The hinge moment is the moment acting about the hinge line of a control surface. Simply put, it is the force that must be overcome to move a particular control surface. At any given dynamic pressure and airspeed, the hinge moment will vary with angle of attack, the amount of control surface deflection, and trim tab deflection. Not an easy concept and not one which is generally taught to pilots, however becomes critical for engineers who design control systems for aircraft.


How can I learn about unpublished VFR reporting points?

Wait until the frequency isn't terribly busy on one of your flights, then just:

"Unfamiliar with Creek waypoint, Request clarification"

You can reasonably expect them to either explain the waypoint, or if they're busy, potentially give you a phone number or other contact info to try from the ground.

You can also call an Airport Manager (801-852-6715) for questions.


What is the difference between SMOH and SFOH?

The life of an aircraft engine is measured in hours of operation since some major service was done to it. When looking at ads for planes there are three regulatory terms that you'll see in engine descriptions:

New (TSN)
This one is pretty self explanatory - A brand new engine, produced with all brand new parts that comes to you right from the factory (or an authorized dealer).

  New engines have a "zero-time" logbook and no operating history because they've never been installed on an aircraft. Usually there's a "test cell run" entry in the logbook, if anything.

Rebuilt (There's not a common abbreviation here - I've seen SFRB or SFRM)
An engine that went back to the factory and was rebuilt to the same production limits as a new engine. Some of the parts in the engine will be new, some may be used, but all will meet the same standards and specifications  as a new engine.

  Only the original manufacturer can rebuild an engine, and it comes to you with a zero time logbook and no operating history (because a rebuilt engine is done by the factory and is to new-engine limits and may be made up of components from a bunch of other engines there's no way to give it a history, so it's treated the same way new engines are).

Overhauled (SMOH or SFOH)
An engine that has been completely disassembled (the crank case is split and all the parts pulled out), extensively inspected, and reassembled to either service limits or new limits. An overhaul usually includes some used parts (frequently from the same engine), and new parts as necessary to meet limits.
An overhaul can be done by the factory ("SFOH" - Since Factory Overhaul), or by a specialty engine shop, or even by your local A&P mechanic (both "SMOH" - Since Major Overhaul).

  Overhauled engines retain their operating history, and should have a complete set of logbooks since the day the engine was manufactured. Even if the only part that gets reused is the engine case an overhaul is still "the same engine" in the FAA's eyes, so make sure you can trace the full operating history of that engine.

You will sometimes see another term - "since top overhaul" (STOP or STOH), but this one is not actually defined in the regulations. Generally it means a shop removed and replaced all the cylinders (the "top end"), but did not open the crank case and thus may not have inspected the "bottom end" (crankshaft, camshaft, bearings, etc.)

The terms "overhaul" and "rebuild" are defined in 14 CFR 43.2, and further expounded upon in AC 20-62E:

  §43.2   Records of overhaul and rebuilding. (a) No person may describe
  in any required maintenance entry or form an aircraft, airframe,
  aircraft engine, propeller, appliance, or component part as being
  overhauled unless—

  (1) Using methods, techniques, and practices acceptable to the
  Administrator, it has been disassembled, cleaned, inspected, repaired
  as necessary, and reassembled; and

  (2) It has been tested in accordance with approved standards and
  technical data, or in accordance with current standards and technical
  data acceptable to the Administrator, which have been developed and
  documented by the holder of the type certificate, supplemental type
  certificate, or a material, part, process, or appliance approval under
  part 21 of this chapter.

  (b) No person may describe in any required maintenance entry or form
  an aircraft, airframe, aircraft engine, propeller, appliance, or
  component part as being rebuilt unless it has been disassembled,
  cleaned, inspected, repaired as necessary, reassembled, and tested to
  the same tolerances and limits as a new item, using either new parts
  or used parts that either conform to new part tolerances and limits or
  to approved oversized or undersized dimensions.

There is no difference between a "factory" overhaul and someone else's "major" overhaul - at least according to the regulations: The standards for what constitutes an overhaul are the same.  What is different is who you talk to if the engine breaks (for a factory overhaul you would go back to the factory, for an overhaul by an engine shop you would go to the shop, and for one by your local mechanic you would go talk to the mechanic).

If you're looking at a plane which has had an engine overhaul (the vast majority of the used piston GA fleet) you should pay attention to where it was done and the reputation of the overhauler, but given two engines, one overhauled at the Lycoming factory and the other at a reputable shop like Penn Yan Aero, they would generally be considered equivalent.


If an Osprey found itself unable to rotate its engines to vertical, what would be the emergency procedure for landing?

The Bell Helicopter V-22 Guidebook covers survivability in Appendix 1.
Specifically it refers to

Redundant Fly-by-Wire Controls
Redundant Electrical Power
Redundant Hydraulics Swashplate
Actuator Armor

implying that this possibility has been engineered to a minimum.
Nevertheless, the premise of your question is that it's occurred, so further on in the same section we see

V-22 crashworthiness is a function of design. Heavy components,  such
as the engines and transmissions, are located away from  the cabin and
cockpit area. The proprotors are designed to fray or  “broomstraw”
rather than splinter on impact with the ground. The  energy-absorbing
landing gear system is designed to attenuate  most of the energy for
hard landings up to 24 fps. The wing is  constructed to fail outboard
of the wing/fuselage attachment in a  manner that absorbs kinetic
energy and ensures the cabin area will  not be crushed, thereby
protecting the occupants. An anti-plow  bulkhead prevents the nose
from digging in on impact, and the  fuselage provides a reinforced
shell that is designed to maintain 85%  of its volume during a crash.
Aircrew and embarked troops receive  additional protection from
crashworthy seats that stroke vertically to  absorb energy

(my emphasis)
Since the aircraft is still flying, I'd head for the nearest decently equipped airfield, conduct a normal fixed wing approach and land, trusting that the rotors will sweep a nice clean path along the runway instead of peppering the fuselage with shrapnel. I'd probably take the precaution of cutting power early to reduce the kinetic energy in the rotors before they hit the ground.


"Fundamental of Aerodynamics" 5th editon, example about oblique shock. Is the author's solution wrong?

Continue reading, I have found the answer. Look at problem 9.3, page 663:

And here is the author's solution:


For the same airspeed does the attitude of an airplane change with varying wind directions?

If by attitude you mean pitch attitude or angle of attack (which is how I automatically understood this), no it does not change as this is related to the aircraft's airspeed through the air. So an aircraft flying downwind will have the same AOA as the same aircraft at the same airspeed flying upwind.

If you want to fly at the same groundspeed upwind as downwind, then you would have to vary your airspeed, which means varying you pitch attitude or AOA. This might not be possible if say you were in a light aircraft in a 40 knot wind at altitude which cruises at 100 knots.


What are the FAA regulations on operating UAVs in class E airspace above FL600?

The FAA limits drone operations to 400 Ft. so getting to FL600 is not really possible.

  Cannot be flown higher than 400 feet above ground level (AGL), unless
  flown within a 400-foot radius of a structure and does not fly higher
  than 400 feet above the structure’s immediate uppermost limit;

The FAA does offer a waiver process for flying drones beyond the regular part 107 rules. You can find all the info on that here. The request to operate in controlled airspace form does ask for a max altitude so its possible it can be requested.

However someone in Russia appears to have flown their drone up to FL330 so it may be allowed there.


Can a captain fly in the right seat as SIC under part 129?

From the regulations:

  Each person acting as a flightcrew member must hold a certificate or
  license that shows the person's ability to perform duties in
  connection with the operation of the aircraft. The certificate or
  license must have been issued or rendered valid by:

  (a) The State in which the aircraft is registered; or

  (b) The State of the Operator, provided that the State of the Operator
  and the State of Registry have entered into an agreement under Article
  83bis of the Convention on International Civil Aviation that covers
  the aircraft.

Since a captain can always fulfill the duties of a first officer, then yes, someone who normally occupies the left seat can occupy the right seat.


Why does indicated airspeed change with altitude?

As you state, IAS is simply based upon the difference between total pressure and static pressure. For low subsonic conditions:

$$ p_t = p_s + p_q = p_s + \frac {1}{2} \cdot \rho \cdot V^2$$

$\rho$ is the air density, which is a function of air temperature: $\rho = \frac {p_s}{R \cdot T}$. For indicated airspeed, the density at sea level $\rho_{SL}$ at 15 degC is taken:

$$ V_i = \sqrt {\frac{2 \cdot (p_t - p_s)}{\rho_{SL}}}$$

However, the actual dynamic pressure measured by the pitot tube is caused by actual density.

When temperature decreases, density increases.
So at colder temperatures, some of the dynamic pressure is due to higher $\rho$
Therefore, the $V_{ind}$ bit decreases. The pitot only measures dynamic pressure and does not know what is due to temperature

Air is colder at higher altitude if we stay in the troposphere - climb to over 33,000 ft and the IAS does not change anymore.


Where does this integral for a 'aerospike nozzle' come from?

I expect you know how a conventional rocket nozzle works: It expands the exhaust gas, and the pressure inside helps to increase thrust, pushing the nozzle forward.

Now turn the conventional nozzle inside out. The expansion happens on its outside, but there is still a pressure acting on a backward-facing surface. The graph doesn't explain it, but the ramp area $\text{A}_{\text{Ramp}}$ is the projection of the nozzle area in flight direction. The ramp pressure $\text{p}_{\text{Ramp}}$ is the pressure acting along the nozzle surface, and it must be reduced by ambient pressure $\text{p}_{\infty}$ in order to arrive at the correct thrust. The integration is needed because $\text{p}_{\text{Ramp}}$ varies over the nozzle area.


Why is a rectangular wing planform less efficient than others?

For the same wing span, an elliptical wing planform is the most aerodynamically efficient compared to any other flat wing planform because it has the lowest induced drag. Note that we are comparing only aerodynamics here. Things get much more nuanced once you couple structural weights, stability & control for a global efficiency (also see @Peter's answer).

1. Induced drag

So restricting to aerodynamics, elliptical wing planform is the most efficient because it has the lowest induced drag. Induced drag is produced because wings have finite span, and therefore one section of the wing distorts the flow on another section, creating downwash. This downwash distorts the lift vector on each wing section, thereby converting what otherwise would be lift into drag.

2. Downwash

Now that you understand induced drag has to do with downwash on each span section, you must appreciate that the distribution of downwash over the span is important to the induced drag generation. Distribution of downwash is dictated completely by the lift distribution over the wing (and vice-versa), which is in turn, dictated by the shape of the wing planform.

3. Lift distribution

For an elliptical wing planform, we can prove that it also generates an elliptical lift distribution. When you do the math of integrating all the sectional induced drag from the downwash and sectional lift, elliptical lift distribution has the lowest induced drag.

The following figures show the distributions of elliptical wing, rectangular wing (taper = 1) and tapered wing (taper = 0.5), with aspect ratio 8 and all producing a total $C_L=0.4$. Here, Ref Cl is the actual lift coefficient distribution that we've talking about, but multiplied by span length; Local Cl is the lift coefficient produced at each wing section, as if it's standalone airfoil; $\alpha_i$ is the downwash distribution in deg. The data are generated from Lifting Line Theory.

As you can see, elliptical distribution maintains a constant downwash, compare that to a wider and more varied one for a rectangular wing. Also, a taper of 0.5 gets you fairly close to the elliptical lift and downwash distributions, especially when you consider the $\frac{C_L}{C_{D_i}}$, which is 62.8 for elliptical and 61.8 for tapered.


Why are turbine blades not made out of titanium, only compressor blades?

Titanium is unsuitable because it will react with oxygen and carbon at high temperature, well below its melting point, making it very hard and brittle. Welding titanium is very complicated because it needs to be shielded extremely well from any oxygen when hot. Ti$_3$O will form above 500°C, and Ti$_2$O above 600°C.

Initially turbine blades were made of steel alloys, but they have been displaced by nickel alloys.

Also, they operate in an environment which requires constant cooling, so they can be 200 - 300°C cooler than the turbine entry temperature of the gas coming from the combustor(s). Modern turbine blades are hollow and have a perforation at their leading edge. Pressurized, relatively cool air is forced through the blades and the perforation and flows around the blade's surface, creating a cool sheet of air to shield the blade from the hot gas. Also, before entering the turbine the gas is accelerated, which already lowers its temperature. See the plot below of parameters inside an older engine taken from this source.

Shortly past the fuel injectors the maximum gas temperature of approx. 1800°C is reached, which drops to 1100°C at the entry to the first turbine stage. Note that this temperature has been raised to 1500°C in modern military engines! At the same time, the highest temperature is connected with the lowest speed (30 m/s), and the flow accelerates to 200 m/s directly before entering the first turbine stage.

Titanium in contact with oxygen would lose a lot of its strength at these temperatures, even though its melting point is at 1650°C.


For a private GA pilot, when is an endorsement needed for a particular type of aircraft?

There are two aspects here, one what is required legally and then what may be required locally.

From a legal standpoint (in your case) the basic PPL will allow you to fly single engine, fixed pitch prop, under 200HP, fixed gear aircraft. If you want to go over 200 HP you will need a High Performance check out and log book endorsement. For a constant speed prop/folding gear/movable flap (all 3 are required to require this endorsement) plane you will need a complex endorsement in your log book. You may want to fly something like a Piper Cub which will require a tail wheel endorsement. If you are lucky enough (and have the funding to do so) you may find your self in a small pressurized single (or twin) like the Piper Meridian or TBM 900 these planes will require a high altitude checkout as well. AOPA has a nice summary of the endorsements here. If you want the full FAA FAR regs you can find them here.

Now as for a club or school that depends on a variety of factors including their insurance and their personal limits. I'll offer some personal experience which seems to be pretty par for the course. The flight school I fly from requires a checkout in type from every new renter before you can fly it even if you have a PPL and the proper endorsements. They don't have an official amount of time but it usually takes about an hour with an instructor. The former flight school I was at had the same deal with the exception of their Saratoga which they also required an instrument rating (along with their checkout).

My buddy's flight club is somewhat similar. They require a check out in their Archer and Dakota to fly solo. They also have a Lance which they require 25 hours time in type and a 5 hour check out in the plane.

As for your log book you should be logging the full type of aircraft for every flight. For example when I fly the Warrior I make sure to note PA-28-161 and the Archer I fly is noted as PA-28-181 when I record hours this way I can note time in type at a detailed level.

For what its worth with the PA-28 airframe it seems that some places to allow you to fly the lower rated planes if you are checked out in the higher power ones. The same basic frame was built in a 140, 160, 180 and 235HP variant over the years and has little differences aside from useful load and V speeds. For example at the place I go if you are checked out in the Archer first you are allowed to fly the Warrior with out a checkout.

This will also extend to ownership should that be the path you go down. In that case you insurance company may require a certain amount of hours of time in type before you are allowed to solo your plane. Keeping that in mind you are not actually prevented from buying the plane and will be insured under the stipulation that the first hours in the plane are with an instructor. When a buddy of mine (instrument rated and close to 600 hours at the time) upgraded from his 72 Archer to a 95 Saratoga HP his insurance company mandated he do 25 hours in type with an instructor before taking the plane solo. The first 25 hours he flew his plane were with an instructor (this included transporting the plane from the factory in Vero Beach to his home field).

You can legally fly both planes once you have your PPL. What someone will let you fly should be pretty well addressed above. Neither the 172 or 152 requires a specific type rating like larger planes do.


How to record flights and cockpit radio com using an Android phone?

Android by default has Google Now enables, which include voice search. Voice search listens for the words "Ok Google" when you speak, but phones also detect a long press in a headphone button (on headphones with controls). It can also be fooled into activating by odd signals like the pop when you turn on the avionics master switch or loud droning noises like motorcycle and airplane engines.

First thing I would try is to turn off the voice detection, see this page for instructions. Now google voice should stop popping up if the phone is being fooled by noise.

However, that may not be the end of it if the phone is detecting static or other signals as a long headphone control press, in which case it may still interrupt your setup. In that case you will need to use an app to disable the headphone controls, the one I've heard of is SoundAbout, or your phone's distribution may have settings to let you do it.


Why aren't there any single turbofan airliner?

Airliner designs must be certified in order to fly commercial services. In the US, this means compliance with the Code of Federal Regulations, Title 14, Subchapter C, Part 25. In §25.901(c) it says:

  For each powerplant and auxiliary power unit installation, it must
  be established that no single failure or malfunction or probable
  combination of failures will jeopardize the safe operation of the
  airplane except that the failure of structural elements need not be
  considered if the probability of such failure is extremely remote.

Engines do fail from time to time, so there must be a second unit which can take over if one fails. It's the same for fuel pumps, instruments or even wheels: Every one has a second unit which can take over if the first fails. For wheels, this is very easy to check: You will not find a single airliner landing gear leg which has only one wheel. All have two wheels or more.

Or pilots: The minimum number of pilots for safe operation is two. One can fly the plane (so she/he can land it if the other pilot is incapacitated), but two are needed to start any revenue flight.

I could continue that list, but I guess the concept has become clear: For every element on an airliner there needs to be a second, redundant one, except for structural elements with a very remote probability of failure.

This has been learned the hard way: Some of the first aircraft designed for passenger service (like the Junkers F-13 or the Fokker F.II) had a single engine. Some of the multi-engined ones even became dangerous death traps when one engine failed. Over time, the desire to increase safety made redundancy the supreme design principle for airliners.

Military operators have fewer qualms about single engine designs, because using fewer engines improves performance and lowers acquisition and operation cost.


How are the frequency pairings for localizer and glideslope decided?

As always the country is responsible for the final decision, so FAA/FCC will decide in the US (but see @Gerry 's comment from an insider below), and I believe so does the MIC in Japan. However this local decision happens after an agreement already found in international bodies. For aviation, the international body is ICAO and ICAO Chicago Convention is the main framework used to ensure international aviation operations are possible, safe and fair:

The localizer / glide path pairing table is part of Annex 10 of the Convention, Volume I, paragraph 3.1.6.

  3.1.6.1 The pairing of the runway localizer and glide path transmitter
  frequencies of an instrument landing system shall be taken from the
  following list in accordance with the provisions of Volume V, Chapter
  4, 4.2.

ICAO decisions in radiocommunication matters are subject to the frequency allotment and protection decisions taken under the auspices of the ITU during the World Radiocommunication Conference (WRC), held every four years. It's ITU which is responsible for the global (civil) use of the frequency spectrum.

The pairing table was built back in 1956! (Fifth Session of the COM
Division, as visible on p. XI)

Pairing was carefully designed so that ILS could work without interferences (harmonic and heterodyne) in certain conditions without being below the radio horizon of each other.

A preferred pairing table is provided for such use:

  3.1.6.1.1 In those regions where the requirements for runway
  localizer and glide path transmitter frequencies of an instrument
  landing system do not justify more than 20 pairs, they shall be
  selected sequentially, as required, from the following list:

Attachment C of Annex 10, (2.6 Deployment of ILS frequencies) provides some details about this selection:

  2.6.5 In general, when international use of ILS systems is confined to the pairings listed in Chapter 3, 3.1.6.1.1, the criteria are such
  that, provided they are met for the localizer element, the glide path
  element is automatically covered. At certain congested locations,
  where it is necessary to make assignments in both the first ten and
  the second ten sequence pairings, it may be necessary to select
  certain pairings out of sequence in order to meet the minimum
  geographical separation in 2.6.6.

  Example: Referring to Chapter 3, 3.1.6.1.1, it will be noted that ILS
  Sequence Number 2 pairs the localizer frequency of 109.9 MHz with
  glide path frequency 333.8 MHz. Sequence Numbers 12 and 19, however,
  although providing wide frequency separation from Sequence Number 2 in
  the case of the localizers, assign frequencies of 334.1 MHz and 333.5
  MHz, respectively, for the glide paths, both being first adjacent
  channels (300 kHz spacing) to the Sequence Number 2 glide path
  channel. If selection of ILS channels is confined to either the first
  ten or the second ten pairings, then the minimum glide path frequency
  separation will be 600 kHz.


Apples and oranges. A PIREP is a report of current weather conditions at a specific location. An AIREP is primarily a position report, required of some aircraft that are not under radar control. Whereas the primary purpose of a PIREP is to report unusual weather conditions or things like turbulence and are not mandatory, AIREP's are in many cases mandatory and weather information in Section 3 is optional.


What is the cart and cable connected to this plane?

On further investigation, thats an A320 rather than a 757, and the A320 Airport and Maintenance Planning document shows that that hookup is the ground power port (page 206).

The stairs are for passing documentation up to the cockpit side windows, which open.


Is there a viable alternative to liquid hydrogen as a fuel for scramjets?

To list possible alternatives, it is helpful to know why hydrogen is used for scramjets today. The key is the speed of propagation of a combustion in the hydrogen-oxygen mixture.

In order for combustion to take place, the fuel needs to mix with the air and then the ignition needs to propagate fast enough through that mixture in order to allow the combustion to stay stationary relative to the engine. Combustion which happens after the fuel-air mixture has exited the nozzle of the engine is not helping in propulsion.

Therefore, to be suitable as a scramjet fuel, the candidate has to

mix with air really quickly,
have a flame front speed higher than the flow speed in the scramjet, and
achieve complete combustion as quickly as possible.

In all points hydrogen is hard to beat. It is so good that scramjet designers have decided to accept it as their favorite fuel despite of all its disadvantages, which are well known:

Low volumetric efficiency, even in liquid form.
Storage in a cryogenic or high pressure tank.
Small molecular size, so it diffuses into and leaks through many materials, even metals.

All bullet points can more or less directly be traced back to the small size of the hydrogen molecule. Any other scramjet candidate would also benefit from a small molecular size, and acetylene would be the next best candidate, with a flame front speed of 168 cm/s at room temperature (compared to the 364 cm/s of hydrogen).

The difference in speed makes clear that no other fuel comes close to hydrogen.


Where could I find a MATLAB implementation of TCAS algorithms?

MIT LL did indeed build a TCAS model in Simulink/Matlab which was used to validate the algorithms. I doubt they will release it, but it's worth trying to start there.

Otherwise, they did release quite a bit of details in reports. You'll probably end up rebuilding it from their logic.


Has reversing the active runway direction ever led to lined-up aircraft taxiing to the other end of the runway?

What you are describing does happen. The runway change is a major event at a big airport and it usually occurs once a day. This becomes a major transition because landing aircraft have to be switched to the other end. AND, areas served by a single approach control, the change has to be coordinated with the other airports. Note that lines of aircraft waiting to take off rarely occur unless the airport is very busy and has few runways.

Thus, the runway change generally occurs over time (half an hour).

If there is a sudden, unpredicted wind change, generally, aircraft that are already at the "wrong" end of the runway are allowed to continue using it if they are able to do so.

So yes, aircraft will on occasion have to move to the other end of the runway.

I have seen this more frequently at busy general aviation airports than at commercial airport.


Can experts identify the model using this part (FOD prevention purposes)?

This is a Military Standard fuel cap, part number MS29525-1.

Here is the DOD page for the products: MS29525-1. It is most likely from a military aircraft or some kind of private ex-military warbird.

There really isn't much to say on it, other than it is used by the Air Force and Navy, as well as some British aircraft. It is a universal part used on many different types. It is a serialized part, you could try calling a local airbase and see if you can get records for it, but they will probably not care enough to track it down.

By the way, whoever is missing it, if a private party, paid a dear price for losing it. The cost of these caps in the private market range from \$600 to \$800.


What are the limits to lateral Centre of Gravity imbalances?

Lateral c.g. limits are prescribed for large aircraft both for max fuel imbalance and for what is being carried in the fuselage. It's basically impossible to exceed the max lateral imbalance in a passenger aircraft. Exceeding the max in wide body cargo aircraft can be done and is checked for, but it takes an unusual load to exceed the max.

The 747-400, for example, has a max lateral imbalance of 10,000,000 inch-pounds. If you load 207,205 lbs on one side only of the main deck of a 747-400 freighter using size code M pallets, you will exceed the maximum. To see this happen (if you're using Firefox or Chrome--IE won't work) go to 747.terryliittschwager.com, dismiss the flash screen, and then click on test load #6 near the bottom of the page. That will trigger exceeding the lateral imbalance limit. Scroll down to the Lateral Load Imbalance graphic to see the max lateral loading envelope and the point that shows the load exceeding it.

Here are some approximate weights for a 747-400 freighter:

basic operating weight 365,000 lbs

max fuel 360,000 lbs

max cargo 245,000 lbs given the 610,000 max zero fuel limitation and a 365,000 bow

Note that you cannot carry max fuel and max cargo. A common 747-400 max takeoff weight is 875,000 lbs.


Straight from the FAA:

  Airworthiness Directives (ADs) are legally enforceable rules issued by the FAA in accordance with 14 CFR part 39 to correct an unsafe condition in a product. 14 CFR part 39 defines a product as an aircraft, aircraft engine, propeller, or appliance.

When an aircraft or other component is found to have flaws or other issues, the FAA will issue an AD specifying a solution to be applied to the item. The AD must be complied with, often by a date or total time on the airframe. The action required could simply be an inspection (often recurring after, say, 100 hours of time in service), while in other cases requires modification, strengthening, or replacement of parts.

One of the more prominent cases requiring ADs to be issued was the V-tail Bonanza, which had issues with the tail's structural integrity under high loads.

The cost of complying with an AD falls on the owner/operator of the aircraft. Failing to comply with an AD renders the aircraft unairworthy. It also could incur FAA penalties, but more importantly, it could result in structural damage or failure, and in some cases ultimately cause a fatal accident.


What is the role of a CFI (not CFII) as safety pilot for hood time?

The bottom line is that it is up to you. It would be very beneficial to get as much simulated IFR time as possible. It does not matter if it is with your school CFII, a school student, the club CFI, a club student, or an unaffiliated and current pilot friend. Your CFII should not have a problem with that. Instruction (and the cost of it) is about you, not him. Although, they may have a legitimate concern about the quality of training you are receiving outside of the school. And, be wary of training in aircraft that are too different from one another, even in the same make and model.
The benefits of doing IFR time with your school CFII are:

It counts towards dual instruction time.
Your instruction stays consistent in structure.
The CFII will be able to give you the gouge (predisposition of questioning and testing) of the DPE.
The CFII is already familiar with your deficiencies.

The benefits of doing IFR time with the club CFI:

It counts as PIC and IFR time even if it does not count as dual instruction.
Costs less than the school.
You get a different perspective, tools, tips and tricks from an instructor qualified, instrument rated pilot.
A new/different set of eyes may uncover different deficiencies.
Typically, club instructors are going to stick around and have more longevity than school instructors. Although, this may not always be the case. It will give you an opportunity to build camaraderie and community for the future. After all, who is going to give you your Flight Reviews and Instrument Proficiency Checks.

The benefits of doing IFR time with another student:

Another student may have picked up something different but useful in training than you did.
Collaborative learning.
Building community and networking for the future.
Cuts out the cost of an instructor.
If it is a school student, their training will be consistent with yours (supposedly).
If it is a club student, they may have been trained completely differently. You may be able to glean useful tidbits from that different training.
You get to double your total flight/PIC time when trading off safety pilot-flying pilot responsibilities.
Flying! ‘Nough said.

The benefits of doing IFR time with a current and proficient, unaffiliated pilot friend:

Again, Flying! Flying is winning.
Totally different perspective. Remember, a good pilot is always learning, even from other pilots.
Camaraderie, community, networking, friendships, and that $100 burger/breakfast/BBQ.
You can fly any aircraft that you want. Although, it may not count as total and/or PIC time if you are not certificated for that category, class, and type rating if applicable unless the friend is also a CFI.
And of course, money. You can fly something cheap. Ty to find someone who owns their own aircraft.

Lastly, never overlook or underestimate the value of just sitting in the backseat with your headphones on and your mouth shut during another student’s lesson. You may pick up a lot of valuable information when you don’t have the added burden of flying the aircraft. Even if you can’t actually log the time.
As far as the “legal bind” that you mentioned. Any and all pilots acting as PIC will be in a legal bind if something goes wrong. After all, they are PIC for the purposes of safety of flight. That is the responsibility of their certificate. Any PIC who currently or in the future earns a living from their commercial license of any type will have more at stake than a recreational pilot.


What are the circled features on the upper surface of the A380 wing?

They are likely attach points for safety harness equipment. Workers working on top of the wing attach gear that functions as anchors for lines that run the length of the wing, then attach their safety harness to the line.


What are the most popular areas to do private pilot flight training in the United States?

The FAA has a document on their website which breaks knowledge tests down by FSDO rather than state, and it gives a good idea of where the most training is taking place.
It is called: 2013 Airmen Knowledge Tests by Region and FSDO, and lists the following Regions/FSDO's as processing the most knowledge tests (in descending order)1:

Southern 28,333
Orlando 9,996
South Florida 5,958
Alabama & NW Florida 4,680
Atlanta 3,882
Tampa 2,504
Western Pacific 18,416
Scottsdale 6,053
Riverside 1,556
San Diego 1,463
Sacramento 1,460
Long Beach 1,327
Fresno 1,270
Los Angeles 1,142
San Jose 1,121
Southwest 15,943
Dallas 2,731
Fort Worth 2,581
Houston 2,438
Oklahoma City 2,347
San Antonio 2,321
Eastern 14,552
Richmond 1,956
Greensboro 1,366
Farmingdale 1,280
Philadelphia 1,198
New York City 1,069
Boston 1,041
Great Lakes 11,860
Fargo 2,120
Dupage 1,414
Indianapolis 1,358
Minneapolis 1,142
East Michigan 1,111
Northwest Mountain 9,784
Denver 2,205
Portland 2,131
Salt Lake City 1,964
Seattle 1,611
Central 9,019
Nashville 4,293
Wichita 1,304
Alaskan 812

Based on this data, I would say that the areas surrounding the Orlando, Scottsdale, South Florida, Alabama & NW Florida, Nashville, and Atlanta FSDO's are the most popular training areas, with the Southern region being the most popular by far.

1 To improve readability, all FSDO's with less than 1,000 tests have been removed.  See the source data for the complete list.


What is the Beggs/Mueller emergency spin recovery technique?

The Beggs/Mueller technique is:

engine idle
let go of the stick
push rudder against spin direction

This was developed for pilots of the Pitts Special biplane and will work well with naturally stable, powered aircraft. With gliders (where it strictly doesn't apply) it will be less effective, but still work in most cases. The better way is to combine both, rudder against the spin and stick forward (your PARE technique), but only until the rotation stops. Then both the stick and the rudder must be neutral until speed is sufficient for the pull-out. Beggs/Mueller is more about avoiding wrong inputs due to confusion than ending the spin in the most direct way.

Spin recovery with the hands off the stick will be slower than with active control input. If the control surfaces are free-floating, natural stability is normally less than what it is with fixed control surfaces. For that reason, the Beggs/Mueller technique is less effective than actively ending the spin with both rudder and elevator. If the pilot does not realize he is in an inverted spin, pushing down will make matters worse, however.

Why rudder against spin direction?

An aircraft spins because something stabilizes both the rotation and the high pitch angle. First the rotation: This is caused by fully separated airflow on the retreating wing while some section on the advancing wing has attached airflow. The high drag on the retreating wing pulls this side of the aircraft backwards, while the lift on the section of wing with attached airflow pulls that side of the aircraft forward. Remember, airflow is mostly coming from below, and the spin motion modifies the local flow direction the more one moves away from the center of the aircraft.

Why elevator forward (Back in inverted spin)?

Now the pitch angle: The center of rotation is ahead of the wing in the forward fuselage. The masses in the forward fuselage produce little centrifugal force, while the masses in the rear fuselage and the tail, having a substantial distance from the center of rotation, produce a substantial centrifugal force which pulls the whole aircraft into a level attitude. Since the aircraft's motion is mainly downward, this inertial moment increases the angle of attack above the stall angle.

To break the spin one needs to end the rotation or the pitch attitude. Since they mutually reinforce each other, one must be ended to end both. On aircraft with long fuselages the rudder is more effective to stop the rotation, while on aircraft with long wings the elevator will be more effective in ending the spin via reducing pitch attitude. The rotation is then stopped by the roll damping of the wing. Using both together will give the best effect, however.

Why engine to idle?

Having some added dynamic pressure on the vertical tail will also help to end the rotation, but then the aircraft will pick up speed very quickly. Setting the engine to idle will avoid falling into this particular trap, but again for the price of a somewhat slower recovery. Sometimes an aircraft needs that added dynamic pressure to end the rotation, so Beggs/Mueller will not work in all cases.


Why is the CG envelope wider when the aircraft is heavy?

So if I understand that correctly the CG can be more forward when the aircarft is heavy.

Not really, although I guess you could say the index can move "forward" because of the way the form is drawn, but the index is not the CG. Indices are a composite number, namely the moment divided by a reduction factor.

The use of index numbers and a reduction factor greatly simplifies
weight and balance calculations, especially for large aircraft. The
index is a moment divided by a reduction factor and may be found by
this formula:
Index = (Weight x Arm) / Reduction factor
(from http://avstop.com/ac/weightbalance/ch4.html)

While indices make manual calculations easier than using %MAC and weight (the way computerized systems typically do it), they do tend to obscure things in my opinion.
If you want to see a 747's weight and balance envelopes using %MAC and weight, go to 747.terryliittschwager.com and select any 747. The top one on the aircraft list will do, N402YY. When the aircraft comes up, scroll down to OPERATING ENVELOPES.
You can position your pointer over the vertices to see their values. Note that the forward limit for takeoff at 580000 lbs is 11.0 %MAC, staying at that limit up to 778000. Getting heavier from there moves the forward limit aft, not forward, and additional weight from there really sends it aft.
The forward limit for the zero fuel and landing envelopes stays constant throughout the weights of their range.


What is a good plane for aerial photography?

I used to work at a sport parachuting center - we occasionally had photographers rent one of our Cessna 182 airplanes for the same purpose. An advantage of jump planes is the pilots are quite used to odd attitudes (and even odder requests) so a 60 degree bank angle with the door open and you leaning out of it will get a reply of "no problem".

Our conditions were the photographer wears a parachute, a seatbelt, and if the camera goes for a jump that's just too bad for your wallet. 30 minute lecture on what to do if you fall out. Short form: drop camera, grab this handle, pull. And the trip's over if you do anything silly.

You would sit on the floor where the co-pilot's seat would normally be, the pilot will open the door as needed, and you have a clear view out the right rear quarter of the plane. Obstacles are the wheel (front half of the door looking down) and wing strut (forward) - the tail is well out of the way. It's very noisy, but unless your camera is actually outside the fuselage the wind blast is not an issue. Don't change lenses though, and your clip-on lens hood will probably disappear rather quickly.

You can sit on the door ledge with your feet outside and have an excellent, stable field of view with both hands free to operate your camera. I've sat there hundreds of times without a seatbelt, it's no problem even in steep turns. Just a bit odd seeing the ground above the wingtip. Difference is, I don't care if I fall out.


Jet bridges are operated just next to the point at which passengers will enter the aircraft. They have proximity sensors that tell the operator if they getting too close. And the bridge doesn't have to physically touch the aircraft as long as the gap on the walkway is small enough to not pose a danger to the passengers, it just needs to get close enough so that the end of the bridge can extend like an awning and cover the entrance. The parts that do touch the aircraft are usually made of material that will not damage the surface of the airframe.


How to calculate the real Ground Speed from True Air Speed?

First calculate horizontal component of airspeed, then add the wind:

$$v_{GS} = cos(\theta) * v_{TAS} + v_{wind}$$ with $\theta$ being the angle between the horizon and the path of the aircraft in the vertical plane.

Or, if you are unfamiliar with trigonometry (using Pythagora's theorem):

$$ v_{GS} = \sqrt{v_{TAS}^2-v_{verticalSpeed}^2} + v_{wind}$$

Both formulas assume the same units being used for all speeds ($v_{TAS}$, $v_{verticalSpeed}$, $v_{wind}$), and only take horizontal wind into consideration. $v_{wind}$ is only considering the headwind/tailwind component.


Can small airplanes dump fuel during flight?

The short answer is, no, generally only large aircraft have purpose-built fuel dumping systems. Such a system may be helpful in reducing aircraft gross weight to a safe landing weight in the case of a precautionary landing. The approved landing weight of smaller aircraft, such as the C172, is generally the same as the approved takeoff weight.

The longer answer is, yes, it would be possible to "dump" fuel from an aircraft such as a C172, though not by means of a purpose built mechanism. The "dumping" would be more of a slow to moderately fast drain, depending on the means used.

If I wanted to drain the fuel from one of the wing tanks in a C172 while in flight I could use a pen, screw or other such device to drain fuel from the wing tank sump. A faster dumping/draining method—though requiring considerably more work—would be to unscrew and remove the fuel drain valve, thereby releasing all the fuel in the wing. Obviously, this later method would hamper the possibility of draining only a portion of the fuel from the wing tank.

I cannot think of any reason why I would want to drain the fuel in flight apart from reducing the risk of fire in the event of an emergency landing. And in that case, my prefered method of reducing the risk of a post-landing fire would be to concentrate my efforts on the landing, not on eliminating a fuel source.

Generally, I prefer to have more rather than less fuel in the tanks when I fly.


Is there any source of live ATC audio with subtitles?

Not live with subtitles, but there are certainly plenty of ATC/pilot recordings on youtube
https://www.youtube.com/results?search_query=atc+conversations

Plus Live ATC streams. I can't access these (lousy cell phone coverage), give them a try.
https://www.liveatc.net/topfeeds.php


Is it incorrect to say that "passenger jets like to cruise at higher altitudes because there's less drag"?

There's less drag at the same speed (and other things being equal, aside from altitude).
This is due to lower air density at higher altitude, which linearly affects drag. But just the same, it affects lift! You get less drag, but less lift too. If you want to fly level, you can't afford that: lift must be equal weight.
So what do you do to restore lift? You either fly faster, or increase angle of attack (AoA), or both. Either way, drag will roughly be the same.
Flying faster with the same drag is the benefit. However, sooner or later you'll hit the speed limit. (Most commonly for jets, this will be the Mach limit). From then on, you can only increase AoA.
Changing the AoA affects the L/D ratio. It may increase or decrease, depending on how the wing was designed. There is a certain AoA which will be the 'best'. If the jet was optimised for cruise, it will fly close to that angle.
Does it make any sense to fly even higher, where you have to increase AoA past the best L/D angle? It might, but not much. Primarily because you might squeeze a little better fuel consumption in colder air (that SFC component), so the optimum may be slightly higher. But flying at a higher-than-optimal AoA may be unstable by speed. (Which is manageable, but is another difficulty you don't want).
At some point, you will exhaust either the AoA, getting dangerously close to stall (while, remember, being at the speed limit at the same time - the so called 'coffin corner'), or thrust: it will keep reducing in thinner air, until it becomes lower than drag. That's your ceiling.


Does anxiety increase the likelihood of developing motion sickness?

It's different for everyone, but I'd expect stress/anxiety to be a contributing factor for many, which is an ultimately self-defeating cycle; if you "know" you're going to get sick, you'll be anxious about that, and that'll make you sick.

The trigger for me is inadequate ventilation. I'm fortunate enough to rarely get motion sickness, but when it does happen it's usually because I'm in a hot, still cabin without a good source of fresh air.


What is the non-projected cross-hair for on the F-18 HUD?

It is a "Standby Reticle":

  A fixed standby reticle (Figure 7–151) is available in the upper right side of the HUD for use in performing visual designations in the event of a HUD failure. The reticle is fixed at a 15-mil depression angle from the gun boresight. If the HUD fails, the HUD symbology is available by selecting HUD via the menu on the left or right DDI [Digital Display Indicator]. To perform a HUD designation in the NAV or A/G [Air/Ground] mode when the HUD is inoperative, the pilot first places TDC [Target Designator Control] priority to the HUD (either by placing the sensor switch to the normal HUD position, or to the left or right DDI displaying the HUD symbology). The mission computer slaves the radar in AGR mode to the LOS [line of sight] of the HUD standby reticle. The pilot maneuvers the aircraft to position the standby reticle over the aim point and actuates the TDC to perform the designation. The aim point position at the LOS of the standby reticle is computed. The pilot may use the HUD display on the left or right DDI to null the steering error when automatic weapon delivery is being conducted.

Source: ED Forums

The standby reticle is used when the HUD fails for designating targets. The pilot must lean to the right and line up the cross-hairs with the dot so that the bore-sight is accurate.


Could the experience of inflatable structures in boats be applied to large aircraft design?

We now have experimental use of inflatables in space as well as for boats.

If an aircraft's engines are responsible for the inflation of any aerodynamic or structural part of the aircraft, however, one would have to answer what happens if the engines stop. A conventional aircraft whose engines fail at a sufficiently high altitude can glide for some time, giving the crew a chance to restart the engines; it may even be landed without engine power if necessary. This is a very bad time for the aircraft to lose aerodynamic performance or structural strength--for example, for the winglets to deflate just when the crew need the best possible glide slope.

Unlike boats or spacecraft, moreover, most conventional aircraft are intended to descend from altitudes of low pressure to altitudes of high pressure. If the amount of gas in an inflatable structure is held constant, one has to balance structural rigidity at low altitudes against the stress on the fabric from the much greater pressure difference at high altitudes. If the amount is not constant, it has to be replenished during descent. The engines cannot be relied on to do this, since the reason for descent may be engine failure. Gas could be supplied from high-pressure cylinders, but those can be heavy.

For an aircraft not intended to climb very high, these concerns are less severe.


How many turns of a 737 trim wheel equal 2.5 degrees stabilizer deflection?

About 45 Rotations

In this YouTube video you can see Mentour pilot demonstrating manual trimming of a Boeing 737 NG. They start at about 11:30 with:

  we have 4 units nose down now

and at 12:30 they say:

  now we are at about 3 degrees

I counted 18 full rotations of the trim wheel in this time. This would result in

$$ \frac{18}{4^\circ - 3^\circ} \times 2.5^\circ = 45 $$

rotations for 2.5 degrees of trim change.

Note that the trim indicator is not very precise, so the number is only an estimate:

(frame from the video)


Could a civilian aircraft in distress land in Area 51?

R-4808, the restricted area around Groom Lake, NV, is restricted at all altitudes.  It is also surrounded on multiple sides by other restricted spaces and MOAs.

No routes, low-altitude or high-altitude, go through the area.  No one has any business being near there to begin with, so no one will have any emergencies in the area.


Are airfoil profiles patented? If not, why?

There certainly are airfoils that are patented. Here is an example. Here is another airfoil by the famous aerodynamicist Richard Whitcomb. I think it is tricky in practice to obtain a patent in that you need to define the airfoil in a way that isn't so narrow as to be useless for protection. Just claiming a series of coordinates would provide very little protection as someone could make minor changes to avoid infringement.


Why choose to ditch in the sea over bailing out?

Bailing out the cockpit during that era was neither an easy nor always a successful task. The pilot had to either roll the plane, open the canopy, and release themselves to the void, or if rolling wasn't possible, walk on the wing and jump.

That's inherently unsafe. Don't forget that you are not exiting a healthy plane. There might be smoke, debris, fire, propellers spinning, the tail that might cross your way out.

Read what happened to Hans-Joachim Marseille when he tried to bail out. Quote from Wikipedia:

  the left side of his chest striking the vertical stabiliser of his fighter, either killing him instantly or rendering him unconscious to the point that he could not deploy his parachute.

Now, regarding ditching versus bailing out, I don't have any source to substantiate the chances of survival, because in the end, what matters is to get out of there alive. But I guess it depends on many factors, one of them being the sea state as they mention in the film.

Another one is the type of damage the airframe has sustained. It might be better to risk a "gentle" contact with the water if there is no "urgent reason" to leave the plane and you can ditch reasonably soon, than to exit the cockpit and increase the chance of being injured by anything that I've mentioned in the first paragraph.

Finally, it turns out that the choice heavily depends on the situation. I haven't seen the movie so besides the "sea state" I don't know the details. So provided that you are above a water mass capable of supporting the ditching idea, the factors mostly influencing the decision are:

Airframe condition
Altitude below you as Pete pointed out and Philip Johnson mentioned in his answer. Too low and you might not have time to deploy parachute.
Sea state
Time of day. You might want to touch water at a lower speed if you can't see it.
Position of allied forces and/or shore. Surviving the crash is one thing; being rescued a whole other.


How do we calculate top of descent (TOD) in flight?

Any approximate method is going to vary for different types of plane, depending on their speed, altitude and descent rate, but here's how I figure it for my Cessna 172.

I know I'm traveling around 2NM a minute (actually a little slower), and I like to descend around 500 fpm.

So if I have to drop 5,000 feet to pattern altitude, the TOD is 10 minutes out (5,000 feet / 500 fpm).   At 2NM a minute, that is 20 miles out.

So if I have my GPS / DME set to my destination airport, I am looking for both ETE: 10 min, and also Dist: 20 miles, then I start my descent.

Its approximate, but its pretty close for planning purposes.
Its always just:

[Altitude Drop] / 500 = Minutes
Minutes * 2 = Miles


Pre-50's, how was electricity generated without using an Integrated Drive Generator?

Inverters, it would appear, were not uncommon. I get the feeling that the quality of the (unregulated) AC from alternators was insufficient for instrument applications, and was primarily used for less sensitive systems. For more stable AC, it appears that the inverters were used.
B-17G

AC System
Alternating current for the autosyn instruments, drift
meter, radio compass, and warning signals transformer is furnished by
either of 2 inverters, one of which is a standby for the other. One
inverter is under the pilot's seat and the other under the copilot's
seat. A single-pole, double-throw switch on the pilot's control panel
controls the DC power to the inverters and selects the inverter to be
used. In the "NORMAL" position the left-hand inverter is on and in the
"ALTERNATE" position the right-hand inverter is on. Source

Anecdotes on PPRUNE also seem to offer support for this.

B-47 Stratojet
Finally, a decent source. Two (unregualted) AC alternators for 'windscreen deicing and some radar equipment', with 2+1 spare single-phase inverters for other AC users.

KC-97 Stratostanker
Has 6 generator dials, and 4 inverters on the flight engineer's station, looking at a panel diagram and the bottom right of this photo. That being said, there are two switches labelled alternators on the AC section of the panel. They only seem to offer "NESA Bus" (B-47 manual seems to imply this is for window deicing) or Bus No. 2, depending on how the right switch is set. The left switch is for the voltmeter/ammeter dials.

Credits to brewbooks on Flickr


Which was the first pressurized aircraft?

The history section of the cabin pressurization Wikipedia article names a few based on the feat:

  The aircraft that pioneered pressurized cabin systems include:

  Packard-Le Père LUSAC-11, (1920, a modified French design, not actually pressurized but with an enclosed, oxygen enriched cockpit)
  Engineering Division USD-9A, a modified Airco DH.9A (1921 - the first aircraft to fly with the addition of a pressurized cockpit module)
  Junkers Ju 49 (1931 - a German experimental aircraft purpose-built to test the concept of cabin pressurization)
  Farman F.1000 (1932 - a French record breaking pressurized cockpit, experimental aircraft)
  Chizhevski BOK-1 (1936 - a Russian experimental aircraft)
  Lockheed XC-35 (1937 - an American pressurized aircraft. Rather than a pressure capsule enclosing the cockpit, the monocoque fuselage skin was the pressure vessel.)
  Renard R.35 (1938 - the first pressurized piston airliner, which crashed on first flight)
  Boeing 307 (1938 - the first pressurized airliner to enter commercial service)
  Lockheed Constellation (1943 - the first pressurized airliner in wide service)
  Avro Tudor (1946 - first British pressurized airliner)
  de Havilland Comet (British, Comet 1 1949 - the first jetliner, Comet 4 1958 - resolving the Comet 1 problems)
  Tupolev Tu-144 and Concorde (1968 USSR and 1969 Anglo-French respectively - first to operate at very high altitude)
  SyberJet SJ30 (2005) First civilian business jet to certify 12.0 psi pressurization system allowing for a sea level cabin at 41,000 ft (12,000 m).

If it is the whole plane and not just the cockpit, then we're looking at the Lockheed XC-35, or the Junkers Ju 49 (whose purpose was to investigate the techniques of cabin pressurization).

For the first in service, then it's the Boeing 307 Stratoliner.

XC-35 (top) and the modified enclosed cockpit of the USD-9A.


What is it exactly about flying a Flyboard across the English channel that made Zapata's thighs burn?

He's using the angle of his legs to control the attitude of the platform (and as a result, the direction he's flying in). So he can't take a relaxed pose, he's standing with his knees slightly bent the whole time.


What are these holes in my Cessna 172, just in front of the elevator?

Those are called "Lightening Holes". The name refers to the weight reduction brought about by removing part of the material—lightening—and should not be confused with anything to do with electrical discharge—lightning.

From the FAA's AMT Airframe Handbook, in Chapter 4, page 4-82:

  Lightening holes are cut in rib sections, fuselage frames, and other
  structural parts to decrease weight. To avoid weakening the member by
  removal of the material, flanges are often pressed around the holes to
  strengthen the area from which the material was removed.

The particular part depicted in your photo is the left hand rear spar assembly for the horizontal stabilizer, No. 32 in this figure from the 1975 Cessna 172 Illustrated Parts Catalogue (IPC):

As you can see, these lightening holes are present throughout much of the spar and rib structures in the horizontal stabilizer, as well as the vertical stabilizer, wings, and fuselage.

In addition to the gains in weight reduction, lightening holes also serve as openings to allow the routing of electrical wiring, control cables, hydraulic tubing, and other system components. If you look at the same location on the right side of the horizontal stabilizer, you should see the elevator jack screw passing through one of the lightening holes, in the location marked "C" in the Cessna IPC figure above.


Why do airports have directional runways instead of a large area to operate in any direction?

The typical World War II "A" runway shape solves this issue, without covering a huge amount of area with concrete, etc. Even so, that configuration has fallen out of use in modern airports.

Ultimately, this is a solution to a problem that doesn't really exist and a problem which has a more efficient solution that was already widely used.

With respect to your particular question - to some degree, this is exactly how original grass fields were treated. But no matter how convenient, there's always a need for consistency and predictability and you can see how that has developed to what we have now. Taxiing a heavy airliner isn't a trivial task - doing so with no markings or defined route sounds terrifying.

Additional practical issues of your large slab of concrete vs. a defined runway:

No ILS
No runway lighting
No runway markings
No threshold, no touchdown markers
Far more difficult to precisely define runway length
Very very difficult to accurately describe a particular location and route

To be honest, the list goes on and on and I'd struggle to imagine commercial ops being able to operate like this safely and efficiently.


What kind of aircraft are currently being used by Boulder County to fight wildfires?

It's a McDonnell Douglas MD-87, specifically one from Erickson Aero Tanker.

Source: eatanker.com


Is IAS without instrument error the same as CAS?

Even without instrument error, IAS does not equal CAS. This because there are two kinds of errors that make up the difference between Indicated Airspeed (IAS) and Calibrated Airspeed (CAS)

Installation error
Instrument error

Installation error is basically a pressure error. Airspeed measurement is a measure of dynamic pressure of the undisturbed airflow. When the pitot tube is not placed directly into undisturbed airflow the IAS will not equal the CAS. Another source of installation error are leaks in the pitot system.

Instrument error is the error introduced by ASI itself by transforming the pressure to a speed indication. For example calibration errors of the pressure sensor or excessive friction in the mechanical drive system of the dial fall into this category.

The POH in your example assumes no Instrument error, but is corrected for installation error. An implicit assumption is made that there are no leaks in the system, so the POH corrects for airflow disturbances. That is why some aircraft have different tables for different configurations; the configurations affect the airflow around the pitot tube.

In aircraft equipped with electronic Air Data Computers (ADC's) the installation error is sometimes automatically corrected by making use of angle of attack sensors, electronic configuration information and lookup tables.


Difference between Flight path and Route

Your route of flight is what you plan, planned, or are planning to fly. Your flight path is what you are actually flying or will be flying based on your current track, heading, speed, and attitude. They can be one in the same.


Can you identify this scrap cockpit section I found in a scrapyard?

Going by the cockpit glazing, I'd say that's a Hawker Siddeley HS.748:


How can a computer model yield two possible flight paths of MH370 in South Indian Ocean?

how they can come up with such specific paths?

Diagrams in news organisations graphics published in March and April 2014 vary widely in what they show and appear to be artistic impressions. These should not be relied on in any way.

To calculate a variety of likely flight paths, it seems Inmarsat engineers, and other parties to the official investigation, used a number of sets of information including but not limited to:

satellite communication timings giving distances from satellite.
satellite communications frequency variations giving relative motions.
knowledge of variations in satellite orbit.
knowledge of variations in satellite temperatures (daylight exposure etc)
knowledge about signal processing timings in various equipment.
characteristics of the aircraft (load, fuel consumption rates, etc)
autopilot modes of operation (route, heading, track. magnetic, true, ...)
etc.

The analysis was improved and refined over time, resulting in newer estimates of the flight path and final coordinates.

Other independent groups of people have published their own analyses which come to broadly similar conclusions. E.g. the self-titled "Independent Group" associated with Duncan Steel

Inmarsat paper, October 7 2014.

A paper "The Search for MH370" published in the Journal of Navigation by Ashton et al. (2014). describes in some detail how the Inmarsat engineers used satellite data to determine probable flight paths for the aircraft.

ATSB report. August 18 2014

The Australian Transport Safety Bureau released a revised version of their June 26 report.

ATSB report. June 26 2014

The Australian Transport Safety Bureau release a 54-page report "MH370 - Definition of
Underwater Search Areas" which goes into greater detail than any prior official report and shows much more of the calculations that were performed on the Burst Frequency Offsets to calculate probable final position of MH370.

In particular the appendices describe some  equations that were used.

A small extract from the report

Raw Satellite Data. May 27 2014

The raw satellite data was made available on 27/5/2014 in response to requests from relatives of the passengers. This shows burst timing offsets (BTO) and Burst Frequency Offsets (BFO) for communications between the Inmarsat ground station and MH370.

ATSB document. May 26 2014.

The Australian ATSB released a factsheet that outlines what is known and reiterates the general description of how the tracks were calculated:

  By
  taking the maximum speed of the aircraft into account, the rings can be reduced in length to arcs – there
  are some areas of the rings it simply could not have reached.

  There are a large number of speeds and headings that can be
  consistent with a BFO recording. These are limited, however, by the operational constraints of the aircraft.
  Candidate paths of different speeds were created which met the BTO ring location/time constraints and
  the predicted BFO values of these paths have been compared with the recorded values. The better the
  match, the higher the probability that the path was close to that of MH370.

Release of raw data from satellites. May 27th 2014

On May 21st 2014 CNN reported that the satellite data and description of analysis would be published. No date has been specified.

  "In line with our commitment towards greater transparency, all parties are working for the release of the data communication logs and the technical description of the analysis for public consumption," Inmarsat and the Malaysian aviation officials said in a joint statement.

Inmarsat Statement. March 24 2014

On March 24th 2014, Inmarsat stated that a new analysis of the records of satellite handshakes with MH370 were able to use doppler effects in the signals together with an analysis of similar satellite handshake data from other Malaysian 777s to determine that MH370 flew into the Indian Ocean and ruled out flight paths to the previously described northern corridor.

From INFORMATION PROVIDED TO MH370 INVESTIGATION BY UK AIR ACCIDENTS INVESTIGATION BRANCH (AAIB)
25/03/14

Malaysian Defence Minister statement. March 21 2014.

On March 21st, a little light was shed on this process by a statement attributed by New Straights Times to Malaysian Defence Minister and acting Transport Minister Datuk Seri Hishammuddin Hussein.

  "The investigations team received the complete raw Inmarsat satellite data, which included the six handshakes at approximately 3 pm on Wednesday, March 12."

  "This type of data is not normally used in investigations of this sort.
  It is only because we have so little other information to go on in this difficult and unprecedented situation that the data is being used.

  "Upon receiving the raw data, the Malaysian authorities immediately discussed with the US team how this information might be used. The US team and the investigations team then sent the data to the US, where further processing was needed before it could be used.

  "Initial results were received on Thursday, March 13 at approximately 1.30 pm, but it was agreed by the US team and the investigations team that further refinement was needed, so the data was again sent back to the US.

  "The results were received at approximately 2.30 pm on Friday, March 14 and presented to the investigations team at a high-level meeting at 9 pm on Friday.
  The UK AAIB, who had also been processing this data independently, presented their results - which concurred with ours and those of the US team – at that meeting.

  "The Prime Minister was briefed on this satellite information at 8 am Saturday, March 15 and publicly announced it at the press conference at Saturday lunchtime.

(my emphasis)

Obviously the above does not describe the actual calculations involved. However it does confirm that the satellite data had six handshakes (presumably at hourly intervals up to 08:11).

Early speculation

The graphic below, illustrates one idea for how these track might have been deduced. It is a result of speculation rather than a reporting of information actually provided by the people who made the calculation.

The graphic suggests that the NTSB calculated possible paths based on data that is not public and that the NTSB were able to assign probabilities to those paths. As far as I know, neither Inmarsat, the NTSB nor the Australian government (or it's agencies) have made public the data or method of calculating these tracks.

The graphic below suggests several Inmarsat pings were used (the example shows 01:11, 02:11, 04:11, 05:11, 06:11, 07:11 and 08:11 but these are probably speculation).

So far as is publicly known, there was no ping at 09:11 or later which suggests the flight ended between 08:11 and 09:11. This is broadly consistent with maximum fuel range of the aircraft. The labelled NTSB solutions suggest that NTSB calculated that no other constant speed (and heading?) tracks fit the data.

source Scott Henderson

which says ...

  For a constant speed track, distance between ping arc intersections will be equal.

  NTSB solutions are based on constant speed straight track. Curve in track shown due to map projection

A later version of this graphic adds a disclaimer saying that the tracks and zones are not accurate and are symbolic only.

We do know that NTSB sent staff to Malaysia to assist in the search. We know that Inmarsat provided data to the investigating teams.


How should I interpret the difference in flight direction (azimuth) for great circle and rhumb line?

I have no idea where the image comes from, but it seems that you have spotted an inconsistency/copy-paste typo.

Let's remember that the heading is always measured w.r.t. the north, increases in a cloclwise fashion and indicated the direction the aircraft is flying to, as shown in the following figure:

(Image Source: www.allstar.fiu.edu)

On the Rhumb line both East and West directions are shown both with arrows ($\rightarrow \;\; \leftarrow$) and with the initial headings ($90^o \;\; 270^o$)

On the Great Circle lines only the westerly arrows appear and only the starting headings from the West are correct. These seems to have been copied to the East side, but they should have also been augmented by $180^o$, i.e. as you were expecting, you should have $330^o$ for the northern hemisphere (in lieu of the $150^o$) and $210^o$ instead of $30^o$ for the southern.


How can I calculate the thrust of a fan given the diameter of the blade?

I checked out your original post, and the Quora post referenced in it. The thing is that what is mentioned there is simple impulse dynamics: there is a magic disk with no drag that accelerates air going through it. It's a theory that works if you realise the limitations, allows for quick ROM estimations, and can provide even more useful info when some drag effects are included in the form of propeller/rotor efficiency. The Quora post is not incorrect, but it is a simplification and it is valid for a different scale.

For a magic disk, all you need to know is the disk area, it does not even need to have a mounting axis. For a real propeller/fan that is not optimised yet, the following parameters need to be considered:

Blade radius, resulting in the disk area.
Rotor RPM, together with the blade radius resulting in tip velocity.
Blade pitch
Blade chord
Blade profile
Number of blades

Between your application and the Quora helicopter disk, there are the following differences that need to be catered for:

Your rotor is small. Reynolds effects start playing a big role here, with a much thicker boundary layer. Departs further from the impulse theory than an average helicopter rotor: increases power demand.
Your rotor is ducted: reduces power demand by about 35% for small rotors, see figure below.
Your rotor is a fan: increases power demand. Every added blade requires proportionally more power for a an increase in thrust that gets smaller with every blade.
Your rotor has difficulty bringing the air in. A curved duct restricts incoming air flow, increasing power demand and putting a cap on maximum thrust.

So we need to use data from small scale rotor research. Here is a masters thesis researching just that, unfortunately with an underpowered motor so the results are only valid for low Mach numbers. If we look at the highest Mach number in the graph and compare data points for Thrust = Lift, we can see an increase in $C_T$ (is a measure for thrust) of 0.047/0.035 = 35%.

$C_T$ is defined here with reference to the ducted fan wetted area, and it is not very clear which units are used. There is a graph of thrust force vs. rotor rpm:

6000 rpm with a 9.5" rotor equates to a tip Mach of 0.22. Propellers can run with a tip speed of up to 0.75 Mach before compressibility effects occur, that would be 20,000 rpm for this configuration. Extrapolating the curve to 20,000 rpm would result in about the 15 - 20 N mentioned in the OP.

It's a 3-blade rotor. Thrust can be further increased by increasing blade pitch and increasing number of blades, each increase requires an increase in power as well. Unfortunately the research does not mention power required for each thrust config found, but:

Appendix A has some provisional power curves for other rotors used in the project. It also mentions the use of a gearbox to increase rotor rpm, something OP may wish to consider as well.
A table with a motor trade study used in earlier research is included, outlined below.


Can time spent in consumer flight simulators increase the safety of flying light sports aircraft for licensed pilots?

Perhaps yes, but it's not easy to qualify objectively.

Simulating a light airplane may require a different approach in some areas, but it's not inherently difficult compared to 'heavy' ones.

However, the truth is, nobody cares that much, so there is much less investment in such simulators. A decent FTD (flight training device, something a step lower than what is legally called a 'simulator' (FFS)) will cost easily several times more than an ultralight, while the risk benefit is arguably lower (compared to real flight).

Secondly, type-rated simulators are rarity even on the 'proper' GA market; typically FTDs are 'generics' that aim to simulate a representative 'class' of aircraft. This makes fair comparison difficult, especially by real pilots who have most experience on a single/few real types.

Then, there are technical features that are even more important for light (and GA) airplanes than for big ones. One is a good visual system: in real visual flying, you obviously use it more, and having a single monitor stuck in front of you will hamper you more than you might think.

Second is control loading: on light airplanes you get airspeed and trim feedback right at your fingertips. There are no cheap solutions to this. You may argue this is not 'physics', but it actually is, this is all part of a feedback between the airplane and you being the part of control system. Lack or poor quality of these things (which is more than common on the simulators used for light planes) will substantially affect subjective and objective qualification of the flying qualities/handling of the simulator.

There are areas where even expensive FFS suffer. A typical example is ground handling. Or, speaking about 'loss of control', many regimes that result from it, notably stall and spin, are actually difficult to simulate well, and are often not required for certification.

That all said, it's an overstatement to say that simulators are 'useless for preventing accidents'. Flying is more about thinking ahead, planning and situation awareness than any specific piloting skills, and even a game simulator can teach you some of that.


Where are US FIS-B UAT ground facilities located?

The FAA does publish a list of towers but no locations, only a generic coverage map.

However, the towers do broadcast their own location, and some Stratux users have collected that data and turned it into a map.


Besides size, what determines the cost of creating a composite structure for a single engine piston aircraft?

Cost drivers for composite structures:

Weight: Lighter is harder to do and needs more work and more expensive materials.
Surface quality: Either you use lots of filler and several sanding and filling cycles, or you produce a high-quality negative mold, which is a lot of work.
Reproducibility: If you want to produce several identical parts, you need to produce a reusable negative mold. Simple composite structures can be built in a positive technique.

Positive building techniques

You can either use a styrofoam core which you cover with fibers and epoxy (just as Burt Rutan did), or you build a balsa wood core on a simple jig and cover it in fibers and epoxy on both sides to produce a sandwich shell. In both cases you build from the inside out and have to finish the surface with repeated cycles of filling and sanding until you arrive at the desired contour and surface quality. This is a lot of work already, but much simpler than building a negative mold.

Negative building techniques

Here you first produce a core of the desired shape (again much like the styrofoam-epoxy structure above) and use this to produce two casts which will serve as the mold in which to build the eventual structure, or you take a large CNC mill and have it produce the mold from a big block of aluminium (or another suitable material). Now you will build the structure from the outside in, so you achieve the desired surface quality without filling and sanding the final structure, and you can repeat this process to produce several identical pieces until the mold is worn out.

If you add up the material and labor cost of the two techniques, you will find large cost differences which are reflected in the quality of the final parts.


Why don't commercial jet aircraft have a break-apart, parachute escape system?

wouldnt that work for keeping a majority of passenger jets from crashing?

The majority of passenger jets don't crash.

Designing an aircraft like that would incur very substantial weight penalties. The Space Shuttle booster rocket parachutes weight 990kg, each (it needs 3) plus 550 kg for the drogue chute needed to pull out the main canopies. Plus another to pull out the 550kg drogue. Where are you going to put that much nylon?

Then there's regular maintenance of stuff that large and heavy - you will need an entire empty hangar to repack things along with a crew and a crane.

Also consider how you are going to break up a commercial airliner in an orderly manner. It would have to be designed for it and lined with explosives. That's going to be really popular.

Finally, parachutes need time to work. Large parachutes need considerable time. So this whole process only helps if there's a problem in cruise flight, and that's the phase with the lowest accident rate. Parachutes below 1000 feet are just excess weight.

Semi-related Addendum: After Challenger went boom the Space Shuttles were fitted with a crew escape system. It was intended to allow the crew to exit when the craft was under control but unable to reach a survivable landing site. Re-read that carefully: when the craft was under control. The crew exits at reasonable altitudes and the Shuttle crashes under remote control.

Parachutes simply haven't been a viable option for commercial air transportation since the DC-3 era.


How can a pilot deal with a magneto failure?

One of the things the checklist will have you do prior to lining up on the runway in a piston engine aircraft is a magneto check. That serves to verify that both magnetos are in good working order and that the grounding of both magnetos is intact.

Typically, that will involve bringing the engine to some given power setting (most likely expressed in terms of RPM, but I suppose it could be measured in some other way for some engines; manifold pressure, maybe?) while holding position, then turn one magneto off, then back on, then turn the other off, then back on. While doing so, you verify that there is a drop in engine power, and that the drop in power is symmetric (about the same for both magnetos), and of course that the engine keeps running on either magneto alone.

This verifies that both ignition systems (magneto, spark plug, etc.) are working, and that the grounding of the magnetos works as expected. Absent the power drop, you could have a hot magneto, which isn't a huge problem in flight but could be a major headache on the ground.

If a magneto fails in flight, especially in a single you might not even notice initially; there will be a slight reduction of engine power, just like during the magneto check, but the engine will keep humming along on the remaining magneto. That's part of the purpose of having two independent ignition systems: redundancy.

If there is an engine failure in flight, the checklist will likely dictate something like "select best magneto" at one point or another during the restart sequence. Basically, you'd be doing a magneto check in the air, and choosing whichever setting gives you more power. If one magneto has failed outright, this will very likely cause the engine to stop when you select only the bad magneto; you'd then have to select the other (or both) and restart the engine again.

The checklist may or may not specify that you should land as soon as possible after a magneto failure, but if it were me, I'd want to land regardless and have the problem checked out properly. That would mean either just landing and taxiing back to the ramp (if, say, you're in the pattern doing circuits), or diverting and landing (if you're on your way to somewhere). There's always the possibility that whatever caused the first magneto to fail might cause the second to fail as well, and I'd rather be on the ground at the wrong airport than in the air with a non-functional engine.


Did old propeller aircraft begin takeoff off-center to counter p-factor?

Why ask in past tense? The Mü-23 motor glider has a central wheel and would need someone to hold a wingtip during take-off. Sometimes, a different technique is used: The aircraft is parked at a right angle to the (grass) runway, with the wingtip pointing into the intended take-off direction on the ground. When the pilot opens the throttle, he steps on the rudder, causing the aircraft to swerve into the desired direction and rotating into a horizontal attitude thanks to the centrifugal force.

Akaflieg München Mü-23 (picture source)


Why is on-time performance important for commercial flights?

I can think of a few:

Any delay in the flight is a waste of valuable resources- the flight, cabin and ground crew who have to be paid and the aircraft itself, which is not generating any revenue but costing money for the airline. Also, the airline may have to pay for the time the aircraft spends in the airport.
There is an economic cost associated with on-time performance- for example, passengers are more likely to take airlines which have better on-time performance over others.
Another case is that of customers taking connecting flights- again, on-time performance could be the difference here. This means loss of business for the lower performing airline.
For airlines operating multiple trips per day, the delay and the associated costs are cumulative; for example, if the first flight of the day is delayed, it snowballs into the day- requires replanning for the rest of the day in other airports and causes further delays.

For the airline industry, the delays cost billions of dollars every year (1 and 2) and can reduce the operating revenues by a few percentage points (3). The table below, taken from the NEXTOR report on Total Delay Impact Study shows the cost to US airlines due to delays.

As can be seen, the the costs due to delay to airlines are quite high.


If the efficiency of a turbofan engine is 35%, where does the rest of the fuel energy go?

There are a couple of sources of loss throughout the process, as indicated in the figure from an old paper format uni book. I've had to translate the labelling, open to suggestions there. The percentages are valid for a high bypass turbofan manufactured in the late 80s.

The total energy input starts with the fuel flow: chemical energy per second.
Combustion converts the chemical energy into a heat flow pretty successfully, with about 1% lost in incomplete combustion. This takes place in the combustion chamber.
The turbine extracts mechanical energy from the heat flow, and uses a portion of it to power the compressor. The thermodynamic efficiency of the Carnot cycle determines the resulting power fraction. I've labelled the resulting net mechanical power as Gas Power which sounds a bit dicey. This Gas Power can be converted into shaft power and/or into jet power, depending on the type of turbine engine.

Note that the thermodynamic efficiency depends on the inflow speed of the air into the combustion chamber: it is decelerated and compressed in the intake, allowing for higher pressure ratios which result in higher efficiencies.
We now need to utilise the Gas Power to raise the kinetic energy of the medium that is used for propulsion. This increase in kinetic energy (from the reference frame of the aeroplane) is labeled Propulsive Power.

Aero engines can be divided into two major groups:

a. Transformation of available Gas Power into shaft power, delivering mechanical energy which can drive a propeller or rotor, which then increases the kinetic energy of a mass flow of surrounding air - a turboshaft.
b. Direct transformation of available Gas Power into kinetic energy by expansion in a nozzle - a turbojet.

The principal difference between the two is that in a. the mass flow  delivering the propulsion is larger than the mass flow through the turbine, while in b. the mass flow through the turbine is equal to the propulsion mass flow. Since thrust T = $\dot{m} \cdot \Delta V$, this means that at a given thrust and entry velocity, the exhaust velocity of a. must be lower than of b. Note that both the turboprop and the turbofan are a mix of a. and b. since a portion of the turbine mass flow is expanded for jet propulsion.

Converting Gas Power into Propulsion Power cannot take place isentropically (loss free): in a turbofan about 5% is lost into heat flow, less in a turboprop.
The propulsive power is the power transferred to the medium used for propulsion (air or combustion gas). The Propelling Power is the power transferred to the aeroplane. There are efficiency losses in this process as well: the medium exits the propulsion assembly at a higher velocity than the airspeed of the aeroplane, and therefore has a certain absolute velocity (relative to earth). The corresponding kinetic energy flow must be considered as a loss. Of course, the outflow velocity must be greater than the airspeed in order to generate thrust.

This power transformation is therefore also associated with an efficiency factor, $\eta$ propulsion. It costs power to drive those fan blades, which have induced drag and profile drag just like a wing does.

When using these definitions, we can see that an aeroplane on the runway, just before take-off, with the brakes applied and the throttle fully open, has:

Maximum propulsive power since the airflow has maximum $\Delta V$. As computed in this answer.
Zero propelling power, since none of the propulsive power has been transferred to the aeroplane yet. All propulsive power is transformed into kinetic energy of the gas flow.


What means of navigation did commercial Soviet airplanes use in the 50s-90s?

The Soviet Union had GLONASS for aviation civilian use in the latter part of the requested 50s-90s period.

  From 1982 to April 1991, the Soviet Union successfully launched a total of 43 GLONASS-related satellites plus five test satellites.

  (...) For a long time, the USA could not find out the nature of those "objects". The Telegraph Agency of the Soviet Union (TASS) covered the launch, describing GLONASS as a system "created to determine positioning of civil aviation aircraft, navy transport and fishing-boats of the Soviet Union".

and

  (...) the Ilyushin Design Bureau learned much from the Il-86 program and in 1988 developed the Il-96, with the 80-400-type computer integrating triple INS, Omega and GLONASS displays in the navigation HUD for Cat IIIA performance (aviationtoday.com).

VOR/DME, ADF, inertial, and Doppler navigation were all present on Soviet airliners in varying combinations based on the mission/plane. They also had computerized astro-navigation (not sure if a Western equivalent existed for the civil aviation -- the computerized part):

  [C]ommercial transports (...) were able to hold the large central TsNV navigation computer complex (multiple boxes with different sub-functions), although the TsNV was too large for smaller aircraft. The complex’s main unit was the BTs-63A astro-orienter, which included an auto sextant, course indicator and computer. Inputs by the navigator to the digital navigation computer (TsNV) were through a PUISH keyboard, part of the control-indicator unit (aviationtoday.com).

Navigators were part of the crew (primarily for long-haul), but it took longer for the navigator position to become redundant compared to the West. Longer not because of a technological deficit, but because of stronger unions and job creation.

Let's look at an example, the Ilyushin Il-62 (1967—), it's long range and it matches the period.

(wikipedia.org) Part of the navigator's panel showing 1) ADF and 2) DME.

Above you see ADF and DME instruments. And much like the attitude indicators, they're the same but with a different look. A typical Soviet VOR (CDI) instrument is shown below (they also used kilometers for the DME):

(wikimedia.org) CDI instrument for VOR on the Ilyushin Il-62.

  Its avionics include a

  Polyot-1 automatic flight control system -- a "super autopilot," able to be programmed with a set route which it can fly without human intervention but under constant flight crew monitoring
  ICAO Cat. 1 approaches standard, Cat. 2 optional
  Doppler navigational radar...
  replaced by triplex INSS (Inertial Navigation System Sets) on Il-62M after 1978
  and by GPS (Global Positioning System) navigation sets on many aircraft after 1991
  triple VHF and HF flightdeck radios
  automatic direction finders
  Soviet and Western instrument landing system receivers
  [VHF] omnidirectional radio range and radio beacon receivers.

(Edited to be a list for easier reading.)

I also found en route charts for the Soviet Union showing NDB and VOR stations (but I couldn't confirm the date).

The first plane to have an FMC as it is known today as default equipment, was the Boeing 767 (1981), a few years later (1988) the Ilyushin Il-96 followed in the glass cockpit trend:

  It features (...) a glass cockpit, and a fly-by-wire control system.

(airliners.net)

Addendum:

I tried to look for specific dates, the best I got to was an American 1974 report, 'CIVIL AVIATION OF THE USSR', by the Foreign Technology Division, Wright-Patterson Air Force Base, Ohio, which noted:

  More than 90 airports were reconstructed or newly built, lines were equipped with modern means of air navigation and radio equipment.

Also since the USSR joined ICAO in 1970 (nytimes.com), it's safe to assume at least since then any radio-based navigation technology that's been in use eventually met the standards of international civil aviation.


Does the FAA advise or require pilots to wear eyewear designed to protect them from lasers?

I'm not aware of FAA (or any other regulatory body) recommending protective eyewear for lasers. FAA safety Advisory doesn't include them. There are a couple of problems with using protective eyewear for lasers:

The eyewear is usually wavelength sensitive; The pilot has to wear the correct eyewear that blocks the incoming laser beam; he/she should know the wavelength of incoming laser.
The protective eyewear filters (atleast most) of the incoming light in that wavelength. This may affect the normal sight of the flight crew.

Due to these reasons, the regulatory authorities are more concerned with procedural changes that protective wear. From Boeing's protection against lasers:

  ... however, airlines should consider the drawbacks that are associated with them. Filtering light reduces the total amount of light entering the eye, which can adversely affect normal viewing, ... . In addition, filtering green light can remove some green flight symbology on flight deck displays and change the appearance of some of the other colors used. As a result, protective glasses should be used with care.