Are magnetic compass acceleration errors due to the southern side of the compass being weighted?

Some compasses are counterweighted to decrease magnetic dip. Older and/or cheaper compasses for land navigation are this way. Many to most are not weighted, especially in aviation compasses. Weighted compasses would require different compasses for the North and South hemispheres. Instead, aviation wet compasses are built with the low friction mounting point above the CG and magnetic bar. This causes the CG to move to the South polarity end of the compass assembly when the magnetic bar dips downward to the North Pole and to the North polarity end when dipping towards the South Pole. I like this article that explains this phenomenon.

Several decades ago, my unit had the opportunity to train with the Australian 3rd Para Regiment in Australia. Many of us had been using personally owned GI lensatic compasses because the tritium markers worked better than the newer, issued lensatic compasses. We were warned that the older models may not be accurate down under due to them being Northern Hemisphere compasses instead of the universal ones. I did not understand the reasoning for this until many years later.


Why don't nose landing gears have brakes?

The assumption is wrong. Some planes indeed have nose wheel brakes.

The reason why so few planes have nose wheel brakes is that

The braking force of a brake cannot exceed the weight carried by the corresponding wheel multiplied with the friction coefficient. A nose wheel carries much less weight than a main wheel, because the main wheels are much closer to the center of gravity. There is more force on the nose wheel during deceleration, but still much less than the main wheels carry.
The nose wheel brake itself, as well as stronger structure, mechanisms and wheels would add more weight to the nose of the aircraft.
Nose wheel braking reduces the stability of the decelerating plane. This could be controlled in various ways at the cost of increased complexity.

For the aircraft designer it is a trade off: is is worth extra cost, weight and complexity for reducing the braking distance by a small amount?

Note that there are planes where even some of the main gears are not equipped with brakes, for instance the A380, where no more brakes are required to fulfill the requirements.


What is the purpose of the shuttle valve in a Piper Arrow's landing gear system?

The shuttle valve is actuated by high or low pressure depending on what you select, gear up or down. It routes the hydraulic fluid to the bottom of the cylinders to raise the landing gear with high pressure, or to the top of the cylinder to lower them with low pressure and to allow the fluid to return to the reservoir.


Are passengers really not allowed to change seats before take-off due to weight and balance?

The crew gave you the correct reason, but it would had taken a co-ordinated effort from the majority of the passengers to upset the aircraft's balance.

But in smaller aircraft even a single person moving around can shift the center of gravity outside its safe limits. The de Havilland company once produced such an aircraft, the DH86 Express. Wikipedia reports:

  On 2 October 1935 Holyman's VH-URT Loina was also lost in Bass Strait,
  again with no survivors. This time a significant amount of wreckage
  was recovered from the sea and from beaches on Flinders Island.
  Investigation of the wreckage revealed a section of charred carpet on
  a piece of cabin flooring from just ahead of the lavatory door. It was
  thought possible that a small fire from a dropped cigarette had led to
  someone running aft suddenly to stamp it out – the sort of sudden
  change in weight distribution that could set up a fatal loss of
  directional control while the aircraft was on a low-speed landing
  approach.

A dramatic example what a shifting load can do to the controllability of an aircraft was National Airlines Flight 102, a Boeing 747-400 freighter conversion which took off from Bagram on April 29, 2013. The most likely cause was insufficiently secured payload which shifted back when the aircraft pitched up during take-off. A single passenger will not be as heavy as a MRAP, but several of them moving over a significant part of the cabin length in combination with a position of the center of gravity close to the limit could well upset the flight.

CG at the forward limit, passengers moving to the front: The aircraft will need higher speed and much more elevator deflection for lift-off. Especially in combination with an engine failure late in the take-off run, a crash is a distinct possibility.
CG at the rear limit, passengers moving to the back: The static stability and, in manually controlled aircraft, the stick forces are reduced. Flying the aircraft needs more attention, and in extreme cases the aircraft will become longitudinally unstable.

In any case, the pilots need to adjust trim.


How do engines cope with various intake airflow speeds?

The airplane isn't aware of the winds. It just moves through the air mass at a certain speed, and if the air mass is moving it adds or subtracts from the aircraft's speed over the earth.

Drive your boat along a river with a 10 mph current upstream, then downstream, both at 25 mph on the boat's speedo.  The whole time your boat's showing 25 and the hydrodynamic forces acting on the hull are 25 mph forces. What's your speed relative to the shoreline going upstream compared to going downstream?  15 going upstream and 35 going downstream right?

Exact same thing with airplanes.  Navigating ships allowing for ocean currents is exactly the same as navigating airplanes in "air currents", they have "tailwind" currents and "headwind" currents and cross currents where you have to aim for point X to actually proceed to point Y, except things are happening in slow motion in the ship.


Why is there a relationship between maneuvering speed and weight?

stall speed goes up as weight increases. Since maneuvering speed is set a certain margin above stall speed, it goes up too as weight increases.


How can you identify an Airbus or Boeing from the inside?

Look at the safety card in the seat pocket in front of you:

As a side note, it will be beneficial to read the safety card as well.


Which commuter flight was forced to land in a cornfield in '96 or '97?

From the Los Angeles Times newspaper, Jan. 21, 1989.

  BUENA VISTA, Colo. — A commuter plane carrying 26 passengers lost power Friday and made an emergency landing in a cornfield, but no one was injured, authorities said. Airline officials had not determined what caused the engines of the United Express plane, a Convair 580 twin-engine propjet, to shut down.

Here is the link: LA Times


Why are there out-of-date tower frequencies on the VFR sectional chart, without a NOTAM?

It's not a printing error. FAA sectional charts are updated only once every six months. In order to to reduce the number of NOTAMs due to sectional changes (which can number in the hundreds between cycles), the FAA provides a section in the Airport Facility Directory (AFD), titled "Aeronautical Chart Bulletin" that identifies changes that have occurred since a chart's publication. Pilots should check this section on each AFD update for changes on their intended route of flight. Once the change is posted in the AFD, the respective NOTAM is taken down.

Here is an image of the applicable AFD page for Salinas, as of the date of this answer:


Are modern airliners still stressed-skin aircraft?

Yes, absolutely. The skin transfers shear stresses between the stringers or longerons which run lengthwise along the fuselage and transmit tensile or compressive stress. Cutouts and openings (for doors and windows) need special local reinforcements, so the reduced structure can still withstand the loads.

Equally, the wing skin is the main element for the transmission of torsional loads. In today's airliners, the spar is part of the skin, but the wing skin ahead and aft of it is also a part of the primary structure.

Generally, stress follows stiffness. When a structure is loaded, it will deform, and those parts which withstand deformation most will carry most of the load. In the end, all parts which have similar stiffness will carry loads in proportion to their cross section. Since most of an airliner's structure is made from aluminum, it has the same stiffness.

See this question for one example clearly showing fuselage skin deformation.


What are these "winglets" on the roof of the 737?

In general, those are called blade antennas. They consist of a monopole antenna (a single rod sticking out of the fuselage) with an aerodynamic fairing around it.


Can a plane with air-breathing engines in level flight achieve enough velocity to make a single orbit?

No.

Currently the altitude record for a jet is 37,650m (This is a zoom and climb record, not sustained flight).

Ralph J sum up the issue pretty well, but let me add some data:

Ramjets are the kind of engines that looks the closest to what you want to achieve. They top out at 2km/s Orbital speed would be 7km/s. And that's with a minimal payload.

There is an inextricable issue with forgoing O2:

You need significant O2 to have thrust
You cannot get thrust if there is atmosphere (Drag+heating)

Lastly; to achieve an orbit, you need a circularisation burn, that can only be done outside of the atmosphere.

The lowest point of your orbit cannot be higher than the lowest burn performed.
Using only atmospheric O2; your orbit will be bound to reenter on achieving your first revolution.

(If you intend to achieve escape velocity however, this is not an issue anymore).


Why locate engines far from the fuselage in some aircraft, such as the SR-71?

From Wikipedia:

  Placing engines on the wing provides beneficial wing bending relief in
  flight. The further the engines are away from the fuselage the greater
  the wing bending relief so engines buried in the wing root provide
  little relief. Almost all modern large jet airplanes use engines in
  pods located a significant distance from the wing root for substantial
  wing bending relief.

One could imagine that, in flight, the wings are holding up the aircraft, but this causes a massive bending moment at the wing roots (just visualize  an airplane suspended by ropes from the wings). As such, is favourable to have the airplane body be as light as possible, and put as much mass (e.g., fuel) as possible on the wings, where the lift forces coincide (or at least, are closer to) the weight of the engine, reducing bending moment on the wing roots. This allows for smaller (and thus more aerodynamically efficient) wing structures.

As noted in the comments, placing the engines further away of course increases downwards bending moment when the plane has landed. However, this will be 1g by definition (at touchdown, the wings still provide lift (generally)), whereas during the flight, an airplane is designed to take up to 2.5g (and, I suppose not completely coincidentally, -1g).


VOR Ground Station is aligned with magnetic North. It emits two signals:

a 360° sweeping variable signal
an omni-directional reference signal

When an aircraft receives those signals, its receiver compares those and a measures the phase difference. This gives a precise radial position of the aircraft which is displayed on its Omni-Bearing Indicator (OBI), Horizontal Situation Indicator (HSI) or a Radio Magnetic Indicator (RMI), or a combination of two different kinds.

This picture shows the two signals:

Blue is 360° sweeping signal
Green is omni-directional reference signal


On FSX flight lesson on climbs and descents, what does "free ride" mean?

If I remember correctly most of those FSX lessons were done by Rod Machado.   He’s a good CFI but has a tendency to speak tongue-in-cheek about things. What he means by that is that by lowering the nose you can maintain the same airspeed but use less power to do it i.e. getting a free ride out of it. In truth what’s happening is that the airplane is compensating for the reduction of thrust by exchanging potential energy for additional kinetic energy, and it does this by descending.  It’s not exactly a “free ride” per se - energy is conserved after all - but the effect is similar to a car rolling down a hill whereby the driver does not need to give the engine gas to maintain a given speed.


Can thermals or high density altitude improve fuel efficiency?

For flight time and saving fuel, the density is not relevant. Density is relevant to distance covered if you need a set cross country distance rather than a set time. You would only want to set power to maximum endurance which will be very near best glide CAS, while best true airspeed and ground speeds would change with density the best endurance CAS would not.
It may also be advisable to plan relatively shallow descent angles so that the engine stays within a reasonably efficient power range. Climb with power low enough that you can keep it leaned.(after the initial takeoff and climb out, unless maybe you are at an excessively long desert runway)
Thermals could aid the flight time allowing even lower throttle settings but could also harm as they go both up and down, capturing the right current depends on the pilot's glider experience.
Now where I rent, fuel is included in the per hour price and the goal is usually to get a set distance or set of maneuvers in a minimum time. Just the opposite of what you propose.


How does the pressure change in the Air Cycle Machine?

Strictly speaking you're right, the authors used a brief and easy to visualise but slightly inaccurate phrasing. The blue bit is open to the cabin, and at the end of it will have cabin ambient pressure. At the beginning of it the pressure will be slightly higher, but very much lower than before the turbine.

The pipe diametre does not need to change for the pressure to vary. Air streams from high pressure to low pressure, upstream pressure will always be higher than downstream pressure, by an amount to overcome the friction forces.


In an Airbus A320, when alpha protection is active, is pitch protection no longer available?

In normal law « Alpha prot » has the highest priority, if AOA is less than alpha limit, teta (pitch angle) is limited between +25 and -15 at long run. At long run,  since in emergency descent you are allowed for a short time to go beyond - 15° pitch down, to do that you need to pitch down the side stick very quickly after having engaged a steep roll.

If AOA protection is active, I don’t see how you can exceed 25°or 30° pitch up, since the FBW will pitch down the aircraft to follow the AOA protection.


What is the procedure to contact EASA to evaluate the certifiability of a system?

DO-178 / ED-12C

Any software that executes on installed hardware in a type certified aircraft will need go to through DO-178C (or a similar process). The amount of effort involved depends on the safety criticality of the software functions.

Since this sounds like a new system without predefined System Requirements (such as those you would get from an OEM as part of the SAE ARP 4754A processes), those will need to be defined by your development process and then your Software (High Level) Requirements trace from those.

Here in the US, smaller companies will typically contact and work with the local ACO (Aircraft Certification Office) during the product planning stages to identify the product as following the DO-178C processes.

Larger companies, especially OEMs, tend to work with DERs (Designated Engineering Representatives) rather than directly with the ACO, as they may have dozens of different DO-178 projects going at one time.

EASA Software Certification

Guidance on the EASA Software Aspects of Certification can be found in EASA CM -SWCEH - 002 PDF

From that document, Panel 10 seems to be the part of EASA that you would work with, although I haven't found how a new applicant would go about contacting them yet.

  The EASA panel in charge of software and AEH aspects of certification.
  This panel includes at least one software and AEH expert (who is the
  coordinator) and, depending on the size of the project, may include
  additional software and AEH experts.

There is also a FAQ page for the application processes with EASA:

https://www.easa.europa.eu/the-agency/faqs/application-process


Why are commercial flights not equipped with parachutes for the passengers?

Qualification: I worked at a sport parachute center as an instructor for 10 years and I hold an FAA Master Parachute Rigger certificate. I believe that qualifies me as an expert on the subject.

The majority of the above other statements here are correct. In summary:

The door of a pressurized passenger plane cannot be opened in flight for the stated reasons.
the door of most larger passenger planes cannot be opened in flight after you depressurize the cabin because they swing forward. Push a sheet of plywood against a thunderstorm-grade wind and see how well you do. Now multiply the wind speed by 5.
even if you blow the door out with explosives, the chances of an orderly exit are slim. At airliner speeds an orderly exit is critical if you expect to survive the jump. Street clothes will be torn to shreds. Oh, and it's COLD up there.
you cannot depressurize an aircraft over 12,000 feet altitude without the passengers passing out rather quickly. If you can control the plane down to this altitude, you don't need the parachutes.
it is extremely difficult to exit an unstable aircraft that is built for sport parachuting (in-flight door, suitable handles, door already open). If the plane is spinning and you are beside the door you might get tossed out and then struck by other parts of the airframe. If it's a larger plane and the door (or you) are away from the current axis of rotation, good luck. Yes, jumpers have successfully exited a crippled jump plane. None of them want to try it again.
modern sport parachutes use steerable ram-air canopies. Jump one of these without any training and you will hurt yourself landing. Most emergency parachutes are round. Jump one of those without any training and you will break something when you land. 200 untrained people jumping ram-air canopies all at once will result in a number of collisions and entanglements, which are typically fatal for all involved.
exiting an airplane below 1000 feet is really not practical. I would do it IF a) the plane is currently under control; b) landing is not practical; c) It's really 1000 feet, not less; d) I'm sitting beside the door. Possible scenario is the engine goes boom and I know there's nothing but rocky land ahead of us. Of course my gear is already on my back ready to go, and I know how to use it.

There have been many cases of a jump plane experiencing engine problems on the way up. By the time the pilot turns around, the cabin is usually empty. There have also been cases where jump planes have crashed on takeoff. None of the (very experienced) jumpers on board thought about anything other than tightening the seatbelt.

Points I disagree with: (although they do not change the outcome)

Emergency parachutes (seat-pack types) are available for far less than sport rigs. Maybe $1,500 each. Weight around 8-10kg. Putting a purpose-built one on would be not much more complicated than a 4-point harness. This was seriously considered back in the 1950's - aircraft seats were designed with parachutes built in. Planes were neither pressurized nor fast back then. Think DC-3 era - the DC-3 makes a great jump plane, I have used one a few times.
maintenance costs would be no more than the escape slides, flotation gear or other similar equipment.


What restrictions are there to building a tower near a private airstrip?

According to this AC you dont need to light the structure,

  Any temporary or permanent structure, including all appurtenances,
  that exceeds an overall height of 200 feet (61 m) above ground level
  (AGL) or exceeds any obstruction standard contained in 14 CFR Part 77
  should be marked and/or lighted.

But the FAA does have special cases and since you are close to a strip they may require/recommend it,

  The FAA may also recommend marking and/or lighting a structure that
  does not exceed 200 (61 m) feet AGL or 14 CFR Part 77 standards
  because of its particular location.

Looks like you need some specific stuff to actually light it. Your local FSDO should be able to help out with what ever info you need. As far as I know these kinds of regulations don't change between public and private airports.

You can find the letter of the law for 14 CFR Part 77 here. The most applicable to your case is quite possibly,

  (3) A height within a terminal obstacle clearance area, including an
  initial approach segment, a departure area, and a circling approach
  area, which would result in the vertical distance between any point on
  the object and an established minimum instrument flight altitude
  within that area or segment to be less than the required obstacle
  clearance.

Even though you are not directly in line with the runway you may be in conflict with a potential traffic pattern or approach segment.


last 747 flight path, was this hand flown? How was this communicated with ATC?

I don't believe anyone could hand fly something that precise.  A series of waypoints could be entered in the flight plan in a "connect the dot" manner, then the autopilot could be put in NAV mode to fly the pattern.  Nothing that difficult about it though, it would just take some time.

If they are at 10,000 feet this could be done under VFR, in which case no "ATC Procedure" is necessary.  I am pretty sure though, that the flight would have communicated their intentions with ATC.

I am curious about area just off the end of the pointed nose.  I am guessing that they flew past this point and made a reverse turn, effectively creating a loop in the depicted track that is cut off in the picture.  Do you have a full screen shot showing this?  Because if it isn't there, then this was either all photoshopped, or flown, then the loop edited out later.  A 747 can't just turn on a point...


Are the CAA and FAA Class 1 medical certificates equivalent?

The CAA medical (UK or any other country with a CAA) is not equivalent to an FAA medical, you have to get an FAA medical to get a FAA license. The classes are similar but they cannot be used in place of the other. In the UK you can get an FAA medical from several AMAs.


Where does the Departure End of Runway (DER) exactly begin?

The picture you linked is from an FAA publication. As pictured the threshold is the end of the runway pavement, it is a thin line that separates usable runway from either taxiway, blast pad, grass, or an emergency overrun area. It is marked at night with a single row of green or red lights (depending on your direction). It can be displaced or reloacated from the original pavment but in this case it will have noticeable markings that include a well defined line marking the exact end. Some ends are usable for takeoff but not landing or vice versa but that is down to individual runways.

The paint bars near the threshold of an instrument runway are simply for visual reference to help indicate the width and length of landing zone during approach, they have nothing to do with takeoff or departure. VFR runways only have a number and dashed center line, no white bars at all.

To summarize: the threshold is a line not an area, it separates usable runway from non-runway, it may be marked with paint or lights but it can also simply be a change in surface such as tall grass to short grass. Standard departure obstacle clearance climb gradients are calculated with the plane at 35feet above the ground, directly over the threshold at the departure end of the runway.


What is the effect of uneven ground on ground effect vehicles?

The ability of a ground effect (air)craft to able to fly with (small) perturbations in height from the ground is called height stability. In general, height stability is achieved if the derivative of the lift coefficient with increasing height is negative. In this case, a decrease in height (due to waves etc.) causes an increase in lift. As a result, the aircraft is returned to its original height due to the increased lift (with the opposite happening when height is increased).

As the ground effect increases as the height decreases, designing the ground effect aircraft with height stability is not very difficult and most of the ground effect aircraft designed and operated have height stability. A good example is the Lun Ekranoplan, which returned to its height after the height was altered by approximately 0.5m (due to missile launch).

"Lun Ekranoplan" by Soviet Navy - Stock Archives of Soviet Navy. Via Wikipedia.

Also, the Sea state limitations are a scale phenomenon — the larger the ground effect aircraft, rougher the seas it can handle. The Russians (Soviets) have the most experience in operating ground effect vehicles and according to them, sea state limit for a 500-tonne aircraft is around 2.5 m and the safe operating heights in terms of mean wave heights is given by,

$h  = \frac{1.54 H_{\frac{1}{3}}}{2} +  0.1  c$

where,

$h$ is the vertical height measured from the mean wave height,

$c$ is the chord,

$H_{\frac{1}{3}}$ is the average of the 1/3 highest wave.

When this height exceeds the ground effect height the craft operates as an aircraft at a lower efficiency.

The main problems in case of operating a ground effect aircraft in choppy waters (as you noted, they are mostly operated in 'calm' seas) are twofold:

Takeoff and landing are dangerous in rough seas, due the impact loads on the hull and wings. This is the most important limitation for operating in rough seas.
Stability — The wing is already unstable, and near the ground in high lift region, it is more so; this is the reason most of the ground effect vehicles have proportionally larger tail surfaces compared to the conventional aircraft. A good example is the Soviet -90 'Orlyonko', which had tail surface nearly 50% of that of the wing.

"A-90 Orlyonok" by Kaboldy - Own work. Licensed under CC BY-SA 3.0 via Commons.

The main problem with waves (or in general, variations in height) is that the pitch stability changes with height. This results in the requirement of a large amount of control power in order to maintain trim — another reason for large tail control surfaces. Generally, the aircraft is stable in roll (the dipping wing generates more lift and the aircraft corrects itself).

Another thing to note is that the maneuverability of the ground effect aircraft is pretty limited if it's unable to fly in OGE (Out of Ground Effect). Soviet GE aircraft could fly in OGE for clearing obstacles.

References: Wing in Ground Effect Craft Review by Michael Halloran and Sean O'Meara


How are evacuation tests made as realistic as possible?

The only ‘realistic’ way of carrying out a full scale evacuation of an aircraft would be to put people in it and set it on fire. That said, FAA takes some efforts to keep the evacuation tests as realistic as possible without seriously endangering the safety of the 'passengers'. The FAA Advisory Circular 25.803-1A - Emergency Evacuation Demonstrations lays out some rules regarding this.

Only half the exits are used for evacuation by a representative mix of passengers, with some debris (luggage, pillows etc) strewn in the path.
The aircraft is to have the maximum number of passengers and flight crew, with a representative mix of age and genders with dolls for children.
Not training any of the participants in the test, i.e. both the flight crew and the participants are not trained to evacuate the (that particular) aircraft. According to the Advisory Circular,

  The flight attendants should not be trained for specific demonstration conditions, except that specific training should be given which relates to the safety of the participants prior to and during the demonstration.

The participants are clearly told what they are going to do.

  The prospective participants should be informed of the purpose of the demonstration and the expected duration of their participation.

Though the participants know 'why' they are there, they are not supposed to know 'when' demonstration is going to start.

  Neither the crew nor passengers should hear or otherwise receive any indication that the demonstration is about to begin. The first indication to participants should be the extinguishing of the normal cabin lighting.

The participants should not know about the evacuation plan beforehand.

  If safety devices or any other equipment external to the airplane could indicate to the test participants which exits are to be used in the demonstration, passengers and crew should enter the airplane through a tunnel or other means that will prevent them from seeing that indication.

The participants are more than likely paid (employees with previous knowledge of the system are not allowed), though there is no mention of any 'prize' for first getting out. The regulations simply state,

  Prospective participants should be informed of any direct benefits to them (e.g., pay, meals, etc.) and of benefits to society

The participants are prevented from interacting with outside and to recieve any information from outside the aircraft.

  ...exterior windows should be obscured from the outside to prevent both viewing of the outside conditions and any ground lighting from shining into the airplane.

There is intense debate over how 'realistic' the evacuation tests are. For example, the evacuation of British Airtours Flight 28M, a Boeing 737 took more than 5 minutes (resulting in the deaths of more than 50 people), though the aircraft had passed the test.

According to Aircraft Evacuation Testing: Research and Technology Issues, there are multiple problems with this type of testing:

There is only one data point (Full scale evacuation tests are costly; each one costs nearly $1m)
The conditions do not reflect the actual ones experienced (for example, fire, smoke etc.)
The participants know why they are there (Employees of the manufacturer are not barred, though they may not sit near the exits).
The participants do not reflect the actual demographics of the flying public, and if considered, increased the evacuation time significantly (obviously, disabled people and kids are not there in demonstration).
The participants do not experience any trauma. Of course adding smoke or fire is not an option as already around 4-5 percent people are getting hurt.

Image from Aircraft Evacuation Testing: Research and Technology Issues
September 1993 OTA-BP-SET-121 NTIS order #PB94-107620

As a result of the aforementioned BA28M accident, UK's, Cranfield Institute of Technology (CIT) carried out a number of tests which included a case where financial incentives were offered to foster competitive behavior among
test participants. The study determined that,

  the presence of a competitive element had a significant impact on egress
  rates for evacuations through the bulkheads, but did not affect the rate of evacuation through the Type III exit

Note: According to FAA, This type is a rectangular opening of not less than 20 inches wide by 36 inches high, with corner radii not greater than one-third the width of the exit, and with a step-up inside the airplane of not more than 20 inches. If the exit is located over the wing, the step-down outside the airplane may not exceed 27 inches.

The US Department of Transportation also carried out studies, which resulted in similar conclusions.

Image from Aircraft Evacuations Onto Escape Slides and Platforms I: Effects of Passenger Motivation, DOT/FAAAM-96/18

The study found that the introduction of smoke did not have much effect, but noted,

  Although this research design biased against revealing any deleterious effects of smoke on egress, previous studies using smoke had shown robust reductions in egress speed.

Giving monetary incentives to participants reduced the time required for egress.

Image from Aircraft Evacuations Onto Escape Slides and Platforms I: Effects of Passenger Motivation, DOT/FAAAM-96/18

In this study, the 'competitive' group were offered a financial bonus of $50 to be among the first 25% passengers to evacuate the arcraft. However, the passengers in the competitve trials

  ...(became) more aggressive and climbing over seats, outmaneuvering other passengers, etc. to get out quickly.

resulting in broken over seat backs, among others. I suspect participant safety is the main reason FAA doesn't offer any incentives duing demonstration.

Because of these reasons, simulations are being increasingly used in modelling evacuations which include variables like crowd behavior, state (of the person), mobility, etc.


What type of engines are used on the RNLAF KDC-10 and KC-10's?

The Dutch defence department website has the answer:

  motoren: 3 maal CF6-50C2 turbofan

Which translates to

  engines: 3 times CF6-50C2 turbofan


How to find the static stall angle of attack for a given airfoil at given Re?

Being a symmetric airfoil, the NACA 0012 does not have a particularly high maximum lift coefficient, especially at low Reynolds numbers. And yes, 300,000 is considered a low value for the Reynolds number of airfoils. On the other hand, there is no other airfoil that has been tested so much. You will find data all over the place.

Generally, the angle of attack range of interest for aeronautics is where little to no separation of the flow along the surface occurs. This is restricted to a small range around 0° (when the flow is hitting the airfoil more or less head on). Larger separation reduces lift, so right before separation first lets lift drop a little, the stall angle of attack has been reached.

180° polar for several airfoils

But stall is not the end of lift. See above for 2D wind tunnel data collected by S. Hörner in his book Fluid Dynamic Lift. These results have been collected at a higher Reynolds number when the stall angle of attack is shifted to higher values. To be honest, a lot of factors influence this. In your case, even though there is another maximum at about 45°, the stall angle of attack is between 9° and 10°. Not more.


There is a description of this route page 1-139 of "Area Planning, MTR".

The scan is not good, you may get the textual content here too.

It says terrain following activities may take place, as well as visual contours (which I assume to be navigating without radar, looking at the outdoor and searching in a catalog the same relief contour to know where you are). As you commented, taking into account the local relief:

For terrain following should be for newbies.
For visual contours navigation should be for top-guns only.

There are different routes like this, starting from nowhere and ending in the Smoky MOA. They seem to be routes avoiding nearby airfields. On the image below, I've emphasized the area without airfields, including MOAs. It looks like IR-504 is drawn along the centerline.

Based on VFRMAP

Other possible selection criteria:

Unpopulated areas (noise from low flying jets)
Low radio noise areas.
Flat terrain for UAV training.


Is there an additive that can lower the freezing point of jet fuel?

There is an additive known as a Fuel System Icing Inhibitor (FSII), it is designed to be mixed with the fuel of non-fuel heated aircraft i.e military. Mixed in at about 0.10-0.15% is optimal to reduce the formation of ice crystals, which will stop it freezing.

Source: http://www.advancepetro.com/fsii.htm

Alternatively, Jet A-1 fuel has a freezing point of -47°C, which is below your threshold and could be useful. Or if Jet A-1 is unavailable you could try Jet B which has a lower freezing point of -60°C, but is more dangerous to handle, and is less prevalent and hence unavailable at many locations.

Sources: http://webarchive.nationalarchives.gov.uk/20100814170713/http%3A//www.dstan.mod.uk/standards/defstans/91/091/00000600.pdf

http://www.csgnetwork.com/jetfuel.html


Where in the world is it possible to be a foreign air traffic controller (non-military)?

The EUROCONTROL example you give, allows controllers from all member states to work in Maastricht Upper Area Control (Netherlands) and provide ATC over Belgium, (part of) Germany, Luxembourg and the Netherlands. Many of the controllers there are not from any of these four countries so they are foreign air traffic controllers.

Also EUROCONTROL is only providing Upper Area Control above the four countries mentioned above. All member states have their own Air Traffic Control providers, some have more than one.

Within EU countries (note that not all EUROCONTROL member states are EU member states) we have freedom of labour movement. So for EU citizens there should be no official barriers to work as a foreign controller in another EU member state. Apart from the intra-EU rules, some ATC organisation within the EU are open to applications from outside the EU. For example the Dutch Air Traffic Control Organisation LVNL is open to foreign controllers. Applicants are not limited to citizens of EU countries.

ATC at airports is becoming a commercial business. The companies that you mentioned provide civil ATC at various airports around the world. Another example is ATC at London Gatwick Airport: the contract was awarded to a subsidiary of the German ATC organisation DFS.

Outside the EU I know that there are many foreign controllers work in the United Arab Emirates. They are looking for new applications at this moment as well.


What are some of the longest flights without modern navigation systems?

This list of flight endurance record on Wikipedia lists as number 3 an endurance record of 84 hours 32 minutes between May 25th and 28th 1931. It seems reasonable to assume that no modern navigation means were used in 1931.
However, the flight was mostly local, so navigation was not really required.

The all time record is from Dick Rutan and Jeanna Yeager in 1986. The Rutan Voyager had state-of-the-art navigation on board, including an Omega Navigation System and a GPS receiver. The latter was only functioning for approximately 4 hours per day, because the GPS constellation was not yet complete and many satellites were missing.

The Double Sunrise flights seem to qualify, with times in the air between 27 and 33 hours.


Is it legal to compensate a CFI for more than 8 hours of his services per day?

In my scenario, a CFI is required to be aboard a plane to satisfy
  insurance requirements.

This is the important line and you need to reference the policy for the exact wording. I happen to have some quotes from when I was shopping for an M20C about a year ago and here is the exact wording from my aircraft owner policy,

  Named Pilots and Additional Pilot Requirements

  You are to receive a minimum of 5 hours dual flight instruction in the
  make/model by a CFI who meets all the requirements of the policy and
  receive a written endorsement in your logbook from the CFI prior to
  solo; then 5 hours solo in the make/model prior to carrying
  passengers.

In this case it clearly states that the time is all flight instruction and not simply "CFI present" time if your policy is written this way then its pretty clear the FAR would be broken in your scenario. I think its safe to assume most policies are written this way although if the policy simply states CFI on board then its tough, although I agree with Ron's comment its going to be hard to explain as a CFI that you just "sat there".


What is the explanation for the different lines in the payload/range diagram for the Airbus A320?

There are two different Maximum Take Off Masses (MTOM) listed in the graph: 73.5 T and 78 T. This is only a small selection. The Airbus A320 has many variations due to modifications to fuel tanks, fuselage, engines, wings and landing gear. The following MTOMs have been certified (EASA PDF): 66 T, 67 T, 68 T, 70 T, 71.5 T, 73.5 T, 75.5 T, 77 T and 78 T.

In addition to the variation in MTOM, there are variations in the number of fuel tanks installed. The A320-100 series have either 2 or 3 tanks, while the A320-200 series can have up to 5 tanks. More fuel tanks allow an increase in range at the cost of payload. Even on short flights additional tanks will decrease the maximum payloads due to their structural weight. The brown line in the chart represents an A320 with one Additional Centre Tank (ACT) installed.

Payload includes passengers as well as cargo. Assuming an average adult weight of 88 kg (EASA PDF) including carry-on luggage, 180 passengers weigh 15840 kg. Depending on the variant of A320 you take, that leaves a couple of tonne margin for other payload such as check-in luggage or fuel to increase the range.

For more on estimating aircraft loading, see this question.


Can heated air be provided in the cabin in commercial airlines?

The fresh air vents near your head at each seat can not be adjusted for temperature individually.  Cabin temperature is controlled. Just ask a Flight Attendant to warm it up as they have a control panel to adjust cabin temperature by zone.

Most modern airliners use bleed air from the engines to power two Air Conditioning Packs which circulate cooled or heated air throughout the cabin.

Environmental control system (aircraft)

B777 Air Systems


Like every plane, the MiG-29 stores its fuel in fuel tanks ;)

On a more serious manner:

Generally speaking, there are 6 internal fuel tanks: 4 distributed around the fuselage and 1 in each wing.

Later versions (namely the SMT) have larger internal fuel capacity thanks to the enlarged spine.

The exact locations of these tanks can be seen in this cutaway (src): 63, 72, 93, 107, 187.

In addition to these, the 29 can also carry 3 (1 in the very early versions) jettisonable external fuel tanks.


What are the major causes of flameout, excluding ingestion of foreign objects?

You might be counting this as FOD, but I'm going to go with water.  That is, more rain volume than the engine can handle.  It's the reason you select continuous ignition while in moderate to heavy rain because the chance of flameout is quite high.

Next in line would be flow disturbances at very high altitude, that are normally tolerable at low altitude.  Airliners that have gotten into high altitude stall incidents can flame out one or more, especially airplanes with tail mounted engines that are in the wing's down wash.

On some airplanes the stall protection system will activate continuous ignition automatically when you are close to or at stick shaker.  Modern FADEC engines usually have an auto-relight function built in and have to demonstrate auto-relight capability for certification.

Fighters like the 262 and other first generation engines had a fuel control system that was basically a needle valve connected to the thrust lever. The pilot's eyes and brain was the real fuel control and the gauges had to be monitored carefully when making power changes.

In the early 50s hydro pneumatic fuel controllers allowed "slam acceleration" without flaming out, but engines were still sensitive to flow disruptions.  Then  variable guide vanes came along to manage the flow through the axial compressor to control blade angle of attack, and flame outs due to flow disruptions only occurred with more extreme conditions.


I'm not sure how it works in the EU as I am an American PPL student but let's ignore the small specifics and look at some general points.

Number of planes

Where I fly there are 2 flight schools; one has a fleet of about 20 planes from Grumman trainers all the way up through a Seminole. The other school has 2 planes... The obvious thing here is down time. The fact is that planes break, need routine checks and get rented by other students. A flight school with more planes (and an appropriate amount of instructors) will be able to handle these issues better. Many times I have booked a plane to find that it's in the shop and I get assigned another plane (same make and model).

Type of planes

While you cant be as picky here since sometimes geography limits you, some schools may be significantly more expensive than others. One of the nearby fields flight schools I looked at had just bought a new fleet of SR22's and were renting them at 250 USD an hour wet compared to the 100 USD an hour wet that I pay for a Piper Warrior. This can make a big difference in cost of training. Not that you are thinking this far in advance but if you do intend to one day buy a plane you may want to consider training in the type although its hard to say what kind of plane you would buy before you start flying :). If you intend on getting your instrument rating (I assume there is an EU equivalent) you will also want to make sure you are at a place that has instrument-capable planes and possibly even a precision approach system.

It also stands to reason that a place with older planes may see more down time as the planes may need more service but most old planes that I have flown are well kept. Here in the US trainer planes need to be inspected every 100 hours so they are out somewhat frequently for that already.

Number of instructors

Here in the US many instructors are doing so to get enough hours for their ATP. With that in mind instructors are subject to leave at any time if they make their hours and find a commercial job. Bigger schools will be able to reassign you to another instructor or may have better luck hiring a new instructor to fill the gap.

Type of airport

Again sometimes you can't be picky here because of geography but training at a towered airport as apposed to an uncontrolled field can help you hone in your radio work from day one. A bigger slightly more busy airport may also give you real experience with things like wake turbulence avoidance. Most larger airports also tend to have 2 runways which can help you on those windy days (depending on direction and such). They also tend to have better services like plowing, precision approaches, fuel (not all airports have gas!), pre-heats that don't take 20 minutes to show up etc. This can also be a but of a curse sometimes as larger airports are subject to traffic and you may find your self sitting on the runway waiting to take off on a nice day.

Cost

This can be a big factor for some people. Some are lucky enough to have the money to fly where its easiest for them (close to home or work) etc., while others don't have this luxury and must fly where its the cheapest. Here in the US a cheap school will still get you the same PPL that a super expensive place with a brand new SR22 will. So if your goal is simply to fly and cost is a serious factor there is nothing wrong with going with the cheaper option (which may involve driving a bit farther) as long as you factor in the potential down time of the planes or difficulty of booking them.


Why is the manufacturing process of an aircraft mostly manual?

Although robots have taken over many jobs in the process of manufacturing things like cars, airliners are much larger and more complex. In some ways it has more in common with constructing a building than assembling a vehicle. There is a much larger variety of tasks to be performed over a much larger area.

That being said, many parts of the manufacturing process are completed by robots. For example, Gemcor makes machines that automatically drill aircraft wings and fasten them with rivets and bolts.

Robots are also used in manufacturing large composites. You'll notice how massive these machines are, and they are only completing one task on one component. They are very good at tasks that require one or more of force, repetition, and accuracy.

However, so much of the process is not economical to be done with robots. A robot specializes in one task or one type of task, while humans can do many different tasks. Many tasks involve working in tight spaces, which humans can do better than a large robot. Tasks like installing wires require dexterity as well, which humans are better at.


How did the AAIB assist in locating MH370?

The following statement has just been released today by the Prime Minister of Malaysia, in relation to the AAIB:

This evening I was briefed by representatives from the UK Air Accidents Investigation Branch (AAIB). They informed me that Inmarsat, the UK company that provided the satellite data which indicated the northern and southern corridors, has been performing further calculations on the data. Using a type of analysis never before used in an investigation of this sort, they have been able to shed more light on MH370's flight path.
Based on their new analysis, Inmarsat and the AAIB have concluded that MH370 flew along the southern corridor, and that its last position was in the middle of the Indian Ocean, west of Perth.
This is a remote location, far from any possible landing sites. It is therefore with deep sadness and regret that I must inform you that, according to this new data, flight MH370 ended in the southern Indian Ocean.
We will be holding a press conference tomorrow with further details. In the meantime, we wanted to inform you of this new development at the earliest opportunity. We share this information out of a commitment to openness and respect for the families, two principles which have guided this investigation.
Malaysia Airlines have already spoken to the families of the passengers and crew to inform them of this development. For them, the past few weeks have been heartbreaking; I know this news must be harder still. I urge the media to respect their privacy, and to allow them the space they need at this difficult time.

It's not a "new technology" per se, but a new form of analysis. You might have heard recently that the aircraft responded to hourly "pings" from a satellite:

British satellite company Inmarsat immediately began doing calculations based on a series of hourly "pings," as the plane and one of the company's satellites tried to communicate with each other.
Triangulating those pings seems to have given Inmarsat a pretty good idea of where the plane went, along one of two routes, to the north and to the south.

Here is some further information:

About three hours after Flight MH370 went missing, Inmarsat, a British-based satellite company, began tracking the Boeing 777 through an on-board data system called Aero Classic. Every hour, Inmarsat's satellites would try to communicate with the aircraft, pinging it with a computerized question asking, in effect, "Are you there?"
For several hours, Flight MH370 responded "Yes, I am," notifying engineers on the ground with a so-called handshake that the plane was still powered up.
Using that series of pings, Inmarsat engineers and other analysts were able to piece together two broad, arcing regions where the plane could have been located when it last communicated with the satellite.
"Our engineers looked at the time between the handshakes, and they realized that the object wasn't stationary under a satellite but moving away from it," Christopher McLaughlin, senior vice president of Inmarsat, said Thursday. "Over time, the engineers here recognized that there were a number of data points and that it had flown for several hours. We didn’t know if it was on the northern or southern corridor."

More information on how Inmarsat determined MH370 flew along the Southern corridor specifically, will likely be released tomorrow at the press conference (as mentioned in Najib Razak's statement), which I gather is the information you're looking for.


How does the U.S. Overflight Fee system work?

Correct. Some countries charge overflight fees regardless of whether you land or not. In the US, overflight fees are charged per 100 nm. You can find the exact fees for 2017, 2018 and 2019 here. The fees can be paid online, and the FAA is pretty modern when it comes to this; it accepts ACH transfers from a US bank account, Amazon account, Dwolla account, PayPal and Debit or credit card.
The aircraft has to identify itself. The flight plan tells the FAA who you are. They look you up in the registry of the country in which your aircraft appears and send you the bill.
Unpaid fees accrue interest, and can result in the aircraft being denied entry into US airspace or impounded if it does happen to land at a US airport. The FAA can also put liens on the aircraft in the country of registration, which would have to be paid before the aircraft registration changes hands.


What is the purpose of the Dash 8’s “TOUCHED RUNWAY” warning light?

The light is a tail-strike indicator.

  Touched Runway system

  The  Touched  Runway  system  provides  a  warning  light  in  the  flight  compartment.  It  illuminates when the aft fuselage makes hard contact with the runway on take off or landing. The system consists of a frangible1  switch located at the bottom of the aft fuselage, activating the warning light. The system is powered from the 28 Volt DC right main bus. Once activated, the frangible switch can not be reset but must be replaced by maintenance personnel. Source: Smart Cockpit.

1 frangible
/ˈfran(d)ʒɪb(ə)l/,
adjective

able to be broken into fragments; brittle or fragile.
"the frangible skull of an infant"
denoting ammunition designed to disintegrate into very small particles on impact.
    "frangible bullets"

Figure 1. Source: ATSB.au.

Figure 2. Source: ATSB.au.

Links:

Tail strikes during landing involving Bombardier DHC 8 402, VH-QOT and VH-QOS.
AAIB Bulletin: 10/2017 G-ECOJ EW/G2017/01/03.


You assume that airlines always fly the published SID or STAR. That's not true though. SIDs and STARS are used in procedural control to separate arriving and departing flights. When you have radar, then you don't necessarily need the procedures to do that.

When a flight is cleared for takeoff they are assigned a SID that is relevant to its destination. After takeoff and when the flight is handed off to approach (1) controller, the controller will give a vector (heading) to the flight or direct to a point on the TMA boundary. If for any reason (see below) they intend to keep the flight on the SID the controller says proceed as cleared(2) on first contact.

For approach, the flight is assigned a STAR and when it reaches the TMA boundary, the approach controller will give them a vector and the flight will deviate from the assigned STAR. See this video from NATS  and watch the arrivals to Gatwick. Compare the trajectories to what you see in the instrument procedure maps from their website. They don't seem to follow a route looking like that

source: UK AIP chart AD 2-EGKK-7-5

They seem to go direct to the holding stacks. And after exiting holding they don't seem to follow any of these routes

source: UK AIP chart AD 2-EGKK-7-12

Now when will a flight actually do the SID or STAR you will ask. There are several cases like for example TMAs without radar service. Normally the control is procedural in that case and that includes flying the assigned SID or STAR. Another case is during unusual circumstances like for example equipment failure (radar, communications etc) that will make radar vectoring harder or even impossible.

It's worth noting that it's common for pilots to ask for shortcuts if that can be done legally. For example if the weather conditions are VMC an arriving flight might request a visual approach. In that case IFR is canceled and the pilot will deviate from the STAR or IAP.

During takeoff, a pilot might request direct to an en-route point and thus exit the SID. If the current controller cannot grant it (let's say no radar contact), they will ask the next controller (en-route controller) if they can grant it. If yes (the en-route radar has the flight) then the flight is handed over to en-route and they are granted the direct, exiting the SID. That might not always be the case. If for example en-route control has radar contact, but because of heavy military activity the direct cannot be given safely, then the flight stays on the SID until the end.

Notes

Links to pdfs unfortunately don't work; you need to open them manually from NATS AIS page, linked in main answer.

(1) Or departure, sometimes it's the same controller.

(2) This phraseology is used in Greece (and I hope I remember it correctly). Other jurisdictions might use something slightly different.


Why is it called "STBY RUD" on a Boeing 737?

According to the Boeing 737 Flight Crew Operation Manual, the "Standby Hydraulic System" only powers the following:

thrust reversers
rudder
leading edge flaps and slats (extend only)
standby yaw damper

It does not power, for example, brakes, ailerons, spoilers and the landing gear.

I speculate that the word is chosen to remind pilots that the system powers the rudder but not other primary flight controls.


How often is the name painted on fighters?

I cannot answer for the USAF, but Navy and Marine Corps squadrons have also done this for years.  In addition to the pilot, if there is more than one seat the Weapon System Officers name(s) will also be painted, in addition to the Plane Captain.  It is an honor to have your name on a plane, and it is done for morale reasons.  It does not mean that that airplane is assigned to you alone.
Names are painted based on seniority in the squadron.  Typically there are more crews in a squadron than airplanes, so the junior most pilots will have to wait for some time to have their name on a plane.  It is a minor rite of passage when it happens.
For example, in the EA-6B squadrons I served in there were 4 airplanes, and typically 6 crews assigned.  The senior 4 pilots got their names painted, and if memory serves me correctly, the Naval Flight Officers, (NFOs, or WSOs...) who were assigned to their crews were also painted on the same plane.  So, while a junior pilot might need to wait a year or two, a brand new NFO assigned to the Commanding Officer's crew might get on right away.
They are painted on with a stencil whenever a change is called for.  It is low priority in the maintenance scheme of things, so when a senior pilot transfers out and someone moves up the rung it might take several weeks before the plane is moved into the hangar for some other maintenance interval, and the name is repainted then.


Who decided that the Boeing 737 MAX planes that were airborne when the grounding was issued cannot enter and land in EU air space?

The operator's airworthiness department interprets the AD and informs the operations department and senior management.  Ops decide how to deal with airborne aircraft.

The EASA AD actually had more generous continued flight provisions than the FAA issued AD.  It was in no way intended to prevent aircraft in flight from landing.  Airworthiness would immediately talk to operations.  Operations would decide what to do, though in most cases a few phone calls would be made to senior management.  If the aircraft can't make it back to a 'home' port, that pretty much dictates what is going to happen next (continue to destination).  In the subject case, a number of aircraft were airborne and capable of returning to a home port.  So you need to figure out what to do next - continue flying to your EU destination and get your passengers there with minimum inconvenience (with possible adverse publicity for not discontinuing the flight as soon as possible), or simply get the aircraft back to base so that you don't have it stuck somewhere needing maintenance (and reading between the lines, Ops and Airworthiness would be concerned that the recovery might become more complicated than the 3 flight cycle limit ferry suggests).  So better to get your pax down ASAP, at a port where you can easily carry out whatever rectification is needed, and importantly too, also one where you have more aircraft available to get your passengers to their destination without having to do positioning flights.

In some cases, such as TUI, they elected to divert the aircraft to the nearest suitable port, regardless of destination or home port convenience.


Flying VFR in uncontrolled airspace, what to do if one spots an apparently out-of-control fire on the ground?

This has happened several times and each time I was able to reach a local approach facility.  Prior to GPS, I would circle above the event, and approach would get a pretty good fix.  One time it was a propane facility near the uncontrolled airport I was flying out of at night.  Shortly there after, when the flames shot above 4500 feet, the tower saw it form 20 miles away, visually.

One of the more interesting events was one early spring, when I was crossing the Finger Lakes in New York, and saw two snowmobiles go through the thin ice.  I hung around for the recovery, and everyone was pulled out of the water alive.  In that instance, (Rochester) approach kept asking for updates, as they were talking with the fire departments, who were trying to find the best ice for their approach to the snowmobilers.

In my experience, I have always been able to reach approach.  However if approach was not available, enroute or FSS, and as a last resort, local unicoms.

When flying for the state conservation department, we did radio in fires, as part of the job expectation.

For those looking for more guidance, might I suggest something like:

Cessna345: Approach, Cessna 12345, 20 miles south, near Geneseo VOR, with two snowmobiles through the ice on the lake, 5 miles southeast of the VOR.  Three souls observed in the water.

Apch: Cessna 345, squawk 4311, ident, say altitude.  How long ago did this happen.

Cessna345: About 2 minutes prior to my call up. 1500.

Apch: Any other snowmobilers in the area?

Cessna345: No, not at the north end of the lake.

Apch: Fire is being dispatched from both sides of the lake, would you say the swimmers are closer to the east or west shore.

Cessna345: East shore, advise fire that I am circling above the swimmers, with landing lights on.

and so on.

Addendum: The question asked about uncontrolled airspace, and while there may be uncontrolled airspace even in areas of radar and ATC coverage, it is useful to discuss what to do when ATC coverage is more sparse.  The objective is to communicate to authorities so that fire services can be dispatched to control the fire, and alert people who might be in harms way.  My suggestion, as a CFI and as someone who has flown the northeast corridor as well as rather desolate portions of the earth, is to establish communication with anyone on the ground as soon as practical.  If you can reach any FSS or ATC facility, I would contact them first.  If unable, and if nearby (considering your altitude) I would try airports with unicom/multicom frequencies listed.  You might alter your flight to get you closer to civilization and potential contact points. In Northern Canada, as an example, there are many well equipped airports which are not charted, but support mining operations. I carried a list of their frequencies shared with me by regional pilots.  Barring that, I would make calls on 121.5.  There may not be any facilities around which are in range for 121.5, but there are likely airlines and military flights which monitor 121.5, particularly in cruise. It is not uncommon to use other aircraft to relay information, and short concise messages help.  If one has HF or a SATphone, then the radio game is different.  In extremely sparse areas, a fire may only be of advisory interest, so do not expose yourself to increased risk to report it.


What is the reason for this engine oil service procedure on a Bombardier CRJ?

The Aircraft Flight Manual or Flight Crew Operating Manual will specify the timeframe during which engine oil may be checked after engine shutdown. For the CF34-3B engine on a Challenger 605, checking must be done between 15 minutes and 2 hours following shutdown.
If done outside of this window, the engine must be dry-motored (cranked without introducing fuel) for at least 30 seconds.
Otherwise the oil level may (incorrectly) show too-low (the oil tank is not at the bottom of the engine), which could lead to overfilling. Overfilling is said to be worse for jet engines than operating them with slightly too-low oil levels.


What is the "8900" that the FAA uses for guidance?

The Flight Standards Information Management System, created by FAA Order 8900.1, is the source of all information relating to aviation safety inspector job tasks.  It's about 8,000 pages worth of (non-regulatory) guidance and policy helping FAA Inspectors to do their job properly.

It's an electronic-only document, which can be found at fsims.faa.gov, or by visiting the FAA homepage and entering "8900" in the search box at the top right.

There's all kinds of good stuff in there, such as:

How do I give a practical test for a CFI applicant with a sport pilot rating?
How do I perform field approval of a major repair or alteration?
How do I do a ramp inspection?

And lots more!

FSIMS is open to the general public - if you want to know what an inspector does day in and day out (or what to expect when you meet one), FSIMS is the one-stop-shopping location for the answers to all your questions.


Can a someone with just a PPL log PIC time on a non-transport commercial flight?

Yes, you can log PIC in an aircraft category and class that you are certified to fly. You can log that time during which you are the sole manipulator of the controls. This is the case even if another crew member (the commercial pilot) is the acting PIC.

See 14 CFR 61.51 (e) for this and other situations allowing logging of PIC.

Following is the relevant section of 61.51 (e):

  (e) Logging pilot-in-command flight time. (1) A sport, recreational,
  private, commercial, or airline transport pilot may log pilot in
  command flight time for flights-

  (i) When the pilot is the sole manipulator of the controls of an
  aircraft for which the pilot is rated, or has sport pilot privileges
  for that category and class of aircraft, if the aircraft class rating
  is appropriate;


What determines the maximum altitude a plane can reach?

The higher you get, the lower the density of the air becomes. This lower density results in a lower lift being generated for the same airspeed and angle of attack. Effectively, the higher you fly the higher your minimum speed becomes. So while climbing, your speed needs to increase to compensate for the lower air density. As long a you can fly faster, the lower density at altitude can be compensated for.

Basically there are two things that limit your maximum speed: thrust and speed of sound and with that your maximum altitude.

First is thrust; the higher you get, the lower the thrust your engines deliver. You might note that drag goes down with the air density as well but since you are flying faster and faster during the climb the drag doesn't decrease at all. If your maximum altitude is limited by thrust then at some point during the climb the thrust and drag are getting close to equal and that is where the climb stops. When you can no longer climb with more than 100ft per minute (for propeller aircraft) or 500ft per minute (for jet / turbofan aircraft) you have reached your service ceiling. If the aircraft maximum altitude is determined by thrust, the absolute ceiling will take very long to reach.

At high altitudes air breathing engines will get difficulties eventually. Due to the lower air density the mass flow through the engine is reduced up to a point where it causes a flame out.

The other limitation is the speed of sound, at least for subsonic aircraft. In the process of generating lift, air flowing over the top of the wing is accelerated. At one point, when the aircraft is still flying below the speed of sound, shock waves will start to form over the wing. This results in increase of drag and reduces the lift. So provided you have enough engine power at your disposal you can climb to an altitude where your minimum speed is also your maximum speed. This is called the coffin corner. In the coffin corner:

if you fly any faster, you will exceed the maximum Mach number ($M_{mo}$) of your aircraft, resulting in high speed buffet, vibrations and possible loss of control.
if you fly any slower, the maximum lift that the wing can provide will be insufficient to maintain altitude. Descent or the aircraft will stall.
if you fly any higher and you will be too fast and too slow at the same time.
if you turn, you increase the wing loading, thereby increasing the minimum speed needed to create the required lift. Also the outer wing will easily exceed the maximum speed while at the same time the inner wing is below stall speed. This can quickly develop into a spin.

Since accurate knowledge of engine performance, drag and wing characteristics of the aircraft is needed, there is not a simple formula to derive the maximum altitude for an aircraft.

Apart from the aircraft performance related limitations above there is a certified maximum operating altitude for the pressurized cabin. This takes into account the structural properties of the hull (pressure difference between inside and outside) and the achievable emergency descent rate in case of a depressurization event.


Why do double-ended ILS runway share the same frequency from both sides?

Listen to the identifier... That will tell you if you have the 10R I-MRY or the 28L I-MTB ils.  Some runways use the same frequency like this, while others use different frequencies for opposite direction ILS's.  The identifier will always be unique, though.

The 10R transmitter doesn't operate at the same time as the 28L transmitter. One transmits "this" ils beam in "this" direction using "this" ident on whatever frequency; the other transmits a different ils beam in a different direction using a different ident; the fact that it is or is not the same frequency is incidental.

Usually, the two reciprocal ILS's to the same length of pavement use the same frequency, with one switched off when the other is switched on.  MRY in the OP is a good example of this, and most other airports I looked at have the same behavior, but this is not universal.  Reno, NV -- KRNO -- is an example where the opposite ILS's are not on the same frequency: 16R ils is 110.9, but 34L ils is 109.9. Same pavement, different frequencies.  Also, Detroit, MI -- KDTW -- appears to have two full ILS's set up for runway 4R/22L, with one pair on 111.75, and the other on 111.95.

One other note: the various flight simulator programs may or may not accurately model this behavior.  Some may simply have every ILS "on" at the same time, so if you're west of "this" airport, you'll receive the ILS for landing east, and vice versa.  Works well for a flight simulator program, but that's not how the real world works.  It takes a call to tower to have the one ILS turned off and the other turned on, and it isn't something they prefer to do repeatedly or on short notice.  In the sim, it's convenient to fly approaches back & forth to 16C then 34C then 16C and so on, but even if traffic permitted, in the real world they'd probably prefer you flew your ILS's to one runway, and use something that doesn't need the ILS or the LOC when landing in the opposite direction.


Where are the bags generally stored on an airliner?

In smaller aircraft, the baggage is put directly inside the cargo hold.

Source: jacksonville.com

In case of larger aircraft, the baggage is put inside the conformal cargo container or the unit load device, which is then placed inside the cargo hold.

Source: roger-wilco.net

Source: supath.net


Is it allowed to fly a right traffic pattern when a left traffic pattern is published (IFR)?

Yes, it is legal to circle north under IFR using "right" hand traffic and land on Runway 25.

"Left traffic" refers to VFR traffic. Traffic patterns are generally flown at 1000' AGL. IFR aircraft don't fly traffic patterns unless they cancel IFR or are doing a visual approach under direction of an active control tower.

An IFR aircraft on a circling approach can maneuver at any altitude (above the published minimum altitude), and in any direction, in order to align itself with the landing runway. .

When you are issued an IFR clearance at an uncontrolled airport, the IFR airspace around the airport belongs to the IFR aircraft. I think FAR 91.126 (a) General. "Unless otherwise authorized or required" would supersede the left traffic requirement.

In this case it is mandatory to circle right because Circling south of runways 7/25 is not authorized. ("NA")

If the weather was above VFR limits, and there was also a VFR aircraft in the area, they would have to fly a left traffic pattern and communicate to avoid conflicts.


Was any Russian design feature incorporated in modern US fighters jets or vice-versa?

Three things come to mind:

Geometric shaping for stealth is based on the theoretical work of Petr Ufimtsev, a Russian mathematician who explained how to calculate the reflection of radio waves from the 1960s on.
The sight-controlled missile targeting which appeared in the MiG-29 in the 1980s. In combination with the wide off-boresight capabilities of the aircraft's radar and the missiles, it allowed to get a lock on aircraft flying actually behind it. When US F-16 met ex-GDR MiGs in exercises in the early 1990s, they were shocked to find how much superior the Russian design was and soon copied it.
The rotating collars which were used on the Yak-141 to deflect the engine exhaust straight down for vertical take-off have been used in the VTOL version of the F-35. Lockheed-Martin co-operated with Yakowlev in the early Nineties to learn how the Russian airplane works.

From a historical perspective you can add the Russian (actually, Georgian) aircraft designer Alexander Kartveli, who headed engineering at Republic, and the influence of Georgia-born Alexander de Serversky (actually of Russian descent) who propagated strategic bombing to win future wars, even though this concerns bombers, not fighters.


What is the difference between a loss of control and an upset?

Aircraft upset

   is a dangerous condition in aircraft operations in
  which the flight attitude or airspeed of an aircraft is outside the
  normal bounds of operation for which it is designed. This may result
  in the loss of control (LOC) of the aircraft, and sometimes the total
  loss of the aircraft itself.

Loss of control

   is the unintended departure of
  an aircraft from controlled flight, and is a significant factor in
  several aviation accidents worldwide and the leading cause of jet
  fatalities worldwide. Loss of control may be the result of
  mechanical failure, external disturbances, aircraft upset conditions,
  or inappropriate crew actions or responses.

TL;DR:

Upset occurs when attitude and/or airspeed are outside of the boundaries where the aircraft is controllable.
Upset is one of many possible causes for loss of control.


According to LOCAL FLYING OPERATING INSTRUCTION / 440 AIRLIFT WING INSTRUCTION 11-250 / OPR 440 OSS/OSA:

  5.7.4. ARRIVAL PROCEDURES:
  5.7.4.1. DESCENTS:
  5.7.4.1.1. TACTICAL (PENETRATION) DESCENT (Overhead, Downwind, Beam, etc): High rate (unrestricted) visual descent profile designed to transition an aircraft from a high-level altitude structure to a low-level altitude structure putting the aircraft in a safe position to execute a tactical approach.
  ...
  5.7.4.1.3. TACTICAL (PENETRATION) DESCENT ASSAULT – High rate (unrestricted) visual descent profile designed to transition an aircraft from a high-level altitude structure to a low-level altitude structure putting the aircraft in a safe position to execute a tactical approach to an assault landing zone. Note: A separate penetration descent profile may also be flown to Mackall AAF (HFF), see Pope Aircrew In-flight guide for procedures.
  5.7.4.1.3.1. Arrival Procedures:
  5.7.4.1.3.1.1. When sequenced, commence penetration descent to a tactical approach, ARA, or normal pattern. Request desired approach as early as possible upon switching to Pope Tower.
  5.7.4.1.3.1.2. Remain at or above 2500’ MSL until within 5 NM of Pope. Do not descend below 720’ MSL until given clearance to land from Pope Tower.

See also fooot's answer to another question, where he describes a tactical descent as an extremely steep descent, and a tactical approach as an extremely steep approach.

According to other sources, the technique in question might also be called (depending on the exact landing circumstances) an Assault Landing, a Sarajevo Approach or even a Khe Sanh Approach or an Overhead Approach.


Are there benefits to opening a flight plan if I'm flying over populated areas?

According to the AIM section 5-1-4, the main reason is search and rescue:

  b. It is strongly recommended that a flight plan (for a VFR flight) be
  filed with an FAA FSS. This will ensure that you receive VFR Search
  and Rescue Protection.

So the question becomes, does search and rescue have value in populated areas? I would say that - excluding large cities - populated areas are actually not very densely populated at all (relatively speaking), and there is a very good chance that no one will see your aircraft come down or even react if they do. You might be flying at night, or no one may be looking in the right direction, or they may assume you're landing at a private strip or doing cropdusting or whatever.

And even when an aircraft is known to be down in a specific area, it's often very hard to find it - especially if you land in trees - so anything you can do to narrow down the search area is important. An AOPA safety video (I forget which one) mentioned an incident where a helicopter went down less than a mile from a runway threshold at a class B airport and it still took 24 hours to locate it (the details may be different, but you get the idea).


Can a commercial pilot transport friends for free?

According to this interpretation that seems to match your scenario very closely, as long as you're also attending the event then a single trip is fine but multiple trips are not. And you would be acting as a private pilot, not a commercial pilot.

The interpretation was about an ATP who ferried fellow club members to an event (in nine flights!) and did receive money to cover costs, but the main points would apply to a CPL in your scenario too. In summary:

Flight time is compensation, therefore you're being compensated for the flights even if no money changes hands (the ATP argued that flight time in a C172 was worthless to him, but the FAA said they don't analyze individual cases)
Acting as a private pilot you can receive compensation only if a "bona fide common purpose" exists

If you aren't attending the event yourself, there's no common purpose
If you are attending the event, only the first flights there and back have a common purpose; subsequent flights to bring more people to the event do not

Acting as a commercial pilot you can receive compensation for transporting people only if you have an air carrier certificate (per 14 CFR 119.1)

You didn't give many details about your scenario, but if you're attending the event yourself then you should be fine for one flight each way under your private privileges. Any more than that and there's no common purpose.

Of course, the caveat here is that every situation is different and perhaps there's something about your case that would result in a different FAA interpretation. However, the basic points about compensation and common purpose are very consistent across interpretations.

(Apologies for not quoting the interpretation directly, but the FAA seems determined to make it as difficult as possible to copy and paste from their documents.)


How is a propeller diameter for given application determined?

Let's start over with the basics.

In any application, the prop tips have to be maintained subsonic or else propulsion efficiency will suffer and noise generation will become extreme. Therefore, for any given prop diameter, there is a do-not-exceed RPM value associated with the sonic limit: big props have to turn slower, smaller ones can turn faster.

(Prop diameters are also limited by ground clearance considerations but for small planes like a Cessna 172 or a Cherokee 160, the need to keep the prop tips out of the grass can be accomodated readily.)

Next you have to match the prop with the best power operating point of the engine turning it. For 4-stroke gasoline engines of typical design this will be around 2500 RPM at which the engine is producing roughly a half horsepower per cubic inch of displacement. You then pick the maximum allowable prop diameter to keep the tips subsonic at 2500 RPM.

Next you assume the minimum number of blades for a start (2) and select the pitch angle at that diameter which will absorb the full output of the engine running at 2500 RPM. If two blades will not load the engine enough to hold it at 2500RPM at full throttle, then you add another blade and repeat the process.

For engines of less than about 180HP, the right answer is a two-bladed propeller of fixed pitch. For engines bigger than that, the right answer is generally a two- or three-bladed propeller with variable pitch.

One way to beat the sonic limit while getting more power out of the engine is to gear the engine down so it is spinning faster, and thereby generating more power, while still maintaining the prop tips subsonic. This also lets you further reduce the prop tip speed and go for a larger diameter prop if you have the ground clearance available, which will generally be more aerodynamically efficient than a smaller one- but running the engine faster shortens its service life and the cost to rebuild a geared engine has to include the cost to rebuild the gearbox itself.

For light aircraft in the homebuilt class or for ultralights, a less-expensive alternative to the geared engine is one with a rubber-belt reduction drive. This lets you use lighter and simpler 2-stroke engines which have a best power point of around 4500 RPM and still maintain the prop tips subsonic.


How can I calculate the fuel required for a specific route and aircraft?

If you just want something simple, just look up the average fuel consumption for the aircraft type (in gallons per hour), and multiply that by the duration of the flight. Although airlines have more sophisticated tools to plan refuelling, this is how GA pilots estimate how much fuel there should be in the tank.

Official fuel consumption figures can be hard to get hold of because the Pilots' Operating Handbook and other documentation for the aircraft might not be publicly available, but it's easy to find out rough figures from web forums populated by pilots of that type.

If you are interested in something more complex (and accurate), see How can I calculate the fuel consumption of an Airbus 320-200 at various loads?


How to take into account wind in aerodynamic forces balance?

Additional response to edited question: object is dropped with an initial groundspeed of zero: the only forces present as object falls are gravity and aerodynamic drag.  Drag is a function of airspeed, which has a vertical component as well as a horizontal component.  If you use the airmass reference frame, the ONLY significance of wind is that 1) the initial condition is that airspeed equals wind speed, and 2) during the time the object is falling there will be some horizontal translation between the airmass reference frame and the ground reference frame, which will affect the final answer when converted back to the ground reference frame.  See notes below, and links at end, about not being able to solve for vertical and horizontal accelerations independently of each other.

Read on for more (some content was originally aimed at a broader version of the question)  :

Cutting to the chase, is the object being dropped from a freely drifting balloon, or from a tower, or from an airplane?  I.e. is the horizontal airspeed initially zero, or not?  Dropping from an airplane is more like dropping from a tower than dropping from a freely drifting balloon, because the initial horizontal component of airspeed is not zero.

Once an object has accelerated to freely move with the wind, the horizontal component of airspeed is zero, so the wind exerts no force on the object. This makes calculations easier.  In theory, if the initial horizontal component of airspeed is non-zero, it will take a infinite amount of time for the horizontal component of airspeed to fall all the way to zero, just as it takes an infinite amount of time to fully achieve the vertical terminal velocity.  In practice, after a few tens of seconds the horizontal airspeed will probably be very close to zero.

If the object is initially released with zero groundspeed, then the horizontal component of the airspeed vector is initially not zero, but rather is equal to the wind speed.   It turns out that this has an effect on the object's vertical acceleration as well as the object's horizontal acceleration, even if the body is a perfect sphere!  (See links below for more.)

If the object is dropped from an airplane, wind or no wind, the situation is essentially the same as if the object is dropped from a tower in wind.  The key point is that the horizontal component of airspeed is not zero at the instant of release.

If horizontal as well as vertical airspeed, force, and acceleration components are present at the instant of release, then you need to take care to properly consider the true magnitude and direction of the net aerodynamic force acting on the object.  You need to write your equations in terms of the airspeed vector, which also is equal to the ground speed vector (including the vertical component) plus the wind speed vector.  You can't treat drag due to wind speed, drag due to horizontal ground speed, and drag due to vertical falling speed as independent entities, because drag is dependent on airspeed squared, and all these components of motion contribute to airspeed.

Ultimately it's up to you whether you want to work in terms of the airmass reference frame (which moves with the wind) or the ground reference frame, so long as your equations appropriately deal with the x, y, and z components of the airspeed vector.  It will generally be much easier to work in terms of the airmass reference frame, and view the ground as moving carpet down below, like one of those airport people-mover beltways.  Just bear in mind that IF the object is released with zero groundspeed, then the initial condition is that the horizontal airspeed equals the wind speed.  IF the object is dropped from a freely drifting balloon, then the initial condition is that airspeed is zero.  IF the object is dropped from an airplane, then the initial condition is that the dropped object's airspeed equals the airplane's airspeed.  Regardless of which is true, once the appropriate initial condition is set, forget about the wind, except for checking at the end to see how much the ground moved relative to the airmass reference frame, during the time of fall.

In other words, if the object is released from an aircraft with a known airspeed vector, and the airmass (wind field) is uniform, then you can ignore the wind while you do your calculations in terms of airspeed, and then you can add on the "drift" relative to the ground due to the translation of the airmass reference frame relative to the ground during the time of fall.

It appears from your question that you hoped to be able to compute horizontal acceleration components independent of vertical acceleration components.  In any case where the object's initial horizontal airspeed is not zero, that's not going to work.  Just as the horizontal airspeed at any instant affects the rate of change of vertical airspeed, so too does the vertical airspeed at any instant affect the rate of change of horizontal airspeed.  See links below for more.

On the hand, if you are just dropping objects from a freely drifting balloon in a uniform wind field, then you can ignore most of this answer.  In that case, horizontal airspeed, force and acceleration are zero.

These links should be of some use to you: see all associated links as well:

https://physics.stackexchange.com/questions/176513/calculating-wind-force-and-drag-force-on-a-falling-object/176515#176515

https://physics.stackexchange.com/questions/491600/flight-time-of-spherical-bullet-fired-horizontally-versus-dropped-vertically-e/491771#491771


Are there any pressurized piston-engine aircraft?

The first pressurized aircraft were piston powered, beginning as early as 1921 with a modified Airco DH.9A containing a pressurized enclosure for the pilot.  Throughout the 20s and 30s, pressurization systems developed in reciprocating powered aircraft with benchmarks like the Lockheed XC-35 being the first pressurized aircraft using bleed air from its super chargers to pressurize the cabin and the Boeing 307, the first pressurized airliner.  World War II saw plenty of pressurized pistons like versions of the BF-109 and the Ju-86, as well as the Boeing B-29.

Postwar airliners were also pressurized.  The Boeing 377, the Douglas DC-6 and the Lockheed Constellation were all good examples of this.  With the introduction of jets, these quietly faded into obscurity.

There are a few pressurized piston single and twins in operation today, though manufacturers did not make very many.

Probably the most successful pressurized single is the Piper PA-46 Malibu series introduced in the 1980s and still in production today, in both the form of the reciprocating PA-46-350 Mirage and the turbine powered PA-46-500 and -600 Meridian.

In the late 70s and early 80s a number of manufacturers attempted to enter the pressurized entry cabin class single engine market.  Cessna offered a Pressurized version of the C-210 Turbo Centurion called the P210 which is no longer produced but still popular with GA pilots today.  Mooney, after finding marginal success with its pressurized M22 Mustang from the 1960s, decided to produce a pressurized six seat cabin class airplane called the Mooney 301.  It was stillborn due to financial pressures from Mooney's new owners but the best technology from it was cannibalized in a ill-fated partnership with Aerospatiale (now Daher Socata) in Tarbes France to produce a single engine turbine airplane which eventually became the TBM-700/-850/-9XX (TBM stands for Tarbes Mooney).

Even a few homebuilt piston singles have been pressurized.  Lancair's IV-P, ES-P, and piston versions of their Evolution are all pressurized and capable of nearly 300 KTAS at FL250.

More piston twins have been pressurized as well.  Cessna produced a pressurized version of the C-337 Skymaster called the P337G, as well as the 340, 414 and 421.  Piper produced the PA-31 Navajo.  Beech produced the BE-60 Duke as well as a variant of the Queen Air called the B88. Rockwell produced the Aero Commander series.


Is it possible to take PPL lessons in different locations and countries?

As a practical matter, it will probably be too much hassle to get signed up with new flight schools in each city/country you visit for only one or two lessons, especially in the US where you need certain classes of visa (no VWP), permission from DHS, etc.

Also, FAA and ICAO/EASA rules can be pretty different. If you know one well, you can fairly easily learn the other (or just muddle along without anyone noticing), but I wouldn't want to mix the two during primary training. Learning one set of rules is hard enough.

The only case where this might make sense is if you'll be visiting the same city repeatedly and can get the same instructor every time, which eliminates most of the overhead. I did this (both cities in US), and my home instructor would give me a specific list of things to work on for each trip, and when I came back, I'd show what I'd learned and we'd move on to the next thing. After I soloed at home, I did a mock checkride for my other instructor and he soloed me too. Having two instructors did cost me more in total flight time, but it minimized calendar time because instead of losing proficiency by having long gaps between lessons, I was gaining proficiency by flying regularly. It also helped that the two had different teaching styles, so if one wasn't getting through to me, the other would. Still, I wouldn't recommend it if there's any other option


Theoretically? Yes.
Practically? No.

In order to construct an alternative Flight Data Recorder narrative good enough to fool investigators you would have to acquire a flight data recorder to feed the data to (this is the easy part). You would then need to feed the appropriate parameters to the flight data recorder to fill its memory (modern recorders can hold over 10 hours of data - this could encompass several flights that would have to be believably reconstructed - speeds and altitudes matching radar track data for example).
A flight simulator could probably be rigged up to supply the data to the recorder, so the primary difficulty here would be matching your forgery to other data sources like RADAR tracks, radio calls, the CVR (unless you intend to falsify that as well), etc...

Once filled with your falsified/reconstructed data the recorder would need to be injected into the chain of custody, which is perhaps more difficult. replacing one which has been recovered would require fooling the investigating agency, which has already seen, photographed, and cataloged the device they recovered (and would likely notice any subtle differences), or by finding the real recorder before investigators and replacing it with your forgery.

While it is not impossible to do all of the above it is highly unlikely that anyone would succeed in such a scheme.


How does a tiltrotor yaw while in vertical flight?

The V22 Osprey yaws by tilting one rotor backwards from the vertical and one forward by moving the swashplate up on one side and down on the other causing a cyclic change to the rotor blade angles of attack.  This is accomplished using the pedals in just the same way as a helicopter.

Since the rotors are tilted from the vertical, this introduces a horizontal component to the thrust vector.  The rearwards titled rotor produces a horizontal thrust component to the rear and the forwards tilted rotor produces a horizontal thrust component to the front.  This produces a turning moment, using the wings as the lever, around the centre of gravity and therefore the aircraft yaws.

The secondary effects will be as expected.  Since some of the thrust vector is no longer vertical, a little more power will be required to maintain height and I expect that there will be a pitch change although I'm not familiar enough with the aerodynamics of this type to figure out which way and how big.


How to calculate aileron deflection for achieving similar roll dynamics at thin and dense air?

Your conclusions are correct; however, it is new to me that aircraft control becomes "sluggish" at high altitude. Only when you fly up into the coffin corner will control effectivity suffer since you fly close to stall, but that is very similar to the diminishing control effectiveness when you approach stall at lower altitude.

To express your conclusions in the way it can be found in flight mechanics books:

Roll acceleration does not change with altitude because it is dominated by aileron control power and roll inertia, and
The final roll rate will change inversely with the square root of air density because here the roll damping of the wing comes in which is inversely proportional to airspeed.


What is the wing span in aspect ratio's calculation?

b is the width of the wing's projection on the horizontal plane, from tip to tip. The wing's vertical position on the fuselage does not influence b. This may or may not include winglets and ideally should be clarified when b is specified.

Calling one half of the wing a wing is sloppy use of language. Ideally, a wing half should be called that, and not be confused with a wing.


Would a perfectly silent supersonic aircraft create a sonic boom?

Sonic booms aren't created by the aircraft's engine noise. They're created by the aircraft moving through the air. The aircraft has a non-zero volume (an aircraft with zero volume is like the emperor's new clothes; you can argue all you want how much design and engineering work it took but all anyone will see is an empty spot on the flight line), meaning it must displace air as the plane passes through air. This displaced air equalizes with the surrounding air in an expanding pressure wave, which moves at the speed of sound in all directions.

As your hypothetical silent aircraft approaches the speed of sound, the air being pushed aside can no longer equalize by moving out directly in front of the aircraft. This causes a single strong compression wave to build in front of the aircraft. Similar waves have already started to build over the top of the wing surfaces, as the airflow over the leading edge of the wing (by design intended to make the air move faster thus lowering its pressure and producing lift) is temporarily supersonic before friction causes it to settle back below sonic speed; at this transition point between super- and sub-sonic, air still moving supersonically "backs up" against the subsonic airflow, creating a wall of relatively high-density air.

At this point, an observer would already hear a small sonic boom from some combination of these compression waves. However, the boom becomes much more pronounced as the entire aircraft transitions beyond Mach 1. At this point the "wall" in front of the aircraft becomes more of a "cone" as the air can no longer build up directly in front of the jet and is instead violently pushed aside at any local "disconnect" in the angle presented to the oncoming airflow. This sudden compression produces a strong shockwave "wake" which is what is heard as a sonic boom.

As a perfect example of this, there actually is (was) a vehicle that spends a very critical portion of its flight under zero engine power, effectively silent in that regard, at not only supersonic but hypersonic speeds. This vehicle, as shown in the linked YouTube, produces a characteristic "double sonic boom", proof that even a "silent" aircraft isn't silent when it's supersonic. Can you guess what it is?

The noise of an aircraft's engines could, conceivably, add a little extra to the sonic boom; the biggest difference is that immediately following the sonic boom, if you were close enough, you'd also get the engine noise, which can be deafening all by itself at full throttle up to 100 feet away.


How do the oxygen masks deploy after a cabin decompression?

According to this Airliners.net forum post,

  The masks are deployed automatically (typically when cabin altitude exceeds 14,000 feet), or can be deployed manually from the flight deck. In addition, if a passenger service unit oxygen door should fail to open, cabin crew can open the PSU door (either inserting a flat object or a special tool depending on the aircraft type) manually.

So basically, the masks are deployed automatically based on sensors, with manual deployment as a primary failsafe and physical access as a secondary failsafe.