How do I know if I'm able to use LPV minimums on a GPS approach?

There are many websites / blog pages that compare and contrast the different approaches. All you need to do is google a bit.

That said, if your plane can fly LPV approaches you'd know that. It requires WAAS-quality GPS receiver, and to install that requires at least a logbook entry.

Note that it's not only a matter of equipment. Even when the plane is equipped to fly LPV approaches, there can be certain conditions when you can't use LPV minimums (satellites, etc.) If you CAN use LPV minimums, the GPS unit MUST show you "LPV" in the annunciator window. It's possible that you're LPV-equipped, but your annunciator window shows you only "LNAV", for example.

So, check your documents, talk to your mechanic, you wouldn't really NOT know if your plane was ever upgraded for LPV approaches. If it's your own, you'd know and have discussed it and most likely given the mechanic the task to upgrade it. If it's a rental, or you're just buying it, look at the logs and ask the seller. And keep in mind, the annunciator window will show you the lowest GPS approach type that it senses is safe. Usually on an LPV-equipped plane that will be "LPV", but it's entirely possible it will only show "LNAV", or something else. For you to use LPV minimums also depends on the actual flight condition.


What is that round antenna(?) on the bottom of a Piper Comanche?

From a Comanche parts catalog, it's the ADF loop antenna (item 45) minus the aero cover (30):

http://www.aeroelectric.com/Reference_Docs/Piper/pa-24-180-250-260-400_pcv1998.pdf


A330 flown by low cost airline - is 8 cabin crew really all they have?

The number of flight attendants required on flights are mandated by international safety regulations. For planes with up to 19 passenger seats, no flight attendant is needed. For larger planes, one flight attendant per 50 passenger seats is needed.—Wikipedia

Eight cabin crew is enough. 377/50 is 7.54.


Why don't rudders stall at 30 deg deflection, as they don't have downwash to reduce local AOA like flaps and horizontal tails do?

At an extreme deflection (like 30º) a rudder is probably stalled. But in that condition, lift does not entirely disappear, and drag increases a lot. The resultant of the two forces (the 'aerodynamic force') pushes the tail sideways, yawing the airplane. Hence, that stall doesn't matter much...


As far as the tracking on aviation websites goes, no you cannot, at least not with the drones or UAVs available for leisure activities.

In order to track these devices they would either need to be equipped with FLARM or a transponder with Mode-S, which again would require a registration.

Unless you have fitted a GPS transceiver to your UAV which offers online tracking via the vendor's website, you will be unable to track UAVs.

Related:
How do you track and visualize aircraft from home?
Why do helicopters not appear in flight trackers?


What is the typical cruising altitude for a civil airplane?

I think there are already plenty of answers here to give you a clue:

How do pilots decide what their cruising altitude will be?
why are regional cruising altitudes higher than those of international much longer flights?
How can you find the best altitude for range or speed?
Why are many jet aircraft designed to cruise around FL350-370?

Normally, atitude restrictions give a top limit. A minimum altitude is hard to enforce when one engine fails - then the aircraft can only continue at a lower altitude (typically around 15,000 ft for a two-engined jet) or the cabin pressurization fails (now the aircraft needs to continue below 10,000 ft).

This is speculation, but maybe the 26,000 ft limit is caused by information that rebels in the West Sinai have gotten hold of shoulder-launched anti-aircraft missiles. Those have a fairly low upper limit to their effectiveness.


What drives N1 during a jet engine start?

N1 is driven by the starter flow through windmilling. N2 is started through a gearbox as described in this answer, driven by an air starter or by an electric motor. This causes air to start flowing through the engine, and the LP turbine blades pick up energy from this airflow.

Above graph is from The Jet Engine by Rolls Royce, and shows that the LP spool (N1) starts to turn in the dry cranking (starting) phase, after N2 has been accelerating for a while. The speed with which N1 spools up depends on the engine type, but even the large inertia of a helicopter rotor is slowly starting to be driven around by the starter flow.


Is a destination airport necessary for cross-country VFR departure clearance?

Just say direction of flight.

If they need more info, they'll ask:

  N12345: Say destination.

I've almost never heard that, except if they think you might be headed towards weather or a TFR.

Examples:

  Understand you're headed to the south.  Be aware of Stadium TFR in effect.

or

  Understand you're headed to the south; have had reports of severe weather in that direction.


Can a paraglider rescue chute and its pilot handle terminal velocity?

I have been told in person by the owner of High Energy Sports, a well-known manufacturer of hang gliding / paragliding emergency parachutes, that their products are not designed to be safely deployed at the terminal velocity of a falling human being.  Regardless of what some particular standard might suggest, I doubt that any hang gliding or paragliding emergency parachute is really designed to have a robust safety factor in the context of deployment in a true terminal-velocity freefall.  The greatest concern would seem to be catastrophic failure of the parachute and/or harness, not injury to the user due to opening shock, but the latter would seem likely to be a possibility as well.

Keep in mind that a hang glider or paraglider pilot does not actually cut away from the rest of their equipment (e.g. the main canopy of a paraglider) before deploying their emergency parachute.  There is no way to easily do so.  And that is why the reserve parachute is not designed for a terminal velocity freefall.  (Edit: see other answer for an exception-- apparently some paragliding rigs are designed to allow for a cutaway.)

Nonetheless, in an article in "Hang Gliding" magazine from well over ten years ago, well-known test pilot Mark Stucky described an incident from his younger days when he went skydiving using his hang gliding emergency parachute.  I don't recall whether the article specified how long he waited before opening the parachute and whether or not he might have been anywhere near the maximum terminal velocity of a falling human being-- one would tend to assume not.  He did survive without injury.

See also answers to related question Whats the difference between a paragliding rescue chute and a parachute?


Why don't the US Navy Blue Angels fly Super Hornets?

The USN Blue Angel demonstration team is transitioning to Super Hornets. According to this press report:

  “We are supporting the Navy’s plans to transition the Blue Angels to Super Hornet aircraft from classic Hornets by providing engineering for the necessary conversion modifications. ...,” Paul Guse, a spokesman for Boeing, said Thursday in an emailed statement.

The transition will take some time for carrying out the necessary modifications including...

  ..., installing flight auxiliary fuel pumps that can operate in sustained inverted manoeuvres and inserting an oil pump in the tail to emit blue smoke.

...among others. Also, as the aircraft performance is different (the Super Hornet is larger and heavier, for one thing), the aircrew will have to train on the new aircraft before participating in any airshows.

A lot of the weight difference may be handled by removing the combat hardware but the size and handling characteristics will require a lot of training and practice time before the super hornet can be used in the precision flying exercises used in air shows.


What is this scoop found on the core of a PW1127G engine near the CC/turbine section?

That scoop allows air to go through the Engine Air/Oil Exchanger which cools the engine oil with fan bypass air.
Engine oil that is cooled by the air/oil heat exchanger decreases the quantity of heat that must be moved from the oil to the fuel in the fuel/oil heat exchanger.


How do I "sightsee" in a class Bravo airspace?

Just call up ATC on the approach frequency and request flight following to see the location you're interested in.  They'll assign you a transponder code and any restrictions.  For example:

  N12345: "Houston approach, VFR request for Cessna 12345"

  Houston TRACON: "Cessna 345, say request"

  N12345: "Cessna 12345 is at 1200 ft, 3 miles south of Houston Executive, requesting flight following to overfly the Greenway Plaza area for sightseeing, aircraft type is a Charlie 172 slant Golf."

  Houston TRACON: "Cessna 345, squawk 4123."

  N12345: "squawk 4123 for Cessna 345"

  Houston TRACON: "Cessna 345, radar contact. Cleared into Bravo, maintain at or below 3,500, remain north of the University, advise when your sightseeing is complete."

  N12345: "Cessna 345 is cleared into Bravo. Will remain at or below 3,500 and north of the University. Will advise when complete."

Notice that it is preferred that you don't give your entire VFR request in the initial callup to avoid overwhelming the controllers if they're busy or not yet prepared to copy your entire request.

Just ask for "VFR request" with your callsign and wait for them to ask for the details.


Do noise abatement procedures have an impact on aircraft emissions?

Generally, it is most fuel efficient - when considering fuel for the whole flight as opposed to individual flight phases - to climb to cruise altitude as quickly as possible (i.e. using maximum thrust), since the aircraft flies much more efficiently at cruise altitude than at lower levels. This is in direct contradiction to anything to do with close-in noise reduction (i.e. around the airport), but it would reduce total flight emissions (other than noise).

For noise further away from the airport, climbing with maximum thrust may actually be more beneficial, as there is another tradeoff between noise emitted at the aircraft and the altitude achieved at the noise sensitive area (quiet can mean passing with low thrust or at high altitude).

So, yes, by altering the climb profile, the emission profile for the flight is altered. The noise abatement procedures will often lead to higher emissions than could be achieved theoretically (not necessarily practically though).


Does an RMI show true or magnetic north?

In a typical installation, the compass card of an RMI indicates magnetic north.

While it is possible to switch that reference on an EFIS display to true north by applying the local variation, that is not the common practice. If you see a "steam gauge" RMI (i.e. not a digital display, but a mechanical compass card) in a panel, chances are excellent that the compass card is slaved to the same heading source as everything else -- magnetic north. In the exception cases, that source can be switched between true & magnetic, but that's uncommon.


Is it worth reporting that I saw a green laser being pointed at the aircraft as a passenger?

In that case I would definitely report the incidence!  It doesn't have to be done by police, but you can give the airport authority a call, that way you don't have to make too much of a big deal about it, and still informed the ones that need to know. They can then advise pilots and keep their eyes open for it. If there is a attack on the airplanes, it is important that it is being reported before it is too late. If not, then you didn't make a big deal out of it and are not in trouble for wasting time and money.

So, a call where you could explain what you have seen and give a opinion is your best bet, if they tell you off then hey, you've tried it!


Why is ISA Standard pressure 1013.2 not used for contour charts instead of QFF?

Maps and charts show true elevation, meaning tape measure altitude from the sea level. The way the mapmakers and chartmakers measure elevation has changed over time. Currently, I think GPS is prevalent. The way GPS computes elevation is depend on the WGS84 Geoid earth model. This modes surface does not coincide with actual sea level but GPS takes that into account. And today in most aeronautic related industries WGS84 is becoming a standart, which also includes maps and charts.

On the other hand altimeter provides height using pressure of air. QNH and QFF are the altimeter settings used to adjust for non-standard pressure and temperature, respectively. QNH is always provided to pilots and is the most prevalent. I have never heard that the QFF is used or requested by pilots.

As I said QNH setting only corrects for non standard pressures. It really assumes ISA temperature, 15C. So as you asked what happens if the temperature is not standard. Well someone needs to compensate for that and make correction.

Colder than ISA temperatures needs to be corrected for minimum enroute altitudes and obstacle clearances. Because the aircraft will be at lower true altitude than what altimeter shows, at colder temperatures. As for hot days, it’s less risky because aircraft’s true altitude will be higher than what is shown on altimeter. Only example comes to my mind is when you’re shooting an approach that has decision altitude kind of minimums. Since the aircraft will be higher than true altitude you may end up going around during real minimum IFR situations. However you will be on the safe side at hot temperatures, in terms of obstacle clearances.

As mentioned in that article; correcting minimum sector altitudes (MSA) and minimum vectoring altitudes for non-standard temperatures are ATC’s responsibility. In other cases, such as doing a published approach, it’s pilot’s responsibility.

That same article provides an excel at the end to use on the ground. Also some pilot operating handbooks provide charts to apply for altitude adjustments for non-standard temperatures. One technique for flight planning is to find the correction for the coldest temperature for  the day and apply that to whole flight. But that applies only to GA type flights really.

Not only that,  but also, there is this phenomenon called geopotential altitude. It implies that 1 altimeter-measured-feet at sea level is not equal to 1 altimeter-measured-feet say at 30,000 feet. And that’s because gravity is not constant as we climb. So the actual true elevation of the obstacle will always be slightly higher than what you see on your altimeter even when you’re side by side. However it’s really a small difference (less than 1%) and not a big factor at low altitudes where obstacles mostly live. [wp reference]


Do commercial jets ever make 360 in the pattern for separation?

Yes, it can happen, but it's pretty uncommon.

Airliners arrive at the destination airport having been sequenced by ARTCC ("Center") and Approach so that they are showing up in an orderly sequence, spaced out so that there is adequate room between them.  They may be set up for an ILS, or they may see the field and accept a visual approach, but either way the flow is generally quite predictable and orderly.  VFR traffic, by its nature, is less controlled and ordered, so it's more likely in that sort of an operation that you'd have two aircraft in positions to arrive at the runway at about the same time, so a solution like a 360 on downwind or on final becomes necessary.  With a flow of airliners (and other IFR traffic) spaced out at 3-5 miles apart, that solution would create as much trouble as it would solve, because now the conflict is with the aircraft behind the one that circled, rather than with the one in front of it.

What does happen more frequently, is the 360 happens much farther out from the airport, and that's called "going into holding" due to traffic saturation.  Maybe the airport is over-loaded with arrivals, or it had to suspend operations while the active runway was changed from 18 to 36 (or whatever they are at a particular field), or there is weather affecting the approaches which slows down the rate at which it can accept arrivals.  The Approach and Center controllers will work to keep the flow of traffic coming into the airport neat & orderly, which means delaying aircraft before they get to Tower's airspace (i.e. the "traffic pattern").  Ideally, they will do this with speed adjustments to get the desired interval, but sometimes the delay needed is more than speed adjustments alone can accomplish.  Then they'll put the arrivals into holding for however long it takes until they can start sending them in again.

That's the more common airline version of a "360 on final"... doing 360's with 10 mile legs on a really, really extended final -- 100+ miles out!

In the case of a go-around that turns downwind, rather than a 360 on final, the typical solution would be to extend turning final out until there is adequate space.  Staying on downwind past a 5 or 10 mile base & final is highly undesirable for a VFR pattern, but for airliners where everybody has an ILS and doesn't really have to maintain sight of the runway, it's no big deal.  For big airports, extending the traffic pattern out to longer finals is highly preferred over having jets circling on final.


Usually, the clearance is given when the runway is clear of traffic or, at least in Europe, when two conditions are met:

Reduced Runway Separations is in use and the criteria for issuing the landing clearance are met.
The previous traffic will have left the runway when the following aircraft crosses the threshold. (Non-withheld landing clearance)

  321.5 Landing clearance need not be withheld until prescribed separation exists
  if there is reasonable assurance that the appropriate separation will exist
  when the aircraft crosses the runway threshold. However, do not clear an
  aircraft to land before a preceding landing aircraft has crossed the runway
  threshold.

Aircraft can also be made aware to expect a late landing clearance.

Clearing multiple aircraft to land in a sequence on the localizer is not used in countries operating under ICAO rules. This is more of an FAA procedure, as described in the other answers.


Could Malaysia Airlines Flight 370 have sunk without leaving any floating wreckage?

Yes, but only under highly unlikely circumstances.  An airplane contains all sorts of materials that float, from fuel to seat cushions to the plastic cups in the galley.  In order to sink without leaving any floating wreckage, all of that material would need to be trapped within the airplane while it fills with water.

In order for this to happen, the airplane needs to land intact on the water.  As any number of ditchings indicate, this isn't going to happen -- even US Airways 1549 had the rear of the fuselage tear open on landing.  More often, the engines or wings will tear off, leaving oil and fuel slicks.


How is a fly-by-wire system realized in big planes?

In fact, ARINC 429 is used in the "federated" avionics, this is the "old" system used in many aircraft like A320, B737, ...

Federated avionics require a lot of wires which generates a lot of weight. In ARINC we have approximately one wire per device, so the speed (100Kbps or 12,5Kbps depending on the selected mode) is sufficient.

ARINC 429 Architecture :

In "new" aircraft like A350 or B787 the industry use the Integrated Modular Avionics in order to reduce weight and reduce the number of S/N to stock.

In this kind on avionic all computers are merged in a couple of "cabinet" composed of multiple core processor units, shared ROM, shared RAM, shared graphic cards.
All these cards are linked, in the cabinet, with the Backplane BUS (ARINC 659), which operates at 60Mbps as a commercial aviation bus
All cabinet are linked ,each other and with actuators, using AFDX (ARINC 664) who look like Ethernet protocol and work at the speed of 100Mbit/s.

There is a lot of different IMA architecture with the same principle, but some differences. This is one on them, in this picture you can replace PCI Ex. by ARINC 659 :

Regarding CAN bus, Airbus use in in this A380 (http://www.aviationtoday.com/av/issue/feature/can-bus-in-aviation_31468.html)

Sources :

http://www.interfacebus.com/Design_Connector_Avionics.html

http://www.modern-avionics.com/

https://en.wikipedia.org/wiki/Avionics_Full-Duplex_Switched_Ethernet


Did we get closer to another plane than we were supposed to, or was the pilot just protecting our delicate sensibilities?

From the flightradar24 playback, it appears to have been an encounter with Etihad Airways 171.

Your flight (Alaska) was at FL360, while the opposing was at FL370. Therefore, there was 1000 feet of vertical separation between them, which is typically considered safe when operating with RVSM, Reduced Vertical Separation Minima rules (see other answers).

I also looked up the LiveATC recordings archive (Seattle Centre Sector 14 high, 28/04 2000Z), and found a clip that I think corresponds to the event:

  Alaska 557, can we take a heading right of course to avoid some wind?
  Affirmative
  Ok, deviation approved [...]


Do all airports have the authority to impound aircraft for overdue fees?

Yes, at least if the airport is city owned (or owned by a municipality). For example Philadelphia's airports are city owned and they have landing fees as well as default repercussions

  1.05. Payments

  Non-tenant Air Carriers and Operators not providing adequate surety or
  security in form and amount satisfactory to the Department of
  Commerce, to ensure payment of fees and charges, shall be required to
  pay all incurred fees and charges prior to aircraft departure.

  ...

  If any charges remain unpaid for a period of twenty (20) days after the due date,

  the City may:

  a. Bar operator from the Airport and
  the use thereof; and/or

  b. Deny operator the use of Airport
  facilities; and/or

  c. Commence such actions at law or in equity as are
  deemed in the best interests of the City.

I see no reason impound would not be covered under section C there. Privately owned airports are a different situation but I imagine they have some kind of legal recourse.


Do planes return to service after non-fiery crashes?

If the aircraft can be economically repaired (there is no major structural damage, and we're not talking about an aircraft already scheduled to be retired) then it's likely the aircraft will be repaired and returned to service. When you spend several million on an aircraft you aren't going to throw it away for a few tens or hundred thousand dollars worth of damage, particularly as it's probably insured.

If the aircraft is structurally compromised to the point where repairs would not be economical (or if we're talking about an older aircraft which has given many years of service and is due for retirement) it would probably be written off and scrapped for any salvageable parts (either repairing it to a condition where it could be ferried to a "boneyard" or dismantled and cut up at the accident site - whichever option is less expensive for the airline).

As one particularly famous datapoint, the Gimli Glider had an off-airport landing with a nose gear collapse in 1983. The aircraft was repaired, returned to service, and flew until 2008 (a little under 25 years of additional service after its incident).


Why didn't the Boeing 757 share the 767 fuselage?

Boeing had already a fuselage for the 757 that fit the bill. It came originally from the 707 via the 727. To accommodate more baggage, the rear fuselage was deeper, as on the 737. During development Boeing engineers were afraid that directional stability might be insufficient with a deeper forward fuselage, so the lower half of the fuselage was kept from the 727 instead of switching to the deeper fuselage of the 737. A twin-aisle fuselage would had restricted the possible variants with fewer seats too much.

From a contribution by OldAeroGuy to this discussion on Airliners.net:

  The 757 entered design using the 727 fuselage as baseline as it was
  originally a 727 derivative, so it had the 727 dimensions for fore and
  aft lower lobes. It was later decided to evaluate a deeper forebody
  lower lobe, ala the 737. The forward fuselage cross section decision
  was made to meet a manufacturing commitment before all wind tunnel
  testing was complete. Early indications were that if the deeper lower
  lobe was used for the forebody, directional stability would have been
  reduced to an undesireable level. When all testing was finished, it
  was shown that a deeper forward lobe would have been OK.
  Unfortunately, it was too late to revise the manufacturing plans.

  I was a member of the wind tunnel testing team at the time the 757 was
  being developed and was aware of the situation. After the 757 was
  certified, I asked the 757 Chief Engineer what design decisions he
  would like to change with the benefit of hindsight. The forward lower
  lobe decision was the first on his list.

A wider and higher fuselage causes more drag directly but will also require a larger tail surface because of its shorter length, causing more mass and drag indirectly. Note that the Airbus A318, the shortest member of the A320 family has a taller vertical tail than all other members. Using the slender fuselage and the RB-211 engines made the 757 very fuel efficient, which was very important for Boeing just after the second oil shock of 1979-1980. A larger fuselage would had reduced efficiency.

From this Aviation Week article:

  A single aisle worked better for the lower end, but did not stretch
  very well. A twin aisle worked better for the upper end, but equally
  did not shrink well. As a result, for almost six years in the 1970s,
  the company exhaustively studied two concepts: a single-aisle twin
  dubbed the 7N7 and a widebody twin called the 7X7.

  Most observers at the time believed Boeing would develop one or the
  other but not both, at least not immediately. It was therefore with
  some surprise that between 1978-79, over a period of less than eight
  months, the company ambitiously began the simultaneous development of
  both aircraft. The 7X7 became the 767 in July 1978, while the 757,
  formerly the 7N7, received the production go-ahead the following
  March.


Is there any way we can predict an air crash?

Yes, many aircraft are fitted with TCAS which predicts one type of crash - an aerial collision.

Many aircraft are fitted with GPWS which predicts another type of crash - controlled flight into terrain.

The ground based ATC have systems that predict a loss of separation, the Short-Term Conflict Alert [STCA]. See this question about separation and conflicts. In terms of predictions this would constitute a very high rate of false positives. But that is good.

Because of the predictions, many crashes are avoided.


How do flight procedure designers decide when to assign an altitude constraint to a waypoint?

Altitude limits on these procedures have to take many different things into account, including obstacle clearance and communication, but also radar coverage, separation from other procedures and airspace, the overall profile of the procedure, noise abatement, and more.

The at or above 2500 restriction on the DEEZZ is similarly included in the other SIDs at KJFK. The main reason could be that the NYPD operates helicopters out of Floyd Bennett Field below that area, and the Jamaica Bay seaplane base is also nearby. Another reason could be to keep aircraft above the approach for runways 4L and 4R, though I'm not sure they would use those at the same time. It could also help noise abatement for the homes and parks in the area.

In the case of the HAWKZ, my guess on the altitude restriction is to keep all the aircraft on those segments at approximately the same altitudes. It seems like an aircraft could be lower than FL220 at PTERA without other issues, but the lower an aircraft descends, the slower it flies, and it would become difficult to work a slower aircraft in with the faster stream of traffic at the higher altitude. This sort of restriction is not uncommon on STARs that begin relatively far out.


What would happen if someone covered a small hole in the fuselage of a plane with a soft body part?

I assume the hole has been properly deburred, otherwise you could suffer cuts on the sharp edges of the hole.

What happens else depends on altitude and flight speed.

At low level, the outside temperature should be tolerable and the pressure difference between inside and outside should be small, so your hand will be fine.

At higher altitude, outside air temperature can drop to -60°C rsp. -76°F. Since air density is lower, the aircraft will travel fast (approx. 250 m/s rsp. 560 Mph in case of an airliner), and convective cooling at the hole will soon cause hypothermia and frost bites. Also, inside pressure is 0.6 bar rsp 8.8 lb/sq-in higher than outside pressure, and the exposed skin on your palm will feel this as a sucking sensation.

I further assume that you need to remove all cabin insulation to put your hand over that hole, so your whole hand will be exposed to the airplane's metal skin which will have the same temperature as outside air. If the hand is dry and does not freeze to the metal skin, you might manage to keep it in place for a few seconds, but it will hurt. Keep it in contact with the metal skin longer and you will suffer progressive frostbite. The part of the skin which covers the hole should suffer less, since convective cooling should be less intense than the thermal conductivity of the metal skin, which will quickly pull all body heat from your hand where it touches the metal.

The pressure difference will not damage your hand, but the low temperature will.


How many zig-zag patterns are there in a dog tooth leading edge?

Both terms (“zig-zag” or “dogtooth”) designate the same leading edge aerodynamic design, and are used interchangeably. “Saw-tooth” is also used to indicate the same leading edge pattern, yet it is also used in naming a specific trailing edge design (a “saw-tooth” trailing edge; see this paper which explores this effect: Saw-tooth, or, Serrated trailing edge
The number of “cuts” (or, extrusions of the leading edge of a certain wing section compared to the leading edge towards the root of the wing) are a choice of design.
The “dogtooth” (or “sawtooth”, or “zig-zag”) at the leading edge acts in a way similar to a wing fence ), inducing an effect on the relative airflow which acts to prevent span-wise flow (and also adds energy to the air flowing over any control surface in the area, increasing its effectiveness.
As there are aircraft with numerous wing fences, so can the dog-tooth extrusion be multiplied on each wing, however, it is a question whether there were any planes out there with more than three such points of extrusion.
See this question for more detail: Hawker Hunter Dog-tooth wing - Aviation SE
Take a look at these pictures: notice the “dog-tooth” / “saw-tooth” leading edge and “saw-tooth” / “serrated” trailing edge.


what are the Common roll angle and roll rate limits for civil flights?

The minimum roll rate is documented in 14 CFR 23.157 (pre Amdt 64), which is used as an accepted means of compliance for the current 14 CFR 23.2135.

As far as I know, there is no regulatory requirement on maximum roll rate. For large transport aircraft, the design target at maximum roll authority is typically around 20 deg/s to 30 deg/s. For example, A320 has a roll rate limit of 15 deg/s at maximum lateral input in Normal Law, while A220 has a roll rate limit of 20 deg/s in Normal Mode.

There is no regulatory requirement on maximum roll angle. For reference, the A320 has a maximum commandable roll angle of 67 deg in Normal Law, while the A220 has a limit of 80 deg in Normal Mode. The autopilot disconnect bank angles would be much lower than these.


For completeness, Please refer to the following website:

https://www.uasc.com/docs/default-source/documents/whitepapers/uasc_rnp-rnav_whitepaper.pdf

Here are some extracts that allow to compare US and European requirements:

  US Airspace Requirements

  The current US RNP requirements are:

  RNP-10 as described in FAA order 8400.12c
  RNP-4 as described in FAA Order 8400.33
  RNAV (RNP AR) approach authorization as defined in Advisory Circular (AC) 90-101a
  Basic RNP capability is achieved through TSO-C146 compliant equipment when installed under AC 20-138().

  RNP-10 and RNP-4 procedures are limited primarily to oceanic airspace.

  RNAV (RNP AR) procedures are available in the US for domestic
  operations. These procedures require approval, hence the name:
  Authorization Required (AR), formally known as Special Aircraft &
  Aircrew Authorization Requirements (SAAAR) procedures.

  European Airspace Requirements

  There are two existing European RNP requirements:

  Basic-RNAV (B-RNAV), equivalent to RNP-5 (reference FAA AC 90-45A, AC 20-130, AC 20-138, and AC 25-15)
  Precision-RNAV (P-RNAV), equivalent to RNP-1.

  These requirements are defined in European Aviation Safety Agency
  (EASA) Temporary Guidance Leaflet (TGL)-10, and FAA AC 90-96A. A
  statement is required in the Aircraft Flight Manual (AFM) or AFM
  Supplement (AFMS).

  For European operations, a Letter of Authorization (LOA) for all RNP
  operations, is necessary, as the requirements differ from the FAA
  requirements.


What plane is this, looks a lot like a BAe-146-100 or an Avro 146-RJ100, however with only 2 engines?


How does the UK declaration for FAA pilots work?

Having gone through this process, I thought I'd share my experiences and timescales:

Useful Docs:

https://publicapps.caa.co.uk/docs/33/InformationNotice2017029.pdf
http://publicapps.caa.co.uk/docs/33/SRG2140_Issue02_Enabled.pdf

1 Oct 2018

Get a checkout from an instructor and get them to sign the SRG2140 form and also certify copies of the docs required (log book, licence, medical etc, - details on SRG2140 form)

See https://www.caa.co.uk/General-aviation/Pilot-licences/Applications/Documentation/How-to-get-copies-of-your-documents-certified/ for details on how copies are certified i.e. the wording that must be used.

Scan and submit my SRG2140 form to the CAA via email to pilotvalidation@caa.co.uk

25 Oct 2018

Phone the CAA and talk to a very helpful person who says I need to

also send in SRG2142 and use fclweb@caa.co.uk
pay £45

So I filled in that form and sent it off by email again with my CAA reference number in the subject and to fclweb@faa.com and pilotvalidation@caa.co.uk

29 Oct 2018

Got a phone call (that I missed) and an email asking for my credit card details to pay the £45
I called them back and paid the money
Later that day I got another email confirming they had sent a request to the FAA and suggesting I chase the NAA:

We are contacting you to inform you that we have processed your application for the Verification of your Third Country ICAO licence, and a verification request has been sent to the FAA.
To help ensure that the verification is received in a timely manner, you may wish to contact the NAA directly. Additional requirements may need to be met in order to release your personal details to the UK CAA.

8 Nov

I discovered that the FAA has an online portal that allows you to request a validation report so I went to https://amsrvs.registry.faa.gov/amsrvs/main.asp and asked it to send a report to me and also directly to fclweb@caa.co.uk and pilotvalidation@caa.co.uk

12 Nov

Received the validation receipt:

As the current holder of an FAA licence with a validating medical certificate, you are entitled to exercise the private privileges of the ratings for which you are qualified on your FAA certificate in UK Airspace without remuneration.
Please note that your privileges on G-registered aircraft are restricted to day VFR regardless of the medical held, as stated in ORS no.1228: ORS4. FAA Certificate holders with a valid IR flying N-registered aircraft may continue to exercise IFR privileges in UK Airspace.
Should you be ramped checked, you will have to produce a copy of your declaration made on form SRG2140 and a copy of this email.

So now I can fly G-Reg aircraft in the UK.

In hindsight, if I had to do it all again I would:

submit both forms at the same time
once they had taken the money, gone on to the FAA website and request the validation be sent directly to the two CAA emails addresses

Next step is to do a conversion to an EASA licence which involves:

(a) pass a written examination in Air Law and Human Performance;
(b) pass the PPL, BPL or SPL skill test, as relevant, in accordance with
Part-FCL;
(c) fulfil the requirements for the issue of the relevant
class or type rating, in accordance with Subpart H;
(d) hold at least a Class 2 medical certificate, issued in accordance with
Part-Medical;
(e) demonstrate that he/she has acquired language proficiency in accordance with FCL.055;
(f) have completed at least 100 hours of flight time as a pilot.

As per https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1524553458669&uri=CELEX:02011R1178-20160408

ANNEX III – Part B “CONVERSION OF LICENCES”


Do codeshare & alliances conflict with competition?

Alliances are the airline industry's way of corporate mergers. Since national airlines are still regarded as a symbol of national pride and often are part-owned by the respective governments, eradicating the proud name from the industry would be too hard to swallow. Therefore, alliances are formed in which tariffs and schedules are harmonized. The effect for you, the customer, is the effective removal of competition, resulting in monopoly pricing on routes which are served exclusively by carriers of the same alliance.

This can be compared to the car industry: Chevrolet is not competing with Pontiac or Cadillac, regardless of what the advertisements say. You might think that the wider choice of brands is a benefit, but in the end the benefits are mainly on the side of the industry.


Does the country of issue of an EASA medical certificate matter?

I discovered that it's probably better to do the medical in the UK as the country of issue of your licenses has to be the same as the country of issue of your medical. This way, I avoid the conversion.


Where do airports use 3-bar VASI for the visual glideslope?

Runway 8 at Albuquerque International Sunport Airport (KABQ) has a 3-bar VASI.

KABQ's current Chart Supplement page1 lists the VASI for Runway 8 as a VASI(V6L): a 3 bar, 6 box VASI located on the left side of the runway. The airport diagram also depicts the VASI as a V3: a three-bar VASI.

The VASI bars are also visible in aerial images, such as here on Google Maps:

1The current Chart Supplement page will expire and this link will be broken. For future reference, the updated Chart Supplement page can be found elsewhere, such as on this SkyVector page.


What is the impact of thermal Anti-Ice on descent performance?

When turning on the Anti-Ice, the demand for bleed air increases and the EEC (Electronic Engine Control) will increase the target N1 to provide enough pressure by injecting more fuel. From the Boeing 737 NG FCOMv2 (7.20.5 Engines, APU - Engine System Description, emphasis mine):

  In the normal mode, the EEC uses sensed flight conditions and bleed air demand
  to calculate N1 thrust ratings. The EEC compares commanded N1 to actual N1
  and adjusts fuel flow to achieve the commanded N1.

This impacts the descent performance as explained in the Boeing 737 NG FCTM (4.24 Climb, Cruise, Descent and Holding):

  The use of anti-ice and the increased thrust required increases the descent
  distance. Therefore, proper descent planning is necessary to arrive at the initial
  approach fix at the correct altitude, speed, and configuration. The anticipated
  anti-ice use altitude should be entered on the DESCENT FORECAST page to
  assist the FMC in computing a more accurate descent profile.

Note: the above quote is for the 737 NG models. The older 737 classic series does not increase thrust:

  Since all engines have been manufactured or modified to use a single idle speed
  in flight, the use of TAI does not increase thrust as it does in other models.


What kind of wing-surface area would Curiosity need to be able to fly in the atmosphere of Mars?

Our Flight Environment

First the basics: Mars atmosphere is mainly carbon dioxide and has an average temperature of -47°C and an average pressure of 0.004 to 0.0087 bar. The speed of sound in these conditions is 238.2 m/s, the dynamic viscosity $\nu$ is 1.14$\cdot 10^{-5}$, and for my calculations I use an atmospheric density of 0.0234 kg/m³.

Now I owe all you early upvoters an apology. The earlier answer used an unsuitable methodology; now I have improved the answer with different results.

Operating Point

Next step: The electric power supply makes a propeller the right choice, and for propeller aircraft the minimum power to sustain flight can be achieved when the lift coefficient is
$$c_L = \sqrt{3\cdot c_{D0}\cdot\pi\cdot\Lambda\cdot\epsilon}$$
This makes your zero-lift drag the real sizing parameter: Make the aircraft a little more draggy, and you get punished with a big size increase. Therefore, we strive to keep the zero-lift drag coefficient $c_{D0}$ down to 0.008 in order to keep the aircraft small.

This allows to get an idea which aspect ratio will be best: At minimum power the total drag is four times the zero-lift drag, and the lift coefficient should be as high as possible to keep the aircraft's size small. Realistically, our flight $c_l$ will not grow above 1.6 (which is the best that low-speed airfoils can manage at a reasonable L/D), so the aspect ratio is
$$\Lambda = \frac{c_l^2}{3\cdot c_{D0}\cdot\pi\cdot\epsilon}$$
which yields an aspect ratio of 35.74 when $\epsilon$ is 0.95.

Available Power

Now we can follow the procedure in this answer to calculate power demands for your solar-electric propulsion. Solar radiation on Mars is a lot lower than on Earth, but very reliable as there are no clouds to obstruct the sun. Beware of dust storms, however!

Since you gave the Martian solar constant in your question, I will use it here: The wing will be covered to 80% with solar cells, and each square meter of them will produce your optimistic 200 W (500 W radiation times 40% efficiency). Per square meter of wing we can achieve 160 W, and with an electric efficiency of 96% and a propeller efficiency of 85% this translates into a propulsive power per square meter of 130.5 W.

Matching Thrust to Drag

Now we can equate the drag $D$ and the available thrust $T$ from the power $P$, like this:
$$D = T = \frac{P}{v} => 4\cdot c_{D0}\cdot S\cdot\frac{\rho\cdot v^3}{2} = 130.5\cdot S$$
Luckily, wing area $S$ can be canceled, and we get a result for the airspeed $v$ at which the aircraft's drag can just be supported by the power the wing can generate independent of wing area:
$$v = \sqrt[3]{\frac{130.5}{4\cdot c_{D0}\cdot\rho}} = 55.857 m/s$$

Now for the real size: If we assume that the payload fraction is 25%, the mass of the full aircraft will be 4 tons. To lift this at the dynamic pressure of 36.5 N/m² which corresponds to the found flight speed we need a wing area of 254 m². This can create 40.65 kW of power, 33.17 of which are transformed into thrust. The wing span will be a whopping 95.28 m. How you get this to Mars I leave to your imagination - after all, this is just a tad less than the wingspan of the Hughes H-4.

If you can achieve a higher payload fraction, the wing will become smaller: At 30% the full aircraft mass is only 3.333 tons, and the wing size will become 211.74 m² large. Its wing span will be 87 m. With these dimensions I doubt that a higher payload fraction will be possible. The closest aircraft to this design was the Boeing Condor, which had an empty mass of 3.6 tons (with a propulsion system weighing close to the mass of Curiosity) and a wing span of 61 m.

Last Checks

Mach number: 56 m/s is just Mach 0.2345 on Mars, so we should not run into compressibility effects which would limit the assumed lift coefficient.
Reynolds number. The bigger wing has an average chord of 2.66 m and the smaller one still 2.43 m chord, and per meter the Reynolds number in -47°C cold carbon dioxide at 56 m/s is 4,900,000 - plenty enough to make the selected lift coefficient possible. Size helps here!


Is my company EASA 147 approved? How to get an EASA licence?

I am not sure what you should do, but this company is not EASA 147 certified. Source


What are interesting cases of ATC agreements between countries?

You could look into the situation regarding the airspace above northern Cyprus. This relates to 'disagreements', rather than 'agreements'!

Cyprus was invaded by Turkey in 1974, and since then the country has been split into two sections with a UN 'buffer-zone' between the two. The northern portion of Cyprus is not recognised as a separate country (well, not recognised by many States ...), and whenever 'Cyprus' is mentioned they are talking about the Greek half on the southern side of the island. Turkey still insists that the northern half is a separate country.

There are a few air-corridors that pass north-south (and v-v) over the country. A flight going from the north to south will be handled by Turkish ATC until they are at the FIR boundary mid way across the sea between Turkey and Northern Cyprus, whereupon they are told to contact 'Ercan Control'. Ercan is an illegal ATC station in the occupied part of the island which is not recognized by the International Civil Aviation Organization (ICAO). ICAO only recognises the legal government of Cyprus and has issued instructions to aircraft operators to obey only Nicosia ACC when in the Cyprus FIR.

In practise, flights generally ignore that instruction, and contact Nicosia ATC directly.

Heading in the opposite direction flights are told (by Nicosia ATC) to contact Turkish ATC, completely ignoring Ercan Control.

In practise, there are extremely few flights flying these routes, so the problem rarely arises. The use of Ercan Control is limited to Turkish flights heading from Turkey to northern Cyprus.

See Cyprus ATC


Does the flow in an afterburner have to be subsonic?

Afterburners are subsonic but not because of that equation.
Afterburners are typically subsonic for a couple of reasons. First combustion is easier at low speeds. While supersonic combustion is possible (see scramjets), most times the combustion areas of a jet are the points where some of the slowest flow through the engine occurs. Secondly, the goal of the afterburner is not to increase velocity or pressure (in fact ideal combustion is isobaric, and real combustion features a pressure loss) but to increase temperature. The reason behind this is that high temperature gas releases more energy for the same decrease in pressure than low pressure gas. This is how turbine engines are able to operate, and why combustion occurs at the highest possible pressure. After the afterburner the flow becomes supersonic traveling through the nozzle, which in an engine equipped with an afterburner is almost always variable geometry.


Is it correct to say "the up-elevator position decreases the camber of the elevator"?

You're absolutely correct, camber equals curvature. The camber of the horizontail tail is changed by deflecting the elevator, not the camber of the elevator itself. And yes the local angle of attack changes when the elevator deflects, resulting in an aerodynamic moment.


Where does ice collect first on a wing in flight and why?

"Icing conditions" is a pretty vague term that encompasses a lot of various situations that can cause airframe icing (AOPA pdf report, so it's hard to have one definitive answer. That said, you can expect to accumulate some degree of ice when flying through moisture (clouds, rain, etc) when outside air temperatures (OAT) are near or below 36°F / 2°C. Also as a rule, an aircraft's tail will likely accumulate ice faster than the wing in all conditions.

Flying through very cold temperatures (-15°C -> -40°C)

When flying in clouds and rain at the very low end of the icing spectrum, the most likely form of accumulation is rime icing. This primarily forms on the leading edges of wings and tail surfaces, starting (in most cases) with the tail, and looks (initially, at least) a lot like frost. It can create pretty bizarre structures and is pretty easy to spot. Rime ice is (as far as I have seen or read) not going to accumulate anywhere but on leading edges (wings, nose, engine nacelles, tail) as those are the only parts of the structure impacting the relative wind. Either way, it is highly detrimental to your wing's aerodynamic health.

Rime ice can sometimes form 'horns' that start to grow in a V shape forward off the wing, but only in what I imagine are considered severe conditions. The FAA states that rime "typically occurs with temperatures between -15° C. and -20 ° C".

Flying in relatively warm temperatures (2°C -> -15°C)

At warmer temps, the most likely form is clear ice, which is basically like having solid water ice form around the leading edges - again, wings, tail surfaces, nose, engines. It pretty much follows the shape of the leading edge of surface it freezes onto, but it's heavy and still messes with your aerodynamics. Again, like rime, it's freezing more or less on impact (but with larger droplets) wherever the relative wind strikes the airframe.

In some unusual conditions, aircraft can encounter precip known as Supercooled Large Droplets (SLD); these are cold enough to freeze but not on impact, causing a form of icing known as runback ice (FAA pdf). In FAA tests, "ice shape simulations were found to cause substantial penalties to the aerodynamic performance" of multiple NACA airfoils. Runback ice can accumulate pretty far back along a wing, making it difficult or impossible to dislodge using heat or boots (supposedly TKS fluid protection can mitigate this). It's scary stuff.

The FAA states that "Clear ice typically forms when temperatures are around 2° C to -10°C [but] more hazardous clear ice shapes [...] tend to form at temperatures closer to 0°C".

Flying in medium temperatures (-10°C -> -15°C)

When flying in the middle of the temperature range, aircraft wind up accumulating mixed ice, a combination of rime and clear. According to the FAA, "Mixed ice is most likely to form at temperatures between -10° C to -15° C". It is basically as terrible for aerodynamics as rime ice, and pretty much just as heavy as clear ice. No fun.

Resources:

Wikipedia
AOPA Safety Advisor
FAA Safety course on icing types
FAA Safety course on SLD


How stable is the "customer" power on a commercial aircraft?

There is a pretty great article on the design of the 777 electrical system here.

  Power for avionics needs to be clean to ensure there are no spikes or
  dips that would cause avionic failures as this could lead to otherwise
  avoidable emergency declarations.

The avionics and passenger power systems are two completely different systems. The 28V instrument power system is pulled right from the source,

  Flight instruments on the 777 are primarily powered by 28 Volts DC.
  Direct current power is supplied by three-phase transformer-rectifier
  units. There are four such units each rated at 120 Amperes.

This pulls right from the generator/alternator output of the plane. Everything ranging from your classic Cessna 152 all the way up through a 777 regulates their alternators/generators with voltage regulators and fuses to protect against current overloads. These things work in tandem to protect the avionics and internal power systems of the plane. The 28VDC system for the avionics is also connected to the battery system which prevents dips should the generators have issues outputting enough power or quit all together.

The rest of the plane is powered by 110/200V 400Hz system.

  The primary electrical system is a 3-phase, 4-wire, constant frequency
  400 Hz, 115/200 Volt system, which has been the industry standard on
  commercial jet transports since the Boeing 707

Interestingly it's 400Hz, I'm still looking to see how they get that to 60Hz.

  Since the plane is already providing clean power to the avionics, the
  power coming out of the transformers to step it down to 110V, 60Hz for
  the outlets should also be pretty clean.

The power is quite "clean" but you have some incorrect assumptions here. The power is not really stepped down. That is something that occurs on the power grid since most power lines on the street carry a significantly higher voltage than what you have in your house plugs. In this case we have the luxury of choosing an alternator/generator system that is close to (most likely slightly above) our required voltage. Slide 4 from this presentation from Boeing alludes to the fact that the system outputs 115V (and is presumably conditioned) and is then split to the cabin as well as the 28V DC bus. Power does not come out of the transformers it comes out of the generator/alternators it then is conditioned and transformed as needed. Stability is achieved though numerous conditioners and regulators, see the article I linked for more details on them.

Don't worry, it's safe to charge your laptop on a jet.


Who was the air traffic controller voice?

You are thinking of a reference to Charles ("Chuck") Yeager.  He was certainly not an air traffic controller, but there has definitely been a statement published in print saying that his manner of speaking over the radio has been the model that has been copied numerous other times (in movies and by other pilots in real life, as I recall the statement saying.)

The reference was in the book "The Right Stuff"-- pages 33-34 and possibly a few more (not shown) in this ebook edition.


What aerodynamic data (drag/lift curves) exists for the A-10?

Good luck finding number 1-3 on your list.  As far as I know these are proprietary data the you would have to get from Fairchild Republic.  After a career of flying fighters I never saw this data or really care about it.

In my opinions numbers 4 and 5 on your list are much more relevant.  What you are looking for are called EM diagrams.  EM stands for energy maneuverability and these diagrams show a scale of turn rate, turn radius, airspeed and altitude to display meanueverability at a given energy state.

Using these diagrams you can find some key performance factors:

Min maneuvering airspeed - where the rate and radius slope drops off on the left of the chard showing min flying airspeed at given altitudes and wing loading

Max instantaneous rate of turn - max possible turn rate given a certain energy state - top of the rate curve then drops off

Max sustained rate of turn - maximum rate that can be achieved while maintaining your energy state (Ps = 0)

Corner velocity - velocity to achieve max rate at a given energy state

Min radius - smallest radius of turn acheveable given a certain energy state

Radius for given conditions - important to determine this when planning something like a targeting attack

I've found an A-10 EM diagram and a good Mig-21 diagram that annotates the factors I have defined above.

Note:  I have to giggle at your "Low-Mach data is good enough for me" statement.  There is no high-Mach data in an A-10.  It will top out around .6 Mach (max speed around .7)

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Can I model propellers used in electric aircraft the same way as I model RC quadcopter drones?

The thrust T of a rotor can be given as:
 $$ T = C_T \cdot \rho \cdot A \cdot (\omega \cdot R)^2$$

With:

$\rho$ = air density [1.225kg/m$^3$] at sea level
$A$ = area of the rotor disc [m$^2$]
$\omega$ = angular speed of the rotor [rad/s]
$C_T$ = thrust coefficient.

$C_T$ depends on the configuration of the rotor: blade pitch, number of blades, blade chord etc. It can range from 0 to 0.01, without knowing more about the config of your rotor we can take the average at 0.005 the value 0.001, see update below.

The torque Q follows a similar format:

$$ Q = C_Q \cdot \rho \cdot A \cdot (\omega \cdot R)^2 \cdot R $$

For a given $C_T$, we can look up $C_q$ in the following figure, valid for a propeller solidity of 0.1. For a $C_T$ of 0.005 we find a $C_Q$ (= $C_P$!) of 0.0004, for the updated $C_T$ of 0.001 the $C_Q$ = 0.00015  Source:

Update

The above $C_T$ is valid for helicopter rotors. For quadcopters with their much smaller rotors, induced power losses, tip losses etc are much higher. This document gives a detailed discussion on $C_T$ of small rotors, although a direct comparison cannot be made since they use a different definition of $C_T$. With this in mind, and using the definition of $C_T$ as above, a better choice for $C_T$ would be 0.001, and the corresponding $C_Q$ is 0.00015.


What are the rules for logging PIC time on an IFR flight plan in mostly VFR conditions with a safety pilot?

The FAA has a legal interpretation that addresses exactly this issue, and that's what I used for this answer. We also have this question and this one that cover very similar but slightly different scenarios.

First, PIC time. Since you're instrument rated and the other pilot isn't, only you can act as PIC under IFR. So, with that in mind, when can you both log PIC time per 61.51? You didn't mention the aircraft, but I assume it's a light single that only requires one crew member.

The key point here is that operating in simulated instrument conditions is an operation that requires more than one crew member. But operating in actual instrument conditions is not such an operation.

As long as you're in VMC and assuming that your friend is under the hood, you can both log PIC time. You're acting as PIC during an operation requiring more than one crew member (61.51(e)(iii)), he's the sole manipulator of the controls (61.51(e)(i)).

But when you enter IMC, your friend continues to log PIC time as sole manipulator, however you cannot log PIC time because you're not a required crew member while operating in IMC (see the penultimate paragraph of the legal interpretation above).

Second, instrument time. The only way to log instrument time (in your scenario) is described in 61.51(g)(1) (and see this question):

  (g) Logging instrument time. (1) A person may log instrument time only
  for that flight time when the person operates the aircraft solely by
  reference to instruments under actual or simulated instrument flight
  conditions.

Assuming that only your friend controls the aircraft (manually or using the autopilot) then only he can log instrument time. If you take the controls in actual IMC then you would log instrument time but your friend wouldn't.

Third, putting it all together. Assuming that only your friend controls the aircraft throughout the entire flight and he stays under the hood while in VMC then you would log time as follows:

VMC. You: PIC (acting PIC while more than one crewmember is required). Your friend: PIC (sole manipulator), instrument (simulated IMC).
IMC. You: nothing. Your friend: PIC (sole manipulator), instrument (actual IMC)


Is is possible to use non-hydraulic fluids in a hydraulic system in an emergency?

Is it possible? Sure. Theoretically. Once.

I can't speak to your Aeroflot scenario without more details, but broadly speaking any liquid will work as "hydraulic fluid" within certain limits: At the most basic level all that is required is that it be incompressible and flow at an acceptable rate (i.e. It is a liquid with a viscosity that falls within a certain range).  Engine oil is frequently used as a hydraulic fluid for certain applications (constant-speed propellers on small aircraft), and special-purpose hydraulic oil for others (the brakes on small aircraft).

There are some challenges to using any old liquid as "hydraulic fluid" though, which are why I say this is only theoretically possible (and probably only once). The two big concerns are the fluid's operating temperature range - its freezing and boiling points - and its corrosion potential.

Let's consider MIL-PRF-5606H (a typical hydraulic oil) and ordinary lemonade as examples:

Operating Temperature Range

In terms of temperature 5606 hydraulic oil has a much wider operating range than lemonade: It's "pour point" is below -60°C and its boiling point over 175°C, while lemonade's operating temperature range is probably close to water: It will freeze somewhere close to 0°C and boil somewhere close to 100°C (the exact numbers will depend on the chemical composition of the lemonade).
If we use both of these fluids in a brake system there is a chance the lemonade will boil when the brakes are applied (creating a gas pocket that's compressible, and reducing brake effectiveness), or that it will freeze in flight and the brakes will fail to apply because the ice is blocking the lines.

Corrosion Potential

As far as corrosion potential 5606 hydraulic oil is a mineral oil with some red dye in it: Since it doesn't contain dissolved water or electrolytes it's generally non-corrosive. Lemonade on the other hand is nothing but water and dissolved electrolytes (mainly citric acid to make it taste like lemon) plus sugar and a few other things. If we ran hydraulic actuators on this stuff we should expect them to corrode (rust) and eventually fail.

So it's possible that under the right circumstances an airplane could complete a flight with lemonade, water, etc. as "hydraulic fluid", but having done so the maintenance department will have to purge the "creative" fluid from the system, and probably follow some steps to remove any corrosive residue from the system (possibly up to and including replacing major system components). Long term operation in such a condition would probably damage components to the point where many of the system's moving parts (actuators, valves, etc.) would need to be replaced.


What is "50 ft obstacle climbing speed"?

In the absence of POH guidance normally Vx is the target airspeed for a 50ft obstacle. However, when the 50ft speed is included in the POH, as it is in modern aircraft, it is based upon empirical data from flight tests.  Essentially, the test pilot flies the plane searching for the best technique to offer the best performance. When that is determined, the procedure and speeds are worked into the POH, usually in procedures and tables of speeds, but sometimes in graphs.

There is allot of engineering and test department spin on the procedures, and sometimes a pilot may get better performance using a slightly different procedure and / or speed, than published.

Also, published speeds may have a buffer in them to avoid significant performance loss, if for example a maneuver puts one close to a point where sink might be higher if the pilot's airspeed control is slightly off.

So to summarize, different manufacturers have different methods of determining what their recommended procedures and speeds are.  Sometimes there are buffers built in for speeds, and sometimes not.  Sometimes a skilled pilot can outperform the recommended POH procedure.  That doesn't happen often, because POH figures are competitive and are used to sell planes.

Side story: I was evaluating a PC-12 and C-208 as platforms for scientific instruments, and flew each one with a sales man.  The PC-12 came back with a factory test pilot to fly with me.  I wanted to fly at speeds between 61 and 64k, in the Caravan, at 500 ft AGL, and 67 to 70k in the PC-12.  The Cessna Caravan would do it comfortably all day long.  Neither the salesman nor the factory test pilot was willing to fly (or let me fly) the PC-12 at those speeds at that altitude.  I did with the PC-12 at 3500 ft AGL, and it simply didn't have the stability that the Caravan did at the lower envelope.

So the same numbers in a different plane can result in very different flight characteristics.  Vx in one aircraft could be less stable in one aircraft, but Vx+3 might be much more stable.


Which came to be first - bigger airplanes, or longer runways?

It is the larger aircraft that came first. Historically, the runway length (and design) of an airport has depended on the aircraft operating there (among other things), though this is changing. For example, the Prague airport site:

  The main runways – RWY 04/22 and RWY 13/31 – were continually lengthened during post WW II operations which kept them in line with the demands of the aviation industry until the mid 1960s...

The runway required for the aircraft depends on the take-off weight and the lesser runway length restricts the payload or range. As a result, for economical operation, the runway needs to be longer.

However, there are other constraints to consider:

For large aircraft, the runway (and taxiway) width, apron and parking space are important considerations. In most cases, lengthening the runway will be easier than taking care of these other constraints.
In the end, airports have to weigh the benefits of letting heavier aircraft operate against the resources required for runway lengthening. For major airports (like Heathrow, for example), the cost of runway expansion will run into the billions.
Unless the aircraft is going to be operated regularly (which depends on how many airports it can land), there is no point in lengthening the runway in an airport.
The economic operation of the aircraft has to be considered. For example, the A380 was designed around a 80m 'box', which the airlines had decided is the maximum size they can operate economically.
A bigger aircraft does not mean more runway required. For example, the A380 requires (slightly) lesser runway compared to 747-400.

If it comes to that, aircraft requiring more runway can takeoff from smaller ones. For example, a Boeing Dreamlifter once took off from a 6000 ft runway (it normally requires > 9000ft).

The airports with longest runways have them for different reasons- the Qamdo Bamda Airport (5500m runway) has a long runway due to its elevation (>4300m above MSL), while the Ramenskoye Airport as a long runway (5400m) due to the aircraft operated there; it was a test facility, for among other things, the Soviet Buran spacecraft.


Wind "CALM" means a wind speed less than 0.5m/s (1 kt) according to ICAO Annex 3, Appendix 3:

4.1.5.2    In local routine and special reports and in METAR and SPECI:
...
d)  when a wind speed of less than 0.5m/s (1 kt) is reported, it shall be indicated as calm;

Before Amendment 75 of ICAO Annex 3 this read:

d)  when a wind speed of less than 2 km/h (1 kt) is reported, it shall be indicated as calm;

See also Annex 3:

Appendix 5, recommendation 1.2.1
Attachment C

The FAA, in their Order JO 7110.65X (Air Traffic Control), defines a limit of 3 knots.

2−6−3.  REPORTING WEATHER CONDITIONS
....
b. Describe  the  wind  as  calm  when  the  wind velocity is less than three knots.


What mode is the Boeing 777's autothrottle in right after touch down?

During the flare somewhere between 25' and 50', the A/T retards the thrust levers to idle. They remain in idle mode until reverse thrust is selected which automatically disconnects the A/T.

In the case of Emirates 521, eyewitnesses observed the aircraft do a bounced landing and then attempt a go-around reaching a max altitude of about 150'.

Because the aircraft had touched down, it can be assumed the A/T had automatically gone to idle, and it appears the thrust levers were not manually advanced. The aircraft then settled back on the runway as the gear was being retracted.

More speculation here:  Emirates B777 crash was accident waiting to happen

  a pilot colleague observed exactly what happened as he was there, waiting in his aircraft to cross runway 12L. The B777 bounced and
  began a go-around. The aircraft reached about 150 feet (45 metres)
  with its landing gear retracting, then began to sink to the runway.

  This suggests that the pilots had initiated a go-around as they had
  been trained to do and had practised hundreds of times in simulators,
  but the engines failed to respond in time to the pilot-commanded
  thrust. Why?

  Bounces are not uncommon. They happen to all pilots occasionally. What
  was different with the Emirates B777 bounce was that the pilot elected
  to go around. This should not have been a problem as pilots are
  trained to apply power, pitch up (raise the nose) and climb away.
  However pilots are not really trained for go-arounds after a bounce;
  we practise go-arounds from a low approach attitude.

  Modern jets have autothrottles as part of the autoflight system. They
  have small TOGA (take off/go-around) switches on the throttle levers
  they click to command autothrottles to control the engines, to deliver
  the required thrust. Pilots do not physically push up the levers by
  themselves but trust the autothrottles to do that, although it is
  common to rest your hand on the top of the levers. So, on a go-around,
  all the pilot does is click the TOGA switches, pull back on the
  control column to raise the nose and — when the other pilot, after
  observing positive climb, announces it — calls “gear up” and away we
  go!

  But in the Dubai case, because the wheels had touched the runway, the
  landing gear sensors told the autoflight system computers that the
  aircraft was landed. So when the pilot clicked TOGA, the computers —
  without him initially realising it — inhibited TOGA as part of their
  design protocols and refused to spool up the engines as the pilot
  commanded.


What is this airplane that sits in front of Barringer High School in Newark, NJ?

It's a Fourney Aircoupe  that's seen better days. Much better days...


Is there a rule-of-thumb for estimating distance to an aeroplane?

A rule-of-thumb would imply frequent usage. Such as this list on SKYbrary.aero: Rules of Thumb.

For usage by pilots and/or controllers, a distance-to won't be beneficial even if there was a rule-of-thumb (there isn't).

Imagine two planes on approach to a runway, the controller uses his thumb, now the following plane is also higher, so we have different slant angles: it just won't work to judge their separation (and on a foggy day it's of no use of course).
Imagine a pilot flying VFR, at night. The pilot spots the navigation lights of a plane, but nothing else to judge the plane's size: again won't work.


What is the physics of crosswind landings for large airplanes?

When the wind acts on the tall fin upon touchdown, is there a yaw effect, or does the wind push the airplane downwind? And what is the rudder correction to be anticipated?

Let's assume a strong crosswind at 90° from the right with a 747 on a dry, uncontaminated runway for illustration purposes.

Once the airplane is firmly on the runway, the wind is acting on the whole airplane, with the crosswind pushing it downwind, and given the greater side force aft of the c.g. (especially because of the tailplane) than the side force forward of the c.g., there is at the same time a net yaw effect wanting to rotate the airplane about the c.g. into the wind.

Perhaps its best to think of the rudder pedal displacement not just as where you want the rudder, but also what you want the nose gear to do. While there were some 747s that had no connection between the nose gear steering and the rudder pedals, most did (at least the ones I flew). Now think of what you have to do to get the airplane where you want it, pointed in the direction you want, and actually traveling in the direction you want.

What you want to wind up with is the airplane's longitudinal axis on the runway center line, nose pointed straight down the center line, and the airplane actually moving straight down the center line. Let's say you've succeeded in getting the airplane to that state. To keep it, in our strong 90° right crosswind,you would use right aileron to keep the wind from getting under the upwind wing so to speak, and some left rudder. How much would depend on whether you had rudder pedals that connected to the nose gear steering, your speed, your weight and when you started using the tiller for steering. I forget the details of the connection between the nose gear steering and the rudder pedals, but it's not linear, and as I remember you can have the nose gear tracking straight ahead even though you are using some rudder.

On a 747, once you've slowed down to tiller speed, you would use it, and on a dry, uncontaminated runway, the main and wing gear will keep you from moving sideways and the nosegear will control your direction of movement, at least in the strongest of winds I operated in, say 40-45 knots or so.

Chances are, once you are firmly on the runway after touchdown, you will not be exactly on the center line nor pointed precisely down the runway. Your first and second illustrations are dealing with getting there from a less than ideal touchdown, and if I understand them, they are correct. If to the right of the center line, you can allow a drift leftward. If to the left, you don't have a lot of room to spare so you need positive action to get to the center line.


Why five touchdown zone markings for only one aiming point?

ICAO Annex 14 specifies the need for 6 pairs of touchdown zone markings for runways with a landing distance available of 2400 metres or more.

As noted in Annex 14, the number of markings relates to the landing distance available.

Presumably, the rule is there to make it easy for a pilot approaching the runway to make sure the runway is long enough if, for some reason, they are uncertain of the runway length. Similar logic could probably be applied to the rule regarding threshold markings ("piano keys"): What does the number of white bars in runway's threshold mean?


Are there little seat belts or other restraints for the organ-containing coolers kept in cockpits?

"between the pilots" depends on the aircraft. On larger commercial aircraft and even some fairly small planes the area between the seats is occupied by the FMS and throttle units and there really isn't anywhere to put a cooler as seen here:

(source)

A lot of aircraft (bigger than the PC-12 mentioned) have jump seats in the cockpit. If unoccupied these seats have a set of restraints that could theoretically hold a cooler depending on size.

You can find the legality of putting stuff on the floor in the cockpit in answer to this question.

For short distances organs move in helicopters and for longer distances they may move in a private jet presumable in the back with a courier. I would not jump to the conclusion that coolers in the cockpit are organs. Ive seen a few organs loaded into lear 35's at my local airfield.

For the record, if you ever see a cooler in my cockpit its more than likely a ham and cheese sandwich.


What distinguishes the Airbus-Sidestick from an ordinary gaming joystick?

First of all, I'd like to make clear that I highly respect Airbus cockpit design and implementation of envelope protection.

Now to the question. The Airbus side stick is a lot stronger than a game joystick and very reliable, but is functionality-wise the same as a gaming joystick, just a stick loaded by a passive spring force sending back position signals. It had to be that way in the 90s when the sticks were designed, although we were already running digital force loops in real time @ 5000 Hz on a Motorola 68020, and had the technology to couple two sticks in software. Did it for Mercedes and for quite a few simulators, but sadly not for Airbus.

So how it could for instance be implemented for the A320 side stick: program the passive forces that are there now for normal operation but always couple the sticks, program a stick pusher for when in alternate law and stalling, and leave the current override button solution in for when the Control Loading System fails. We were part of an aircraft company then and making the system airworthy would not have been a problem.


Could a quadcopter fly if its propellers were encased in cylindrical tubes?

Yes. It would be able to turn. Of your 4 propellers, 2 spin clockwise and 2 spin counterclockwise.  The torques cancel out.  To make it spin, you run the 2 clockwise propellers a little faster and the other 2 a little slower.  Now the torques do not cancel out and the quadcopter spins.  This does not change if you have a ducted fan versus a propeller


These guys could probably answer this question.

It'll cost you $20, but you can obtain a MiG-23 POH here which should have a systems description in it for the jet's fuel system.

http://www.flight-manuals-on-cd.com/MIG23.html


How does the Eurocopter Blue Edge and Blue Pulse rotor blade design work?

EC155 helicopter. Compared with a conventional blade, the Blue Edge has a tip with both forward and rearward sweep.
This gives the blade more time to interact with the vortex 'shed' by the rotor, reducing the characteristic impulsive (slap-slap) blade-vortex interaction noise generated by a helicopter.
The active trailing edge flap harmonises the frequency thus making it quieter.


Which countries permit pilots to carry a firearm?

I spent a bit of time Googling this and I couldn't find any other country that systematically arms pilots using a public, open program like the FFDO. What countries might do in secret is anyone's guess, though.

The most obvious candidate is Israel, since El Al is famous for its tough and often very visible security. There are many reports that El Al uses sky marshals (one article says "on all flights"), but I couldn't find any mention of the pilots themselves being armed. That doesn't mean they aren't armed, but it at least suggests that there is no public program in Israel comparable to the FFDO.

For the same reason, the lack of information about similar publicly recognized programs in other countries strongly suggests that they don't exist.


Will high blood pressure affect my pilot medical certification?

Without knowing German, it's a little difficult for me to research the LBV's website, but I found this application for Validation of a foreign airman’s licence, and one of the requirements in it is:

  Valid JAR-FCL Medical Class I or Class II

The JAR requirements for a Class I and Class II medical, both are:

  JAR–FCL 3.135 Cardiovascular system – Blood pressure

  (a) The blood pressure shall be recorded with  the technique given in
  paragraph 3 Appendix 1 to  Subpart B [at each examination].

  (b) When the blood pressure at examination  consistently exceeds 160
  mmHg systolic and/or  95 mmHg diastolic, with or without treatment,
  the  applicant shall be assessed as unfit.

  (c) Treatment for the control of blood  pressure shall be compatible
  with the safe exercise  of the privileges of the applicable licence(s)
  and be  compliant with paragraph 4 Appendix 1 to Subpart

  B. The initiation of [ ][medication] shall require a  period of
  temporary suspension of the medical  certificate to establish the
  absence of significant  side effects.

  (d) Applicants with symptomatic hypotension  shall be assessed as
  unfit.

It looks like you will probably need to lower your blood pressure (either via diet and exercise or with medication) in order to pass your medical.  If you start taking blood pressure medication, you will need to take it for a certain period of time to make sure that there are no other side effects before they will give you a medical.  You can discuss this with a medical examiner to see how the process works there.


Brace position - Why hands atop head in the UK, but on ankles or atop seat in front in the US?

The difference is just because there are often disputed methods on which technique is best. To be brutally honest, many accidents are so severe and can't really be analysed, so this is still a point of contention.

I would hypothesize that the UK version is safer as the hand position protects the skull and face from direct impact with the seat in front; instead colliding with the inside forearm. This will naturally reduce impulse (strengthy plastic vs. fleshy skin) and should thus reduce injuries.

The concept of holding ankles stems from the position your body is put in when holding your ankles. Any kind of "holding" is fine, touching on top or sides. It puts your body into a position that ducks your head and should (because of close seat proximity) rest your head against the seat infront anyway.


Why don't modern aircraft have landing gear that can swivel to compensate for crosswinds?

There is one aircraft I know of that can do exactly what you state, the B-52:

This plane has steerable dual-bicycle gear which allows the crew to point the gear along the runway while the fuselage is "crabbed" up to 20* off the runway centerline. AFAIK the gear are slaved to the ILS; you dial in the OBI to a course and the gear will point that way even if the aircraft points differently.

The reason this was done is primarily due to the design of the rest of the aircraft. It's a very "dense" design, cramming a lot of weight into a very small package, requiring massive wings and tail just to keep the thing under control at altitude. These surfaces then become huge sails at lower altitudes, and with the high, anhedraled wing arrangement on a relatively low fueselage, there's not much room for error. B-52 pilots often say you have to fly 2 seconds ahead of the plane, it's that slow to react to pilot input. So, classic "de-crabbing" techniques involving a hard rudder with counter-aileron just aren't going to work with a BUFF. You have to land crabbed and correct after touchdown, and on a dry runway that isn't a good idea either with an aircraft of this size.

Modern airliners, for their size, are much easier to maneuver on the whole than the BUFF. Really big ones, like the 747, actually have steerable main gear as well, but AFAIK the 747's mains can only be actively steered on the ground, and because they counter-steer to the nose gear (helps bring the tail around corners; imagine driving something about 4 times longer than an 18-wheeler) they would actually be pointed further off the runway line when de-crabbing.

Four- and six-wheel main gear systems used on larger airliners (777, 787, A380) actually have a small amount of castering built in; if you watch YouTubes of crosswind landings (there are several) you'll see that the rear two wheels of each gear touch first and actually twist the entire "truck" into line with the aircraft's actual direction of travel. Then as the plane settles on the gear and the fuselage lines back up with the runway, they'll straighten. Planes with one- and two-wheel main gear don't need this as much (and such a system isn't as effective as the first point of contact of a tire is directly level with the gear strut instead of behind it).


Why aren't airliner windows aligned with their seats?

Because the pitch of the frames is not related to the pitch of the seats. The windows placement have to cut through as few frames as possible.

You can see it in the following picture, noting that frames are "highlighted" by the vertical riveting

Image source

It is even more evident in the picture contained in this answer on UX.SE:

Because the aircraft is designed once, but "decorated" by several airlines in several different manners. For example, an A320 or a B757 will have the windows always in the same locations, but depending on the airline that is using it, it will most probably have the seats in slightly different locations.


Why do we call moving an aircraft on the ground "taxi"?

This online etymological site suggests that an airplane moves slowly across the field in a similar fashion to how a taxi-cab driver would slowly make his way down a block looking for fares, and the term is borrowed from that behavior.


How is a Class E airport distinguished from a Class G airport, based on the identifier?

Airport identifiers do not distinguish the airspace that surrounds them. As for why airports start with a K you can look at the answer here. To figure out the airspace that an airport sits in you must look at the airspace designation lines around it (see page 10 here).


Is the lift produced by a wing with a 10° flap equal to the lift created by a wing with 10° AOA but with no flap?

No, there is a big difference between an entire wing being at an angle of attack and a small part of the wing being at an angle of attack.


What is the record for the highest achieved landing speed?

If that's the case, Hauptmann Hetzel was one uped by an Israeli F-15 pilot named Zivi Nedivi, who landed his jet with only one wing after a MAC with an A-4.  The touchdown speed was estimated to be at 260 kts (300 mph, 480 km/h).  That's the fastest landing I'm aware of where the pilot lived to tell the tale.

https://theaviationist.com/2014/09/15/f-15-lands-with-one-wing/

Now the highest known approach speed during normal operations, I believe, goes to the North American X-15 research aircraft/spacecraft, which crosses the fence at some 211 KIAS (242 mph, 388 km/h).

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-052-DFRC.html

Also known to have very high approach speeds were the M2-F2, M2-F3, HL-10, and X-24A lifting body research aircraft with Vrefs in the 190-200 KIAS range.


What are the differences between an OBS, a CDI, a Heading indicator, and an HSI?

Check out this manual from the FAA on flight instruments

Heading Indicator:

The heading indicator is fundamentally a mechanical
instrument designed to facilitate the use of the magnetic
compass. Errors in the magnetic compass are numerous,
making straight flight and precision turns to headings difficult
to accomplish, particularly in turbulent air. A heading
indicator, however, is not affected by the forces that make
the magnetic compass difficult to interpret.

Heading Indicators are not VOR related. They simple provide an alternative to the compass and are generally used when the compass reading may be inaccurate (non straight and level flight). Due to their functionality they need to be periodically aligned with the compass.

Course Deviation Indicator:

A course deviation indicator (CDI) is an avionics instrument used in aircraft navigation to determine an aircraft's lateral position in relation to a course. If the location of the aircraft is to the left of course, the needle deflects to the right, and vice versa.

The OBS (Omni Bearing Selector) knob is on the CDI, it is not its own instrument. The knob allows the selection (via the outer ring) of the radial (course) you wish to track from a VOR ground station. When tracking a radial you only track left/right deviation and thus only a single needle is required (the first picture you have). For instrument flying you also need to track the glide slope for an approach and thus vertical deviation may also be displayed on a CDI. When on an instrument approach the CDI is used to track the left/right deviation from the runway (not a VOR).

Horizontal Situation Indicator (HSI):
Is a CDI and Heading Indicator packed into one unit. it provides both left right deviation along with glide slope information as well as heading indication in turns. Many HSI's are coupled to auto pilots and may allow course selection via a heading knob if they are connected to do so. The HSI is not any more advanced than the sum of its counter parts but it is more complex and to a new pilot may be hard to read.


Can airlines schedule more flight arrivals than the destination airport capacity?

I'll answer for the US. As long as there's no official slot program, airlines can schedule however much they want to an airport, beyond what it should be capable of handling.

Now that doesn't mean ATC lets a free-for all happen. Hopefully, various traffic management units are on it and aware of how much demand is scheduled and already airborne into the airport/region/area that there's too much demand, and will implement various flow control programs to moderate the volume to what can be accepted into a specific sector(Certain airways can get super busy and require these types of actions), or airport. These control programs will either slow aircraft farther out from their destination, hold, or give small to longer delays on the ground, depending on how over scheduled or limitations of weather at the destination.

[Begin edit poriton]
Since the other part of the question wasn't there when I first answered, I'll answer now.
Slot controls vary heavily from airport to airport. In the US, LGA, LGB, DCA, SNA, and at times JFK are slot controlled, with a few others threatened to go to slots due to how many delays they impact the system(SFO, EWR, and ORD). How each airport deals with the slot allocation is different due to how they got slot controls. DCA is controlled partly through congress, LGA and SNA are restricted due to noise controls. In the US, once an airline gets a slot, often times it's considered transferable property, so airlines can sell them to each other if needed.

Now if a slot isn't used and goes back to the airport, the airport can put it up for bid, or allow applications for it, again depending on how their program is structured. AT DCA, some slots are transferable, some require an act of congress to change or modify, and some can only be used for certain routes or types of cities.


What is the difference between Best Rate of Climb and Maximum Rate of Climb?

Generally when GA pilots talk about climb performance we speak of two different airspeed values:

Best Rate of Climb speed (Vy) gets you the most altitude per unit time (feet per minute).
When you want to get to cruise altitude quickly for maximum efficiency you'll aim for the best rate of climb so you spend the least time at lower, less efficient altitudes.

Best Angle of Climb speed (Vx) gets you the greatest altitude per unit of ground distance (feet per mile).
When you've got a FAA-Standard 50-foot-tree at the departure end of the runway you'll aim for the best angle of climb to ensure you don't wind up in the tree.

Those speeds are useful to us as pilots, but the exact rate of climb (feet-per-minute) for those speeds will vary: A fully loaded plane will climb more slowly than one that's just got the pilot and a few gallons of fuel on board, and that's where the "maximum rate of climb" enters into the discussion:

Maximum rate of climb is the number of feet per minute you can get climbing at the "best rate of climb" airspeed.

If someone is being sloppy in their usage "Maximum Rate of Climb" could mean "Best Rate of Climb" (pitch for Vy and you get what you get), but if you're being precise in your usage and really talking about the rate of climb it would mean the theoretical maximum rate of climb in feet per minute based on the current conditions and aircraft weight.

Maximum rate of climb under a given set of conditions is useful information to know if you need to clear terrain at some point on your flight path and want to be sure you can climb fast enough to do so: If you're starting from sea level and need to clear a 5000 foot mountain that's 5 minutes away but your plane can't manage more than 500 feet per minute at best-rate-of-climb speed under the current conditions you'll need to reconsider your flight plan to either avoid the mountain or climb in a circle somewhere until you can clear it.


Which agency issues private pilot certificates?

Here in the USA the FAA is the agency that issues all levels of Pilots Certificates. However the certificate is not simply applied for, it requires training and the passage of a written, oral, and practical exam. You can find the current requirements here.

For reference the NTSB investigates accidents (all transportation accidents for that matter)

And ICAO is a UN organization that deals with coordinating aviation related maters all over the globe.


Rolling take off compared to take off from a standstill

There are a few things that may be going on.

Generally the foot on the breaks, full throttle, spool up, release and roll is derivative of a short field takeoff. In other words you need all available runway and all available power to get off the ground safely and clear your runway end obstacles. This is dictated by airplane performance and runway conditions/length.

Roll on, roll into full throttle and go is more or less standard. In some cases this may follow an ATC clearance like

  123AB Cleared for takeoff 22 depart no delay

This generally means there is either someone inbound for a landing but theres time for you to go, or there is a long queue on the ground and the controller wants you to get going. Stopping on the runway to spool up your engines takes time and at a busy field that can be in short supply.

Its important to note that in any case the pilot should line the aircraft up with centerline prior to applying full throttle.

The aircraft can also be instructed to, "line up and wait" in which case its cleared to enter the runway and wait on the numbers until cleared. This may occur at an airport that offers parallel runway operations and the aircraft is waiting for a plane to land on a parallel runway.

EDIT: I found a possible dupe, noted in the comments. Its a bit different so ill leave this answer here and let the community decide.


Can I be a pilot now considering the new advancements in color vision lenses and glasses?

According to FAA guide for Aviation Medical Examiners:

F. Color Vision Correcting Lens (e.g. X-Chrom)
Such lenses are unacceptable to the FAA as a means for correcting a pilot's color vision deficiencies.

However, you have the option of taking other tests for color vision. It would be better to talk with your physician or the medical examiner about this.


What surface materials do airplanes use to reduce friction?

In a way, yes. By using smooth metal surfaces with countersunk rivets, modern aircraft use a surface with low friction already. In the past, wooden structures were varnished to give them a smoother surface. In the second World War, German crews would polish the normally matte paint of some of their airplanes to eke out the maximum in top speed.
There have been several attempts in the past to improve the smooth metal surface. The most attention was heaped on riblet surfaces, a grooved plastic foil the surface of which was inspired by shark skin. Since the 1980s several experiments were made with partially riblet-covered airplanes, boats or wind turbine blades. The gains of up to 8% in drag reduction are real, but the application and maintenance of riblet-foil covered surfaces made the technique impractical.

Shark skin surfaces (picture source). The common understanding is that the streamwise grooves will suppress oscillations in the flow and reduce friction drag. The overall effort to maintain this surface has so far been considered too high in order to achieve the small reduction in drag that is possible with a grooved surface.
And now for something completely different …
Monocrystalline solar panels would result in a polygonic surface and need to be embedded in clear resin to produce the desired curved outer surface. Solar foils are much easier to apply and weigh much less, but also have a lower efficiency. So far, only experimental airplanes have used solar panels on their skin and the integration of those panels was a major part in the overall cost of those airplanes.

The Gossamer Penguin used a rather clumsy way to add solar panels in order to avoid the major work of integrating them into the surface (picture source). It should be obvious that this way of integration adds both drag and weight.

Solar panels of the Solar Impulse II (picture source). It used a rectangular wing planform to make the integration of the solar panels easier since the same mold could be used for all wing panels. Now the solar panels do not add viscous drag, but the weight of the panels, their wiring and the clear resin needed for the smooth, curved surface adds weight which causes an increase in induced drag.


What does it mean to have a SIC limitation on your medical class 1

This EASA document Easy Access Rules for Medical Requirements explains what the Specific Medical Examination (SIC - Medical Certificate Limitation Code) is and how it applies to medical qualifications for pilots/crewmembers). An explanation of what it means is found in the EASA document referenced above on page 52, item 8:
(8) SIC   Specific regular medical examination(s)   contact the medical assessor of the licensing authority.
This limitation requires the AeMC, or AME to contact the medical assessor of the licensing authority  before  embarking  upon  a  revalidation  or  renewal  aero-medical  assessment. The  limitation  is  likely  to  concern  a  medical  history  or  additional  examination(s)  which the AeMC or AME should be aware of prior to undertaking the assessment.
Apparently it means that when you go to revalidate or renew your medical certificate the AME will have to contact the medical assessor of the licensing authority and you will have undergo some additional testing or the AME will be made aware of some specific medical history or issue that needs to be considered prior to renewal or recertification of your medical certificate. Perhaps similar to having a non-obstructing kidney stone reevaluated or a blood sugar evaluation. This would depend on the medical reason the SIC notation (limitation) was placed on your medical certificate.
The EASA linked document (above) provides additional information relating to the SIC Limitation Code on a Medical Certificate.


How are the glide polar and L/D ratio charts related?

Let's look at what exactly is shown by each curve:

The glide ratio curve plots glide ratio (horizontal distance divided by vertical distance) against airspeed.
The polar curve plots vertical speed against airspeed.

The x axis (airspeed) is the same for both plots, but the y axis is different. To convert one curve to the other, we need to convert glide ratio to vertical speed and vice versa.

  Note: I'm going to make a slight simplification here and assume that airspeed is the same as horizontal speed. This is not true when climbing or descending. A more accurate answer will require some trigonometry to calculate horizontal speed from airspeed. But the error introduced by this simplification is very small.

Vertical speed is simply airspeed times glide ratio.
Glide ratio is simply vertical speed divided by airspeed.

So, to make one curve out of the other:

To plot the polar curve, take a glide ratio curve and multiply it by the x coordinate (thus converting glide ratios to vertical speeds). Conceptually, as you travel outward on the x axis, you are magnifying the curve by x.
To plot a glide ratio curve, take the polar curve and divide it by the x coordinate (thus converting vertical speeds to glide ratios).

You mentioned parabolas. The polar curve is a "parabola" only in the vaguest sense that it is shaped like a parabola. It is not a precise mathematical parabola. Its exact shape is determined by extremely complicated aerodynamic factors.

All this being said, if your airplane has a published polar curve, use it, instead of deriving your own. Its values were measured and verified during flight test and you're better off using those than something you produced yourself using other data.