What Blackbird variant is the one at the Kalamazoo Air Zoo?

The Air Zoo refers to it as an SR-71B.  Their image of it shows it in NASA livery as NASA 831. This was originally USAF serial number 61-7956 which was one of two SR-71's built as trainers. 61-7957 was the other and it was destroyed in a crash in 1968.  They were both built as SR-71B's, not A-12's or YF-12's.

Number 956 was transferred to NASA in 1990 when the AF retired the SR-71's the first time. NASA labeled it as #831.

There is only one other dual-control trainer and it is an SR-71C, serial number 61-7981 which replaced the destroyed #956.  It was made from parts of the static test model SR-71 and the aft section of YF-12A #06934.

More info at Habu.org.


What are those arrow markings on the wing?

They are the overwing exit markings. You can see them in full in the following photo.

Boeing 737 Max overwing exits. By Oleg V. Belyakov - http://spotters.net.ua/file/?id=110706&size=large, CC BY-SA 3.0, Linkec

This is because as already noted in another answer, B737 does not have self inflating slides for its overwing exits and as such, the passengers need some guidance for exiting, to prevent them from going the wrong way.

Pessini

The above image shows the procedure for using the overwing exit.


How are missiles attached/detached from a combat jet aircraft?

AIM-9 Sidewinder and AIM-120 Scorpion are mounted on LAU-7 or LAU-127/8 launchers, known as "rails".
Upon signal from the pilot, the motor fires. The missile goes forward.
The umbilical cable connecting the missile to the launcher breaks away as the missile moves forward.
As far as how they're held on, there is a spring loaded lock mechanism, that is overcome by the missile motor.
pg 3-22 here:
https://www.globalsecurity.org/military/library/policy/navy/nrtc/14313_ch3.pdf

DETENT,  DETENT  LOCK,  DETENT-LOCKSOLENOID, AND SNUBBERS.—The detent, detentlock, detent-lock solenoid, and forward snubbers (fig.3-18) make up an  electromechanical system that restricts longitudinal and lateral motion of the mounted missile. This system prevents accidental launch or release during catapult takeoff or arrested landings. A slotted detent wrench/safety pin is installed through the mechanism assembly to prevent movement of the aft detent and to safe the launcher firing circuits. It is also used to raise the aft detent lug sufficiently to clear the missile  hanger  during  loading. The  slotted  detent wrench/safety pin is removed before flight. When the detent is down (normal), the striker points make contact with the buttons (contacts) on the forward hanger of the missile. The forward striker point does not have a function for the missile; the aft striker point makes contact between the missile and the firing safety switch

Body mounted missiles such as an AIM 7 or AIM -120 on a F-15 are kicked out away from the fuselage a couple of feet before the missile motor activates. There is a long cable that breaks away once the missile starts to leave.
The ejector foot is actuated by a small explosive charge.


How can I calculate the glide time for a B737 with engine failure?

For reference consider TACA Air Flight 110, a 737-300 that lost both engines at FL165, on approach to New Orleans in a very heavy hail/thunderstorm.

No exact listing of how long 110 stayed in the air with no power, but the Mayday/Air Disasters show on this incident hints that it was in the vicinity of 13-15 minutes, which indicates a drop rate of around 1100-1300fpm.

A heavier example was BA flight 9 a 747 that lost all four engines due to flying into a cloud of volcanic dust at night at FL370. This led to the classic announcement:

Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get them going again. I trust you are not in too much distress.

Fourteen minutes later at FL135, they got a restart. At that descent rate, they would have had maybe another nine minutes before hitting the ocean.


How and when is a VFR flight plan closed when flying from the US to Canada?

You should not need to call two different agencies to close your VFR flight plan. Call the nearest ATC unit, FSS (or a FIC) or a CARS is the appropriate action except IFR flights to an aerodrome served by a control tower or FSS where you are not required to file an arrival report unless requested to do so by the appropriate air traffic control unit (CAR 602.77 (3)).

Section 3.12 of the Transport Canada Aeronautical Information Manual (AIM) echoes the regulations from CAR 602.77 (1) and states:

  In order to comply with CAR 602.77, an arrival report for a flight plan shall be submitted to an ATC unit, an FSS (or a FIC) or a CARS as soon as practicable after landing but not later than:

  (a) the SAR time specified in the flight plan; or

  (b) where no SAR time is specified in the flight plan, one hour after the last reported ETA.

This idea of reporting to the closest unit is also supported by ICAO Annex 2 (Rules of the Air), standard 3.3.5.3:

  When no air traffic services unit exists at the arrival aerodrome, the arrival report, when required, shall be made as soon as practicable after landing and by the quickest means available to the nearest air traffic services unit.

Perhaps what is missing from the AIM/CARs is the idea that an arrival report should be filed with the closest ATC unit, FSS/FIC, or CARS. This is because the country receiving the flight (Canada in this case) becomes responsible for alerting services at destination (since it's located within a Canadian Flight Information Region). This concept aligns with the standards in ICAO Annex 11, standard 2.10.1:

  Flight information centres shall be established to provide flight information service and alerting service within flight information regions, unless the responsibility of providing such services within a flight information region is assigned to an air traffic control unit having adequate facilities for the discharge of such responsibility

I can't explain why 1800WXBrief would have seen the flight plan "closed" after a few minutes but responsibility for it would have indeed been delegated to Canada after departure. This might appear as closed to them in their system.

The call your FBO received from NAV CANADA was likely from FSS or the nearest flight planning office at the Area Control Centre asking whether you had arrived since they had an open flight plan for alerting services. Once the FBO notified them you were safe, they likely closed the flight plan.


What is the fuel temperature in the tanks during a flight?

Quite cold, in fact.  External air temps at altitude reach -30 to -40 deg C.  The fuel in the tanks wil cool down and reach those temps within a couple of hours exposure.  Jet A has an icing inhibitor added to it to prevent freezing of the fuel in the tanks during extended periods in the stratosphere.

From a heat transfer standpoint, I would probably analyze this as a rectangular bar made from a composite sandwich of aluminum with a Jet-A center subject to convective cooling by air moving at a typical true airspeed, say 450KTAS at STP for FL250.  For simplicity we would ignore compressibility effects.  That may be where you erred.


How fast can an airliner (like a Boeing 747) taxi backwards?

From a pure theoretical standpoint, the speed limit would be whatever rolling speed can be achieved with max reverse thrust. If you deployed max reverse on a landing, and left the max reverse on until you stopped, then released the brakes and left it on as you started to roll backward, you would accelerate backwards, and if you were able to maintain steering control (unlikely) and the engines were able to operate with the turbulent reverse inlet conditions without stall/surge, you'd accelerate until there was no longer any surplus reverse thrust.
You'd eventually be careening along backwards along the runway at, maybe 30kt, 50kt, 80kt... who knows? You could probably estimate some number based on available thrust and rolling friction/air resistance, but safe to say it's never been tried, or even thought of.  Don't even think of touching the brakes once rolling backward with any velocity.
From a practical standpoint, some operators may allow backing up under reverse thrust in specific circumstances, keeping in mind that you can't see where you're going so people need to be outside to clear the area behind, debris is being stirred up and ingested into the engines (ramp areas are a rich source of luggage zipper tags), and there's the problem of stopping without tipping over onto the tail when braking (the airplane's loaded C of G is not that far ahead of main gear, so it won't take much braking force for inertia to lever it over; safer to use forward thrust to stop than brakes).
So you may see power-back operations in the right circumstances, but the maximum speed in such cases won't generally be faster than a walking, (or maybe jogging) pace.


What's that rattling noise from parked jets?

It's fan or compressor blades rattling loosely in their blade roots as the engines windmill in the breeze.  The blades are attached to a hub or disc, and the retaining systems for the blades have to allow for thermal expansion, and also allow for a little bit of sideways compliance as the blades spin around, so they are a loose fit when cold.  Compressor blades are usually in a kind of interlocking socket and fan blades are often mounted on pins that allow a bit of freedom of movement.


Is this angle of attack animation backwards?

Maybe, depending on your interpretation.
The animation leaves room for interpretation. It is never specified what remains constant and what changes throughout the animation. For example, is the animation just zooming in on the sensor (and the sensor vane movement is just the entire aircraft pitching), or is the sensor picture relative to the aircraft pitch? Let's assume the latter; in the former case, it's obviously correct but doesn't teach us anything.
Climb/descent interpretation
The aircraft pitch displayed is the actual aircraft pitch as it is in flight. This means that respectively the situation in climb and in descent is shown. This makes sense with the preceding comments about the vane "being stuck in the climb position". In this interpretation, the animation is correct.
As the plane climbs, the thrust vector has a downwards component. This means the aircraft thrust accounts for part of the gravity, and the wings have to take less of the aircraft's weight. This means the angle of attack is reduced in climb, and indeed the sensor vane will point more 'down' during climb, and more 'up' during descent.
Angle of attack interpretation
The pitch shown in the animation corresponds to an angle of attack (i.e., the air mass is moving strictly horizontally through the animation). In this case the animation is incorrect.
A high angle of attack means that the air has a vertical component w.r.t the aircraft body; specifically, from the belly upwards. The AoA vane is like a weathervane, and will follow this movement. In a high AoA situation, it will point up (in a cobra maneuver, it would point straight up). This is opposite from the animation.


Do airlines have contingency plans to keep passengers warm in the event of an Arctic emergency landing (or otherwise a diversion)?

Taking FAA/USA as an example.

For north of 78th parallel, FAA operations are conducted in compliance with several regulations, including: FSIMS 8900.1, vol 3, Chapter 18, Section 4  Part B Operations Specifications: OpSpec B055 - North Polar Operations. The alternate airports must be able to receive the passengers of the diverted aircraft and to take care of the "physiological needs of the passengers and flightcrew for the duration until safe evacuation".

B055 requires the operator to demonstrate a recovery plan to extract passengers from a diversion airport prior to conduct commercial passenger operations. While it's the operator responsibility to provide the details, the general requirement answers your question:

  A recovery plan is required that will be initiated in the event of an
  unplanned diversion. The recovery plan should address the care and
  safety of passengers and flightcrew at the diversion airport, and
  include the plan of operation to extract the passengers and flightcrew
  from that airport.

As the plan should address the care and safety of people at the alternate airport, any protection against low temperature must be provided in order for the plan to be accepted by FAA. The plan must also demonstrate the ability to extract passenger from the airport within, if possible, 12h (which may be a challenge in Arctic region) and at most within 48h.

Extract of B055 (also discussed at PPRuNe, some copy-paste done from here):

Minimum Equipment List (MEL)

  Before receiving FAA authority to conduct polar operations, the MEL must indicate that the following systems/equipment is required for
  polar operations dispatch:

  3)    Communication system(s) relied on by the flightcrew to satisfy
  the requirement for effective communication capability.

  4)    Except for all-cargo operations, expanded medical kit to
  include Automated External Defibrillators (AED).

Training Program Requirements

  The following must be in the approved training programs:

  Training on special considerations, such as diversion decision making into austere airport environments to include aircraft
  performance, crash, fire, and rescue availability, and passenger
  support; and
  Flightcrew training in the use of the cold weather anti-exposure suit.

Special Flightcrew Issues for Long-Range Operations

  The operator needs to address the following special long-range
  flightcrew issues:

  A minimum of two cold weather anti-exposure suits will be required to be onboard so that outside coordination at a diversion airport with
  extreme climatic conditions can be accomplished safely.

Dispatch and Crewmember Considerations During Solar Flare Activity

  The operator must be aware of the content of AC 120-52, Radiation Exposure of Air Carrier Crewmembers, and provide crewmember training
  as stated in AC120-61, Crewmember Training on In-Flight Radiation
  Exposure.

En Route Polar Diversion Alternate Airport Requirements

  Operators are expected to give definition to a sufficient set of alternate airports for polar diversions, such that one or more can be
  reasonably expected to be available in varying weather conditions.
  The flight must be able to make a safe landing, and the airplane maneuvered off of the runway at the selected diversion airport. In the
  event of a disabled airplane following landing, the capability to move
  the disabled airplane must exist so as not to block the operation of
  any recovery airplane.

  In addition, those airports designated for use must be capable of protecting the safety of all personnel by being able to:
  (1) Offload the passengers and flightcrew in a safe manner during
  possible adverse weather conditions;
  (2) Provide for the physiological needs of the passengers and
  flightcrew for the duration until safe evacuation; and
  (3) Be able to safely extract passengers and flightcrew as soon as
  possible (execution and completion of the recovery is expected within
  12 to 48 hours following diversion).

Validation Flights

  An FAA-observed validation flight is required in which the operator exercises its reaction and recovery plan in the event of a diversion
  to one of its designated en route polar diversion alternate airports.
  The exercise of the operator’s reaction and recovery plan may also be
  completed prior to the validation flight.


I like the X-15, it was certainly an amazing airplane, but the truth is there were few benefits to the space program from the X-15.  It was far from a critical or necessary step:

The Mercury space suit was a direct derivative of the BF Goodrich Navy Mark IV, which had been in use for years. It wasn't developed for the X-15
The rockets used in the space program were completely different from the X-15. They were orders of magnitude stronger for one thing, used different fuels and completely different designs. Throttle-able rocket propulsion systems weren't new
The X-15 thermal protection system was of no use to the space program, which had to deal with far higher temperatures

There were some benefits:

It was a good source of astronauts: several pilot from the program went on to the NASA programs, including Neil Armstrong
Data from the X-15 missions were used in the X-20 Dyna Soar spaceplane which never flew, but it eventually morphed into the space shuttle

As to why didn't the Soviets make one, they didn't need it. Their manned space program built off of their ICBM development efforts which were successful. If the US hadn't built the X-15 the manned space program would most likely never gone the space shuttle route, but that wouldn't have been any sort of deal breaker.


Is there a requirement for self-locking / positive locking electrical connectors for aircraft systems?

EDIT: Note that the original question, which this answer primarily addresses, did not specify electrical connectors.
The FAA does provide regulations which at least partially cover this subject, though the guidance is rather broad.
The airworthiness standards in 14 CFR 23.607 for normal, utility, acrobatic, and commuter category airplanes stipulate that:

(a) Each removable fastener must incorporate two retaining devices if the loss of such fastener would preclude continued safe flight and landing.
(b) Fasteners and their locking devices must not be adversely affected by the environmental conditions associated with the particular installation.
(c) No self-locking nut may be used on any bolt subject to rotation in operation unless a non-friction locking device is used in addition to the self-locking device.

Likewise, the  airworthiness standards in 14 CFR 25.607 for transport category airplanes stipulate that:

(a) Each removable bolt, screw, nut, pin, or other removable fastener must incorporate two separate locking devices if—
(1) Its loss could preclude continued flight and landing within the design limitations of the airplane using normal pilot skill and strength; or
(2) Its loss could result in reduction in pitch, yaw, or roll control capability or response below that required by Subpart B of this chapter.
(b) The fasteners specified in paragraph (a) of this section and their locking devices may not be adversely affected by the environmental conditions associated with the particular installation.
(c) No self-locking nut may be used on any bolt subject to rotation in operation unless a nonfriction locking device is used in addition to the self-locking device.

As you can see, these regulations do prohibit certain types of locking fasteners in certain circumstances. For example, a nylon self-locking nut is not acceptable to fasten the exhaust manifold to the cylinder head; an all-metal self-locking nut would be acceptable, however.
The greater concern for a system such as a headset may be that to install it with fastening hardware—screws for example—would be to make it an installed part of the aircraft. The installation would then be subject to the various regulations of an installation: a log book entry, weight and balance considerations, etc.
Additionally, AC 43-13-1B, Ch 7, provides non-regulatory guidance regarding use of fasteners, including the use of locking and safety mechanisms. I will note that this guidance is superseded by manufacturer maintenance data for most modern aircraft.


Are solid fuel rocket engines designed differently and how?

Yes, solid fuel rockets are very different from liquid fueled rockets. A solid fuel rocket is basically some solidified rocket fuel and oxidizer wrapped in a non-combustible cylinder (hence the name). Once it's lit, there's no way to throttle it or shut it down, it just burns until all the fuel is consumed. On the other hand, in a liquid fuel rocket (cryogenic or not), liquid fuel and oxidizer are pumped into a combustion chamber to be burned. Liquid fuel rockets can be throttled or shut down by controlling the fuel pumps, and can be re-lit once shut down (assuming its igniter is reusable).

(It's important to note that the examples of "solid" rocket fuels you gave aren't actually solids. They're liquids, just like cryogenic fuels are. A solid fuel would be something like the ammonium perchlorate and aluminum powder used in the Space Shuttle Solid Rocket Boosters.)


What are the risks involved when doing a classic zero-g maneuver?

The biggest risk is improper execution.  If you build up too much airspeed and pull out of the dive at 4-G and break something, that will be your primary issue.

Your secondary risks will be associated with the fuel and oil system starvation if they depend on gravity for operation.  This risk is balanced by how long you can sustain 0-g flight.  Oil issues are bigger risk than fuel, as even if you did sustain 0-g long enough to starve the engine, you should get it back as soon as you are in positive G.  This particular risk will vary by airplane and I probably can't say something as general as "not typically a problem for short duration 0-g excursions".

An additional secondary risk is unsecured objects in the cockpit.  This presents a number of possible complications:

floating objects may distract you from aviating
floating objects may break something (the example of a window in the cockpit would cause a major distraction for the remainder of flight)
Most importantly, this can change your CG which can have dire consequences if something heavy enough gets moved far enough.

I wouldn't put risk of stall too high on the list, because you should be doing this with enough altitude and in coordinated flight so a stall would just be a simple recovery.

As for whether this is an aerobatic maneuver, it is a lot like a departure stall but a botched recovery (pushing over to 0-g before the stall breaks) and only a passenger could say for sure what you were actually doing.

That leads into the last risk I can think of, and that is when your passenger deposits his/her lunch all over the airplane.  In 0-g that could get on the windscreen and obscure your vision.  Be careful!


Do IFR flight plans ever get rejected for operational reasons?

Generally speaking, the only reasons for which a flight plan would be actually rejected would fall under what you referred to as "errors or omissions". But, the operational reasons you cite might lead to an amendment to your flight plan (which the pilot would most likely receive as an amended clearance).

IFR flight plans filed electronically are rejected by the flight plan processing computer if the filer files an impossible flight plan. I would presume that a flight plan filed verbally or in person through ATC or FSS would also be rejected for the same reasons, probably by the same computer, but with the rejection relayed to you through the third party. See these rejection examples that AOPA lays out in this article:

  If you plan a "direct" flight, point-to-point, follow the rules and
  enter the correct equipment. For example, if "/G" (or "slash Golf,"
  meaning that your airplane is equipped with an IFR-approved GPS and a
  Mode C transponder) or "/I" (you have loran or VOR/DME and a Mode C
  transponder) are not entered for these kinds of flights, the air
  traffic control computer will reject your flight plan because that
  route can't be flown with less capable equipment.

and,

  File fixes that are actually on
  the airways that you file in your IFR flight plan. Pilot error causes
  flight plans to be rejected when the filed points are not on the
  routes that are filed.

Depending on how you file, other possible rejection reasons might include formatting errors, a non-existent clearance limit, or might depend on the specific filing means; I am certainly not familiar with all means of filing. I have filed in person with a sheet of paper when standing in the office at the bottom of a control tower, over the phone, and online, and over the aircraft radio; I've never had an IFR flight plan actually rejected.

Beyond such reasons, a flight plan will typically not be rejected as such, but may well be amended. The reasons you propose—traffic density, route issues, etc—are usually negotiable, or are circumvented by amendments to your clearance. Certainly, these issues may present challenges, but they can usually be worked around.

These flight plans do receive scrutiny; IFR clearances are all about traffic separation, and this is ATC's primary task. Understand that to file an IFR flight plan is, essentially, to apply for a specific routing for specific time frame; you may or may not be given your requested routing when you receive your actual clearance. Receiving a clearance different from the route filed, or receiving a clearance amendment while en-route are both common. Note that an amendment need not be ATC initiated: the pilot can request an amendment, either before or during a flight.

One final note on TFRs: you can sometimes (often?) fly through these, even under VFR; you just have to get approval. For example, I've flown through the Grand Forks TFR while flying VFR with ATC approval.


What does "Request Boxing Vectors" means?

Boxing vectors is not a standard term. I can't tell you exactly what was going through the mind of the pilot (you would have to ask them directly), but based on your description, my interpretation would be that the pilot was requesting delaying vectors to give them time to work checklists. It is pretty common in an emergency situation where the pilots need time to evaluate the situation and plan their actions to request either a holding pattern or vectors around the airport. Boxing vectors could refer to the pilot wanting to be put "in a box" of airspace and left there until they had had time to figure out the gear issue. That would be my guess if a pilot requested boxing vectors on the frequency (although I would ask them for clarification of course).

In an emergency situation, the pilots don't really care where they are going (as long as they stay relatively close to the airport) so it makes sense to let it be up to ATC to decide. ATC then has the opportunity to move the flight to a quiet piece of airspace where they are not in the way for other traffic and let them run the checklists. It's a way for the pilots to reduce mental workload, as all they have to do it punch in a new heading every few minutes, instead of calculating and setting up an holding pattern in the navigation computer.


Generally the FAA inspectors are supposed to complete their EIR within 75 days of the date they learn of the violation, and regional review should be completed 15 days after that - so you should theoretically hear something from them within 90 days of a violation.

The NTSB's rules of practice governing certificate actions (referenced in that same FSIMS order - 2150.3B) says they can't suspend or revoke your certificate if the violation took place more than 6 months prior to their notifying you (the "stale complaint rule") so generally if you haven't heard from them after 6 months you're probably in the clear and won't need your ASRS stub anymore, but there are exceptions to this that are easy for the FAA to leverage, so holding on to the stubs longer isn't a bad idea.

Personally I believe in holding on to the ASRS stubs forever - I have mine (all 3) in a folder in the back of my filing cabinet, even though the newest one is almost 3 years old now and I'm fairly sure the FAA doesn't care about any of them, but if they do come after me for any of those incidents I know I did the right thing and I can prove it.

More importantly for me though it's a reminder that the point of the ASRS program isn't to be a get-out-of-jail-free card for when we screw up: That's the carrot used to entice us into filing them, but these reports are supposed to serve as an educational tool for other pilots and for us.
Any time I feel the need to file another ASRS report I take the time to look at the ones I filed previously - If I'm making the same mistakes multiple times that's a clue that I should be getting time with a CFI and working on those areas of operation.

Knowing my insurance policy on those incidents is still good if someone dredges them up later is just a bonus, and the stubs don't take up that much room.


During instrument approach, is an abbreviated racetrack course reversal allowed?

Unless you were "cleared straight-in" for the approach, when IMOMY is your IAF (as it was in this case) you are required to fly the course reversal, even if you can execute a direct entry. This is because the approach does not have terminal arrival areas labeled NoPT. So, yes, it was appropriate to fly the 6nm reversal.

That said, no, you cannot choose a different course reversal, even a shorter distance hold. When a hold is depicted in lieu of a procedure turn (HILO) you are required to fly the hold as shown.

AIM 5-4-6 (4) states:

  If proceeding to an IAF with a published course reversal (procedure turn or holdinlieu of PT pattern), except when cleared for a straight in approach by ATC, the pilot must execute the procedure turn/holdinlieu of PT, and complete the approach. [emphasis mine]

The IFH that you cited in your question has similar wording:

  For a hold-in-lieu-of PT, the holding pattern direction must be flown as depicted [emphasis mine]

Occasionally ATC will act surprised or get frustrated with you for flying a reversal when you're within a 90° turn of the initial segment's course, but unless they specify straight in you're doing the right thing.


Is it possible for the Boeing 737NG to do a powerback?

Possible? Yes! But not recommended.
There is nothing technical that would stop you from doing it. Thrust Reversers can be selected any time on the ground and there is enough thrust available to move the aircraft backwards. It is also not technically prohibited to do so:

Reverse Thrust
Intentional selection of reverse thrust in flight is prohibited.

(Boeing 737 NG FCOMv1 L.10.8 - Limitations - Operating Limitations)
There is nothing mentioned here that would prohibit the use of thrust reversers to back the aircraft. For comparison, on the Boeing 747 it is prohibited:

Reverse Thrust
Intentional selection of reverse thrust in flight is prohibited.
Backing the airplane with use of reverse thrust is prohibited.

(Boeing 747-400 FCOMv1 L.10.7 - Limitations - Operating Limitations)
Boeing does however not recommend using it on the 737 NG:

Backing with Reverse Thrust
Backing with reverse thrust is not recommended.

(Boeing 737 NG FCTM 2.4 - Ground Operations)
That is all the training manual has to say about it.

I do not know if backing with reverse thrust is actually done anywhere in a 737 NG. It was for sure done in older 737-100/-200 models:

When I flew the B737-200, we were trained in powerbacks, with SOPs set out, but it was to be used only as a last resort. I did only two during my time on the B737. On both occasions, we arrived in the US in a gravel equipped B737 that had a different nose wheel and their tow-bar would not fit.

(airliners.net)
It is also still being done in Boeing 757s:

(YouTube)


If the pilot cabin loses pressure, can the pressure difference lock the cockpit door?

Firstly: Flightdeck doors are to the best of my knowledge not hermetically sealed.

Secondly: Doors will normally have one of several solutions employed to safely handle explosive decompression:

Some doors have panels that pop out to equalise the pressure, especially inwards.
Some doors unlock automatically in one or both directions.

Needless to say, you need one solution in either direction. Whatever pressure difference there is it will most probably very quickly be equalised and there should not be any difficulty in opening the door if need be.


Aircraft power curve
(a.k.a “polar”—a completely illogical name because somebody long ago plotted them in polar coordinates, which makes no sense, but the name stuck)
This is just the power balance of the aircraft: the power provided by the propulsion system minus the power taken away by drag.
You can divide the values by velocity (true airspeed) to get a force (thrust - drag) curve instead. But usually just the power curve is plotted and lines through origin are used to read the interesting force maxima.
Two useful observations can be made about meaning of the power and force here:

Excess power is linearly proportional to sustainable climb rate, simply by $P = m g v_v$ (where $P$ is power, $m$ is mass of the aircraft, $g$ is gravity and $v_v$ is vertical velocity).

Excess thrust is linearly proportional to sustainable angle of climb. Well, actually there is some tricky trigonometry involved, but at low angles (non-aerobatic aircraft only do very shallow climbs and descents, below about 10°) you can approximate $\sin x \approx x$ and $cos x \approx 1$ and say that $T = m g \gamma$ (where $T$ is thrust, $\gamma$ is flight path angle and $m$ and $g$ as above).

This is true independent of what kind of propulsion, if any, the aircraft has. Power curves work the same for propeller, jet and rocket aircraft and gliders alike. Just the function describing power available for given speed differs by the propulsion type.
Kinds of power
A propulsion system is a device that converts one form of energy to another with some efficiency. So in has input power ($P_{in}$)—which is the rate at which energy comes in—and output power ($P_{out}$)—which is the rate at which it provides the desired energy. They are related by efficiency ($\eta$: $P_{out} = \eta P_{in}$). The rest of the energy—because energy is always conserved—is wasted (often as heat, but in aircraft propulsion the energy given to the reaction mass, the air, is also wasted).
Powered aircraft usually use internal combustion engines consuming hydrocarbon fuel, so the input energy is fuel flow times heating value of the fuel.
The output power of the whole propulsion system is then the energy given to the aircraft (to replace the energy taken away by drag), and this is always thrust times velocity. They are related by the propulsive efficiency, which varies with velocity, and varies differently for different propulsion systems.
When propeller is used, you can split the system in two parts, with their own separate efficiencies: The engine burns fuel, drives the shaft, and wastes the rest of energy as heat of the exhaust gases. It's output power is the torque times shaft speed (the RPM). The propeller then takes this power as input and accelerates some air to produce thrust. But doing so it has to sacrifice some energy to that air (its kinetic energy increases), so its output power is lower than that of the engine.
Note to units

Power=force x velocity, and we can apply that in different ways. If we were talking about electricity we could say Power is measured in Watts, and Watts= Voltage x Current. Because we are talking about prop aircraft, we should use a power unit like HP (for reciprocating engines). HP= Torque X RPM.

Power is always the same dimension, and therefore its basic unit is always Watt. This is a derived unit composed as $\mathrm{W} = \frac{\mathrm{J}}{\mathrm{s}} = \frac{\mathrm{kg}\ \mathrm{m}^2}{\mathrm{s}^3}$. Power is voltage times current for electricity, and the units work out, because $\mathrm{V}$ is just $\frac{\mathrm{kg}\ \mathrm{m}^2}{\mathrm{A}\ \mathrm{s}^3}$ (and Ampere is a base unit).
For fuel, power is heat value, in $\frac{\mathrm{J}}{\mathrm{kg}}$, times flow rate, in $\frac{\mathrm{kg}}{\mathrm{s}}$ and we are at Watt again.
And of course torque in $\frac{\mathrm{kg}\ \mathrm{m}^2}{\mathrm{s}^2}$ times angular velocity in $\frac{1}{\mathrm{s}}$ gives you Watt again. (watch out here; it requires angular velocity, in radians per second, not revolutions per second, but radian works as dimensionless here (metre per metre), so this is prone to error by $2\pi$ that dimensional analysis won't catch).
A horsepower is not an independent unit, just a funny multiple of Watt. Multiple different multiples of Watt, actually, because there are some variants.
Engine power as function of velocity
Piston engine power grows with RPM, then plateaus (at the expense of declining efficiency) and then you hit the maximum permitted RPM.
A constant speed propeller allows running the engine at the optimal RPM, and it's efficiency only decreases slowly with airspeed. Therefore a piston engine with constant-speed propeller produces relatively constant power over the design range of the aircraft, while the thrust declines about inversely proportionally to velocity. Thus it makes most sense to give power as the main figure describing it.
With fixed pitch propeller, you are limited by not being able to reach the optimal RPM at low speeds, and by having to throttle the engine to avoid exceeding the maximum RPM at high speeds, so the power declines faster as you get away from some optimal design speed. That's why fixed propellers are only used on slower planes where it does not matter that much. The power curve is still flatter than the thrust curve (dividing by velocity), so it still makes more sense to give power as the main figure though.
With turbojet engines on the other hand the available thrust remains roughly the same. It first declines with speed somewhat similarly to a propeller, but then the ram pressure starts increasing the effective pressure ratio and the available thrust starts growing again. That's why jet engines are generally rated with thrust, not power. But it isn't really constant over speed, just like the power isn't really constant for a piston engine and propeller.
And this carries over to turbofan engines, that are actually somewhere between. Their thrust decreases with speed, though slower then for propellers, and their efficiency increases. It is an oversimplification to rate them with just static thrust, but it remains the primary value given.


What is the difference between an aircraft main battery and standby battery?

Depends on the aircraft.

In most piston driven aircraft, the main battery is there for starting. The main battery also sort of runs all electrical equipment, lights and avionics. The only thing it does not run is the ignition system of the engine. I say “sort of” because the alternator supplies the battery and aircraft with more than enough electricity to supply the aircraft’s needs and recharge the battery simultaneously and at a slightly higher voltage. If the alternator goes out, it should not interrupt the total supply of electricity to the aircraft systems.

Think of the battery as a bucket with a hole in it, placed under a faucet (the alternator/generator). As long as the faucet is open enough to supply more than the bucket needs to remain full, you are getting all of the faucets water. If you partially or fully close the faucet, you are only going to get the water that comes from the bucket. But, your water flow is never completely interrupted.

On the other hand, the standby battery is a separate, isolated supply of electricity. As long as the main battery/alternator combination is supplying electricity, the relay is self supporting to keep the circuit closed to supply electricity from the main battery to the aircraft’s Bus Bar (electrical connection to the aircraft’s systems). If the main battery/alternator combo is not supplying electricity because it is dead, the relay will open the circuit from the main battery. It will simultaneously close the circuit supplying electricity from the standby battery to the Bus Bar. This would happen if the alternator/generator was offline or inop long enough to drain the battery.

The relay is probably a spring and electromagnetic set up. The state of being ON makes the main battery active. The state of being OFF makes the standby battery active.

Think of it like the faucet and bucket in the previous example, if the bucket were attached to a spring loaded shut off valve for another faucet. That second faucet was being fed by a container of water. It also had a hose bypassing the bucket. Once the bucket became light enough, the second faucet would turn on to supply you with water. At least, temporarily in a no water emergency.


Why does flying inverted in a jet trainer starve the engine of fuel when there's a pump?

I find it hard to make a general answer since the fuel systems could be different between various aircraft, but, according to Jan Roskam's Aircraft Design series (I just had to return the book, but I think it's Part IV in the series) some model of the F/A-18 utilizes the following system which, in sustained inverted flight (or any sustained flight condition wherein the aircraft does not experience a positive load factor), would eventually starve the engine of fuel.  Keep in mind too that fuel isn't the only factor for sustaining this flight condition: oil flow through the engine is typically gravity fed (reference for that is an engineer from Bell Helicopter who worked on the V-22 powerplant).  Suction is used to scavenge the oil out of the engine/gearboxes/etc, but the flow of the oil up to a point where suction will pull it out is via gravity (or whatever acceleration the aircraft is experiencing).  Hence, not only do we need to provide fuel, but we also need to provide for proper oil flow as well.

Anyhow, the F/A-18 fuel system.  Again, I wish I had the image from the text to show you, but the basic idea is this: if you had a flop tube capable of scavenging from the entire fuel tank, it would engender more problems than it solved.  Hence, inside of the primary fuel tank there's a second, smaller tank.  This tank has a series of poppet valves that allow fuel to flow into the inset tank during coordinated (i.e., positive load factor) flight.  When the aircraft is not experiencing a positive load factor, the pressure of the fuel on these valves holds them closed and the fuel stays within the inset tank.  A short flop tube within this space provides fuel to the engines for the duration of the maneuver.  However, as noted, this inset tank is only a portion of the larger main tank, so its capacity would be some fraction of the main tank, limiting the duration of the maneuver.

So, to answer your question (how does fuel starvation happen and why isn't it solved via a pump) it's a design problem that, per the printing of that text, could not be solved by adding capacity to the pump.  There just simply wasn't fuel present at the fuel sump to be scavenged.  The real design problem would lie in the design of flop tubes capable of scavenging from the entire tank without creating more design problems (an assumed point on my part).  Examples, I think, would crop up if you decided to make a multiplicity of flop tubes (larger pumps required, more parts, more complex plumbing, etc.), or longer flop tubes (potential risk for damage to the tube head/tank with increased "flopping" inertia, larger pump required for greater head losses, etc.)...but I also don't know what the current standard is.


What is the lump under the English Electric Lightning's fuselage?

The lump is a ventral fuel tank, aka conformal fuel tank.

  The F.3A introduced [...] a new, non-jettisonable, 610-imperial-gallon (2,800 L) ventral fuel tank.—Wikipedia


What is the distance at which my VHF communication radio can reach ATC?

The TKM MX11 has an 8 watt transmitter which makes it a Class 4 transmitter as defined in RTCA DO-186B MOPS for Airborne Radios Communications Equipment. That specifies a maximum range of 100 miles.

In an area of relatively level terrain, you should see a range of about that 100 miles if you're at 5000 AGL or above. Below that, range will be reduced due to the curvature of the earth and multipath interference. At 2000 feet above level terrain, 40 to 50 mile range is typical based on an analysis I did about 20 years ago for a former employer.

One factor you can't control is the height of the ATC antenna.  The higher it is, the greater the range. Even a 50 foot difference in the height can affect the range by several miles.


Why would the cabin crew spray the cabin before landing?

The sprays are (usually) insecticides used to prevent the spread of invasive species and diseases.

  The process of ‘disinsection’ is required under the International Health Regulations of the World Health Organization (WHO) on flights to and from certain destinations to prevent infectious and contagious diseases carried by insects and other volatile bodies. Rules established by the International Civil Aviation Organization (ICAO) require that disinsection does not injure or cause discomfort to passengers or crew. These rules permit the use of certain insecticides, which have the approval of and are recommended by the WHO based on their effectiveness and safety.

From the US dept. of Transportation


Why would an aircraft drastically reduce in speed and then accelerate during landing?

Your question uses the adverb "drastically". It's very unlikely that whatever happened was drastic. When an airliner does something drastic, it's a pretty memorable experience. In the absence of visual cues, some other sensations can be magnified in our experience, so it's quite possible that any change was less extreme than it seemed to be.

Sometimes, the plane is actually slowing down and speeding up. This could be in response to an air traffic control instruction, a not-quite-right adjustment that needs to be corrected, changes in local wind condition and so on.

It could also be that the plane needed a little adjustment after intercepting the glide-slope.

At this stage of its flight, the crew many need to respond to many different kinds of factors in its environment.

However, just because you had sensations of speeding up or slowing down doesn't mean that that is actually what happened. Changes in pitch can also produce these sensations, especially when combined with changes in engine sound.

In short, if that did actually happen, it could be for all kinds of reasons, but just as likely, it was an illusion.


Please identify this twin-engine airliner


Why is the minimum runway length non-linear in relation to the landing weight?

While the kinetic energy is proportional to mass, it is not proportional to velocity.

The heavier the aircraft is, the higher the landing speed. So the stopping distance increases mainly because of the higher landing speed.

Comparing two landings, first at mass = $m_1$, the second at mass = $m_2 =1.1 \cdot m_1$, the landing speed will be $\sqrt{\frac{m_2}{m_1}}$ higher during the second landing.

The kinetic energy during the landing will scale proportional to the square of the mass.


Why did narrowbody jetliners take so long to switch over to high-bypass engines?

Early high-bypass engines were expensive and unreliable.

The effort in developing new technology and designs, plus the cost of building a larger fan add cost. Then all of the new technology is inherently less reliable than existing proven designs.

The JT9D was notoriously unreliable, causing major problems in the development of the 747. Development problems and spiraling costs from the RB211 bankrupted Rolls-Royce, had huge failure rates, nearly causing an accident (Eastern Airlines Flight 855), and ultimately killing the L1011. CF6 fan disk failures caused National Airlines 27, sucking a passenger out the window, and the fatal United Sioux City crash.

Even what we think of as the most reliable engine today, the CFM56, when new had a fan failure leading to a fatal crash (Kegsworth), combined with water ingestion issues that nearly lead to a crash (TACA 110).

When you have such compromised technology, you narrow it in the place that makes sense. High bypass engines brought high efficiency, reducing fuel burn. They also had more thrust, allowing heavier planes, carrying more fuel. Both advantages combine to enable long-haul direct flights which passengers like. These are flown with widebodies, so naturally these engines were used in widebodies.

Short-haul narrowbodies carry less fuel per flight, and can refuel frequently, so there wasn't an advantage here. Only as the compromises with high-bypass engines were solved, then did the technology trickle down.

You see a similar thing today with carbon fiber composite fuselages. They're expensive to build, expensive to fix, and there is uncertainty over long-term costs. But the weight savings opens up ultra-long-haul flights, hence the A350 and 787.


Why do some fighters have two engines and other have only one but still give the same performance?

Some countries don't get the most powerful engines and have to use what is available in the market. To avoid upsetting China too much, the US would not sell the F404 or the F100 to Taiwan, and a derivative of a civilian engine had to be developed.

A second reason is redundancy: When the US Navy had to decide between the F-16 and what was to become the F-18, they preferred the design with two engines, because losing your only engine over water is a much more life-threatening experience than losing it over land. Similarly, the Eurofighter was designed more for peace than for war - having two engines will reduce training losses.

Generally, a single, bigger engine will be more powerful and more efficient per unit of mass, because manufacturing tolerances will be relatively smaller in the bigger engine, if the same technology is used for both. Single engines need to have more system redundancy than one of a pair of engines, so some of that advantage cannot be transferred into the finished design. Nevertheless, from a performance standpoint the single engine fighter will look better.


What is the FAA definition of solo flight?

According to FAA, it means that the pilot should be the only person in the aircraft. According to 14 CFR § 61.51 - Pilot logbooks,

  (d) Logging of solo flight time. Except for a student pilot performing the duties of pilot in command of an airship requiring more than one pilot flight crewmember, a pilot may log as solo flight time only that flight time when the pilot is the sole occupant of the aircraft.

14 CFR § 61.8761.87 - Solo requirements for student pilots also says pretty much the same thing:

  (a) General. A student pilot may not operate an aircraft in solo flight unless that student has met the requirements of this section. The term “solo flight” as used in this subpart means that flight time during which a student pilot is the sole occupant of the aircraft or that flight time during which the student performs the duties of a pilot in command of a gas balloon or an airship requiring more than one pilot flight crewmember.


What is the required accuracy of an airspeed indicator?

There are two standards, one for traditional pitot/static devices and one for air data computers.
Traditional A/S indicators are covered by TSO-C2d which references Society of Automotive Engineers, Inc., (SAE) Aerospace Standard (AS) 8019, "Airspeed Instruments", dated March 30, 1981.
Air data computers are covered by TSO-C106 which references SAE AS 8002, “Air Data Computer - Minimum Performance Standard,” dated October 30, 1981.
The SAE documents must be purchased.
Accuracy in the AS docs is not stated as a simple value. And as the system depends on installation, the aircraft level standards are applicable.
For traditional A/S indicators, repeatability is more important as installation can add errors. The aircraft manufacturer typically provides an IAS to CAS table in the POH. Since Part 23 aircraft rules have moved to a functional standard (e.g., it has to do its job well enough to be safe), there's no specified accuracy.
For Part 25 aircraft where air data computers are the norm, they must meet 14 CFR §25.1323 Airspeed indicating system.


Which clearances are issued by ATC without the pilot requesting them?

No clearance is issued without the pilot requesting it. But a request is not just something you do on the radio. The interesting questions here is: how do pilots request something?

The most common way is through a flight plan. By filing a flight plan, the pilot details the planned flight, from departure to destination, via a predefined route, with a requested speed and level. ATC will issue a flightplan clearance prior to departure or prior to entering controlled airspace. This covers the general flight, and basically lets the flight take place.

During the flight, specific details need to be requested by the pilot - such as taxi - but only if the controller is not already aware that the flight is ready for whatever it is they are requesting. For example, during radar vectors for approach, ATC already knows that the flight is requesting approach at their destination (since the destination is noted in the flightplan), so ATC will clear the flight for approach without needing the pilot to explicitally request it. Same goes for landing clearance. The pilot does not have to explicitally say "request to land", because this is already a part of the flight plan. ATC will automatically issue a landing clearance when appropriate.

ATC can issue instructions or clearances to flights that deviate from their flightplan if needed for safety or efficiency reasons. For example, ATC may instruct a flight to change level due to traffic ahead on the same level. But the flight plan is always the basis for all clearances.


Cascading Wings: Do they really increase lift by 300%?

The software appears to be taking the net plan area or shadow area of the overlapping stack as its area, but is adding the individual lifts of each wing. If you add the individual areas too then the calculation should show a fall in Clmax due to interplane losses.
I'd call it a bug, however I do not know the software so perhaps it is a "feature". It depends on whether you regard your stack as one wing or four.


How does the safety record of a Cessna 152 compare to a jetliner in Europe?

I can't give an answer on this, but the reasons why are informative. General aviation as a whole has a higher accident rate than commercial aviation, at least in part because of the many varied missions, some of which are inherently higher risk, like:

Microlights
Homebuilts
Cropdusting

So the statistics aren't going to be very much to go on. Additionally as you mention it varies a lot globally, and there's variations for the type of flying, time of day and other factors. Focusing down on the C152 isn't going to give you a good figure because they are an extremely popular training airplane, which is a higher risk activity.

Basically you want to know what the accident rate is for a European Cessna 152 flown in the day by an instructor pilot for non-training purposes, there just isn't any data source for that. It's going to be pretty low I would imagine.


What special airspace exemptions are granted for civilian fighter jets?

The same regulations apply to civilian ex-military aircraft as they apply to any other aircraft. Whether flying IFR or VFR, you will need to comply with the same rules, e.g. speed restrictions, airspace restrictions when under VFR, meteorological conditions, etc.

An exception can be speed restrictions, where a speed restriction would be in contradiction with the parameters of the aircraft to perform safe flight, e.g. the minimum clean speed being above 250kts or similar.


What is that wing device that looks like a mini-spoiler on the CJ3?

I found a hint in a worldofaviation.com article; it's an "aileron fence":

... a small 'aileron fence' rises from the upper surface, just inboard of the ailerons.

Now knowing what to look for and the angles to consider, it's now much easier to spot (and to not spot—knowing that shallower head-on angles would not show it).

Source: wikimedia.org

Wikipedia's Aileron article says:

Aileron fences Some aileron designs, particularly when fitted on swept wings, include fences like wing fences flush with their inboard plane, in order to suppress some of the spanwise component of the airflow running on the top of the wing, which tends to disrupt the laminar flow above the aileron, when deflected downwards.

But, it's citation needed
As seen below, when downward deflected, the aileron actually takes the fence down with it, so Wikipedia gets it wrong.

Source: wikimedia.org; this high-res photo shows it attached to the aileron

There's little literature on the device; I was able to find only one source where it's properly explained and makes sense:

In the presence of a sideslip from the wingtip direction of a given aileron, the fence creates a local high-pressure area on the upper surface of the aileron causing it to deflect downward and lifting the opposite aileron. This causes a stabilizing rolling moment away from the sideslip. Fences can also be installed on the lower surface at the outboard edge of the aileron and function in much the same way to create a low-pressure area to “suck” the aileron down. Although aesthetically preferable, these are usually less successful. Some examples of aileron fences used for static lateral stability can be found on a wide range of aircraft: Cessna 206 (single engine piston), Cessna 208 (single engine turboprop), and Cessna Citation CJ3 (twin engine turbojet, Figure A-7).
— Williams, Russell Loy. Reduced static lateral stability in airplanes. 2005. (PDF)

Another thing Wikipedia gets wrong as shown by that thesis, is that it's present on three Cessna models with straight wings.


Are there any publically available recordings of conversations between ATC and pilots?

LiveATC.net has live and recorded ATC radio for most countries/airports.  There are lots of flight tracking websites, e.g. FlightAware, that have live and recorded radar/ADS-B tracks.  You'll have to correlate the two yourself.


Which engine manual must a pilot legally use?

FAR Part 91, in a certificated plane, private piot in a private plane, you can fly however you'd like.  Charles Lindberg taught lean of peak to pilots on WWII to save fuel for long distance ocean flights.

Check the engine manual, you will find you can fly as lean of peak as you can manage.  I find it hard to do with carburated O-360 engine. Usually I lean out until it gets rough, then enrichen some.  I just had a 4-channel engine monitor installed, so now I can start experimenting and see how well it really does LOP, maybe playing with some carb heat to help stir up the air flow better.
With fuel injection engines, you can adjust/swap out the injectors to get better fuel flow into each cylinder for better lean adjusting.

Leaning helps maintain good fuel/air mixture so you don't run too rich and waste fuel.  If you check later year Manuals, you may find better direction on leaning for your engine as well.  For the Cessna Cardinal, I have a 1977 POH that I use to supplement my plane's 1973 POH, Cessna got smarter as time went on it seems and some things are covered better.

Flying commercially may be a different manner. There the Company may specify one thing over another, you may not have a choice.


How is US Class B airspace enforced in Canada?

The portion over Canada is not designated US Class B but Canadian Class C.

Note that Canadian Class C airspace definition is similar to US Class B.  In particular,  VFR aircraft must obtain clearance prior to entry.  A mode C transponder is required.

To add: airspace over Canada is generally managed by NAV CANADA.  Definition for the Canadian side of the Detroit Terminal Control Area (TCA) can be found in NAV CANADA's Designated Airspace Handbook, portions excerpted below (from page 78):

We can see that these definitions matches the eastern portions of the Detroit TCA exactly, e.g, the outer area altitudes from 6,000' to 10,000' bounded 30nm from the Detroit VOR (DXO).

The Detroit TCA airspace was modified a few years ago, which required coordination between the FAA and Nav Canada.  The following discussion from the US Federal Register (page 3307) may be of further interest:

  Also, as noted in the NPRM, the
  eastern portion of the DTW Class B
  airspace area extends into Canadian
  airspace. The equivalent Canadian
  airspace to Class B airspace, as
  designated in the United States, is Class
  C airspace. NAV CANADA, the
  Canadian air service navigation
  provider, generally designates Class C
  airspace with a 12,500 feet MSL ceiling,
  however, has advised the FAA of its
  willingness to establish corresponding
  Canadian Class C airspace adjoining the
  FAA’s DTW Class B airspace with a
  ceiling of 10,000 feet MSL.
  Additionally, NAV CANADA advised it
  would make the Canadian Class C
  airspace action effective to match the
  effective date of this DTW Class B
  airspace modification action.


Cessna 172: at which RPM should the oil pressure reach the green arc?

Your answer will be elusive.  The problem is that oil pressure is a function of the oil, oil temperature, time, engine pressurized oil draw (the "wear" of the engine), and RPM.

I am confident a model could be created using the above parameters, and possibly one or two more.  However, you are probably not interested.

I have about 8000 hours of instruction given in C172M, which is a different engine.  With 100 weight oil, at 20C or higher, I teach that oil must be moving up within 5 seconds, and with 1000 RPM it must be approaching or in the green within 10 seconds or there is an engine shutdown.

In contrast, with 80W oil, at 32F (we require preheat if engine temp is below 32F and the aircraft is at home base), I teach that the oil pressure must be moving within 5 seconds and in the green within 15 seconds.

These times are on our customized checklist, and do not address cold weather ops although they are quite common for us.

We will not start taxi until the oil is in the green arc. We always look for movement of the oil gauge within seconds after the engine start. We bring the engine above 500 RPM, but not necessarily to 1000 RPM waiting for the oil to rise up.  A factor in not going to 1000 RPM immediately is that the engine wear without full flow on a journal bearing is the square of the surface velocity. On the other hand, the pump volume is nearly linear with respect to the rotational velocity.

Also, note that we use straight weight oil 90% of the time.  Multivis oil will behave differently.

To address your two questions, I propose you use the following:
-1000 RPM for oil check all the time

500 RPM idle typically yields 30 to 35 PSI


How does drag change with Reynolds number?

Recall the definition of the Reynolds number:

Where ρ is the density, v is the velocity, μ is the viscosity of air and l is the characteristic length.

The characteristic length is typically the chord length of an airfoil but can also mean the overall length of the airframe. When we scale down a model, we are decreasing l.

Decreasing l while holding all other variables constant (which I assume is what you meant about "forgetting to adjust the Reynolds number"), has the net effect of lowering your Reynolds number.

Looking at airfoil graphs for example, we can see the relationship between the Reynolds number and the drag coefficient of the body:

It is obvious from the graph that the drag coefficient increases when the Reynolds number is lower (higher curve on the graph)

Image source: Airfoil tools


Do the operations practices of low-cost airlines represent an increased safety risk?

We should not make statements about any particular airline. Air travel is and remains very safe, due to:

Good practices imposed by the regulatory institutions.
Feedback of things that went wrong in the past to prevent them from happening in the future.
Very mature engineering and technology implementation
Lots and lots of experience with reliability numbers over the decades.

That being said, proper procedures do need to be followed and it could theoretically be the case that only minimal maintenance is carried out at some airlines, while others are more pro-active and lead the field in safety practices. Think Rainman, and the airline that has never crashed.

Safety numbers of all airlines in the developed world are very good. Cheaper airlines must follow the same practices as more expensive airlines. The cheaper tickets are the result of better business practices, not of worse maintenance practices.

Edit

@Michael Kjörling points out a TV episode about a case of Madrid airport being closed, all traffic lining up for Valencia, and three RyanAir aircraft declare fuel emergency. Plus a LAN Chile declares engine out Mayday.

Don't know if this counts as evidence though, TV programs must find or produce a topic that is sensational enough for transmission. The safety numbers are still on RyanAirs side, their safety record is pretty good.


Need help identifying planes, near Toronto

The last one is almost undoubtedly a Pilatus PC-12 operated by Ornge.


What is the relationship between thrust and engine RPM in a turbojet?

First, lets see how thrust works. NASA explains it pretty good. They conclude that for turbo-fan engines "specific thrust [...] depends only on the velocity difference produced by the engine." If you think about it, velocity difference in a gas is dynamic pressure. So, how much thrust the engine will generate depends on how big of a dynamic pressure difference it can create in the air between its front and back. A turbo-fan engine creates this pressure difference in two ways. One is by using a fan to "push" air to the back. The other one is by heating up the air that passes through its burner and shooting it out of the nozzle (after passing it first from the turbine.)

Now, on to your question. We need to see if added RPM creates added thrust (or if more thrust needs more RPM.) The answer is that, yes it does. Providing the engine with more fuel will create faster escaping hot gasses from the burner. Those will create a bigger dynamic pressure difference between the burner and the nozzle and the turbine will turn faster. Power from the turbine is moved to the fan which will also turn faster thus pushing out more air.

Refer to here for a graphical description of the engine compartments and how pressure is formed between them.

How RPM and total thrust for a model turbo-fan engine are related is graphed on page four and seven of this document. There you can also find various equations that describe those graphs.

EDIT: A turbo-jet engine works pretty much the same but instead of using the power generated from the turbine to mainly move the fan, it uses it to move only the compressor. All its thrust is generated from the hot gasses coming out of the nozzle.


When flying a glider in emergency situation, would it be more safe to bailout or to land in a forest?

Thankfully, I never had to make this choice. In my training I learned to stay in the plane and flare at the height of the treetops, then let the plane sink into the branches and have them stop and suspend the aircraft. The fuselage is quite effective as a protective shell, and up on top the branches are thin and flexible.

Use the parachute only to hoist yourself down from the stricken plane, if necessary.

Two-seater after landing in trees at Boberg glider port (picture source)


What does "pitch plus power equals performance" really mean?

A.  It simply means that the airplane will perform according to the combination of pitch and power control inputs that you make.
B.  Yes, why wouldn’t it be?  Aircraft are subject to basic laws of physics.  These laws are consistent.  Every time you pitch nose down and add power you will descend and accelerate.  Every time.
C.  N/A because it is always true, but it is just a saying.  If you find the concept useful to enhance your understanding or explain something, then use it.  If not, then don’t.  Aviation is full of such sayings to help pilots remember things, like “aviate, navigate, communicate”, “ARROW” etc.  Pick the ones you find helpful and don’t overthink or try to discredit the ones that aren’t useful to you.


How can V1 and VR (rotate) speeds be calculated?

There is no general equation/function that you can use to calculate V1/Vr... the manufacturer test out the aircraft's performance during certification, and you then compare your current aircraft and conditions against the known manufacturer's aircraft and conditions to get your results.

V1 is the border between accelerate for takeoff, and STOPPPPPP! by the end of the runway.
* Acceleration is dependent upon the engine thrust being used, the atmosphere providing oxygen for combustion and nitrogen for jetflow mass, the aircraft's mass that has to be accelerated, the drag of the used flap setting, and the possible drag of the runway surface and slope.
* The STOPPP! aspect is dependent upon the drag of the flaps and speedbrakes, the drag of the runway slope and surface, and the mass of the airplane.

Vr is nothing to do with V1... it's just a margin below V2 (5kts? 10kts? depending on thrust setting) that allows you to rotate earlier than V2 but still accelerate (in the air) to then achieve V2 by 15m/50ft. And V2 depends on the weight of the aircraft and the flap setting.


Why are the center tank pumps deactivated when slats are extended on the A320?

You're right. But it's not because of the slats. It's because of what the plane is doing when the slats are being used.

The slat position is used in some system logic because it's indicative of a takeoff and approach. For example, on the MD-11 the engine ignition is automatically put into continuous mode when the slats are operated, because that's indicative of slow speed.

The same for the A320, slats extended means a takeoff / climb is about to commence, or the plane is on approach with a potential go-around.

Those conditions require high fuel pressure.

The center tank has 2 pumps, while each wing tank has 2 pumps. If a center tank pump fails, it will be 1 pump supplying 2 engines, compared to 2 pumps for each engine (or 1 for each in a rare double pump failure—one in each wing).

If a pump fails, there is no automatic command that can be sent to the sequence valves to change the sequence, or to engage the crossfeed valves.*

Usually the center pumps overpower the wing pumps, but what is omitted from that explanation is that there are sequence valves. If one center pump fails, the pressure may remain high enough to keep the valves closed on the good side, but not high enough to supply two engines during high demand.

Also note there is no suction (gravity) feeding from the center tank. I attached an A320 fuel schematic below, number 13 is the sequence valve.

RE: Why does not this apply to all aircraft?

The 737 Classic faced issues (see footnote). Other types have more than 2 pumps for the center tank, and/or have more powerful pumps. Another option is to use the center tank to fill the other tanks (like on the MD-11).

The 747-1/200 also required using the wing tanks during takeoff, see this answer by @Terry.

A speculation on my part, is that it was cheaper to certify the plane like that, or problems were found and that was the cheapest solution.

  A fuel tank that is not designed to feed the engines under all flight conditions need
  be tested only for the flight regime for which it is designed to do so (e.g., cruise conditions).

  (FAA Flight Test Guide For Certification
  Of Transport Category Airplanes)

* A fuel imbalance may quickly develop when each engine is consuming +70 kg of fuel per minute (an issue that affects the 737 Classic).

  On the classics, when departing with less than 1,000kg of fuel in the centre tank, an imbalance may occur during the climb. This is because the RH centre tank pump will stop feeding due to the body angle so number 2 engine fuel is drawn from main tank 2, while engine 1 is still drawing fuel from the centre tank. When this “runs dry” the scavenge pump will also transfer any remaining centre tank fuel into main tank 1, thereby exacerbating the imbalance.

(A320 FCOM)


What was the yearly number of MiG-15's produced?

There is hardly anything that can't be found with the help of a few friends and the Library of Congress. "Истребитель МИГ-15 (MiG-15 Fighter)" ISBN 9785857290194 Pp.52-57.

Plant No.1 (Kuibyshev):

             MiG-15    MiG-15bis    MiG-15Pbis     UTI MiG-15bis
1949 Plan    550
     Actual  510
1950 Plan    300       350                          50
     Actual  301       401                          50
1951 Plan              792         5               365
     Actual            820         5               371
1952 Plan              425                         315
     Actual            460                         333
1953 Plan
     Actual    2                                   127

Non-flyable [what the heck is that??] MiG-15: 2 in 1949, 4 in 1950.
10 knock-down UTI MiG-15 kits were produced in 1951.

Plant No. 153 - Novosibirsk

             MiG-15    MiG-15bis    MiG-15Pbis     UTI MiG-15bis
1949 Plan    550
     Actual  144
1950 Plan    300        500
     Actual  308        360
1951 Plan              1173
     Actual    1       1196
1952 Plan               840
     Actual             863
1953 Plan                                          200
     Actual               1                        209
1954 Plan                                          700
     Actual                                        715

Plant No.381 (Leningrad): 1949 - 75 MiG-15

Plant No.21 (Gor'ky):

             MiG-15bis (type 53)    MiG-15Rbis (type 55)
1950 Plan    350
     Actual  367
1951 Plan    937                     60
     Actual  992                     64
1952 Plan    395                    300
     Actual  425                    300

Plant No.31 - Tbilisi

             MiG-15bis (art. 50)
1951 Plan     30
     Actual   35
1952 Plan    190
     Actual  190

Plant No.126 - Komsomo'ls'k-NA-Amure

             MiG-15                 MiG-15bis
1950 Plan                           250
     Actual    1                     42
1951 Plan                           337
     Actual                         362
1952 Plan                           400
     Actual                         428

Plant No.292 - Saratov

             MiG-15    MiG-15bis    MiG-15Sbis
1950 Plan              275
     Actual    8?      131
1951 Plan              457          100
     Actual            509           49
1952 Plan              350
     Actual            354

Plant No.135 - Kharkiv

                UTI MiG-15
1950 Plan              25
     Actual             6
1951 Plan              50
     Actual            50
1952 Plan             150
     Actual            85
1953 Plan             150
     Actual           158
1954 Plan             200
     Actual           212

Plant No.99 (Ulan-Ude)

                UTI MiG-15
1951 Plan              75
     Actual            29
1952 Plan             125
     Actual            53
1953 Plan             150
     Actual           127
1954 Plan             200
     Actual           206
1955 Plan             225
     Actual           245
1956 Plan
     Actual           173
1957 Plan
     Actual           113
1958 Plan
     Actual           106
1959 Plan
     Actual            65

Totals for the USSR (may contain errors, haven't double-checked):

|      | Combat MiG-15 and variants |  UTI MiG-15   |
| Year | Plan          | Actual     | Plan | Actual |
| 1949 | 1175          |  729       |    0 |    0   |
| 1950 | 2325          | 1911       |   75 |   56   |
| 1951 | 3891          | 4033       |  490 |  450   |
| 1952 | 2900          | 3020       |  590 |  471   |
| 1953 |    0          |    3       |  500 |  621   |
| 1954 |               |            | 1100 | 1133   |
| 1955 |               |            |  225 |  245   |
| 1956 |               |            |    0 |  173   |
| 1957 |               |            |    0 |  113   |
| 1958 |               |            |    0 |  106   |
| 1959 |               |            |    0 |   65   |


Is there a 180HP conversion available for a 2011 160HP Cessna 172R with a Garmin G1000?

Not a solution, but I looked at this a couple years ago.  I have a 2005 172R G1000 in a flight school and students tend to go to the 180hp planes, so I looked into the upgrade.  I did find that Cessna did a STC for a limited, sequential group of Serial Number 172R G1000's.  I believe they might have been done for Embry Riddle, but not positive.  I actually found this out from FAA when I was calling them about a STC or Field upgrade.  Got to the same point as your e-mail string.
Bottom line - it has been done.  It can be done.
When I called Cessna about the details they did tell me the block of SN's it applied to, but after that they would not share anything.
After looking into this again today, talking to Air Planes (they are very nice, and they would love to be able to sell a kit for this!) and remembering my conversations - I think I'll do some digging again.  I'll post if I find anything
Mark - 191CA


All airplanes can glide, if they couldn't they wouldn't be able to fly in the first place. When you glide an aircraft you are converting height into airspeed, which you can use to move across the ground. How far you can go across the ground for height lost is called the glide ratio for the aircraft. Gliders have a very high glide ratio as their wings are designed to provide lots of lift at low speeds, fighters have a very low glide ratio as they are designed to provide lift at a much higher speed enabling the fighter to achieve high airspeeds efficiently.

So a fighter will glide, it just won't be able to glide that far over the ground. If a fighter has enough altitude to trade for speed and a strip close enough by it can be done (and has been done in the past) by a skilled pilot.


What is the longest distance at which an aircraft can be visually identified?

The key piece of information here is the "Angular Resolution" of the naked eye.

Is called in this way because the key parameter is the perceived angle between two points when looking at them. Let's take 2 points that are distant 1 meter one from the other.

Let's then put them at a distance from your eyes, the angle you see between them can be computed as follows:

Image source

$angle\_in\_degrees = 2*atan(\frac{distance\_between\_them}{2*distance\_from\_you})*\frac{180}{\pi} $

if they are 10 meters from you, they will appear about 5.7° apart
at 100 meters from you, they will appear 0.57° apart
1000 meters, 0.057° apart

Note that two dots 10 meters apart and 100 meters from you will appear with the same 5.7° of the dots 1 meter apart and 10 meters from you: this is why, if you do not have other references, is nearly impossible to understand the distance from you of an object.

Now you are interested in reading something, in particular the aircraft number.

The naked eye cannot distinguish two points that appear less than 0.0128° apart (bright day, with no haze nor warm air distortion)

From what we see above, if the lettering is 1m tall, you could distinguish it at about 4 km.
To actually read it, though, you will have to pick up the details, that will be much smaller: thik of distinguishing a "O" from a "D", you will have to notice that the left side is straight (or not), a detail much smaller than the total height of the letter and this will greatly reduce you maximum distance at which you can read.

Recognizing the livery instead is quite easier, as full portion of the aircraft will be painted, and in this case you only have to pick up the colours, not details of the shapes.

You could also distinguish the shape of on aircraft from a larger distance, given the much larger dimension of a full aircraft, but as for the letters, smaller details will not be recognizable until you get close enough, where "enough" depends on time of day, weather conditions and size of what you want to observe.


What is the difference between the WSUSnn IDs used in convective SIGMETs?

The WSUS31 is an WMO ICAO communications header. It is not a SIGMET category, it just identifies the basic item and source, in this case WSUS31 is weather-SIGMET united states, 3x is for regional distribution (eg the Americas) x1, x2, x3 are the east, central, and west SIGMET areas in the contiguous USA[CONUS].
Another example: An AIRMET for the far west area would be WAUS46. AIRMETs have 6 areas in the CONUS and 3 in Alaska, 4x means national distribution.
Distribution codes

0x,1x global
2x,3x regional
4x,8x national and bilateral
9x reserved

https://www.weather.gov/tg/awips
https://www.weather.gov/tg/headef
(sections 3.4.1 and 4.3.1) https://www.icao.int/EURNAT/EUR%20and%20NAT%20Documents/EUR%20Documents/EUR%20Documents/014%20-%20EUR%20SIGMET%20and%20AIRMET%20Guide/EUR%20Doc%2014%20%20(EN)%20-%20Edition%202,%202010%20-%20rev%2029Oct2019.pdf


Are commercial pilots incentivized to reduce fuel consumption?

There have been, at various times, and with various carriers, incentive programs set up to encourage pilots to save fuel, improve on-time performance, or some combination of the two.

An example of a fuel-saving incentives program existed at the former Continental Airlines in the early 90s, where pilots would be paid a bonus for using less fuel than planned. The problem was that it wreaked havoc with the schedule itself, as pilots would simply dial back to economy cruise thrust settings, saving fuel but taking noticeably longer to reach their destinations.

An example of an actual-vs-scheduled block incentive program intended to help with on-time performance existed at Silver Airways in their Beech 1900D fleet, whereby pilots would be paid a bonus for each minute they were able to shave off a baseline target time. Ironically enough, it was called the "Green Incentive Program" (don't ask). And it was a can of worms.

I vaguely remember other airlines experimenting with incentives programs relating to fuel consumption and on-time performance, but it's been several years since I left the industry and can't recall any other examples.

In short, yes they do get implemented fairly regularly, but they can be very problematic due to the difficulty in properly designing and managing them (incentivization is a complex problem).

Lastly, since another poster has brought this up, dispatchers do indeed perform most, if not all the flight planning, but the PIC (i.e. Captain of the flight) has the option of overriding most everything the dispatcher plans and arranges for (subject to the carrier's Operational Specifications), including amount of fuel to be carried. Basically, if the Captain decides that the plane is to be filled with as much fuel as it can carry up to MTOW, that's what's going to happen. Might not be the most business-savvy (or even prudent) decision, but it's part of their prerogative as PIC (i.e. the person ultimately responsible for the craft, crew, passengers, and goods onboard).


How is the correct air speed for fuel combustion obtained at the inlet of the combustor?

Combustors usually feature recirculation zones in which the combustion takes place either completely or which at least anchor the flame. This can be done by several designs

Sudden jump in cross-section in combination with vorticity
Flame-holder bodies
Central displacers
Vorticity brake-down

The blade channel of a compressor is actually divergent. Deceleration of a flow goes along with an increase of the static pressure (see diffusors). Additionally, a compressor transfers work into the fluid, thus further increasing the fluid density. The divergent cross-section of the annular channel between hub and casing is designed to keep the axial velocity somehow level. High axial (or more correctly meridional) velocity levels cause higher friction losses. Low velocities reduce the transferable power of a compressor stage, thus requiring more stages.


What are the dimensions of an NPT pipe for fuel systems?

Mechanical engineering uses a particular wording, I hope I'll not lose myself in the translation... Feel free to correct.

This fitting, standardized in ASME B1.20.1, has the particularity to have conical nut and screw:

The thread is tapered:

Larger diameter ($\small \rm E_2$) = 1.00178 in
Smaller diameter ($\small \rm E_0$) = 0.96768 in
Effective length $\small \rm L_2$ from $\small \rm E_0$ to $\small \rm E_2$ = 0.5457 in

1) How do I decipher the specified pipe size? This one is 3/4

Difference in diameter over $\small \rm L_2$ = 0.0341 in. As $\small \rm L_2$ = 0.5457 in, this is equivalent to 0.75 in per foot (12 in) or 3/4 in/ft.

This is where the size 3/4 comes from.

2) Why would the unthreaded side have the diameter 1.050 in? I want to connect it to a pipe with a 1.0 in

When fully engaged, the screw thread and the nut thread are fully adjusted. The extremity of the screw is at the reference plane (see figure), and the nominal diameter is $\small \rm E_0$

$\small \rm E_0$ is smaller than $\small \rm E_1$, the diameter at the extremity of the nut, both are smaller than $\small \rm D$, the external diameter of the screw.

For a threaded screw, the "diameter" is often the diameter of the unthreaded rod, this is also the case here $\small \rm D$ = 1.05 in.


What is the procedure for handing over controller positions to the next shift?

I've asked an ATCO friend of mine who is in Greece in area control center and he told me is that there are no regulations; only good practices. For example, since for each sector you don't have one but two controllers, you don't change planner and radar operator at the same time. You might switch them 15 or 20 minutes apart. The supervisor is not involved in the process (there are several positions changing at the same time, who should they attend first?) and besides they are already busy with bigger things.

The current controller will need to brief the next one only if there is something unusual. Otherwise, the controller knows what sector they will take over and the sector peculiarities. Glancing at the current traffic will give them a good picture of what is going on. The relieved controller can stay next to the one who relieved them as long as they want but again, there is no time specified by regulations. But usually one or two minutes is enough. Usually an informal "Joe can I go? Need me anything else?" is enough and in the vast majority of cases the response will be affirmative.

This is specific for the Hellenic ACC, I don't know what happens in approach or tower positions although I have a feeling that things are not extremely different.


What is the material and font used on the panels of most cockpits?

Materials: You'll find several materials used for visible 737 flight-deck panels and structure. Most of the panels themselves are aluminum plates, with fiberglass, kevlar, and other plastics rounding out the space.

Font:  Boeing uses something close to a flavor of Futura on its panels.


Is it possible to create a direct supersonic airflow to a turbofan's afterburner in order to enhance the performance or reduce the fuel consumption?

The J-58 took compressed air from the compressor at stage 4 and piped it directly into the flow aft of the turbine. This cooled the exhaust stream that entered the afterburner, so the starting temperature there was lower and the density higher, which increases efficiency and thrust. Note that the intake of the SR-71 slowed the flow down to Mach 0.4, so all internal flow was subsonic. Only when the hot exhaust gas in the afterburner expanded again would the flow speed increase to supersonic speeds again.

This is only possible because the intake would already compress the air by a factor of nearly 40 when flying at Mach 3.2. This precompression scales with $$p_0 = p_{\infty}\cdot\frac{(1.2\cdot Ma^2)^{3.5}}{\left(1+\frac{5}{6}\cdot(Ma^2-1)\right)^{2.5}}$$
so the precompression is much lower (less than 6) for a typical F-414 maximum speed of Mach 1.8.

($Ma$ = Mach number, $p_0$ = ram pressure, $p_{\infty}$ = atmospheric pressure).

The gains in efficiency scale with the ratio of starting and exhaust temperatures (measured from absolute zero), so the increase in efficiency is much lower than what you seem to hope for.

Make sure that flow speed at the entry of the afterburner is decidedly subsonic. Supersonic flow at the start of the afterburner section will only delay ignition until the flow exits through the nozzle. All afterburners have rings inside, called flameholders, which cause local separated flow, so some burning gas is always present to ignite the newly arriving fuel-air mixture.


Why does the CF6/CFM56 Turbofan Fan Frame contain 12 circular holes between the primary and secondary flow?

Short answer

These holes are vents used to discharge air from the primary (core/hot) flow into the secondary (bypass/cold) flow. They are normally closed by valves (variable bleed valves, VBV). The valves open to maintain the compressor pressure/flow within a safe area.

VBV in operation: Youtube

VBV on a CFM56-5 (also visible the VSV). Source

VBV are a mean to prevent a compressor stall in turbo-engines. A  stall appears in situation like this:

For some reason, e.g. when thrust is reduced, pressure at the compressor exit exceeds by a large amount its inlet pressure.
When the pressure ratio is beyond the compressor capability, air at the exit starts opposing compressor airflow, a reverse pressure wave is created, which propagates to the inlet.
Flow over one or more compressor blades is disturbed and the airfoil stall angle is reached creating an aerodynamic stall.
The stall is extended to the next blades, i.e. a rotating stall develops.
The pressure ratio is getting unstable.
Thrust is suddenly reduced, attempts to increase thrust accelerate the stall.

The VBV are used to adjust the compressor pressure ratio, by discharging some air between the LPC and the HPC. This decreases both the pressure ratio of the LPC and HPC and helps preventing compressor stalls.

Holes location

The fan frame assembly shown here without its outer shroud:

Fan frame assembly, without its outer shroud, of a CFM56-7B. Source

comprises two rings of 12 stationary vanes which are crossed by:

The primary (core/hot) flow for the inner vanes
The secondary (bypass/cold) flow for the outer vanes.

The 12 holes/vents in the mid-box structure of the fan frame assembly are closed by 12 variable bleed valves (VBV):

VBV in a CFM56-5A. Source

The valves are protected by a grille:

Source

Location of these elements in the engine:

Location of the fan frame in a CFM56-5. Source

Details:

VBV on a CFM56-5. Source: CFM56-5 Training Manual

The master valve is controlled directly by a motor, the other valves are linked to the master VSV by a flexible shaft.

5: Fuel gear motor powered by HMU, controls position of the master VBV
1: Master VBV
2: Position feedback
4: Position sensor
7: Flexible shaft controlling the other valves

VBV use

As regard to the cold flow, the inner duct is located between the low pressure compressor (aka booster) and the high pressure compressor. The pressure delivered by the compressor section is optimized for maximum engine power.

When the engine speed is low or the engine is decelerated, the LP compressor pressure can increase and clear the LP compressor stall margin. In such a case, the VBV are opened to release some air into the secondary flow and restore the margin. Conversely, when thrust is increased, the risk of stall disappears, the valve is closed to restore efficiency. The following diagram shows how the action on the valve contributes to keep the compressor flow in the designed working area.

Stall prevention using VBV. Source

More on VBV and stall prevention:

What is the difference between variable and transient bleed valves?
How does the FADEC prevent compressor stall during rapidly increasing thrust demand?

VBV for debris rejection

On military aircraft, unsuccessful attempts have been made to use VBV to capture and reject debris and water. The principle is to create a bend in the airflow with an opening at the start of the bent section. Heavier elements are captured by the hole. CFMI has reintroduced this technique in the LEAP engine.


What is the significance of a clover-shaped flight track?

The flying looks too sloppy for a ground reference maneuver, a performance maneuver, or other required academic flying.  Given the concentration of the same flying in that same area and a review of the VFR sectional for the same area:

This is probably some kind of training flight.  If it is for law enforcement, I'm not sure what is going on here.  One possibility is that it is a student practicing attitude instrument flying doing 'A' and 'B' patterns under the hood with an instructor - or at least trying to.

Another possibility is just standard flight training activities, periodically turning to avoid terrain or congested airspace in order to operate within these confines.


Why does the Antonov 225 needs 6 crew members?

A quick search points to the following being part of the crew

Pilot
Co-pilot
2x Flight engineers: one on the engine controls; I am not sure of the purpose of the second one but a good guess is hydraulic and electric system monitoring, based on his proximity to the circuit breaker panel (source, scroll down for a 3D photograph of the flight deck).
Navigator: due to the age of the type and the amount of non-standard routes it flies.
Radio operator: same reason as above.

The crew could likely be reduced after a modernization of the cockpit, without upgrading any other hardware like the engines, but the re-certification costs probably outweigh the benefits in this case, for a fleet size of 1.

Mostly sourced from this thread: discussion on Airliners.net about the An-225 crew duties, which also includes good images with annoyingly restrictive copyrights.


How do I fill the PBN\ part in a Flight Plan Form?

You have 8 items selected, and the max allowed is 8. There is guidance material from ICAO with steps to follow on how to get down to the 8 (in case you exceed it in the future). Right now you're fine.

For example:

  If having applied the guidance provided in Step 3 there are still more than 8 PBN codes remaining:

    Identify the capabilities considered to be the least relevant to the flight;
    Insert them under Item 18 within the NAV/ element;
    Insert the letter 'Z' in Item 10a.

  For example, the codes relating to long range Oceanic capabilities (A1, L1) will not be a priority if the flight will take place entirely within European continental airspace. Inclusion of an RNP APCH capability will not be a priority if none of the destination or alternate aerodromes provide such a procedure.


What is this trio of fins at the back of a T-38?

There are a couple of possibilities, both out of the T-38 Flight Operations Manual.

It's a nozzle for a smoke generator.  This was an option on the T-38 airplane to generate a smoke trail behind the aircraft for training purposes.

If possible, inquire if that aircraft was an AT-38B.  Those aircraft apparently had an optional 'ballast box' in that region, which I'm assuming was some sort of a counterweight placed there in conjunction with the bomb racks for practice bombs and other range equipment.

As to the vortex generators?  Who knows!


Why do the B747 of NASA Shuttle Carrier Aircrafts (SCAs) need additional vertical stabilizer?

The AN-225 was designed primarily for carrying the Buran, so they didn't have to make structural changes to an existing design to accomodate the carrying of the shuttle. The aircraft was purpose built for that mission (although it never really saw much of that in practice).

The NASA 747 on the other hand, is a stock 747 that they added the ability to carry the Space Shuttle on its back. They couldn't remove the vertical stabilizer on the 747. Due to the shielding effect of the airflow when the shuttle is attached, they needed additional yaw control that required them to add the outer stabilizers.

The 747's used by NASA were converted passenger aircraft. The first one, N905NA was acquired from American Airlines made in 1974, the second one N911NA was bought from Japan Airlines, built in 1973 and acquired by NASA in 1990 or 1991.


Which procedures or devices do ensure the aircraft stop flying after the pilot has ejected?

As you pointed out, the only reason for abandoning an aircraft is because the pilot can no longer control it or successfully land it.  With or without flight crew onboard, it's going down in one form or another.  As such it's pointless to design any additional system to disable or destroy the aircraft as it accomplishes nothing.

Pilots however have been known to direct a stricken or otherwise doomed aircraft away from populated areas, as this Thunderbirds pilot did at a 2003 air show at Mountain Home AFB, in Idaho.

So too was this crash of a MiG-29 at the Paris Airshow in 1989.  Mikoyan test pilot Victor Kobachev ingested a bird in his starboard engine and the jet departed controlled flight;  Kobachev fought to direct it away from the crowd line before he punched out.


Main structural (and any other) impact of hard landing

here are the main parts at risk for structural integrity after a hard landing:

the landing gear itself and the attachment points of the gear to the fuselage and/or wings

the fuselage-to-wing attachment structures

the engine-to-wing (pylon) or engine-to-fuselage attachment structures

the main fuselage structure in the immediate vicinity of the wing attachment points

If the hard landing involves a tail strike, then the integrity of the aft pressure bulkhead is at risk.

Note that the structural integrity risk is not simply one of prompt failure due to an overstress impulse load, but also subsequent premature fatigue failure arising from microcracks caused by the hard landing stresses- especially if that cracking occurs in a location which is inaccessible for inspection.


In the Lockheed Martin Flight Services system, what are MIFR, MVFR, YFR and ZFR flight rules?

According to the tooltips on the Lockheed Martin site, the flight rules are:

  MVFR - Military VFR; restricted to military flights
  MIFR - Military IFR; restricted to military flights
  YFR - Initially operated under IFR, followed by one or more changes of flight rules
  ZFR - Initially operated under VFR, followed by one or more changes of flight rules

There's very little information on MVFR and MIFR flight plans that I could find, but the FAA's FSS procedures do include specific actions that are required when receiving a military flight plan (section 6-4-7).

YFR and ZFR are ICAO rules; the FAA calls combined VFR/IFR flight plans composite flight plans (see section 5-1-7 in the AIM) and on a US domestic composite flight plan both VFR and IFR should be checked. Interestingly, the Lockheed Martin site doesn't allow that.


Why do most commercial airplanes use hydraulics instead of electric/servo motors?

I'm sure it's possible to use servo motors to get precise control of the ailerons, elevators or the rudder.

No, it isn't. Primary flight control actuators require both rather high forces and quick response time. Electric motors can provide either, but both at the same time is a problem. Hydraulics is still better for that combination.

Note that other actuators that don't require the fast response time (like flaps, gear or horizontal stabilizer foreplane (elevator trim)) are electric in some aircraft.