I will answer this for the regulations and general procedures in the USA as laid out by the FAA, operations may vary elsewhere in the world. AOPA publishes a nice guide on how traffic flow at un-towered/un-controlled fields works and I would advise giving it a read as it covers a wide variety of scenarios. Effectively planes self announce and monitor radio traffic as they approach and depart the airfield.

Basic right of way is established in FAA FAR 91.113 and provide guidelines for operations. While some more specifics can be found in FAA FAR 91.126 and FAA FAR 91.127 relating to un-towered/un-controlled operations specifically.

Ill provide a brief example of a departure and approach (as would be heard on the radio over the Common Traffic Advisory frequency "CTAF"). You as the pilot in command are always responsible to "See and Avoid" so you should always have your heads up on approach to a field looking for traffic.

  Plane is started and taxied to the run up area, checked, and lined up at the hold short line with out making any calls. You simply look around while taxing as you would when driving a car. The only exception to this is taxing on the actual runway which requires a "Piper Archer Back Taxing 05" call.
  (check downwind, base, and final for incoming aircraft as you monitor the radio for calls)
  (when you see its all clear) "Piper Archer taking 05 for a Northbound departure"
  Enter the runway, make sure its clear, takeoff
  Follow any procedures that the airport may have (noise abatement etc.)
  "Piper Archer departing the pattern to the north"

Then for a basic arrival you should fly the standard traffic pattern as outlined in the AF/D for the given field.

  Tune radio to CTAF and listen in if no one else is making announcements you can begin yours. For the most part everyone will make the following announcements or a similar variant there of.

  "Piper archer 5 miles to the north, inbound for a landing on 05"

  "Piper archer entering left downwind for 05" (General procedure calls for entering the traffic pattern on the downwind leg)

  "Piper Archer turning base for 05"

  "Piper archer turning final for 05"

  Land

  "Piper archer clear runway 05"

Some points to note. If you hear calls of others in the pattern you can still enter. Generally you want to be 1 or 2 legs behind the plane in front of you. This varies depending on what you are flying and what they are flying. For example I was landing one day in my Archer and a Seneca was inbound behind me but close, him being the heavier and far faster aircraft I let him in. Over the radio I allowed him to overtake me (I extended my downwind for him) since he was the faster plane I did not mind having some extra time to set up my approach.

On short final you should always be checking to make sure that no one pulls out onto the runway or that no one is departing. At an un-towered field dont be afraid to go around!

As Ron mentions in the comments below, there is, strictly speaking, no regulation requiring you to have a radio on board for VFR flight. That being said some older planes that lack full electrical systems also subsequently lack radios. Many have hand held units on board but again are not required to. In this case they must observe the traffic flow and enter the pattern in a safe manner, this is why you should always have your heads up looking out for aircraft doing this.

  wouldn't there be factors like weather which can cause accidents?

At both big and small airports weather is handled similarly. If the conditions are VFR then a visual approach is conducted and you can avoid other aircraft by simply seeing them. The scenario above is a standard VFR arrival and approach. If the weather calls for an IFR approach and and you are in an IFR equipped aircraft and furthermore the field has an IFR approach into it (be it RNAV or GPS etc.) you may conduct an IFR approach into the field. In this case you will make calls at the proper call out points on the approach (similar to a VFR call out). Since you cant physically see the other traffic in this case radio monitoring is key.


What is the air/fuel mixture ratio in a turbojet engine?

This cannot be answered specifically, the stoichiometric fuel/air ratio (FAR) is based on burning all oxygen, while for cooling purposes the airflow is generally much higher; therefore the FAR will be lower than the stoichiometric FAR. Note that you do not want to burn fuel at stoichiometric conditions as this produces the most nitrogen oxides. Fuel is being burnt rich and then quickly burnt lean.

Note that the FAR is depending on the speed, altitude and power setting (and the type of engine). To quantify the FAR, you would need to model the engine and simulate the performance. As an example (very simple to show the effect) a turbine exit temperature sweep for different altitudes and Mach numbers is shown below for a simple turbojet engine (the engine linked in the comments of the question is practically a turbojet engine considering the very low bypass ratio). You see that the FAR is variable (top graph is the burner exit FAR, bottom is the stoichiometric FAR):

I cannot address the second part of the question regarding the accident rate, that does not seem to be relevant.


What type of aircraft would fly with an orange light at night?

While normally red in colour, anti collision lights can often appear more or less orange, depending on the background and atmospheric conditions. It is impossible to determine the aircraft type just based on the fact that it has a orange light on it, since almost all aircraft have reddish orange anti collision lights.


MH370 Curved Track / Arc to southwest...Isn't this also affected by the Earth's motion?

Not significantly. The aircraft flies in the air. The air moves over the earth and takes the plane with it. Of course wind is affected by the rotation of the earth, but there is little direct effect of Earth's rotation on the motion of the plane. The coriolis forces have a negligible effect on the aircraft's track.

The Inmarsat satellite used is geostationary, so it rotates as fast around the earth as the earth around its axis. The nett effect is zero.


If I own land, can I create a private runway on my property for my own use?

In short: Yes, you can. The FAA doesn't really care, as long as you're not going to interrupt class B or C operations. And honestly as long as you're not hosting a dozen other aircraft, how are they going to tell the difference between a field and an airstrip? If you want it on a chart or you are near special airspace, you need to contact the FSDO and talk to them about it (it's good to do that anyway). They will send someone out to survey it and talk with you, and hopefully approve it.

It's the local authorities that usually ends up being troublesome. Your state/county/city might have laws that apply, and you'll need to find that out on your own. A friend of mine spent just a few days talking/meeting with the FAA on his strip, but spent weeks dealing with the state transportation department and a local ban on new grass strips which he sat right on the border of (as in it was a ban in a 50 mile radius and his house was on mile 50).

Persistence is key, good luck!


What is the typical blade pitch angle of a ram air turbine?

Ram Air Turbines have variable pitch which is set according to demanded load and airspeed, and the controller keeps the rotational speed as high as possible for maximum efficiency. Typical operational RPM of a RAT is between 5500 and 7700 rpm, at speeds between 125 - 375 knots. Let's take the averages: 6600 RPM @ 250 knots = 700 rad/s @ 130 m/s.

At a disk diameter of 1 m and a spinner diameter of 20 cm, lets look at velocity triangles at the blade root, centre and tip:

Blade root: R = 0.1 m, rotational speed $V_{rot}$ = 0.1 * 700 = 70 m/s. With incoming air at 130 m/s, this creates a local velocity pitch angle of arctan (130/70) = 62 deg
Blade centre: R = 0.3, $V_{rot}$ = 0.3 * 700 = 210 m/s, velocity pitch angle = arctan (130/210) = 32 deg.
Blade tip: R = 0.5, $V_{rot}$ = 0.5 * 700 = 350 m/s, velocity pitch angle = arctan (130/350) = 20 deg.

Note that these are unloaded velocity triangles, the blades can only generate power with air coming in at a local angle of attack. We're rough estimating, so you could take a pitch of 25 deg at tip, 35 at centre, and linearly twist onto 45 deg at root (most of the power is generated at the outer part of the blade).


Have there ever been accidents due to a vacuum failure that hasn't been noticed?

There have been many accidents because the vacuum system failed; AOPA has a good article that discusses some of them, and see this NTSB preliminary report for an example.

As for accidents caused because the pilot didn't notice, that's a more difficult question: if the pilot didn't survive then there's no definitive way to know what happened and what he experienced. It's always possible that the pilot was fully aware that the vacuum system failed, he just wasn't good enough at partial panel flying to keep the aircraft under control.


What material is used to make the hot sections of jet engines?

Short answer

Fan: Aluminum, titanium, or stainless steel
Compressor: Nickel-, cobalt-, or iron-based alloys. Additive are aluminum and/or titanium, chromium, as well as rare earth elements like yttrium.
Combustion chamber: Superalloys with refractory metals such as tungsten, molybdenum, niobium, tantalum. Ceramics and ceramic-metal mixes.
Turbine: Nickel-based superalloy, outside air is circulated through channels inside of the turbine blades. For lower pressure turbine blades iron-based superalloy or even stainless steel. The metals used for turbine blades are often grown as a single crystal.
Exhaust nozzle: Nickel Inconel and stainless steel alloys.
Casing: Aluminum or polymer matrix materials.

The high-pressure turbine is, with the combustion chamber, very hot (more than the exhaust nozzle). You may read this Wikipedia article which has a short list of materials used for turbine blades (with alloys names and cooling techniques).

Engine structure (turbofan)

(source: Wikipedia)

An actual engine looks like that (CFM56 turbofan). It's easy to map the detailed elements to the simplified schematic. The fan pushes about one ton of cold air in the engine every second in high power turbofans. This is why temperatures and pressures can be so large after compression and after combustion.

All quotes are from Nasa Guide To Engines, 2007.

  In 1903, the Wright brothers built an aluminum
  block engine because of its light weight compared to cast iron. Its
  melting point of 660 °C was well above the engine’s operating
  temperature, so for them it was a good choice. However, aluminum could
  not be used in the hotter parts of a turbine engine where temperatures
  reach of 1800 °C or more because it would melt.

Fan

  This typically does
  not get very hot (<150 °C) so aluminum, titanium, or stainless steel
  are all suitable for the fan blades. Most engines use titanium because
  it has a high strength-to-weight ratio, is corrosion and fatigue
  resistant, and would be able to withstand the impact of a bird strike.

Fan example (with a fan blade missing after the engine blew apart).

Compressor section

  The pressure of the air can be raised up to 30 times and the
  temperature, depending on the number of stages in the compressor, can
  rise to 1000 °C. Here the materials must have high strength at high
  temperatures; must resist fatigue, cracking, and oxidation; and also
  must resist “creep.” Creep is the tendency of a material to slowly
  change shape when stressed at high temperature. Since no single metal
  would have all the desired properties, an alloy (a mixture of metals)
  is used. Very high- temperature alloys are called superalloys and are
  generally nickel-, cobalt-, or iron-based alloys. Aluminum and/or
  titanium are added for strength, and chromium, as well as rare earth
  elements like yttrium, are added to improve corrosion resistance.

Compressor example (high pressure rotors)

Combustion chamber

  Temperatures can exceed 1800 °C and again superalloys are used, but
  without the titanium or aluminum for strength because there are no
  moving parts. Instead, refractory metals are often added to a
  superalloy. These are metals of unusually high resistance to heat,
  corrosion, and wear such as tungsten, molybdenum, niobium, tantalum,
  and rhenium. They are used in alloys and not as pure metals because
  they are among the densest of all the elements, a negative property
  when it comes to aircraft that need to keep weight to a minimum.
  Ceramics and ceramic-metal mixes are also used here because of their
  high heat resistance. We are familiar with pottery, tile, crucibles,
  and fire bricks as types of ceramics. They have very high melting
  points and don’t require the cooling systems like those needed to keep
  metals from melting so they make for lighter, less complicated engine
  parts. The down side is that they tend to fracture under stress, so
  engineers seek to create new ceramics composites that incorporate
  other materials to improve properties.

Combustion chamber example

Turbine

High-pressure turbine blade (source: Wikipedia)

  The first set of turbine blades are in the highest pressure, hottest
  part of the gas flow and are generally made of nickel-based superalloy
  or ceramic blades. Unheated outside air is circulated through channels
  inside of the turbine blades to keep them from melting in this extreme
  environment. Further down the engine lower pressure turbine blades
  often sit. Since the gases have somewhat cooled by this point, the
  blades can be made of iron-based superalloy or even stainless steel.
  It is interesting to note that for strength, the metals used for
  turbine blades are often grown as a single crystal. A close look at
  most metals and alloys show that they are composed of crystals (also
  called “grains”), and the places where the crystals meet are called
  grain boundaries. A material is weaker at the grain boundaries than
  within the grains—especially at high temperatures— so turbine blades
  fashioned from metal formed as a single grain (no boundaries) are
  stronger.

See single crystal material (known as monocrystalline material in electronics) .

Turbine example (high pressure stator)

Exhaust

Exhaust from Boeing 787 engine (GEnx, one of the world's largest jet engine - Source)

From FAA Aviation Maintenance Technician Handbook - FAA-8083-30:

  Inconel and stainless steel alloys. The Inconel [nickel-chromium-iron]
  alloys are frequently used in turbine engines because of their ability
  to maintain their strength and corrosion resistance under extremely
  high temperature conditions.

See Inconel details.

Casing

  Although it need not withstand high temperatures like the core of the
  turbine, the materials here need to be strong enough that if a blade
  were to break off it would be contained within the casing and not
  enter the wing or cabin of the aircraft and cause further damage.
  Aluminum or some polymer matrix materials are used as engine casings.


What could cause instant nausea when entering larger passenger planes?

There are a few things that could be causing it but chances are its not the aircraft. When on the ground, with the engines off, aircraft simply have exterior air circulating through them. In the hot weather they are often connected to an external AC unit similarly in the cold weather they are connected to a heater. Cabin smells tend to vary widely and I cant find any data other than anecdotal evidence about how they are controlled and if they are quantified.

Once the engines have started they can use bleed air but if your symptoms are calm after 5 minutes its likely they are still using ground fed air at that point.

You may be experiencing light symptoms of Claustrophobia upon knowing you are entering a small, enclosed space. Some evidence points to the fact this can be cured with repeated exposure so the more you fly you may notice the effects reduced.


How large are the CF-100 Canuck wingtip fuel tanks?

This diagram from the RCAF Canuck Aircraft Operating Instructions states the wingtip tanks could each hold up to 292 imperial gallons or 350 US gallons.


During WW1 Zeppelins began their missions with Hydrogen cells at 33% full. How did this provide enough lift to get off the ground?

The gas bags always contained close to 100% hydrogen. No air was supposed to be in them. On the ground, the bags were only partially filled because of the high air density and pressure. The rest of the internal volume of the Zeppelin was filled with air which could enter and escape the hull through the many gaps and venting openings.
Compare that to a weather ballon. On the ground, the big envelope is nearly empty and only a small bubble of lifting gas (today mostly helium, but hydrogen would work even better) sits at the top. Only that the nearly empty ballon is in clear sight, while in a rigid airship the half full gas bag is hidden behind the rigid hull covering.
One cubic meter of hydrogen weighs only 90 grams compared to one cubic meter of air at 1.225 kg under standard atmospheric conditions. With the same amount of hydrogen a balloon will have the same lift, regardless of altitude, because its lifting gas will displace a bigger volume but the same mass of air as it expands with altitude. With Zeppelins, fine tuning of lift by adding dynamic lift is possible but limited to maybe 5%-20% of the ship's mass (more for smaller and faster ships and at lower altitude). By growing larger, the mass to volume ratio of Zeppelins decreased, so the latest WW I ships could be built light enough to fly with their gas bags only one third full.
Civilian airships rarely flew higher than 2000 m high and had to circumvent higher mountain ranges because they filled their gas bags to maybe 80% on the ground. Flying higher was not considered worth the reduction in payload and fuel that would result from less lifting gas.
Compare that to the wartime Zeppelins. They were in a continuous arms race for higher altitude with the British aeroplanes which were sent out to chase them. And until 1918 the most modern Zeppelin designs  were ahead. The limited altitude of older ships also meant that many were scrapped after one or two years of service. The table below shows the maximum altitude at which the gas bags were filling out the available volume of the ships. The list below gives the maximum altitude of the best ship of each series and the density ratio shows the degree to which the gas bags could be filled on the ground to achieve that altitude. Note that they still carried tons of water ballast and ordnance when flying that high.

LZ 112 tried with speed what could not any longer be achieved with altitude: It had 7 more powerful engines where older ships had only 5 and could cruise at 131 km/h as opposed to the 100 km/h of the older ships. The diminishing returns of flying higher and the stress of spending close to a day at -40°C and without a pressure cabin or a pressure suit made higher flight altitude impossible. What also held progress back was the size of airship hangars: Since LZ 62 the maximum diameter could not grow beyond the 23.9 m of the last wartime ships, so their volumetric efficiency went down when they grew larger by adding length.


Can you identify this aircraft photographed during solar eclipse 8/21/2017?

Based on the second picture and the list of US military jet, I would guess F-22 Raptor, and since this kind of aircraft usually fly by 2, the jet in the first picture is maybe a second F-22.

As for the timing of the shots, the trail we see in the second pic not appearing in the 3rd is telling me they were shot with at least a couple of seconds interval. That would also explain why each jet appears only in one pic.


Can anyone explain what are the apron taxiway and aircraft holding taxiway with an illustration, please?

Apron taxiways are just taxiways, except they are on the apron. They help planes on the apron connect to the main taxiways or the planes on the main taxiways connect to the apron.

I don't know what you meant by holding taxiways, but I assume you meant runway threshold or runway holding point. In that case, here's your illustration:

Notice how the apron taxiways are only on the apron and how they lead to the main taxiways! Also, the blue circled areas are runway holding points.

Legend:
Yellow lines: Apron Taxiways;
Red line: Runway;
Blue circles: Runway holding points;
Orange lines: Main taxiways and high speed taxiway;

Oh, and the high speed taxiway I just mentioned is the slanted taxiway connecting the rwy and taxiway without a holding point. That would answer your Rapid Exit Taxiway question.

Yes your terms are clear, but they are not the exact terms that we use in aviation. I guess that was why that guy said your terms weren't clear. But, I do understand them. It's just you wouldn't use them if you were an actual pilot.


Where is the lateral position of the aerodynamic center?

For a simple tapered half wing the aerodynamic centre spanwise location is at:
$$
y_{ac} = {{b}\over{6}} \cdot {c_r + 2c_t\over c_r+c_t}
$$

where $b$ is the span, $c_r$ is the root chord and $c_t$ is the tip chord.

For a symmetric aircraft it should be at the centreline, since it's the combination of the two identical (but opposite sign) locations.

Source is a aicraft sizing code I wrote some years ago, I remember solving the integral for a simple tapered wing.
Looking quickly at design books I can find the following image in Raymer, hope this helps:


Are there conventions on which side to travel on Victor airways - USA?

If you are flying IFR the FAA expects you to be on the centerline of the airway, as per the FAA's IFR flying manual

  to operate an aircraft within controlled airspace under IFR, pilots
  must either fly along the centerline when on a Federal airway or...

I can't find any references in the Airplane Flying Handbook to airways at all and keep in mind under VFR "see and avoid" is paramount but centerline is generally accepted. If you are flying with any kind of an autopilot/GPS unit thats where its going to put you.

Moving to your IFR example

  And worse, if he were IFR at 6000' and right on the radial, that's
  even closer.

500 is more than enough for the FAA's liking especially when one of those planes is flying under IFR.

  Most airways are eight nautical miles (14 kilometers) wide, and the
  airway flight levels keep aircraft separated by at least 500 vertical
  feet from aircraft on the flight level above and below when operating
  under VFR.

The reality is there is often even more separation since under VFR you are required to stay 500 below the cloud bases which are not always at round numbers you may often end up at the next lowest VFR cruising altitude

It is however, advised that if you are flying IFR but climbing on an airway in VFR conditions you execute gentle banks to look for traffic.


Why are these carrier aircraft landing with the canopy open?

Because it is the standard operating procedure, not only for this aircraft, but also for others. In the book U.S. Naval Air Superiority: Development of Shipborne Jet Fighters - 1943-1962, [Tommy H. Thomason notes](By Tommy H. Thomason):

  Leaving the canopy open for landings and takeoffs would still be standard for many years as it facilitated egress in the event of a water landing.

Here's the Grumman F9F Panther, one of Navy's first jet fighters landing with its canopy open:

Grumman F9F-5 Panther, Bu. No. 126034, of VF-781, catches an arresting cable when landing aboard USS Oriskany (CVA-34), 15 November 1952. (U.S. Navy); image from thisdayinaviation.com

This followed through the time of Cutlass, as thanlont.blogspot.in notes:

  The ... F7U pilots all have their canopies open for landing. Although open canopies for carrier takeoffs and landings had been standard since canopies were introduced, this became pilot's choice on straight-deck carriers at some point following the addition of the barricade ... after an incident or two when the upper strap of the barricade went into the cockpit of a crashing jet. Note that the FJ-3s are taking off with open canopies.


Would flying below FL285 be feasible for aircraft that don't comply with EASA CPDLC?

Unlikely. The extra fuel burned would cost a lot more than the required Avionics upgrade.

Both the 75/767 would be well below optimum cruise level.


No, your assumption is not correct. Airspace boundaries are not defined by waypoints, but by WGS84 lat/lon pairs, which you can probably just use directly without a lot of manual work.

You need to consult the national Aeronautical Information Publication (AIP) for the country in question to get the coordinates for their national airspace, called a Flight Information Region (FIR). Specifically, look in AIP section ENR 2.1 (all AIPs worldwide are structed in the same way). Here is an example for the UK: https://www.aurora.nats.co.uk/htmlAIP/Publications/2020-03-26-AIRAC/html/eAIP/EG-ENR-2.1-en-GB.html#ENR-2.1

I recall having downloaded a global file with FIR coordinates for the entire world somewhere off the web, although I don't remember exactly where. It may well have been published by the ICAO. You might be able to locate it if you look around a bit.


What type of visa do pilots who fly from one country to another need?

International Airline crews often spend 1 or 2 days laying over at the destination. In most countries, airline crew members who are listed on the Aircraft Customs and Immigration General Declaration are exempt from Visa requirements.
Rules will vary from country to country as to how much travelling freedom you have while staying in the layover country. Most countries require you to always have your passport with you and some countries require some kind of form identifying you as airline crew. Some countries have rules defining how far you can travel while on the layover.
In general practice most airline crews I know leave their passports in their room and just carry a photo copy or digital copy with them, and freely travel just as any tourist would do.


Launch control equivalent while take-off

The term I'm coming across the most is "static take-off" (even used by Airbus).

Its advantage is that it's using the least distance since you don't "waste" the distance it takes the engines to spool-up (in a jet anyway) to take-off power.

Not to be confused with "non-rolling take-off", which just means the aircraft was holding on the runway before the take-off run started. A non-rolling take-off is not a "static take-off" if the pilot didn't step on the brakes until the engines spooled up.


The swept-back wingtip has been successfully employed by water fowl for many millennia. The use of composite structures has made the three-dimensional shaping of wingtips much easier, and the first airplanes to use increased sweep at the wingtip were indeed composite gliders such as the Schempp-Hirth Discus.

Seagull (left) Schempp-Hirth Discus 2 (right, source)

In the times of metal wings, Dornier introduced their TNT (Tragflügel Neuer Technologie, in English: Wing of new technology) on aircraft like the Do 228, Do 328 and the Dornier ATT flying boat. It used a triangular wingtip with no change in trailing edge sweep, which is easier to manufacture in aluminium.

An Air Alps Dornier 328-110 landing at Fiumicino Airport, Rome, Italy, viewed from Ostia Antica. Picture by Makaristos.

Boeing has now introduced this detail as the "raked wingtip" in the 787 and the 747-8. Compared to a straight wing, a swept wingtip offers some benefits;

Higher sweep lowers the lift curve slope. This helps to reduce the lift contribution (and, consequently, the bending moment!) of the wingtip at high angles of attack. Therefore, raking the wingtip will result in a lower maximum bending moment.
The sweep also shifts the center of pressure of the wingtip backwards, adding a negative torsion moment. This moment lowers the angle of attack over the whole outer wing in gusts and at high load factors, again helping to lower the maximum bending moment at the root.
It allows to combine a near-elliptical circulation distribution over a wide range of angles of attack with good stall characteristics. The lower lift curve slope of the wingtip lets it stall at a higher angle of attack and reduces its lift contribution relative to its area at increasing angle of attack.

In order to prevent the outer wing from stalling first, you want to give it a lower lift coefficient, which can be achieved by locally adding chord over what is required for an elliptical wing planform and a lower local incidence. However, doing so will still add lift proportional to the local chord when the angle of attack is increased. Now the wing will show the ideal elliptic circulation distribution only for one angle of attack. By adding sweep to the outer wing, its lift curve slope is reduced, so its off-design circulation distribution is closer to the elliptic ideal.


Does "nose dive" have a technical aviation meaning?

Are there types of dives which do not involve a nose-down attitude?

Yes (although these are not always intentional): a graveyard spiral can occur without a nose down attitude. You can also stall a plane nose high and begin diving to the ground maintaining a stalled nose high attitude, this is similar to what happened to AirFrance 447. A flat spin will also result in "falling" vertically with a relatively flat nose attitude.

In my experience "nose dive" and "dive" are generally interchangeable.


How can I know if the Garmin GTX 345 transponder supports modes A and C?

It's on the spec page: Garmin GTX 345:

Physical dimensions (unit, rack, connectors); for panel mounts, depth is measured from face of instrument panel): 1.65” x 6.30” x
10.07” (42 x 160 x 256 mm)
Display type: Digital
Weight (unit, rack, connectors): 3.1/3.2 lbs (1.41/1.45 kg)
Voltage range: 14/28 VDC (18/20 W Max)
Transmit power: 200 W minimum
Temperature: -40° C to +70° C
Operating altitude: To 55,000 ft (16,800 m)
Cooling input: Not required
Environmental compliance (TSO Approved): DO-160G
Software compliance (TSO Approved): DO-178 Levels B, C, D, E
Hardware compliance (TSO Approved): DO-254 Level C
TSO compliance (Approved): TSO-C88b (w/opt. alt. encoder; TSO-C112e (Class 1, Level 2els; TSO-C154c (Class A1S); TSO-C157a (Class 1);
TSO-C166b (Class A1S); TSO-C195a (Class C1,C2,C3,C4)
Mount type: Panel
Transponder type: Mode A/C, S and ES
Squawk code selection: Push-button
Traffic Information Services (TIS) alerts compatible: Yes

I have one of these units, and I can confirm that it supports A/C, S, ES, and ADS-B.


Which airports have the highest fuel upload?

The best data I could find is in this paper about biofuels, which has data for US airports in 2014. Based on my reading of the chart on page 14 and some conversion:

Airport  Millions of barrels per year
KLAX     48.6
KJFK     43.5
KATL     30.8
KORD     30.5
KSFO     28.3
KMIA     26.0
KDFW     25.4
PANC     19.0

Comparing this to the top US airports in 2013, it is interesting to note that LAX and JFK use significantly more fuel than KATL, despite passenger traffic figures ranked the other way. Also notable is Anchorage showing up here right after DFW, while MIA and ANC are the only ones not in the top 10 by passengers, showing up at 11th and 58th, respectively.

Figures for other countries have been harder to find. This article from 2004 estimates the Dubai International usage at 24.2 million barrels that year, which has certainly grown since then. The 2012-2013 environmental report from Emirates Group lists their consumption at 73.9 million barrels, and half of this figure would be in line with the other numbers available.

I found a similar figure for Heathrow, listing it at 20-25 million liters per day, depending on season, which gives a range of 61.2 to 76.5 million barrels per year, well ahead of the US airports.

Becoming even fuzzier, the pipeline to Narita Airport in Tokyo transported 130 billion liters in its first 30 years of operation, which averages out to 36.3 million barrels per year.


How are the services kept running on a plane without an APU?

The aircraft is connected to a ground-based supply.

The ground-based air conditioning is connected using a large yellow pipe, and electricity is connected using a set of cables. In the photo below you can see both connections.

image source

In the cockpit, the pilot can select the power source for the aircraft. The proper procedure is to start the APU before disconnecting the ground power supply, otherwise the whole cabin will go dark once ground power is switched off! If you are a passenger boarding, you may have noticed that the cabin lights flicker for a very brief moment. This is when the power source is switched from ground power to APU, as part of the start up procedure.

If the APU is inoperative, things get a little complicated. Typical electricity source include ground-based supply, APU, engines and battery. The battery is only a backup for very essential flight instruments; it is not even capable to
power everything in the cockpit, let alone the cabin. The ground-based supply unit must be disconnected before the aircraft starts moving. So that leaves the engine(s) as our only power source.

However, getting a turbine engine started without an APU is a tricky matter in its own: it requires another ground-based unit to blow air into the engine. The only remaining option is to keep at least one engine running during the turnaround, since the running engine can be used to power up all other engines, at the expense of fuel.


From YouTube

After scouring the internet, the device seen in the first two pictures is indeed a clock.

In the linked video the display does count up like a clock. In the beginning of the video the narrator says, "it's just after 4 AM in Seattle," and the displayed time is 04:17:58.

Watching the maiden flight of the A350, no similar device is found.

I then turned my attention to the FAA's Flight Test Guide For Certification Of Transport Category Airplanes, there's no mention of such a device being mandatory.

Closest thing I found is a requirement to video record and timestamp spin tests in light aircraft.

The timestamping theory would make sense if the video recording of the cockpit is high speed, which would be overkill for any scenario really.

Time synchronization for the flight test instrumentation data acquisition is a real, and complicated thing.

My theory, showing the pilots the master clock—if that's the case—would help the pilots note the time when a situation arises so the engineers can check the relevant data.

It might also have other functions as recording total elapsed time of the entire flight test program for the airframe it's installed on.

I've also looked into trajectory guidance systems for test pilots based on true airspeed/pressure measurements being fed to the pilots, but such systems turned out to look completely different than a seven-segment display.

Over to you.


Is there's any risk using modern C++ compiler on DAL A Display Application Flight Software?

The issue with many things in flight safety is that the status quo is well understood. Changing something introduces a whole body of unknowns, and considerable circumspection will be applied by the people charged with ensuring safety. This is why piston engines in many light planes are almost identical to those used half a century ago - they're known to work - and why there is considerable inertia when it comes to updating your software tools.

Ultimately, the only way things are likely to move is when somebody builds a case for updating the tools that shows sufficient commercial benefit to overcome the additional cost of certifying the final product.

It won't be enough to simply argue that a new compiler has this or that set of new features. You'll need to demonstrate that using the new compiler will allow you to provide a set of new features that you can't provide with the old one, and that this will lead to a tangible increase in sales.

Good luck!


Is a non-WAAS Garmin 530 certified for an LNAV/VNAV approach?

It seems if used on its own, the 5xx is not capable of LNAV/VNAV approaches.

Source: garmin.com — scroll down to the link that reads: "Garmin Flight Plan Information Excel file".


How is the effect of wind on arrival time handled?

It will depend on constraints at the arrival airport. If there are no constraints, they will choose a speed that minimizes fuel burn, and arrive early if that's how it works out.

It's possible that the arrival airport may have constraints on arrival volume. As you pointed out, for busier areas, if aircraft arrive earlier than expected, it could cause things to get backed up. In that case ATC may have an aircraft adjust their speed or enter a hold in order to delay their arrival until capacity allows. Slowing down early is more efficient than arriving too soon and having to fly a holding pattern.

In areas without radar coverage, such as oceanic crossings, aircraft may be required to hold a certain airspeed in order to maintain separation from aircraft ahead and behind. In this case a pilot may not have much choice until they exit the oceanic airspace, and any adjustments would have to be made after that point.

ATC will do their best to ensure the safe and expeditious flow of traffic, but safety has to come first. While a pilot can choose to not follow ATC instructions in the case of an emergency, and in the interest of safety pilots have some amount of discretion in declaring emergencies as they see necessary, doing so just to reduce cost or for convenience would not be acceptable and may attract some scrutiny.

It's also possible that there would be constraints on the ground at the arrival airport. If the aircraft is scheduled to arrive at a certain gate at a certain time, and it arrives early, there may be another aircraft still occupying the gate, or support staff may not be ready to receive the aircraft. This would require the pilots to coordinate with the airline. If alternate arrangements can't be made, the airline might actually prefer the aircraft to be not arrive early. They would probably prefer to sit on the ground, with the engines off if possible, as that burns much less fuel than doing the waiting in the air.


Why don't airliner winglets have consumer advertising on them?

Why airlines don't put third-party ads on winglets

I would assume that a significant part of the answer is that it would look and feel cheap (i.e. not good for the airline's brand image.) They don't usually sell advertising elsewhere on their livery for much the same reason (though they do occasionally dedicate a livery to advertising some charity or some such thing, but that doesn't normally hurt their brand image.) On the other hand, putting the airline's brand image there can possibly help to improve it.

While you are already on the airline's flight, they'd be quite happy if you purchased more flights with them in the future and even more happy if you purchase the tickets directly from their website where they don't have to share the revenue with a travel agent. An additional benefit of mentioning the website is that many airlines now have on-board Wi-Fi and allow you to access their website from it even if you haven't paid for the Wi-Fi. As such, if they can get you thinking about their website and you happen to hop on it and book your next trip while cruising around at 30,000 feet, that's a win for them.

Finally, while they do already have you on board, they're well aware that lots of people post pictures taken while they were on a flight, especially pictures that include the wing (such as the one in the question.) Now your pictures are free (and usually positive) advertising for them.

Vinyl Wraps / Decals

As far as wraps are concerned, as far as I know, yes, they're legal and actually pretty common, even for the fuselage livery. My understanding is that lessors use them pretty frequently. They've also been used for temporary liveries like this one:

It appears that several companies exist for the sole purpose of making aircraft wraps. A quick search found the following:

AdGraphics
AircraftWraps
Plane Vinyl

It appears that 3M makes a lot of the materials used for the wraps.

I also found an FAA document on aircraft coatings that talks about how to apply vinyl decals to aircraft (along with how to paint aircraft, etc.) From page 18:

  Vinyl Film Decals
  To apply vinyl film decals, separate the paper backing from the plastic film. Remove any paper backing adhering to the adhesive by rubbing the area gently with a clean cloth saturated with water. Remove small pieces of remaining paper with masking tape.

  Place vinyl film, adhesive side up, on a clean porous
  surface, such as wood or blotter paper.
  Apply recommended activator to the adhesive in firm,
  even strokes to the adhesive side of decal.
  Position the decal in the proper location, while
  adhesive is still tacky, with only one edge contacting
  the prepared surface.
  Work a roller across the decal with overlapping strokes
  until all air bubbles are removed.

This page from signindustry.com goes into more detail about how to apply vinyl decals to aircraft from a professional installer standpoint.


How does the EPR reading behave in reverse, and in reheat modes?

What is EPR?

[It] is the total pressure ratio across a jet engine, measured as the ratio of the total pressure at the exit of the propelling nozzle divided by the total pressure at the entry to the compressor.

Placing an EPR probe in the A/B (afterburner) tube would not be a wise choice, and therefore in an A/B aircraft you wouldn't find an EPR reading. What is more useful is the NP (nozzle position). As that is a good indication of A/B level. N1 is still used of course.
In the civil world, GE and CFM don't have EPR sensors/readouts, unlike P&W and RR.
Not having an EPR avoids issues like EPR probe icing. But the downside is that it's harder to compute engine FADEC parameters.
More info here: What is the difference between EPR and rotor speed as thrust setting parameter?
Below are the F-14 engine instruments (analog tapes and dials are also present in the cockpit).
TBT is turbine blade temperature. EGT is also not used as it too would not survive the A/B stream.
EPR and Reverse
On the Boeing 747-400 with RR or P&W engine options, the EPR window is blanked when reverse is activated.
What the engine is redirecting is the bypass flow. So the EPR will still read as normal, which can be quite confusing to the crew especially in max reverse, hence the blanking.


Why is the wing bending so much in this video?

Because that wing is a cantilevered beam which is now supporting over half the weight of the jet on it.  This causes the wing to flex, much like a leaf spring, when loaded.  While fascinating to watch this is benign and designed to do this.  In addition, this wing flexure helps to absorb bumps, air turbulence, dampen flutter, maneuvering loadings, etc. much like the coil springs in your car's suspension do.  Don't be alarmed to see this.  Those wing structures have been tested to far worse loads and conditions that you will ever see on a revenue carrying flight before failure occurs.  A 747's wingtips can flex by as much as 12ft up/down during flight.  Newer composite wings are capable of much greater flexure.

This was video shot of Boeing's destructive testing on the 777 wing.  Note the wingtip flexes by as much as 20ft upward at a loading over 150% that of its design load limits before structural failure occurred.


What is this aeroplane - not a Blackbird?

The large aircraft is the Lockheed M-21 (which was developed from the Lockheed A-12, the same aircraft that the SR-71 was developed from), and the smaller aircraft is the D-21 drone.

The wikipedia article on the D-21 has a lot of information.


Is there a type of instrument/display that guides pilots along a certain path?

What you are describing is a Course Deviation Indicator or CDI.

These are fairly standard across most aircraft however they may also be combined with a heading indicator resulting in an Horizontal Situation Indicator. There are also variants that have an aircraft symbol such as you describe.

Depending on how your aircraft is setup these units can be referenced off a radio beacon such as a VOR an ILS system for approaches or a programed GPS route.

This video covers some basic operation if you are curious.

A lot of GPS units with moving maps are generally able to display the info you describe as well.

There are even various apps that allow you to display such info on your tablet or smart phone


For a modern airliner, wings are tested to withstand 150% of the limit load. What kind of weather would produce turbulence at 100% limit load?

The 1.5 relates to the margin between permanent bending (limit or yield load) and breaking (ultimate or breaking load).  Transport Airplanes are good to 2.5 limit load at gross weight.  Pulling more than that may or may not bend the wings permanently.  For ultimate load (pulling the wings off, it's 3.75Gs minimum using the normal 1.5 safety factor)

Those are minimums.  There is a lot of safety margin in the stress calculations so I would not be surprised at all to see an airliner take 3Gs without permanent damage even at max gross.  If the airplane is below its maximum zero fuel weight (a function of the pax and baggage load, which is where the wing bending is coming from) there is more margin, depending on how light you are.

Then there are the two speed limits to protect the structure to consider.  Maneuvering speed is the speed below which a sudden maximum elevator input will reach stalling AOA (thereby unloading the structure) before limit load is reached.  Turbulent Air Penetration Speed (TAPS) is the speed below which a theoretical worst case vertical gust will cause stalling AOA to be reached before limit load is reached.

As far as weather conditions, the biggest risk is flying into a thunderstorm cell and hitting extreme vertical gusts (mainly the up going air shaft in the center of the cell), and next to that would be Clear Air Turbulence which is usually related to crossing jet streams and passing through the shearing turbulence sometimes caused at the boundary between the jet stream and the adjacent air mass (jet streams reside in the little corner at the very top of a frontal boundary, in a little triangle of space at the top edge of the warm air mass, next to the adjacent cold air mass and the stratoshere above).  Another one is crossing rotors (spinning horizontal shafts of air) that reside below the crests of mountain waves that form downwind of mountain ranges at high altitudes.

For that eventuality you have to slow to TAPS any time you expect to hit severe turbulence like picking your way around thunderstorm cells or flying into areas where Clear Air Turbulence is reported.  In the absence of a CAT report, a cautious capt may slow to TAPS anyway if the crew notices that they are passing across a jet stream, just in case (you know you are crossing a jet when your ground speed suddenly changes and the autopilot starts making a sudden heading change to stay on track - it all goes back to normal when you leave the jet).

In theory, staying below TAPS provides protection against permanently bending the wings same as staying below MS protects from bending the wings from a full on elevator input.  If the 777 in the incident hit 3 Gs, it suggests that they were above TAPS when it happened but even if it was fully loaded, with the fudge factor in the structural design it's not surprising it wasn't bent from an encounter only half a G above limit load.


Does a jet engine keep running when it can no longer be controlled from the cockpit?

General rule here: the engine will remain at its last power setting should the FADECs lose comms with the flight deck controls (in your A380 case) or the thrust lever cables come unhooked (in the case of an older aircraft with mechanical cable-and-pulley controls).

However, the fire handle will kill the engine even if the main controls fail -- it operates the firewall fuel and hydraulic shutoff valves.  In QF32, this didn't happen because the cable for the #1 engine fire handle itself was damaged by shrapnel entering the wing.


Is there a triangle representation for the Canadian airspace?

I did not find a triangle representation, but this poster summarise the particularities of the Canadian airspace

https://www.tc.gc.ca/en/services/aviation/documents/TC-6010-AirspacePoster-E.pdf


Which incidents did not result in accidents because of the actions of the second pilot on board?

During the 2005 Logan Airport runway incursion, the First Officer noticed the other plane and realized that they could collide. Telling the Captain to "keep it down", he pushed the control column forward and passed under the other aircraft as it took off.

During United Airlines Flight 232, the actions of the flight instructor for the type, Dennis E. Fitch, brought in additional expertise that significantly contributed to success. E. Fitch joined the crew during the flight as an additional pilot.

On the day before Lion Air Flight 610 crash, that plane, already with problems, has been saved by off-duty pilot who correctly identified the problem (and suggested to disable the flight control system).


How can I know if a landing exceeds the hard landing threshold for a Cessna 172S?

Was it uncomfortable or did it hurt?

If it hurt you, it probably hurt the plane. That 500 pound engine is hanging a foot and a half from the firewall by four bolts. It's not hard to cause some damage.

Anyway, if you think it needs to be checked, just say something to the mechanic. It's not that time consuming, and it's better to be safe than sorry.


What happens when an airplane gets struck by lightning?

The vast majority of aircraft require an inspection, from small Cessna singles to Boeing airliners. Usually, they require at the very least:

A visual inspection of the aircraft for damage, particularly the nose, tail section and wingtips. Most of the time, the damage is easily visible as "burn" marks or erosion of parts of the skin.
A check of the communication/navigation systems, both visually and functional testing
A check of all avionics, including GPS systems
Propeller should be removed and inspected by an A/P for damage
Engine should be inspected by a procedure similar to the following:

Remove the engine from the aircraft and disassemble it.
Inspect the engine for arcing and heat damage to the crankshaft,
main bearings, counterweights, camshaft lobes, bearings, gear teeth
and any other parts applicable to your engine. Any magnetic parts
should be degaussed following the specific procedure in your manual.
Measure each other part to make sure it is within tolerances for your engine.
Reassemble, then install the engine.

(depends on company) Send in an lightning strike report to your manufacturer
Confirmation of compass being within 10 degrees of another (stricter for transport low visibility operations) after completion of repair/inspection works

Sources:

Cessna 172R Maintenance Manual
Aero Magazine -- Lightning Strikes: Protection, Inspection, and Repair (Boeing, Q4 2012)
Continental Maintenance and Overhaul Manual: M-18


How should the pack flow knob be set on an Airbus A320?

No. Assuming there are no regulations, you can set it anyway you want, at an expense of fuel consumption.

Do not confuse Ventilation control with Temperature control. Temperature control is another setting. (via Cockpit overhead/FAP)


Do you need strong muscles as far as applying the yoke is concerned, in order to be able to deal with some emergencies?

For the Airbus it is not actually require any strength, all the technology is fly by wire, this means that the actual control (Side stick) is not directly connected to any cable, so been this said, there is no actual force to fly any airbus plane. For the Boeing plane, at least for the 737, that's the one I know, when it loses all the hydraulic systems, the aircraft will become on a manual reversion mode and it will need strength from the pilot to move the aircraft controls that are linked to the surfaces by cables, but this is a remote possibility to happen, and if it is the case both pilots can apply force to the control column


Has anyone ever been penalised for buzzing a control tower?

Well, there's always someone.In January 1954, American TV and Radio personality Arthur Godfrey buzzed the Teterboro control tower with his Douglas DC-3, resulting in the suspension of his license:

In the mid 1950’s, Arthur Godfrey was preparing to take off from Teterboro Airport in his private DC-3. He requested a take off on a runway which was into the wind.  The tower refused his request and instructed him to use a runway which had a sizeable crosswind. He complied, but he buzzed the tower, almost running into it. The tower personnel dove for cover and reported him. After a long hassle, Godfrey had his license suspended for six months.

And he wrote a song about it.
Back then, you lost your license. If you try that stunt now, your chances of ending up in a black site are frighteningly real, as Shaun Lees, an amateur pilot found out:

... (Lees) chartered the helicopter from another airport, landed at Coventry, where his actions effectively closed it down, then flew toward the control tower.
Hovering close to it, he announced over the radio, "you are going to see the very worst of my flying", then started to circle.

He got sent to the jail for three years, with

... Judge Marten Coates told Shaun Lees, a 41-year-old electrician, what he had done was "practically an act of terrorism".


What are the differences between a helicopter engine (turboshaft) and an aircraft engine (turboprop)?

There are no major differences between a turboprop used on an airplane and a turboshaft used on an helicopter. All power is collected by the turbine shaft which rotates the blades through a gearbox.

An example of a gas turbine used in helicopter, airplane, train, and even snowplow is the well-known Pratt & Whitney PT6. It has different versions. The two versions shown below are the PT6A for a propeller (top), and the PT6B for an helicopter (bottom, with a large gearbox). Each sub-family has variant for different powers.

(source)

(source)

On the two images, from right to left: The accessory box powered by the compressor section, the air intake recognizable by its filter, the compressor (not visible), the combustion chamber (yellow color on the bottom image) with its circle of igniters, the turbine (not visible), the exhaust (the big hole, best visible on the bottom image), the power gearbox with different output shafts.

There are different types for aero-engines, including turbojet, turbofan, turboprop and turboshaft (I exclude the ramjet which is not used in civilian aviation).

All types are based on a gas turbine, but the way the turbine participates to the motion is different.

(source)

While airplanes use all types, helicopters cannot use the jet action/reaction principle (tip jet excluded for simplification).

The gas turbine can be the same for turboshaft and turboprop engines, but will be fitted with appropriate elements:

The rotational speed of the shaft will be adjusted to accommodate the rotor or the propeller. This is done using a gear reduction system. An helicopter rotor turns slower than an airplane propeller.
Air intake and exhaust are adapted. It rather common to have the air intake on the opposite side of the power output shaft. For a pulling propeller, this means the intake will be aft, and air must be collected forward and ducted to the engine intake.
The power output shaft is usually used to bear the propeller tension caused by the lift, while on an helicopter, the rotor tension is borne by the frame.
The accessory box is usually powered by the compressor side of the engine.
A turboshaft don't provide the bleed air extraction, there is no cabin pressurization required.

(source)

Gas turbines used in both cases are frequently free turbines, where the compressor section and the turbine (power) section rotate independently of each other. This allows to produce electricity or hydraulic power on the ground without turning the blades.


Why are adjustable area jet engine nozzles mostly limited to military use?

A variable area nozzle helps to adjust the exit pressure of the combustion gases to ambient pressure. When they leave the turbine, the combustion gases have still some remaining pressure which is converted into speed by a convergent contour of the nozzle.

If the combustion gases have enough pressure to be accelerated to supersonic speed, the nozzle is actually first convergent and then divergent to achieve the best acceleration of the flow. The convergent, subsonic flow accelerates until in the section with the smallest area, called the throat, the speed of sound is reached, and the following divergent section accelerates the now supersonic flow further until its pressure drops to ambient pressure. This con-di-nozzle needs to adjust both the cross section of the throat and the cross section of the exit area. Failure to get especially the throat area right will mean substantial thrust loss in operation.

Afterburning engines need adaptable nozzles due to the different operating conditions in dry and wet mode, so they profit the most from adjustable nozzles. Reheating the exhaust gas means to increase its volume, so the nozzle needs to become wider to be properly matched. In general, if the exit speed of the combustion gases is supersonic, an adjustable nozzle is required. Even some early jets without afterburners had an adjustable nozzle: The central cone of the Jumo-004 nozzle could be moved fore and aft, which changed the location of the bulbous aft section, helping to get the throat area right. Note in the picture below that the cross section widens again in the last part of the nozzle, which shows that the exhaust stream of the Jumo engine was mildly supersonic.

Airliner engines would only gain little from an adjustable nozzle, and considering the mass increase of a fully adjustable nozzle, would in total have lower efficiency. Short-range aircraft usually have nozzle geometries optimized for field performance while long-range aircraft prefer to optimize for best cruise efficiency. Their core flow exit speed is still subsonic or only mildly supersonic - please note that the speed of sound in the heated combustion gas is much higher. At 500°C the speed of sound is almost 560 m/s.

The variable area fan nozzle tries to do for the fan flow what the regular nozzle does for the core flow of a jet. So this is indeed a related concept and helps to optimize performance both at low and high speed. The picture below is copied from the US patent 2011/0302907A1 and shows an adjustable end part of the cowling (crosshatched, 54). The exit speed of the fan flow is subsonic at take-off and mildly supersonic in cruise, and since its mass flow is much higher than that of the core in airliner engines, making the nozzle variable pays off earlier. By adjusting the exit pressure by varying the exit area it can squeeze out some performance gains.


Is recurrent simulator training required every 12 months whilst acting as SIC under Part 91?

The only Part 91 recurrent training and testing requirements are in subpart K, so if they don't apply to you then only the general currency requirements in Part 61 would apply.

The SIC currency requirements in 61.55 are (every 12 months):

  (1) Become familiar with the following information for the specific
  type aircraft for which second-in-command privileges are requested—

  (i) Operational procedures applicable to the powerplant, equipment,
  and systems.

  (ii) Performance specifications and limitations.

  (iii) Normal, abnormal, and emergency operating procedures.

  (iv) Flight manual.

  (v) Placards and markings.

  (2) Except as provided in paragraph (g) of this section, performed and
  logged pilot time in the type of aircraft or in a flight simulator
  that represents the type of aircraft for which second-in-command
  privileges are requested, which includes—

  (i) Three takeoffs and three landings to a full stop as the sole
  manipulator of the flight controls;

  (ii) Engine-out procedures and maneuvering with an engine out while
  executing the duties of pilot in command; and

  (iii) Crew resource management training.

Practically speaking, what the FAA requires is only part of the picture because your insurance company will probably mandate certain training and currency requirements that may go well beyond the regulations.


The crew of Rockwell B-1 Lancer (4 in total) enter or exit the cockpit from the underside, using a ladder. It can be seen in this video.

This picture shows the ladder (the one on the right):

Image Source

On the top of the ladder, there is a door, which looks like this:

Image Source


Why was the Bell Boeing V-22 Osprey not worked on more?

The Osprey has arguably been quite successful considering the circumstances. As Energizer777 points out, the basic idea is not new, and there were many engineering challenges to create a viable aircraft. That these challenges were solved and the plane is now in production and active service seems to be a pretty big success. Also, this has all happened relatively recently. The V-22 first flew in 1989 while the F-15 and F-16 both date back to the early 1970's (and are still in active service). The challenges in refining the design pushed introduction of the V-22 out until 2007. The design just hasn't had enough time to mature past the first successful application. You might consider the civilian tilt-rotor AW609, currently targeted for certification in 2017, as the next advancement of the design.

Props/rotors are more efficient than a jet engine at low speeds. Given that the slow and vertical portions of the flight are very important to the design, this decision makes sense. The prop wash also flows over the wing, allowing the wing to be more effective with a short span. Using turboshaft engines rather than jets also allows one engine to drive both rotors if the other engine fails, making single engine operation easier.

You are right about the drawbacks of the design. The V-22 is noisy and not as agile has a helicopter in slow flight. Maintenance requirements are high and were certainly an issue early on in the introduction to service. And upfront costs are also more than a helicopter or airplane of comparable size. However, the capabilities you listed first are worth these added costs, at least to those that have purchased/ordered the V-22.


Can autothrust keep the plane aligned with the runway during crabbing?

EDIT: I take your question as "when crabbing the aircraft for landing in strong crosswind, is the auto-thrust precise enough to maintain horizontal alignment with the extended runway centerline?"

No. Auto-thrust is not precise nor responsive enough for this capability. Furthermore, auto-thrust is not used in this manner. To track the extended runway centerline when the crosswind changes, the pilots would increase or decrease the crab angle using rudder inputs.

Let us for a moment consider using auto-thrust to track the centerline. As an example, imagine an aircraft landing on runway 36 (pointed North) with a strong crosswind blowing East to West. The plane's heading will be somewhere between 360 and 90 degrees, while its track is 360. Suddenly, the crosswind increases, and the plane experiences a deviation to its left.

The plane is drifting to its left because the velocity component in the East-West direction is nonzero. If this is countered by increasing engine power, the plane can, theoretically, increase its velocity component pointing towards the East and get back on track. The problem is, flying a plane is three-dimensional! If engine power is increased, airspeed will increase, lift will increase, and the plane will drift above the glide slope vertically.

The correct response is this case is to input right rudder. Staying on localizer and glide slope requires frequent, precise but small changes. The right tool for that is the control surfaces. When using the crab technique in a crosswind landing:

Elevator is used adjust the plane's vertical speed
Rudder is used to adjust the plane's crab angle
Ailerons are used to maintain the wings level (to counter the aircraft's tendency to bank when using rudder)
Thrust is used to maintain airspeed (which keeps the plane from stalling)

From your question, it appears that you may have some misconceptions.

Thrust is forward. It controls the airspeed, which is also related to the angle of attack. Crosswind is wind blowing either left-to-right or right-to-left. Therefore, thrust and crosswind are unrelated; auto-thrust will not compensate for crosswind because thrust can only make the plane go faster/slower or go up/down, but crosswind blows side to side.

If your question is whether the autopilot uses asymmetrical thrust to control the plane in these conditions, then the answer is no: thrust is not responsive enough to control a plane's attitude, asymmetrical thrust is only used in emergency situations when no other options are available.

My bet is you're asking about gusts and wind shear, which can be experienced as either a headwind, tailwind or crosswind, so it may affect an aircraft's airspeed. Wind shear is defined as a sudden change of wind speed and/or wind direction.

The calculated speed of a landing is called Vref. In a normal landing, the pilots usually input Vref+5 into the autopilot. In gusty conditions, the pilots may input Vref+10 into the autopilot. A less flap setting may also be selected, again for the purpose of flying the approach at a higher airspeed. A higher airspeed is desired because it increases the stall margin.

  When using the autothrottle, position command speed to VREF + 5 knots.
  Sufficient wind and gust protection is available with the autothrottle
  connected because the autothrottle is designed to adjust thrust
  rapidly when the airspeed drops below command speed while reducing
  thrust slowly when the airspeed exceeds command speed. In turbulence,
  the result is that average thrust is higher than necessary to maintain
  command speed. This results in an average speed exceeding command
  speed.

  If a manual landing is planned with the autothrottle connected
  in gusty or high wind conditions, consider positioning the command
  speed to VREF + 10 knots. This helps protect against a sudden loss of
  airspeed during the flare.

quote from Boeing 777 Flight Crew Training Manual

Auto-thrust itself is precise enough to handle gusty winds to an extent, but it has its limitations. IIRC using auto-thrust is recommended in these scenarios, as it reduces the pilots' workload in a challenging situation. Plane manufacturers and airline companies often have limitations regarding the maximum gust / maximum crosswind. Attempting a landing outside these limitations may exceed the auto-thrust's capability to respond to rapid airspeed changes; it may also exceed the landing gear's strength or the wing's loading and therefore is dangerous.


Why aren't flights continued after losing a tire on rotation?

Blown tire - can't raise gear, shredded tire will not fit in the bay.    ->

Gear down - much lower maximum speed and lots of additional drag ->

Both of those mean very poor fuel economy ->

Very poor fuel economy means not enough fuel to reach destination

So that's off the table.  Given that, there's no question that it's better to follow the safest course... And you had an extremely high pressure tire just explode, a couple feet away from the airplane's skin.

Especially when that brings you back to a field that is in fact an operating base for that airline, and is likely to have inspection and repair services, and may have a spare airplane.  I could see a Southwest flight out of SJC diverting to nearby OAK, since OAK is a main operating base for Southwest and will have an easier time fixing or replacing the aircraft.


Can two Airlines have the same ICAO code but different IATA codes or vice versa?

IATA codes are not unique. There simply aren't enough of them and they are expensive to maintain. Additionally the concept of an airline is a little fluid.

The simplest issue to deal with are controlled duplicates, where 2 airlines that are geographically seperated share an IATA.

Another key issue is where an airline may have one commercial brand but several corporate entities each with there own IATA for cabotage purposes. LATAM group is a key example of this, but several european airlines (easyjet and ryanair) are also going down this route to be prepared for brexit.

Many small regional airlines in places like Alaska,the Australian outback and the Caribbean will simply not be able to afford an IATA code, or may make up there own 2 letter code that is not an IATA code.

Finally you have franchise operators like flexflight, who operate a single route themselves to maintain membership, and then provide ticketing services to other small airlines, using there code to interact with the GDSes. In this case, one IATA code can represent many potentially geographically overlapping airlines, but they are usually separated by something, often flight number.

If you wish to track all airlines in general, you are going to have to come up with your own id.


Are you required to have constant view of the runway when circling?

A "circle-to-land" maneuver is basically a low-altitude traffic pattern - albeit one that you arrived at by being guided in on some instrument approach. The magic that makes this low (and possibly abbreviated) pattern possible is that the runway ends at airports with circling approaches have protected (obstacle free) airspace around them, which looks something like this:

(A more detailed explanation of the size of the circling approach area can be found on this question.)

Since it's basically a traffic pattern my understanding is you treat it as such, and that as long as you stay in visual contact with the airport and within the protected airspace (by visually judging your distance from the field, and knowing your altitude) you're unlikely to hit anything, and you can do all your usual pattern maneuvering as long as you can ***visually* be sure you're within the pretty blue part of the image above (your GPS cant help you here).

To see what this means for an example approach with some turns, consider my liberally-stolen and slightly-marked-up diagram below.

If you lose contact with your intended runway end for a few seconds because of the turn/bank required at point "A" that's OK: as long as you can still maintain visual contact with the airport/runway environment when you roll out (say by looking out the back window), and as long as you can remain clear of clouds, and can maintain visual clearance from any potential obstacles you may continue the approach.

If you're flying out and on the leg from "A" to "B" and all of a sudden you look back out the window and the airport is gone in the haze and clouds, you need to go missed: You've lost the airport/runway environment, and can no longer judge your distance to stay in the "safe" airspace.

Similarly if you're in a high-wing aircraft and your turns at "B" and "C" briefly obscure the airport while you're turning you can still continue the approach - if you've any doubt where the airport is just pick up the wing like you would in a VFR pattern (and if the airport isn't there like it's supposed to be go missed!)

Regarding your bird scenario, that's an interesting one that I don't think is covered in any diagrams, but if a flock of birds causes you to maneuver in such a way that you lose contact with the airport (and you can't just pick up a wing and have it be right where you expected it to be) you're obviously going to have to abandon the approach and go missed. It's the equivalent of the airport disappearing in the haze on that A-to-B leg.

Honestly though, if a flock of birds shows up and hangs out in a way that requires you to start maneuvering around them while you're trying to shoot a circling approach in real IFR you may want to just go missed anyway (given the odds this probably won't cost you too many approaches).

In a real world situation with poor visibility, possibly precipitation, and likely a cloud ceiling really close to your altitude, do you really want to try to be maneuvering down low to avoid some stupid bird that couldn't even be bothered to call the tower?

Wouldn't you feel much better pointing the aircraft in a generally "upward" direction and following the nice friendly needle again for a little while?

I'm just starting my IFR training, but I think I'd feel better with that option :-)


Where can I find coordinates for Special Use Airspace (e.g. restricted areas) in the USA?

As Pondlife says, this answer tells you where to look: All special-use airspace is defined in JO 7400.10. Version C is current as of February 16 2021.


Was this a successful deployment of an MD-88 tail cone evacuation slide?

Considering that the slide was not deployed, it is definitely unsuccessful. The MD-80 series (also the DC-9 and boeing 717) had tail cone assemblies which could be jettisioned in case of an emergency.

When operated, the tailcone is expected to swing to the left of the fuselage due to to its own weight because of the way it was rigged.

The jettison cone is attached to the slide through a lanyard, which passes through two eyelets in the tail cone and is attached to a spring in the middle of the cone.
As the jettison mechanism is activated, the tail cone is released and because of the way it is rigged, turns 90$^\circ$ and moves to the left of the aircraft to keep it from interfering with the slide deployment.
As it falls, it pulls on the slide container via the slide lanyard, moving it so that it can inflate and delpoy, while the tail cone remains to one side of the aircraft.

You can see it in the images below:

All images taken from Accident Report IN-045/2004

The following image shows the undeployed slide (in an MD-81) from the inside along with the lanyard.

Image from aircrewbuzz.blogspot.in

The release can be made by three ways- there is an emergency handle on the aft bulkhead door, one at the end of the catwalk and another one in the exterior of the handle.

In this case, the tail cone has pulled the lanyard, but the slide has failed to delpoy. While I'm not sure why the cone is hanging, it appears that the lanyard has snagged somwhere, probably in the cam rotator.

Note: This would not be the first time the slide has failed to deploy/deployed unsuccesfully or has deployed inadvertently. Also, see this discussion on the MD-88 tailcone jettison and slide deployment mechanism here.


why is rhumb line bearing for this question 270 as the answer?

The only movement in the east-west direction is your 2nd leg, moving west. Therefore, from the starting point G to the ending point K, the bearing is west, 270 degrees. The answer 090 would describe the course from K to G to close the path.
K--->090--->G
^           |
|           V
J<---270<---H

All the legs are the same length, and the north/south aren't drawn to the same scale as the east/west, but it's just a square.  270 from H to J, so 090 from K to G.  And thus 270 from G to K.


In addition to repaints, aircraft are also periodically washed and treated to maintain the paint quality and reduce the build up of dust/grime/salt and other particulates.

There are automated systems installed at some airports to clean airplanes as they taxi over these areas. Think of it as a drive through car wash, but for airplanes.

The very first applications of these were actually for the US Navy because they have a requirement to wash aircraft due to their proximity to seawater. A company called tammermatic developed a system for the navy to clean airplanes directly on the field using a set of powerful jets. Images from the tammermatic website

Then there is the Skywash system (PDF brochure), developed by PMW (a company that makes concrete pumps) to wash aircraft automatically. It was first used by Lufthansa in 1997 (image cc: ARNE DEDERT / AFP):


What should a pilot do upon reaching a Missed Approach Fix when holding instructions are not given?

The clip doesn't show it, but you must be looking at an RNAV approach chart for 20R. The ILS charts for 20R show the holding pattern in the plates. Since RNAV states "Radar Required" if the pilot doesn't get further instructions he/she should immediately ask for them.


How is rotor pitch best managed in helicopter autorotation?

No, that is not how it is done: minimal collective blade pitch is not negative. The procedure is to lower collective immediately to the full down stop to minimise blade drag, upon which the helicopter will start to descend. The air upflow tilts the local lift vector forwards. Indeed, just like in a glider.

The bit that is not intuitively clear for fixed wingers is the reference frame of the airflow, which is the local blade velocity.

The inner bit of the rotor blade has a lower rotational speed than the tip. The up flow has a relatively larger influence on the lift vector tilt here, and  upflow through the rotor drives the inner part of the rotor blade forward, while the outer part still experiences decelerating torques. From Leishman:


Are there aircraft that fly without fuel or electricity?

Yes, there are so many sources of energy you can use.

In the simplest form we have Buoyancy, Human power, Fly wheel, Rubber band.

More complicated mechanisms include compressed air, steam, hydrogen peroxide, which you can either use directly as a rocket/jet, or drive a piston engine or turbine to further drive a fan or a prop.....

Or, if you prefer, you can never go wrong with nukes

(Although one could argue nuclear and peroxide(and other mono-propellants) are fuels)

Here I'll just present my favorite out of all the possibilities.

Picture credit: TIHOOD


Is it possible to give an endorsement via text message or email?

Easy, peasy. Fill out a label/sticker with the endorsement printed on it. Then, all you have to do is sign it and place your CFI number on it. You can then either scan it or take a photo of it. Your student can upload the scanned document or photo into an electronic logbook. If they do not have an electronic logbook, they can print out the endorsement at the FBO to put into their paper logbook. When you and the student are together again, you can place the actual label/sticker in their logbook. Alternatively, you can use regular paper. Then you can cut the endorsement into a manageable size and tape it into the logbook. Also, if you and your student use the same software for your electronic logbooks, many have a function to sign endorsements electronically even at a distance (through the internet).


Why are winches not used for towing commercial planes up?

If you ever get the chance, do try a winch start in a glider. It is, to say the least, an interesting experience. I do not believe it would be accepted by the general public.

So, that is one more reason, it would scare the paying passengers.


What are the risks in landing on a beach vs. shallow waters?

Having done my primary training essentially over beaches I'm pretty well-versed in the theory (but thankfully not the practice) of landing on beaches.

Given the possible choices offered at your typical beach, the order of preference for landing areas is generally:

Pavement
People like to drive their cars to the beach. There's probably a road or parking lot nearby, and if it's empty enough that's where you want to land.
Dirt (not sand)
Some beaches have "sandy dirt" areas, usually with low grasses and the like on them. If the beach you're contemplating has such an area it's probably your second-best choice as it will be the firmest ground and closest to landing on a grass strip. (Beware of bumps and rocks!)
Wet Sand
The sand between the high-water mark and the low-water mark on the beach tends to be fairly compacted, so it can make a decent landing area. It will probably be softer than dirt/grass, but give it your best soft-field technique and you can probably set the plane down without damaging it.
Properly executed you can put the plane down without doing any substantial damage, and if it's an actual emergency you're unlikely to get in any trouble.

Dry Sand
Fluffy dry sand is a decidedly soft field situation - soft enough that in a nosewheel aircraft there's a very good chance that no matter how careful you are or how good your soft-field technique is you'll lose one or more of your landing gear - but at least you're on dry land.
The recent incident in Florida is an example of this: the aircraft's nose gear was sheared off as you can see below, but the pilot and passenger walked away (sadly some bystanders on the ground were injured, and one was killed).

Water
Unless your plane is on floats water is basically the landing of last resort - particularly for fixed-gear aircraft. The forces involved in putting your wheels into even 6-10 inches of water are pretty substantial, and there is a real chance of tearing off the gear or losing control of the aircraft in the last few seconds.
Even if the actual landing is uneventful you will be left to contend with being in the water while evacuating the aircraft which adds complexity to an already difficult situation (and if you're far enough out that the depth of the water is measured in feet you're going to have to swim back to shore once everyone is out of the aircraft).

  "Ditching" an aircraft in the water is a subject worth looking into on its own. Smarter people than I have written and spoken volumes about it, but as Skip Miller pointed out we don't really have a lot of hard data.


Why do the missiles on an F-16 point slightly down?

If you take a look at the picture again, you'll see that the missiles are in fact lined up quite nicely with the nose of the plane. The missiles are not pointed down, they are pointed forward. The wings and engine (and the entire back two-thirds of the plane) are pointed up, which provides the lift to keep the plane in the air during normal flight. You can see pretty well the alignment in reference to the horizon in this picture (found by @jay-carr):

Just to cut off the potential comments about how planes generate lift, reference is here.


Can ramjets reach higher thermal efficiencies than gas turbines?

The Carnot condition notwithstanding, whether a ramjet actually operates at a higher "hot end" temperature than a turbojet is questionable, as well as whether a comparable percentage of thermal energy in the exhaust stream is converted to kinetic energy.
Further, just because there's no turbine, doesn't mean there's nothing in the hot part of the engine that can melt -- combustion chamber walls are made of real material, as is the flameholder, and due to cost of exotic metals, likely aren't as heat resistant as first stage turbine blades.  Even a very simple, low-powered ramjet (see YouTube) can operate at a temperature that makes the hot section glow from heat; one capable of propelling a high speed aircraft will presumably run even hotter, requiring tradeoffs in efficiency to prevent thermal damage.


When inverted, cut power. As speed bleeds off, gradually move stick forward keep your flight level, the nose will come up quite a bit over the horizon. It is important not to start sinking here as that will prevent the speed coming down low enough. When the stick hits the forward stop, kick in full rudder either way.

Enjoy!


Will a stalled aircraft fall down like a brick? Or how steep does the Lift-AoA curve fall off after stall?

You make some valid observations: not all lift disappears after the stall, and at the event of stall there is a downward acceleration that may or may not be perceived.

Let's start with what happens after the stall. Measurements on airfoils have been taken over 180°, and they show that after the stall, lift drops back until flat plate lift is achieved at the same angle of attack. Increase AoA further, and lift increases again. An example for a relatively thin airfoil from this document:

Pull the aircraft back far enough to 45°, and the $C_L$ is even higher than when it stalled! Of course, the drag will be huge compared to normal operating circumstances, and any fixed wing other than a military jet fighter or a VTOL won't have enough power installed to fly at such angles of attack.
Isn't there a perceived loss of body weight during the acceleration to stall. Yes there is, but it does not last long, is not necessarily very powerful, and could be referenced to other factors than stall, such as turbulence. Once the $C_L$ - $\alpha$ curve hits the trough at 15°, the acceleration stops and weight perception returns to normal. And it's sensory perception, the body only really understands what is happening if all sensory organs are aligned (vision, motion, sound), and can only react in a composed manner if it anticipated the cues and is trained in how to respond. Otherwise we just fight or flee.

You mention the case of AF447. It was in a fully developed stall and descending with on average 10,000 ft/min, but the onset to stall was different. It was  very gradual, and it was a high speed high altitude stall: there simply is not enough air up there to provide enough lift for the weight of an airliner. It can stall at AoA of zero, then start to fall, as a result of which the AoA changes but the pitch attitude of the aircraft does not, and your body is still aligned with gravity in a dark cockpit where the horizon cannot be seen. No physical cues on what is happening whatsoever!


Why are jet fuel prices very similar in North America and Europe, yet automotive fuel prices are very different?

Jet fuel for international commercial aviation is effectively not taxed due to an agreement between ICAO member states. (See here ICAO PDF  ). Therefore the prices closely track to cost of production and distribution. These are similar worldwide. Differences exists due to local taxes on companies, difference in costs of transport, effects of competition on price etc, but these effects are limited.

Automotive fuel is taxed. I am originally from the Netherlands, where we have one of the highest taxes in the world when it comes to fuel taxes. Petrol costs at the moment approximately 1.66 Euro/litre, of which 68.84% is taxes.

In the US, the average total tax (federal plus local) is \$0.4818 on a gallon of gas (equivalent to \$0.1289 per litre).

So the difference in tax makes most of the difference in automotive fuel prices.

Sources: wikipedia


Is flight training on Russian planes performed in Russian?

Kind of unclear, but this would be dependent upon the country in which the flight training is taking place. If the training is taking place in Russia, most likely the instructor would speak to the student in Russian. If in the United States, the instructor would speak to the student in English.  As for ATC  transmissions, the only time the flight crew would be required to speak in English would be on an IFR flight plan. Any other time, they would speak their native language on the radio.


Do ultralights need to have EPA-compliant engines in the USA and Canada?

No such thing as EPA compliance on General Aviation engines or ultralight engines for that matter.  You buy a piston engine from Continental or Lycoming, it has no pollution controls of any kind. It's like it's 1960.  There just aren't enough of them to make any real impact, so they get a pass.

Pretty much anything goes for a Part 103 Ultralight in the US or what is called a "Basic Ultralight" in Canada.  Whatever suits you.


Why is the landing gear lever not set to OFF on the ground?

Because there's no advantage to doing so (since the pumps will soon be off anyway, as the question notes), and this would create the risk that the pilot may overshoot the Off position to the Up position, which could, on a bad day, lead to an inadvertent gear retraction and major damage. The over-center locks are good, but do you really want to bet big bucks that the combination of 3,000 psi + a bad bump in the pavement will never produce an illustration of Murphy's Law?
Okay, there is one other safety to prevent overshooting, but that solenoid can fail, and if it does, watch out! There is simply zero need for this.
Also, depending on the plumbing, you might remove hydraulic pressure from the nosewheel steering by doing this (though I'd have to check the diagram to be sure).


What should you do when the pattern is crowded?

As PIC if you don't feel comfortable entering congested airspace at a beehive airport, dont enter it.  It's that simple.  Divert to another airfield and attempt to return to the original airfield when the congestion abates.

If you anticipate high density traffic at an untowered airport, you should let other pilots know your intentions on the CTAF well in advance, generally at least 10NM from the field.  Closely monitor other CTAF pilot reports and start building a mental picture of traffic reporting their positions in the pattern, entering the pattern, or leaving it and begin to adjust your entry speed and position for appropriate separation and traffic flow.  Most other pilots will work with you on this and make changes to their traffic pattern to accommodate you as well.

If you have a fuel emergency or any other emergency for that matter and no other alternative is available, declare an emergency on the CTAF, indicate your position, altitude and intentions.  All other traffic in the pattern, by federal law, MUST give way for you


How can I calculate the cabin pressure following a decompression?

You should read through this paper it outlines a lot of great info on calculating valve size for cabin outflow valves in pressurized aircraft it also addresses your second point (to an extent) on the flow rate of compression systems. The issue you will encounter is that the calculations will only hold for a controlled situation i.e. a situation where you have precise control over the valve (hole) size and can account for small leaks.

In the most generic terms you can find the calculation for flow rate through a hole in a pressure vessel here.

Your specific example is going to be a bit more complex since after a cabin pressure failure the plane will begin a descent rapidly to 10,000ft. so your exterior pressure will be rising as your interior pressure drops (you will need to factor that in to make the above solution a complete result). You also need to consider the airflow over the airframe its self since you are talking about a situation where the aircraft is in flight you have some fluid mechanics to play in as well.

Its called explosive decompression for a reason, its going to happen very very fast.


May a Recreational Pilot demonstrate her/his own plane to a prospective buyer?

It looks like a recreational pilot can demo their own aircraft, because the FAA considers "salesperson" to be a profession or job in the lay sense that you mentioned.
This is from the Federal Register:

The FAA maintains that, for sales demonstrations that are not
conducted by an aircraft salesperson, a sport pilot or a recreational
pilot can conduct this activity. Therefore, to ensure that
recreational pilots have at least the same privileges as sport pilots,
the FAA is revising § 61.101(d)(12) to allow a recreational pilot to
conduct sales demonstration flights as long as the pilot is not acting
as an aircraft salesperson.

The original wording of 61.101(d)(12) was:

To demonstrate that aircraft in flight to a prospective buyer

The current wording you quoted is:

to demonstrate that aircraft in flight as an aircraft salesperson to a
prospective buyer

In other words, they added "as an aircraft salesperson" to clarify that the restriction only applies to salespeople, not to all recreational pilots.
That means the question you quoted is apparently wrong. As to why it's wrong, I have no idea. The FAA doesn't actually publish its test question banks so many "FAA questions" out there aren't official at all.


Is ADS-B intended to replace other traffic management systems?

For a short introduction on what ADS-B is and why it is called dependent see this answer.

ADS-B is a surveillance technology whereby the aircraft broadcasts information about its identity, position, altitude and velocity of the aircraft to any interesting party. The position and velocity information is derived from GNSS (GPS).

TCAS

ADS-B is not intended to replace TCAS, although in the future it will augment TCAS. The TCAS algorithm currently only uses distance and altitude to calculate whether there is a conflict and to determine the best conflict resolution strategy. With the more accurate ADS-B position available to the system as well, the number of TCAS interrogation can be reduced (the surveillance radio frequencies are getting congested in some areas) and the performance of TCAS can be improved. A new standard for this hybrid approach was published in 2013.

It may also be possible to have a passive TCAS-like system that does not require active interrogation but is purely depending on ADS-B. Currently a technical standard for a new Airborne Collision Avoidance System (ACAS, the generic name for TCAS) is being developed in a joint RTCA / EUROCAE committee (RTCA SC-147 / EUROCAE WG-75), which will take advantage of more data offered by ADS-B. This new standard will eventually replace TCAS II.

A 'TCAS light' for small aviation has also been developed based on ADS-B. It is called  Traffic Situation Awareness with Alerts (TSAA), a standard that was published last year. Within the next couple of years we will see manufacturers start offering products based on this standard.

ATC

The purpose of ADS-B is neither to replace ground based ATC. But it will change the way ATC is done. ADS-B IN will improve the situation awareness of pilots; they will have a display of accurate positions of other aircraft. New procedures will allow pilots to maintain visual separation to other aircraft in marginal Visual Meteorological Conditions (VMC), where they currently would often lose sight of other traffic. A more advanced usage of ADS-B will be flight deck based interval management (FIM) where ATC will be able to instruct aircraft to 'follow that plane XX seconds behind for landing on runway YY'. A first technical standard for FIM is being worked on, it is intended to be published before the end of this year.

ADS-B is neither a replacement for all radars, although it will allow the number of radars to be reduced. For remote areas that currently do not have radar coverage because of the associated high costs, ADS-B will be a cost effective alternative. Over the oceans, satellite ADS-B receivers will be able to provide surveillance, changing the way ATC is performed over the high seas.

GNSS

Given the examples above, it is easy to understand the requirements on the reliability of ADS-B are substantial. Not only must the system be able to deliver accurate position data, it must be able to deliver that data with high integrity. That means, the probability that the system transmits inaccurate position data, even when there is a failure in the system, must be extremely small. To achieve this, a positioning systems must be able to do internal cross checks to detect failures and not depend on possible erroneous inputs from humans. GPS can meet the position source requirements using Receiver Autonomous Integrity Monitoring (RAIM).

The ADS-B technical specifications have all been written in such a way that they do not explicitly require GNSS to be the position source, but at the moment it is the only system that meets the requirement effectively. Most certification documents are written with the assumption that a GNSS will be used to provide position data. Theoretically one could put another system forward, but the costs of certifying that would be very high.


Why was my flight cancelled due to bad weather while other flights were not?

In general, flights get cancelled when arriving flights are delayed or themselves cancelled. Your flight needs three critical things to depart on time, or at all:

an airplane,
flight + cabin crew, and
weather that meets requirements

Aircraft may not arrive due to weather diversions (couldn't land with fuel on hand, etc). If there's no airplane, your flight obviously can't depart. Same goes for bad weather at your departure airport - if it's too bad, you can't go. If the weather at your destination is bad, the flight may also be delayed because the airport can't handle as many aircraft as normal. That's fairly straightforward. Where it gets most complicated is the crew.

Crew have what are referred to as "duty and rest requirements" (at least in the US; other jurisdictions have similar rules, possibly with a different name). A flight crew is "on duty" when they're first scheduled to fly, whether the flight happens or not, and the number of "duty hours" they can have on a given day are limited. The FAA last revised these rules in 2011, as far as I know, but I'm not an airline pilot. With the 2011 rules, "Flight Duty Period limits under the new rules range from nine to 14 hours". These rules exist to prevent fatigue, a major cause of aviation accidents.

What this means is that if weather delays cause crews to overfly their limits, they may be unable to operate the outbound flight. With your example of Frankfurt, there is weather causing delays to arriving flights.

For example...

If a hypothetical crew with a 10 hour duty limit was scheduled to fly, say, three LHR-FRA round trips (call it 3 hours of flight duty time each round trip; this may not be a valid example), but were delayed on their third FRA arrival by 2 hours, they would exceed their duty limits by 1 hour on the return flight (1.5 * 2 + 1.5 * 2 + 1.5 + 2 = 9.5 + 1.5 = 11 > 10). As a result, they would not legally be able to depart.

Normally, airlines plan for this with "reserve" crews that are on call to fill in for missing, sick, overflown, or otherwise unavailable crews so that flights are not seriously delayed. When a huge storm hits, this falls apart as there are not enough reserve crews to operate all the flights, and the situation snowballs out of control.

Our hypothetical crew would be replaced by reserve pilots (and cabin crew) if they were available, and the flight might be delayed by more than the 2-hour flight delay they experienced. If not, the flight would be canceled.