne Position (Barometric)
Airborne Velocity
Airborne Position (GNSS)
Aircraft Status
Target State/Status
Aircraft Operation Status

Each message packet holds 56-bits of data. The aircraft identification message includes the aircraft type, category, and callsign.

Now, to a pilot, here is basically what you would see:

Source: NexAirAvionics.com

You can see that some targets include the flight number (JBU1075) and clicking on a target (this is in Garmin Pilot) will give a little more information on the target:

Source: Garmin.com

What the pilots don't see is the squawk code, this information is not useful to pilots because they don't really care about that for other aircraft. The only real use of ADS-B target information is to understand where other aircraft are. If a pilot needed to call up another pilot, they would do so by tail number or flight number. ATC Controllers and other pilots will never call a pilot by squawk code.

Why? Because the squawk code changes potentially many times during a flight. Let's take for example a simple flight from KGRB to KMNM (a flight I'm familiar with):

On the ground at KGRB, when telling ATC about my destination they will assign me a squawk code, for example 2044. After departing they will call me up "1205C turn on course, altitude your discretion" and I will acknowledge. About 30 miles out (if I didn't get flight following) they will say "1205C squawk VFR, frequency change approved". Now my squawk code changes to 1200. I might then pick up Minneapolis Center if I want to change my destination and they will assign me a different squawk code.

The one thing that remains constant there is my tail number. I know to listen for (and have mentally trained a "listen up" trigger when I hear) "1205-charlie" or "05-charlie" on the radio. ATC has been talking to specific aircraft using the tail number/flight number since the ATC system was born. Squawk codes match aircraft with targets on the radar (because before ADS-B all that was transmitted was the squawk code). This information is only useful to ATC and not other pilots.

Now if I'm cruising around and I see a target on my ADS-B that is headed in the same general direction I am, and I'm not talking to ATC, I can try calling that target using the tail number/flight number directly (this is done on the air-to-air band or a local frequency, don't broadcast on 121.5 or you'll hear "guaaaaarrrrrrd" from some obnoxious pilot).

Either way ADS-B is useful for traffic avoidance. I don't really need to know where that airplane is going, why it's going there, etc. I just need to know what it is (big jets can cause wake turbulence issues for smaller aircraft), which way it's heading, and how fast it's going there.


What is my BHP if I open full throttle and how is it controlled?

Rated BHP is measured at sea-level on a standard day. For the Cessna 152 I'm guessing you have an O235-L2 which is rated at 110HP @ 2550 RPM.

Now to understand how mixture affects the power produced by the engine you need to understand that the mixture knob controls how much fuel enters the cylinders to be burned with the air. As a combustion engine sparks, the fuel ignites but there is the fire triangle, Air, Fuel, Heat. Too much or too little of any of those pieces means a reduction of power or no power at all.

No, depending on the fuel type there is an optimum stoichiometric ratio where the proper amount of air and fuel are burned such that there is no extra air or fuel left over. For gasoline engines this is about 15:1, so for every 15 units of air, 1 unit of fuel is required. Having a richer fuel mixture results in an incomplete burn and may cool the cylinder temperatures, reducing power.

On the flip side, having too little fuel for the air can cause hotter cylinder temperatures and hot-spots on the cylinders. This causes detonation or knocking and can damage an engine very quickly. This is especially apparent in engines that have a lot of cylinder carbon deposits where the carbon can heat up and detonate the mixture before the spark plug does. Its like hitting the piston with a sledge hammer as its still coming up.

I don't have a graph from an O-235L but I did find one from an O-235C, which shows the relationship between throttle and BHP:

So you can see that reducing power from 2500 RPM to 2400 RPM gives a 10% decrease in BHP produced by the engine. Running at 2350 RPM is a 75% power setting (and in this graph nicely matches up with ~75 BHP). You can also see that there is a sweet-spot with relation to fuel consumption and produced power right around the 75% mark, which is usually refered to as the "performance cruise" value (best speed for fuel), and at 65% for "economy cruise" (best fuel).

So the mixture control needs to be leaned out based on the amount of air entering the engine. The levels of oxygen decrease with altitude and therefore the mixture needs to be leaned out. Its not uncommon for operations out of high altitude fields to perform take-offs with the mixture leaned, especially on hot days.

So its important to remember that the power produced by the engine is not a straight linear calculation. When you did your comment:

  But why the RPM is more and the BHP is only 75%? If I consider 2500RPM =110BHP then at 2400 it should be 105.6BHP which is 96% of total BHP

You assumed that the engine can produce power at 10RPM, which just isn't true. Lets take a better example and say that at 1600 RPM it is producing 25HP and at 2600 it produces 100HP, we can do the math then.

Using a linear interpolation formula this gives us 85HP which the graph tells us is 80 HP. Remember though, the graph is curved, and linear interpolation is, well, linear.


Components on engines, are they removed or blanked out?

Short answer

The reverser is not installed on the outer engines. As the linked question mentions: This allows to lighten the engines, this also prevents any unwanted and hazardous opening in flight as well as the costly check time for an unused feature.

The reverser used on the A380 is a cold flow type. It is merely part of the engine by itself. It is actually integrated in the nacelle structure channeling the bypass cold flow.

An engine should be usable in all four nacelles, the nacelles themselves cannot be swapped as they provide the reverser. The answer to this question seems to confirm this possibility.

Principle

Thrust reversal on this aircraft type consists in opening the bypass duct sideways, blocking the bypass flow in the duct and redirecting it through the opening. The opening is created by sliding the aft section of the nacelle case to expose a set of vanes. The blocked flow now escapes sideways and is guided forward by the vanes:

Principle of cold flow thrust reverser (source)

Thrust reverser on the A380 (source)

Engine, reverser, nacelle

The A380 is equipped with Trent 900 from Rolls-Royce or GP7200 from Engine Alliance. The thrust reversers are made by a different provider, Airbus-Aircelle (part of Safran), which also manufactures the nacelles. This is because the thrust reverser is really integrated in the nacelle rather than linked to the engine.

Trent 900

The reverser is in the cold / bypass flow behind the fan section which is the engine section with the largest diameter (in the Trent 900, about 3m!).

Hot flow, cold flow and reversed flow in a Trend XWB (similar to 900).
Based on RR picture

The cold flow duct (fan duct) is similar in both versions of the nacelles.  The duct is fenced by two semi-annular walls behind the fan frame, where the flow is rushed by the fan. This is called a double D-duct (in reference to the shape of the semi-duct).

The two D-ducts of an inner nacelle contain the reverser panes and their associated components. This version is named the thrust reverser unit (TRU). The other version without the reverser is the fixed fan duct (FFD), it doesn't slide.

TRU

The TRU is visible behind the fan section, source

On the image above, the two halves of the TRU are open. Note the outer wall of the duct has some thickness, contrary to the FFD wall (see next). This volume is used to host the mechanism needed to move the panels rerouting the flow.

The inner wall prevents all the flow to reach the core and the components and pipes around it, in order to not create damage or drag and heat. However a limited quantity of air is still directed toward the core for cooling.

More easy to see on this CG view:

Trent 900 duct and reverser. Based on TurboSquid models.
Top: 3D model by BlueGreen. Bottom: Another excellent 3D model by BlueGreen.

FFD

Left D-duct highlighted in blue.

Nacelle duct for cold flow. Based on image by Benny Zheng on Airliners.net


What are these lines on the fuselage of a 747?

No, they are just the boundaries between skin panels. See below for a picture of the 747-8 fuselage during assembly.

[

Boeing 747-8 front from side (picture source)

And this is how the panels for the cylindrical section look like before they are joined:

Boeing 747-8 fuselage panels. The original picture (source) is named "wing panel skins", but these are really fuselage parts.


How does an airline decide when to cancel a long haul flight permanently?

There are various reasons airlines may chose to stop flying a route. While its often financial there are usually underlying reasons that drive the decision. While financial models are drawn up when planning routes, outside factors may effect the finances in unpredictable ways.
Lack of travel: if a destination becomes unpopular or a city sees diminishing travel an airline may chose to stop flying the route, this may come after various scale backs.
Airframes get decommissioned: The economics of a route are often tied to the airframe used to fly it. Historically with the hub and spoke model smaller short range aircraft were used on quick routes. As airlines decommission old airframes some shorter (or even longer) routes are no longer financially viable.
Geopolitical reasons take hold: Its possible for government actions (generally related to visas and passports) to adversely affect travel and thus make a route either not profitable or completely not viable.
Changing Model: This ties into the airframe issues but over time airlines have changed how they approach travel, both as a company decision as well as a response to technological changes in the industry.
"Can't Land here": Sometimes you just can't get the plane in there
Airport Closures: Airports are by no means everlasting, they do sometimes close down
Bigger, Faster, Farther: There are lots of airports scattered all over the globe that acted as common re-fuel spots during the heyday of the large prop planes and were ultimately not needed during the jet age. While some of them remain as emergency landing spots they dont see nearly the traffic they once did and long distance routes simply bypass them.


Has it happened before the EASA and the FAA disagreed on the airworthiness of a plane?

It seems FAA and EASA did disagree since 2016 about 737max certification, and not just after the crashes. EASA certification was conditioned by training and more information to the pilots, which hasn’t been done.

Please refer to the following website:

https://www.cnbc.com/2019/03/29/reuters-america-insight-regulators-knew-before-crashes-that-737-max-trim-control-was-confusing-in-some-conditions--document.html

You read the following:

  The European Aviation and Space Agency (EASA) certified the plane as safe in part because it said additional procedures and training would “clearly explain” to pilots the “unusual” situations in which they would need to manipulate a rarely used manual wheel to control, or “trim,” the plane’s angle.

You may also read about EASA:

  The undated EASA certification document, available online, was issued in February 2016, an agency spokesman said:

  It specifically noted that at speeds greater than 230 knots (265mph, 425kph) with flaps retracted, pilots might have to use the wheel in the cockpit’s centre console rather than an electric thumb switch on the control yoke.

So when agencies give their approval it doesn’t mean the approval conditions are the same, it was not the case since the origine  for the 737max, and not just after the crashes.


Why would a flight take a detour on clean weather?

There are lots of reasons flights may not take a direct route, some are but not limited to:

It's just the route ATC assigned (for whatever reason they see fit)
There is an active military operations area or live firing area they are avoiding, these are not always "active" and may be avoided only sometimes.
Some kind of natural event on the ground, wildfire, volcanic eruption, etc.
There is a TFR they can't get through these are typically not hard bans on overflight but can be.
If it's an international flight they may not be allowed to overfly the airspace.
For smaller aircraft it may be a terrain avoidance issue (generally this is for general aviation sized planes).


Will this simple equation (pic attached) produce a rough estimate of the top speed of a prop driven aircraft?

The short answer is no, that will not give you a very accurate estimate. As other mentioned, your equation does not include lift. Given some basic engine specs and aerodynamic properties, the top speed for aircraft can be estimated by determining the intersection of required power and available power. Available power is based on selected engines and propellers, and required power is based on the wing loading, lift coefficient, and other parameters that describe the amount of power required to sustain minimum lift.


what type of sensors does the Boeing 737 MAX use for MCAS?

The pitot tube has nothing to do with the angle of attack. It is used for measuring pressure which in turn gives you the airspeed.

Accelerometers are used for the Inertial Navigation System.

The angle of attack is another sensor (shown below): the principle is that it rotates and reads the angle between the current position and the reference position.

Regarding the 737 MAX, there are two AoA sensors one on the captain side and one on the first officer side.

The MCAS reads the AoA from the captain side.


What angle are front rotors of tandem helicopters tilted and why this value?

The forward tilt of the main rotors with respect to the fuselage is not related to the tandem rotor design, but to a combination of fuselage lift and the need to also provide thrust with the main rotor.

First off, a review of other tandem designs shows that those not related to the CH-47 do not always share the forward tilt:

Bell XHSL-1 prototype

Filper Research Beta 200A

McCulloch YH-30

Piasecki H-21B

Yak-24

And looking at non-tandem helicopters, we also find a similar tilt:

Sikorsky CH-53

NHIndustries NH90

Mil V-12

Mil Mi-26

The reason is twofold:

A helicopter obtains its thrust from the same place as most of its lift: from the main rotor. This means that in forward flight the main rotor will always have its tip plane slightly tilted forward to counter the drag acting on the airframe.

Furthermore, large helicopters like the tandem designs you ask about experience significant aerodynamic forces on the fuselage at high speeds. To mitigate these, the main rotors are installed at an angle so that in cruising attitude the lift component from the fuselage will be positive. You can see it more clearly in flight:

NHIndustries NH90 in flight

Sikorsky CH-53 in flight

Boeing CH-47D in flight

I could find some corroboration of the fuselage lift effect in this Boeing report which includes a lift curve for the fuselage attained via wind tunnel tests. As you can see $\alpha_{zero-lift} \approx 4.5^o$

As to what is the exact angle, that depends on the design and is ultimately optimized after extensive testing, if deemed worthwhile.


Is a class B endorsement required for a Private checkride?

You do not need a Class B endorsement for your PPL Check ride.

By the time you get to you check ride you should have the first 8 endorsements from this list, provided by the FAA.

I will add one caveat to this. During your check ride your examiner will ask you plan a cross country flight. If the route calls for it and you have the endorsement you can plan it through Class B. However if you plan it through Class B your examiner may ask for the endorsement or try and trip you up over it. if you plan a course through Class B without the endorsement the DPE may not stop you when you get in the air. Be careful as you can bust a checkride for this.


Do you need a rotating beacon if you have strobes?

As required equipment for night flight, that’s technically feasible to do as this can serve as an anti collision light, provided the aircraft still has position lights and landing lights.  However, if you’re flying a certified aircraft, unless you have an STC to deactivate the beacon, you cannot as it’s listed in the minimum equipment list for the aircraft.  You’d be opening a can of worms to do so and there really seems to be no significant advantage in doing so.


How does the aspect ratio of the vertical stabilizer affect stall speed?

Generating lift creates downwash. Downwash reduces the effective angle of attack:

Source

A high aspect ratio reduces the downwash and thus also its reducing effect on the effective angle of attack.

Therefore a high aspect ratio wing will experience a higher $\alpha_{eff}$ than a low aspect ratio wing at the same angle, and thus stall earlier.

The same happens with the rudder, but then with $\beta$ instead of $\alpha$.

EDIT: clarifying alpha - beta similarity

So, in the case of sideslip, we have the following situation:

Source

See the similarity between the $\alpha$-image above, and the $\beta$-image.
The mass flow changes direction, and leaves the end of the rudder (more or less) parallel to the rudder chord line. This deviation in airflow direction causes the force to the left.

So for a normal wing ($\alpha$-image), flow enters straight, leaves going down (downwash) and as a consequence the wings give a force up.

For the rudder ($\beta$-image), the flow enters straight, leaves going to the right (downwash, but then sideways) and as a consequence the rudder give a force to the left.

About the stalling, stalling is not limited to the wings, also rudders can stall if the maximum effective angle they experience is above stalling angle ,and the force generated suddenly drops.

If we compare two rudders both with the same airfoil and the same $\beta_{eff_{stall}}$, say 10°.
The $\beta_{stall}$ will be given by:

$$ \beta_{stall} - \beta_{downwash} = 10° $$

If the $\beta_{downwash}$ is 4° for the low AR wing, and 2° for the high AR wing, it will mean the low AR wing will stall at a $\beta$ of 14° and the wing with the high AR will have a $\beta_{stall}$ of 12°.


How much thrust is produced on an A320 at takeoff and during cruise?

A320 family's engine of choice is the CFM56-5B. Now there are multiple variants of this engine. But on average the takeoff thrust for the models -5B1/B2 and -5B3 are between 30,000 to 33,000 lbf.
Other variants have a lower thrust rating between 21,000 - 24,000 lbf and 27,000 lbf.
The cruise thrust is lower of course since the aircraft has already taken off and now in upper atmosphere, with low drag and running at its best efficiency. Cruise thrust is about 4,700 to 5,800 lbf, although these are the maximum rated cruise thrust, so the engine thrust is always lower than that.
Say if the engine is rated for 5,800 lbs the actual thrust would be roughly about 5,300 - 5,500 lbs, maybe even lower.
Feel free to correct me if I'm wrong!
Reference
Cfm technical data


Would a canard work better for emergency pitch down?

A couple of confusion here. For starters, unless we are dealing with T-Tails, there is no deep stall for a tailed airplane. On the other hand, a canard airplane has the potential to enter deep stall.

Next, for a transport category aircraft, tail stalling in the positive incidence is generally not a concern. Tail stalling in the down load, however, is; for example, zero-G pushover in icing condition is a real issue to consider during design. In a well designed aircraft, the tail would have a higher sweep and lower aspect ratio than the wing so that the wing stalls earlier than the tail.

(Zero-G pushover may stall the tail because of the pitch rate build-up. Nose-down pitch rate equals negative flow incidence on the tail. Once the tail stalls, you lose the ability to pull.)

It could be an issue, however, if you have a T-Tail. For a swept wing in cruise configuration, the pitching moment would likely reverse near stall. At that point, the elevator would still have good effectiveness, but depending on how aggressive the pitch up is, there may not be enough time to lower the AOA before the aircraft enters deep stall.

Once in the deep stall, the authority on the tail as a whole decreases dramatically. Even with full nose-down stabilizer and nose-down elevator, you may not have enough authority to break the stall. In that situation, without an anti-stall chute, it's game over. The point is, you don't want to ever get there. Preventative measures include stick pusher and envelope protection functions.

Would installing a canard help? Sure, more authority always helps. But does it warrant the complexity and weight increase when other solutions exist? Probably not.


What would happen if an airliner had too much fuel for its next flight?

This would be an uncommon situation and the decision on what to do will typically be handled by your dispatcher.

Take the extra gas and restrict passenger/cargo weight as necessary.

This is the easy option but it could mean leaving people behind.
Defuel to the normal amount of fuel needed (e.g. release + taxi + contingency fuel)

This normally means the fuel is considered contaminated and will be disposed of.  There are ways of de-fuelling and re-using that fuel for another plane, but it requires specific operations and equipment that only likely to be available in the hub or perhaps a maintenance station.  De-fuelling can be slow and will delay the flight.

In the end this comes down to either weight restricting the plane or taking a delay and wasting some fuel.  The timing and economics of the decision will depend on many factors and each case would be judged individually.


What is this "Supersonic French" aircraft?

I believe this is the Alpha Jet

Source of pictures: Wikipedia
It is famously used by the Patrouille de France (the French military acrobatic demonstration unit). They are most famous for overflying the Champs-Élysées during the July 14 celebration, drawing a French flag in the sky.


What is the most effective of propeller's rotation in a two-propeller engine airplane?

TL;DR: The first one.

It all comes down to P-factor.

Airplanes fly at a positive angle of attack, so as you can see, this AoA for the wing translates to positive AoA for the descending blade. Vice versa, the positive AoA for the wing is negative AoA for the ascending blade. I.e., the descending blade has more thrust than the ascending blade under AoA.

Now it is pretty obvious why you want the descending blade on the inboard and ascending blade on the outboard, because in a single-engine-out incident this creates a less yawing moment to the otherwise arrangement.

However, life does not always turn out as we want it, as the engineers at Lockheed learned the hard way when testing their XP-38. They had gone through the trouble of using handed engines and props, making the starboard engine turn counterclockwise and the port engine clockwise. Now the fighter appears to be perfect: no torque, no gyro, a minimum yawing moment in a single-engine-out situation. But the XP-38 had pitch control issues which were later found out to be caused by the downwash created by descending inboard blades hitting the wing section between the boom and the central nacelle, creating a disturbed airflow trapped between the twin booms and finally affecting the elevator. In the end, they had to switch the engines' positions so the P-38 ended up with two critical engines.


Why is a model quadcopter 'better' than a helicopter? Why doesn't this scale up to the full-size versions?

Cheap MEMS gyroscopes have been on the market only since maybe 10 years. Before you needed more bulky and expensive gyros. Also, cheap and powerful micro controllers which can process the sensor data quickly enough and can control the speeds of the four motors to stabilize the quadcopter have only been available recently. The third recent innovation was more gradual, but also the storage density of batteries was not available maybe 20 years ago. With modern LiPo batteries you can have flying times of several minutes where NiCd batteries only gave you a fraction of that time for the same mass.

For your second question: The reason is similar to why birds have not been scaled up to carry humans, like horses do. This answer should give a good explanation.


What prevents DC-9 series aircraft from being reengined with more-efficient engines?

A re-engine program can be pretty expensive. This can make sense on military aircraft that take much longer to accumulate hours and cycles, or even cargo aircraft like the DC-8 in a similar position.

But the newest aircraft in the MD-80 series are going on 20 years at this point. They just don't have enough life left to justify that kind of expense. Most of them are not equipped with glass cockpits. When you add on the avionics upgrades needed, it becomes more cost effective to just buy a 737 or A320 which comes with the latest engines, avionics, and other features.

You're going to need a major manufacturer willing to take on the effort of an engine replacement program. That would point to Boeing or Airbus, and that would only cut into their existing narrow body sales.


Would removing heat from the compressor and adding heat to the turbine increase a gas turbine's efficiency?

Heat removal like that is sometimes done in gas turbine engines, not by cooling the compressor during operation, but by the use of an isobaric intercooler between the low and high pressure compressors.  These kinds of configurations are common in industrial gas turbines used for electric power generation, marine propulsion and other applications where extra weight is not as large of an issue as is with aviation gas turbines.

As far as adding this extracted heat energy back into the gas flow through the turbine section, this would not be possible as compressor outlet temps are in the neighborhood of 450°F where exhaust gases exit at around 1000°F, preventing a return of the compressor heat to the turbine section for extra power.  Typically intercooler exhaust is simply vented into the atmosphere.

More commonly, gas turbines are used in combined cycle powerplants which make use of the gas turbine exhaust heat to power a water boiler driving a steam turbine and secondary generator.  Some of the thermodynamic cycles used in these systems can be quite elaborate and can achieve an exergetic efficiency of over 60%, making them the most efficient heat engines on the planet.


What procedures will cockpit crew follow during a sudden depressurization?

In the EMB-145 I flew, the procedure for rapid depressurization was:

                   RAPID CABIN DEPRESSUIZATION

         Aural Warning                    Condition
         ━━━━━━━━━━━━━               ━━━━━━━━━━━━━━━━━━━━
         Voice Message            CABIN ALTITUDE INDICATION
            "CABIN"               HAS EXCEEDED 10,000 FT AND
                                        BECOMES RED
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Crew Oxygen Masks ........................................ DON ┃
┃ Crew Communication ................................. ESTABLISH ┃
┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛

  Passenger Oxygen ................................. AS REQUIRED
  Maximum Altitude .......................... MEA OR 10,000 FT.,
                                             WHICHEVER IS HIGHER
 ┏━━┓
 ┃IF┃  Emergency Descent Required:
 ┗━━┛  ATC .............................................. NOTIFY
       Emergency Descent Procedure ..................... PERFORM

                              * * *

The priority is getting your O2 mask on and then make sure the other pilot was able to get his on as well and help if needed.  The passenger O2 will automatically deploy if the cabin altitude gets high enough but you can force deployment from the cockpit.  If the depressurization is rapid and/or sudden an emergency descent will be performed to get down into breathable atmosphere ASAP (regulatory requirement time limit).  In the case of emergency descent our procedure did have a PA to make sure everyone was seated and seat belted for the maneuver.

The cabin crew will have their own procedures and while I'm not familiar with them they are equipped with portable oxygen cylinders and have the ability to move around the cabin and assist passengers with masks.


How does ATC radar display differ from military radar?

This link

has numerous depictions of Raytheon made STARS (Standard Terminal Automation Replacement System)

Wikipedia says

  The system is currently being used at a number of TRACON sites throughout the US2 and a number of military RAPCON sites that control military air traffic.[3]

  The STARS is part of the FAA's TAMR project to replace aging hardware and software at TRACONS. It is also called TAMR Phase I.[4] The larger TRACONs still use Common ARTs capable equipment but the FAA announced in Spring 2011 that TAMR Segment 3 Phase 1 will consist of replacing these 11 larger TRACONS with STARS by 2016. Simultaneously, all Terminal areas in the United States will phase out all CARTS and ARTS systems and switch to STARS. The smaller sites will transitions to the STARS ELITE (Enhanced Local Integrated Tower Equipment) version of software and hardware, which is similar to TAMR, but with minimum redundancy. The FAA plans to complete this process by 2020.

So it would seem that in many locations there would be no difference.

  Raytheon's DoD STARS, also known as DoD Advanced Automated Systems (DAAS), provides a state-of-the-art air traffic control system for managing terminal area airspace for the US military.

  DoD STARS includes 191 RAPCON facilities with 59 associated towers and 21 stand-alone towers.

  STARS receives radar data and flight plan information and presents the information to air traffic controllers on high resolution, 20" x 20" color displays allowing the controller to monitor, control, and accept hand-off of air traffic.

  The Terminal Controller Workstations (TCW) provide position-by-position in-place replacement of failing existing system displays. They provide up to 14 adaptable data block types and 16 adaptable list types to accommodate current and future display requirements. The TCW also provides controllers with preference sets that allow for ease in shift changes and re-sectorization.

  The color displays are specially developed for air traffic control and are capable of displaying six distinct levels of weather data (identified by different colors) simultaneously with air traffic, allowing controllers to direct aircraft around bad weather.

  The color displays are specially developed for air traffic control and are capable of displaying six distinct levels of weather data (identified by different colors) simultaneously with air traffic, allowing controllers to direct aircraft around bad weather.

  STARS is capable of tracking up to 1350 airborne aircraft simultaneously within a terminal area. The system interfaces with multiple radars (up to 16 short and long range), 128 controller positions, 20 remote towers, and a 400 by 400 mile area of coverage.

  STARS has two separate, fully redundant automation systems running in parallel providing an instantaneous back-up service to controllers. The Full Service Level (FSL) is based on Raytheon's AutoTrac air traffic management system and the Emergency Service Level (ESL) is based on Raytheon's TracView automation product.


In FAA-land the AIRAC cycle effective time is 0901Z. Your old charts were valid until 13 September 2018, 0900Z, the new ones are valid since 13 September 2018 0901Z.

I can't find the regulation that says it's always the case, but Google FAA 0901Z and you see that will give a ton of new charts / publications.

Here is a Jeppesen publication that explains the interpretation of the effective date.


What is the difference between Part 121, Part 135, and Part 91 operators?

So loose guidelines to match the loose question...

Pt 91 - generally private flying.  That is, no flying an airplane with paying customers unless those customers are government officials on government business.  This rare exception is called "public use"...it gets more complicated but let's leave it at this for now.

A rich guy who owns a jet to fly around in (or a company that owns a plane for business use) can be pt 91 as long as they don't sell seats or cargo space to the general public.

Pt 121 - scheduled commercial air service with paying customers.  Planes are flown on defined routes as often as the operator wants.  This is where companies like Delta and American operate.

Pt 135 - on-demand and scheduled charter.  When you call a company and say "take me (or my freight) fom LA to NY" you are likely talking about a pt 135 unscheduled charter. "Scheduled" charter is allowed but is limited to a few days a week (four, I think).


In instrument flight, when a Radial is given, it is always the “From” indicated radial on your OBS. In vectoring, turning an aircraft at acute angles is avoided. Flying a Heading of 120° to intercept a Radial of 150°, your only option would be to turn toward a course of 150° degrees (Southeast) until reaching 9000 feet MSL. The field elevation is already almost at 4000 feet MSL. You only have to climb another 5000 feet before you can turn on course. The dead giveaway is the fact that a course of 330° would have you passing in or over the KBIF military Class D. Probably, before you could affect a frequency change


Is there an official method to do pre-departure briefings?

The article linked below may be highly relevant, although it isn’t endorsed (directly) by any regulatory body. It describes how one company dissected their briefing concept and proposed improvements following a critical review of the adequacy, effectiveness and safety impact of their briefings in the operational context: Briefing Better


Is it common for a cold reciprocating engine to stop at idle?

What you experienced is common, but it would serve you well to better understand your engine.

There are quite a few engine options for the PA28, so without more specifics I cannot give you specific guidance, but I will address this in a general form.

Spark plugs foul from several different sources.  The leading sources are from excessive unburnt fuel, and from oil.  The unburnt fuel can cause carbon and fuel based buildup on the plugs, or it can come in the form of lead fouling, where lead deposits bridge the spark gap or insulator in the spark plug. Oil fouling tends to happen in higher time engines, but can happen in new engines during their break-in period.  Normally, running at cruise power keeps the plugs clean by scavenging these deposits off.

Again, engines vary, and manufacturer's recommendations vary, but in general, I run with the engine lean during taxi. This reduces buildups and will clear some fouling.  Because the engine running is impacted by engine temperature, I generally do not do a run-up until after taxi, when the engine is warmer.

If an engine is running rough, or the mag check fails, or the engine repeatedly stalls, I will do a clearing run-up, where the engine is run at a higher power setting, typically 1800 to 2000RPM and leaned until it will just continue running. This creates higher temperatures, and tends to burn off oil or other fouling.  This is done for anywhere from 1 minute to about 3 minutes, and then the mixture is enrichened and a normal run-up and mag check are done.

Magnetos do not foul, rather spark plugs foul, and typically the R mag will run the top plugs on one side of the engine, and the L mag will run the top plugs on the other side. Bottom plugs tend to fould more, especially if there is oil fouling. But the point is that whether the L or R mag fails, or runs rough, doesn't tell you exactly what spark plugs it is. A cylinder temp gauge or other instrumentation may, but usually it is determined by disassembling and inspecting the spark plugs.

So to get to the OP question: Large drops at runup are a sign of either a condition which may resolve itself, or conditions which are causing the engine to run less effectively. If they can't be respoved the plane needs to be seen by a mechanic, or someone more familiar with it.  If the mag is rough, and the engine has just been started, then it is premature to perform a normal mag check.  Let the engine ward up more, during taxi, and then check the mags.  The engine should not die at idle.  If that happens repeatedly after the engine is warmer (not even up to operating temps), then there is a problem, and the engine should be checked out by a mechanic or someone with more experience.

In addition to not clue as to what engine you are dealing with, we also don't know the local meteorological conditions. If you are having problems at 0F it is more typical than having problems at 35F.  But in general, engines should not stall at idle even when cold at 40F temperatures.

A final comment. I have trained many CFIs, and I spend quite a bit of time on engines and their operation and work-arounds.  Much of this is not in FAA publications, or even training publications. I find that many CFIs are not a knowledgeable about engine operations and related methods. Being engine smart will help you in your flying, and it will reduce your risk.

Addendum:

As a general rule:  Lycoming: R Mag top left plugs, cyl 2, 4 and bottom right plugs, cyl 1, 3.
Continentals: R Mag fires the top plugs, L Mag fires the bottom. The impulse is the R Mag, as the top plugs tend to get less oil fouling.


I've never seen "sliding" rudder pedals in a light GA plane - though there may be such designs in transport aircraft, especially fly-by-wire planes.

If you're looking for simplicity for a homebuilt aircraft or simulator I'd go with hinged pedals pivoting at the floor similar to what you'll find on a Piper Cub (which can be made by welding tubes together into an I shape), or any number of similar floor-mounted designs:

(As shown in the first picture, toe brakes can be easily retrofitted onto such a design, and as shown in the second you can mount square pedals on them if you want to, though the round bar has some advantages.)


To what extent is the clerical work (i.e. amending flight plans, logging, etc.) of a center air traffic controller now automated?

... Do center controllers have to manually amend every flight plan now that ERAM is fully implemented? To what extent is the process automated?

Yup. ERAM does not take away tasks from controllers, it just makes them easier.

  For controllers, ERAM provides a user-friendly interface with customizable displays. Trajectory modeling is more accurate, allowing maximum airspace use, better conflict detection and improved decision making. — FAA

Controllers still fill out and pass on flight strips. Physical flight strips are being phased out by the Advanced Electronic Flight Strips (AEFS), for center controllers and all the other facilities.

  AEFS replaces traditional paper flight strips, and manual tracking of incoming and outgoing flights, with an electronic flight data display. The system can be updated through a touch screen or mouse. Controllers no longer need to physically carry a flight strip across the control room. A simple swipe of the finger sends the data to another station. This allows the controller to stay engaged with the traffic at all times. — FAA

AEFS will eventually be replaced by the Terminal Flight Data Manager (TFDM).

It wouldn't surprise me if they print out those flight strips, just in case.

Source: FAA


Which airplanes require two (or more) pilot/operators?

The question boils down to,

  "Are there any critical flight controls that are out of reach of the
  Pilot In Command?"

Some older aircraft that required a Flight Engineer in the third seat (not the copilot) and controls at that station that were not available to the pilot or copilot. Some older variants of the 747 (pre 400 series, not sure if any are still in service in their original config) had a required 3 man crew. The Concorde (when it flew) had its fuel system controls at the FE station and those had to manned in flight as the fuel had to be moved around during different stages. You may be more likely to find these older airframes/configurations in cargo service these days. For these planes the legal requirement is often 3 people (not 2) but from a pure "get it off the ground, fly it, land it" case you need at least 2 people to operate it.

The FE station looks something like this in most planes (747 in this pic)

(source)

The Concorde had a pretty daunting panel as well

All that being said you would need at least a Pilot and FE to physically fly the plane since the pilot cant reach all the controls.

Modern avionics controls (glass cockpits mainly) have allowed more information to be presented directly to the pilot in a more condensed manner and allows displays to have multiple functions unlike gauges which tend to display only a single datum.


What are the drug testing procedures for EU airlines?

I am not a pilot but you may find the following useful:
Civil Aviation Authority, INFORMATION NOTICE, Number: IN–2015/012

5 Drug and Alcohol Screening Programme
5.1 The  testing  process.
Trained  staff  should  carry  out  screening  tests  usually  by  mouth  swab,  breath,  blood,  hair   or  urine  sample.  Tests  are  becoming  simpler  to  administer  and  less  invasive  as  the  technology  continues  to  improve.  Minimal  notice  should  be  given  of  the  intention  to  undertake  random  testing.  The  sample  collection  and  testing  process  should  be  designed  to  ensure  the  result  is  reliable.  If  a  positive  result  is  found  further  (usually  blood)  testing should be undertaken. A confirmed positive result should be reported to the relevant Civil Aviation Authority regulatory authority; in the UK the report should be sent to the Medical Department of  UK CAA  for aviation licence holders.

It is easy to find companies whose business is testing UK pilots for drugs, for example AlphaBioLabs:

Protecting the aviation industry with drug and alcohol testing
We specialise in providing drug and alcohol testing to the aviation industry for both individuals who want to show that they are drug or alcohol-free and companies as part of their drug and alcohol testing policy.
Our aviation industry workplace testing consists of the following:

Random drug and alcohol testing
Pre-employment drug and alcohol screening
For-cause drug and alcohol screening
Post-incident drug and alcohol testing
Abstinence monitoring

We have a team of fully trained sample collectors in your area, ready to collect your drug and/or alcohol samples from your place of work or any safe environment.

...

Hair drug testing
Hair drug testing is a form of workplace drug testing that can be used to support other methods such as oral fluid and urine testing.
It can be particularly useful for a more comprehensive overview of a person’s drug use as it is known as a ‘wide-window’ form of testing, which can determine a history of drug intake for up to 12 months.

A different lab reports

British Airways, for example, tests urine for drugs and breath for alcohol. Workers can be randomly tested in the first six months of employment or if returning to work after rehabilitation, and can also be tested if it is suspected that drugs or alcohol may have caused an accident, or if they are suspected of being under the influence while working.

Relevant incidents might include things like this:

Air Astana, which is part-owned by UK firm BAE Systems, said it fired the pilot immediately and had a zero tolerance policy for drugs and alcohol.
In a statement to Reuters it said: “The airline regularly tests its crews for alcohol and drugs using a random sampling method."


Is Fluid Structure Interaction considered in aircraft design?

Just one example: Good designers put the aileron pushrods away from the elastic axis of the wing to enable the deformation of the wing to create a damping deflection of the ailerons. This is especially helpful for high aspect ratio wings:

When the wing flexes, the pushrod will not be compressed, so will become relatively longer than the surrounding wing structure. This will create a negative aileron deflection which works against the lift force which flexes the wing in the first place. Doing this is particularly helpful in damping wing flutter.

Generally, the engineers make sure that every aircraft component works as intended even when the structure is deformed. Another example: To compensate for differences in the thermal expansion of different components, pushrods in glass fiber fuselages have two halves, connected by a pivoting lever, so that changes in their length will compensate.


Where can I find maintenance manuals for the A380?

You’re going to be looking for the Airbus Illustrated Parts Catalog (IPC) for the A380 airplane.  It’s something I’m sure you can request from Airbus, but it’s gonna cost you.


Which Airline don't use the Flight Number 191 anymore because of bad luck?

Well, you can be pretty sure that Delta and American no longer use that flight number, as it is pretty standard for airline to retire a flight number of an accident flight.

Beyond that, I'm sure there are a multitude of carriers still using Flight 191.

For example, Air India 191 is in-flight at the time of writing . Air Canada 191 is scheduled


How does the traffic pattern at a large airport affect nearby, smaller airports?

Generally speaking when airports like this are close together the airspace is designed to allow operations at both airports to occur without interfering with each other.

Broadly speaking if one airport changes approach direction it may be the result of a wind change. Assuming the local prevailing winds shifted its likely the other airport will change approach direction as well due to the wind shift.

The VFR sectional actually sheds some light on your specific area in question

(source)

In other words, if your flying VFR its likely that IFR aircraft from the outer airfields will initial be assigned to 3000 ft. (so keep your eyes on the lookout) and if we look at the Class B floors around that area 3000 keeps you under them in most places. In a round about way you can infer that controllers are going to assign and vector you under the class B to keep you out of the ATL area. Runway turnarounds or not.


Why are there some airports not charted as service-available when FBO provides fuel?

The chart supplement states that 1O5 is unattended, which fails the attendance requirement. And fuel is self-service for both 1O5 (FBO: Steelman Aviation) and SIY (FBO: Eagles Nest Aviation), which is also a reason for not having the tick marks.
Tick, tock
Your concern was discussed in the Charting Group Meeting 15-01 on April 28-30, 2015 (exactly two years ago):

Many pilots believe that the tick marks indicate the airport has fuel.
Over the past 20 years, many airports have gone to self-service fueling, eliminating the need for an "attendant" to be on duty to provide fuel services.
Several airports have contacted us, requesting the tick marks be placed on their airport symbol because they have fuel.
Recommendations:
Revise the charting criteria to:
Services available – To qualify as an airport with "services available", the minimum requirement that fuel is readily available (self-service or via attendant) 24 hrs/day.
Eliminate the requirement for attendant hours.

Outcome:

Rich Fecht, AJV-5223, reviewed the topic. Rich stated that the IACC Requirement Document has been signed and is ready to implement. Visual Charting is parsing through the data to get a list of airports that meet the fuel availability requirements and will soon start updating the VFR charts. Rich anticipates that the updated airport fueling information to be reflected on all charts within about two years. This change will affect public airports only.
Lynette Jamison, AJR-B11, stated that the proponent of this item should reach out to the state inspectors to let airports know how they can get fuel availability shown at their airport.

That means that both airports should get their tick marks soon enough if they want to.
2018 Update
With the release of new sectional charts on 29 Mar 2018, SIY got the tick marks:

(skyvector.com)

2021 Update
Both now have the tick marks:

Note: the chart supplement does not have to mention temporary shortages according to IACC 8 section 3.1.5.5.4.5:

The following type data shall NOT be published in the SERVICES and REMARKS sections:

g. Temporary shortages of certain types of fuel, starting equipment, or other aircraft services;


How can a military combat pilot indicate surrender?

There is no universally accepted means of surrendering an aircraft. According to Humanitarian Policy and Conflict Research at Harvard University,

  Aircrews of a military aircraft wishing to surrender ought to do everything feasible to express clearly their intention to do so. In particular, they ought to communicate their intention on a common radio channel such as a distress frequency.

They can do other things like rocking the wings, jettisoning the weapons, flashing navigational lights etc. However, none of these are universally accepted or even have a clear meaning in the heat of combat. So the best course of action will be to bail out.

If a pilot is captured by an enemy, there would be no need to surrender.


When do you contact ATC when departing from a non-towered airport into class B controlled airspace?

I'm assuming you're VFR.

You contact ATC before you enter the Class B air space.

If necessary, you orbit outside, but you don't enter until after you hear the magic phrase "<your callsign>, cleared into the Class Bravo airspace" from ATC.

If it's a busy time and/or the weather is poor, you may NOT get that clearance.

See this blog for a more detailed explanation.

If you're flying IFR, the answer is the same except you would be in contact with ATC either before or right after take off. The Class B becomes more or less moot - they handle it for you.