Can Part 141 instrument simulated time be logged?

The FAA's Advisory Circular 61-136B addresses this subject and explains how time on an advanced training device should be logged:

D.3 Logging Training Time and Experience.
Authorized instructors
utilizing an FAA-approved ATD for airmen training, pilot time, and
experience requirements are required to log the time as dual
instruction and as basic aviation training device (BATD) or advanced
aviation training device (AATD) time appropriately. Any columns that
reference flight time should remain blank when logging ATD time. ATD
time can only be logged as Instruction Received (Dual), Instrument
Time, or Total Time as reflected on the pilot time section of FAA Form
8710-1, Airman Certificate and/or Rating Application. Simulated
instrument time can be logged in an ATD, but only during the time when
the visual component of the training session is configured for
instrument meteorological conditions (IMC) and the pilot is
maintaining control solely by reference to the flight instruments.
Logging time in this fashion will allow a pilot to credit this time
towards the aeronautical experience and instrument experience
requirements as specified in part 61 or part 141. It is required under
§ 61.51(b)(1)(iv) that the type and identification of the ATD be
included when logging pilot time as described in the letter of
authorization (LOA). It is the responsibility of the flight
instructor, student, or certificated pilot to verify the device is
qualified and approved for training or experience requirements. It
would be appropriate for the person using the ATD to retain a copy of
the LOA. Evaluators such as Designated Pilot Examiners (DPE) are
instructed to request a copy of the LOA from applicants logging ATD
pilot time, to verify the time acquired in the trainer qualifies for
the minimum experience requirements for a certificate or rating.
Note: There are no restrictions on the amount of training accomplished and
logged in training devices. However, the regulatory limitations on
maximum credit allowed for the minimum pilot certification
requirements are specified by parts 61 and 141 and in the LOA. No
approvals or authorizations are provided for aircraft type ratings
using ATDs.


Does an engine that combines an air-breathing rocket and non-air-breathing rocket exist?

There's a very recent claim for an engine called Fenris, which claims to be a no-moving-parts "rocket" that uses ambient air for its oxidizer.

On the face, that sounds like a ramjet, but the claims made by the inventors appear (to me) to be investor bait, rather than anything that could actually be true.  Video on the entry page at the inventor's web site shows a burn more like that of a poorly designed torch, than a rocket or jet.

As noted in comments, there is also the SABRE engine concept -- this is not yet a working engine, as far as I know, but will/would be a hydrogen-fueled turbo-ramjet which uses the liquid hydrogen to liquefy intake air while in jet mod, for use as oxidizer when it switches to rocket mode.  The intent is for use as a spaceplane-to-orbit.


Mode-S provides altitude and identification data, with Automatic Dependent Surveillance Broadcast (ADS-B) adding global navigation data typically obtained from a Global Positioning System (GPS) receiver. The position and identification data supplied by Mode S/ADS-B broadcasts are available to pilots and air traffic controllers.


Can military officers change occupation to become pilots?

In the USAF, it has, historically, been common for rated Navigators to be selected for pilot training, and possible, though less common, for young officers in other career tracks as well.

That said, this process is

competitive (so certainly not guaranteed for a particular individual), and
dependent on the "needs of the service", so what is going on "now" may be entirely different from what was going on "then".

Also, the demand for UAV operators may have changed this dynamic considerably; it may be a far different process to become a "drone pilot" from a non-rated field, than to become a "real pilot."  Talking with active duty officers (not recruiters) who are up to date on this landscape is indispensable for getting the most current picture.


Where should I sit to experience the least turbulence?

The elasticity of the fuselage does indeed dampen the load factors from gusts somewhat. Therefore, gust-induced accelerations are a little higher over the wing than in the forward or rear fuselage. If the gust causes a pitching motion, this creates its own accelerations which adds to the bumps from the vertical accelerations. Elevator deflections cause similar pitching motions, and their accelerations are more pronounced in the rear fuselage since the aircraft will pivot around a point ahead of the center of gravity.

The main factor, however, is the location of the axis of rotation of the Dutch roll eigenmotion of airliners. This is a weakly damped oscillation which creates lateral accelerations which are bigger the more aft you sit in the fuselage. The Convair 880 was hurriedly test-flown with nobody sitting in the back, and the pilots were happy with its comfort level. The first passengers, however, got seasick from the Dutch roll motion, which was only detected when the passengers sitting in the rear of the cabin complained.

Modern airliners offer better comfort thanks to artificially enhanced stability, but even there you are better off sitting in front. I once flew on an Egypt Air Boeing 777 from Cairo to Frankfurt, and the captain flew through the tops of Cumulus clouds sitting over the Alps. Soon the obvious sounds and smell told me that people in the back were filling their air sickness bags. Maybe half of the rear third of the seats was affected, while the forward two thirds had only a few cases of airsick passengers.


Do FAA sectional charts show all power/transmission lines?

From the FAA's Chart Users' Guide:

  AeroNav Products’ charts are prepared in accordance with
  specifications of the Interagency Air Cartographic Committee (IACC)
  and are approved by representatives of the Federal Aviation
  Administration (FAA) and the Department of Defense  (DoD).

Book 2 of the IACC Specifications covers Sectionals and VFR Terminal Charts and provides the following guidance for transmission lines:

  3.6.6.3 Telecommunication and Power Transmission Lines (T-Lines)

  3.6.6.3.1 Landmark Value

  T-Lines, if depicted on charts, are shown primarily for their landmark
  value. Determination of whether a T-line has landmark value or what
  constitutes chart congestion are matters of FAA Flight Edit judgment.
  Flight Edit shall either delete or add T-Lines on the Flight Edit
  Standard. T-lines with landmark value should be shown in open country
  and not in congested or built-up areas. Through open country, T-lines
  should be shown as continuous lines, interrupted only for reasons of
  cartographic practices. Location of the pylon symbol is dependent
  upon the length of the T-line; approximately at 1" intervals on a line
  3" or less in length, and approximately 2" apart on lines longer than
  3".

The transmission lines may also be charted under the rules of section 3.9.8.6 Obstructions.

So, no. T-Lines are not charted exhaustively. They are charted only when they have landmark value or are charted as an obstruction.


Which type of control gives a more agile missile, tail or canard?

Since the control unit sits at the tip of the missile, it is simply more practical to control it via canard deflections. The rear part can then be made as a simple pressure vessel with fixed fins and a nozzle.

If the rear fins would have to move, their actuators would either be in the way of the nozzle flow or would stick out on the outside - in both cases performance would suffer. Also, long cable runs along the side of the missile would need to be added.

By controlling the missile with the forward fins, any change of direction will be direct, whereas control via the rear fins means that the rear end of the missile would initially move away from the desired direction, until the change in attitude would move the missile towards its target. Thus, the canard will result in a more agile missile.


What is the ATC phraseology to request a parallel track?

It is rather simple:

  OE-DLM, request 2NM right of track.

However, weather circumnavigation is mostly done with headings. This way it is easier for the controller to predict your movement and thus preferred by many:

  OE-DLM, request heading 120 for the next 20NM to avoid (weather).

This way it is easy for the controller to predict your movement and he has an idea where your avoidance will be completed. Additionally you are not forced to turn behind a cell you weren’t able to look behind before.

Mainly done in oceanic airspace where you try to make your way through the ITCZ (InnerTropical Convergence Zone) is this variant:

  OE-DLM, request up to 20NM right of track to avoid (weather).

If approved you got a 20NM wide corridor to play in.

Flying offset is rather uncommon in the crowded European airspace (or generally every crowded airspace) but a normal thing everywhere else. China even uses it as a tactical separation method employed by the controller.


Are there any safety data on the aircraft used for skydiving?

You didn't mention any particular country, but for the US I found an NTSB report called On the Safety of Parachute Jump Operations. It's from 2008 so some of it may be dated, but it says that no reliable data exist (emphasis mine):

  According to USPA safety records, from 1992 through 2007, about 30
  parachutists per year were killed in jumping mishaps. Safety Board
  accident data show that, for the same time frame, about five
  parachutist fatalities per year resulted from accidents involving
  parachute operations aircraft. Direct comparisons of associated risk
  are difficult to calculate due to the likelihood of multiple
  parachutists being carried on each flight and a lack of departure data
  for parachute jump operations. The Safety Board notes that the FAA
  does not have data on the number of parachute jump operators or the
  number and type of aircraft used in parachute jump operations in the
  U.S. The absence of these data precludes any calculations of safety
  statistics for parachute jump operations, including accidents rates.

Based on that information, you have 5 fatalities per year related to aircraft, and 25 that are not. So the aircraft should be the least of your worries.

Here are some key points from the rest of the report:

  a segment of U.S. general aviation operations, which, according to
  data compiled by the United States Parachute Association
  (USPA),[1]transports parachutists on 2.16 to 3 million jumps
  annually.[2]

  [...]

  Since 1980, 32 accidents involving parachute operations aircraft have
  killed 172 people; [6]most of whom were parachutists.

  [...]

  The investigation identified maintenance discrepancies on the airplane
  and deficiencies with the pilot's performance of emergency procedures;
  these issues prompted the Safety Board to examine accident reports for
  parachute operations to determine if such safety issues may be
  widespread. The results, discussed in this investigation report, show
  that these issues were present in many accidents

  [...]

  The Safety Board's review of parachute operations accidents since 1980
  identified the following recurring safety issues:

  Inadequate aircraft inspection and maintenance;
  Pilot performance deficiencies in basic airmanship tasks, such as preflight inspections, weight and balance calculations, and emergency
  and recovery procedures; and
  Inadequate FAA oversight and direct surveillance of parachute operations.

Anecdotally, skydiving is indeed associated with poor maintenance and hiring low-time commercial pilots. It's one of the few commercial activities that doesn't require an air operator certificate (see 14 CFR 119.1(e)(6)) so it can operate under part 91, without the more stringent rules and requirements of part 135. That also means there are no minimum hours required for the pilot as long as he holds a commercial certificate, and it's a very sought-after job for commercial pilots who want to build hours without instructing.

However, anecdotes tell you nothing useful at all about the overall safety of the industry, or about the safety of an individual skydiving operation. Some research is good and I think you can look for some common sense things that you might look for in any business: professional location, good customer service, good online presence, good reviews etc. But trying to quantify the risk in a meaningful way is extremely difficult, and you still have to balance it against the reward and against the risks of whatever else you would do that day instead of skydiving.


How does an aircraft derive winds aloft on its own?

Yes, you are correct. You need three pieces of information:

airspeed
true compass heading (considering magnetic variation)
multiple absolute position fixes (eg. from gps)

The aircraft heading has to be measured by a compass within the aircraft (it can't be derived from the gps track), and the gps position can be used to look up the local magnetic variation. The difference between the speed/heading and the ground track (in straight and level flight, anyway) is attributable to winds aloft.


Is baggage always offloaded when a passenger does not travel?

Normally, baggage takes much longer to switch flights than self-loading cargo, so your scenario is highly unlikely.

In the event of a passenger missing and his/her baggage already on board, all bags need to be unloaded until the orphaned bag is found. When ULDs are used, those must be unloaded first and are then unpacked, mostly on the apron next to the aircraft.

Waiting for the missing passenger is an open-ended game. At some point, you must decide on a course of action with a fixed exit so you can move on.

Normally, every airline is required to unload an orphaned bag. I am sure some are more strict about this than others.


Would connecting propeller blades with a continuous ring reduce induced drag?

What you're talking about does exist, they are called Q-Tip Propellers.

Remember that a propeller blade is just an airfoil - like a wing - and the basic aerodynamics are no different than a wing. But the rotation of the blade creates more phenomena than a wing, in particular the helicoidal vortex one sees behind the prop and causes all sorts of propeller effects.

In theory, nothing would prevent us from having winglets at the prop tips :
the advantages would be

Making the prop more efficient by reducing the induced drag (same as a winglet on a wing )
Reducing noise
Keeping the propeller tip speed subsonic by decreasing its length

The big problem is in aerodynamic stresses, and as far as I know there have been some quite spectacular failures during testing, so the solution is now to give a greater sweep to the tips (see that as equivalent to the 777 wing tip compared to the 787 for instance). Try and find articles on the Hartzell Q-tip.

As naval propellers are wider and capable of deealing with bigger torque stresses, modern ones do have winglets. You could find some pictures on the web.


How can I identify the aircraft’s phase of flight in this picture?

It is much lower than cruise altitude, I would guess roughly 4000-6000 feet.  The flaps are up because it is neither taking off nor landing.  Generally flaps are deployed around 2000 feet or below.  Given the proximity to New York City it is probably flying an arrival or departure procedure.

If you really wanted to dig deeper you could determine relative position and from Manhattan in the background and compare against published procedures into and out of the city's airports.


Is it allowed and possible to hold at the intersection of two VOR radials using a single VOR receiver?

As I understand it you are asking two questions:

is it permitted to hold at an intersection of two VOR radials with nothing more than a single VOR receiver? and
what are some tips and tricks for doing it?

Answer to question one:
As others have mentioned, it was permitted at one time (and I believe it is still permitted). I'm old enough to have received training on how to do it at a time where it was much more common to fly in GA aircraft with no DME or GPS and sometimes only a single VOR receiver. I spent over an hour researching this question for you in the AIM, Airplane Flying Handbook, Instrument Flying Handbook, and Instrument Procedures Handbook, and online generally, and was not able to find anything saying it was permitted or prohibited. I don't see any problem with it other than it adds a bit of workload to the pilot, but it can be done safely and relatively easily. If I find an definitive answer I'll update my question.
Answer to question two:
Here are some tips and tricks for flying an intersection hold with nothing but a single VOR receiver. This explanation assumes you know how to hold, including the FAA recommended hold entries.
There are two radials, hence the intersection. I'm going to refer to them here as the main radial and the cross radial. (It is possible to approach the fix on the cross radial then switch to the main radial for the hold after executing the hold entry, however, for purposes of this explanation, I'm going to assume that you are approaching the fix on the main radial (i.e. the radial on which the inbound holding course is located).
In the figure below the aircraft is on the main radial and is approaching the cross radial from the West. However, this aircraft could also be approaching from the opposite side of the fix from the East.

So, while you are on the main radial flying towards the fix, you want to spend most of your time monitoring the main radial because it is your primary course navigation, however, you also want to initially tune the cross radial well before reaching it in order to verify, and take a mental note of which side the CDI is deflected. This can be confusing to some pilots because the CDI will be either on the right or the left depending on where the station of the cross radial is located in relation the main radial. (When you fly a G1000 or HSI, the CDI rotates such that it is easy to tell when you are approaching the cross radial or have already passed it, but this is not the case in stand-alone old-school VORs). Whether the CDI of the cross radial is on the left or right also depends on if the pilot tuned in the radial or the reciprocal. For simplicity in this example, lets assume you tune in the cross radial well before reaching the intersection and the CDI is fully deflected to the left.
You then re-tune the main radial (hopefully your NAV radio has a flip-flop button), and center the CDI. You want to be as precise as possible and note the wind correction angle required and bug that heading! It's important to be precise, because you will be flying the bugged heading when you switch to the cross radial.
As you fly towards the holding fix on the main radial you will periodically switch back and forth to the cross radial until you detect the CDI is alive. At this point, you want to watch the CDI to get an idea of how fast it's moving.  I like to take a note of the deflection of the CDI, lets say it is 8 degrees to the left (still haven't reached it), then take a note of the clock to determine how long it takes to fly 1 degree. Let's say that it takes 30 seconds to go from 8 degrees to 7 degrees, if so, then you know you have approximately 3.5 minutes before reaching the holding fix (7 degrees x 30 sec/deg = 210 sec or 3.5 min). You can then switch back to the main radial and continue navigating on it, until about 1 minute before you reach the intersection, at which point you would tune in the cross radial and fly your bugged heading until the cross radial is centered. At which point you would peform the appropriate hold entry.
At the moment you reach the holding fix, you will be flying the bugged heading and the cross radial will be tuned into your VOR. If you are on the main radial on the inbound heading, then it will be a direct entry and you just turn (right turn in the above figure) and fly outbound. On the outbound leg, tune the VOR to the main radial to the inbound course so that you can intercept it when you turn inbound. If you are approaching the holding fix from the opposite direction (from the East in the above figure) such that you are flying the outbound heading of the hold, then you will need to do a teardrop or parallel entry. In this case, I like to do the parallel entry because it requires less math and turning. Since you are already flying the outbound heading and are parallel to the inbound course you don't have to do anything when you reach the holding fix from this direction other than start the timer or take a note of the time and fly out for 1 minute. During this one minute of flying outbound on the parallel entry, you will tune in the main radial to the inbound course, so that when you make your greater than 180 degree turn you can intercept the inbound course.
Whether you do the direct entry or parallel entry, once you are established on the inbound course and tuned into the main radial, you will need to bug in that heading, and promptly tune the VOR to the cross radial, because you've only got a minute or so on the inbound leg to intercept the inbound course, determine the WCA, bug it, then tune the cross radial to identify reaching the holding fix.
Then repeat until you're ready to leave the hold.
This was a long explanation, but it's really not as bad as it sounds. When you are practicing this on the sim, you can try flying 2 minute legs, which gives you more time to intercept inbound, then tune the cross radial. As you get more efficient, you can shorten the legs until you get to 1 min. BTW, in actual IFR, you can ask ATC for a non-standard leg length. I imagine any airplane in this day an age with no DME or GPS that only has a single VOR is probably a very very slow airplane, and ATC can probably accomodate 2 or 3+ minute legs, just ask.


This was one of the primary problems that needed to be solved in helicopter flight.

In my example, I'll use a 2 bladed helicopter, but this holds true with all helicopters, and I'll explain some of the different rotor types later on. The blade that is moving forward, relative to the direction of the helicopter, is called the advancing blade. The opposite is called the retreating blade, and you are correct in assuming that they would generate different amounts of lift. As a previous commenter noted, the term used for this is "dissymmetry of lift", and is the same thing that limits the maximum speed of a helicopter.

A two bladed helicopter will generally have what is called a "semi-rigid" rotor system. Semi rigid systems are only possible on even bladed helicopters, and are generally only used on 2 bladed helicopters. The two blades are connected together by a hinge on the rotor hub (where the blade meets the helicopter), and if you push down one blade, the other blade moves upward, and vise versa. What happens as you move forward is that the advancing blade (the one generating more lift) will get pulled up with a greater force than the retreating blade (the one generating less lift). As the advancing blade rises up (because of its additional lift), it pushes the retreating blade down. This advancing blade, in pushing up the rotor, is reducing the angle of attack of the blade against the airflow, which in turn is going to reduce its lift. The retreating blade is hinging downwards, which is increasing its angle of attack against the airflow, which will increase the lift it provides. These two forces will work against each other until they are in balance, which means that the advancing blade and the retreating blade will even out in the lift they are generating, which removes the dissymmetry of lift.

The blades in a helicopter are spinning at a some speed, which varies depending on where on the blade you are talking about (the tip or near the rotor hub, for example), but to simplify this explanation, I'm going to assume that the blade is traveling at the same speed along its entire length. Let's say that the blade is spinning around at 100mph at its tip. As the helicopter moves forward, at let's say 50mph, then we have one blade that is moving against the air at 150mph (the advancing blade), and one that is moving against the air at 50mph (the retreating blade). As the helicopter gets closer to 100mph (the speed of the blades), at some point, the speed of the air against the retreating blade will get closer and closer to 0. When it hits 0, it will stop generating lift, and the helicopter will start to roll (now the rotor is only generating lift on one side). This effect, called retreating blade stall, is one of the reasons why helicopters are limited in their top speed.

Just as a side note, I have greatly simplified some of these explanations, so I am well aware that I have glossed over various parts of this explanation to simplify it.


Should I keep specific distance from Class B?

You should remain at least 500 feet vertical separation from the Class B airspace, considering your direction of flight in accordance with FAR 91.159 (proper VFR cruising altitude) if you are more than 3000 feet AGL.  Or 2-3 miles lateral separation from Class B airspace (no regulation, just common sense).

If the Class B floor base altitude of 5000 feet msl is at or less than 3000 feet AGL, you could legally fly up to just below the base of the Class B and therefore come dangerously close to other aircraft operating at 5000 feet msl within the Class B.  This is too close for safety (considering allowable altimeter error, you could actually be at the same true altitude as an aircraft flying in the Class B).

Bottom line, in my opinion, you should always be at least 500 feet vertically or 2-3 miles laterally from Class B airspace.

This is what the Aeronautical Information Manual states regarding Class B:

(see the AIM):AIM 3-2-2


Does the FAA require a specific grade of supplemental oxygen for part 91 operations?

Regulations don't usually include detailed technical requirements or specifications, but AC61-107B - Aircraft Operations at Altitudes Above 25,000 Feet Mean Sea Level or Mach Numbers Greater Than .75 / with Change 1 says (p. 33, emphasis in the original):

Only oxygen that meets or exceeds the Society of Automotive Engineers
(SAE) International Aerospace Standard AS8010 (as revised), Aviator’s
Breathing Oxygen Purity Standard, should be used.


Are pressurized passenger aircraft usually completely airtight?

No, the are not even nearly airtight, and leak air quickly on their own.
Air pressure is maintained with bleed air or a powered pump. FAA has a thorough, well-illustrated guide to the systems involved.

As for why they're not built completely airtight, aircraft are mostly riveted and glued, not welded, so their structure is inherently not solid. You'd need to use sealants throughout the structure, install and maintain seals on every opening, and compartmentalize a few systems that need outside air by design.

That's extra weight and maintenance, which doesn't have to be there, as cargo doesn't need pressure and humans need fresh airflow. The minimum rate is ~1.6 L/s/pax for survival and ~8 L/s/pax for comfort. More flow means more O2, giving more consciousness time if decompression happens (breathing low ppO2 greatly accelerates the onset of hypoxia), less CO2 (affecting cognitive ability and comfort), and less humidity, so that less odor is perceived and less water accumulates in the insulation.

With outflow valves closed, airliners normally lose about 400 feet (~5%) of their pressure difference per minute when new, this varies per airframe. The permitted limit is typically 750 FPM. High-flying aircraft like A380, A350, 787 are built with considerably lower leak rates, a safety margin that allows them to get certified above FL400 by providing more time to get to 10k ft in emergency.

As aircraft age, their leak rate can double and more, usually being close to the limit for an average airliner. A common offender is window frames rattling themselves a bit of clearance. When tested and found to exceed the limits, maintenance is required to bring the leak rate down. So even the current level of airtightness takes effort to maintain.


Is part 141 ground school really supposed to be 35hours?

A Ground School Syllabus needs to be checked and approved by the FAA.  As part of that approval, they will decide if it meets minimum requirements, and is expected to take the required hours.

If the actual delivery of the material in ground school takes a bit less (or more) time than approved, that is OK, so long as the approved syllabus is closely followed.

Source: https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_141-1B.pdf


Are fully electric helicopters suitable for military operations?

Battery weight is a huge negative. Liquid hydrocarbon fuels have energy densities of about 45MJ/Kg, and the significant advantage that as you use them, their weight stops needing to be transported.

A lithium-air battery is theoretically capable of getting close to the energy density of hydrocarbon fuels, but the best that's been achieved so far in the lab is about 6MJ/Kg. The energy density of lithium-ion batteries, which are the best that's deployable at present. are more like 1MJ/kg, at the cell level, or rather worse at the pack level. If you want to drop used batteries, your operating costs go way up.

An electric helicopter could be built, but its flight duration would be very short. Just like quadcopter drones.


How to determine Center of Gravity of the airplane parts?

Let’s start with a definition from Airplane Flying Handbook:

  Center of gravity (CG).

  The point at which an airplane would balance if it were possible to
  suspend it at that point. It is the mass center of the airplane, or
  the theoretical point at which the entire weight of the airplane is
  assumed to be concentrated. It may be expressed in inches from the
  reference datum, or in percent of mean aerodynamic chord (MAC). The
  location depends on the distribution of weight in the airplane.

Your center of gravity calculations will start out by deciding where you want to place the datum. Typically it is placed at the firewall, but sometimes it is at the tip of the spinner.

For every piece on the airplane you measure the distance from the datum. That is called the arm. For my Cherokee the front seats are at 37 inches from the firewall. Let’s say that the seats weigh 20 lbs. The moment is 20*37=740. There are two of them, so total moment is 1480. Do this for every item on the airplane and then add them up.

Divide the total moment by the total weight to get the center of gravity.

Lots of things are fairly easy to estimate: engine, prop, battery, seats, cowl, tail have easy to calculate centers of mass.

Where it gets complicated in your case is that some of the parts of the airplane can’t be treated as residing at a point. You would need to balance them to find their individual center of gravity. Or you could break them down into parts and add up the parts. For example, you could calculate the weight the last two feet of the fuselage and use the middle of that as its ARM. Then the next two feet, etc. Same with the wings.

If you are using standard parts there may already be CG information from other builders or the supplier.

This will give you an idea as to where the CG is but when you are done you need to weight the airplane and calculate the true CG. This article goes into detail on the method and calculations.


Why are "counterweights" used in aircraft production?

In the context of aircraft design and maintenance, the terms counterweight and ballast generally have separate and different meanings.

Both concepts involve mass used to balance, dampen, or adjust forces about a rotational axis. While ballast could also be described as a type of counterweight, it is best understood as working within the frame of reference of the entire aircraft since it adjusts the aircraft Center of Gravity (CG). Conversely, counterweights can be understood to work within a frame of reference that is smaller than the aircraft as a whole, such as an engine or a control surface.

I will address each separately.

Counterweights

Counterweights primarily serve three functions in aircraft design: balancing control surfaces, controlling propeller pitch, and balancing crankshafts in piston engines.

Control Surfaces

Counterweights are used to balance control surfaces about the axis of the hinge to avoid potentially dangerous control flutter. This balance is very important. Pilots typically check for counterweight structural security in preflight where able. Mechanics must recheck control surface balance after painting, and painting control surfaces is excluded from the list of preventative maintenance items that an aircraft operator can perform without a mechanics license.

From the A&P Mechanics Airframe Handbook AC65-15A:

  It is this out-of-balance condition that can cause
  a damaging flutter or buffeting of an aircraft and
  therefore must be eliminated. This is best accomplished
  by adding weights either inside or on the
  leading edge of the tabs, ailerons, or in the proper
  location on the balance panels.

The following excerpt from the Cessna 172M IPC shows the elevator counterweights, 23, highlighted in blue:

Propellers

Counterweights are used in some constant speed propeller designs to increase the pitch of the propeller blades. Engine oil pressure is used to overcome the force of the counterweights to move the propeller blades back to fine pitch. In feathering designs, the counterweights assist in moving the blades to the feathered position.

From the A&P Mechanics Powerplant Handbook AC65-12A:

  Propellers, having counterweights attached to the blade clamps,
  utilize centrifugal force derived from the counterweights to increase
  the itch of the blades. The centrifugal force, due to rotation of the
  propeller tends to move the counterweights into the plane of rotation,
  thereby increasing the pitch of the blades.

  Feathering is accomplished by releasing the governor oil
  pressure, allowing the counterweights and feathering spring to feather
  the blades. This is done by pulling the governor pitch control back to
  the limit of its travel. which opens up a port in the governor
  allowing the oil from the propeller to drain back into the engine. The
  time necessary to feather depends upon the size of the oil passage
  from the propeller to the engine, and the force exerted by the spring
  and counterweights.

AC65-12A Fig 7-11:

Crankshafts

Counterweights are used in piston engines for both static and dynamic balancing.

From the A&P Mechanics Powerplant Handbook AC65-12A:

  Crankshaft Balance
  Excessive vibration in an engine not only results
  in fatigue failure of the metal structures, but also
  causes the moving parts to wear rapidly. In some
  instances, excessive vibration is caused by a crankshaft
  which is not balanced. Crankshafts are balanced
  for static balance and dynamic balance.
  A crankshaft is statically balanced when the
  weight of the entire assembly of crankpins, crank
  cheeks, and counterweights is balanced around the
  axis of rotation. When testing the crankshaft for
  static balance, it is placed on two knife edges. If
  the shaft tends to turn toward any one position during
  the test, it is out of static balance.
  A crankshaft is dynamically balanced when all
  the forces created by crankshaft rotation and power
  impulses are balanced within themselves so that little
  or no vibration is produced when the engine is operating.
  To reduce vibration to a minimum during
  engine operation, dynamic dampers are incorporated
  on the crankshaft. A dynamic damper is merely a
  pendulum which is so fastened to the crankshaft that
  it is free to move in a small arc. It is incorporated
  in the counterweight assembly. Some crankshafts
  incorporate two or more of these assemblies, each
  being attached to a different crank cheek. The
  distance the pendulum moves and its vibrating frequency
  correspond to the frequency of the power
  irnpulses pf the engine. When the vibration frequency
  of the crankshaft occurs, the pendulum oscillates
  out of time with the crankshaft vibration, thus
  reducing vibration to a minimum.

  Dynamic Dampers
  The construction of the dynamic damper used in
  one engine consists of a movable slotted-steel counterweight
  attached to the crank cheek. Two spoolshaped
  steel pins extend into the slot and pass
  through oversized holes in the counterweight and
  crank cheek. The difference in the diameter between
  the pins and the holes provides a pendulum
  effect.

From the Continental O-300 overhaul manual:

  C-145 and 0-300 crankshafts have a blade extending from each side of the cheek between No's 1 and 2 crankpins for attachment of dynamic damper counterweights. Each blade has two holes bored through and steel bushed. Slotted counterweights fit over the blades and have holes bored through and bushed to match those of the shaft. Bushings are sized to produce the desired frequency.

The following shows those counterweights on an O-300 crankshaft that is apart for overhaul:

Source: own work

Ballast

Ballast provides a temporary or permanent change to overall aircraft center of gravity. Ballast might be included as a permanent part of an initial or modified design. When I was in flight training we used old aircraft tires filled with concrete as ballast to place the W&B of a U206G near a max gross weight and aft CG configuration for portions of mountain flying training.
I know glider pilots use ballast for adjusting aircraft CG as well.

From the A&P Mechanics General Handbook AC65-9A (this AC is cancelled, but this comes from my old print edition and is still accurate):

  Ballast is used in an aircraft to attain the desired c.g. balance. It is usually located as far aft or as far forward as possible to bring the c.g. within the limits using a minimum amount of weight. Ballast that is installed to compensate for the removal or installation of equipment items and that is to remain in the aircraft for long periods is called permanent ballast. It is generally lead bars or plates bolted to the aircraft structure.

  Temporary ballast, or removable ballast, is used to meet certain loading conditions that may vary from time to time. It generally takes the form of lead shot bags, sand bags, or other weight items that are not permanently installed.


Can passenger airliners hover completely motionless in the air?

In theory they can stop moving relative to someone standing on the ground. In practice this does not occur.

Aircraft fly through the air and, yes, below a certain airspeed, an aircraft will stall. Let's take a super-simple example to explain the situation:

You are standing on the ground on a very breezy day. It's quite windy on the ground, and blowing even harder at altitude. For the sake of this example, let's say at 15,000 ft. There is a 150Kts wind from the west. A small airliner is slated to go west at 15,000 ft and levels off but slows down to a cruise speed of 150Kts. The airplane is still moving through the air at 150 Kts, but the air is moving in the opposite direction at the same speed. In terms of a fixed point on the ground the airplane does not move.

However, big jets are capable of flying faster than even the biggest practical headwinds. You can, however, observe this in small aircraft on a gusty day (I have flown a PA-28 backwards in this scenario). Here is a video of someone doing it in a slow plane.

What is likely occurring is that a plane that is very high up and very far away appears not to be moving due to its small size in the sky and lack of surrounding points of reference.


Why did the FAA ban all supersonic flights over the United States, rather than only supersonic flight in densely-populated areas?

The short answer is a bad PR fallout following the Oklahoma City sonic boom tests, even though the tests were generally positive.

[The National Opinion Research Center] reported that 73% of subjects in the study said that they could live indefinitely with eight sonic booms per day.
(...)
The FAA's poor handling of claims and its payout of only $123,000 led to a class action lawsuit against the U.S. government. On March 8, 1969, the government lost its appeal. The negative publicity associated with the tests partially influenced the 1971 cancellation of the Boeing 2707 project and led to the United States' complete withdrawal from SST design.

The tested 96 Pa (2 psf) overpressure -- what an SST produces and is far lower than military jets -- according to concordesst.com is:

(...) equivalent to the pressure one would feel when putting a hand out of the window of a car travelling at 30mph.

A 1973 article by The New York Times, "Supersonic Civilian Flights Over U.S. Are Outlawed", does not give reasons, only that it was expected.

In a new order, the Federal Aviation Administration virtually outlawed today supersonic, flight over the United States by civilian aircraft, effective April 27.
The rule had been expected for three years, since the F.A.A. first proposed it in April, 1970, in a notice inviting comment for or against the action.
Accordingly, it came as no surprise to manufacturers of supersonic transport planes such as the British‐French Concorde and the Soviet TU‐144.
(...)
Congress canceled the Boeing‐General Electric program for an American SST twe years ago, for budgetary reasons.

The New York Times also reported in 1970 about the supersonic trials over populated areas in "West Scotland, Wales and England" with no reports of any damage.
Open questions
Was it politically motivated? Were there really no solutions such as the proposed corridors? Those and @CptReynolds' commentary that [the US] banned it to "prevent a European aircraft from capturing 100% [of the SST] market share with US airlines" are worthy of posts on Skeptics or Politics.SE. Over there they'd know where to dig deeper.
One of the things I found for example was a ban on Concorde before it set a tire in New York. So it was a ban that came before any evaluation for its subsonic noise. The Supreme Court eventually intervened and lifted the ban (The New York Times, 1977).
Another find was a quotation from Ohio Senator Clarence J Brown, saying:

I see no reason to oppose the SST [meaning Concorde] just because we were stupid enough to get out of the SST business ourselves (concordesst.com).


What's the north boundary of the KINS Class D? (Or: does a SUA designation take precedence over controlled airspace?)

According to the sectional chart, Class D airspace does not extend into the restricted area.

SkyVector KINS Sectional Chart

The restricted airspace starts at the surface to an unlimited altitude.  According the JO 7400_11A.pdf, Class D does not enter the restricted area.

Class E airspace is the same.


Why do some A380 main wheels have no brakes?

Because they are not needed (for the passenger variant). Addition of brakes increases the weight and complexity of the system, which is undesirable. Why add something that is not required?. If it is required, additional brakes can always be added, like in the (proposed) freighter version. According to flightglobal.com:

  Sixteen of the A380-800's 20 main wheels are braked, with the two aft wheels on each body landing gear of the passenger version not having brakes (unlike the freighter variant, where all 20 main wheels are braked due to its increased weights).

Also, Aft Axle of BLG is steerable to ensure better maneuverability for small radius turn (Body Wheel Steering); braking a steerable axle would require special linkages, increasing weight and complexity. This is not insurmountable, however- Boeing 777's landing gear is similar, but has brakes on all its wheels.


If the radio fails, can a pilot contact the tower by cell phone?

As I pointed out in another answer of mine, it is not legal to use a cell phone in flight, and as another answer to the same question says, it really doesn't work very well anyway..
Now, if the pilot has an emergency, they can exercise the emergency authority of the PIC as allowed in 14 CFR 91.3(b) to go ahead and use the cell phone.  If it is just the radio failure though, that isn't usually an emergency since there are other procedures in place for radio failures.
Radio Failure Procedures
AIM 6-4-1 contains the procedures to use in the event of a radio failure.
Basically, if the pilot is in visual conditions (VMC) and can remain that way, they should fly VFR (visually) and land as soon as practical.  If they can't remain in VMC then there are a number of rules which spell out the route and altitude that they should fly, as well as when they should start an instrument approach.
Once they get to an airport they will still need to get clearance to land if it is a towered airport.
AIM 4-3-13 covers that, and basically the tower will communicate with the pilot via light gun signals:


In the UK, which ATS unit would be responsible for CTR entry clearances?

The answer depends on which aerodrome you are talking about, and can be found in the UK AIP: http://www.nats-uk.ead-it.com/public/index.php%3Foption=com_content&task=blogcategory&id=165&Itemid=3.html

Click eAIP to open the electronic AIP. In the left menu, open the AD 2 Aerodromes section and navigate to the aerodrome in question. Then open the AD 2.17 section of that aerodrome.

In AD 2.17, airspaces related to the specific aerodrome are listed. Column 1 contains the airspace designator and lateral limits. Column 4 contains the responsible ATS unit.

As an example - the Birmingham (EGBB) CTR is controlled by Birmingham Approach.


How could a failed left wing cause a roll to the right?

The following is how I would interpret the information given in the report - this is to some extent speculation, also because the FDR plots in the report don't seem to cover that part of the incident. I'm very intersted in how other people interpret the data.

The report states:

  The airframe remained intact (minus the leading edge), and the load
  factor fluctuated around -2 g, for approximately 6 l/2 seconds. [...] airplane heading moved 20 degrees nose left, and a 15 degree right roll attitude was reached at the end of this period.

The fact that the left leading edge of the stabilizer was lost and that the heading is moving left makes me believe that the aircraft was in some kind of a slip with the right wing further forward in the wind. The negative load factor of -2 g indicates a lot of negative load on both wings - apparently more than the structure tolerated. Both wings "stalled negatively"1 at this point. Now if one wing goes missing (aerodynamically, even if not physically), it can't provide the downforce any more and the total momentum will cause the side of the aircraft where there is still a functioning wing to rotate down.

Because the right wing was probably pointing slightly forward (even more so if the left wing produced a lot of drag while or after failing, which seems likely), a roll to the right would make the aircraft more or less tumble over its own wing, with the wing upper surface pointing increasingly towards the airflow around a 90° right roll position. The resulting drag explains a very fast roll to a ~180° position. Starting from "10 to 15 degrees right wing down"2, that's about 160°.

Short version: Because the wings had negative load and were primarily drag surfaces at this point, everything is reversed. The side of the aircraft with less drag rolled towards the incoming airflow. In a negative angle of attack attitude, that's up in the aircraft coordinate system, causing a roll to the right.

1 3.1: Findings; 7. p. 48 (56 in pdf)
2 p. 20 (28 in pdf)


How does stall depend on angle of attack but not speed?

I believe you are confusing the wing angle of attack with the pitch of the aircraft.  Aircraft moving at a slow, near-stall speed, despite pointing the nose up, will still be traveling more or less horizontally.  Their VSI instrument will read near zero.  Whereas, if you take an aircraft moving quickly and pull the nose up to the same angle, the aircraft will, obviously, climb rapidly.

Why does this matter?  The angle of attack is defined based on the wing's motion through the relative wind.  The wing's orientation relative to the ground isn't involved in the definition in any way.  When the aircraft as a whole is climbing, the relative wind is coming down from above.  As a result the angle of attack is reduced, compared to what it would be if the plane were not climbing.

Just to show some quick numbers, suppose you took an aircraft moving at 100 kts in still air and pulled the nose up so that you are now climbing at 3,000 FPM (most aircraft will lose speed doing this, but the math is valid until the airplane slows down).  $1knot\approx100FPM$, so you'll now have an upward vector of 30 knots.  Your 100 kt airspeed is now moving up at an angle.  A little trigonometry:

$$\sin(x)=\frac{30}{100}$$
$$x=17.46°$$

So, your angle of attack is 17.46 degrees farther away from stalling when climbing at 3000FPM than it would be if your aircraft had the same pitch but was in level flight.

However, few aircraft have the engine power to sustain a climb at this rate.  The aircraft will bleed off speed, and as the speed bleeds off, the aircraft will slow, the climb rate will decrease, the aircraft's velocity will become closer to horizontal, and, eventually, the aircraft will stall if the pitch is held constant.


If AWOS reports IFR conditions but I can see at least three miles, can I take off or land?

In the specific case that you mentioned (VFR at an uncontrolled field), you can take off or land because the only legal requirement is to maintain VFR cloud clearance and it's your responsibility at the pilot to do that. The possible downside would be that if you have some kind of accident or incident and the FAA or NTSB investigates, they will take the AWOS reports as the reference for weather conditions at the time. If weather or visibility was relevant to the accident then your decision might be questioned, unless of course there are witnesses who can confirm the actual conditions.

In the case of a controlled field and VFR, ATC will base their actions on the reported conditions so they would tell you that the field is IFR only. One 'workaround' that could be useful is an SVFR clearance, which allows you to operate VFR in an airport surface area even below VFR minimums. You have to request it because ATC can't offer it although they may hint strongly at it to help you out: "the field is IFR, is there anything you'd like to request?" But ATC may not issue an SVFR clearance if the reported visibility is below 1 mile, so in the scenario you mentioned it wouldn't help you. (And note that you need an instrument rating for SVFR at night.)

Under IFR the picture is different. A part 91 IFR flight can legally depart in zero visibility so there would be no issue there, provided that you get your clearance on the ground first, before entering IMC. Legal in this case obviously isn't the same thing as safe, though.

I deliberately didn't answer your second question because I think it would be best for you to submit it as a separate question.


Why are modern commercial airplanes still so noisy?

Like everything in aviation its a trade off of a few factors.

Efficiency: A non-running engine is pretty quiet but that's of little use to a pilot who needs thrust to actually go anywhere. Now you can have lots of sound suppression in an engine and alter the airflow and what not but in the end of the day jets work on Newton's third law so you still need to throw a hot mass out the back. Any attempt to baffle this will take a toll on efficiency. (Side note, car exhausts have a similar effect on car engines these days).

Weight: The generally accepted way to reduce noise is to insulate against it. What you are really doing is adding material to absorb the mechanical energy that is the sound wave and dissipate it. Generally this is done with insulation of some kind (there is a variety of styles). But like anything this takes a toll on weight and will reduce what you can carry.

Cost: Insulation does wear out and break down over time (its usually some kind of foam), so the more you have the more you need to replace. Also of importance is the fact that most of it gets removed during check to inspect the airframe so having a lot of insulation will add to your down time during checks (this costs the airline money in terms of hours).

If you take a look at some custom-built private planes you will see some of the things they can do in terms of added noise reduction and what those implementations look like. On the other hand active noise control is becoming a cheaper and more efficient technology in headphones which makes a case for not needing to improve insulation (it will eventually be cheaper to have a pair of ANR headphones for everyone than maintain a lot of insulation). A lot of the GA community has moved to ANR headsets which are much nicer than their traditional counterparts.


In Raymer diagram "Take off parameter- Take off distance", what is the difference among "balanced field length", "over 50 ft", "ground roll"?

Let's clarify:

Large commercial airplanes take off in a way which ensures there is sufficient runway length to stop in case of aborted takeoff. There is a speed threshold, V1 speed or decision speed, that determines whether the takeoff can still be aborted, or the airplane must continue and liftoff whatever happens. See balanced field takeoff on Wikipedia.

The balanced field length is the minimum runway length to execute a balanced field takeoff for a given aircraft. The V1 speed in this case is the lowest possible. Additional runway length allows greater V1 to be selected (greater V1 means a greater portion of the ground roll with a possibility to abort the takeoff).

V1 value and balanced field length (source)

50 ft distance: This is the distance from the start of the ground roll to the point where the aircraft is airborne and 50 ft over the runway, to ensure obstacle clearance. 35 ft is another typical obstacle clearance in the US, and indeed the distance to climb to 35 ft is shorter than the previous one (a 35 ft clearance is implicitly used to compute the balanced field distance)

Takeoff roll distance and Obstacle clearance distance (source)

Using the diagram

From this slideshow which reproduces the figure you refer to:

(Source)

This depicts the relationship between takeoff parameter and different distances, either the ground roll distance or the obstacle clearance distance (35 and 50 ft) in the three types of takeoff described above.

There are three groups from left to right:

Jet using balanced field T/O (the obstacle clearance is implicitly 35 ft).
Jet not using balanced field T/O.
Propeller (not using balanced field T/O).

In these groups, there are one or two data provided:

Jet using balanced field T/O. The only distance provided is the balanced field length (distance to accelerate, abort the T/O at V1 and decelerate). You must choose the right curve, depending on the number of engines (twin, tri or four-engine).
Jet / propeller. There are two distance provided and you may need both. Ground roll is the distance until the aircraft leaves the ground (liftoff); 50 ft is the ground roll + the distance to climb to 50 ft.

See also:

What would be the ground roll and total distance to clear a 50ft obstacle given these conditions?
How is minimum runway length related to V1?


Vmc is not the speed in which you can maintain altitude, it’s the minimum speed in which you can still maintain directional control with an engine inoperative in a twin.  Vmc is a design specification and not a maneuvering speed which is established by the manufacturer according to the design requirement of the aircraft.  The actual minimum control speed for a given situation, Vmca, varies based upon a number of factors, including density altitude, loadout, aircraft configuration, etc.  Vmca can be determined by doing a Vmc demonstration, which is a required maneuver to be demonstrated for an airman certificate operating multi engine airplanes.

Critical altitude is the altitude at which above this a turbocharger or supercharger can no longer maintain the maximum design operating manifold pressure for a reciprocating engine.  It is an important factor if you need to know the maximum power output of your engine at any given altitude for climb requirements, ability to attain and maintain an altitude to clear terrain and obstacles, etc., no different than knowing the available power for an normally aspirated engine.


What does a passenger aircraft galley ('kitchen') look like?

An aircraft Kitchen is known as the Galley and the picture is from a Lufthansa A380.

Some equipment you will see here are:

Food Oven, the door with a black knob in the middle of the picture.
Coffee Machine, with the pot, in the right side of the picture.
Large Trolleys, filled with food and/or drinks, on the floor. Weight about 25kg empty.
Trash Bin, the darker grey unit on the right on the floor. Wheeled off like everything else. Some have proper trash electric trash compactors as well in trolley format.
Fuse Panel, located in the middle along the top row. There is in general a fair bit of power going into this area.
Smaller Storage Containers, that can handle drinks or bottles for instance.
General Storage Space: The galley also provides a bit of space for anything from the children's toys and newspapers to emergency equipment. You can see some compartments for this in the upper-left corner and a symbol that a smoke hood is stored in one of them.

Quick design comment:

Aircraft galleys are hotspots for corrosion due to the liquid in the area and is the cause for particular attention during maintenance. Most aircraft galleys are generally very similar in design.

  Galley equipment comes in 2 basic universal standards - namely ATLAS and KSSU. These have their origins in legacy maintenance resource pools (ATLAS = Alitalia, TAP, Lufthansa, Air France, Sabena and KSSU = KLM, Swissair, SAS, UTA) and have subsequently developed into industry standards to enable modular equipment interchange.

These standards for instance specify the height, width and depth of trolleys. I gather that ATLAS standard is more prevalent (80% of galleys by one source) but both exist. Other ideas and concepts have popped up but since changing the stuff is very expensive there's not been a real push for it. I think I've also read that the original standard was pretty well thought through.

Naturally, this is a long-distance galley that will serve usually two meals. Equipment and size are scaled to the needs of the airline and can vary greatly between operators.


How to approach flying a new aircraft?

Find an instructor. Period.

Your instructor will, based on your past experience, guide you through the transition. For example are you going from Cessna 152 to 172? Or Cherokee to Cessna? Do you have experience with manual trim? Glass cockpit experience? These are just some examples. The process is so dynamic & variable that one cannot give a concrete answer here.

Say you have a PPL, and you want to exercise your privileges on this new aircraft. Your task is simple: demonstrate that you can perform what a PPL is supposed to perform if you were to do the checkride in that aircraft. You can expect to go through the entire PPL syllabus, only at a much faster pace because (hopefully) you understand every concept, it is just the matter of applying them to a new aircraft. Your instructor will not have to explain theories to you; it will be a lot more flying and a lot less ground school.


After an emergency landing, what procedures should the pilot follow?

There seem to be two parts to your question. First, what practical steps can I take on the ground immediately after landing? Second, which authorities must be notified?

For the first point, there are just too many scenarios to have a single answer but basically you should immediately check for injuries or damage to property and activate the emergency services if required. After that, secure the aircraft to prevent any further damage, call your insurance company and inform the aircraft owner and local property owner (as applicable). I'd also suggest giving your family a call rather than have them hear on TV news that you were "in a crash landing".

There are more dramatic possibilities, of course: if you ditched or landed in a remote area or in extreme weather then actual survival could be your highest priority. But that's a topic for another site.

For the second point, at least in the US it's possible that you don't have to notify anyone. If no one is hurt, nothing is damaged, and none of the incidents requiring immediate notification occurred (see 49 CFR 830.5 and the AIM 7-6-2) then there's no legal requirement to inform anyone. The authorities in this case would be the NTSB, not the FAA, by the way. There's a more detailed discussion of these requirements here.

An additional concern that I know nothing about is liability and other legal issues. Getting legal advice - e.g. from your insurance company or AOPA - would probably be a good idea whatever the circumstances.


Can people who suffer from motion sickness become pilots?

The short answer is yes. I can't answer all your questions in detail, but here's some US-based information.

First, is it disqualifying? According to the FAA, if a candidate for a medical says he suffers from motion sickness then "a careful history" is required, and if the person requires medication then FAA approval (i.e. a special issuance) is needed. So it all depends on the person's individual situation, but it is definitely possible to get a medical, even if you require medication. Motion sickness also seems to be fairly common in new pilots, by the way:

  Approximately 10% of all students taking flight training will become
  airsick at some point during their first 10 flights; 15-20% of these
  will have a severe enough form to interfere with their control of the
  aircraft.

Second, are there alternatives to medication? The FAA has a video about motion sickness and how to deal with. I haven't watched it but the description implies yes:

  This video provides practical advice on diet, medications and other
  exercises to help cope with this potential problem

Wikipedia also mentions various treatments although some (like head-mounted displays) seem impractical for civil aviation at least.

Third, do pilots adjust over time? Apparently, yes. This FAA document says:

  The experienced or acrobatic pilot is conditioned to withstand abrupt
  attitude changes that a passenger or helicopter pilot might not have
  experienced.

  [...]

  Continued gradually escalating exposure is the most common process for
  facilitating adaptation. Several days and repeated sessions of flying
  usually conditions the patient to the new environment.

That exposure would also be an alternative to medication, of course. And Sami's answer has some interesting personal experiences.

Finally, are pilots taught techniques to stay focused on flying? Instrument rated pilots are trained to ignore their physical sensations and focus fully on their instruments instead. But that training has nothing to do with motion sickness as such, and I have no idea how pilots who do suffer from motion sickness are affected (or not) when flying on instruments.


What is the division of tasks among the control towers at Chicago O'Hare airport?

As mins pointed out, the four towers you are asking about:

Old tower, no direct responsibility
Center tower
South tower
North tower

The airport directory (accessible from AirNav) breaks out the different tower and ground frequencies.

TWR N - 9L/27R
TWR C - All others
TWR S - 10R/28L

This makes sense, as the north and south towers shown on the AD are really only close to those applicable runways. The center tower is located where it can handle the rest. The old tower is not labeled.

The ground control is also split between the towers. I couldn't find a good reference for the division of responsibility there, but I would imagine that it would be similar to that of the towers, only controlling the taxiways associated with those runways, which are hard to see from the center tower.


What is the efficiency of running an electric motor from a gas generator?

I know a lot of small aircraft engines weigh around 150kg and several
  use gear boxes as well.

Almost no piston aircraft use gearboxes. The only one that I know of that ever did was the Porsche Powered Mooney PFM which was largely a failure overall, with the gearbox being often cited as an issue. Smaller turbo-prop planes do use gearboxes due to the super high RPM range of a turbine but those are generally larger than the ones that seem to be in question here.

  So Does this mean you could save the weight to make the plane electric
  but not battery powered or is the generator simply going to be too
  inefficient?

As mentioned the issue here is simply weight and line loss. You are taking mechanical energy converting it to electrical, bussing it somewhere then converting it back to mechanical. There will always be line loss in a process like that when you don't really need it (since you need to spin the prop to begin with). Gas-Electric (be it diesel or gasoline) is advantageous as you can drive full torque at 0-RPM which is useful when getting a giant freight train rolling but does not provide a ton of benefit to light aircraft. You are also introducing at least 3 major points of failure (engine -> generator -> motor) to a system that previously only had one.


Which kind of stability do aerobatic aircraft have?

If you are serious about designing an airplane that will one day fly and certify, you should, to the very least, read up Raymer, Aircraft Design: A Conceptual Approach. It has a chapter on stability & control, and would be a good introduction to the lingos.

More in depth coverage can be found in Etkins, Dynamics of Flight. It's pretty much the bible for S&C engineers.

Once you feel like you have the theory down, design guidelines for conceptual design (even preliminary design) can be found in Roskam, Airplane Design.

Since design goes hand-in-hand with certification requirements, a knowledge of 14CFR Part 23 and AC 23-8C wouldn't hurt.


Would in flight engine failure of the passenger jet be reported?

To certify any Commercial Jet Plane worthy of flying,

  a 2 engine plane must be able fly with just 1 engine running

  a 3 engine jet like the Lockheed L1011 or DC10 with just 1

  a 4 engine jet with just 2. Although not a requirement, the 747, A380  could fly on one engine but are not be able to maintain the cruise altitude indefinitely and will eventually become  long-range gliders so they must land immediately.

  The landing approach and procedures vary on how much the plane weighs prior to landing.

Would the passengers be notified, asking to take the brace position during landing?

Brace Positions are only assumed on impact emergencies, like crash landings. Losing an engine doesn't mean you are going to crash so no brace will be assumed.

Would such event have an accident investigation report?

There will be an investigation but if the plane landed safely it wont be filed as an accident. The plane plus the engines passed its FAA, EASA, etc Certification so it may be a number of reasons why the engine malfunctioned, like bad maintenance, faulty parts etc.

This is an extract from wikepedia -- http://en.wikipedia.org/wiki/Turbine_engine_failure

  Shut downs that are not engine failures

  Most in-flight shutdowns are harmless and likely to go unnoticed by
  passengers. For example, it may be prudent for the flight crew to shut
  down an engine and perform a precautionary landing in the event of a
  low oil pressure or high oil temperature warning in the cockpit.

  However, passengers may become quite alarmed by other engine events
  such as a compressor surge — a malfunction that is typified by loud
  bangs and even flames from the engine’s inlet and tailpipe. A
  compressor surge is a disruption of the airflow through a gas turbine
  engine that can be caused by engine deterioration, a crosswind over
  the engine’s inlet, ingestion of foreign material, or an internal
  component failure such as a broken blade. While this situation can be
  alarming, the condition is momentary and not dangerous.

  Other events such as a fuel control fault can result in excess fuel in the engine’s
  combustor. This additional fuel can result in flames extending from
  the engine’s exhaust pipe. As alarming as this would appear, at no
  time is the engine itself actually on fire. Also, the failure of
  certain components in the engine may result in a release of oil into
  bleed air that can cause an odor or oily mist in the cabin. This is
  known as a fume event. The dangers of fume events are the subject of
  debate in both aviation and medicine.

Would this report later be available for general public, as are the reports of various significant air disasters?

It depends, as you read above the flight deck crew may shut down an engine because of low oil pressure. Would that have significance of becoming public knowledge?

However as an example, if the problem of an engine failure escalates to the manufacturer then the airline may ground the fleet and that then becomes public knowledge and the reason why because the airliner would give media statements.

It all depends on the severity of the problem. Like this one that got reported --- http://www.b737.org.uk/accident_reports.htm

  20 August 2007; B-18616, 737-800, 30175/1182, FF 11 Jul 02, Okinawa,
  Japan:

  Engine #1 caught fire shortly after docking destroying the aircraft.
  No fatalities. The cause was the detachment of a slat pylon bolt which
  fell off and pierced the fuel tank which leaked and ignited. According
  to the JTSB the washer that should have held the nut in place probably
  detached during maintenance 6 weeks before the incident. The design of
  the nut has since been changed to limit the likelihood of detachment.


Steep turn: do we need rudder once we rolled into a bank angle?

No.  You use the amount of rudder needed to keep the ball centered. No more no less.  Most of the rudder requirement is to correct for adverse yaw, and is only required while the aileron is being applied.
If you are in a steep turn, you may find you need to apply aileron out of the turn to hold the bank angle if the airplane has a tendency to "overbank".  You might need to apply "top rudder" in this case, but only because adverse yaw from the top aileron will be making the nose yaw toward the turn and the top rudder is needed to align the tail with the nose in the airflow, to keep the ball centered.
The muscle memory activity that needs to be ingrained is left aileron, left rudder and right aileron, right rudder, depending on how bad the adverse yaw is, taking out the rudder input with the removal of the aileron input, with adjustments as required.  Your feet should just be squeezing this way or that way to center the ball, period.
Elevator/power (and aileron) is the only tool for altitude/attitude control in the turn (by "and aileron" I mean that once bank gets really steep, top aileron is often necessary to prevent the elevator application from just steepening the bank and tightening the turn - if you are targeting a 45 deg bank, this should be instinctive and you will be applying top aileron as required without thinking about it).
Use of "top rudder" rudder to prevent the nose from dropping, as opposed to just keeping the ball centered, is a cross control maneuver that results in a slipping turn (the ball will move to the low side), and if you stall out in a slipping turn, you will roll over the top as the outer wing stalls first and start to spin.  Many pilots have been killed by using "top rudder" as attitude control while turning to final and finished their lives right there.
I should also note that you can use a slipping turn to lose altitude on the turn to final, so you are in fact cross controlled with into turn aileron and top rudder, but this is a special altitude loss maneuver where you are making no attempt to maintain pitch attitude or altitude, just letting the nose fall through.  Done properly, there is no stall risk when doing a slipping turn (you aren't pulling and in fact you might actually push a bit), as can happen if doing a level steep turn.
So don't overthink it.  Just use your feet to keep the ball centered at all times unless you are side slipping on purpose, and get yourself into the automatic habit of squeezing left rudder with left aileron input and right rudder with right aileron input, and no rudder with no aileron input (but making applications as necessary if the ball drifts off).  A 172 needs very little rudder application to maintain a coordinated turn so it should just be little squeezes of rudder.
If you learn to fly gliders, where LOTs of rudder is needed to do the same thing, these actions become well ingrained because you have to, to get the damn thing to fly straight at all, which is why I always recommended learning to fly in gliders first.


Backup plane for checkride: Can it be a different model?

I came to the same conclusion as you, I don't see anything keeping you from going. You meet the requirements of 61.107 and 61.109, you have recent experience in both aircraft, and as far as make and model, they're both PA-28's. That's like going from a 172B to a 172S: it's the same make and model, Piper just makes it a little less obvious with their nickname and number combinations. If you had trained in a Warrior 160 and an Arrow, it would be a bit different, but only as far as requiring an additional endorsement.


Planes returned to base after dumping fuel due toilet issues

An aircraft with full lavatory waste tanks can not continue on it's flight as it is a requirement to have a specified number of serviceable toilets on every flight.  It is usually the responsibility of the Purser or In Charge Flight Attendant to check the waste tank volume when they prepare for each flight. On most aircraft there is a control panel with a display that shows the actual waste volume.

Here are some possible reasons why the waste tanks became full:

They were not checked before the fight
They were not emptied on the ground
They malfunctioned and ran continuously
The display on the waste control panel malfunctioned

In any case these tanks can not be emptied while airborne, and the only course of action is to land and have the tanks emptied or serviced.

On a long haul flight like PVG to AMS the crew would not have been legal to continue their duty day after returning to PVG and the flight would have to be cancelled or delayed until a new rested crew could be found to operate the flight.


What is the difference between landing weight and end-of-mission weight?

End-of-mission is a time- (and case) dependent term. Your mission could end under a variety of circumstances. If your mission is to carry passengers from point A to point B and you have an uneventful flight, then end-of-mission and landing are the same thing. But (as stated above) if you have an emergency at some point, you might need to abort the mission. If this happens, then you are likely to end-up dumping as much fuel as necessary to get to your landing weight, because said end-of mission weight and landing weight will not be the same.

Here is an oversimplified example:
Aircraft AC has MTOW of 100,000 kg and a MLW of 50,000 kg. The same aircraft has to get from point A to point B, without releasing cargo or ordnance. During the mission AC burns 100 kg of fuel per minute. Ten minutes after departure the pilot realizes that he has forgotten his watch and needs to land immediately. Now after 10 min flight AC weighs 99,000 kg. Since the mission is about to end before MLW is reached (99,000 ~= 50,000), the captain can either dump some fuel or circle around until AC's weight is at most equal to MLW.


As was said in the comments above, it is the support structure for the engine as seen in this drawing:


Does 3D Thrust vectoring (TVC) provide improved maneuverability over 2D TVC?

Thrust vectoring allows to control an aircraft when the airflow over its control surfaces has separated. Before thrust vectoring, the range of angles of attack in which an aircraft could be controlled was rather restricted.

With the X-31, it was for the first time possible to control a completely stalled aircraft, which enabled much quicker maneuvering in order to get the nose pointed at an adversary. This was powerfully demonstrated by mock air combats with an F-18. The X-31 used a rather simple arrangement with three paddles at the engine exhaust, and this allowed to create both pitch and yaw moments. This makes it what you call a 3D thrust vectoring aircraft.

Modern thrust vectoring nozzles are round and allow to deflect the thrust by up to 20° in both pitch and yaw, making them also what you call 3D. However, this geometry will scatter radar waves in all directions, which makes it unsuitable for stealth aircraft. Therefore, stealthy designs can use only two straight vanes above and below the jet exhaust, which will create only pitch moments. This is what you call 2D thrust vectoring. When two engines are installed, differential deflection will allow to create limited roll moments, but the powerful side forces which allowed the X-31 to rotate its nose (and radar) quickly into the path of its adversary will no longer be possible.

Stealthy thrust vectoring will still allow to control the aircraft at all angles of attack, but the yaw rates possible with a regular thrust vectoring nozzle are no longer achievable. This, and the structural mass of a rectangular exhaust, are the distinct disadvantages of stealthy nozzle designs.


How do you choose a feature to line up on when approaching to land?

Probably the best thing to do is to start looking for your reference as you start to lose the runway under your nose. Hopefully at that point you'll be low enough to identify something that will stand out from the crowd all the way down to the ground. You may also favor choosing something closer in from the horizon at 2000AGL, to ensure you don't lose it behind the horizon as you descend. For me, flying out of Addison, it's pretty easy; the runway faces downtown Addison about 3 miles south-southeast (a row of corporate headquarters buildings along the Dallas North Tollway) which is far enough out to line up on but close enough and tall enough you'll see it right up until you pass the numbers. Flying into a more rural strip, you might have more trouble identifying a good reference that you can keep in sight as you descend.

Some potential issues with this general strategy:

Your reference point will lie well beyond the runway by design. Don't fixate on it; that will cause you to subconsciously stay higher than your intended glide path as you fly toward your reference, potentially overshooting the runway.
Your reference is a single point. That point and your aircraft make a line, which you want to be colinear with the runway. But, your aircraft is a moving point, so it's not necessarily true that you'll be in line with the runway even if your nose is on the reference point. Instead of one reference point, I'd pick two (even if they're not perfectly in line) and focus on keeping both reference points steady relative to each other.
If you can't see the runway, you may not be able to see surrounding visual aids like the glide slope indicators, which are just as important as staying lined up. Addison's PAPI lights are off to the right when approaching runway 15, which is stupid as my instructor can see them perfectly while I'm blind unless I nose down every few seconds to keep track (not an option without flaps).

While I wouldn't rely on it completely in VMC, if you have a VOR receiver aboard and the runway has an instrument approach, you can tune into the ILS frequency and use the "cross" alongside visual references to manage your approach during the time the runway is hidden from view. The ILS system is pretty well-standardized, while the visual references at each airport are not, so if you become accustomed to an ILS-augmented visual landing, the basic procedure can be applied to any airport.

The reasons I wouldn't rely totally on it include:

You're not instrument-rated (unless you are) so flying with your head in the gauges can easily kill you. Glance at it to ensure you're where you think you are, but rely on your visual references whenever you can.
You're not flying a pure instrument approach under IFR, so you still have to "see and avoid" even if you have tower staff spacing traffic around you (unless you ask for a "pop-up" instrument approach, effectively switching from VFR to IFR).
ILS availability/accuracy is not guaranteed in daytime VMC because the ILS critical areas are not required to be protected during these times. If you tell the tower what you're doing, they can advise ground traffic to use the ILS holds, but there may already be traffic in an ILS critical area and if so there's little the tower can do.
ILS may contradict visual indicators to varying degrees, because the ILS glideslope is projected from a different point along the runway than the PAPI/VASI array. You therefore shouldn't expect the ILS cross to be perfectly centered along the same path that gives you two white PAPI lights.
Radio-based ILS isn't available at every airstrip. In such cases you simply must fly a purely visual approach, and having relied on ILS to give you the proper glide slope instead of developing your sight picture will prove to be a crutch in such situations.


What is the relation between trim setting and constant airspeed?

Your friend is right.  Elevator trim isn't setting a pitch, it is compensating for control forces on the elevator, which vary with speed.  If you are trimmed for level flight at 100 kias and reduce power the plane will initially slow.  As it slows the trim will cause a nose-down moment causing the plane to pitch down.  Given no input, the plane will equilibrate at whatever nose-down pitch is needed to regain the forces it was trimmed for, which means speeding back up to 100 kias.

You are correct that to maintain 100 kias with reduced power the nose should be lowered, but the trim will take care of that for you.

You might have a misconception about how trim works, based on your argument.  A typical trim setup in light airplanes is essentially another control surface on the elevator:

The elevator is the large control surface and that smaller control surface is the elevator trim.  When you adjust the pitch trim you are adjusting this trim tab which provides a force on the elevator that counters aerodynamic forces.  This is why the airplane responds in pitch to maintain constant aerodynamic forces (e.g. constant indicated airspeed) for a given trim setting.

You can test this in the airplane easily.  Take your plane up to the altitude you practice maneuvers at, set 75% power (or some other number) and trim for straight and level.  Add power and watch the plane climb, decrease power and watch it descent, both without touching the trim.  Go back to straight and level and trimmed and accelerate without climbing -- note you are having to retrim as your speed increases.  Decelerate without descending  -- note you are retrimming as your speed decreases.


Why do supersonic planes fly higher than subsonic airliners?

It was necessary for Concorde to fly much higher, and not a voluntary decision. A higher cruise altitude increases the demands on the airframe (examples: Combustor size, pressurization) and is only accepted when it comes with sufficient benefits.

An airplane needs a certain wing area for realistic take-off and landing distances. Also, details like the maximum tire speed need to be observed, so the wing area must be large enough to create enough lift at low speed.

Lift is proportional to the square of airspeed and air density. The faster a plane flies, the lower the density can be to create sufficient lift. By flying more than twice as fast as a Boeing 737, the Concorde could fly at a fourth of the density by this reasoning. Air density (symbolized by the Greek letter $\rho$) halves approximately with every 5500 m of altitude increase.

However, the slender wing needed for low supersonic drag is not as efficient as the sub- / transsonic wing of a 737, so a little more density was needed for the Concorde. The 737 is designed for cruise between 8000 m ($\rho$ = 0.526 kg/m³) and 12000 m ($\rho$ = 0.312 kg/m³), and the Concorde flew between 16500 m ($\rho$ = 0.154 kg/m³) and 18000 m ($\rho$ = 0.121 kg/m³).


It is the Airbus A300-600ST (Super Transporter) Beluga, which is a version of the A300 wide-body airliner modified to carry aircraft parts and oversized cargo.

Source: berlin-aviation-forum.com

The nose is shaped like that as the upper portion is basically a cargo hold and is used to transport oversize cargo, especially aircraft parts.

"F-GSTB - 2 Airbus A.300B4-608ST Beluga Airbus (8634655670)" by aeroprints.com. Licensed under CC BY-SA 3.0 via Commons.

The cockpit was lowered below the cargo deck so that the cargo area could be loaded without having to disconnect any of the vital electric and hydraulic lines running to the rest of the plane. However the A300’s lower fuselage, wings and landing gears were retained.

The following image shows the changes that were made in the nose section from A300 to the Beluga.

Source: allaboutguppys.com


May planes be flown above the maximum certified altitude?

The Max Certified Altitude is the highest that the manufacturer has test-flown the aircraft to. (And the 100ft simply makes cruising at FL410 legal.)

If you want to take the airplane above the MCA, and you can actually get it up there, then you now become a Test Pilot, but without the Test Pilot pay and insurance cover. Good luck!


What are the flying accommodations in Silicon Valley for private pilots?

Moffett Field is still primarily a Federal airfield. They'll take some corporate jets, but not GA, and prior permission is required. All requests go through Planetary Ventures LLC, which owned by Google.

San Jose is a large international airport, but it appears to have no landing fee, though you'll pay a ramp fee unless it's waived. Some AirNav reviews of the FBO give you an idea of what to expect, and you could contact them for further information.

There are a number of GA airports to choose from though. Including:

Reid-Hillview
Palo Alto
San Carlos

All of these airports have flying clubs and should offer instruction.

Along with others somewhat further away (a few examples include Half Moon Bay to the Northwest, San Martin to the south, Hayward Executive and Oakland International to the east), depending on where exactly you'd like to be.


What rating can I add to a commercial certificate with the least time/effort?

Jack Brown's Seaplane Base offers single engine seaplane ratings at private and commercial level.  It takes 2 full days and costs between 1400 USD and 2300 USD depending on your choice of training aircraft.

From their website:

  SES Rating

  We offer three options of planes for your SES training at the private
  or commercial level, both of which include: 1.5 hours of ground
  instruction, 5 hours of dual instruction, the check ride and the
  examiner’s fee.

  Training in the Piper J3-Cub on floats,  1,400.00.

  Training in the Maule M-7 on floats,     2,300.00.

  Training in the Super Cub on floats,     1,850.00.

  If additional flight instruction hours are required they are billable
  at the hourly rate of the aircraft (listed below).

They are located in Winter Haven, FL.


What is this sound from Airbus aircraft before take off?

According to Ask the Pilot:

  Almost every frequent flyer has encountered this sound at one time or
  another. [...]

  It happens on twin-engine Airbus models: the A320 series (includes the
  subvariants A319 and A321) and the larger A330. [...]

  What you hear is a device called the power transfer unit, or PTU,
  which is designed to ensure adequate hydraulic pressures during
  single-engine operations. [...] Since it is activated only when the
  pressure falls below a certain level, the PTU cycles on and off, on
  and off, on and off.

  [...]

  Some Boeing aircraft also employ a PTU, but the operation is slightly
  different and it doesn’t bark like a dog.

  Another noise peculiar to Airbus models is a shrill, prolonged whine
  heard at the gate prior to departure and again after landing. This is
  an electric hydraulic pump used to open and close the cargo doors.


Why does the Hinch Mountain VOR (as an example) have void areas below certain altitudes published in the U.S. Chart Supplement?

Either multipath including refraction induced  errors  or blocking/masking by terrain.


Does "resume own navigation" also mean "altitude your discretion"?

At this time, the definition of "resume own navigation" is very varied from group to group. ATC Controllers say that if there is an altitude restriction, they have to clear it. So safest thing to do is to ask for clarification if you had an altitude restriction/not told "altitude your discretion" that would continue into the "resume own navigation" exactly what you are doing now.

Source


What does scheduled departure time exactly mean?

"Scheduled departure time" is not a term used in the operational environment. It is a term you will find on the passenger side of things, and means the time at which the aircraft is scheduled to leave the departure gate.
There are several different operational terms related to departure time:

ETD, Estimated time of departure. The estimated time at which an aircraft will become airborne.
SOBT, Scheduled off block time. The time that an aircraft is scheduled to depart from its parking position. More or less identical to "scheduled time of departure".
EOBT, Estimated off block time. The estimated time at which the aircraft will commence movement associated with departure.
TOBT, Target off block time. The time that an aircraft operator / handling agent estimates that an aircraft will be ready, all doors closed, boarding bridge removed, push back vehicle present, ready to start up / push back immediately upon reception of clearance from the TWR.
AOBT, Actual off block time. The time the aircraft pushes back / vacates the parking position.
TSAT, Target start up approval time. The time provided by ATC taking into account TOBT, CTOT and/or the traffic situation that an aircraft can expect to receive start up / push back approval.
ETOT, Estimated takeoff time. Forecast of time when aircraft will become airborne taking into account the EOBT plus EXOT.
EXOT, Estimated taxi-out time. The estimated time between off-block and take off. This estimate includes any delay buffer time at the holding point or remote de-icing prior to take off.
TTOT, Target takeoff time. The Target Take Off Time taking into account the TOBT/TSAT plus the EXOT. Each TTOT on one runway is separated from other TTOT or TLDT to represent vortex and / or SID separation between aircraft.
CTOT, Calculated takeoff time.A time calculated and issued by the Central Flow Management unit, as a result of tactical slot allocation, at which a flight is expected to become airborne.
ATOT, Actual takeoff time. The time that an aircraft takes off from the runway.
ATD, Actual time of departure. Used either to have a meaning identical to ATOT, or AOBT, depending on context.

I've probably missed some, too.


How does dropping ordnance affect the weight and balance of the aircraft?

the aircraft I worked on in the army were deadlined whenever 1% of total aircraft weight was removed, requiring either the part to be reinstalled or a total reweigh prior to next flight.

That's for internal equipment, which will affect the empty CG data.

All aircraft lose weight during a trip. Aircraft designed to lose a lot of weight all of a sudden ( C-5 airdrops, B-52 carpet bombing ) have the details and limits calculated during the design. In the case of bombers, the ordinance will be hanging near the wings and will have a specific release order, usually back to front.

A tailgate aircraft dropping something will also have very specific procedures based on the weight of the pallet going out the back door. If it's delivering pizzas the procedure is along the lines of "whenever, dude". If it's a tank, it has to be positioned and locked down until the moment of release.

The above is very noticeable by the flight crew.

If the load stays (or gets stuck) on the back ramp, you're usually done. I used to skydive - 10 people on the back end of a smaller tailgate like a Casa can and do cause the plane to stall. The rules were stay at the front until it's your turn, then position and exit in a prompt manner. If the buzzer goes, let go NOW. Unlike a cargo plane, jump planes have 12,000 feet to recover from the stall.


Is the 737 Max's AOA disagreement warning light an actual light?

In the B737MAX, being a full glass cockpit, the light 'AOA Disagree' is indicated by an alert on the PFD (rather than a physical bulb). This is why Boeing was selling it as an option: it is just a software change to show or hide 'AOA Disagree'.

Image taken from B737 MAX FCOM 10.10.33


Why do different manufacturers recommend different throttle settings at startup?

It's just a ballpark value that someone decided on during testing, that provides enough air to the engine to let it start and run with a rich primed mixture, without causing too much initial RPM.  A quarter inch here, and eighth inch there, it's all good as long as it doesn't cause the engine to burst into life at high power, and nobody expects you to sit with a measuring stick to get it exactly right.
It's not a good idea to start an engine with a very high throttle setting, because high rpm before there is sufficient oil flow = bad in the long run.  Crank and rod bearings need to be fully pressurized before any significant load is put on them. Cam followers need to be well coated in oil before they spin at more than minimum speed (especially with Lycomings).
Most engine wear happens in the first 15 seconds of starting, when the oil flow is inadequate and bearings, piston rings, cam lobes and gears etc are running on only a residual oil film.  Once a plain bearing is fully pressurized with oil, there is no metal to metal contact and the life of the bearing, in theory, is infinite.  If you ran a 2000 hour TBO engine with just one start and let it go without ever shutting down and just kept it supplied with fuel and oil 24/7, it would run far far beyond its normal TBO (although it might need cylinders at some point as valves wear out).
My personal practice is the use the absolute minimum throttle opening that will let the engine start, and let the engine tick over at minimum speed until I see normal oil pressure, before I go to a warm-up RPM. When an engine is warm, that usually allows starting with the throttle completely closed. Oil gets to where it needs to pretty fast; it's just that initial 10-15 seconds that's critical.


How does an airplane do a Kulbit manoeuvre?

The Kulbit maneuver is a variation on the Cobra maneuver (Pugachev's Cobra) with a higher pitch rate and continuous positive pitch rate throughout the maneuver. It requires two things:

A docile pitch behavior of the airframe over the full angle of attack range of 360°. Docile means that the pitch moments stay low and do not change abruptly with the angle of attack.
Thrust vectoring nozzles to keep the pitch rate up.

An electronic flight system is helpful to make execution easier, but is not strictly required. Also helpful is an engine-intake-combination which does not stall the compressor if the outer flow is reversed briefly. As you can see, the control surfaces only play a minor role - they are only important initially to start the pitch-up motion. This is done by negative elevator and/or positive canard deflection.


What is this aircraft with wings seemingly fixed the wrong way?

It looks like the Cessna Citation II of which hundreds were built.

By Adrian Pingstone - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2971403

The wing profile is trapezoidal, as can be seen in the image below.

Image from avistar.org

This kind of wing design is found in a number of aircraft, for example the other Cessna Citation series aircraft and the Embraer Phenom 100.

By Josh Beasley from USA - Private - Embraer Phenom 100 - N629AS (26/365)Uploaded by tm, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=25761759


How does the propeller position affect the effectiveness of control surfaces?

A propeller has more effect on a control surface behind it, than on one in front of it. That's because the propeller pulls in air from a large area in front, and ejects it in a relatively narrow stream behind. Since the mass flow rate is the same on both sides, the air in front moves fairly slowly, and the air behind moves faster. Forces on a control surface in an airflow depend on the square of the airspeed, so a control surface in the fast-moving air behind the propeller will deliver larger forces for a given deflection than one put in the slower-moving air in front. Look up Axial Fan Design on Wikipedia, for a cross-sectional view of the airflow through a propeller.


Does downwash increase or reduce lift generation?

Downwash is behind the wing and is the result of pressure differences between the top and bottom of a wing.  Although the energy conservation bookkeeping says the plane goes up and the air goes down, the main driver of lift is pressure differential.  True to Bernoulli, the angled bottom wing slows and increases air pressure beneath the wing.  This is "bottom lift" that even simple flat plates have.

Airfoils also deflect air upwards and away from the top of the air foil, creating additional lift above the wing.  Downwash is created by the movement of air from higher to lower pressure as the wing goes by, filling the void where the wing was.  This constant process is known as circulation.

Ground effect may not be directly related to downwash, but may be indirectly, as the ground and the downwash stream may create enough of a "fence" to slightly raise the pressure under the wing.  A Cessna 172 has a wing area of $174 feet^2$.

$174 feet^2 × 144 inches^2/foot^2= 25056 inches^2$

A pressure increase of 0.01 psi from ground effect adds 250 extra pounds of lift!

Ground effect is also said to be caused by the wing tip vortices being disrupted by their proximity to earth.