How do you calculate minimum runway lengths for Part 135 operations using the 60% rule?

Required runway length for landing
The minimum runway length required for landing under Part 135 operations is, believe it or not, the same as Part 91: You need to be able to land and stop within the available runway length specified in the AFM.   This is what you use when you are getting ready to land.
That being said, since you reference the "60%/80% rules", there is a more stringent requirement that is required as part of your preflight planning and specified in 14 CFR 135.385
60% Rule for Large Turbine Transport Category Airplanes
This rule is specified in 14 CFR 135.385(b), and says (in part):

no person operating a turbine engine powered large transport category airplane may take off that airplane unless its weight on arrival ... would allow a full stop landing at the intended destination airport within 60 percent of the effective length of each runway

So to follow the regulation by the letter, you need to take 60% of the runway length and compare it to your actual landing distance.
Example
We want to land on a 6,000 ft. runway, so our max allowable landing distance is 3,600 ft.:
$$6,000ft\times60\%=3,600ft$$
Determining minimum runway length
Sometimes pilots prefer to ask the question in a different way, and ask "what is the minimum runway distance needed for the current conditions" instead of "what can my maximum landing distance be.  To calculate this, we simply re-arrange our formula above like this:
$$Minimum~Runway=\frac{Actual~Landing~Distance}{60\%}$$
If our actual landing distance is 3,000 ft. then we would need a minimum field length of 5,000 ft.:
$$\frac{3,000ft}{60\%}=5,000ft$$
80% Rule
The 80% rule specified in 14 CFR 135.385(f) works exactly the same way, but can only be used by an "An eligible on-demand operator" if approved in accordance with their Operations Specifications (A057 and C049) and the procedures listed in their Flight Operations Manual.
You would then replace the 60% with 80% in the above calculations.
Wet Runways
14 CFR 135.385(d) says:

(d) Unless, based on a showing of actual operating landing techniques on wet runways, a shorter landing distance (but never less than that required by paragraph (b) of this section) has been approved for a specific type and model airplane and included in the Airplane Flight Manual, no person may take off a turbojet airplane when the appropriate weather reports or forecasts, or any combination of them, indicate that the runways at the destination airport may be wet or slippery at the estimated time of arrival unless the effective runway length at the destination airport is at least 115 percent of the runway length required under paragraph (b) of this section.

So basically, you use the information from your AFM for wet runway landing distance, or if it isn't provided (since it isn't required), you do the same calculation that you did before but include an additional 15%.
Example:
Taking the example from the 60% rule and assuming that it is wet, we have a max landing distance of 3,130 ft.:
$$\frac{6,000ft\times60\%}{115\%}=3,130ft$$
Minimum Runway Length When Wet
The minimum runway distance with a 3,000 ft. actual landing distance would be 5,750 ft.:
$$\frac{3,000 ft\times115\%}{60\%}=5,750ft$$


NOTAM - What means "no shoulders along taxiways" in German?

The NOTAM you copy doesn't mention taxiway shoulders anywhere. It says there is work going on on the shoulders of the runway and apron, and that a taxiway is closed.

As to taxiways not having shoulders, quite possible. The hard shoulder is the area outside the marked road surface, this can sometimes be extremely narrow.


Those stall speeds are derived for specific conditions.  In the case of that POH those speeds assume level unaccelerated flight, 2550 lbs gross weight, standard atmosphere and no wind.  They are given as a speed rather than raw AoA because most non-aerobatic small airplanes lack AoA indications in the cockpit, while all have airspeed indicators.  A non-aerobatic airplane also spends most of its time in the part of the flight envelope where the assumptions needed to list a stall speed tend to be valid.

The stipulation of level flight means the relative wind is fixed, thus the AoA depends only on the pitch attitude above the horizon.  For an given weight there is a relation of pitch attitude required to maintain level flight for a given airspeed.  Given these specific stipulations, you can determine the airspeed that results in the critical AoA being exceeded.

If any of the criteria listed above are not true, then those published stall speeds are not meaningful to you.  You can stall at any attitude and at any airspeed.

To see the true relation between airspeed and stalling you need to consult a Vg diagram.

The curved lines starting at 0 MPH and 0 load factor represent the stall speed for a given load factor.  The stall speed listed in PoH you quote is specifically the point noted "Normal stall speed" on this chart (this chart isn't for the same airplane, so the numbers will differ).


Must a CFII be instrument current to provide instrument training?

The requirements for providing instrument instruction are in 14 CFR 61.195(c) and they don't mention currency at all. There are also various FAA legal interpretations on whether or not CFIs (not CFIIs) require an instrument rating to provide instrument training (see this question), and what instrument training requires a CFII in the first place (see this question) and none of them mention currency either.

So no, there is no requirement for a CFII to be instrument current when providing instrument training.

Having said that, 61.65(d)(2)(ii) requires instrument students to do a cross-country under IFR with an instructor. An instructor who isn't instrument current couldn't provide that specific training flight, although obviously the student could use a different instructor. And many CFIIs like to take their instrument students into IMC to let them experience how different it is from being under the hood.

All in all, it's in a CFII's best interests to remain instrument current but it isn't required.


What is the procedure for an air traffic controller after a major crash or incident occurs on their watch?

Most units today will have some sort of CISM procedure.

Critical Incident Stress Management (CISM) is the structured assistance for a normal reaction to an abnormal event.
CISM methods are secondary preventive measures which consist of discussions about the incidents in the form of structured individual and group discussions and help the persons affected regain their ability to apply coping strategies. Most of the time these discussions are performed by colleagues who have qualified in CISM programmes (the so-called CISM peer diffusers or CISM peers) or by Mental Health Professionals (MHPs) who are qualified CISM experts. None of the CISM techniques can, or should be, regarded as psycho-therapeutic measures.

Read more at skybrary: https://www.skybrary.aero/index.php/Critical_Incident_Stress_Management_in_ATM


Regulatory Documents To Carry Medical Kits and Defibrillators On-Board

I can’t comment on ICAO requirements, but for domestic and Flag Operations in the US, §121.801 - §121.805 and §121 Appendix A cover the requirements for emergency medical equipment, including electronic defibrillators, to be onboard scheduled air carrier aircraft and specify training requirements for flight crew members on their use.


Where is the best place to perform a run-up at a busy airport?

In my humble opinion it is best to ask the FBO for their practices or do it at the ramp with precautions as not to hurt or disturb anyone or anything.

On the Taxi way you might run into difficulties returning to the ramp in case something does not look or perform right during run-up. When in dout I ask Ground for advice.


How can a large passenger aircraft's owner remain unknown?

Every country handles aircraft registration differently (but generally similar). Im sure Boeing could tell you who they originally delivered the airframe to but if it was sold from there it could legally go anywhere and would only be subject to local registration legislation.

Here in the US you can look up aircraft owners by N number but not all countries may keep a record like that and as far as I know there is no global aircraft registry.

  it is still impossible to find actual aircraft's owner in a matter of minutes

Knowing who the owner is and finding the owner are two very different things.

According to this article

  Several aviation databases list the Boeings -- identified by their
  call signs TF-ARN, TF-ARH, TF-ARM -- as belonging to leasing firm Air
  Atlanta Icelandic, but that company says it sold them in 2008.

  Since then, the aircraft appear to have changed hands several times.

  Malaysia Airports says it's entitled to sell the Boeings under the
  country's civil aviation regulations if no owner comes forward.

So it seems they do know who owned them at some point (most likely the last people to put readable registration numbers on them).


How have deep-seated cultural human factors (particularly in east Asia) in the cockpit been successfully managed in the past 20 years?

The commercial aviation world today emphasizes crew resource management (CRM) as an integral part of flying. The premise of effective CRM lies in the principle that any member of the flight crew, whether it's the captain or the first officer, is able to, and should express honest and valid concerns during the flight without worrying about being marginalized or ignored.

Before I start, I would like to point out that Asian airlines are not the only ones to exhibit poor crew management in the past. KLM 4805 (Tenerife), Eastern 401 (crew gets distracted on approach trying to replace a light bulb), and more recently, Air France 447 serve as some examples.

I think the reason why crew management-related accidents in Asia come under the spotlight much more than others (I still hear Asiana 214 jokes all the time, and it's getting really old...) is the fact that the very nature of East Asian culture counters the basic premise of effective CRM — that regardless of position or status in the cockpit, each crew member has a responsibility and a right to speak up. Instead, everybody has a clear-cut hierarchical position roughly based on age. Therefore, whereas accidents in the West are viewed as one-off mistakes made by individuals in an individual case, accidents in the East are viewed more as a natural consequence of the area's culture.

Now, Asian aviation has changed a lot since the '80s. CRM training is a big thing in the industry (just like how the western world has been doing it) and there has been a giant push in the general culture as a whole to create an environment where everyone is heard with equal weight. Change alright, but the roots of old culture remain despite these recent developments, and this is especially true in the corporate environment (including the cockpit). The give-it-to-me-straight-doc cockpit culture in the East still makes it very hard for the FO to speak up and sort of awkward for the captain to allow other crew members to cooperate, even if he or she is willing to make the most use of the crew body.

So, to wrap up my answer to the question, there have been numerous efforts to improve crew management/human factors in the East, but we haven't quite seen the full effects of such changes. Perhaps when the current generation of pilots go (most of them in their '40s and '50s, who were born before the rapid cultural changes in Asia) and the newer, younger generation sets in might we be able to better gage the true effects of changing culture in Asia.

There is no way to summarize this entire subject in a perfectly objective way and there will be people that disagree with some things I've noted. All my above observations were made as a Korean now living in the US. Hopefully my 2 cents help.


Why does a clean configuration lead to the generation of greater wingtip vortices?

I would actually assume the opposite to be true.

Let us assume the vortex intensity and the induced drag are directly correlated. The induced drag coefficient can be expressed as:

$c_{Di}=\frac{c_L^2}{\pi\cdot AR \cdot e}$

$c_L$: Lift coefficient
$AR$: Wing aspect ratio
$e$: The so-called Oswald factor, a number which equals one for elliptic lift distributions. It decreases for distributions that deviate from the elliptic one.

Most wing designs aim to achieve an elliptic-like lift distribution in order to minimise induced drag in clean configuration.

As flaps, spoilers, air-breaks and so on are deployed the lift distribution will deviate substantially from the elliptic one (see diagram), hence reducing the $e$ factor and increasing the induced drag. If the first assumption still holds, an increase in induced drag will have been caused by an increase in vortex intensity.

Additionally, significantly higher lift coefficients can be achieved with deployed high-lift devices, which also contribute to increase vortex intensity.


What are the slides that ATCs use for tracking departures and arrivals?

Yes they are called flight progress strips or simply strips. They are still in use, though they tend to be replaced more and more by the electronic strip or e-strip.

They are also used by en-route controllers (not only terminal as you mentioned). From my experience from Athens ACC, PALLAS supports e-strips, but there is also a printer that prints them in some intervals (I don't remember what triggers the print). Note that some time ago, during the procedural control era, those were manually completed by the ATCOs. I guess they are still manually completed in TMAs and ACCs that use procedural control as primary method and lack RADAR service.


Why does Class D overlap class B around SeaTac? ...and other Seattle Bravo airspace strangeness

This is a great question. For those who are unfamiliar, and in areas where airspace is complex, it’s sometimes useful to look at the VFR Flyway Chart. This is the one on the back of FAA Terminal Area Charts.

The dashed blue outlines surround the crazy cutouts that are Seattle’s Class D airspaces.
Why does KBFI stick into the KSEA Class B?
Class D airports, or at least those that don’t exist entirely within more restrictive airspace, will always have a ceiling. This is because there will be sections that are not contained within the Class B (or C) areas. For those areas, we need to know how high the Class D airspace goes.
If there is Class B and Class D airspace in the same place, which is it?
This one is in the AIM, 3-1-3:

Hierarchy of Overlapping Airspace Designations
a. When overlapping airspace designations apply to the same airspace, the operating rules associated with the more restrictive airspace designation apply.

So, if you’re over the I-90 bridge at 1900 feet, you’re in KBFI Class D. If you’re at 2100 feet, you’re in KSEA Class B.
Why does KSEA have weird class D chunks?
This one is easier - because Class B doesn’t always go to the surface (only at the core), but there is still a need to filter out traffic from the immediate airport environs. Because two-way communication is required, pilots will need to talk to the tower before getting too close (~5SM) to the airport.
Another factor is that Class D centers on the airport; Class B is centered on the SEA VOR, and they are not coincident. This is so that the rings could (when it was circular) be defined with DME.


Has there ever been a sideways H-tail on an airplane?

Most of the initial aircraft made by Wright brothers had the twin horizontal stabilizer setting. However, the elevators in these cases were set in the front, rather than back, as is the norm now.

By Wright brothers - OhioLINK Digital Media Center, Public Domain, Link

Quite a few of the early aircraft had a 'box' like configuration, notably the Santos-Dumont 14-bis, which made the first public powered flight. Again, though the pitch control was through the box like structure, it was more of a canard than a horizontal stabilizer.

Santos-Dumont 14-bis; image from Wikipedia

One of the earliest aircraft with a 'proper' twin horizontal (as well as vertical) stabilizer was the aptly named Bristol Boxkite

Bristol Boxkite; By Hpeterswald - Own work, CC BY-SA 3.0, Link

Another good example is its predecessor, the Farman III, which had two horizontal stabilizers and a single vertical tail right in the middle, forming a perfect sideways 'H'.

Farman III; By C.C. Pierce & Co. - http://digitallibrary.usc.edu/cdm/ref/collection/p15799coll65/id/12574, Public Domain, Link

You can see that most of these are early aircraft, which had structural limitations. As the aircraft design matured, the 'conventional' layout became the norm as a single stabilizer assembly can be used to achieve the necessary pitch control.


What is the difference between AIM, AIP and AIS in the US?

From the beginning section of the Aeronautical Information Manual (AIM).

This manual is designed to provide the aviation community with basic flight information and ATC procedures for use in the National Airspace System (NAS) of the United States. An international version called the Aeronautical Information Publication contains parallel information, as well as specific information on the international airports for use by the international community.
This manual contains the fundamentals required in order to fly in the United States NAS. It also contains items of interest to pilots concerning health and medical facts, factors affecting flight safety, a pilot/controller glossary of terms used in the ATC System, and information on safety, accident, and hazard reporting.

Aeronautical Information Publication front section

2.1 The AIP is prepared in accordance with the Standards and Recommended Practices (SARP) of Annex 15 to the Convention on International Civil Aviation and the Aeronautical Information Services Manual (ICAO Doc 8126). Charts contained in the AIP are produced in accordance with Annex 4 to the Convention on International Civil Aviation and the Aeronautical Chart Manual (ICAO Doc 8697). Differences from ICAO Standards, Recommended Practices and Procedures are given in subsection GEN 1.7.

Aeronautical Information Services

Is the authoritative government source for collecting, validating,
storing, maintaining, and disseminating aeronautical data for the U.
S. and its territories.
Develops and maintains all public instrument flight procedures and airways.
Serves as the FAA's aeronautical charting authority for the development, publication, and dissemination of aeronautical charts and products to support aviation and to meet demand for increased capacity, efficiency, and predictability in the airspace, routes, and airports of the NAS.


Why is there a disparity in the conversion from runway visual range (RVR) to statute miles?

Some light on the mysteries of conversion...
Types of devices used for RVR measurement
A RVR device is composed of a light source and a light sensor. The light source is an incandescent lamp in a transmissometer, the oldest device, while in the more modern scatter-effect device it is an infrared LED. The sensor can determine RVR in a certain range, with the accuracy varying in the range:

Incandescence: Down to 600 ft by 200 ft increments within 600-3,000 ft, 500 ft above 3,000 ft.

Infrared: Down to 0 ft by 100 ft increments below 800 ft, 200 ft within 800-3,000 ft, and 500 ft above 3,000 ft.

RVR unit conversion
To make RVR ft-m conversion easy, rough equivalences are established:

100 ft = 25 m
200 ft = 50 m
500 ft = 150 m

Visibility unit conversion
Countries can also report visibility, which is different from RVR, in statute miles or nautical miles. Again rough equivalences are in place:

1/4 SM = 400 m
1 SM = 1,600 m.
1 NM = 11/4 SM.
1 NM = 2,000 m.

Substituting visibility to RVR
With all these approximate conversion factors defined, we can build a table for visibility by increments of 1/4 SM or 400 m (on the right hand of the table below), and use meter values, the common unit, to establish approximated RVR-visibility pairs.

(Source: Jeppesen)
Visibility, contrary to RVR, is not an exact measure. It's based on eye performance and available distinctive features of the surrounding environment. Moreover, visibility isn't generally evaluated for the same volume of atmosphere than RVR.
Sources:

FAA Order 6560.10C, Runway Visual Range.

Jeppesen Explanation of Common Airport Operating Minimum Specifications


How many people can stand on airliner's wings?

Disregarding the fact that the wing load vector on a passenger jet usually points up, not down, the wings will usually bear most of the load for the entire aircraft. The MTOW for an MD-80 is 63,500 kg. If an "average" passenger is 80 kg, then that is 800 passengers. Obviously that is going to be greater than the number of passengers on the flight, because those wings had already lifted those passengers (and the rest of the plane) into the air in the first place.


What is an air traffic controller's role in handoffs?

In most modern ATC units, almost all transfers are conducted as “silent transfers”. A silent transfer is a transfer where all necessary information about a flight is sent in advance to the next ATC sector by an automated system. In this case, the controller does not have to manually talk to the next sector, but will simply instruct the pilot to switch to the next frequency prior to the area of responsibility border.
Where manual coordination is required, it is most likely done by the planning controller (PLC). As opposed to the executive controller (EC), who talks to the planes, the PLC (who will be seated right next to the EC) handles coordination with adjacent sectors via dedicated telephone lines.

There are two main parts of a transfer: the transfer of communication and the transfer of control. The transfer of communication is the actual frequency switch – the instruction for the pilot to switch from one frequency to another. The transfer of control is the transfer of responsibility of the flight from one controller to the next.
Before answering your question directly, let us establish the premises of the question.
Note: this answer refers primarily to European procedures, and is largely based on this EUROCONTROL document
In respect to your question, the transfer of control is the interesting part.
Firstly, we must realise that there are two fundamentally different premises for a transfer of control. Either the transfer takes place from one position/sector to another position/sector within the same ATC unit (for example between two area control sectors in the same area control centre), or the transfer takes place from one ATC unit to another (for example when a flight crosses a state border).
In the first case, the adjacent sector will typically already have access to information about the flight, since both sectors rely directly on the same data source. In the second case, this might not be the case.
Additionally, in the first case, controllers will often be physically seated right next to each other. For units where paper flight progress strips are still used (mainly some approach and tower units), this enables controllers to physically pass the flight progress strip to the next controller.
In both cases, there are four required stages which lead up to a transfer of control (refer to ICAO document 4444, section 10.1):

a) Notification of the flight in order to prepare for coordination, as necessary;
b) Coordination of conditions of transfer of control by the transferring ATC unit;
c) Coordination, if necessary, and acceptance of conditions of transfer of control by the accepting ATC unit; and
d) The transfer of control to the accepting ATC unit or control sector.

Doc 4444 also states that:

ATC units shall forward from unit to unit, as the flight progresses, necessary flight plan and control information.

Now, your question is, to what extend is this data transfer process automated. ICAO document 7030 gives us a clue to the background of the answer:

When so agreed between adjacent ATC units, a computer-assisted coordination process shall be introduced to eliminate the need for verbal coordination of boundary estimates and to reduce the amount of manual data input into ATC computers.

In most modern ATC units, almost all transfers are conducted as “silent transfers”. A silent transfer is a transfer where all necessary information about a flight is sent in advance to the next ATC sector by an automated system. In this case, the controller does not have to manually talk to the next sector, but will simply instruct the pilot to switch to the next frequency prior to the area of responsibility border.

Silent transfer of control procedures require that traffic is predictable and sufficient system support is provided to ATCOs to ensure:
-They are in possession of all elements related to the aircraft profile and
-Should the agreed conditions of the transfer change, they have the means to speak to each other such that new conditions are agreed expeditiously and safely.

Silent transfers are based on the exchange of flight data, which happens through connected Flight Dara Processing Systems, which make use of the OLDI protocol.

The operational use of connections between Flight Data Processing Systems (FDPSs) at ACCs for the purpose of replacing verbal "estimates" is referred to as On-Line Data Interchange (OLDI). The implementation of basic OLDI messages is mandatory in accordance with Regulation (EC) No 1032/2006. These messages are defined by the EUROCONTROL Specifications

What this regulation means in practise is that, within Europe, silent transfers are used more often than not. However, you will also see units where a manual coordination prior to a transfer is required, for example flights crossing the border from certain European countries to certain non-European countries. Where manual coordination is required, it is most likely done by the planning controller (PLC). As opposed to the executive controller (EC), who talks to the planes, the PLC (who will be seated right next to the EC) handles coordination with adjacent sectors via dedicated telephone lines.


What is the weight of the bulletproof cockpit doors of a Boeing 747?

From federalregister.gov:

  The FAA also assumed that the average safety door system adds 100 pounds to a large airplane. This additional weight would have minimal impacts on weight and distance limitations.

For a large airplane, like say the 747, it seems the weight addition is around 100 lb (including the other safety features such as the surveillance). As for the exact weight before/after, this information is not readily available as the doors are not sold to the public. But feel free to get in touch with Boeing if it's for research/educational purposes and such.

If the information provided by the seller on this eBay item is correct, then the weight of a 747-400 door is 59 lb. And also from eBay, is a bullet proof 737 door shown below.


Which part of the boundary layer(chordwise) contributes most to friction drag? fore? aft? Why?

It depends on the airfoil and the free stream conditions, but some general trends can be observed.

First, skin friction drag is dominated by viscous effects, so the laminar or turbulent quality of the layer is important. Laminar layers are less draggy that turbulent ones, mostly by merit of being thinner. This means that the leading edge will often suffer less viscous drag until the boundary layer transitions from laminar to turbulent, which may happen next to the stagnation point or further downstream. The layer will then continue to grow, so, for attached flow without re-circulation bubbles, the friction maximum can be expected to be near the trailing edge (not necessarily on it).

Second, for this viscous friction to be drag in the usual sense, it has to provide a force opposed to the direction of flight, so one would integrate its product with such a vector along the surface of the airfoil. This would mean, again, that the leading edge contributes less than its fair share, as friction forces directed up or down relative to the free airstream are not drag.

So the general answer would be that the aft part of an airfoil provides a larger friction drag contribution than the fore.


Are there any remaining flying boat or seaplane airliners in operation?

As far as I know, there is no actual flying boat in use at an airline. The flying boats that are still in commercial operation are typically used for fighting forest fires or maritime patrol. This may change in the near future since there are currently at least two flying boats in development that might be used by airlines:

Dornier Seastar CD2: This is a newer model of the previous Seastar, which had its first flight earlier this year:

Dornier Seawings flew its new-generation Seastar amphibian for the first time on 28 March from its base in Oberpfaffenhofen, Germany.
[...]
Dornier says the aircraft will be offered in various configurations including cargo, passenger, special missions and VIP transport.

(flightglobal.com, emphasis mine)

AVIC AG600: This is new aircraft developed in China and one of the biggest flying boats ever. It had its first flight in 2017 and according to Wikipedia is expected to be delivered by 2022, possibly also in a passenger variant:

Further variants may be developed for maritime surveillance, resource detection, passenger and cargo transport.

If you are not just interested in pure flying boats, but also floatplanes, then there are many airlines world wide that operate these on regularly scheduled flights. One of the biggest is Trans Maldivian Airways operating various variants of the DHC-6 Twin Otter. They operate 55 seaplanes, which according to Wikipedia makes them the biggest seaplane airline:

TMA currently operates the world's largest seaplane fleet.

They offer flights to over 80 destinations:

Trans Maldivian Airways currently offers transfer services to more than 80 Maldives resorts, flying over 1 million passengers per year to their holiday hideaways.

(transmaldivian.com)
This is their main terminal at Velena International Airport:

(image source: Wikimedia)


Can simultaneous departures be authorized from converging airports?

If this were in an FAA ARTCC's airspace, they'd handle them as one airport, because of their proximity.
The protected lateral airspace for an aircraft is 4 miles either side of the course to be flown. That eliminates a lot of possibilities.
In a non-radar environment, with only 3.8 miles between the airfields, you need a reduced separation rule, such as the 13/3 DME rule (7110.65 6-2-1, a3). One and two minute rules won't work, because of the convergence.
If you have a NAVAID that the departures fly over, you can use 3 miles between aircraft (faster in front), until their courses diverge.
The divergenge has to be 45 degrees or more, and the NAVAID has to be within 13 DME of both airports to  use the rule.
The 44 knot rule (7110.65 6-4-2) could possibly be used if you can maintain a minimum of five miles between the aircraft. Remember to account for any local speed restrictions (such as 250 knots below 10,000 feet) that may keep you from having 44 knots between your aircraft. Also, the 44 knot rule is based on filed true airspeed, not ground speed. But again, someone has to wait.
If this is a radar environment (I'm assuming you use 3 miles separation), you can release the second aircraft as soon as you get radar on the first (using radar contact within one mile of runway end) as long as you maintain 3 miles.
These rules are usable in either terminal or enroute environments. There may be more in 7110.65 chapter 3, but I don't go there, being a center controller.
If it's possible to post a plan view of the airspace, there's some CTO rated controllers on here that could give more definitive answers.


Can an airliner complete a flight with one pack inoperative?

The 747-8 has three packs, and it is feasible to complete the flight with one of them inoperative (in case of aircraft with two packs, cabin altitude can be maintained win any one). The following is taken from the Minimum Equipment list of 747-8:

Screengrab from 747-8 MEL

As can be seen, flight is possible with some limitations. In case of a failure in-flight, the flight crew would follow the applicable checklist and decision will be taken whether to continue the flight or not (as altitude is limited). In case of failure, the appropriate warning message will be displayed (the pack, sensor, valve etc.)


What phenomenon causes the increase of drag with rain?

While Peter Kämpf already commented the effects I'll take a look at the numbers. Don't expect this calculations to be exact predictions, rather worst cases to know the magnitude of following effects:

Mass increase due to rain drops
Forces due to drops hitting the wing
Early tripping of the boundary layer

After deducing some equations I'll feed them with the data of two different airplanes.

Mass increase due to rain drops

The dew layer you find on your airplane in the morning can reach a maximum altitude of 0.8 mm. Raindrops, which do not fill the complete wing surface, don't usually exceed 2 mm diameter.Therefore taking an average distributed height of $h_W=1mm$ for the water on the wing should be still a worst-case prediction.

$$m_{Drops}=\rho_{W} \cdot A\cdot h_W$$

$A$ is the projected area of the aircraft on the horizontal plane and $\rho_W$ water density.

Forces due to drops hitting the wing

Normal rainfall intensities are about 5 mm/hour and we already speak about violent rain with precipitation rates beyond 50 mm/hour. But let us take the heaviest rate ever measured: $I_R=38mm/min$.

Drops fall normally with $v_{Drop}=10m/s$.

To simplify the calculation I'll assume vertical rain and that once a drop hits the airplane it sticks to it. In reality you don't accelerate every drop to the airplane speed nor slow its vertical speed down to 0.

i) Drag increase

$$ \Delta D= \rho_{W} \cdot I_R \cdot A \cdot v_{airplane}$$

ii) Lift decrease

$$ \Delta L= \rho_{W} \cdot I_R \cdot A \cdot v_{Drop}$$

To calculate the total drag ($D=C_D\cdot \frac{\rho_{Air}}{2} V^2 \cdot A$) I've used $C_D=0.035$. $V$ is the cruise speed of the aircraft.

Early tripping of the boundary layer

While it's possible to find airfoil polars in rain searching the Internet, I'll first look at a "bugs influence" diagram where you can see the effect of small disturbances at the nose without other effects overlayed. Bugs and raindrops are similar in size, therefore the comparison should be valid.

Source

The polar above shows how the drag can double (100% increase)just because of some small disturbances at the leading edge. Keep in mind that in modern profiles the effect will probably be smaller. The next polar is from a transport aircraft airfoil.

Source

While not so important as in the glider airfoil, the drag coefficient increase (experimental results) is everywhere at least a two-digit percentage.

Airplanes

I've taken two airplanes with really different wing loadings: A1 would be something between the two Solar Impulse models and A2 a single engine four-seater like a Cessna 172. The last three rows give the drag, lift and mass difference as described above as a percentage of its total value.

|                       |            A1 |     A2 |
|-----------------------+---------------+--------|
| Mass m [kg]           |          1600 |   1000 |
| Area A [m^2]          |           210 |     20 |
| Wing loading [kg/m^2] |           7.6 |     50 |
| Cruise speed V [m/s]  |            20 |     58 |
| Lift L [N]            |         15696 |   9810 |
| Drag D [N]            |          1800 |   1323 |
| Drops mass mW [kg]    |           210 |     20 |
| Drag increase dD [N]  |          2660 |    703 |
| Lift decrease dL [N]  |          1330 |    127 |
|-----------------------+---------------+--------|
| dD/D [%]              |           147 |     53 |
| dL/L [%]              |           8.5 |    1.3 |
| mW/m [%]              |            13 |      2 |
|-----------------------+---------------+--------|

SUMMARY

For a normal GA airplane the water mass on the wings and the lift decrease influence due to raindrops hitting the wing even considering the worst possible conditions are low single digit percentages.

While drag increase due to drops hitting the wing is relevant in the extreme case I took here, under normal conditions it should be below single digit percentages too.

On the other hand the drag increase due to the early tripping of the boundary layer is at least a two digit percentage, at high lift coefficients even more.

Airplanes with lower wing loading are more affected with rain precipitation.


When the brakes are checked, what do the firemen actually do?

There are specific protocols that procedurally are required to be followed. Insofar as brake inspection is concerned, it would have been obvious from the trucks that there was no brake fire. It's also obvious that there's not a major amount of smoke coming from the brakes. As they approached the landing gear, they would have smelled serious brake heating. Glowing brakes would be seen then if not sooner. A close visual inspection for very light smoke and sensing the heat coming off the brakes would give them an idea of the rate of brake vaporization. It's a subjective judgement based on what they see and feel.

As I understand it, tires that dangerously overheat will explode before melting, and that's why thermal plugs are used which melt and deflate the tire to prevent their exploding.

At a landing in Nandi, Fiji (short runway) with what turned out to be a tailwind in a 747-200 at near-max landing weight, we had to use max braking, and I called for huffers to cool things down, and of course for an inspection. I exited the aircraft as quickly as possible to see how bad things were. I was amazed and alarmed to see thick dark grey smoke pouring from the body and wing landing gear wheels. I thought we were close to having a fire. However, the ground personnel assured me that there was no cause for alarm, that the smoke was just brake vaporization that would shortly stop as they blew air on them. It did, and after refueling we departed without incident.


What are the requirements for a small jet type rating in the UK?

As far as I know, you can't get a type rating for a homebuilt jet in the UK. You can do so in the US but you have to find an instructor and examiner rated by the FAA to do that. I would suggest you talk to the manufacturer of the kit about this. They are the most likely to know the answer, but I would not hold out much hope. The UK CAA has historically demonstrated they are not too keen to let people fly homebuilt jets.


Can anyone help me identify the plane in this photograph?

What you have there is I believe a Boeing Model 80A-1:

Source

Source

You can read more about it on Wikipedia: Boeing Model 80

The Model 80 air transport aircraft was built in the mid 1920's. It is notable as being the aircraft used for the first flight to feature a flight attendant, which were registered nurses at the time.


How are the navaids that are on the airport ground powered?

They use the airport power. The airport and its important equipment have backup power and/or a dedicated power plant (which itself will have backup plans).

This is what the FAA says:

  The FAA recognizes the need to have a reliable power source to operate NAVAIDs, even during utility power outages. Order 6030.20 establishes Continuous Power Airports (CPAs) that provide continuous operations in the event of an area-wide utility failure. Backup power to designated runways at these airports must be able to supply power for at least 4 hours for runway lighting as well as navigation, landing and communication equipment. In addition, FAA policy also requires that power systems used for support of Category (CAT) II and CAT-III operations must be capable of transferring to an alternate source within one second.

  Source: AC 150/5300-13A

Basically it's to avoid having to shutdown a major airport. Select airports and runways have to be able to operate.

ICAO recommends the same thing and lists the criteria airports need to meet in Annex 14, section 8.1 Secondary power supply.

For example:

  8.1.5 Recommendation.— Requirements for a secondary power supply should be met by either of the following:

    — independent public power, which is a source of power supplying the aerodrome service from a substation other than the normal substation through a transmission line following a route different from the normal power supply route and such that the possibility of a simultaneous failure of the normal and independent public power supplies is extremely remote; or

    — standby power unit(s), which are engine generators, batteries, etc., from which electric power can be obtained.

For navaids in general that are not within an airport, then ICAO Annex 10, Volume I, Part I, Chapter 2 handles the recommendations.


Do all aircraft carry depleted uranium as counterweights?

From my research, it looks like about 0.1% of all aircraft carry depleted uranium counterweights.

The Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials (NUREG-1717), on page 3–260, gives a table showing that 430 domestic United States aircraft were delivered with depleted uranium counterweights, and says that "A reasonable estimate is that 50% of these aircraft still contain DU counterweights." So there are about 200 aircraft in the United States which contain depleted uranium counterweights.

Meanwhile, the FAA's "Air Traffic by the Numbers" publication says that there are over 200,000 aircraft in the United States currently.

So no, very few aircraft use depleted uranium counterweights.


Was there ever a fuel-injected Spitfire?

Yes there was. A Spitfire which was converted by Daimler Benz engineers to use a DB 605 engine. See the following links:

https://www.klassiker-der-luftfahrt.de/geschichte/flugzeuge/daimler-benz-versuch-die-daimler-spitfire-die-db-spitfire-zeigt-gute-flugeigenschaften/615458?seite=2

https://defenceoftherealm.wordpress.com/2014/11/17/the-franken-spitfire/


Why is the DC10/MD11/TriStar vertical stabilizer noticeably smaller than other contemporary aircraft?

Two characteristics drive vertical tail size in airliners:

Critical engine out: Here the tail needs to compensate the yawing moment of the live engine on one wing.
Yaw damping: This is aided by a yaw damper, but enough damping must remain for the case of a failed damper. Especially the dutch roll eigenmode is driving tail size.

On the other hand the tail should not be bigger than absolutely necessary to keep drag and weight down. On the Tristar, the big intake added so much tail area that a relatively small tail was sufficient. Note that the engine intake on the Tristar is much longer than on the DC-10 because of the S-duct. The flow must be brought down to the engine without internal flow separation, which is made easier when the intake is longer.

Since in the engine-out case only one third of total thrust creates the yawing moment which the tail needs to overcome compared to one half of the thrust in case of the A310, the vertical tails of both the Tristar and DC-10 are smaller relative to that of the A310. The A310 is a shortened version of the A300, so the reduction in fuselage length made an especially large vertical tail necessary. If you look at the vertical tails of the MD-80, the Il-62 or the VC10, they are even smaller since very little yawing moment needs to be compensated in the engine-out case. Adding to this, the T-tail configuration makes the existing tail more effective due to the endplate effect (PDF!) of the horizontal tail on those three types.

Vickers VC10 (left) and Tristar (right) tankers in flight (picture source).


How does the turbulent boundary layer thickness affect separation?

On a flat plate the thickness of the boundary layer grows along the flow path without a tendency to separate. Therefore, thickness alone is not the culprit.
However, when the pressure gradient in flow direction becomes positive (increasing pressure), the flow will slow down and thickness grows much faster than in non-decelerating flow. Now separation happens when the speed at the surface drops to zero. Right before separation you will see an exponential growth of the boundary layer, but it is only an indication for the decelerating flow which really is to blame for the separation.


How many flying mileage a pilot should have per year in order to keep his licence valid?

There’s no minimum flight time required to retain a pilot certificate, though there are minimum currency standards in order to act as PIC in certain flight situations, or to carry passengers.  See §61.57.

Pilots are also required to complete a Bienneal Flight Review ever 24 calendar months in order to act as PIC aboard an aircraft.  Any successful practical exam for an airman certificate additional category, class or type rating can be substituted for a BFR.

Typ ratings listed on airman certificates expire after 12 calendar months unless the applicant undergoes a recurrent training for the aircraft type and pass a practical exam administered be an aviation examiner or check airman.

Flight instructor certificates do expire after 24 calendar months, unless the CFI:

Passes a flight instructor refresher course containing both ground and flight training within the preceding 3 calendar months on the expiration date.
Pass a practice exam for one of the ratings listed on their instructor certificate
Recommends at least 5 students to take a practical examination in which 80% of whom pass, or
Work as a chief pilot or check airman for a Part 121 or 135 operation.

See §61.197


What is the aircraft loss-rate from Nimitz-class aircraft carriers?

The Naval Safety Center publishes some useful stats here.

(Rates are per 100,000 flight hours per year. Source.)

(Source.)

A few more details are available in the summaries. One example:

Other examples:

E-2C: Electrical arcing at vapor cycle power receptacle led to aircraft fire in the hangar bay.
A single F/A-18C crashed 6.6 miles northwest of Lakenheath, England. Event Cost \$72,000,000
MV-22: While recovering to LPD, MV-22 landed short of spot 2, main landing gear in deck edge netting
Engine fire leading to ejection. Event Cost \$71,000,000
Two CH-53 helicopters crashed while on training flight. All 12 crewmembers deceased.
AV-8B experience catastrophic engine failure during takeoff. Event Cost \$62,800,000
AV-8B experienced loss of thrust, pilot ejected safely. Event Cost \$62,800,000
2xF/A-18F Collided during Air-to-Air training. 2 aircraft lost. No fatalities. Event Cost \$173,580,662
EA-18G inflight engagement during night CV landing caused extensive damage to aircraft
F/A-18 impacted ground during air show practice. Event Cost: \$75,400,000
MH-60S crashed into James River while performing SAR training flight. Event cost: \$25,508,816
KC130T EXPERIENCED HAIL DAMAGE WHILE PARKED ON THE RAMP AT PETERSON FLD, CO
(KCOS)
F/A-18C crash during night air-to-ground training mission. Event cost: \$76,500,000
[snip]
T-45C: ACUTE PHYSIOLOGICAL EPISODE RESULTS IN ACTIVATION OF THE EJECTION SEQUENCE BY CREw. Event Cost \$37,800,000
A single T-45C impacted the ground at high energy. \$37,800,000
[snip]
Aircraft impacted a tree during low level training. Aircraft recovered safely.
[snip]
MV-22 ditched off Okinawa during NVD training mission. Event Cost \$80,600,000

Class A mishap definition:

  \$2,000,000 or more and/or aircraft destroyed [or] Fatality or permanent total disability

Just note that these are just Class A's. It doesn't include B's, C's, or D's. Some of these aren't carrier related.

On a completely unrelated note, notice the costs. Modern a/c are expensive (although not all that is flyaway cost).


What is the unit for the oil quantity display in the Airbus A320 ECAM?

The answer is actually in the image: Below "OIL", it says "QT", which according to the "Abbreviations" table under "General Information" in the A320 FCOM, means

  Quart (US)


How does a jet fighter with water-skis land safely?

In the specific case of the F2Y, this video report from the US Navy and General Dynamics shows how it was done.

In the video: It lands on water the same way as any other amphibious aircraft. The only difference is that the engine intakes must be protected from water because too much of it will cause the engine to flame out and shut down.


Are children safe when seated in lap during a flight?

Your instincts are correct, or at least the NTSB agrees with you - they don't like the idea of "Lap Children" on aircraft, and they've come out and said as much in this Safety Alert.

They reiterated that position again in a 2010 letter to the FAA which includes a number of incidents from NTSB investiations, including:

  … on July 19, 1989, United Airlines flight 232 crashed during an attempted emergency landing at Sioux City, Iowa, after the fragmentation and separation of an engine fan disk. Of the 296 airplane occupants, 111 were killed, 47 received serious injuries, 125 received minor injuries, and 13 were not injured. Four children, ages 11 to 26 months,17 were aboard the airplane and were being held by adults. A 23-month-old child was killed, and the other three children received minor injuries. The parents of the four lap-held children were instructed to place their children on the cabin floor and hold them in that position while the adults assumed the protective brace position. After the accident, three of the parents reported that they were unable to hold onto their children during the accident sequence.

and

  … USAir flight 1016 in Charlotte, North Carolina. The flight crew decided to continue an approach into severe convective activity and was executing a missed approach when the airplane collided with trees and a private residence near the airport. Of the 57 airplane occupants, 37 were killed, 16 received serious injuries, and 4 received minor injuries. Among those occupants who were killed was a 9-month-old child who was held by her mother on her lap. The child’s mother survived the accident but was unable to hold onto her child during the impact sequence, and the child struck several seats. The NTSB believed that the child might not have sustained fatal injuries if she had been properly restrained in a child restraint system.

Granted both of these were pretty severe accidents, but the NTSB investigators found that the lack of restraints was potentially a major contributing factor to the injuries of children on these flights.

In that same letter the NTSB also notes that unrestrained children are not just a hazard to themselves in a crash:

  Passengers are required to securely stow all carry-on baggage during takeoff and landing because of the potential risk of injury to other passengers in the event of an unexpected hazardous encounter. However, passengers are permitted to hold a child of equal size and weight in their lap. When children under 2 years of age are not required to be restrained for their own safety, the safety of their fellow passengers also becomes an issue.

See here for more NTSB pronouncements on the subject of child safety in transportation.
They even have some excellent videos and simulations showing restrained versus unrestrained children.


Is a rotary wing craft capable of supersonic flight?

Currently there is no rotary wing craft capable of supersonic flight.

Combined with the forward motion through the air, the rotating blades attack the air on one side and retreat backwards on the other.  As the aircraft moves faster this poses 2 problems:

The retreating blade has a point of zero air speed, starting from the axis at hover and moving to the tip with forward speed, an effect known as P-factor.  Eventually a large portion of the blade has negative airflow (backwards to what it had when hovering) causing loss of lift control on that side (there may still be lift, but the pitch of the blade has little influence). The craft will roll (and I believe gyro forces will bring the pitch up, and the craft will recover)
The advancing blade will go supersonic, starting from the tip. Aerodynamics change.

There are ideas of new blade actuators that can change the blade for 1) reverse airspeed and 2) supersonic aerodynamics.  As you have noticed, nothing has panned out so far...


Why does a turn and slip indicator matter?

The turn and slip instruments are combined for convenience and by convention more than anything else, slip is important whether you are in a turn or not. When you slip it means one wing is more directly pointed into the airflow, which increases lift for that wing in comparison to the other. At a high angle of attack, for instance a climb and close to stall speed, a slip can put one wing into a stall, causing the non-stalled wing to flip the airplane. When done deliberately it's an aerobatic maneuver called a snap roll, when it's not deliberate it's a major cause of stall-spin accidents on take-off and approach. So slip is dangerous in some situations.

In level flight slip creates drag, so it's worth keeping the ball in the middle when safety is not a concern as well.

As for deliberate slip as I said before slip can be induced for aerobatic maneuvers like snap rolls and spins, slip can also be used for non-aerobatic maneuvers like side-slips, where you put the airplane out of balance to increase drag, allowing more rapid descents without increasing airspeed.


Is is possible to have an aircraft launched from a submarine or directly from under the water?

The Japanese navy did that in WW2. https://en.wikipedia.org/wiki/I-400-class_submarine


Is the F-117 fleet at Tonopah Test Range being mothballed?

Some F-117s under storage (not in active service) were still flying sometime back because their storage type required for it. Attributed to USAF by http://intercepts.defensenews.com/2014/11/we-now-know-why-the-f-117-is-still-flying/:

  Per Congressional direction within the FY07 National Defense Authorization Act the aircraft were placed in Type 1000, flyable storage for potential recall to future service.  In order to confirm the effectiveness of the flyable storage program, some F-117 aircraft are occasionally flown.

The same article gives some details about the type 1000 storage:

  Aircraft in Type 1000 storage are to be maintained until recalled to active service, should the need arise. Type 1000 aircraft are termed inviolate; meaning they have a high potential to return to flying status and no parts may be removed from them. These aircraft are ‘re-preserved’ every four years.

However, this may soon change as the House Armed Services Committee’s version of the National Defense Authorization Act repeals the 2007 provision for storage:

  This section would amend section 136 of the John Warner National Defense
  Authorization Act for Fiscal Year 2007 (Public Law 109-364) by striking subsection (b), which would remove the requirement that certain F-117 aircraft be maintained in a condition that would allow recall of those aircraft to future service.

So, while F-117s are not in USAF service, some were still flying (until recently) though they are probably going away for good soon.


I would argue that it is most important on takeoff. The reason is that most planes require more distance for takeoff than for landing (partially due to higher weight). Also, it is generally easier to abort a takeoff than a landing (when on the ground at least).

Both landing and takeoff distance calculations are performed (which should take slope into account) to ensure that there is sufficient distance for the aircraft. However, in addition to aborting a takeoff being easier, more can go wrong in a landing. Windshear or improper approach settings can cause an airplane to touch down later or faster, which risks an overrun. During takeoff, the plane has until V1 (takeoff decision speed) to abort if any issues arise.

However, this certainly depends on conditions. Aircraft condition, wind and runway surface condition can increase the distance needed for landing (or aborting a takeoff). If reverse thrust is not available, there is a tailwind, and the runway is wet, that could change the situation.


Image source

Larger helicopters have landing wheels, and as we can see on the picture above, they are placed as far outward as practically possible in order to provide stability in the landing. Touch down one wheel on an sideways inclined slope, lower the collective, and the helicopter will align itself onto the slope with:

The location of the Centre of Gravity (CoG) always in between the wheels. The higher the CoG, the wider the landing gear impact points must be.
The weight being supported on clearly defined and structurally reinforced points. Even if the bottom of the helicopter is perfectly flat, the landing ground may not be, and to support all of the weight at any random point at the bottom requires a lot of relatively useless weight for the re-inforcement.
The behaviour after first wheel touchdown being clearly defined. The wheel is a point of impact upon the landing plane, mathematically much more defined than a plane of impact upon a landing plane if the latter is curved.

All the above is for wheels, which allow the helicopter to taxi on-ground. Skids perform all of the above functions apart from the on-ground taxiing, and are cheaper and lighter than retractable landing wheels. Of course, the other downside is that they have more drag.

One would not want to land this helicopter without the skids!


What is the naming convention for European airways?

ATS routes in Europe are designated just like the rest of the world. ICAO publishes guidelines for the designation of ATS routes in Annex 11, which are adopted by almost all countries.

A route will consist of a possible prefix (see below) a letter (see below) and a basic designator (a number between 1-999).

The three types of prefix are:

K (Kopter) to indicate a low-level helicopter route

U to indicate an upper route, available only in upper airspace

or S to indicate a route only used by supersonic aircraft (not very common).

The letters can be:

A, B, G, R for regional routes which are not RNAV routes

L, M, N, P for regional RNAV routes

H, J, V, W for non-regional non-RNAV routes

Q, T, Y, Z for non-regional RNAV routes

In addition, states may add the letters F or G to the end of a route to indicate that the route is in class F or G airspace respectively. To my knowledge, this is not very common (and most ATS routes are in controlled airspace anyway).

Examples:

KY80 ("Kopter Yankee 8-0)

UN872 ("Upper November 8-7-2)

T54 ("Tango 54")


What does the "visibility" number mean on an approach plate?

If this question is about the US, the FAA's Chart User's Guide is a useful source for questions about approach plates or any other charts. It says:

  This section gives the pilot the lowest altitude and visibility
  requirements for the approach. There are two types of landing
  minimums: Straight-in landing or Circling. Straight-in landing
  minimums are the MDA and visibility, or DH and visibility, required
  for a straight-in landing on a specified runway. Circling minimums are
  the MDA and visibility required for the circle-to-land maneuver.

And:

  The visibility values are shown after the DA/DH or MDA. They are
  provided in statue [sic] miles or runway visual range (RVR). RVR is reported
  in hundreds of feet. If the visibility is in statute miles, there is
  an altitude number, hyphen, whole or fractional number, e.g. 530-1.
  This indicates 530 feet MSL and 1 statute mile of visibility. The RVR
  value is separated from the minimum altitude with a slash, e.g.,
  1540/24. This indicates 1540 feet MSL and RVR of 2400 feet.

The number is indeed a limitation: if the required visibility doesn't exist then the pilot can't use the approach. However, there are some differences in what that really means depending on the type of flight: an airline flight (part 121) can't even start an approach if the reported visibility is less than the approach requirements; a private flight (part 91) can start an approach but may not land if the flight visibility is below minimums. This question might be relevant.


Can I preheat my C150 by placing a space heater in the cabin?

Almost no heat gets to the engine.  What hot air drifts through the heater SCAT hose  might warm the exhaust muff a bit.  Plus you have that fire hazard heater in the cabin.

Get some of that aluminum flexible ducting used for clothes dryers and form the end to fit over the heater, and tape it on with aluminum speed tape. Set the heater on the ground to the side with the duct stuck in the bottom of the cowl.  Put some foam in the cowl inlets. 30 minutes to an hour is all you need.

A lot of people just stick the heater itself under the cowl but it's way safer to duct the air in with the heater outside and works just as well.

Preheating is traditionally all about warming up thick oil and the galleries the oil has to flow through, not so much heating the metal itself for the sake of the metal (the cylinder doesn't much care if it warms to 350F starting out at 20F or 50F as long as oil is getting to the parts).

If the OAT is above 20F and you are using multi-grade oil like Aeroshell 5W50, the oil will flow fine at ambient temperature and there is really no need to preheat if the rise in oil pressure is not significantly delayed from warm weather starting. Not saying not to do it, but if I had no preheater and it was 20 degrees, and I was using multigrade oil, I wouldn't ground myself and would start the engine anyway.


Can a Boeing 747 or A380 climb with only one engine?

I doubt that either aircraft can climb on a single engine (though momentum and airspeed could help, as @RonBeyer already commented). The closest an aircraft came to this condition was the British Airways Flight 9 when it ingested volcanic Ash.

During this incident, the aircraft flew on one engine for around 90 seconds. In this case, a report from the flying magazine says:

  On one engine they could maintain height at 13,000 ft; over the next five minutes, the next three engines relit, and they begun a climb.

This seems to indicate that the aircraft was not able to climb with one engine. However, during this incident, the aircraft was not climbing, but was descending at 1800m per minute.

Note: There seems to be some confusion about the altitude. The captain's website gives the altitude as 12,000 ft.


How do I estimate piston aircraft fuel efficiency?

Yes there is a simple rule of thumb for what is known as Specific Fuel Consumption that you can apply to estimate the fuel burn of most piston engines:

An air cooled carbureted engine, leaned, will burn roughly 0.44 to 0.45 lb/hp/hr.
With Fuel Injection, a bit less, maybe 0.41 or 0.42-ish.

Cars with electronic sequential fuel injection are in the high 0.3s.  Diesels are in the low 0.3s

2 strokes are up in the mid 0.5s.

Turbo props are very thirsty and are in the .6 range.

Take a Cessna 150.

75% cruise is 75 hp.
X 0.45 = 33-34 lb/hr.
= 5.6 usg/hr.

Which is about what you will find in the POH, or close enough anyway.

Want to know the fuel burn of an R-985 powered airplane?

450 X .75 = 337 hp
@ .44 lb/hp/hr = 148 lb/hr
= 26 usg/hr, which sounds about right for something like a DeHavilland Beaver.


Has a scheduled passenger flight ever stalled because of shifting cargo?

Yes, a LET-410 crashed in the DR Congo, apparently because a crocodile escaped. Passengers trying to escape the animal apparently caused enough of a load shift to result in a crash.

Not a shift, but Air Midwest Flight 5481 crashed due to a combination of a  weight and balance error coupled with a misrigged elevator.

In general, it's harder to have a significant load shift on a passenger aircraft since it's easy to check the distribution of passenger loads, people are well restrained by seat backs, and unless something else is catastrophically wrong (fire), passengers don't all get up and move to one side of the aircraft.


What is the authority of the Air Boss at an airshow?

Air bosses who orchestrate air shows do not receive special training or certification . Infact FAA also lacks the resources to inspect all aircraft that participate in air shows

FAA doesn't have certification standards for air bosses . Waivers for customary flight standards are provided to air shows, which then hire people to direct planes in flight.

There is no training in place right now for an air boss

http://www.rgj.com/story/news/2014/03/23/ntsb-hearing-addresses-distance-between-race-course-and-spectators-other-issues/6587627/

However,  typically former air-traffic controllers with a great deal of aviation experience are hired as Air Bosses at Air Shows .

The air boss implements the standards on the FAA waiver

Firms like ICAS provide Air Boss training


Could the Airbus A350 be converted into the role of air tanker / be used for aerial refuelling?

Yes, it could be done. There is an A330 already working as fuel tanker.

Image Source: Wikipedia

Airbus might build a A350 air re-fueler as mentioned here:

  Airbus is already offering a tanker version of the A330, and could
  (potentially) upgrade their proposal with an A350 air-refueler. The
  A350 would offer a substantial increase in fuel offload from existing
  tankers, as well as the 767.


PT-6 Starting problems - PT6A - 67B, installed on a PC12

Either the starter generator isn't making the torque it should be making, or there is a fuel flow issue.  If I was betting 10 bucks on the result, I'd go with weak starter/generator and swap it out if another was available, or do diagnostic testing on the unit like insulation resistance checks and other electrical tests on the motor.

Regardless, if your mechanic is not sure how to proceed he/she should be on the phone to Pratt & Whitney Canada tech support or going through the PWC online portal to access the Fault Isolation Manual for that engine and just follow the steps.

If you're a pilot standing by watching the action, you'll really piss off the mechanic by relaying him troubleshooting instructions from some anonymous nobody from ASE, so I would only intervene if the mech was hiding in the bathroom and refusing to come out.


Does rolling or yawing affect the angle of attack?

No that's not how it works.  You shouldn't need "yawing" movements on final before the landing flare.  That implies that you are using rudder to push the nose left or right to keep the runway sight picture where you want it, a very bad practice.

Never use rudder to stay aligned with the runway, except in the landing flare.  Other than that, only use rudder to keep the ball centered, or to side slip to lose altitude.  At all times, unless you are side slipping on purpose, use coordinated banked turns to stay aligned with the runway prior to the flare.

The rolling movements should be just those movements required to make coordinated banked turns to adjust heading to stay on centerline, or to get back on centerline.  Maybe 20 degrees of bank. Ball centered as much as you can keep it centered in bumps.

Moderate banked turns in a descent with ball centered create zero risk of stalling if speed is attended to.  Stall/spin accidents happen when pilots try to shove the nose with rudder to point it at the runway, causing uncoordinated flight, on top of sloppy speed control, so that if they get too slow, with the airplane slipping or skidding, when it stalls it flicks over the inside wing and down you go on your ride to oblivion.

If you are keeping bank angles within reason, ball centered, and speed on the proper approach speed, you won't stall the plane and normal control inputs will not get you close to stalling the plane. And with any modern plane, if you do stall it but the ball is centered, you won't depart in a spin and you can recover instantly.  Coordinated ball centered flight is the most critical item after speed control.


With a Pandememic grounding many to their residence.... How to maintain flight hours?

Many countries are extending validation periods, but ultimately it's a question that isn't fully answered yet. Right now the focus is on the pandemic - the practical concequences come second.

Chances are it will be a combination of extending legally mandated periods, and common sense by operators.


What are the protrusions on the sides of the fuselage of the F-16I?

They are Conformal Fuel Tanks.

See http://israeli-weapons.com/weapons/aircraft/f-16i/F-16I.html:

  Conformal Fuel Tanks (CFT) - These tanks are manufactured by the  "Israel Aircraft Industries"  and increase the aircraft's amount of internal fuel by 50%. Their purpose is to significantly prolong the aircraft's flight range and ability to remain in the air. The tanks are installed the plane's back and conform to it's figure.

Israel does not have any heavy bombers, so they need the fighters to be capable of striking deep in enemy territory and since they can't be accompanied by tankers there, they need additional fuel.

As jwenting mentioned in comment, unlike most conformal tanks that are removable on the ground, these are fitted permanently.


How does an eILS improve throughput (for the A380)?

The bigger the aircraft, the more disturbance it creates to the ILS signal while moving on the runway (or TWY). Therefore airports have static and dynamic ILS sensitive areas to assure the validity of ILS signal. The eILS has smaller dynamic localizer sensitive areas, and aircraft (A380 in this case) will vacate this area in less time, enabling reduced separation and increasing throughput.

A little something about ILS critical and sensitive areas: Determination of ILS Critical and Sensitive Areas - icasc (.pps)


What does "reserve take off" mean in engine parameter documentation?

I've seen this mentioned in story (unfortunately in Czech) about flying in Bhutan on ATR-42 (a smaller version of the same aircraft). Basically in most situation it is recommended to use less then maximum rated power to reduce wear of the engine and that setting is marked as “take off” and the maximum rated power is only used in high density altitude (hot and high) conditions or very short runways and is labelled “reserve take off”.

Most other aircraft don't have setting labelled like this, but taking off at less than maximum rated power is common. It is called “derated” or “flex” take-off.


Can one use a calculator for the EASA part 66 exam?

Calculators are not allowed during examination. Therefore all calculations should be feasible without a calculator. Where a question involves calculations not feasible without a calculator, such as root 10, then the question should specify the approximate value of root 10

I found the answer on page 7 of this pdf.


Does the A320 autopilot work in flight with both engines off?

You want to assume the APU is running. The FCOM says:

APU start is not available for 45 s after the loss of both engine generators. This 45 s delay prevents any interference with emergency generator coupling.

So the APU can be started following dual engine failure after waiting 45 seconds.
With the APU running, the green (G) and yellow (Y) hydraulic systems will also be powered, so AP1+2 should work. (The Y hyd will run via the elec pump on AC2, and with Y pressurized, so will the G via the power transfer unit.)
Descending by maintaining a speed using pitch control is called OPEN DES in an Airbus (FLCH for Boeings). OPEN DES doesn't require the A/THR to be working:

The engine-out descent strategy requires disconnection of the autothrust, and descent in OPEN DES mode.
Disconnecting the autothrust prevents an automatic setting of THR IDLE; therefore, the autopilot will fly the target speed in OP DES mode, with a thrust manually selected by the crew.
When reaching the FCU-selected altitude, or whenever normal descent is resumed to a lower altitude, reengage the autothrust.

The flight law reconfiguration table in the FCOM says the AP is lost when any of the items in the dashed box below fail:

I tried to disprove it, but it seems like with the APU started, an OPEN DES should work. (Report back please.)


How does the canard plan of the Dassault Rafale work?

The answer is in two parts. First, at higher speeds, control surfaces have more air moving over them and so they don't have to angle as much to provide the same force necessary to move the jet as they do at slower speeds. In fact, a thin control surface like this canard will stall at lower angles of attack than a thicker profile would (the thinner profile reduces drag which is why it's used here), and a stalled surface can't do its job.

Second, modern jets like the Rafale have fly-by-wire systems with flight limiters, to avoid the pilot overstressing the airframe at high speeds. The first video shows the Rafale in landing configuration, approaching a carrier at maybe 150kts. The second video shows high-G maneuvers at probably between 300 and 400kts. The forces at play on the canard are, in general, related to the square of the speed of the air moving past them, so if the system allowed the canards to present the same angle to a 300-knot flow as a 150-knot flow, all other things being equal the canard would be under 4 times the stress. At 450 knots that canard would be under 9 times the stress. Very quickly you would exceed the mechanical strength of that canard surface entirely, and then you wouldn't have a canard surface at all. So instead, the canards are moved at a shallower angle, with the difference in pitch rate, up to what the flight limiter will allow the entire aircraft to do, is made up using the elevons on the wings.


What aircraft might have white wing tip lights?

You don't tell us if you're viewing this aircraft from the front (approaching you) or the back (moving away from you), so let's look at all the options:

Aircraft have three colors of steady-burning navigation/position lights: Red on the left (port) side, Green on the right (starboard) side, and White at the aftmost position (tail). This diagram shows the required lighting coverage (as implemented on a typical small aircraft):

(With the exception of a "mast light" these are identical to naval vessel position lights - the function of a mast light is performed by the landing light, though it's not used as a "position light" the way the others are.)

On some aircraft there will also be aft-facing white position lights on the wingtips, combined with the navigation and strobe lights:

The aft-facing position lights on the wingtip improve visibility at night, particularly flying over brightly lit urban areas (a problem sailing vessels don't have). They also give a visual reference to determine the size (wingspan) of the aircraft.

Finally (just to throw another wrench in the works) some aircraft are equipped with wingtip "recognition lights" (forward-facing white lights on the wingtip):

These are typically used on the ground or in approach to landing, but when illuminated the brighter recognition lights can make the forward position lights difficult to see, particularly from the ground where your eyes probably aren't adapted for darkness.

So putting it all together:

If you're viewing the aircraft from the rear (it's flying away from you) you will only see white lights (either one or three white lights) and the aircraft's strobes or other intermittent anti-collision lights. You will thus know the aircraft is traveling away from you.

If you're viewing the aircraft from the front (it's flying directly toward you) you will see a red and green light (possibly with white taxi/landing/recognition lights as well, but the red and green at the wingtips are what you're looking for to identify the aircraft's direction of travel).
Again if the aircraft has wingtip "recognition lights" you may have trouble picking out the navigation lights.

If you're viewing the aircraft from the side (it's flying perpendicular to you) you will see either the Red or Green light until it passes in front of you, at which point one (or more) of the white lights will come into view.


Are large passenger aircraft steered during taxi by changing the angle of the front landing gear?

During taxiing aircraft turn using their nose wheel.

The nose wheel is usually hydraulically controlled. The pilot operates it through a tiller. The nose gear can rotate usually quite far, sometimes to almost 90 degrees.

At high speeds, directional control is achieved using the rudder pedals. The nose gear is often linked to the rudder pedals, however the maximum rotation is limited. The nose gear steering does not exactly match to the the rudder steering at all speeds. At low speeds the rudder is ineffective so the nose wheel steering is dominant. For sharp turns the tiller is always used because of the limited rotation by the pedals.

A320 Nose wheel tiller

B747-400 Nose wheel tiller


What's the minimum number of sensors for a hobby GPS waypoint-following UAV?

The absolute minimum for a generalized vehicle that needs to know its position and attitude (orientation) in space is one per degree of freedom. This can be reduced if we have information about the natural modes of the system and their stability.

For simplicity, let's assume a vehicle moving in 3 dimensions, that means a total of 6 DoF:

3 coordinates in space to know the position
3 angles (or similar) to know the attitude

The simplest way to meet these requirements are accelerometers for the XYZ coordinates and gyroscopes for the angles, and these are often packaged together into an IMU. Technically you don't even need an actual GPS as long as you know the coordinates of the starting location, as you can just integrate from it to know your position. This is known as dead reckoning via inertial navigation and it works this way (let's use coordinate $x$ as an example):

You need to know the initial value $x$ and its rate of change: $x_0, \dot{x}_0$
Listen to the values of the $\ddot{x}$ accelerometer.
Integrate the acceleration to obtain the speed: $\dot{x}=\int{\ddot{x}\,dx}+\dot{x}_0$
Integrate the speed to obtain the position: $x=\int{\dot{x}\,dx}+x_0$

Of course this has multiple shortcomings. Real-world accelerometers have noise, gyroscopes have drift, your starting location is probably inaccurate, your vehicle likely needs more data than that to operate and the whole systems I just described had no way of finding itself if it resets in-mission.

For a realistic barebones project like you described you will need:

3 accelerometers (in an IMU)
3 gyroscopes (in an IMU)
3 magnetometers (usually come with the IMU and help keep the previous 2 in line)
GPS (can be bundled with the IMU and you specifically wanted it)

Further data sources are desirable but greatly complicate the FCS architecture, since you need to properly weight the data, after all, you don't want the aircraft to trust the magnetometer more than the gyros and show you a little trick it learned when passing near a magnetic anomaly.

In particular, a Pitot probe is good to have know your airspeed as opposed to your ground speed. An alpha vane is a bit of a luxury and not needed unless you are pushing the flight envelope.

Any ground-watching sensor with sufficient update rate, range and accuracy (IR, laser, LiDAR, acoustic, etc) will allow you to smooth your landings, and which one you pick should depend on your design and budget; they all have pros and cons.

From the coding standpoint, if you are serious about doing this by yourself from scratch, you should look into real time systems, Kalman filters and the vast field of sensor fusion. Also learn some aerodynamics while at it, so that the airframe itself is not a black box to you. You can run an FCS on an Arduino, even for quadcopters, if you are content with just a basic SAS.

There is a large community of hobby UAV builders online that can provide you with an almost off the shelf solution for your FCS (Ardupilot), if you prefer that approach. I personally often find their documentation lacking, so I suggest you at least learn the basics behind what you are doing, to help you navigate the inevitable gaps in the manual. Also, since it is an open source project, you can then fill in those gaps.


What's the EPNdB for large turbofan engines for stage 5 noise regulations?

What the FAA is calling "Stage 5" is the ICAO Chapter 14 regulations. These do no go into effect until 2017 or 2020, but that means it would be applicable for future engines such as the GE9X.

The cumulative EPNdB margin for Chapter 14 is Chapter 4 +7, or Chapter 3 +17. The exact EPNdB value depends on takeoff weight.


Why this formula says jet engine is efficient at any speed?

This is the result from the simple momentum balance. In order for the propulsor to produce thrust, the exit speed after the propulsing element ($v_e$) must be higher than the incoming speed ($v$):

$$T=\dot{m}(v_e-v)$$

where $\dot{m}$ is the total mass flux through the propulsor.

So the correct way to read the efficiency formula is: the closer the exit speed is to the incoming speed, the more efficient it is! Therefore, the more mass flux you can generate at a smaller speed difference, the more efficiency you can attain without sacrificing the thrust. This is the overarching reason why bypass ratio makes engines more efficient.


How should a glider pilot handle inadvertently entering a foreign country?

How can the pilot make their arrival formal, their stay legal and eventually return to the origin country without problems?

Let others know your plans beforehand. If worst comes to worst you need someone on the other side to try and resolve the issue.

Is there any law protecting pilots in such cases?

Internationally agreed upon law? Not to my knowledge since laws are typically sovereign in nature. (Better ask on Law.SE; someone did ask a related but more specific question, but no answer as of yet.)

All I know is what ICAO recommends in SARPs Annex 9:

  3.72 Recommended Practice.— Contracting States should establish measures for authorizing temporary entry for a passenger or crew member who does not possess the required entry visa prior to arrival, due to diversion or delay of a flight for reasons of force majeure.

Also to my knowledge force majeure cases are few and far between, and handled according to the specific situation. You can't have a law that can be used as a loophole to fake a situation (ideally).

If such law existed, ICAO wouldn't have needed to make a recommendation to its member countries.

Or will they be treated as illegal immigrants?

Could be worse if the diplomatic relations of said two countries are not ideal. The pilot could be treated as a spy, hence, let others know of your flying plans.

I couldn't find a glider story, but balloons are similar, and 1995 saw a tragic incident:

  In an incident recalling the most violent excesses of the cold war, Belarussian combat aircraft have shot down a sport balloon that flew over the border from Poland while competing in a race.

Not just balloons, even jogging can land you in trouble:

  A visitor from France says she was jogging along the beach south of White Rock, B.C., when she crossed the U.S. border without realizing it. So began a two-week nightmare that landed her in a prison jumpsuit.


What is that Boeing 757 custom cockpit interface?


If you're considering going career, skip Sport and Rec; you'll need Private before anything higher, and there's no credit for having anything lower first. But wait until you see how your first few lessons go before getting too far ahead of yourself.


What is this "Micro T-tail" on the F-102?

The T tail is the VHF Antenna Localizer of the AN/ARN-31 Instrument Landing System.

source: Convair F-102 Delta Dagger Pilot's Flight Operating Manual


Why do some commercial aircraft have no landing gear cover?

Yes, it does increase drag.  Anything that is not smooth, where the air flow will be disturbed, will generate drag.

The 737 was originally designed only for short haul and space is at a premium.  Adding doors and all the associated mechanisms adds complexity, weight, additional maintenance requirements and more possibilities for failure.

Boeing have had many opportunities to add doors and have chosen not to; so they, and their customers, do not see the drag penalty as more expensive than the extra weight and maintenance.


How to lean with constant speed prop on multi-engine aircraft without EGT

There is a big difference between "by feel" leaning of a carburated vs fuel injected engine.  Carburated engines have less even fuel distribution and when leaning, one cylinder, the already leanest one, will start to misfire quite a bit before the others.  So with a carb it's easy to detect one cylinder starting to misfire (the cylinder usually doesn't totally quit right away - you will pick up random misses in the vibration rhythm).

With a fuel injected engine the mixture distribution is more even and misfire of one cylinder will be accompanied by misfire of its sisters almost immediately.  So on an injected engine you will lean and suddenly the engine will really start to stumble, whereas with a carburated engine there will just be these random dropouts in the engine's "beat", getting worse as you continue leaning.

So if you are leaning on an aircraft with fuel injection it is really fairly straightforward.  The engine will go from smooth to pretty rough right away, whereas with a carb it takes careful attention to detect the early onset of misfire. You are at a disadvantage to some degree because the airplane is less familiar than to the instructors.  It's a skill you will pick up over time as you develop at ear for it.

Don't worry too much about it. Err on the side of smoothness, knowing that the difference in fuel consumption between perfect and good enough is negligible (and if you're paying hourly on a hobbs meter, there is no benefit to you anyway), and it's wise to err on the side that is beneficial to the engine (too rich).


How does density altitude affect performance, temperature, and pressure; and how is it calculated?

The International Standard Atmosphere (ISA) gives “average” values of air pressure and density by altitude. It starts by defining standard pressure 1013.25 hPa (29.92 inHg) and standard temperature 15°C at sea level, and derives the values for higher altitude from physical laws.

A “density altitude” is altitude in ISA at which air has the density you are observing. This is analogous to “pressure altitude”, which is altitude in ISA where the pressure you are observing occurs.

You can measure pressure altitude easily by setting your altimeter to the standard pressure of 29.92 inHg/1013 hPa. However you don't have any instrument to directly measure air density, so you have to calculate density altitude from pressure altitude, temperature and humidity.

  And why 8300 ft specifically? Was it calculated? If so, how?

This AOPA document provides approximate formula:

  Density altitude in feet = pressure altitude in feet + (120 x (OAT - ISA temperature))

  Pressure altitude is determined by setting the altimeter to 29.92 and reading the altitude indicated on the altimeter.
  OAT stands for outside air temperature (in degrees Celsius).
  ISA stands for standard temperature (in degrees Celsius).

  Keep in mind the standard temperature is 15 degrees C but only at sea level. It decreases about 2 degrees C (or 3.5 degrees F) per 1,000 feet of altitude above sea level.

I have also found a calculator, which uses more accurate equation, also taking humidity into account. It comes with detailed explanation of the physics involved.

Giving it current METAR FAGM 301600Z 33006KT CAVOK 27/00 Q1022 it calculates density 0.967 kg/m³, which is expressed as density altitude 7 866 ft (2 397 m).

It's already late afternoon, so earlier in the day it might have even 8 300 ft (if it was 31°C, which might have been just past noon)

  What does the 8300 ft mean in terms of air quality?

It is simply another way of expressing the density 0.954 kg/m³. You are normally familiar with how the performance decreases when you climb, so expressing density as altitude allows you to easily reference the loss of performance due to the hot weather to that.

  What does the 8300 ft mean? Does it mean that at that altitude, aircraft performance will be at its lowest?

It means aircraft performance will be as if you were at 8 300 ft on a standard day.

Both aerodynamic and engine performance depend on density. For aerodynamic performance higher density altitude means you'll need higher true airspeed for the same indicated airspeed, and for engine higher density altitude (lower density) means lower maximum power.

For an average single-engine piston aircraft, 8 300 ft is quite high. The performance will be poor.


What are the operational limitations on ADS-B DO-260A (as compared to DO-260B)?

If the aircraft is subject to the ADS-B mandate of Europe, it will not be allowed to operate in European airspace after June 7, 2020 if it does not have a certified EUROCAE ED-102A (equivalent to RTCA DO-260B) compliant ADS-B transmitter. Aircraft with a maximum take-off weight exceeding 5700 kg or maximum operating true airspeed exceeding 250 knots are subject to the mandate.

The USA rule is a bit different, as it allows ADS-B on universal access transceivers (UAT) below 18 000 ft which is different from the 1090ES technology used in DO-260. You can do without ADS-B in the USA after January 1, 2020, if you never fly higher than 10 000ft MSL (exceeding 10 000ft MSL is allowed as long as you don't exceed 2 500ft AGL), you do not enter or overfly class C airspace and keep further than 30 NM from class B airspace.
If your aircraft is 1090ES ADS-B equipped it must be DO-260B compliant; if it UAT ADS-B equipped it must be DO-282B compliant.

The difference between DO-260A and DO-260B are many small changes. This list is not exhaustive:

change in the way position integrity is encoded,
addition of barometric pressure setting,
new encoding aircraft length / width
change in encoding of speed on surface

Typically the update from DO-260A to DO-260B requires a firmware update and some configuration changes. However, note that the mandates include more requirements than just the ADS-B protocol version. There are requirements on the integrity of your position source (GPS) as well, and the maximum latency in the position transmission chain. In the worst case you are up for a rewiring of the GPS or even installing a new GPS.


What is the risk of icing with water / moisture on wings prior to takeoff?

Taking off with wet wings is not a problem, the airflow is going to blow the water off long before it reaches the freezing point. There's no concerns here.

Given the scenario what I would be concerned about would be ice elsewhere on the airframe. 40°F (4°C) could mean that the aircraft was frozen overnight, and there could be ice left over where the sun didn't melt it off. That kind of ice wouldn't necessarily impact the airflow on the wing, but it would make the airplane heavier and therefore impact performance. A simple visual check on the walk-around will confirm this. If there is ice left then deal with it even if it's not on the wing or tail, if it's just wet then get in and fly.


How could a twin aisle aircraft (Boeing NMA) ever have a single aisle (A321) economics?

So it's definitely not ALL marketing spin, but it's also definitely not ALL engineering, either.

The frontal area is absolutely a major component of the drag on an airplane, but wingtip devices (sharklets, winglets, etc.) can significantly reduce drag, as can better nose shapes, smoother surfaces, and a number of other design considerations.  If you kept all these other things the same, then increasing the frontal area would increase drag and reduce efficiency, but these other things aren't the same in a new airplane.  The MoM proposal would certainly take advantage of all sorts of wing, engine, airframe design improvements that would reduce the drag components, and then you'd gobble most if not all of that up by making the airplane wider.  ;-)

If I'm putting on my "engineer but worked in marketing for a while" hat, I'd say that the challenge put to me is that the marketing people want an airplane that can be operated at what used to be called single-aisle efficiency, but can now be done with widebody seat capacities.

I'd also contend that of the parameters mentioned: "range, comfort, capacity, and faster turnaround time" the only one of those things that really requires you to think seriously about a twin-aisle airplane is capacity.  I can build a single-aisle aircraft that has every bit as much range, way more comfort, and a much faster turn around time as a twin-aisle aircraft, it just doesn't hold as many people.  ;-)


What are some common factors that affect GA aircraft manufacturability?

This answer can only scratch the surface - a good answer would take you several days to read.

Manufacturability is the combination of several things which combine to

improve the repeatability of the finished products without much individual reworking, and
reduce the work hours required to produce a given component or system

under the local conditions (wage level, worker skills, energy prices, logistics etc.). This list of factors is incomplete but should give you an idea what is involved.

This is done by selecting the proper techniques (lots of jigs and molds for repeatability, the fewest amounts of parts and joints for reducing man hours) and by designing the system such that producing the components and combining them into the finished product can be done quickly and with the available workforce.

An example: When Fairchild joined up with Dornier, they planned to relocate the production of the Do-328 from Bavaria to Arizona. The production line in Germany was set up for the local workforce, and since they were highly skilled metal workers, the holes they drilled manually were straight within ±2°. In the USA, however, Fairchild could not find enough adequately trained workers, so the production line would had needed jigs for every single hand-drilled hole - and there were lots of them on the 328. The whole endeavor floundered because the production line was not designed for manufacturability under the new local conditions, and remedying this would had cost too much.

Another example would be the Tu-4. This was a Russian copy of the Boeing B-29, which the Russians had ample time to study after some landed in Eastern Siberia after attacks on Japan. But it was no cheap knock-off: The Tupolev design bureau redid the design, airframe, engines, systems and all, in metric dimensions, so standard Russian gage sizes, fasteners and tools could be used. It was re-designed for manufacturing, in other words.


Why the pitot tube is heated but the static port isn't?

Some aircraft DO heat the static port, if only by side effect: Piper PA28 aircraft (Cherokee/Warrior/Archer/Arrow ) for example have the static port located on the pitot mast.  When pitot heat is turned on in these aircraft the entire mast heats up, including the static port.
This characteristic would be the same on most aircraft with a combined pitot/static mast.

As for why most light aircraft don't heat the static port, there are two big reasons.

First, as you've heard, static ports are normally not located in areas susceptible to icing -- they're on the side of the fuselage in areas of relatively undisturbed air (on most of the Cessnas I'm familiar with they're forward of the doors, on other aircraft they're right around where the registration numbers get painted). As Falk pointed out this means ice normally won't accumulate there.
As an additional protection some aircraft have multiple external static ports (connected to a shared static line) so that if one port does get iced over you still have a source of reference pressure.

Second, a static failure is relatively easy to deal with - particularly in unpressurized light aircraft.  Many unpressurized aircraft that are regularly flown in instrument conditions will have an alternate static source in the cabin (which is simply a valve that opens the static line to cabin air), or the traditional "break the VSI glass" solution can be used to get a mostly-working altimeter.


Does the flight always switch to TRACON on a go-around in class B airspace?

It depends. As a rule oh thumb, a missed approach will be handed over to approach (TRACON) to get a new approach clearance. Some places have local rules that allow approach to delegate this responsibility to the tower when it makes sense, which means the aircraft can then stay on the tower frequency for the new approach. This would normally require a few things, such as appropriate equipment being available in the tower (radar) and having a tower controller that is actually rated to be allowed to perform approach control.
In any case, when a go around is initiated, the tower will immediately call approach and coordinate what to do. One of the results of this coordination is the "heading and altitude" you have heard the tower give to some flights. Typically, approach will request to get the flight at a specific heading and altitude, and the tower will give those instructions before handing over the flight. Some airports will have very specific local regulations about which steps to follow, others allow the controllers to come up with a solution that fits the specific situation.


Which aircraft is a single-prop, low-wing aircraft with prominent rivets and three canopy windows?

When I saw your daughter’s drawing I thought of the Vultee P-66 “Vanguard”.

But the Republic P-47 “Thunderbolt” might also be a good candidate.


What does "MERMA" mean on the Los Angeles TAC chart?

MERMA is an aviation waypoint

  Waypoints used in aviation are given five-letter names. These names are meant to be pronounceable or have a mnemonic value, so that they may easily be conveyed by voice.

According to this page back before the FAA decided all waypoints must have 5 character names, this waypoint - being out in the ocean - was called "Mermaid" and after renaming this became simply MERMA.


Do autopilots force the aircraft to fly over certain coordinates?

Over the North Atlantic, there are no predefined low-level or high-level airways as there are over the continents. In order for aircraft to get a tailwind for eastbound flights and get out of the wind for westbound flights, Canadian and UK air traffic control set tracks based on the expected wind conditions twice a day.

The lines you are seeing are called an 'Organized Track System'; is this part of the world, they're called 'NAT' (North Atlantic) Tracks. Five to six roughly-parallel tracks will be defined and move around every day, but they will generally go between whole degrees of latitude and 10° increments of longitude.

For example, tonight's (Dec 31/13) track BRAVO ('B') will go from a intersection in the UK called...

ERAKA (at 58°N/10°W) to
60°N/20°W to
61°N/30°W to
61°N/40°W to
60°N/50°W to
MOATT (at 58.025°N/59.928°W) to
LOMTA (at 57.203°N/62.619°W).