Is this a Janet Airlines 737 at Area 51? I was looking at the satellite image of area 51 on google earth and i noticed an airplane that was taxiing alone on area 51 at 37°14′0″N 115°48′30″W or (R-4808N) could this be a Janet airlines Boeing 737 from Las Vegas that carries the government workers to and from the base??

Probably yes.

Janet Airlines operates the Boeing 737-600 (and some Beechcraft turboprops), which has a wingspan of $ 34.32 \, \mathrm{m} $ and a total length of $ 31.24 \, \mathrm{m} $. I measured the size of the aircraft using the Google Maps distance tool:

The dimensions of $ \sim 34 \, \mathrm{m} $ span and $ \sim 30 \, \mathrm{m} $ length match (within the accuracy of the Google Maps image) the dimensions of the 737-600. The white fuselage paint also matches the Janet airlines aircraft:

(image source: Wikimedia)

Most civilian aircraft are painted white of course, but military aircraft are typically not. The red stripe is not visible from above, so it is impossible to say for sure, but since I don't expect many other white 737-600s to fly to Area 51, I think it is a fair bet to say this is indeed a Janet airlines aircraft.


What are good resources for learning more about communications? As title says, which book/web site/etc.. are available for learning proper communication (for Private Pilot License)?

Phraseology is standardized by the ICAO (but countries can notify differences to the standard) in Annex 10 and other documents. The ICAO quick reference guide presents phraseology examples for various situations (taxi, approach, emergency,...). If you are interested in recommendations concerning radio communications in general (not just what directly concerns the pilot), Eurocontrol released a European Action Plan for Air Ground Communications Safety.

Many CAAs also have some form of phraseology reference manual available for free. The general procedures and the phraseology will be almost the same from one country to the next, but variations do occur.

US:

The AIM has a section dedicated to radio communications which details procedures, phraseology and provides general recommendations. Communication examples illustrate the general principles.
The FAA also published an order prescribing ATC procedures and phraseology (but this is a very dry read. Not where I would start)
The Instrument Procedures Handbook contains information regarding radio communication procedures specific to instrument flying (e.g. how to receive a clearance at a non-towered airport)

EU:

Eurocontrol released a guide to phraseology for GA pilots describing good communication practices, phraseology for different flight phases and aviation acronyms. It also has pictures (picture books are always better ;-) ).

UK:

The CAA release a radiotelephony manual describing the phraseology for different flight phases with examples at the end of the manual. It also describes the differences between ICAO and UK radiocommunications procedures (eg FL ONE HUNDRED instead of FL ONE ZERO ZERO).

France:

The SIA has a phraseology training manual with phraseology examples for each flight phase and for using different flight services (ATC, AFIS,...)
The official text for radiotelephony with phraseology in French and English

And many more...

Knowing the phraseology is one thing, but understanding what is being said on the radio can be quite difficult. If you want to practice listening to and understanding radio exchanges, you can find ATC recordings on YouTube or go to LiveATC for ATC communications from all over the world.


Do some modern VORs not spin? Today in Ground School we learned about radio navigation. I read here that the rotating part of the VOR rotates at 1,800 RPM (wow! Is it an electric motor that spins it?)

We know that modern Active Electronically Scanned Array radars are able to send signals in different directions without physical moving but instead steering the signal electronically (by selectively delaying some of the signals precisely).

Do some modern VORs implement a similar technology and use this to rotate the signal 360 degrees instead of physically spinning?

There are no spinning parts in the VOR.

It typically uses 60 antennae in a phased antenna array to steer the beam in a rotating sweep.

The VOR transmits a constant omnidirectional signal.  The phase of the secondary sweeping directional beam is varied in time such that it is out of phase with the constant signal by the same number of degrees from North.  The receiver measures the phase difference between the constant and sweeping signals to determine its bearing from the transmitter.


Why do pilot and GPWS approach callouts say “minimums” instead of “minima”? A safe instrument approach requires a number of callouts along the way; two of the most important come fairly late in the approach, first to alert the pilot flying that the aircraft is approaching the minimum descent altitude (MDA) for that approach, and then when the aircraft actually reaches the MDA (these callouts were traditionally made by the pilot monitoring, but are now usually made by the aircraft’s GPWS).  At this point, if the pilots have the runway environment clearly and consistently in sight, they can continue and land; otherwise, an immediate missed approach is mandatory.

These callouts are typically annunciated in plural form, as, respectively, “approaching minimums” and “minimums”; however, the plural of “minimum” is not “minimums”, but, rather, “minima”, which is also shorter and takes less time to say than “minimums” (and good time management is one of the many many things that are critical during an instrument approach, especially one in low visibility or over or near obstructed terrain), so why do these pilot and GPWS callouts typically use the longer and ungrammatical “minimums”?

Minimums is an acceptable plural of Minimum (along with minima).

As for why its used as a call out is likely because it is the preferred pluralization used by the FAA and in my experience the term generally used when talking about "approach minimums" or "weather minimums".

Its worth noting that the FAA uses both minima and minimums in their handbook.


Is sustained inverted flight possible with any of today's commercial jet aircraft? After viewing the movie " Flight", I was wondering if extended inverted flight was possible with any of the current larger commercial jet aircraft?

Theoretically, it is possible to fly an aircraft upside down. Good examples are the barrel roll done by Alvin "Tex" Johnson in Dash-80 (the predecessor of Boeing 707) and the actions of Pilot Flying James Tucker during the hijacking of Federal Express 705. However, the question is whether the maneuver can be sustained for and reasonable periods of time.

In this matter, the statement of Boeing (manufacturer of MD-80 after merger with McDonnell Douglas) is instructive:

  The MD-80 cannot sustain inverted flight,...The MD-80, as with all commercial airliners, was designed to fly upright. Commercial airliners are only tested and certified for upright flight.

The pilots of Alaska Airlines Flight 261, a MD-83, tried to fly their aircraft upside down for recovery, but were unsuccessful.


Could passengers realize a possible emergency? First, to clarify, I'm not looking for nightmare stories here. I'm not curious about the fears of passengers but rather about what's actually noticeable for them. It's pretty clear that passengers not flying too often tend to be afraid during turbulence. But, I suppose, very few of them ever experienced a stall or similar.

Now, reading about crashes like the one of AF447 where a pilot only very late in the emergency situation re-enters the cockpit, I'm curious about why that is. I've never been on a plane during a stall, let alone an airliner. Don't passengers (and thus a pilot outside the cockpit) experience a stall as something very unusual, dramatic event? As another example, the crash of 4U9525 which was, as I understand it, a very "common descent": could a passenger even notice a difference between the upcoming crash and, say, an emergency landing at a close airport that the pilot just didn't have the time to explain beforehand?

Given "weird feelings" during flights, often related to turbulence which is not at all dangerous -- can a passenger "feel" the difference between those, a controlled flight into terrain, and an imminent crash?

Update

I disagree with closing this questions as a duplicate of What things can a passenger look out for, to indicate an emergency?. I was not looking for how passengers could intercept with flight management. Let's make it more concrete with the AF447 example then:

According to Wikipedia, about half a minute after the problem of wrong speed indication occurred, the aircraft went into stall. Another three minutes later the now returned pilot realized the stall only after he was made aware of the PF pulling up the whole time. Given this example, does a stall with an A330 feel so much "normal" that even a highly experienced pilot couldn't "feel" the missing lift? Will the passengers have thought the flight was still normal at this point?

One of the survivors (a passenger) of Air Florida Flight 90 was a Private Pilot and

  ...Stiley, a pilot himself, said he realized that something was wrong as the plane headed down the runway. He said there was still snow and slush on the wings and he remembered wishing he could get off the plane.

source


Where does the MiG-29 store fuel? How does the MiG-29 fuel system work? Like, where does it store around 300 cubic feet of fuel?

Also, which fuel does it use? Is JP4 preferable?

Like every plane, the MiG-29 stores its fuel in fuel tanks ;)

On a more serious manner:

Generally speaking, there are 6 internal fuel tanks: 4 distributed around the fuselage and 1 in each wing.

Later versions (namely the SMT) have larger internal fuel capacity thanks to the enlarged spine.

The exact locations of these tanks can be seen in this cutaway (src): 63, 72, 93, 107, 187.

In addition to these, the 29 can also carry 3 (1 in the very early versions) jettisonable external fuel tanks.


Which book should I study to learning flying in Australia? I'm interested in buying a text book about learning to fly so that I'll have some basic knowledge when I begin lessons.

Someone recommended the Airplane Flying Handbook (FAA), but I was wondering if there's an equivalent Australian text and whether it's worth getting?

CASA (the Civil Aviation Safety Authority) has a number of resources that might be of interest, in fact a lot of their safety publications and videos are as good as (or better than) the FAA equivalents. As best I can tell they don't have anything equivalent to the textbook-level Airplane Flying Handbook or Instrument Procedures Handbook from the FAA though.

You can find references to the FAA handbooks in some of CASA's CAAPs - for example, the Night VFR Rating information references the Airplane Flying Handbook's section on Night Operations) - so clearly they consider at least some of the information broadly transferrable.

Like Farhan mentioned the operating principles, maneuvers, etc. are going to be largely the same because the plane doesn't care what country it's in. It's the specific regulations (and regulatory citations), airspace design specifics, etc. that will vary but if you're aware of that you can easily pick out the parts that you should pay attention to versus the parts you'll need to go and cross-check in an appropriate Australian reference like the Part 61 Manual of Standards for flight training / practical test requirements.


Why do SIDs include an MEA? Let's say we're flying the JORJO2 SID (1,2) out of KPWK (RBS transition). We are told "climb via the SID". Page 2 of the SID says "maintain 3000" but the MEA on page 1 is 4000.

Is there ever a time we are supposed to climb to the MEA?  Or are we to maintain the top altitude in the SID (3000) until specifically cleared higher?  I'm just not sure what the purpose of displaying the MEA is on this chart, lost comms maybe?

Yes it's for lost comm.  If you look at the MOCA you still have the required obstacle clearance.  MOCA only gives you reception within 22 NM of the NAVAID, while MEA gives reception along the route.  If this was not an RNAV procedure I'd expect your level off altitude would probably be the MEA (just my assumption!).

In this case you would maintain 3,000' until cleared higher.  If you were to lose comm you'd fly the higher of filed, assigned, MEA, or expected altitudes.


How can I determine whether or not an airport has an ATIS? Where can I find the ATIS code and frequency for an airport through a VFR chart? For example, in the case of Frankfort airport (in the attached image), I can see the AWOS frequency but I am unable to locate the ATIS code and frequency.

Actually, Im try to fill a VFR navigation log at am unable to find the information to be filled in the Airport and ATIS advisory section. My departure airport is FKR.

The frequency for and class of the ATIS is on the VFR Sectional Chart right where you have indicated. It will also be listed in the US Chart Supplement under Weather Data Sources. The ATIS Code will never be listed as it is a function of the ATIS itself. And, it changes over time.
The left side of that section of your VFR Navigation Log is meant to be filled out shortly before takeoff. The right side of that section of your VFR Navigation Log is meant to be filled out shortly before arrival. It is helpful to have the information beforehand in your preflight planning in order to make a go/no-go decision. But, it’s primary purpose is to inform the pilot of current takeoff conditions at the time of departure and arrival. At a controlled airfield, you will be required to confirm you have the most current ATIS information by relaying the ATIS Code to ATC. That ATIS code is acquired either by listening to the ATIS over the ATIS frequency, over your cell phone at the phone number given in the US Chart Supplement, or electronically. The ATIS Code changes each time the information on the ATIS is updated. For a Class D, E, or G airport, in most cases, that is once every hour around the 45-55 minute mark. It can be more frequent for a more advanced, automated digital, non-automated, or human recorded ATIS at a Class B, C or large D airfield.
By the way, many air traffic controllers I have talked to have said that they must hear the ATIS Code either at the beginning, right after your tail number, or at the end, as the last piece of information of your initial transmission/radio call. But, I do not have any citations or references for this. Maybe another poster can provide one.


May a helicopter fly at night with only strobe lights? I thought that all aircraft flying at night needed red/green/white position lights and red/white anti collision flashing beacons.

I observed a helicopter flying over houses with only its strobe lights. Is that allowed?

In the US FAR §91.209   Aircraft lights. applies

No person may:
(a) During the period from sunset to sunrise… (1) Operate an aircraft
unless it has lighted position lights;
…
(b) Operate an aircraft that is equipped with an anticollision light
system, unless it has lighted anticollision lights.

There are no exceptions. A couple of thoughts though. It can be pretty dark on the ground and still not be after sunset. I live in the shadow of a mountain and the sun goes down at my house 15 minutes before sunset.
It is possible that they just forgot. Most pilots who have strobes turn them on all the time (an exception would be in clouds or fog) so they would be on.
It is also possible that they were on, but because of the position of the helicopter, you just didn’t see them.
The beacon (referred to in the FAR as anti-collision light system) does not have to be just red. Lots of them are red in back and white in front, so you may have seen just the forward facing light.
This StackExchange Post has more details on lighting.


Was there an incident when Airbus autopilot wasn't letting the airplane land? I'm trying to track down a story about an incident involving an Airbus airplane my father told me about 25 years ago, when he was working at a Boeing supplier.

Reportedly, what happened was the airplane's autopilot was set to bring them in to a certain airport, and the pilots noticed that it was descending too early.  So, they took over the controls, lined up manually, and at about a hundred feet up, the autopilot wouldn't let them descend further.  So, they did a go-around, tried the approach again, and the same thing happened.  At this point, they diverted to another airport and landed without incident.  Turned out that the airplane's database had an incorrect position for their destination: the plane thought they were overshooting the runway, and wouldn't let them perform what it saw was an off-airport landing.

Was this based on an actual incident, or just one of the "Airbus airplanes don't let the pilot fly" stories circulating among Airbus competitors?

I believe this is a hoax1. I've read through several documents describing the protections provided by Airbus flight laws (this is not autopilot; autopilot is a separate layer on top of it) and have never seen any mention of any kind of ground proximity protection. Only standard (E)GPWS which yells "terrain, pull up".

Update: Of course now there is EGPWS that gets aircraft position from GPS and can yell "terrain, pull up" when there is no airport ahead, but 25 years ago there was only GPWS based on radar altimeter which didn't know anything about position and would switch to simply read out2 the radar altimeter value whenever gear (and maybe also flaps; not sure here) was extended.

1Might have been even attempt at FUD against the then novel technology.

2That is say "one thousand", "five hundred", "two hundred", "one hundred", "fifty", "forty", "thirty", "twenty", "retard"3 (and "ten" or "five" when it stops saying "retard" and the wheels are not on the ground yet). This is useful during approach so the pilot can concentrate less on the instruments and more on outside reference and in the final phase to help judge when flare should be initiated. It will also warn "sink rate" when the sink rate is excessive (more than -1000 ft/min, the stabilized approach criteria).

3At 15 or so feet, if the thrust levers are not in idle gate, the Airbus system starts announcing "retard" and keeps announcing it until the thrust levers are placed in the idle gate (or reverse). This is specific to Airbus. I believe it can also announce "minimums" when approach minima are configured in the flight management system.


Does an Airbus A320 Navigation Display depict constraints for flightplans other than the primary? When any other flightplan (Missed Approach, Alternate, Temporary, Secondary) except the Primary flightplan is depicted on the ND in an Airbus A320 and the CSTR (constraint) button is pressed on the EFIS, will constraints for both flightplans be displayed on the ND?

No, just the active flight plan.

Those constraints are part of the pseudo-waypoints, which are predictions that are only displayed for the active flight plan.

  The system calculates various predictions for the active flight plan and updates them continually
  during flight (...) The MCDU and the ND show these predictions, each of which is based on specific assumptions.

  (A320 FCOM)


How were astronomical observations performed from Concorde? In addition to passenger flight and charter flight, Concorde has been used for astronomical observations, including the longest solar eclipse observation on 30th June 1973(PDF) and observation of Halley's Comet on April 1986.

How was Concorde modified for astronomical observations?
How is safety ensured with equipment installed when flying at supersonic speed and at 60,000 feet?

The Concorde was first used for observing solar eclipse in 1973. The aircraft used was Concorde 001, piloted by André Turcat with a scientific team of 8 people from US, UK and France.

The main reason for using Concorde was that the eclipse can be observed above the clouds for far longer than on ground by literally 'chasing the moon'. Multiple instruments were used for observing the eclipse.

Institut Astrophysique de Paris used cameras to capture images of the eclipse using a telescope mounted on anti-vibration mounts, which looked out of the aircraft through one of five silica quartz windows installed in the Concorde's roof. The equipment is shown in the image below:

Source: xjubier.free.fr

Queen Mary College's InSb Far-Infrared Detector experiment consisted of an interferometer that used a tracking mirror to view the solar eclipse via a quartz window fitted into the roof of the cabin, as shown in this image.

Source: jcgl.orpheusweb.co.uk

The dark opening in the roof holds the quartz window of the cabin, which looks like this:

Source: xjubier.free.fr

This was the most important (structural) modification made in the Concorde (BAC was supposed to provide Concorde 002 for this flight, but they backed out when they realized that some holes were to be made in the roof).

Los Alamos Scientific Laboratory (LASL, later to become Los Alamos National
Laboratory) used a specially-designed 3-inch telescope which looked out of the
aircraft through a silica quartz windows installed in the Concorde's roof. One objective of the research was to look for oscillations in the sun's corona that occurred on a time scale of about five minutes (the eclipse was visible for ~74 minutes from Concorde).

The instruments were checked both in ground and air before the experiment.

Before installation of the instruments on the aircraft, they were tested on a low speed trolley, perhaps to check its sensitivity to movement.
After the ground test, they were installed on the aircraft and connected to the aircraft power system and checked.
Before the actual experiment, the aircraft were flight tested at supersonic speed with the instruments on board.

The Concorde was chartered for viewing Halley's Comet in 1986 and for viewing solar eclipse in 1999. These were chartered sightseeing flights (using unmodified aircraft), not scientific ones.


How to manage anxiety just before flying? I am new to aviation and flying.
I have a one hour trip that is making me anxious and sleepless.

How can I manage the fear and is it safe or just like the news we hear on news?

It is normal to have anxiety when experiencing something new.  These "butterflies" of the stomach are your body's reaction to your minds confusion over a new situation.

This is where training and mental discipline are key.  Rationalize what is making you uncomfortable and focus on your task.

Looking down at my landing gear while flying along at 2000 feet somehow made me more nervous, so I learned to focus on the horizon and to calm down.

Put what is bothering you aside as best you can.  With experience, your mind will differentiate and sort out what should be making you nervous (losing a wing), from what should not.  Then your body will not react (by being nervous) to normal aspects of flying (departing, cruising, landing).  Enjoy the view!


Is there a formula to compute the elevator angle to stabilize takeoff? I'm building a ground effect vehicle, but I'm failing to stabilize the lift-off. At a certain speed, the lift force is equal to the weight force, so the vehicle lifts off. But this implements a change in angle of attack, so also an uncontrolled change in lift, as can be seen in this video.

I know that I can solve this with an elevator that can oppose the change in angle of attack. Now I'm searching for an equation to calculate the elevator angle to get a stabile and controllable lift off.

You need more than the correct elevator incidence. Natural longitudinal stability works by distributing lift over the flow direction such that forward surfaces create proportionally more lift than rear surfaces.

Now it is important to know that only pure supersonic lift will be evenly distributed over the chord length of a wing. In subsonic flow the center of lift is at 25% (and even less for wings of small aspect ratio), so you now need to place the center of gravity such that it will be ahead of the 25% chord line of the sum of all lifting surfaces. To distribute lift for this forward center of gravity location, the incidence of the elevator needs to be several degrees smaller that that of the wing. Adjust incidences (say 5° for the wing and 0° for the tail), and then trim the center of gravity by adding ballast or shifting masses to make the aircraft fly straight.

Since airfoil camber shifts the incidence of zero lift to more negative values, you can alternatively use a cambered airfoil for the wing (say, at now 2°) and use a symmetric airfoil for the elevator at again 0° incidence.


How large and heavy is the B737's built-in stair? Some version of B737 have built in stair, which allows passengers boarding and exit without jet bridge or stair car.

How much do the stair systems weigh? And how much volume do they occupy?

A number of 737s are fitted with forward airstairs (and aft ones too). The Boeing Airplane Planning Document gives the airstairs opening as 0.41 X 1.12m, while the airstairs can be folded to less than 2.5m length. This should give the volume occupied by the airstairs.

Image from Boeing 737 Airplane Characteristics for Airport Planning document.

According to an article in aviationpros, the total system weighs in around 200 lbs:

  Aircraft such as the DC9, MD80, MD90, and 737 aircraft have had a long enough history that many of them were built with the forward passenger air stair assembly. Many aircraft were also converted to non-airstair versions Ñ a 200+ lb. weight savings for the operator.


How do STOVL and V/STOL aircraft differ? Wikipedia's page for STOVL begins with

  A short take-off and vertical landing aircraft (STOVL aircraft) is a fixed-wing aircraft that is able to take off from a short runway (or take off vertically if it does not have a heavy payload) and land vertically (i.e. with no runway).

while V/STOL is

  A vertical and/or short take-off and landing (V/STOL) aircraft is an airplane able to take-off or land vertically or on short runways. Vertical takeoff and landing (VTOL) aircraft are a subset of V/STOL craft that do not require runways at all. Generally, a V/STOL aircraft needs to be able to hover.

On both pages, it is stated that the respective type should not be confused with the opposite one.

Essentially, it says STOVL is not the same as V/STOL and vice versa.

However I have trouble understanding where the differences lie between them.

I was about to clear it up on my mind when I thought STOVL definitely requires some (short) distance for the aircraft to clear before taking-off, while V/STOL aircraft are simply able to start hovering in order to take off. But apparently, it's possible for STOVL aircraft to do so if they don't have heavy payload.

What am I missing here? Both are supposed to be able to land vertically so I suppose there's either a difference on the take-off or if not, there are differences on the wing structure/geometry of each type of aircraft.

To put it simply, it's about the ability to take of vertically at any mass:

V/STOL aircraft can take off fully loaded (max. operational weight).

STOVL aircraft does not have sufficient engine thrust to take off vertically at any weight, and at higher T/O weights it must have some lift from wings to assist the T/O. It may be able take off vertically at less than max. T/O weight.


How does early rotation increase the likelihood of a tail strike at take off? This question indicates that an early rotation can cause a tail strike. What are the (pre-)flight dynamics that would cause this to happen vs what happens when rotating at the proper time?

When preparing for a flight, pilots will calculate many things, including their rotation speed. This is the speed in their takeoff roll at which they will start to pitch up, and hopefully the plane lifts off the ground. The rotation speed is dependent on many things such as temperature, altitude, and aircraft weight.

My answer here discusses the lift calculations in relation to rotation. That question covered the importance of speed related to weight. More speed is needed to create the lift to take off with a higher weight.

When the airplane rotates, it increases the angle of attack of the wing, which increases the lift coefficient (if the wing does not stall). The pilots will pitch up at a certain rate, and they do not stop until they reach a climbout attitude higher than what is possible when the main gear is still on the ground (though this may depend on company policy). They count on the plane acheiving enough lift during rotation to leave the ground so that they pass that maximum pitch while in the air.

If pilots underestimate their weight, they will calculate a lower speed than is necessary to provide the lift for takeoff. This means that when they rotate, the plane doesn't have enough airspeed yet to create enough lift to take off. So instead of leaving the ground before fully pitching up, the tail strikes the runway.

It may seem like an easy mistake to make, but thousands of pilots do it every day without a problem.


Why does the Canadair Regional Jet still use CRT screens? All the CRJ aircraft from the 100 up through the new 1000 use the antiquated CRT technology for the main primary and secondary displays as well as the ED1 and ED2 displays.

Aren't flat screens a more modern, cheaper and reliable technology? Why aren't there flat screen retrofit units for the older aircraft or flat screens in the newer aircraft?

This is just an educated guess, but it was too much info for comments. Maybe someone can come up with a specific answer, but it seems it's probably a certification delay. The CRJ's all use the Rockwell Collins Pro Line 4 avionics suite, which uses CRT's. In 2000 Rockwell Collins introduced the Pro Line 21 suite which uses LCD screens. They have been slowly introducing PL21 retrofits for aircraft with PL4 as they receive STC's. The Falcon 50 and 2000 began getting retrofits in 2008, followed by Beechjet 400A in 2009, King Airs in 2010, Learjet 60 and Gulfstream G100 in 2012, Piaggio Avanti in 2013, then Hawker 800 and Challenger 300 & 605 in 2014.1

My presumption is that the CRJ's have a type cert with the PL4 and they very well may be working on getting a cert with the PL21 or the newer Pro Line Fusion suite. It will certainly become increasingly difficult to find replacement CRT's as there a only a couple of companies still manufacturing them. It seems just swapping display types is not feasible with the PL4 system. The PL21 system was designed to be more flexible so it's easier to integrate improvements in technology.2

1 These dates might be wrong. I'm finding different dates from different sources. For example, Falcons began getting them in the US in 2006 but it didn't receive EASA certification until 2014.

2 http://jetadvisors.com/rockwell-collins-proline-21-avionics/


What causes a "BATT DISCHARGE" CAS message on the Phenom 100E? In the Phenom100 POH the descriptions for the "BATT DISCHARGE" CAS message is "During a normal system operation, at least one battery is discharging."

I'm a bit confused as to what exactly does normal operation mean.

Do I get the message as soon as I turn on both batteries ?
Does it show during the starting sequence if the GPU or other StarterGenerator is connected ?

And most important where can I find this information? I have not been able to find it in the POH or any other manual

I've also found this video on youtube but it seams to be from an older version and while it is showing the message during the first engine start it doesn't show it for the second when BATT1 should be discharging for sure because it's used to power the DC buses. Moreover this video contradicts what I know for sure from the EV and the simulator.

I've also checked the K-codes for this particular CAS message and it has none

I am not into the Phenom 100E nor the avionics.
However, me and many others think that there is not much space for interpretation on this message.
In the G1000 handbook of the Phenom 100, on page 129 in the section "CAS Messages > Caution Messages", it says:

BATT DISCHARGE Battery discharging under normal operation

Source

Source (Page 122)
This is the electrical status page as shown on the G1000 of the Phenom 100E. I marked the batteries yellow and all parts actively generating electricity and affecting load of the batteries in red.
When will BATT DISCHARGE pop up?
BATT DISCHARGE will pop up, if the load on the batteries is higher than the charge. This applies in following situations:

Master is on and systems are consuming electricity from the batteries but no engine and generator is on and no GPU is connected to the aircraft.
If the message pops up during flight, in which GEN 1 and GEN 2 usually charge the batteries, there is a problem with the generators. Additionally there can be displayed an ELEC EMERGENCY warning on the CAS.

What we see in the video

Start of engine Nr. 2 When he starts the first engine, we can see three CAS-Messages: BATT DISCHARGE, SHED BUS OFF (definition of SHED BUS below) and GPU CONNECTED. The engines on a Phenom are cranked by electricity, not by pressure air, so the BATT DISCHARGE makes sense first. However, the GPU is connected. Now, many things could happen here. Maybe an engine start is using lots of power, even more than the GPU can deliver.

After start of Nr. 2 After the start (~ 1:32), we can see on the status page, that the GPU was disconnected. The Generator of ENG 2 is already running. On the CAS there is still the BATT DISCHARGE and GPU CONNECTED to see. They disappear at the same time. This is probably because of some delay in the CAS-System. That means the battery is discharging, even though the GPU is connected (~ 0:55). It could be because of a weak GPU.

Start of engine Nr. 1 (~ 1:58) When the second engine gets cranked up, we can see, that the GPU was removed shortly after start of engine Nr. 2. However, there is no BATT DISCHARGE caution message anymore. Now engine Nr. 2 charges the battery. Maybe the generator is stronger than the GPU before. While starting Nr. 1, the SHED BUS is off again.

Unfortunately the video doesn't show, when engine Nr. 1 has started and is stabilized. It would be interesting.
Personal conclusion
As already said, I am not a pilot nor an engineer and only have the knowledge I have self-taught. On this knowledge-basis, I would say following looks most logic for me:
The GPU delivers only a small amount of electricity to the plane. It can't balance the load of the battery. I don't know if this is possible, but looks logic for me. After engine start, the generators of engine Nr. 2 provide the aircraft with lots of power, enough to charge the battery and to start the other engine.
The theory of a GPU, providing only a small amount of electricity would be supported by how the SHED BUS works, below. The EDL disconnects the SHED BUS because the batteries are loosing power. You can see this at ~1:08 in the video in the ELEC section of the MFD. It shows: BATT 1 - 23.5V and BATT 2 - 25.8V. This is well below the normal voltage of 28V. A bit later at 1:28 we see that both batteries have dropped to ~24V and are still discharging. At ~1:30 we see the generators providing electricity and the batteries are charging again fastly. Thats also when the SHED BUS is coming on again. At 1:58 the SHED BUS is off again and the batteries are down at 22V and 25V.
So, when I look at the facts, it looks like a weak GPU for me. However, there is still one question: Why is there no BATT DISCHARGE when starting Nr. 1?
My theory is: It looks like there is some sort of delay in the CAS-System. As we have seen in the video, the GPU is already indicated to be disonnected on the MFD, but the CAS still says it is connected. Maybe the message BATT DISCHARGING hasn't appeared because of the delay. We lack the last seconds of the video, so we don't know if the message maybe appears or the generators provide electricity early enough, before appearing.
(I think this question needs more attention. It's a nice puzzle question that deserves much more upvotes.)

UPDATES

I have now found GPU values I can't confirm to be true:

GPU Limits
27V to charge
26-29V for operation
800-1000 Amps

Source

The SHED BUS

The shed bus powers non-essential aircraft systems. In the case of the phenom 100 this is things like the air conditioning, passenger power sockets and entertainment systems, the toilet and some lighting.
The shed bus is the first thing to lose power (be shed) should the aircraft not be generating enough electricity through, for example, a generator dropping offline.

From my question about the shed bus by sp1.


Why Heading Indicator is not magnetic itself and need magnetic compass? I read this while I was preparing for my knowledge test:

  The heading indicator is not direction-seeking. It is important to
  check its indication frequently and reset it with reference to the
  magnetic compass.

and I am doing this all the time during flight time.

Why don't small aircraft manufacturer make the Heading Indicator magnetic instead of gyro?

Compass readings during turns are inaccurate and sometimes display turns when you are heading straight but accelerating. As such you need something that is referenced to the airframe turning itself. This is where the gyro comes in handy. Since it's referenced to the airframe and relatively unaffected over short periods of time it gives you your heading when your compass can not. You can also "time your turns" using the turn coordinator and a stop watch should your heading indicator fail. It should be noted that a timed turn will only work if the turn remains coordinated (no slip or skid) further more most turn coordinators are set up for 2 minute turns.

The errors are as follows

  If on a northerly heading and a turn is made toward east or west, the initial indication of the compass lags or indicates a turn in the
  opposite direction. The lag diminishes as the turn progresses toward
  the east or west where there is no turning error.
  If on a southerly heading and a turn is made toward east or west, the initial indication of the compass needle will indicate a greater
  amount of turn than is actually made. This lead also diminishes as the
  turn progresses toward east or west where there is no turn error.
  If a turn is made to a northerly heading from any direction, the compass indication when approaching northerly heading leads or is
  ahead of the turn. Therefore, the roll out of the turn is made before
  the desired heading is reached. If a turn is made to a southerly
  heading from any direction, the compass indication when approaching
  southerly headings lags behind the turn. Therefore, the roll out is
  made after the desired heading is passed. The amount of lead or lag is
  maximum on north / south headings and depends upon the angle of bank
  used and the latitude of the aircraft.
  When on an east or west heading, no error is apparent while entering a turn to north or south. However, an increase in airspeed
  will cause the compass to indicate a turn toward north. A decrease in
  airspeed will cause the compass to indicate a turn toward south.

The constant need to reset it is related to gyroscopic precession.


What was the lift-to-drag ratio for WWI biplanes? I will be interested to know what was the lift-to-drag ration for a few more known WWI biplanes at take-off, cruise and landing speed; with the propeller running, stopped or non existent (tests in wind tunnels).

AE Berriman published his respected survey of Aviation in 1913. At that time drag was known as resistance, with other terms such as head resistance or drift also used. He discusses the lift:resistance ratio only with respect to aerofoil design.
It is unlikely that the l/d of the whole aircraft was ever considered quantitavely as a useful number. One might gain some idea by looking at Farnborough wind tunnel results for propeller thrust at given airspeed and RPM, and then comparing those with aircraft fitted with that propeller, but that would have been of little value in a hectic war and would not have been done. Of more use was the relative speeds of different types when given the same engine and propeller, or of a given machine when fitted with a new propeller.
Pilots would have had some idea of how far their machines would glide when the engine failed, as happened often enough, but only hazy notions of actual speeds and sink rates. They would also have struggled with the fact that the gliding speeds and angles for minimum sink rate and maximum distance were different.
With hindsight we can make guesses. Glide slopes remained well below 1:10 until the German soaring gliders of the 1920s. Airspeeds were slow, around 100 mph, so thrust and drag were not as high as might be expected today. While engines had relatively poor power-to-weight, airframes were so light they would sometimes break up under the extreme manoeuvres of combat. A steep gliding angle of say 1:4 would have required an unrealistically powerful engine to generate thrust (nominally) equal to a quarter of the gross weight, so wings were relatively large and lightly-loaded to give better lift at lower speeds.
So I'd hazard that around 1:5 to 1:8 would have been the norm. If anybody knows of a better-researched analysis, I would be delighted to be proved wrong.


How do military radars detect the type of an aircraft? How do the military air defense radars and aircraft radars detect the type of an aircraft and enemy or friendly information?

This depends on the type of radar system and its intended application. You can find a nice bit of history on it here. The early radars could not tell the difference between aircraft types, any kind of movement was coordinated beforehand on the friendly side and anything that was not pre-arranged was considered foe. The early Doppler systems that resided on the DEW Line could be trigger by as little as a dense flock of birds. The early radar data from the DEW Line was processed on the SAGE system a very early (very primitive) system for coordinating a great deal of weather, radar, and flight information.

After WWII and through out the cold war era newer tech was built to solve the issue of coordination. The modern Identification Friend Or Foe system that is now in use provides at least some way to pick apart radar targets.

With the advent of modern computer processing and the ability to analyze radar returns beyond staring at a scope it is possible to determine (with great certainty) the make of an aircraft by its radar signature (and in some cases thermal signature). Also known as Radar Cross Section. Everything (even stealth planes) have a radar cross section and once a cross section has been identified it could be used again to check against future pings.

One could go as far as to say there is some historical precedent around this. The general idea of "if it comes from over there is one of them, if it comes from over hear its one of us" is very much how radar worked for a long time and the identification of the actual plane was less important than identifying that it was there. If an unidentified target entered a radar area and did not identify its self, over the radio, with some kind of transponder and or at a preordained time it was intercepted. Not until visual identification was made was it not longer considered a threat.

Here in the states by 2020 the civilian world will be sending speed and position data via ADS-B OUT to supplement (and potentially replace) radar returns.


What are possible causes for the flaps not deploying on a Cessna 172? I would like to seek some expert opinion on why my flaps failed to deploy when I took it to Flaps 20.

I was turning from Downwind to Base when I took flaps 20 and noticed that my speed was creeping past 80kts even at idle power. My instructor took a look outside and that’s when we realised that the flaps were still at the UP position. We tried checking the circuit breaker for Flaps and the other switches, and everything else was normal.

We came in flapless until short finals when the flaps deployed to Flaps 10 when the switch was moved to the Flaps 30 position.

We did some checks on the ground and whenever we took Flaps down, static interference could be heard. It’s as if it was timed to happen the moment the flaps are extended. No static heard when the flaps are raised.

Any expert opinion would be appreciated as I would like to really understand what I am flying. I have checked the POH and it barely says anything, even the Electrics diagrams aren’t helping me diagnose why.

I’m a student pilot with barely 20 hours flight time.

If the flap actuating motor is defective, you'll get exactly (or very close to) those symptoms, including the "interference" when the motor is operated. It could also be that the power connector to the motor was loose, damaged or corroded.


What constitutes an "emergency" in flight procedures? In reading through the more informal literature (Wikipedia, FAA PDFs, Av.SE), I often come across a caveat to standard flight rules and procedures: "unless an emergency exists". The intention is obvious; ATC is going to prioritize helping an aircraft that encounters a situation that simply cannot be ignored. However, most such resources don't go into specifics about what kind of situations constitute an "emergency". There are obvious emergency scenarios, like a "dead stick", and there are obvious non-emergencies like "I have to be on the ground by 5:00 to beat traffic home". Then there are grey areas like "I fought a headwind the whole way here, I'm low on gas and now my home field is IFR and won't grant me SVFR. I might make it to my alternate even further upwind that's clear, but I really think it's best to set down here even if I can't see the far end of the runway".

So, the questions:

What kinds of things constitute a genuine emergency, and what will get a pilot laughed at by ATC (or worse)? Where's the line?
Is ATC allowed to judge what is or is not an actual emergency, or must they prioritize any aircraft declaring one?
Does fault or blame matter at the time the emergency is declared? Will ATC de-prioritize a situation that is obviously the pilot's fault, like flying into the only cloud for 50 miles in any direction?
Is there anything you still can't do as PIC in an emergency situation? Apparently in an emergency you can do a lot of things that would get your license pulled in any other scenario, like violating separation minimums, entering airspace that's normally off-limits like R-zones and Class A space, running on instruments without a rating, etc. While these things are still dangerous, it is apparently the pilot's prerogative to resolve the emergency however he can. Is there anything a plane declaring an emergency still must do other than fly the plane, or conversely something he still cannot do like get too close to Air Force One?
After declaring an emergency in flight, what should be done after the plane's back on the ground (hopefully safely)?

There is a really good explanation of emergency situation over at the SkyBrary:

An emergency situation is one in which the safety of the aircraft or of persons on board or on the ground is endangered for any reason.
An abnormal situation is one in which it is no longer possiible to continue the flight using normal procedures but the safety of the aircraft or persons on board or on the ground is not in danger.
Emergency or abnormal situations may develop as a result of one or more factors within or outside an aircraft, for example:

Fire on board the aircraft;
Aircraft component failure or malfunction (e.g. engine failure, landing gear malfunction or loss of pressurisation);
Shortage of fuel (or other essential consumable substance);
Flight crew uncertain of position;
Worsening weather;
Pilot incapacitation (e.g. as a result of illness);
Aircraft damage (e.g. as a result of collision, bird strike or extreme weather;
Illegal activity (e.g. bomb-threat, wilful damage or hi-jacking).

So in short, anything that puts the flight in danger can be considered an emergency.

Is ATC allowed to judge what is or is not an actual emergency, or must they prioritize any aircraft declaring one?

If the pilot declares emergency, ATC will provide assistance and support to the flight without judging whether it is an actual emergency or not. ATC cannot know in most cases, nor are they really required to analyse the situation to come to that conclusion. Their whole responsibility is to ensure the flight receives all required information and support to either end the abnormal/emergency situation or land at a suitable airport.

Does fault or blame matter at the time the emergency is declared? Will ATC de-prioritize a situation that is obviously the pilot's fault, like flying into the only cloud for 50 miles in any direction?

No, they will not de-prioritize based on the type of emergency. Even if a pilot flew VFR into IMC conditions, he is still in a life-threatening situation from which he needs to recover, so assigning blame or guilt is not helpful here, nor would that be the ATC's job. This is the Civil Aviation Authorities' responsibility, once the flight is back in safe conditions. ATC may file a report, though, but not during the emergency, but as an aftermath.

Is there anything you still can't do as PIC in an emergency situation? Apparently in an emergency you can do a lot of things that would get your license pulled in any other scenario, like violating separation minimums, entering airspace that's normally off-limits like R-zones and Class A space, running on instruments without a rating, etc. While these things are still dangerous, it is apparently the pilot's prerogative to resolve the emergency however he can. Is there anything a plane declaring an emergency still must do other than fly the plane, or conversely something he still cannot do like get too close to Air Force One?

Technically, once you have declared an emergency, you can do whatever is required to keep the flight safe and prepare for an emergency landing. If you need to enter otherwise controlled or restricted airspace, this will be made possible by ATC via coordination with adjacent units. Without knowing FAA regulations on this specifically, I would daresay that distress traffic could have priority over the Air Force One.

After declaring an emergency in flight, what should be done after the plane's back on the ground (hopefully safely)?

Unless your CAA or their respective investigative service is not already waiting for you, you should remain with your aircraft (unless being treated for medical issues and taken to a hospital) and wait for them to arrive. If in doubt, you can call the police and they will notify the relevant authorities.


What happens when you call 866-GA-SECURE in the US? I live in the US, near a fairly dangerous road, and I've called 911 a few times to report car accidents outside my home.  It's a lot like giving a PIREP - you give the necessary information and the appropriate help is dispatched.  All very simple and clean.

I've never heard of anyone calling 866-GA-SECURE.

What happens when you do?  Who do you talk to?  Who responds?  How fast is the response?  What can you expect?

OK, I did a little digging and here's what I can definitively tell you:

1-866-GA-SECURE is a joint venture between AOPA's "Airport Watch" program and the TSA.
The hotline is staffed by federal officials and can be used for reporting suspicious or unauthorized activity - e.g. the theft of an aircraft, someone prowling around on the ramp after hours, etc.
The folks answering the hotline will be able to contact local law enforcement (and being that they're federal officers making the call instead of Joe Pilot, they may get a quicker response than you would), but police dispatch isn't their primary function.

The TSA's own guidance on this hotline indicates that it shouldn't be your first resort -- they would prefer that you contact:

Airport management/operations/FBOs
Particularly at fields that are attended 24/7, and those with security or police presence, calling the folks on the field will often give the fastest response, and they should be your first call.
The TSA Hotline (1-866-GA-SECURE)
For fields which are not attended / don't have a security or police presence, this can be an effective way of getting law enforcement to the field quickly.
911 or other local law enforcement emergency numbers
In situations with immediate and potentially dangerous consequences, or ongoing criminal activity (breaking into aircraft, bypassing gate locks, etc.) calling local law enforcement's emergency number / 911 is The Right Thing To Do.

In all cases you can follow up with a call to the TSA hotline to confirm they're aware of the incident.  Whether on an initial call with an ongoing situation or a follow-up the hotline folks will want the basic 911 information (Who you are, Where you are, and What your emergency/situation is). Obviously depending on the situation they may ask for additional details - e.g. if you're reporting that a plane was stolen it would be very helpful if you could provide the registration number.

AOPA's GA Security course covers a bit more of what you may be asked for / about, and the kind of things you should be looking for when informing any of the above authorities of suspicious activity.

Who responds to your hotline call and how quickly they respond is less definitive: It will vary depending on where you are and the local resources available.  A grass strip many miles away from the closest police presence at 3 AM will obviously have a longer response time than a 24x7 attended field with a police presence on the field, no matter who you call.

Typically the first response will be airport personnel (if the field is attended) or local law enforcement (and obviously that will be the case if you're calling the airport's management/operations office or the local police directly).  Whether or not federal authorities get involved in the response would likely depend on what you're reporting.


How do you calculate trip fuel based on hourly fuel burn rates? I am working on a small personal project that uses fuel burn data about specific aircraft to calculate the total fuel required for a trip. The data looks like this:

          | 120000 kg  | 150000 kg | 180000kg
----------+------------+-----------+-----------
21,000 ft | 6250 kg/hr | 6350 kg/hr| 6450 kg/hr
22,000 ft | 6225 kg/hr | 6325 kg/hr| 6425 kg/hr
23,000 ft | 6200 kg/hr | 6300 kg/hr| 6400 kg/hr

Based on the table above, you can see that to cruise at 21,000 ft and a weight of 120,000 kg, you would burn 6250kg/hr.

The problem I am having is that in order to calculate total weight, you first need to know total fuel, which you don't have until you know the proper burn rate. What would be the proper way to calculate fuel based on this information?

This would typically be solved iteratively. You start with your mass equal to ZFW and calculate how much fuel you need based on the table:

$$ \mathrm{Fuel}_1 = \mathrm{Fuel}(m=\mathrm{ZFW}) $$

Then you add this fuel to your total weight and repeat the calculation:

$$ \mathrm{Fuel}_2 = \mathrm{Fuel}(m=(\mathrm{ZFW} + \mathrm{Fuel}_1)) $$

which will give you slightly larger result. You repeat this process until convergence, meaning

$$ \mathrm{Fuel}_{i + 1} \approx \mathrm{Fuel}_i $$

and this is your final result.


Is this scaling of aircraft size and power (at least roughly...) correct? I use to fly a very light plane, with a 100-hp engine. In order to calculate the power needed by a similar plane, but 50% larger, I reason as follows:

In general, the power required by an airplane is proportional to its weight times its speed. The weight scales with the cube of the linear dimension, so the larger plane would weigh 1.5 cubed = 3.375 times more. Since the airspeed is squared in the formula for lift, the exponent for the proportionality of lift should be 1/2.

I have now two exponents for the scaling, 3 for the weight (or mass, in this case) and 1/2 for the speed. As the weight and speed are multiplied in order to get the proportionality of the power required, I add the exponents, and the result is that the larger plane would need an engine of 1.5 ^ 3.5 = 4.13 x 100 = 413 hp.

Is this OK?

For a first order of magnitude check your result looks good.

Experience tells that the mass scales not quite with the length cubed, so an exponent between 2.3 and 2.6 gives better results. Wing area goes up with the square of the length increase, so your wing loading will become
$$\frac{m_{large}}{A_{large}} = \frac{m_{small}^{2.4}}{A_{small}^2} = 1,176\cdot\frac{m_{small}}{A_{small}}$$
This requires 8.44% higher speeds. To achieve them, thrust must go up with the square of the speed increase and power with its cube, since power is thrust times speed. Therefore, the power increases by a factor of 3.375 if the mass scales with the exponent 2.4. Power loading will now be
$$\frac{P_{large}}{A_{large}} = \frac{3.375\cdot P_{small}}{A_{small}^2} = 1,5\cdot\frac{P_{small}}{A_{small}}$$


What is the best way to align with centerline on final, rudder or slip? Like many student pilots, I consistently find myself slightly left of centerline in the last few seconds before touchdown (e.g. between crossing the threshold, through roundout and flare), despite flying a stabilized, on-course approach on Final, with no crosswind component.

My question is how to realign with centerline in those last few seconds? I've been suggested two techniques (see below), but I'm not at ease with them.

I did see the "Crosswind, crab or slip?" question, but I believe mine is different. I am wondering what is the correct technique without crosswind. Even if they have the same answer, it's not necessarily the same question, as the technique one uses MAY be different w/crosswind (or not! I don't know).

My CFI suggested imagining the centerline extending vertically into the air, and using rudder pedals to align with it as if I was 'taxiing' on that centerline. So if the plane is to the left of this imaginary centerline, apply right pedal to yaw the aircraft to the right, and vice-versa. In either case, the longitudinal axis of the aircraft is intersecting the vertical centerline at some point down the runway.

Problem is, when I do this, it doesn't feel like the plane moves towards centerline at an appreciable rate. It just feels yawed, but without any "movement" towards the side that I'm pointing to.

Alternatively, I've seen in some videos online to use the rudder pedals to align the longitudinal axis of the aircraft PARALLEL to the vertical centerline, and instead use ailerons to slip back to centerline. So if the plane is to the left of center, point the nose of the aircraft parallel to centerline, but roll aircraft to the right.

Both unnerve me a bit, but for different reasons. For the former, I'm not used to the 'crabbed' orientation so close to the ground. For the latter, I'd prefer the wings to be level so close to the ground.

Which technique is preferable?

Your method #2 is consistent with current FAA doctrine, and when practiced yields acceptable results.

Rudder for longitudinal axis alignment (parallel) with the centerline.

Aileron for drift.

Have a stable approach, and maintain vigilance of both inputs when on low final.  If you practice the technique for your entire final approach, you get extra practice time, and may master the technique faster.

FAA has a publication, On Landings I  (and also a II and III publication) which are all great at describing the technique.  Every student should have a copy for review.  FAA-8740-48  a copy is here: https://www.flyingd.net/documents/on-landings-part-i.pdf

To answer a comment...if you are left of the centerline, and there is no wind, and your approach is stable, then you need some right aileron to get your longitudinal axis over the centerline, and you will have to adjust your rudder while maneuvering, to keep the longitudinal axis aligned and at least parallel to the centerline.

Drift with aileron, alignment with rudder. Constantly modifying input to get the desired drift and alignment.

Aileron for drift.

Rudder for alignment.

Pitch for airspeed.

Power for altitude.


How can I test a COM VHF antenna? I have an older VAL 760 TSO COM radio. Twice now the radio has blown an internal radio fuse on transmit. VAL has tested and certified the radio as "Good", but advice that the cable or antenna could be faulty. How does one test that the antenna or cable is adequate? Can one use an ohm meter to check for resistance or continuity? Any other advice is appreciated. I have a newer VHF antenna. It may be a CI-101, although not positive.

Your radio shop may be able to test the SWR of the antenna working with the COM radio.  That would be my starting point.  However, sometimes problems like these are intermittent and difficult to isolate.

You can test the antenna with an ohm meter but that will not measure the impedance at transmit frequencies.  An SWR meter will.

Unfortunately, unless your other hobby is ham radio, you may not have the equipment on hand to check out transmitter operation.  But your radio shop will.

They will also have a dummy load for testing the transmitter.

I have to say that I am surprised that the unit blew a fuse.  Most aviation radios I have experience with (I am not an avionics tech only a ham) have protection against shorts or opens on the output of the transmitter, which usually shut down the power of the transmitter, for example when a high reflected signal comes back. So blowing fuses is normally extremely rare.


Why aren't the canards used as airbrakes on the Tupolev Tu-144? The Tupolev TU-144 uses retractable canards to stabilize the aircraft while starting and landing. On this picture you can see them very well:

Source: AirlineFan.com Copyright: VOLPATI

It doesn't have reverse thrust and air-brakes, and relies purely on very strong wheel brakes. Wouldn't it be possible to rotate the canards by 90° (after touchdown) in order to create a very large air-brake? I don't think it would need too many modifications to the current form of the canards.

A number of things happen when you rotate the canards by 90°, and in no way I see how these could be addressed by

  not too many modifications

1. Transient

Once you land, you need a certain amount of time to rotate the canards. During this time the canards will not produce a perfectly horizontal force, but it will have also a vertical component.
Whether this component will be upwards or downwards it will depend on the rotation direction: rotate them with the leading edge up, and you will have some upward force; downward otherwise.

In both cases this is not ideal:

an upward force will reduce the adherence of the nose wheel, reducing the steering authority
a downward force will increase the load on the wheel, increasing the chance of tire burst and increasing the required size of the strut to sustain said load.

2. Deployed Status

Let's assume for a second that the transient problem can be avoided. Now you have two large surfaces perpendicular to the airflow that create a massive amount of drag. And torque.

You need then to design a structure that is capable of:

keep the canard in place during the flight
rotate the canard by 90°
sustain the drag force during deceleration
sustain the torque during deceleration

You can reduce the torque and drag forces to be transmitted through the mounting by delaying the deployment/rotation of the canards, but that would defeat the purpose or, at the very least, severely limit the usefulness of such a system.

In conclusion, a structure that would fulfill all the listed requirements is

extremely likely to be heavier than equivalent brakes,
more likely to be prone to structural problems due to complexity,
more expensive due to maintenance,

making even less sense in an aviation application.


How many miles before the runway should an airliner put the gear down? I was watching this video of a FedEx MD-10 landing and some questions came up, of course again the unprofessional YouTube comments didn't help.

How many miles before the runway should an airliner put the gear down?
Was the aircraft in the video too close?
At which distance does radio altimeter warn the pilots?
Is the following YouTube comment accurate?

  This was FedEx flight 1356 and I can tell you what happened. During approach there was an anomaly on the left slat and it was being watched. Also during approach engine no.1 was heating up to unacceptable levels and because of all of this the gear wasn't lowered right away. It was only due to TCAS and the alarms on board that it was noticed as the aircraft was approaching it's minimums. Upon landing the crew was reprimanded for not following proper procedure and was suspended with pay.

To answer the last part of your question, as ratchet freak said, the TCAS doesn't warn the pilot when he should deploy landing gear. However, the ground proximity warning system/terrain avoidance and warning system (GPWS/TAWS) does. GPWS Mode 4A is "Unsafe Terrain Clearance With Landing Gear Not Down".

If the plane is less than 700ft (based on the radio altimeter's measure) high and under mach .35, there is an aural alert in the cockpit saying "Too low - gear". The message is repeated until the situation is corrected.

So the warning is based on the height and speed of the aircraft. Not on its distance to the airport.


Who operates the hoist in a Coast Guard helicopter SAR team? Could you tell me who operates the hoist in the Coast Guard helicopter SAR teams?

Is it the A&P technician(Flight mechanic) or the Rescue swimmer(winchman)?

I'm interested to procedures from around the world, in particular inthe US, UK and Canada, but not limited to them.

who operates the hoist in the Coast Guard helicopter SAR teams?

This depends on country and other factors, perhaps aircraft type etc.

In general, the winchman descends on the end of the winch cable and does not operate the winch.

In the UK, helicopter search and rescue were, until recently, mostly provided by the RAF. HM Coastguard HMCG (now part of Maritime and CoastGuard Agency - MCA)  operate SAR helicopters too and will mostly take over the SAR role.

  The standard SAR crew is made up of four members: two pilots, one of whom is the aircraft captain, a radar operator who acts as the winch operator at the rescue scene and a winchman, normally trained to paramedic standard, who will supply immediate first-aid and recovery services at the rescue site.

From RAF Sea King

Sometimes the role is taken by aircrew normally responsible for loading/unloading:

  If you are part of aircrew, you would be responsible for loading and unloading aircraft payloads, ... You would also take on extra duties according to the aircraft type and its operational role. For example, ... you might train as a winch operator for search-and-rescue operations.

From RAF non-commissioned aircrew

Other References

Search and Rescue Training
Working with Search and Rescue Helicopters
Coastguard search and rescue helicopter programme


What bank angle creates the least energy loss in an emergency engine out 180 degree turn? A situation we all hope to never have:  engine quits at a low distance AGL.

What bank angle will produce the least altitude loss for a 180 degree turn?
Is this common for all aircraft?

Readings have shown the elevator/wing to be more efficient at turning the aircraft
than the rudder alone.

It would seem better not to try to hold altitude on the turn, but one still must avoid stalling
the wing.  Airspeed is also a factor in gliding efficiency.

What is the best way to turn 180 degrees with least loss of altitude?

Some good references provided.  Curious about rudder technique in a steeper bank. At 45 degrees, rudder is pitching nose down some, but should be there to "follow" the wing around the turn (lowest drag).  Some elevator, some rudder to swing the tail through the yaw plane, giving up some altitude, so as not to load the wing as much (like an emergency descent)?

Asked and answered, since a any plane without a functioning engine is basicly a glider:
What is the optimal bank angle to accomplish a given turn in a glide?

Assuming the question refers to an engine failure after takeoff, there is a lot more to the stunt than just turning with the least amount of altitude loss. In any case, before attempting "the impossible turn" you must be above the safe altitude for the maneuver. If you have not yet reached safe altitude, you make an emergency landing in the front sector. The safe altitude varies heavily with different plane makes and models, but for example a C 172 needs about 500ft and rather aggressive (yet skilfull) handling according to tests made for AOPA Pilot 2002 july article.

To make an efficient 45 degree turn while maintaining a steady speed is not exctly a walk in the park if you have just lost an engine. Attempts to return to the runway after an engine failure during initial climb have a strong tendency to end in tragedy.


What is the Beggs/Mueller emergency spin recovery technique? I've always used PARE for spin recovery:

  Power to idle
  Ailerons neutral
  Rudder opposite the spin until rotation stops
  Elevator forward to break the stall

What is Beggs/Mueller emergency spin recovery, and why does it work?
Does it work in any aircraft?

The Beggs/Mueller technique is:

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

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

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

Why rudder against spin direction?

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

Why elevator forward (Back in inverted spin)?

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

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

Why engine to idle?

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


What does ® mean in the Chart Supplement (A/FD)? What does the circled r: ® mean in the Chart Supplement (A/FD)? You can see it here to the left of SOCAL APP/DEP CON:

According to the Chart Supplement (formerly the A/FD) legend:

  APP CON—Approach Control. The symbol ® indicates radar approach
  control

And:

  DEP CON—Departure Control. The symbol  ®  indicates radar departure
  control.

The FAA has different approach facilities classifications, a TRACON has radar but others don't. So you should see this symbol when the approach/departure services are provided by a TRACON or other radar facility.


Can a certified mechanic ground my airplane? The courtesy (under-wing) lighting and the rear seat overhead map light were on the same switch. I didn't like having the bright outside light on while my passenger read his magazine, so I separated the lights to two different switches.  What will happen when this is discovered during my next annual? And can a certified mechanic ground my airplane for it?

The short answer is that a mechanic can't ground a plane. There are lots of discussions online about this, and the typical scenario seems to be that a mechanic "refuses to sign off an annual" or something similar. (There are other scenarios too, where the mechanic refuses to return the aircraft and/or logbooks to the owner because of a dispute over payment or work performed, but that's a legal issue, not an aviation one.)

AOPA has two useful articles (here, here) on this topic, written by Mike Busch (a well known A&P and author). He says:

Who can ground an aircraft?
FAR 91.7 forbids a PIC from flying an aircraft that is unairworthy,
although FAR 21.197 (Special Flight Permits) allows the FAA to grant
special dispensation to fly an unairworthy aircraft (usually for
repositioning purposes). There is no FAR that empowers a mechanic to
ground an aircraft. Mechanics are not the safety police.

When it comes to signing off on maintenance, there are two cases: required inspections (e.g. annuals), and general maintenance (e.g. an oil change). Required inspections are governed by 14 CFR 43.11.
43.11(a)(4) says:

[...] if the aircraft is found to be airworthy and approved for return
to service, the following or a similarly worded statement—“I certify
that this aircraft has been inspected in accordance with (insert type)
inspection and was determined to be in airworthy condition.”

43.11(a)(5) says:

[...] if the aircraft is not approved for return to service because of
needed maintenance, noncompliance with applicable specifications,
airworthiness directives, or other approved data, the following or a
similarly worded statement—“I certify that this aircraft has been
inspected in accordance with (insert type) inspection and a list of
discrepancies and unairworthy items dated (date) has been provided for
the aircraft owner or operator.”

In other words, even if the mechanic finds that the aircraft isn't airworthy, they're still required to make and sign a logbook entry to document that. The key point that Mike Busch makes is that what happens next is up to the owner, not the mechanic:

The owner must correct those discrepancies before the aircraft may
flown. He is free to have them corrected by any mechanic he chooses.
There’s no need for the inspecting mechanic to look at the aircraft
again. The next annual comes due in 12 calendar months.

The owner might ask the same mechanic who did the inspection to make repairs, or a different mechanic at the same airport. Or they might ask the FAA for a ferry permit to move the aircraft to another location for maintenance. Or they might just fly the aircraft anyway, knowing it isn't airworthy.
As for other maintenance that isn't a required inspection, 43.9(a)(4) says (emphasis mine):

If the work performed on the aircraft, airframe, aircraft engine,
propeller, appliance, or component part has been performed
satisfactorily, the signature, certificate number, and kind of
certificate held by the person approving the work. The signature
constitutes the approval for return to service only for the work
performed.

Here's Mike Busch's commentary on that:

Those two sentences bear careful reading. The first sentence makes it
explicitly clear that a mechanic’s signature on a 43.9 logbook entry
does not signify anything about the airworthiness of the aircraft. It
signifies only that the work the mechanic completed was performed
satisfactorily. [...]
The second sentence makes it clear that the mechanic’s signature does
not constitute an approval for return to service for the entire
aircraft (the way an annual inspection signoff does). It constitutes
approval only for the work the mechanic performed.

So coming back to your specific wiring scenario, if the mechanic performs a required inspection and determines that the change makes the aircraft unairworthy, they would document it as a discrepancy per 43.11. That means the aircraft is not airworthy, but how to make it airworthy is your decision, not the mechanic's decision.
Finally, if you're not sure how a mechanic would react to your wiring change you should probably find out. It's possible that the aircraft is already unairworthy, but that depends on a lot of details: type of aircraft, certified vs experimental, any applicable ADs etc.


Why is LGA's Instrument Approach Procedure VOR-H misaligned with the runway? I was looking at LGA's Instrument Approach Procedures, and I noticed that on this IAP plate the final segment (CHUGG to MAFAS) is misaligned with the runway. How should I interpret this? Shouldn't be aligned with the runway, in order for the aircraft to be able to land?

Not all approached are aligned with a specific runway; some like this VOR approach into KLGA is not and just uses circling minimums.

It is anticipated that the aircrew will, after reaching the MAP at MDA, visually confirm that they have the intended runway of landing in sight, thence circle to land on it visually at or above the circling minimums published.  The landing runway would be given by ATC or requested by the flight crew thence approved by ATC.

Nonprecision approaches with circling minimums only are quite common.  They are created this way only if:

  The final approach course alignment with the
  runway centerline exceeds 30°.

  The descent gradient is greater than 400 ft/NM from
  the FAF to the threshold crossing height (TCH). When
  this maximum gradient is exceeded, the circling
  only approach procedure may be designed to meet
  the gradient criteria limits. This does not preclude a
  straight-in landing if a normal descent and landing
  can be made in accordance with the applicable CFRs.

  A runway is not clearly defined on the airfield.

See the FAA’s Instrument Procedures Handbook.


Does any company (or country) still use Zeppelins or airships? Why not? I just like them a lot when I see'em in movies and I was wondering, are they still being used anywhere? Are there any companies working on them?

If the answer is, as I expect, "Nope", I have to ask why?
(Update: the "why" is more or less explained here Why are airships not more popular? , I still hope the answer is not "Nope"!)

Naïvely I would've thought they should be useful for heavy cargo, passengers, cheaper and safer than planes...

Zeppelins had a rigid skeleton and several internal gas bags. None of them are still in operation.

Airships today are blimps, that is, one big gas bag which is kept in shape by internal pressure, which in turn is regulated by ballonets.

The only airships flying today are used for

Advertising (Goodyear blimps, MetLife blimps)
Military observation (Lockheed Martin P-791)
Sightseeing tours (Zeppelin NT)

All attempts (and there were many) to use airships for cargo transport have eventually failed, sometimes spectacularly.


What is the lump on top of the Boeing 737? What are the lumps (Circled) on top of these two Boeing 737s? I looked it up but I only found the answer for one specific Virgin Blue 737.

Original image source

It is the antenna for the inflight wifi system. The Southwest aircraft has a Ku band antenna on the top, allowing it to access the internet through satellites. The United aircraft appears to have a similar system.


Does the payload of an ICBM or regular airplane bomber explode if the ICBM or bomber is shot down? As the top says, does the payload of an ICBM or regular airplane bomber (please excuse my ignorance) explode if the ICBM or bomber is shot down? So, say a defense laser in space (yes, I know; this is hypothetical for a setting, but) disables an ICBM in mid-flight, would the bomb detonate as well? If I recall correctly, even regular bombs shouldn't explode if the bomber explodes, that is, the bombs are meant to go off exactly when the bombardiers wish them to go off. Thanks.

Usually it won't set off the payload.

The payload is designed in a way to prevent it from going off prematurely - say it needs to be armed before it can go boom. Usually you would only arm the trigger mechanism in the end phase - directly before payload delivery since you want to hit your target and not your own installations.

Modern explosives are remarkably unwilling to go off without the correct primer. Some of them will not explode even when set on fire (and just burn in that case). However some others might go off if they just get heated enough.

For nuclear weapons, it's even more difficult to determine. If the conventional explosives go off in an unpredicted pattern, you might have a conventional explosion but not a nuclear. If these explosives do not go off in the right pattern, the bomb might never reach criticality and fission (and possibly fusion) stage of the weapon will never trigger. In any case, wherever it went of, the bomb might scatter plutonium, uranium and other radioactive material where it was shot down.

That said, an aircraft or missile crashing can cause ordnance to arm and there was at least one case where a US bomber with live nukes crashed, the bombs partially got armed on crash but didn't trigger in the end. https://en.wikipedia.org/wiki/1961_Goldsboro_B-52_crash


Why were most of the first-generation-Learjet wing mods never approved for the Learjet 23? First-generation (straight-wing1) Learjets (the 23, 24, 25, 35, and 36) are, rather infamously, beasts to fly, due in part to their hideous stall behaviour;2 due to their flow-separation-prone laminar-flow wings, they have a tendency to stall at a fairly high speed with little to no warning and roll uncontrollably to one side, something that caused a considerable number of fatal crashes upon landing.

For this reason (and others), a number of modifications were devised over the years for the first-generation Learjet wing to improve its flight characteristics:

The Dee Howard-Raisbeck Mk. II wing mod, which lowered the aircraft's stall speed considerably, was released in 1975.
The following year, Gates Learjet responded with the Century III modification pack, which both lowered the aircraft's stall speed (by modifying the cross-section of the wing's leading edge) and modified the aircraft's stall-warning system to alarm earlier if the aircraft's angle of attack is increasing rapidly.
In 1979, the Softflite modpack (a set of stall strips and wing fences installed on the upper surfaces of the wings) became available; it considerably improved the straight-wing Learjets' stall characteristics, changing their behaviour from an abrupt stall and violent rolloff to a gradual, wings-level stall.

Learjet 23 owners, however, are unable to benefit from most of these improvements, as most of them were never approved for use on the 23.  The Mk. II modification was approved for the Learjet 23, but the Century III and Softflite modpacks - with the former's improved stall-warning system and the latter's benignified stall characteristics - were made available only for the Learjet 24 and up:

  The manufacturer's Century III and Softflite wing modifications to improve the airplane's slow speed and stall characteristics have not been approved for the [Learjet] Model 23.  The Dee Howard-Raisbeck, Mark II, a similar wing improvement modification, has been approved for the Model 23, but the accident airplane was not equipped with this modification.  ...  [NTSB AAR-83-01, page 16 (numbered as 13).]

Why was the Learjet 23 excluded from most of these stall-protective modifications?

1: Technically, the wings of first-generation Learjets do have some sweep.  However, the wings' sweep angle is too small to make a meaningful improvement in the aircraft's flight characteristics; the 23/4/5 have the leading edge swept at 13° and the trailing edge unswept (giving a quarter-chord sweep angle of only 9.75°), and the wings of the 35/6 are based on the 23/4/5 wing, with the addition of completely-unswept wingtip extension panels which give it an even lower effective sweep angle.

2: Other bad points: an original autopilot with a great tendency to produce large, spontaneous pitch inputs in either direction, a tendency to dutch-roll violently if said autopilot failed or was disconnected at cruise speed, or if the aircraft's yaw damper failed or was disconnected at any time except when configured for takeoff or landing, a mach-tuck susceptibility best described as "extreme" at not far above MMO on an aircraft with easily enough engine power to exceed that limit in level flight (aggravated by an overmach-recovery procedure which, as it turned out, was very likely to send the Learjet into an unrecoverable dive), et cetera, et cetera.

The cost of approving an STC for an aircraft can be quite expensive and the return on investment may not have been worth it.

------------------------------------------
|Aircraft   |  # Built |  Year Certified |
------------------------------------------
|Learjet 23 |    104   |       1964      |
|Learjet 24 |    259   |   1966 to 1976  | (All variants)
|Learjet 25 |    369   |   1967 to 1976  | (all variants)
|Learjet 35 |    670   |   1974 to 1976  | (all variants)
|Learjet 36 |     64   |   1974 to 1976  | (all variants)
------------------------------------------

The Lear 36 is, for all practical purposes, a variant of the Lear 35.  If you take a look at the list, the Lear 23 is the oldest with the least number built and that would weigh heavily on whether or not to pursue an STC.  If an owner of a Lear 23 wanted to purchase the STC and absorb the cost of the certification, these would have been made available to those aircraft as well.

An owner can effectively upgrade their Lear 23 to a Lear 24 by completing and engineering change record (ECR 227, ECR 230 or ECR 233 depending on serial number).  Once the new Lear 23/24 name plate is installed, the STCs may be applicable.

It is also just a guess.  The FAA (as we know it now) was formed in 1967.  It is possible, the STC holders tried to get their modifications approved by the FAA for the Lear 23 but since the aircraft was certified before the FAA was formed, they may have declined or required the aircraft to meet current aircraft design standards and that may have been cost prohibitive.


What FAA regulations govern a US International Airport name change, such as McCarran International to Harry Reed International? What FAA regulations govern a US International Airport name change, such as McCarran International to Harry Reed International or Las Vegas International Airport?  Can the citizenry petition the FAA for or against such a change?

The owner of the airport determines the name.  If there is a dispute, courts have settled naming rights.

Whether the airport offers customs determines the "International" designation.  Some airports have no international flights, yet have the "International" in their name. They will have customs available, at least part time.

Side story: At one time, using a grass strip a couple of farms over, I asked a neighbor who worked for US Customs if I could fly directly to the grass strip (which did not even have a FAA Airport Identifier assigned) and clear customs there.  He said I could, and had me notify customs inbound, so they would notify him to meet me at the grass strip for inspection.  Doing that made trips from Canada to back home free of the hassles of dealing with a big airport.


Is it possible as a pilot to get the ICAO proficiency language level for a not official language in the ICAO? I was wondering if it is possible to get the proficiency language level in German for example, as it is not an official language for ICAO. If I would want to apply for a German airline as a pilot, can I get that document, the same as I can get it for Spanish or English?
I am not 100% sure but I think pilots in Germany, Austria and Switzerland can communicate in German so I guess they need those competencies (although when being native you don't have to take the exam)

Maybe it's a dumb question but I haven't found an answer yet.

As the others pointed out, there's no ICAO language proficiency test for German.

How it works for German at least in Germany is with a special "Radio operator license" (Sprechfunkzeugnis) that's part of (German) pilot licenses. For IFR that's only in English, but for VFR you have the choice of doing it in English, German or both. It's called BZF I (English + German), BZF II (German) or BZF E (English). According to the German Wikipedia, there are similar systems in place in Austria and Switzerland.

Even for VFR in Germany it's totally possible to do it in English, as I believe there are no more German-only speaking airfields. But especially on smaller fields where radio services are provided unpaid by people in their free time, they are a bit happier when using German.

And even on the bigger VFR fields with professional ATC personnel, my experience is that it's sometimes hard for them to remember, which aircraft in the pattern is communicating in English and which in German and then they try to translate position reports they get in one language from one aircraft into traffic advisories for other aircraft in another language. That's why it's sometimes recommended for pilots flying more often VFR in Germany to maybe also do the BZF in German as most VFR traffic is still done in German.


How can a foreign pilot get renter's insurance in the USA? I'm about to go to the United States and do some flying. I sorted out my FAA license conversion but I was wondering how to get aircraft renter's insurance. It seems that some schools / clubs require this, and it's not included in the hire contract.

I googled a bit but it's seems that all the policies are for US residents and annual contracts. I'm more interested in a month or so.

Anybody else who's had this problem? Any suggestions ?

Most flight schools in the US have an easy policy for renting out their planes:

You go there, you do a checkout flight on an airplane with one of their instructors, and you can go ahead and fly as much as you want.

The planes are then insured by the flight school, and you pay for the insurance by paying an hourly fee to the flight school. The checkout flight is necessary for the insurance, and is most of the time valid for 90 days. After that, another checkout flight might be required.

You, though, might not be included in that insurance. If something happens to you, the flight school's insurance will probably not cover the costs you might have.

I don't want to advertise on here, but for if you are interested I can show you a nice flight school in Florida.


Do the captain and first officer log the same hours for a flight? On planes that have a captain and a first officer, how are flight hours logged and split between the two?

Are the hours split between the Capt and First Officer based on who is physically piloting the plane or are the same amount of hours are assigned to both?

Both log time, they just log it as different things. This is similar as a student and instructor logging time, but for different roles. The captain is the pilot-in-command and thus logs 'PIC', the F/O is second-in-command and logs 'SIC'.

The pilot who is tasked with controlling the plane is called 'PF' or "pilot flying", and the other is called 'PNF' or "pilot not flying", or "pilot monitoring". This doesn't affect who's PIC and who's SIC though, and if I understand correctly, it's not generally logged who's actually flying.


Can autothrust keep the plane aligned with the runway during crabbing? I'm not talking about the entire auto pilot system, but only the thrust. Because I think, when experiencing crosswind during landing, the speed of wind may fluctuate and on 3 digit approach altitudes and below, it is hard for pilots to balance the forces with counter-forces without missing the runway. Is auto thrust precise enough to balance those forces in such short distances and short amount of time, and keep the plane aligned with runway after pilot points the plane against the wind?

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

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

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

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

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

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

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

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

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

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

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

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

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

quote from Boeing 777 Flight Crew Training Manual

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