Does auto pilot take into consideration the altitude, speed, and the difference in heading change, to calculate the degree of bank?

If your talking about standard rate turns, those are not really practical in large commuter aircraft. As true airspeed increases the maximum turn rate decreases when the bank angle is limited to a comfortable level of less than 30 degrees of bank. So please make this question more specific, which airplane category are you talking about?

Usually the autopilot uses the difference between the target heading and the current heading to generate a bank angle target, often just proportional by a linear factor but limited to, e.g. 25 degrees of bank or the minimum of a 30 degree bank turn and a standard rate turn bank angle or even manually selected like in the Boeing aircraft.
The autopilot then calculates the difference between the target bank angle and the actual bank angle and generates a roll rate target. Based on the roll rate target and current roll rate the autopilot computes a roll acceleration target and finally an aileron deflection target, which could, for example, just be a factor times the roll rate deviation.

The computation from the deviation of any of these parameters to the next lower level control loop target can consider the true airspeed and altitude, yes. But this can't be said for all types of autopilots that ever existed and is too broad of a question.

For certification of an autopilot system it has to be demonstrated that the autopilot remains within a safe enveloped, as specified in the requirements. This could limit the roll acceleration, roll rate, maximum bank angle or demand a response within a certain time frame or a maximum deviation for any of these values, transient allowed overshoots, etc. Since the autopilot has to work throughout the flight envelope the parameters used in the computation of the bank angle, roll rate, roll acceleration, aileron deflection, etc. may require a look-up table for each airspeed and altitude to ensure a stable and safe operation.
This can differ between aircraft types, e.g. a large passenger aircraft should fly less aggressive roll maneuvers because the people sitting on the outside far away from the center are being subjected to major g-forces as the aircraft rolls, which is uncomfortable and potentially hazardous.


How to calculate required thrust for take-off knowing gross weight and L/D?

http://www.dept.aoe.vt.edu/~lutze/AOE3104/takeoff&landing.pdf

This source has been really helpful for me in calculating takeoff time and takeoff distance. In this method, the author uses thrust as an input to calculate takeoff distance, but obviously you could re-arrange the equations to calculate for thrust if you knew the other variables. You will likely need to know the static thrust (zero speed thrust) of your engine and then can calculate for thrust required at takeoff. I would recommend putting the equations into an excel spreadsheet where you can then play with all the inputs until you reach a desired result. Hope this helps!


if temperature is increased but the volume contained in a area, will an air balloon lift?

I case of an hot air balloon, the volume of the balloon remains unchanged when the air is heated. But because the heated air expands, part of it escapes from the balloon since it is not closed (the bottom is open). Therefore the weight of the air inside the balloon is reduced. The hot air in the balloon has a lower density that the cool air around it. Therefore the balloon lifts.

Would a closed balloon of unstretchable fabric be used, then the pressure in the balloon would rise but the volume of the balloon would remain unchanged. Therefore the density of the air inside the balloon and the buoyancy would remain the same and the balloon would not lift off.


From lowest to highest wing loading:

Climb: if a fixed wing plane and the nose is pointing up, some of the vertical force must be generated by the thrust.
Cruise: the lift must only compensate for the weight.
Inducing a turn: the rolling velocity has very little effect on wing loading.
Take-off: a slight positive g-loading during the nose-up motion.
Sustained turn: up to the maximum design load factor. 2.5g for passenger aeroplanes, up to 9g for fighter jets, with a proportionately greater wing loading that that in cruise.


what reference of airfoil is used to define lift and drag?

This is a basic question, and I give you the answer from the initial pages of a aerodynamic learning textbook.

The  is presented in next figure:

Where:

L: lift: component of R (resultant force) perpendicular to air stream,
D: drag: component of R parallel with the air stream,
N: Normal Force: component of R perpendicular to chord,
A: Axial Force: component of R parallel with chord,

For further information you can refer to Anderson's Aerodynamic book.


Looks very much like a de Havilland DH.82 Tiger Moth.

This webpage lists all Tiger Moths used by the RAAF.


How does an airport catch up when it is behind on traffic?

Most airports aren't at 100% capacity any of the time: they simply fit in a few extra flights for a couple of hours until they're back on track, causing relatively little delay.
Even those who are at 100% capacity sometimes, aren't usually at 100% capacity 24/7. They can recover by delaying everyone a little for a few hours, with the delay slowly reducing as the airport gets quieter

With a very busy airport (Heathrow is often quoted as an example), however, it's possible that the airport is at/near 100% capacity for long periods. Heathrow runs at nearly 100% capacity (roughly 98%), and much of the "quiet" period is actually at the very start of the day which doesn't leave much slack.

However, there's some scope for "absorbing" flight delays: at Heathrow, most aircraft will sit in a "hold" stack for a while before landing. Aircraft join this stack as they arrive and wait their turn to land. If one plane is a little late, another will simply take its place in the queue and everyone jumps "up" one space until the delayed flight. As long as there are aircraft in the stack, short delays or aircraft arriving early don't really make things too chaotic - there are still 60 aircraft landing in the next hour, it doesn't really matter what order they land in.

However if there's a bigger problem such as ice, which means the overall capacity is reduced, flights must be cancelled as they simply cannot all fit in. In this case the airport will typically reduce capacity across the board and allow the airlines to choose which flights to cancel. In the case of Heathrow, this will usually be the relatively local, high-frequency routes: eg the once-a-day flight to Sydney, Australia will still fly, but one of the once-per-hour Glasgow flights will be cancelled. For the most part the number of cancelled flights is down to the airport/ATC, but the specific flights cancelled are up to the airlines.


Can ATC separate IFR traffic in class A airspace from VFR traffic in class E?

Keep in mind that ATC only separates IFR traffic from other IFR traffic. So they would not provide separation from any VFR traffic no matter what the airspace (with the exception of Class B).

AIM 4−4−11. IFR Separation Standards

  b. Separation will be provided between all aircraft operating on IFR
  flight plans except during that part of the flight (outside Class B
  airspace or a TRSA) being conducted on a VFR−on−top/VFR conditions
  clearance. Under these conditions, ATC may issue traffic advisories,
  but it is the sole responsibility of the pilot to be vigilant so as to
  see and avoid other aircraft.


How does aviation deal with satellite and Moon laser ranging, and other scientific lasers in the sky?

Is there a NOTAM or a temporary flight restriction associated with laser ranging activity?

Apparently yes:

The lasers on the telescopes are in the range of 15-40 watts. The FAA calls a no-fly zone over the area when a laser is in use, and two people have to stand around outside in the freezing temperatures and watch for airplanes. Each of them has a kill switch to turn off the laser in case an airplane comes near. [...]
To clarify, the FAA does not have a no-fly zone, but instead issues a “Notice to Airmen” or NOTAM about the laser operations.

I also worked on an Adaptive Optics project and it was given for granted that NOTAMs would be issued by the people in charge of the experiments.
Example of NOTAM:

FDC 0/7651 ZDC .. SPECIAL NOTICE .. LASER OPERATIONS EFFECTIVE
1005010001 UTC UNTIL 1112312359 UTC. SCIENTIFIC AND RESEARCH LASER
OPERATIONS WILL BE CONDUCTED AT THE NASA GODDARD SPACE CENTER IN
GREENBELT, MARYLAND, LOCATED AT 390113N/764939W. THE SYSTEM IS
INTERMITTENT, WITH POSSIBLE OPERATIONS HAPPENING 24 HOURS A DAY, 7
DAYS A WEEK. THE LASER BEAM MAY BE INJURIOUS TO PILOTS/AIRCREWS AND
PASSENGERS EYES FOR A DISTANCE OF 98,000 FEET ABOVE GROUND LEVEL.
HOWEVER, THIS SYSTEM USES A LASER HAZARD REDUCTION SYSTEM RADAR THAT
IS SLAVED TO THE TELESCOPE MOUNT TO ENSURE THE LASER IS DEACTIVATED IN
THE EVENT AN AIRCRAFT APPROACHES. THE AREA WILL ALSO BE MONITORED BY
OBSERVERS AND THE LASER BEAM WILL BE TERMINATED IF NONPARTICIPATING
AIRCRAFT ARE DETECTED. LASER IRRADIANCE LEVELS WILL NOT EXCEED THE
MAXIMUM PERMISSIBLE EXPOSURE LEVELS WITHIN THE LASER FREE, CRITICAL
FLIGHT, AND SENSITIVE FLIGHT ZONES. OTHER VISUAL EFFECTS, E.G.,
FLASHBLINDNESS, AFTER IMAGE, GLARE, AND DISTRACTION MAY OCCUR AT
GREATER DISTANCES. THE POTOMAC TRACON /PCT/ PHONE NUMBER 540-349-7541
IS THE FAA COORDINATION FACILITY.

How dangerous is a laser beam for passengers and crew, and for the aircraft?

For the aircraft (meaning the hull) it is no danger, 40 watts of unfocused power (astronomers do not need laser beams in the sky as focused as the beams in an optics lab) do not affect the hull.
For the eyes of pilots and passengers it can instead be extremely dangerous, see Why is laser illumation of a cockpit an emergency?


Which FAA regulations apply to the Stratolaunch?

That would be under Title 14 CFR, Chapters 400-460.

A lot of this stuff really hasn't been finalized yet and these vehicles are considered only experimental and regulated similar to homebuilt aircraft.  Passengers are required to sign waivers advising them of their risk and that they understand this and hold the organization indemniable to any and all liabilities involved with using this system.


Can a helicopter fly VFR at night in India?

In short, yes, a helicopter can fly at night, in the US.  Special VFR requires that the aircraft and pilot be instrument capable, but that requirement is not applicable to helicopters.  VFR weather minima are different for helicopters than airplanes.


Why do semitailless swept-winged aircraft, but not delta-winged aircraft, suffer from (primarily) pitch oscillations at high mach?

The function of a "tail" in this case is pitch stability.  Therefore, all stable aircraft must have "tails".  Aerodynamically, the rear portion of the delta is its tail.  Removing it should have predictable consequences, even in the subsonic realm.
Transonically, with shock waves dancing on the wings and a moving center of pressure, pitch stability is critical.  This is also true in slow flight, where a shifting center of pressure can overwhelm weaker pitch stability.
Subsonically, the swept tailless design can be helped by "washing out" (lowering the AOA of) the wing tips or by adding slats, which helps control movement of the center of pressure at higher angles of attack.  As Dunne ingeniously realized over a century ago, this design made for a stable aircraft.  Indeed, a swept wing aircraft with insufficient tail area could be helped with stronger slats!  (If the wing tips can handle the extra load).
Transonic and supersonic flight is another issue.  The notion of "taillessness" was a blind alley in aviation design, a mistake not to be repeated.


It's complicated ;)

There are two types of stability; dynamic and static.

If an aircraft is disturbed by, say, a gust of wind, it will deviate from its attitude but then will immediately and without control inputs return to its original attitude.  This is positive static stability.  If it remains in the disturbed attitude unless corrected, it has neutral static stability.  If it continues to deviate, it has negative static stability.

If the aircraft returns to its original attitude, overshoots a bit, then corrects back, overshoots a little bit less and so on, eventually returning to its original attitude, then it has positive dynamic stability.  If these oscillations continue and do not "damp" down until the original attitude is regained, then it has neutral dynamic stability.  If the oscillations grow increasingly large, then it has negative dynamic stability.

For helicopters, I will ignore those with autopilots, hydraulic controls and stability augmentation systems.

Imagine hovering.  A gust of wind hits the helicopter.  The disk will "flap" away from the gust and the helicopter will move with the gust.  When the gust stops, the disk now experiences airflow from the opposite direction, since it is now moving sideways.  The disk will flap back the other way, returning to neutral but the fuselage acts as a pendulum hanging under the disk and its momentum will cause it to swing further out, tilting the disk more and causing the helicopter to move faster in the opposite direction to the gust than is required to return to the original attitude.  Eventually, the airflow now comes from the direction the helicopter is moving in so the disk flaps away, the fuselage swings too far and......  Unless corrected, it will continue to swing backwards and forwards, rolling, yawing and pitching.  It is statically stable (because it tends to return to the original attitude) but dynamically unstable since it continues to swing backwards and forwards from the original attitude.

In forward flight (and unless you want to know, I'll skip the details which include what direction the gust comes from, the tendency of the fuselage to weathercock and "blowback" since the details all about which way the disk flaps and which way the fuselage weathercocks and are a lot of words!), a helicopter is statically stable and dynamically stable in yaw and is statically stable and dynamically unstable in pitch and roll.

You can take your feet of the pedals and the aircraft will be stable in yaw.  You can take your hand off the collective (although you should never do this - if the engine quits, you need that lever down fast) and it will stay where it is, ignoring perhaps vibration making it eventually move up or down.

You cannot take your hand off the cyclic since this is the control which determines pitch and roll and corrects for dynamic instability on a constant basis.

On a light helicopter, you would be out of control within a second or two.  On a heavy, maybe three or four seconds.

In summary, a helicopter is statically stable and dynamically unstable in all three axes in hover and forward flight except yaw in forward flight where it is dynamically stable.


How do I calculate the impact of the winds aloft in this test question?

First of all, make sure you’re only doing the questions that will actually be on the test you’re taking. This specific question is only for the LSL question bank, so unless that’s what you need, forget it and move on.
In a balloon, you will be carried by the winds aloft. If the wind is from 100@8, then your track will be to 280@8.
First, use your protractor to draw a track line on a track of 280 from the point of departure. This shows your balloon’s track over the ground.
Next, multiply 8 by the (decimal) number of hours you will be in the air, and then use your scale to mark that distance along the track line. That’s how far your balloon will have traveled at the specified time.
No need for an E6B here.


What changes do narrow-body airliners undergo to serve (relatively) long routes?

The 737 ER (Extended Range) differs from the rest of its family by having an extra fuel tank extending its effective range.

Legally speaking (for US registered aircraft) you don't need to carry life preservers for each passenger, if you are only flying over land routes. So if a plane is being used for say a JFK $\rightarrow$ Nashville route, they would not be required to carry life preservers; but if they decided to use the plane on an over water route, they would have to outfit it as such.

Inter-Country travel may also effect the outfitting of a plane, as various countries have different equipment requirements (although most are the same now). Long haul routes may very well translate to non domestic routes, which means the plane may need to be outfitted with extra equipment that is capable of working on foreign systems.

There may be some paperwork involved around certifications as well. For example the FCC does not require domestically operated aircraft (commercial and GA) to have radio station licenses; however, it's often required by many foreign entities. A domestic only plane may need to obtain one of these licenses before heading to is destination.

On a bit of a side note the pilot must also be familiar with the destinations' regulations and methods of operation. For example here is a nice briefing from the FAA on flying into China.


How is airbrake function performed on the Dassault Rafale?

The Dassault Rafale has no dedicated airbrakes. By having two means of pitch control, namely wing elevons and canards, in combination with relaxed stability and an advanced FCS, it can move both into extreme deflection angles without sacrificing pitch control. This site states:

  When landing, both canards and trailling-edge control surfaces can be
  used for braking, and Rafale may be able to use canards for braking
  even while in flight.

Also, having little load to carry helps. The display aircraft was most likely flying close to its minimum wing loading (which is just 276 kg/m²), and by cutting back thrust could employ its regular aerodynamic drag for braking.


How can I estimate the required T/O power for propeller aircraft?

You need takeoff speed (from the lift coefficient, wing surface and altitude) and the time in which you need to achieve it (before you run off the runway). That'll give you the needed acceleration ($a = \frac{\Delta v}{s}$)

From that you can know how much force the prop must generate ($F = ma$).

Add some margin to account for friction losses.


Most jetliners are equipped with "p-a-c-k-s" which stands for
  Pressurization Air Conditioning Kits".

The air conditioning (A/C) packs are usually located at the lower wing/fuselage root fairing beneath the fuselage.

source

On some jetliners (Douglas Aircraft DC-9 Series) the A/C packs are located in the tail, while other aircraft such as the McDonnell Douglas DC-10/MD-11 and Lockheed L-1011 are located in the front of the aircraft beneath the flight deck.

Nearly all jetliners have two packs, although larger aircraft such as the Boeing 747, Lockheed L-1011, and McDonnell-Douglas DC-10/MD-11 have three.


Do the compressors and turbine rotate at the same speed?

That's one badly-worded quote:

  Single spool jet engine. These are those jet engines who have one shaft inside them. The compressors and turbines rotate on a same shaft.

Correct. In a single-spool engine, all of the compressor and turbine stages rotate at the same speed because they're attached rigidly to the shaft.

  The speed of compressors and turbines decreases half way down the compressor stages, that is why they can’t match the local airflow.

No, the speed of the compressors and turbines doesn't change. It's the airflow that changes, and causes a mismatch.


What do compressor/turbine stages mean, and why we need a different number of stages?

For axial compressors (what you'd find in a typical turbofan), each stage is:

A rotating disk of blades
Stationary blades that follow.

They're called rotors and stators, respectively. So those two rows of blades are one stage.

The rotors increase the air's velocity, the stators turn this velocity into pressure, and repeat (see image below). The following stage would compress the air more, and so on, incrementally increasing the pressure.

Likewise but in reverse for the turbine stages (the fixed blades also come first).

Source: The Jet Engine (book)


Southwest corner of LAX has peculiar airplane parts, what is this area?

It is an aircraft fire simulator. They use it for training emergency response personnel and vehicles.

You can see them training on one in this YouTube video

Source: Leipzig Halle Airport


Are there specific regulations for airports near water bodies?

Yes, there are ICAO regulations requiring water rescue facilities. For example, from New marine rescue fleet launched at Auckland Airport:

  Airports which have a significant proportion of aircraft movements over water are required by the International Civil Aviation Organisation (ICAO) to provide a specialist rescue facility, capable of an effective response in a marine area around the airport. Marine rescue craft are required to be able to transport sufficient flotation equipment to an accident site to support the number of people carried in the largest aircraft.

You can find this regulation in the ICAO Aerodrome Standards document:

  Emergencies in difficult environments

  9.1.14 The plan shall include the ready availability of and coordination with appropriate specialist rescue services
  to be able to respond to emergencies where an aerodrome is located close to water and/or swampy areas and where a significant
  portion of approach or departure operations takes place over these areas.

  9.1.15 At those aerodromes located close to water and/or swampy areas, or difficult terrain, the aerodrome
  emergency plan shall include the establishment, testing and assessment at regular intervals of pre-determined response for the
  specialist rescue services.

Note that this does not necessarily require a navigation channel, as rescue operations can be primarily provided by hovercraft (as in Auckland).


In which direction should a turn-back be made after an engine failure on a multi engined airplane after take off?

That  depends on a lot of factors. Are you declaring an emergency? What altitude are you at what speed are you at when this happens etc?   What kind of aircraft are you flying? Does it have enough power to continue to climb on one engine? Some trainers do not.

For a typical airliner, loss of a single engine is not a big deal. The pilot will simply declare an emergency and get vectors from controllers as to where to go land again. Most airliners have plenty of power with one engine out and they don't have to worry about that. Smaller twin engined GA aircraft are a different story and may not be able to achieve a positive rate of climb on one engine, especially with the gear and flaps extended just after liftoff.  At low altitudes where this performance factor may be the case for the specific airplane you are flying, you may have to execute a forced landing in a clearing either directly ahead or off to your side, as a 180 deg turn to the airfield would be suicide.

As to maneuvering once an engine is lost, there is no requirement for this, save a pre-determined VFR traffic patterns for the departure airport.

If the engine out is an emergency and you cannot comply with either a controller's instructions or uncontrolled procedures, you are authorized as PIC to disregard any regulation as required to deal with the emergency.  This means any kind of maneuvering you feel will safely bring the aircraft back to the ground is acceptable.

I've read a lot of posts and comments amongst pilots about not turning into a dead engine on a twin; this is nonsense with one caveat - you must have sufficient airspeed in order to do this.  It depends on the aircraft in question but a good rule of thumb is that if you are at or above Vyse you can GENTLY turn into a dead engine.  The threat comes in attempting to turn into the dead engine at or near Vmc, minimum controllable airspeed on a single engine, where it may not be possible to arrest the turn due to thrust asymmetry.


Why did flying boats in the '30s and '40s have a longer range than land based aircraft?

Since fuel volume in aircraft is a large factor in range, and the volume of an aircraft increases faster than the linear size, larger aircraft have a big advantage for range. In the 1930s, the biggest hurdle for large land-based aircraft was infrastructure. Most airports in the 1930s were not very large, and many parts of the world did not have any at all. The common airliners at the time carried around 20 passengers.
Designing an aircraft that could land on the water allowed aircraft to get larger and have longer ranges without the need for large runways to be built to support them. Aircraft like the Sikorsky S-42 carried almost 40 passengers. It wasn't until at least the late 1930s that land based aircraft were able to reach this size, and after World War II the devolopment of infrastructure and aircraft technology made long-range land-based aircraft much more feasible.


If pitching moment creates drag, how can high and low moment airfoils have almost identical drag polars?

A high Cm airfoil does not mean it will be draggy by itself. However, it does mean that when combined with trim devices (e.g. tailplane, elevator, canard, elevon), the overall drag may be higher due to the trim drag component.

Since 25% MAC, about which pitching moments are generally cited, generally gives around 20% static margin for low speed aircraft, it's a rough first indication of how much trim would be required.


How or when can the 250 KIAS speed limit below 10,000ft be exceeded?

Not a local thing at all!

In Australia, it is extremely common to hear, especially for aircraft on departure. Listening to LiveATC, particularly Sydney International Approach/Departure (YSSY) you will quite often hear ATC give an aircraft permission to exceed 250KIAS below 10,000ft.

Qantas 123:
Approach, QFA123, with you passing 2,300, climbing 5,000..

Sydney Approach:
QFA123, Identified, Climb FL240, cancel speed restrictions below 10,000..

There are a number of reasons this is used. The first, I have already hinted to in the example radio call above.

Departures:
It is extremely common to hear ATC cancel speed restrictions on departing aircraft. This gives better separation for aircraft departing in the same direction. For example, one of the busiest sectors in the world is Sydney - Melbourne Australia. The common SID's out of Sydney for Melbourne are the DEENA4 WOL transition and the WOL1 Departure, depending on operational runway. As a large amount of aircraft use these departures, the further the lead aircraft can get on the SID prior to the trailing aircraft becoming airborne, the better.

Arrivals:
Again, using Sydney, they receive a large amount of Regional Turbo-Prop traffic (Dash 8-Q300/Q400, Saab 340B, BE350). You will commonly hear Approach cancel speed restrictions on these aircraft on decent so they can give them more space on the approach. They land reasonably slower than a B747/A380, so the more room, the better.

Another reason is simple. These guys are operating commercial operations, hence faster is better, especially on descent. So if there is no or low traffic in the TMA, ATC will commonly release the speed restriction on aircraft to accommodate the company operations.


Could airliners fetch data like AoA and speed from an INS?

An INS gives your speed & orientation in space, but without reference to what the airmass that you're flying in is doing.
The Pitot tube and AOA sensors give speed and pitch orientation in relation to the local airmass, only.
An indicated airspeed of 60 knots, measured by the Pitot tube, may correspond to a stationary aircraft pointed into 60 knots of wind, or an aircraft moving 30 knots over the ground into a 30 knot headwind, or 60 knots of groundspeed in still air, or some other case.  The wings fly (and stall) relative to the air, not the ground, so measurements of air data are vital.


Can I go into clouds if I got IFR clearance? (uncontrolled airport)

For typical uncontrolled airports which have instrument approaches, they are usually in Class G airspace from the surface to 700’ AGL.  In this airspace, yes, you can - at least from a regulatory perspective fly in IMC without ATC clearance, provided your remain clear of controlled airspace.

In order to fly a cleared IFR flight plan, you would have to depart into uncontrolled airspace prior to climbing into the Class E shelf above the airport.  Typically, IFR departure clearances from uncontrolled airports contain a time window in which you must be airborne and in contact with a regional departure control or ARTCC by eg “Clearance void 30 minutes from now”.  Basically, in doing so, ATC have given you a block of airspace which you have use of for a small time window in order to get airborne and join ARTCC on your cleared flight plan.  Once you have departed the uncontrolled airport on CTAF, you would immediately go over to your assigned departure control frequency and report in.  The controllers would thence take over and direct your flight.

A typical IFR clearance from a untowered airport would be something like as follows:

  Mooney Three One Two Seven Zulu, Atlanta Approach, Cleared IFR From Cartersville Victor Papa Charlie To Charleston Charlie Hotel Sierra Direct NELLO Then As Filed.  Climb And Maintain 5000, Expect 11000 Five Minutes After Departure, Atlanta Departure Control Is On 121.00, Squawk 2477. Clearance Void 30 Minutes From Now.

From the moment you copy the instructions and the controller acknowledges so with a “READBACK CORRECT”, you now have thirty minutes to get airborne, on a course direct to the NELLO fix and contact Atlanta Departure on 121.00 or the clearance becomes invalid and you must request a new clearance to do so.  If there are low clouds between you and the time you switch over to departure, so be it, you’re going into IMC.  Usually, though, it’s best once airborne and cleaned up, to immediately go over to departure control as quickly as you can.

Another example of IFR flight in Class G is flying an instrument approach into an uncontrolled airport.  Once you descend below the Class E shelf, the controller hands you off to CTAF and you continue on in uncontrolled airspace.  If you’re flying an ILS approach down to minimums, that may well be another 400-500 ft descending uncontrolled in IMC before you either break out and land or go missed, thence rejoin center to report a missed approach.


The following is a list of deadly turbulence accidents on jet airliners since 1980.
Excluded are accidents involving jet airliners designed or built in the former Soviet Union.
For a more complete list see aviation-safety.net.

10 May 1980, Indian Airlines B737-200, near Rampur Hat/India:
The aircraft experienced severe en route turbulence. 2 of the 132 passengers were killed.
7 October 1981, NLM CityHopper F28-4000, Moerdijk/Netherlands:
Shortly after takeoff, the aircraft entered an area of severe thunderstorm activity. The aircraft apparently had a catastrophic in flight structural failure due to severe turbulence because it was seen to emerge from the clouds with one of its wings broken away. All 4 crew members and 13 passengers were killed.
16 August 1982, China Airlines B747, near Hong Kong:
The aircraft encountered severe in flight turbulence. 2 (out of 292) passengers not wearing seatbelts were killed.
3 October 1990, Eastern Air Lines Flight 791, DC9-31, Florida/USA:
The aircraft clear air turbulence at 31,000 feet (9450 m). 1 injured passenger died 3 weeks later.
5 September 1996, Air France B747-400, near Ouagadougou/Burkina Faso:
Severe turbulence associated with a weather front seriously injured 3 of the 206 passengers. 1 of the 3 passengers later died of injuries caused by an in flight entertainment screen.
28 December 1997, United Airlines Flight 826, B747-100, over Pacific Ocean near Japan:
The aircraft encountered severe turbulence during cruise about 2 hours after departing Japan. 1 of the 346 passengers was killed and 3 crew members sustained serious injuries.


How can I calculate a gradient using a Jeppesen Student Flight Computer?

It works the same way as with the CRP-5. If for example the ground distance and height above ground level is given, then one aligns the ground distance on the inner scale (the B scale) with the height above ground level on the outer scale (A scale). Then look up the number 10 or 10 mark on the inner scale (the CRP-5 has an additional red arrow for this mark), and read the gradient in percentage on the outer scale.


Yes, both are stalled.

I guess a nit-pick is on "what is stalled"? I adopt that you are at or beyond the point that an increase in AOA results in an increase in lift (critical AOA). That's the top of the blue curve in the plot below.

Also, a stalled wing does not mean every point on the wing has unattached flow. It means the wing is operating at an AOA where an increase in AOA results in a decrease in lift.

At low angles of attack (AOA) planes are naturally stable in roll. The downgoing wing sees a higher AOA which results in more lift, and a restoring force. The upgoing wings sees a lower AOA, and less lift, so it is stabilizing too.

At a high AOA, though, you are operating on the backside of the wing lift diagram. In the picture below, this would be at and beyond 20 degrees AOA.

Now, the upgoing wing sees more lift, which leads to positively reinforcing going up. Same but opposite on the downgoing. It sees less lift.

Also, the red line shows drag. That downgoing wing (on inside of the spin) sees a great increase in drag, which will lead to a yaw towards that wing, i.e., pro-spin.

So to get in the situation where a roll/yaw movement is positively reinforcing, you need to be in stalled AOA. You might start with just one wing, you'll get to both.

JMHO!

EDIT

Here’s a NASA video of a wing with tufts when it is both on the inside of the spin and outside. Stalled in both (but different airflow).


Can you use a home built helicopter for solo hours?

I assume that this is for a Private Pilot - Helicopter license. I also assume you mean something like larger kit aircraft, not ultra-light helicopters like the Mosquito.

You can do this, but there are other conditions that must be met:

The aircraft must have completed it's flight test phase (this is usually the first 25-40 hours of operation)
The CFI must be willing to provide instruction in the aircraft. It will be difficult because either the CFI is not familiar with the aircraft or insurance won't cover them, some just won't fly homebuilts.
Your aircraft insurance must allow primary flight training in the aircraft (not many do)
The aircraft must meet requirements such has having a radio, transponder, etc for being able to operate in required airspaces.

The big ones will be finding a CFI willing to do this, and getting insurance to cover you. The insurance alone may outweigh the cost of renting a certificated aircraft.


What are the durations of strokes and events in a 4-stroke engine?

The duration of the stroke is simply the time the piston takes to run from the bottom to the top of the cylinder or vice versa, half a rotation.  So if the engine is running 2000 rpm, or 33.33 revolutions per second, or 16.66 strokes per second, the stroke duration is .06 seconds, half of one full revolution.

That's the physical mechanical stroke.  However the "events" overlap the strokes.  Ignition on an aircraft piston engine starts normally around 24 degrees before Top Dead Center, so the power "event" actually starts before the compression stroke is completed.  Same with exhaust; the exhaust valve may open slightly before the power stroke is complete (piston not quite at bottom dead center) and the intake valve may open just before exhaust stroke is complete.

This is all done to take advantage of inertial effects of the mass of the air fuel charge.  There is a lot of overlap of all these events with the mechanical stroke and is a function of valve and ignition timing, so for a given engine you need to look at a diagram of the timing points for ignition and valve opening/closing for that particular engine.


What causes a slight increases in indicated stall speed with altitude?

The U-2C (which the graph is for) had a stall speed of about 79 KEAS, that is 79 knots equivalent airspeed (EAS) at all altitudes. At 50000ft, 79 KEAS is about 80 KIAS (indicated airspeed), but at 75000ft, 79 KEAS is about 83 KIAS. This is simply a consequence of the way that indicated airspeed is measured by pitot-static systems - the measured speed is not quite a true representation of the effect of the airflow upon the airframe. So, the apparent increase in stall speed is just an artefact of the way airspeed is measured, rather than the performance of the airframe itself.

You can confirm the EAS/IAS conversions for yourself using the Hochwarth Aviation Calculator.


In an airplane wing, which control surfaces are primary, and which ones are secondary?

Generally speaking, if a wingtip fence or a winglet is there, it's fixed and can't be moved, so there is no question of it being used before or after the others, although since it's always there I supposed you could say it's used before any of the others. I say generally because I seem to recall hearing recently of an aircraft that has a movable winglet in some manner, but that may just be my imagination.

Insofar as labeling is concerned, control surfaces that are split—an inboard and an outboard section—are usually called just that, as in the inboard ailerons and the outboard ailerons.

Different makes of aircraft may have different orders of usage in some manner, but since your image pretty much matches that of a Boeing 747-100/200 (except they have no wingtip fence or winglet), let's use them for explanation.

The inboard ailerons, are always in use. The outboard ailerons come into use when the aircraft is in slow flight (relatively speaking), in other words, when slats/flaps are deployed. It's automatic, the pilots don't have to select using the outboard ailerons specifically.

The flap tracks (what you see on the image are the "canoes" covering the actual flaps tracks) move when the flaps are deployed. The flaps will usually operate fine even if a canoe leaves the airplane in flight (happened to me once), and as I remember you're allowed to defer replacing at least one of them, but with a performance penalty.

The movement of the slats is connected to the deployment of the flaps. Any flap selection results in the inboard slats being extended. On the 747, the inboard slats extend when the flap selection handle is moved to flaps 1°. When flaps 2° is selected, the outboard slats extend.

The flaps are deployed as called for by the pilots moving the flap handle to select whatever degree of flaps they want. On the 747 there are detents at flaps up, 1°, 2°, 5°, 10°, 20°, 25°, and 30°.

The spoilers/speed brakes (whatever you want to call them—the argument still rages—are deployed by the pilots using a handle, pulling it aft deploys them, and the inboard spoilers always deploy. Whether the outboard spoilers deploy depends on aircraft speed as determined by the flap setting: no flap deployment, no outboard spoiler deployment.


This page lists all the functional differences between the MAX series and the previous 737 variants. There are quite a bit of substantial changes like the reshaped tail cone and electronic bleed system. Not only are the engines different but the mounting pylon was changed to account for the new engines so you likely cant just "bolt on" the old engines. Even the cockpit has a different panel.


Why was the An-225 built when the VM-T Atlant already did the job?

As you can see in the second photo, the VM-T was unable to lift a fully-assembled Buran. The VM-T max payload is 50 tonnes, a Buran weighs on the order of 80 tonnes.

So for the VM-T flights they had to strip the Buran to get the weight down, including removing the tailplane.

The An-225 could lift a fully-assembled Buran, but was not ready in time, so they used the VM-T as an interim solution.


What is the difference between an air carrier and a commercial operator?

From 14 CFR 1:

Air carrier means a person who undertakes directly by lease, or other arrangement, to engage in air transportation.

Commercial operator means a person who, for compensation or hire, engages in the carriage by aircraft in air commerce of persons or property, other than as an air carrier or foreign air carrier or under the authority of Part 375 of this title. Where it is doubtful that an operation is for “compensation or hire”, the test applied is whether the carriage by air is merely incidental to the person's other business or is, in itself, a major enterprise for profit.

To make this more clear FAA Order 8900.1, Volume 2, Chapter 2, section 2 says:

2-128    TYPES OF CERTIFICATES UNDER PART 119. There are two, basic types of air operator certificates (AOC) issued to U.S. applicants who will conduct operations in common carriage. See Table 2-4, Certification for a summary of certificate requirements.
A.    An Air Carrier Certificate. This certificate is issued to applicants that plan to conduct interstate, foreign, or overseas transportation, or to carry mail.
B.    An Operating Certificate. This certificate is issued to applicants that plan to conduct intrastate transportation.

From your perspective it isn't a too important distinction.  As a commercial pilot all that matters to you is that both air carriers and commercial operators need to have operating certificates.  As a commercial pilot you can be hired by someone who has an operating certificate but you cannot provide the same services on your own unless you yourself have an operating certificate (e.g. a charter operator can hire you, but you cannot operate a charter service).
As a commercial pilot you can be paid to act as PIC and can engage in the commercial operations that are excepted from operating certificates in 14 CFR 119.1(e).  You cannot act as either an air carrier or a commercial operator without complying with 14 CFR 119, which requires that you have an operating certificate.


Is there a way to see the radar info ATC has?

If you are in or around NYC, flightradar24 will give you most, but not all, traffic including helos and ATC radar traffic.

flightradar24 most likely has several ADS-B receivers in that area that not only catch aircraft transponder/UAT output, but they also catch FAA ADS-B ground station broadcasts. The ground station will broadcast any known traffic (mode C radar traffic included) that ATC is aware of to any client aircraft that are in the area that have their ADS-B output configured to inform the ground station that they are capable of displaying traffic data. Most private GA aircraft with ADS-B are configured this way because there are iPad apps that will display it while airborne. The ground station will broadcast that traffic and a local flightradar24 receiver gets it too and up it goes on the website. The data may be limited to just aircraft in the vicinity of the client aircraft but in an area like NYC, there are typically many GA aircraft (clients) out there at any time that are configured as ADS-B in capable.


What happens when a helicopter loses an engine?

Helicopters are able to do something called autorotation if all thrust is lost.

  In a helicopter, an autorotative descent is a power-off  maneuver in
  which the engine is disengaged from the main  rotor system and the
  rotor blades are driven solely by the  upward flow of air through the
  rotor. In other  words, the engine is no longer
  supplying power to the main  rotor.

(Look in particular at the direction of flight arrows. Remember there's a lift vector coming of the blades as well in both cases.)

Basically, the collective is decreased immediately when thrust is lost for whatever reason. This allows the airflow coming through the blades to push them around, like a reverse windmill in a way, keeping the blades spinning. This also generates lift, keeping the helicopter generating some lift (while descending of course).

  At the instant of engine failure, the main rotor blades are
  producing lift and thrust from their angle of attack (AOA)
  and velocity. By lowering the collective pitch, which must be
  done immediately in case of an engine failure, lift and drag
  are reduced, and the helicopter begins an immediate descent,
  thus producing an upward flow of air through the rotor
  system. This upward flow of air through the rotor provides
  sufficient thrust to maintain rotor rpm throughout the descent.
  Since the tail rotor is driven by the main rotor transmission
  during autorotation, heading control is maintained with the
  antitorque pedals as in normal flight.

Once the helicopter reaches ground, the pilot will pull up. Since the blades were spinning a bit faster than needed for a hover since he was flying forward the whole procedure, he simply pulls up and levels out carefully close to the ground until the helicopter touches down.

This being said, you have to be careful, since if you're flying to slow you can't pull it off.

  When landing from an autorotation, the only energy available
  to arrest the descent rate and ensure a soft landing is the
  kinetic energy stored in the rotor blades. Tip weights can
  greatly increase this stored energy. A greater amount of rotor
  energy is required to stop a helicopter with a high rate of
  descent than is required to stop a helicopter that is descending
  more slowly. Therefore, autorotative descents at very low or
  very high airspeeds are more critical than those performed
  at the minimum rate of descent airspeed.

This dangerous conditions are shown in a height-velocity diagram as is seen below, in this case apparently from an R44.

Here's a little video to get an idea of how it looks for the pilot:

Autorotation is often time critical and has to be done right as there's only one shot and as such is practised by pilots on a regular basis.

All extracts in this section are from "Helicopter Emergencies and Hazards" by the FAA, an excellent and very extensive publication on the topic.


What happens if only rudder is applied in a turn without ailerons? Do the two have to be applied together all the time?

To turn – any vehicle, not just an airplane – you need to generate corresponding centripetal force.

When you only apply rudder, the plane will turn a bit, but because unlike boat it has no keel, it will not generate much centripetal force, just fly somewhat sideways, which is called a skid. It will produce more drag this way.

Now any well designed plane has yaw-roll coupling, which will cause it to bank into the turn anyway. It is caused by the slight increase in speed of the outside wing, and the dihedral most wings have resulting in increase in angle of attack, thereby increasing lift on the outside wing. So you can make the plane turn with just the rudder, but it will be inefficient, and it will be slower as the yaw-roll coupling will take its time.

On the other hand if you apply just the aileron, the plane will bank into the turn as usual. However, there will be some slip, as the deflected ailerons cause an adverse yaw – the aileron deflected down, which is on the outside wing, causes more drag – so the plane will actually turn a little less than it should. Like skid, that will cause extra drag.

What you want to do is bank into the turn with ailerons, and use rudder to compensate the various drag asymmetries to keep the slip-skid ball centered. That will give you least drag. Different planes will need slightly different application of rudder.

There are cases where you will want to apply ailerons and rudder in different combinations (as mentioned in comments below):

On the ground you steer with rudder, while using aileron to prevent wind from tipping the plane sideways – the landing gear provides the centripetal force in this case.
During cross-wind landing, you need to align the plane with the runway, but as it flies relative to the air, it tends to drift sideways. You need to make it fly sideways relative to the air instead by banking into the wind while using opposite rudder to prevent turning.
The same combination applies during cross-wind take off, aileron into the wind to prevent wind from tipping you over sideways and rudder to compensate for weathervaning.
You can also use bank with opposite rudder to increase drag if you are too high and fast on the approach – this is called forward slip. Just don't let the airspeed decay too much, because stall in slip or skid is more likely to result in a spin.


Why does the B737NG need electrical power for aircraft towing?

You need power for lighting, fans, intercom, and CVR/flight recorder, cameras; any and all of them are required for towing an aircraft, depending upon its size, and in the event of an accident.

See:

"Aircraft Towing":

Accidents and Incidents

  "B763, Luton UK, 2005 (On 16 February 2005, at Luton Airport, a Boeing B767-300 collided with the tug pulling it forward when the shear pin of the unserviceable tow bar being used to pull the aircraft broke. The aircraft ran onto the tug when the ground crew stopped the tug suddenly. As result of the collision with the tug the aircraft fuselage and landing gear was damaged.)"

  "JS41, Birmingham UK, 2007 (On 26 June 2007, at Birmingham Airport UK, a BAe Jetstream 41 started an engine running pushback without using intercom between ground crew and flight crew. The pushback could not be completed as the towbar could not be disconnected and confusion over a decision to return the aircraft to the gate resulted in an attempt to do so with the aircraft brakes selected which caused the aircraft nose landing gear to collapse.)"

"Pushback":

  "The responsibilities of the ground crew team carrying out a pushback include ensuring that no part of the aircraft structure will impact any fixed object or other aircraft and may include giving clearance to start one or more engines just before, during or immediately after a pushback. The number of people assigned to a ground crew team for a pushback may vary according to aircraft size, but in most cases will be at least three. One will be driving the pushback vehicle, one will be walking in the vicinity of one of the aircraft wingtips and looking beyond the aircraft tail and one will be in charge of the manoeuvre and in communication with the person with aircraft responsibility in the flight deck. Communication between the ground crew supervisor is usually by means of a plug in to an aircraft ground intercom circuit; if so, this is facilitated by a ground crew microphone which acquires the voice of the user whilst excluding background noise, which if the aircraft engines are running can be considerable. If only two ground crew are used for pushback of a smaller aircraft then it is important that the procedure takes full account of the roles of each ground crewmember and that the person in charge of ground crew communications on the flight deck is aware of the number of ground crew being used and the physical location of the supervisor. ...
  Observations of abnormal circumstances in connection with engine starts or any other matter affecting, or potentially affecting the safety of the aircraft during a pushback are of great importance to those on the flight deck but it is essential that any descriptions of external observations during engine starts are imparted accurately; this may sometimes be demanding using ground intercom but can be extremely difficult with only hand signals available.".

Accidents and Incidents

  "A332, Karachi Pakistan, 2014 (On 4 October 2014, the fracture of a hydraulic hose during an A330-200 pushback at night at Karachi was followed by dense fumes in the form of hydraulic fluid mist filling the aircraft cabin and flight deck. After some delay, during which a delay in isolating the APU air bleed exacerbated the ingress of fumes, the aircraft was towed back onto stand and an emergency evacuation completed. During the return to stand, a PBE unit malfunctioned and caught fire when one of the cabin crew attempted to use it which prevented use of the exit adjacent to it for evacuation.)
  ...

  "B738 / B738, Toronto Canada, 2018 (On 5 January 2018, an out of service Boeing 737-800 was pushed back at night into collision with an in-service Boeing 737-800 waiting on the taxiway for a marshaller to arrive and direct it onto the adjacent terminal gate. The first aircraft’s tail collided with the second aircraft’s right wing and a fire started. The evacuation of the second aircraft was delayed by non-availability of cabin emergency lighting. The Investigation attributed the collision to failure of the apron controller and pushback crew to follow documented procedures or take reasonable care to ensure that it was safe to begin the pushback.)"

There are additional examples available at those links which were not quoted. Sometimes there are external cameras which are useful to record towing operations in the event of an accident.


To use the equipment suffix "G", does the GPS have to be certified for IFR?

Yes, using GPS for IFR requires a certified unit. The AIM 1-1-17(b)(2) says (emphasis mine):

  Authorization to conduct any GPS operation under IFR requires:

  (1) GPS navigation equipment used for IFR operations must be approved in
  accordance with the requirements specified in Technical Standard Order
  (TSO) TSO-C129(), TSO-C196(), TSO-C145(), or TSO-C146(), and the
  installation must be done in accordance with Advisory Circular AC
  20-138, Airworthiness Approval of Positioning and Navigation Systems.
  Equipment approved in accordance with TSO-C115a does not meet the
  requirements of TSO-C129. Visual flight rules (VFR) and hand-held
  GPS systems are not authorized for IFR navigation, instrument
  approaches, or as a principal instrument flight reference.


Are “Kennedy Steve’s” various jokes allowed in ATC communications?

(US-based answer)

Yes, it's legal. Yes, everyone - including pilots - is held to the same standard of professionalism. And there are no real consequences for anyone (usually). The simple fact is that we're all human beings and humor, slang and jokes are all part of how we communicate and even handle stress.

Legally, the FAA doesn't regulate radio communication, the FCC does. Of course, the FAA has aviation regulations and guidelines that apply, but they're very general (as they should be). Using standard phraseology is strongly encouraged at all times for clearer, quicker communication. The ATC orders 2-4-14 say:

  Use the words or phrases in radiotelephone and interphone
  communication as contained in the P/CG or, within areas where
  Controller Pilot Data Link Communications (CPDLC) is in use, the
  phraseology contained in the applicable CPDLC message set.

In other words, stick to standard phrasing. But there's nothing in there about avoiding humor or jokes.

As for different controllers, they all follow the same standards for radio use no matter where or on which frequency they're working. In my experience, the quieter the frequency the more likely it is that someone - controller or pilot - will joke or even have a brief conversation. I was once taxiing a C172 to the far end of a 12,000ft runway - which takes some time - and the tower controller asked me a few short questions about my accent, where I was from etc. But I was the only aircraft on his frequency at the time and I'm sure he wouldn't have done it if it would have impacted operations or safety in any way.

Which brings me to your final point. In normal circumstances, no one cares about this stuff at all because a) it has no significant impact on anything, and b) it makes life a little more interesting for everyone. It's practically impossible to fly cross-country for more than half an hour without hearing someone make a joke, chat with someone else (briefly), or even complain about something. And again, in normal circumstances that's completely fine: no one expects pilots and ATC to act like robots with a limited vocabulary.

But, if a joke or non-standard phraseology causes offence or a misunderstanding or - in the worst case - an incident of some kind then the FAA or NTSB could be interested. This column from NASA's ASRS team has some examples of reports of problems causes by non-standard phraseology, including this one:

  "I called for clearance to St. Louis as follows: 'Clearance delivery,
  company ident, ATIS info, federal aid to St. Louis.' Federal aid was
  meant to mean FAA clearance in a joking fashion. The Controller
  misinterpreted this to mean that we were being hijacked and called the
  FBI and airport police...I used no 'standard' phraseology to indicate
  nor was it my intent to indicate we had a hijacking...I will use
  absolutely standard phraseology in the future..." (# 248982)

And this incident got quite a lot of attention, even outside the aviation press. I don't think it makes sense to say that it's 'more serious' for ATC to make jokes than pilots because every incident is different anyway.

All in all, joking on the radio is like joking in any professional context: if it doesn't disrupt your work or other people's work, if you're not insulting people or wasting their time, and if you're not saying anything stupid or dangerous then no one really minds.


Can "Center" provide VFR flight following?

Any US radar facility can (and will, workload and coverage permitting) provide VFR Flight Following, whether Approach/Departure or Center.
Look up the airport you are departing or, if already airborne, the nearest airport in your general direction of flight in your A/FD, EFB or (if you’re lucky) glass panel. The App/Dep lines will give you the frequency and name of the facility to call in that area.
The coverage problem is mostly an issue of altitude rather than range. Center radar and radio sites are further apart, so due to terrain and the curvature of the Earth, they may not be able to see/hear you if you’re too low. Typically 3,000 AGL is high enough, but if not, just keep climbing and try again in a few minutes.


Are composite materials, which are being widely used in newer aircraft, better at handling bird strikes?

Out of the box, no. They are worse at handling birdstrikes. But with some thought they can be made much better.

All materials have an elastic range of deformation, and if that is not exceeded, they will assume their original shape without damage. Composites fail if this range is exceeded. First the fibers with the highest elongation fail, which enables the other fibers to take more load, but at some point too few fibers remain, and the part fails catastrophically. This is audible: The first small failures cause a faint crackling, and the eventual failure a loud bang.

Metals add a plastic deformation before ultimate failure, and this enables them to absorb a lot of energy in the process. Since energy is force times distance, the small elastic deformation will not absorb much energy. However, the plastic deformation is magnitudes bigger and makes metals the much better energy absorbers. Even a deformed structure can take a sizable fraction of the load it took before deformation. A birdstrike will cause a dent, but the rest of the structure will not see much of the load since the dent-forming could absorb a lot of energy. However, the changed contour can provoke changed aerodynamic loads, so new failure modes might result.

Impact loads on composites have a second disadvantage: The impact creates shockwaves which travel through the structure and cause delamination (separation between fibers and resin matrix) when they hit a boundary. Therefore, the biggest damage occurs on the opposite side of the impact. A birdstrike might not leave a visible dent on the outside, but can shatter the material on the opposite side such that the structure will break at a fraction of the load it would have carried without the bird strike.

Therefore, some composite wings use metallic leading edges to protect the composite structure from birdstrikes. But also the composite structure itself can be improved: If very tough fibers like Kevlar or Spectra are added, the impact energy will not break those fibers, and the load will be distributed over much more of the resin matrix. This will delay delamination, and when it happens, it will be spread over a bigger area and cause the fibers to break at multiple locations. The energy needed for the widespread delamination and the multiple fiber failures will increase the energy absorption dramatically. This structure must be designed as a protective armor, so the load-carrying structure below is not affected. Proper crashworthy design with composites allows to make the structure even tougher than a comparable metallic structure.


Is this route of a airforce jet on flightradar faked?

No, that has not been faked.

Flightradar is updated with a low frequency (from that screenshot I'd estimate once per 10 seconds, maybe more). This is done to reduce the computational demands on both the service that sends the radar info to Flightradar, and on the Flightradar servers.

Each dot in the track is one position update, and the website software just draws straight lines between them, which results in sharp corners. The real flight path will have a radius.


See the Interagency Air Cartographic Committee (IACC) Specifications:

  [IACC 2] 3.9.3.8 Compass Roses

  Compass roses, as illustrated in Appendix 6, shall be shown centered on all VHF NAVAIDs, when space allows.

  Preference shall be given to those serving enroute functions or located in areas not served by other VHF NAVAIDs.

  [IACC 5] 3.7.4.5 Compasses Roses

  Compass roses shall be charted centered on those NAVAIDs which have routes predicated on them. Compass roses may be shown around other NAVAIDs where placement of the compass rose does not create additional unnecessary clutter or congestion. If compass roses overlap and congestion hinders readability, the compass rose of the NAVAID with the most congestion may be deleted. Compass roses shall be shown oriented to slave magnetic North. Cardinal direction values shall not be shown. Compass roses shall be .75" in diameter and in very congested areas may be reduced in size to .5" in diameter.

In groundschool I was taught that this is actually based on VOR service volumes (which otherwise aren't explicitly marked at all on VFR sectional charts): the compass rose is not shown around VORs with Terminal service volumes. This might be a general rule, but it is not entirely true however. You provide a perfect example: OJC and RIS are both Terminal VORs.

The key differences: 1) OJC has the V10-12 airway, and 2) map is more congested around RIS.


How does one train for making landings and takeoffs in bad weather?

Your question has two components: 1) how do pilots train for adverse conditions and 2) how do pilots stay fresh on adverse conditions?

As you said, smaller airplanes (really, slower airplanes) are hardest, because the wind speed is a larger percentage of the airplane's flying speed. There are no real simulators for small airplanes: we learn by going out and doing. When you first learn to fly, your instructor makes sure you can handle crosswinds and gusts. With the Instrument Rating comes more adverse weather.

Once you have learned the techniques (and stay proficient by practicing regularly), faster airplanes and higher winds are not really a problem -- the same techniques apply, and in any case you will have a more experienced pilot or instructor helping you along.

I must call out your use of "newbie pilot" -- I hope you're not implying that airline pilots are newbies in any sense of the word. Before you can even hope to get an airline job you've already experienced bad weather in marginal airplanes.

Now, staying proficient: this is where transport airplanes (airlines) are very different from the small airplanes. The airlines' pilots practice regularly on simulators that really can duplicate just about any kind of weather you'd fly in. Pilots of small airplanes though... the simulators can't do that, and we practice in the real world.

All that said, a passenger's idea of what makes a good landing is very different from a pilot's! A passenger thinks a smooth touchdown is what makes a good landing. For a pilot, a good landing means a stable and controlled approach followed by an appropriate touchdown that maximizes safety -- in gusty crosswinds a firm touchdown is much safer than a greaser.


What is the difference between a pitot tube and a pitot-static tube?

A pitot probe strictly measure ram air pressure, commonly called "pitot pressure" or Pt pressure. A pitot tube measures pitot pressure and pitot pressure only. A separate static port is required to measure static pressure (Ps) and will usually be located on a section of the fuselage where airflow is minimized.

A pitot-static port is a combination pitot AND static port. That is, the tube itself has an opening for detection of Pt pressure and one or more openings for static pressure. In this case, there generally is no static port on the fuselage since it's built into the pitot-static probe.

TLDR: the only difference between the two is that a pitot-static probe is a pitot probe with static ports whereas a pitot tube is strictly just a pitot tube. :-)

Edit: Not sure if the original question was edited after my answer or if I missed the second part in my original response... Static pressure is required to know indicated airspeed because as altitude increases, airspeed increases due to less air resistance.


What do all the indicators on a HUD mean?

HUD symbology varies depending on flight mode and aircraft configuration so you will find a wide variety of symbols capable of being displayed.  Some basic ones from the F/A-18 E/F aircraft are.

To your original question the ‘W’ symbol is called the Waterline symbol and represents the point at infinity where the longitudinal axis of the aircraft points toward.  It is analogous to the miniature airplane symbol on an attitude indicator.  A similar symbol called the Gun Cross is used on the F-16 HUD.

On high performance aircraft capable of high AoA operations, the waterline symbol is not as useful as the Flight Path Marker or Velocity Vector symbol which indicates the point at infinity the aircraft is currently trending towards.


Other than a swing wing, what types of variable geometry have flown?

Extending wings

The idea is to have a larger wing area at takeoff for more lift and a smaller wing area in flight for more efficiency.

The NIAI RK and followup RK-I used two tandem wings that served as rails for an extendable panel that could be rolled out between them.

The project failed because Stalin was so enthusiastic about it he had it use the most powerful engine available which was too unreliable. I can't find a reason why the concept was not tried again.

The German FS-29 glider of 1972 had a different arrangement. It had an outer wing that fit over an inner wing and could unsheathe like a sword. Only one was built.


What devices measure EPR & RPM on a turbofan engine?

RPM is measured by a device called a tachometer. In a jet engine often this will be an inductive proximity probe that is measuring a toothed wheel on the shaft.

EPR is measured by comparing two static pressure sensors, one at the inlet and one at the propelling nozzle discharge, and taking the ratio. There are many different types of these. Many common ones will have a flexible membrane or diaphragm of some kind. Under pressure the membrane deflections and then you use some kind of deflection measurement.

These types of sensors are very common in many applications besides just jet engines. A little research on the internet will show you lots of details about how they are constructed and how they work.


What and when was the first gyroscopic flight instrument introduced?

It appears that the first gyroscopic flight instrument in aviation was a gyroscopic stabilizer, with the purpose of maintaining stability and control in a Curtiss C-2 biplane; it was first used (publicly) in 1914.

For this, the inventors, Elmer A and Lawrence B Sperry were awarded the Collier Trophy in 1914. Apparently they did this by,

  ...linking the control surfaces with three gyroscopes, allowing flight corrections to be introduced based on the angle of deviation between the flight direction and the original gyroscopic settings.

Lawrence Sperry and gyroscopic stabilizer, Image from wright-brothers.org

The device (with the gyroscopes spinning at 7000 rpm) was first tested by Lawrence Sperry and Berringer on a Curtiss F aircraft in 1913, with the first public flight in 1914.

Sperry’s second flyby in Paris in the 1914 competition, with Emil on the wing. Image from historicwings.com

Elmer went on to develop the turn and bank indicator and an optical drift indicator, for which he was awarded the Collier trophy again in 1916.


How are winds aloft forecasts derived in the USA?

I took a tour of my local NWS office and spoke to the aviation weather unit people. My 8yo daughter even got to help launch that day's weather balloon, and then we went inside and monitored the balloon's data as it ascended.

One of the data streams was the winds, which prompted me to ask: ok, so we know the winds right now for this location, but how does this knowledge allow you to forecast 24 hours into the future? And secondly, there are more FB locations that there are weather balloon sites, so how does that work?

Here is the answer:

Data from the balloons are just 1 of many factors entered into the weather forecasting computer models, and the FB products are actually the result of two different modeling systems. The first two products (the 6hr and 12hr forecasts) are generated by the Rapid Refresh (RAP) modeling system, and the third product (the 24hr forecast) is generated by the North American Mesoscale Forecast System (NAM) model.

Both models produce numerical forecast data on a grid, with each grid point being 13km apart in the RAP model and 12km in the NAM model, and each grid point containing 50 vertical data points up to the 10mb level. From these data points, each "FB Location" is interpolated (both horizontally and vertically) to the geographical location of the depicted airport, and the various forecast altitudes.

Additional reading:

FAA AC 00-45H Aviation Weather Services. (This document explains U.S. aviation weather products and services. It provides details when necessary for interpretation and to aid usage. Chapter 5.13 discusses the FB product)
NWS Instruction 10-812 Aviation Wind and Temperature Aloft Forecast. (This instruction provides guidance to NWS offices, outlining preparation and format of wind and temperature aloft forecasts in support of commercial and general aviation. It also lists each location where a forecast is provided)

Interesting Trivia:

All forecast locations correspond to an airport, except for 7 locations in the Gulf of Mexico, 1 location off the east coast of northern Florida, 5 locations in the Gulf of Alaska, and 1 location near the end of the Aleutian chain. These 14 additional forecast locations correspond to heavily traveled air routes.
The RAP model runs hourly, and provides forecast data 21 hours into the future.
The NAM model runs every 6 hours, and provides forecast data 84 hours into the future


Does pilot monitoring have authority to go around in exceptional circumstances?

The captain is the captain, so when he says "go around" then the PF needs to initiate the go-around.  If the FO doesn't initiate the go-around as directed, then the captain can (at that time as at essentially any other time he sees it necessary) take over control of the aircraft.  That's the captain's authority and it's pretty clear.

The other case is slightly less clear, but only slightly.

Most operations probably have a directive along the lines that the PF is required to go around when the PM so directs.  So if the captain is flying and the FO directs a go-around, what the captain/PF should do is perfectly clear.  If he doesn't do so, the next step is probably spelled out in the operations manual; probably something along the lines of, repeat the directive once, then assume incapacitation and take over the controls to execute the go-around.

The really bad case would be, the captain is intent on landing regardless and the FO believes that they're about to crash.  At that point, the question (really for both pilots) becomes, are you sufficiently sure of your position that fighting for the controls close to the ground is less dangerous than doing what the other pilot wants?  If we're somehow down to our last minutes of fuel & the copilot wants to go around because a dog ran onto the runway, a reasonable captain would probably overrule him and land anyway.  If the captain is so intent on landing that doesn't see the aircraft on the runway that he's about to  land on top of, a reasonable copilot might push the throttles forward like his life depends on it.

If you've reached the point where "go around" "go around" "I have the aircraft, go around thrust" hasn't worked, you've left the realm of most manuals.  The implicit assumption is that an incapacitated PF isn't going to have the capacity to fight you for the controls; I doubt very many operations manuals devote much space to the nightmare case of wrestling for the controls against a maniac determined to do something awful.  Thankfully, such scenarios are almost entirely the stuff of imagination -- commercial flight is essentially the safest form of transportation ever known to mankind.  That remains true even though the one in (very literally) millions of flights where something does go horribly wrong (Germanwings crash into the Alps, etc) gets extraordinary publicity.


The first "practical" autopilot was invented by George DeBeeson (the patent can be found here, updated here) - This seems to be the most likely reason for the informal name "George" for the autopilot system on aircraft.

Autopilots are also sometimes called "Otto" (as in Otto the Autopilot from Airplane!, and our very own chat bot, but this seems to be less common than "George".


What is the name of the Instrument that indicates roll?

The only1 instrument that directly indicates the bank angle is the attitude indicator, also (especially formerly) known as the "artificial horizon".  As another answer has noted, many other instruments give indirect indications of bank angle, and by using them appropriately, it is quite possible to keep the wings level even with no direct indication of the bank angle.

The magnetic compass (even of the simple "wet" type) could be added to the list of instruments that indirectly indicate bank angle, though its use is very limited.  (For example, at mid-latitudes in the north magnetic hemisphere, it is generally not feasible to rely solely on a magnetic compass for bank attitude control, even in very smooth air, on headings that lack a significant southerly magnetic component.)2  It would be very challenging to use a magnetic compass to keep the wings level in any significant amount of turbulence, even if the pilot were free to choose a target heading that gave optimal perfomance of the compass.

The inclinometer doubles as a bank angle gauge if the aircraft is kept on a linear flight path.  Since any deviation from wings-level flight generally causes the flight path to curve, the inclinometer is of no practical value for keeping the wings level in clouds.

Beware of the term "turn and bank indicator".  This is another name for the needle-and-ball turn rate indicator, or its vintage British equivalent that has a second pointer arm in place of the ball.  But the ball-- also known as the "inclinometer"-- or the second pointer arm-- really just indicates sideslip, not bank angle.  As noted above, only if the flight path is constrained to be linear does the inclinometer reading correlate to the bank angle, and that is not a realistic constraint for most cloud-flying situations.  A better name for this instrument is "turn and slip indicator".  A more common name in modern times for this instrument is simply "turn rate indicator", with the fact that a slip-skid ball (inclinometer) is mounted in the same housing going unmentioned.

Footnotes:

1-- Here's a notable, but rarely-seen, exception to this statement-- the "Bohli" compass is a specialized compass for use in gliders.  One of its many advantages over a more conventional magnetic compass is that it provides some direct indication of bank angle.  See these related ASE answers for more about it-- How can pilots fly inside a cloud? , Is it normal for gliders not to have attitude indicators?

2-- Same as footnote 1!


In what airspace may gliders fly in clouds in the UK without an IFR flight plan and without contacting any air traffic control facility?

Broadly speaking, the UK is Class G, excluding airways and terminal areas, from surface up to FL195.  Can hop in your aircraft and fly IMC without talking to anyone to your heart’s content


Why do we lean the mixture when the air become less dense?

The decrease in air means less oxygen. If the fuel is burnt at "rich" there would not be enough oxygen in the air to burn some of the fuel, thus reducing efficiency, increasing the risk of carbon monoxide, and adding grime to the exhaust system. That is why "lean" is used for high altitudes, to burn efficiently and safely.


Why are rules regarding the use of oxygen masks by commercial pilots often ignored?

The rule you've found is under part 135 of the FARs, which generally governs commuter and on-demand operations like many charter flights. Most commercial airlines, such as those flying large passenger jets on regularly scheduled routes, are part 121 operators, which follow different rules.

For part 135 operators, there are a few caveats. First, above 25,000 MSL, there is an exception to the oxygen requirement if "each pilot has an approved quick-donning type oxygen mask." If the aircraft is so equipped, masks are only required above 35,000 MSL or when one pilot has left the cockpit.

The rules for part 121 operators are a bit different and can be found in 14 CFR 121.333. Under these rules, if quick-donning masks are available and the aircraft has more than 30 seats or a payload capacity of more than 7,500 lbs, oxygen is not required at or below FL410 unless one pilot has temporarily left the controls.

Since the majority of videos you may see online probably involve two pilots flying a large part 121 airliner (or one under a foreign regulatory regime, where different rules apply), oxygen masks would not be required in most of the situations where cockpit films are released.

That said, I found this article, which may be of some interest: Study: Pilots Ignore Oxygen Regulations. It cites the results of a survey conducted as part of a student's master's thesis which concludes that the rules are ignored quite often and that there really aren't effective ways to enforce them either:

  The compliance numbers for Part 121 respondents were higher, with 39
  percent reporting always using oxygen when required above 25,000 feet
  and 48 percent above 41,000 feet.

  Part 135 respondents were nearer the Part 91 results, with 21 percent
  saying they always use supplemental oxygen when only one crewmember is
  at the controls above 25,000 feet and 18 percent continuously using
  oxygen when flying above 35,000 feet.

So for part 121 operators, the primary time when the regulation is relevant is when one pilot has left the cockpit above FL250. The article goes on to discuss some of the reasons pilots may not follow the regulation and whether the regulation makes good sense. Some pilots on the PPRuNe Forums discussed the rules here (before they were changed to FL410) and also here. One author notes, with regard to donning masks during bathroom breaks, that "there is probably no more violated FAR in US operations than this one." Several reasons are posited in those threads, among them:

Some non-military pilots do not receive decompression chamber training, and so do not have an appreciation for the effects of severe hypoxia and its dangers
This practice would use up much of the cockpit oxygen supply, especially on long-haul flights, leaving less available in the event of an emergency (some information on how long oxygen supplies tend to last)
The expense and time involved in topping off oxygen tanks all the time if they were routinely used.
A desire to reduce the complexity of single-pilot operations during breaks, not wanting the remaining pilot to complicate things by donning the mask and adjusting audio settings accordingly instead of focusing on the aircraft
In some cases, restowing the masks may require maintenance personnel after the flight, which is impractical
The same rules do not apply under many other regulatory regimes, which leads people to conclude they are unimportant

Note that some pilots discuss using the masks routinely, both to ensure that their operations are as safe and legal as possible, and to give the crew practice and experience in donning and using the masks so they will be comfortable with them in the event of an emergency.


In a Cessna 172 flying VFR on long final, when do I extend flaps to 10, 20, and 30 degrees?

I visualise the standard lengths of the pattern and pretend I'm simply doing them in a straight line.

I'm sure you could figure out precise lengths or time intervals if you wanted to, but ultimately in a 172 in VFR you don't need to be exact - you just need to be fully configured and established by the usual point on final approach, as if you were completing a circuit.

The trap many people find with a straight-in approach is they leave everything too late - downwind checks, flap, etc. Make sure you allow enough room for about 15-30 seconds between flap extension, otherwise you'll find it difficult to maintain the approach angle.

As with everything, a good straight in approach takes practice!


Why are some LNAV/VNAV mins lower than the LPV mins for the same approach?

From what I could find out, it looks like they're unusual cases produced by the obstacle clearance calculations. There's a lengthy thread on PoA about it and the main points I saw are:

LNAV/VNAV and LPV approaches are designed differently (the specifications are in FAA Order 8260.58)
The Obstacle Clearance Surface (OCS; an imaginary zone that must be free of obstacles) is shaped differently for each approach type
The OCS isn't at a fixed angle: it depends on the designer's choice of glideslope angle (e.g. for terrain clearance) and - in the case of LNAV/VNAV - on the prevailing temperatures at the airport
The two approach types have decision points at different distances from the runway threshold, which also affects the glideslope requirements
The resulting OCS may be at a higher angle for LNAV/VNAV than for LPV

The FAA Order has a lot of formulae to work it all out, but apparently the result is that if the calculations come out in a certain way and there's an obstacle close to the runway, it can penetrate the LPV OCS but not the LNAV/VNAV OCS. That means the LPV DA then has to be made higher.

In the PoA thread, every example of an approach with LPV minimums above LNAV/VNAV has an obstacle close to the runway. But the consensus was that the LPV minimums being higher than LNAV/VNAV is still very unusual overall.

Finally, although this isn't exactly the same scenario, an old FAA article on GPS approaches mentioned that the minimums aren't always what you would expect:

  While [varying the obstacle clearance for an LNAV/VNAV approach] occasionally results in minima higher than the LNAV
  minima, the added safety benefit of a stabilized descent outweighs the
  difference in minimums

(That all refers to altitude, of course. The other part of the minimums is the visibility, but that should increase anyway as the DA and/or category increases. A high, fast aircraft needs to be able to see the runway from further away in order to descend safely.)


Can I log my military training time as PIC, if I have a PPL?

For FAA purposes you can log PIC time in the T6 because you hold a license in the airplane, single engine, land category and class.  However, the USAF might not see it that way.

Since you do not have an FAA license for the category and class multi engine land, you can only log PIC time for your solo flights in the T38.


Can an aircraft (civilian or military) land with its brakes already engaged?

Can an aircraft land with its brakes already engaged at the max
  landing speed of that aircraft?

Yes...

Im gong to assume that by brakes engaged you mean to full, preventing the wheels from spinning. First Lets consider the two different types of planes. Tail wheel planes will most likely nose over depending on how the plane is landed. A tricycle gear equipped plane will most likely grind through the main gear. Remember the nose gear does not generally have a brake (in my GA experience it never has a brake).

Although I would not advise it. It depends really what you mean by "can it land" it will touch down and the tires will simply lose traction and start skidding (eventually to a stop). The results (on a dry runway) may be similar to what we saw with JetBlue flight 292 which had its nose gear turned 90 degrees. The gear was basically ground through like it was sanded down. The tires in this case will all begin to heat up severely and eventually fail. My guess would be that the skidding will vary from side to side and cause the plane to weather vane quite a bit as if differential braking were used.

You may also damage the runway quite severely.


Please tell me which trainer aircraft is this?

Its a Zenair Zodiac CH601 XL you can see the registration code on the side and if you watch the video a bit more they show the inside of the cockpit and you see the registration code a bit more clearly, which you can look up here. It appears to be owned by this flying club.


Does the 747-8 / A380 nose-wheel encounter more weight during braking?

Yes of course. And even with nose wheel brakes the main braking force would still be generated by the main wheels, so a substantial pitching moment is generated.

Now for a crude first-order approximation. We have an answer about the braking forces here, and using those 235 kN per wheel (the 747 has 16 main wheels) means that the center of gravity, which I guess to be at least 6 m above the ground, experiences inertial loads of 3,76 MN. This needs to be reacted in a moment around the main wheels with the lever arm of the wheel base. This is conveniently displayed in the drawing below and is 25.6 m. Thus, the reaction moment around the main wheels requires a nose wheel load of 881 kN in addition to the regular load of the nose wheel (which is maybe 5% of the aircraft's gross weight or 196 kN).

Boeing 747 side view (picture source)

Since the highest friction coefficient is reached at low speed, wing lift or tail downforce will not play a significant role. Braking to a full stop after an aborted take-off at full gross weight will load the nose wheels with a multiple of the static load of more than four.

In a normal landing, the forces involved are much lower and the multiple is close to one. This is really a quick back-of-the-envelope calculation, but the magnitude should still be right.


Taking your questions in order:

  Do people who have flown in B-2 Spirits have the Air Force handle "Spirit ###?"

It's plausible. The author of the article says so and there doesn't seem to be any reason to lie about such a trivial detail. That said, he also refers to the pilot as "Scar" rather than as "Spirit [whatever]" so even if Spirit-number is a callsign that a pilot has earned, it doesn't mean it's necessarily the one that they'll always fly with.

  If so, which regulation/directive/etc. specifies that the handle of people who have ever flown in the cockpit of a B-2 Spirit be "Spirit ###?"

There seem to be no such regulations, or if any do exist, they are applied individually. Pilot callsigns are generally given informally, according to this article, which is not an official military publication. Although the content of this article is unfortunate, it substantiates the first one. Finally, the Air Force publishes official voice call sign guidelines, which do not list regulations for pilot callsigns.


What's the difference between TWEBs and TIBS?

NOAA has a great guide on their website called A Pilot's Guide to Aviation Weather Services which covers these (and more)!  They actually describe it better than I could.

The short version though is that TIBS is a telephone weather service while TWEB is a recorded route briefing that you can listen to while airborne.  Both are used for supplemental information and don't replace an official briefing.

  TIBS Telephone Information Briefing Service
  TWEB Transcribed Weather Enroute Broadcast
  PATWAS Pilot's Automatic Telephone Weather Answering Service

  TRANSCRIBED WEATHER BROADCASTs (TWEB) are continuous broadcasts of
  recorded NOTAM and weather information prepared for a 50-nautical mile
  wide zone along a route and for selected terminal areas. TWEBs are
  broadcast over selected NDB and VOR facilities and generally contain a
  weather synopsis, in-flight advisories, route and/or local vicinity
  forecasts. Winds Aloft Forecasts, current weather reports, NOTAMs, and
  special notices. TWEB outlets are listed below by state:

  PILOT'S AUTOMATIC TELEPHONE WEATHER ANSWERING SERVICE (PATWAS), and
  the TELEPHONE INFORMATION BRIEFING SERVICE (TIBS), provide continuous
  recordings of weather and aeronautical information. The information
  may include area and/or route briefings, airspace procedures, and
  special announcements. Telephone numbers for PATWAS and TIBS locations
  are found in the Airport/Facility Directory.

  TWEBs, PATWAS, and TIBS are for preflight or inflight planning and
  should not be considered a substitute for formal preflight briefings.


The aircraft is a Basler BT-67, which is a retractable wheeled ski equipped undercarriage STOL aircraft. It is a remanufactured DC-3 with Pratt & Whitney Canada PT6A-67R turboprop engine. The modifications include lengthened fuselage, increased MTOW, new avionics, redesigned wingtips etc. The skis are added in Canada.

Reports indicate that the aircraft includes an ice radar system, airborne gravimeter, airborne magnetometer and onboard laser radar system.

It is called a 'polar' airplane because it is owned by the Chinese Arctic and Antarctic_Administration. The aircraft is used by quite a few other missions in Antarctica, like Australia and the US, all operated by the Kenn Borek Air.


Precision Approach systems: Why is ILS used more frequently than PAR and MLS?

At least in the U.S., ILS is popular because it is popular. It's relatively cheap to install and operate, the receivers share technology with VOR, and it is already installed everywhere. Momentum (and cost of replacement) has a lot to do with the failure and success of navigation systems.

MLS requires new hardware on the ground and in aircraft. The FAA tried to roll it out in the U.S. in the 80s, with a goal of replacing ILS by 2010, and utterly failed. The equipment was expensive for aircraft and ground facilities, and the cost of developing the approach procedures was high, as well as each approach needs tailored antenna programming (ILS is reasonably standardized). The adoption rate was low and the benefits (better arrival area guidance, better accuracy in some cases) were duplicated by the much cheaper GPS.

Precision GPS (LPV or LNAV/VNAV approaches) only appeared with the development of the Space Based Augmentation System (SBAS), also known as the Wide Area Augmentation System (WAAS). Augmented GPS has higher vertical precision and allows a single navigation system to be used for enroute, terminal, and precision approach guidance, a huge cost savings. The relatively new Ground Based Augmentation System (GBAS, originally called LAAS) adds high precision approach capability bringing GPS approaches closer to ILS and MLS.

PAR exists, but you may misunderstand what it is: it is a controller staring at a radar scope and issuing pilots instructions. It's stressful for pilots and controllers and very time consuming. Outside of military facilities you would be hard pressed to find a place to practice a PAR these days, at least in my experience.

In order of precision, high to low:

MLS
GPS with GBAS (uncommon)
ILS
GPS with WAAS (common, aka LPV)
PAR

In order of (estimated) total cost, high to low:

MLS (very expensive install + unique approach design + maintenance)
PAR (relatively cheap install + costly workforce; educated guess on my part, could be cheaper than ILS?)
ILS (expensive? install + simple approach design + maintenance)
GPS with * (no install, simple approach design, no obvious maintenance)


What are the names of these aircraft? Part.2

The last one is an Antinov AN-2

(source)

The first one could be the Gee Bee Y Sportster

(source)


What happens if I don't remove the "remove before flight" pad before flight?

As Ratchet Freak says, it's going to blow away or cause the engine to fail. Latter might happen if it sits tight enough that it doesn't get blown away before overpressure develops in the engine.
Not a good thing, damage may happen.

My guess most likely outcome is that it will be blown back, possibly colliding with parts of the aircraft (and thus causing damage) or hitting the hangar wall or whatever else is behind the aircraft with some speed (unless there's a lot of clear area, in which case it'd flutter to the ground), if it's not overfastened.

And to be complete, it's a cover to prevent things from getting into the engine while the aircraft is parked. Dust, animals, anything.
There will be others on the air intakes as well.


What was the first monoplane airliner with a full cantilever wing (no struts)?

I nominate the Junkers F.13. All metal, transport, and monoplane.

  It was the world's first all-metal passenger aircraft and Junkers' first commercial aircraft.

First flight was June 25, 1919. 322 were built for various military and civilian operators.

(Source)


EDIT: I'll add this ahead of the answer because it will necessarily come up: This answer is based on the model described by Prandtl, which is only that: A model, a simplified description for what happens that works to explain some phenomena. There is some disagreement about this model, so a separate explanation using a differen theory might help. The problem is that an explanation with pressure differences doesn't help much here, at least I wouldn't know how to answer the question without working with Helmholtz/Prandtl.

Fundamentally, what we are talking about are vortex rings that are created because air is moved in some direction somewhere and not moved everywhere else. That's independent of how you move it, and fundamentally, a duct or winglet or something similar can't change that. You can look at the vortex itself as the thing that actually creates lift or thrust, so you want and need that vortex.

Then there's Helmholtz's theorems. Quick quote from that article:

Helmholtz’s first theorem:
The strength of a vortex filament is constant along its length.
Helmholtz’s second theorem:
A vortex filament cannot end in a fluid; it must extend to the
boundaries of the fluid or form a closed path.

In the case of a normal wing, the vortex ring ("closed path") consists of one side along the length of the wing, two sides trailing behind the wingtips and the fourth side is somewhat lost, or far enought away that it can mostly be ignored. The three sides that are not along the wing itself are the problem, they are what the term "induced drag" refers to. Because there is no surface at the end of the wing for the vortex to end at, it has to continue into infinity. And there is some friction involved in creating long fast-spinning vortices, so you get drag. (Any help in explaining this part more eloquently is appreciated)

Because the amount of lift/thrust that you want is given, the vortex strength isn't something that can be changed either. What can be changed, however, is the distribution/speed/radius. If the lift distribution is elliptical (see: Spitfire), the lift gradient is minimal across the wing so there is no strong and fast vortex at the end, it is gradually created along the whole wingspan and the induced drag is minimal. Winglets do something similar by forcing the vortex to go all the way around the winglet.

In the case of a propeller, the inner side of the vortex ends at the spinner or shaft, so the ring is broken and you are only left with a linear vortex, but it is still trailing infinitely into the air at the tips of the blades. You can look at a wing in the same way if you interrupt the ring at the fuselage.

In the case of a ducted fan, you have two fluid boundaries, both on the inside and on the outside, which appears to solve the problem. You can have a vortex around the blade only and no vortices trailing into infinity creating drag. The problem is that the fluid doesn't really end at the duct because the duct has a finite length. So what you get is a large vortex around the whole duct. Air is moving in at the front and out at the back, and somewhere, that air moves back to the front far away from the engine.

In the case of a ducted fan, the vortex ring is created in the place where the moving air meets the static air at the beginning and end of the duct. Instead of a very small vortex around the tip of the wing (and along the wing, to not mess up Helmholtz's theorems), you get a larger one around the whole duct.

Therefore, I wouldn't say that the duct can eliminate induced drag. The effect is fundamentally comparable to a wingtip device: It increases the inner radius of the vortex and thereby reduces the induced drag significantly. It's far more effective at that than a wingtip device, but it has to be because ducted fans are usually relatively small so the drag would otherwise be enormous.


Why don't Transport Category aircraft have a listed Vy?

Large commercial jets operate within a much wider range of weights than most GA aircraft do, and since Vy varies with weight, it wouldn't make sense to publish "a" single Vy speed for them. The crew can get a best rate or best angle of climb speed from the FMC (which "knows" the current weight of the aircraft, based on current fuel & an entered Zero Fuel Weight).

From an empty aircraft with minimum fuel to a loaded aircraft with max fuel, the weight probably won't quite double for most commercial jet aircraft, but the one might be 170% or more of the other. With that much range, any single Vy you publish would be way far off in a lot of cases. On a GA aircraft, without an FMC and operating in a much narrower weight range, publishing a single speed makes much more sense as the delta between published and actual becomes smaller and the consequence of being a couple knots off is probably slight.