texts: What is the standard power supply and voltage supply on modern airliners?

texts:
I'm looking at reducing the weight footprint of some of the computer systems on a commercial liner. A big consumer of weight seems to be in power supplies and conversion. Being a computer guy, I don't know anything about avionics or electricity on commercial liners.

Is there a standard power supply or voltage supply for modern air liners?


texts: What is the cable connected to a plane for?

texts: I've seen that airplanes are connected to some wire like in the picture. What is it's name and what is it for?


texts: Do flight attendants do pinch-hitter training?

texts:
I was watching a Captain Joe video (Can a PASSENGER land a PLANE?) and he mentioned that he left out the 20 minutes it took the person to even figure out how to communicate with ATC. It seems to me that with a little training, a crew member would be much more prepared to handle such a circumstance.

Even if it's just one pilot, I could see the benefit of having a crew member able to share the workload (communications, checklists, etc).

I was wondering if there are any airlines that provide pinch-hitter type training to flight attendants (even if it's just a classroom course) in case one or both of the pilots are incapacitated?


texts: Can the design for neutral stability reduce trim drag?

texts: If one were to design an aircraft to have neutral longitudinal stability would this reduce the required horizontal stabiliser surface and hence trim drag?


texts: How does turbojet thrust change with altitude?

texts:
I am studying the rate of climb of turbojets, I don't know how the thrust varies with altitude and in particular which are the differences between necessary thrust and effective thrust.
Hope being clear, I can't translate properly maybe so ask and edit !


texts: What should you do if you are forced to enter restricted or prohibited airspace?

texts:
Apparently, even if you have declared an urgent situation or an emergency, you cannot enter restricted or prohibited airspace, and ATC may not be able to clear you into the area. So, my question:

If you had a serious condition onboard an aircraft (say severe icing) and high terrain (I know, you probably haven't planned) in all directions except for restricted or prohibited airspace, what should you do to try and make sure that people are aware of your situation and can try and minimise the risk of doing so?


texts: How do I estimate how much air flows through the intake due to engine suction?

texts:
I read that the intake mass flow ratio (not sure its translated to correct lingo) can be expressed as:

$C_A = \frac{\textrm{airflow through air intake}}{\textrm{air density } \times \textrm{ speed of free flow }\times \textrm{ intake area}}$

A graph of this could look like:

Now my question is two fold:

What is the correct english term for this factor?
How do I estimate how much air flows through the intake due to engine suction.


texts: Is there any way to relieve the Pilot in Command?

texts:
Is there any way to relieve the Pilot in Command besides hijacking and incapacitation?

This question comes from a comment by rackandboneman, who says:

  And whose authority is sufficient to make an active pilot in command a pilot out of command?

I gave a joking response, but it got me thinking: are there any ways to remove a PIC from command without that PIC's consent other than hijacking or incapacation, either in the United States or worldwide?


texts: Is there a database of radio-frequencies for airfields/airports in Europe?

texts: Is there something like a register of frequencies for airfields/airports in Europe? I am building a VFR flight planner and would be interested to autofill a form with the frequencies dependent on the given input data. Is there something like a database?


texts: Does extension of flaps 1, 2, 5 or 10 increase descent rates?

texts: Let's say you need greater descent rates than you can get with the full use of the speed brake in an airliner. Does it help to use the above flap positions in getting greater descent rates?


texts: Do modern flights and pilots have reservations about flying over the Bermuda Triangle?

texts: I know that the Triangle was pretty much legend back in the days but now, given that there is so much technology involved with respect to tracking and communications, do pilots, flights and airlines still have reservations about flying over this area? If so, why, and if not, are there regular flights/airlines that go over this route every day?


texts: I want to become a pilot, but as you know, I should take some training course on aviation. Currently I am searching for Aviation Scholarships because I can not sponsor myself. Can you give me some pointers please?


texts: Where can I find more information about that glass board in old aircraft carrier operations centers?

texts: When I was a kid, I used to read this comics about aircraft pilots in the 50's, and in the operations center of their aircraft carrier, they had operators using markers on a glass wall to keep track of operations. Any idea how that was called and where I can find pictures of it? Is it still in use today, or is it now all computerized?


texts: Why do turbofan engines have low pressure compressors?

texts:
In my understanding turbofan engines usually have 2 stages of compressors:

one low pressure compressor
followed by a high pressure compressor

But it looks like the high pressure compressor cancels the job done by the low pressure compressor, doesn't it?

What's the point of decreasing pressure in the first compressor if you then increase it in the second compressor?  Why not using only the high pressure compressor?


texts: Does go-around require more power than take-off?

texts:
The complete version of Buran spacecraft would have had two engines that were not sufficient for take-off under own power.

Is it possible to say that if the aircraft is not capable of taking off under own power (not sufficient), it should not be capable of going around (assuming weight and other circumstances are the same)?


texts: Why is the speed brake lever not a "spring" one that returns to the default position when released?

texts:
I was watching this video in which are described various systems on B737 but at around 6 minutes, it talks about speed brakes and necessity for pilots to maintain their hand on the lever to avoid forget to release them.

It seems perfectly sensible, but I'm asking why this is not a simple spring lever... if is very important that pilot don't forget lever in extended position, and for this reason is necessary that he's maintaining his hand on the lever, why don't make a simple lever that returns to default position after release?

This would sound even more secure... and in both cases pilot hand would be "busy".


texts: What is the ideal volume distribution for minimization of transonic drag?

texts: I am aware what the area rule states - my question is what is defined as "as smooth as possible area distribution" - Is there a formula for the curve?


texts: Is there ATC audio from the Sled Driver Speed Check story?

texts:
I love this story, like a lot of people, but is it possible to find the actual ATC recording from that story?
Excerpt:

Then, I heard it. The click of the mic button from the back seat. That was the very moment that I knew Walter and I had become a crew. Very professionally, and with no emotion, Walter spoke: "Los Angeles Center, Aspen 20, can you give us a ground speed check?" There was no hesitation, and the replay came as if was an everyday request. "Aspen 20, I show you at one thousand eight hundred and forty-two knots, across the ground."
I think it was the forty-two knots that I liked the best, so accurate and proud was Center to deliver that information without hesitation, and you just knew he was smiling. But the precise point at which I knew that Walt and I were going to be really good friends for a long time was when he keyed the mic once again to say, in his most fighter-pilot-like voice: "Ah, Center, much thanks, we're showing closer to nineteen hundred on the money."


texts: Why does the second floor of the Boeing 747 occupy only part of the plane?

texts: Why does the second floor of the Boeing 747 occupy only part of the plane, while the second floor of the Airbus a380 occupies the entire space of the plane?


texts: What is the effect of wing flex on wing's airfoil shape and its performance effect on wing?

texts:
There are good amount of discussion on wing flex in this forum.

I am more interested in understanding the effect of flex on aerofoil shape of the wing and its impact on flight performance.

Do designers take into account the cross sectional shape change induced by wing flex while designing the aircraft? If not, is it because the effects are negligible or simply too complicated to simulate?

Also, does the shape change induced by wing flex help in improving the performance?


texts: What might happen if I receive flight instruction in a plane with an airworthiness deficiency?

texts:
Let's say I were to a day VFR flight with a new instructor, in hopes of eventually pursuing Sport Pilot - Airplane privileges (U.S.A.)

During the flight, I notice the plane has a minor airworthiness problem. It doesn't affect the safety of the flight, but something required is missing. The magnetic compass, for example, is loose in the glove box instead of mounted on the instrument panel. I bring it to the instructor's attention, he downplays its significance and says he plans to get it fixed in a few weeks.

The flight goes otherwise well. The instructor fills out & signs my logbook in the usual way.

Is this legal instruction time? If this instructor were to get in trouble over instructing in an un-airworthy plane, could that void those instruction hours' applicability towards the sport pilot hour requirement?

(and the more subjective question: practically, how worried should I be over something like a missing compasss? Is it really as minor as I think? Anything I should be looking more closely for before I fly again with him?)


texts: What does "composite panels on a frame" mean?

texts:
Reading about composite materials in the 787 on Wikipedia, I came across this:

  Carbon fiber, unlike metal, does not visibly show cracks and fatigue, prompting concerns about the safety risks of widespread use of the material; the rival Airbus A350 uses composite panels on a frame, a more conventional approach, which its contractors regarded as less risky.

I bolded the curious part. What does "composite panels on a frame" mean exactly?


texts: In the US, how does the distinction between E2 and E3/E4 airspace affect pilots?

texts: In the US, practically speaking, how does the distinction between the E2 and E3/E4 subtypes of Class E airspace affect pilots?


texts: How do airlines plan their payload for multiple flights in a day?

texts:
Of course, this isn't specific to a single airline or airplane. As a base rule, it is needless to say that airlines want to profit as much as they can and the payload is a strong factor to influence the profits.

That said, let's take an example of a B737 of ABC Airlines that will be making stops to 3 different destinations before reaching its final destination.

Assuming 2 of the 4 legs have sold all seats, while the other 2 have sold only half:

How will the fuel on-board be planned? Will it benefit to carry enough for 2 legs so that they spend the least amount of time at the stop-over?
Will it benefit to only have the required fuel for one leg (including the reserves and alternate), and thence allow more luggage from passengers which would otherwise be declined?
Are these decisions made by dispatchers, pilots or a different department? Are they made right before each flight or pre-planned well in advanced?

I'm asking these because I want to understand how airlines plan their flights as to, you guessed it, maximize profits while still maintain inflation schedules and passenger satisfaction.


texts: What happens if an aircraft tries to land at MTOW (if greater than MLW)?

texts:
Here's a scenario:

Just after Take-Off, there's an emergency on-board and pilot wants to land immediately. But, the weight of the plane wouldn't have decreased by large margins (usually 0.02*MTOW). Is the aircraft allowed to land with a weight more than Maximum Landing Weight?

What will happen if the plane tries to lands with a weight more than Maximum Landing Weight?


texts: Why would a flight from North America to Asia sometimes fly over the Atlantic?

texts:
I am going to take AC031 from Toronto to Beijing in a couple of weeks, I searched its flight path, most of the time it will fly westbound after taking off from Toronto and continue west across the north pole area and land in Beijing, but yesterday it flew eastbound, across the Atlantic, this is very strange since the distance is a little bit more than flying westbound.

Why?


texts: We know about the existence of Boeing planes like the 737, 747, and other planes. But where did the name "Boeing" come from?


texts: Do aircraft weigh less on an eastward flight than a westward flight, due to the Eötvös effect?

texts:
Aircraft speed is added to earth rotational speed when flying to the east, centrifugal force is increased compared to a westward flight. That means the aircraft weight is reduced = smaller lift, means flight with lower AoA = lower induced drag.
Can this in reality be used for less drag and greater speed or better fuel consumption?
If a plane flies east with speed of 1666km/h, centrifugal acceleration is 0.134m/s2, that means it has 1.37% less weight. If the plane weighs 78700 kg then the reduction in weight is 1078kg, when flying east!
If a plane flies westward at 1666km/h (same as earth's rotational speed) then looking from space (inertial frame) plane looks stationary, so centripetal force = zero.
This is the Eötvös effect:


texts: Can a F/O declare "My plane" to the Captain?

texts:
Let's presume an airline flight piloted by 2 people: the Captain (assuming PIC role) and the F/O.

Is the F/O allowed to take manual control over the Captain actions?
Under what circumstances?
Could this create safety issues, for instance, the Captain trying to recover control from the F/O?
What does CRM suggest about this matter?


texts: Why do flight control cables not slacken during the cold temperatures at cruise?

texts:
Image source

Flight controls in airliners have long cable lengths in between the cockpit controls and the control surfaces. For instance in the picture above: the pilot operates the yoke, which deflects a steel cable running through the front fuselage and the wings, which then opens a servo valve for the hydraulic actuator moving the aileron.

The cables are made of steel, the aircraft from aluminium.
Thermal expansion of aluminium is twice that of steel.
The aircraft can be standing in the sunshine at 40°C, and half an hour later be at cruise altitude at -50°C.
The difference in thermal contraction would cause a couple of centimetres slack in the cables at cruise, with the pilot then experiencing a control deadband: turn the yoke some degrees and nothing happens. Or the cables would be appropriately tightened for the cruise situation, causing tight cables and high control friction at take-off: try to turn the yoke by pushing hard.

But the forces and (lack of) deadband are identical at take-off and cruise. How is this possible?

Edit

Yes there is a Cable Slack Takeup drawn in the picture, but the working of it is a little bit more complicated than it seems, I've added an answer below.


texts: Can an intercepting fighter jet force a small propeller aircraft down without completely destroying it?

texts:
A rogue aircraft may fly into a no fly zone, and be intercepted by standard military procedure. That involves increasingly intense attempts to establish communication. When all these fail, it may be required to force the aircraft to go down. The naive solution is to just shoot it down, which may be the right thing to do.

I wonder if it is possible for a F-16 fighter to force a small one propeller airplane to do an emergency landing? Either by making it try to get to the nearest airfield, or alternatively making it try to get to the nearest cornfield - or anything somewhat flat.

For example by disabling its propeller. By either breaking the propeller by  shooting at it, or shooting holes into the engine?

Would that work for a small aircraft?
Would it work more generally, like for commercial airliners?


texts: How does turning Errors in the Air Driven Artificial Horizon work?

texts:
Turning through 90°, 180°, 270° & 360°, the error is different. I can understand what is turning error and pitch error individually.

But why turning through different degree, the resulting error is different?


texts: Is it possible to take a liquid/gas inside aircraft cabin to contaminate the air?

texts:
As per the security rules, i think upto 100ml of liquid ( medicines, perfumes etc) can be taken on-board by a passenger but is it possible that, that 100ml can be converted to fumes/gas and contaminate the air inside the aircraft?

Any such incident has ever been reported?


texts: What is the difference between being instructed to land "as soon as possible" or "at nearest suitable airport"?

texts:
On commercial airliners, the FCOM (Flight Crew Operating Manual) sometimes gives instructions to the pilots to land sooner than planned, following various in-flight failures or emergencies. For instance, for serious emergencies (e.g. in-flight fire), the pilots would be instructed to LAND ASAP (as soon as possible), as there is a real danger to the aircraft and its occupants if they stay in the air any longer.

For less severe situations, the pilots would be instructed to LAND ANSA (at nearest suitable airport), which gives them more leeway in deciding where to land.

My question is: other than the fact that LAND ASAP is obviously more urgent than LAND ANSA, could anyone go into more details as to how a pilot would interpret these instructions, and how they differ? (for instance, does LAND ASAP mean "land on the nearest reasonably smooth surface", or is it less extreme than that? Are there guidelines on approximately how long you should keep flying after receiving a LAND ANSA instruction?)


texts: I was talking to a pilot, and he said that the alpha floor had been activated, and I did not have time to ask him to explain this. So, can you clarify my doubt, please?


texts: How and why do wake vortices come together to form two tip vortices?

texts:
Wake vortices are created all along the wingspan but, the vortices come together to form two tip vortices. How exacly does this happen and why does it? I know that wake vortices push air to the side. Does this sideways moving air somehow pull the vortices to the tip?

Here is a picture of what I am talking about:

This picture shows that there is downwash and vortices along the whole wing span but, for some reason there are only two vortices at the tips.

One theory I have is that the up wash from the vortices follows the downwash from the rest of the wing and they spin around in a circle but, I am not completely sure


texts: What is the correct ATC phraseology for tower to clear a practice approach?

texts: If you have an aircraft (training flight) that is doing practice instrument approaches and ATC is notified that they will fly the approach and then go missed, what is the correct phraseology for the tower? "Cleared to land" or "cleared missed approach"? Where can I find this information in a document?


texts: What is the noise level inside the Tu-114's passenger cabin?

texts: Was the Tu-114 as noisy inside the passenger cabin as the Tu-95 bomber was said to be?


texts: What is the up-to-date disposition towards narcolepsy in the U.S.A. for obtaining a pilot license?

texts:
Citation: What medical conditions does the FAA consider disqualifying?

In the past, I recall this page having listed narcolepsy, but I find no mention of narcolepsy anywhere relevant on the FAA website anymore. Can anyone enlighten me as to whether I am just missing it somewhere, or if there is knowledge of this specifically having been changed? It would surprise me greatly if this were not a disqualifying condition, but I want to find official information on it.


texts: Dimensional analysis with wingspan length?

texts:
I need some help in understanding the fundamentals of dimensional analysis.
The following is is from "Fundamentals of aerodynamics" by John D Anderson, fifth edition:

Why is the wingspan length not added to the variables that the aerodynamics force R depend on?


texts: Why does the cabin air sometimes smell of kerosene?

texts:
Why does the cabin air sometimes smell of jet fuel, although bleed air is tapped before it comes in contact with fuel ? How is this possible?

I have smelled this a couple of times in my life (twice extremely irritating), mostly during boarding/taxiing but at least once also during the flight (although in that case I don't remember if the smell was already present before take-off and merely lingered on).

Apparently a similar observation was reported in Q25405 but limited to the taxiing phase, whereas I witnessed the smell when the plane was still connected to the PBB (and also in-flight with the caveat above). The root cause may differ.

EDIT:
Meanwhile, I have found a satisfying answer on the net, but cannot add it anymore since the question is closed:

  « You’ll occasionally notice a strong odor when the plane is on the
  ground – a pungent smell similar to the exhaust from an old car or bus
  that fills the cabin shortly after pushback. Usually this happens when
  exhaust gases are drawn into the air conditioning packs during engine
  start. The wind is often to blame, causing air to backflow or blowing
  fumes through the pack inlets. It normally lasts only a minute or so,
  until the engine is running and stabilized. It’s unpleasant but little
  different from the fumes you occasionally breathe in your car while
  stuck in traffic. » (source)

(Notice that in my cases it lasted definitely much longer than "only a minute or so".)


texts: Is it normal to use only one hand on the yoke while landing?

texts: In this video taken from this question, the video shows the pilot using one hand on the yoke and one hand on something else (perhaps the throttle? I'm not a pilot). Is it normal to do landings with one hand?


texts: Is there a triangle representation for the Canadian airspace?

texts:
I'm looking for the following figure, except modified for Canadian airspace.
Does anybody have a copy, or can help me modify this one? I searched everywhere and could not find one.


texts: IFR Currency with a safety pilot who has a BasicMed

texts: Here’s my situation and question.  For my IFR currency, I’ve asked a friend to be the Safety Pilot.  He’s aptly qualified BUT he does not have the traditional Medical, but rather he has BasicMed.  My question is; Can I still use him as a Safety Pilot, without jeopardizing my IFR Currency?  If he’s deemed PIC, can I still claim the time and use the IFR work (approaches, hold, tracking, etc…) for my IFR currency?


texts: Recently, when flying (as a passenger of a regular flight) from Stockholm/Arlanda, there was quite a long bus ride from the gate to the aircraft, because the latter was "short parked", according to the announcements at the gate. What does "short parked" mean? "Faraway parked" would have made more sense from a passenger point of view.


texts: What do the different colors of weather stations indicate on SkyVector?

texts:
In this particular map

from SkyVector, what are the meanings of the different colored circles, and for the different amounts of 'fill-in'?

It's obvious by hovering over them, that they are weather stations, as the weather info will pop-up, but there doesn't seem to be anything (to my untrained eye) about the weather pop up that would indicate a need for the different colors.
It's also obvious that the color doesn't indicate something permanent about the station, as last Friday, there were large swathes of different colors across the USA, while today almost everything is green.


texts: Why might a moving map Android app consistently record altitude off by 120 feet?

texts:
I fly Cessna 172 and Cherokee Warrior both older models without a GPS.
I have a very useful freeware navigation app on my android phone which is really good in every regard other than it always reads my altitude a bit higher than were I am.

Best example is when I am taxiing my track and its projection on the ground which should have merged are separate.
The app does not have any setting for adjusting this! I wonder if there is any explanation for this. The app superimposes my 3d coordinates on a moving sectional chart. I re-installed the app which didn't help.
Here is my flight KML on Google Earth on my approach and landing to Catalina airport last Sunday.


texts: Is the life of pets considered when dealing with a cargo fire indication?

texts:
In this event, the crew of a 777 responded to a spurious cargo fire indication by activating the fire suppression system, which suffocates the cargo area. Presumably any pets held there would have died as a result.

What are the SOPs for fire suppression when carrying pets in the cargo hold? Are they held in a separate compartment?


texts: Why don't airliners use in-air refueling systems?

texts:
Right now if an airliner wants to fly a really long distance (eg., a Boeing 787 flying from Seattle to Tokyo), it has to load itself down with lots and lots of fuel, which in turn weighs thousands and thousands of pounds.  This, of course, makes the flight of the aircraft less efficient than it could be1.  Thus, if the craft could theoretically carry half as much fuel, that should increase the fuel efficiency of the craft, right?2

Mid-way refueling seems like it would be a Good Idea™ at that point.  Of course, landing would add a heck of a lot of time to the flight, so it seems the better option would be mid-air refueling.  It would allow for the aircraft to be more efficient, without the need for stopping on a long journey.

Boeing and Airbus both make a few airplanes | that can do | mid-air refueling, in fact one of them is a highly modified 747-200 (properly called a VC-25) used as Air Force One:

(source: wordpress.com)

I assume that, because Airbus and Boeing's engineers and sales managers are really quite smart, they have a really good reason that they don't fit/sell this feature on any civilian transportation aircraft.  But I'm not sure what that reason is.

Does anyone know why airlines do not use aircraft that are capable of mid-air refueling?

1 If I'm not mistaken, increased weight means an increased AoA to maintain level flight, which in turn increases induced drag from the wing.  Less fuel would mean less induced drag or, if mid-air refueling were common practice, a wing that was designed to be more efficient because it was required to handle less weight.

2 I don't know by how much, if it's not that much, well, that might explain why nobody does this.


texts: What did the controller say during my approach to land (audio clip)?

texts:
I recorded this ATC audio clip during a recent flight.

I'm not sure but he may be saying,

  6CP, cancel lining clearance......(missing)....traffic will be in position.

Can you complete this transcript? And I don't understand what "cancel lining clearance" is...


texts: Does the radar altimeter's position affect its accuracy?

texts: I have seen the location of the radar altimeter is different between Airbus and Boeing. Airbus has it almost at the tail, Boeing has it forwards. I would like to know which one gives the height more accurately?


texts: Can a Phalanx-type Close-In Weapons System (CIWS) engage small aerial targets like drones, UAVs, rotorcraft? Is there any case that Phalanx was used against aerial targets?


texts: Are there laws about how close military aircraft can fly to passenger jets, and are they enforced?

texts:
Yesterday I was on a passenger plane flying at 35000 feet from Denver to JFK on a fairly clear day. Just west of Sioux City, we made a relatively sharp, but short, right turn for whatever reason (may be unrelated). I happened to be looking out my window and caught what appeared to be a military fighter jet (presumably from the Air Force base there) flying in the opposite direction. It blew past my field of vision in a fraction of a second, slightly below us and off to the right, close and fast enough to startle me. It left a beautiful set of trails but, while my distance judgments aren't very good from a plane, appeared to be no more than ~1000 feet away from us (based on its size, I imagined it to be about 4-5 NYC city blocks away, that's my only reference). The passing aircraft's trails were dead straight at least as far back as they extended before dissipating. I didn't get a chance to ask the pilot about it after the flight.

My only knowledge of separation laws is from wikipedia, which seems to state a 2000 foot limit above 29000 feet.  I absolutely might be misjudging distance, but this aircraft seemed to be well under a half a mile away. So my question is: Are there a different set of separation laws for military aircraft, or perhaps are existing laws just not as strictly followed / enforced by the military? Would the pilot of one of the aircraft expect some sort of reprimand later? Was this a normal occurrence or was it a close call?


texts: How can the fuel decrease evenly from both wing tanks when an A320 is running on APU only?

texts:
I stumbled over this sentence in a training material about fuel leak:

"If the fuel quantity symmetrically decrease in both wing tanks and the fuel quantity in the center tank decrease, the fuel leak comes from the center tank or the APU feed line."

Regarding the APU feedline part, what I don't understand is if the APU is feeding from the left tank always regardless if it's by the fuel pumps or it's own pump (in case the fuel pumps are off) how can the fuel decrease evenly from both wing tanks?


texts: How (and when) to use the BFO button on an ADF?

texts:
BFO (Beat Frequency Oscillator) is a function of the ADF, I know that it has something to do with different types of NDB, but I do not know which type. And how and when do I use it?

I heard that depends on the type of emission of the NDB in use. For what I know there are N0NA1A or N0NA2A but I do not understand how this imply the use of the BFO push button or even the differences (from operational point of view) between the two!


texts: Can the Mexican presidential aircraft be sold?

texts:
I have read that the next Mexican president is trying to sell the B787 that serves as presidential transport, and that it was already made an offering to Boeing for it.

As far as I know, the VIP/presidential aircraft are more or less custom made, so it's hard to imagine that anyone would buy it (I'm guessing an airline would retrofit the plane for his own configuration and that would be more expensive than buying a new plane).

But perhaps the manufacturer would use it for leasing purposes.

Then, it is viable to sell this presidential aircraft (or any other)? How much can be paid for it (compared to the initial value)?

Reg: XC-MEX


texts: Why does the A380 not have front windows on the top floor?

texts:
The title says it all.

On the 747, the cockpit is in the upper level and in the lower there's equipment (radar, avionics, etc.)

But on the A380, the cockpit is in the lower floor and there's no equipment in the upper floor. So I think it could be technically possible to place some front windows in order to get a pilot-like view.

I guess that would reduce the aerodynamic efficience of the aircraft, but maybe it could be compensated by higher prices on those exclusive view seats?

Has any aircraft like that ever existed or designed?


texts: Why does a jet's combustion energy propel the engine forwards rather than acting equally in all directions to create zero thrust?

texts:
I'm a novice.  I have high school physics and I've seen many explanations of how a jet engine works.   To paraphrase: Fans compress air into a chamber where combustion energy is created, which spews out the back of the engine, propels the plane forwards in a typical Newtonian action/reaction way, and also spins more fans that in turn spin the previously mentioned compressor fans.    I know that's not a precise explanation but it just serves to introduce my question.
Why does the combustion chamber not act more like, say, a hand grenade?  That is, why doesn't the energy act equally in all directions?  What makes it directional?   I have never understood this from the dozens of school-level explanations I've seen on the topic.   Why does the energy from combustion cause the "low pressure turbines" at the rear of the engine to drive the compressor blades and not the other way around?  Or the most likely scenario in my flawed understanding, why doesn't the energy act equally on all the fans in the front and back of the engine to create no net propulsion?


texts: What is this closed cabin / open cockpit biplane from the 1910s?

texts:
This photo was taken when Lieutenant Marix RNAS visited his old school, Radley College in Oxfordshire on 30 May 1914. Marix was awarded in October 1914 the DSO for bombing the Zeppelin sheds in Dusseldorf which was the first successful bombing raid of the war.

Is there anyway of identifying the aircraft? Perhaps from the registration number 104 shown on the aircraft tail fin?


texts: Why vacuum instead of pressure to power gyros?

texts: Why are most air powered gyro instruments powered by vacuum rather than positive pressure?


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

texts:
I often see people citing the wing flex tests, but with very little reference as to what kind of forces they're designing the plane to take.

I am specifically referring to modern day jetliners such as the Airbus A330.

The wings are tested to withstand 150 of the ''most extreme'' forces the plane will encounter. But what does this mean exactly? Not too long ago, a 777 experienced extreme turbulence, and the aircraft experienced vertical accelerations of +3 G. Would that have still been under limit load for the 777?


texts: How do commercial pilots know turbulence is ahead?

texts:
On commercial flights, an announcement will be made if turbulence is expected ahead and if the route will be adjusted such as moving to a higher altitude.

How do pilots know that turbulence is ahead in time to make an announcement and an adjustment? Is it weather equipment in the plane or the ground? Is it because they follow common routes and listen to reports from planes ahead? Are they notified from the ground? Is there some other way they know in time to prepare their passengers?


texts: Is there a simple relationship between angle of attack and lift coefficient?

texts:
Is there an equation relating AoA to lift coefficient?

I have been searching for a while: there are plenty of discussions about the relation between AoA and Lift, but few of them give an equation relating them.

I know that for small AoA, the relation is linear, but is there an equation that can model the relation accurately for large AoA as well? (so that we can see at what AoA stall occurs)

I am not looking for a very complicated equation. Can anyone just give me a simple model that is easy to understand?

(Of course, if it has to be complicated, then please give me a complicated equation)


texts: Why, after decades of redesign and enhancement, does it still rain inside B737?

texts:
For as long as I can remember, seats 1A/1B suffer from rain during acceleration/takeoff as the condensation pours down from the heavens, (well, the overhead panel where the reading lights, gaspers, etc. are).  I guess it was, at most, a minor inconvenience until pax started carrying more consumer electronics in their hands. Now it can be costly.

Obviously, I can fix the issue myself by avoiding those seats, but sometimes they're the only extra-legroom seats left, and I'm tall. I try to remember to keep my electronics pocketed until after takeoff, but it's so boring sitting there while 188 other pax try to stuff their inflated bags into straining lockers, and I forget.

I can understand that this rotation rain, or similar aggravation, might happen on a new aircraft design; something undetected until mass operations and not safety-critical anyway, but how is this still happening on an aircraft that first flew decades ago and has had so many enhancements?  I can't be the only one who has had a Seattle soaking, so why has this, possibly costly, annoyance not been fixed?  It can't be that difficult/expensive to cure, surely?


texts: Why does the F-111 have a capsule ejection system rather than a conventional system?

texts:
Following on from the questions F-111 emergency landing with no wheel; what is done to reduce risks when loosing a wheel? and
Are there any known incidents of ejections by capsule? What are the survival chances?

I wondered, what is the reason for the ejection capsule on the F111?

It doesn't fly particularly high or fast (compared to aircraft with conventional ejection seats). The only reason I can think of is that the pilots sit almost side-side and it would presumably be tricky to fire the first seat without seriously inconveniencing the remaining crew member.

Are there any side-side aircraft with ejection seats?


texts: How energy efficient is an aircraft take off?

texts: How much work is generally done by an aircraft (e.g. B737NG) in order to reach V_rotate, and how does this compare to the energy content of the fuel that is used?


texts: Why weren't the XB-70's wingtips fixed in the down position?

texts:
The XB-70's wing tips folded down in flight to:

improve directional stability at supersonic speeds
reduce shifting of aerodynamic center at supersonic speeds
reduce drag at high supersonic speeds

With thanks to Peter Kämpf's answer. Actually, this question was prompted by that answer, and quite a bit of it is 'borrowed' from there.

Wings in flight:

Source: interceptor.com

Landing with wings straight:

Source: Gawker Media

My question is why did they fold, instead of being fixed in the down position?

My assumption is that the plane already sat very high off the ground (probably to give clearance for take off/landing rotation), and lengthening the landing gear enough to allow the wing droop would have been a greater engineering issue than making the wing folding mechanism. Is there validity in that assumption, or, were the benefits of the wing droop at supersonic speeds detrimental at subsonic speed?

Some perspective of just how tall the XB70 was (click to zoom - that's a tall bird!):

Source: cybermodeler.com


texts: How has weight been reduced in commercial aircraft design and how will this trend continue?

texts: Reducing weight of aircraft has become a priority as the aviation industry seeks greater fuel efficiency and commits to strict emissions targets. How much weight has been cut from single and twin aisle aircraft in last 10 yrs and where? How much further can OEM's and suppliers cut weight in the next 10 years and in what components/equipment/furnishings will the greatest savings be made? I am looking for some fun and relevant facts on this subject for an article I am writing.


texts: What are the differences between the MiG 31 and MiG 25 (if any)?

texts: What are the differences between the MiG 31 and MiG 25, they look exactly the same, their overall performance the same. Is it the roles they were built for are different?


texts: What FAA requirements exist for electronic ignition systems on piston engines?

texts:
Most GA piston aircraft still use dual magnetos for their ignition system, but there are some STC kits available to add electronic ignition to common piston engines, and new aircraft often come with FADEC systems.

Are there particular FAA requirements for electronic ignition systems?

If so, what are they and how can you demonstrate compliance?


texts: Why do non-aerobatic aircraft have a negative G limit?

texts: Why do airplane wings have limit load of both positive and negative g's (e.g., the Weedhopper ultralight has a load factor of +5 and -2gs). Why not just have a positive limit load since most airplanes (like the Weedhopper ultralight) don't fly upside down? In particular, why the negative load factors?


texts: Does it make sense to do an emergency landing without nose gear in order to reduce stopping distance?

texts: Would a pilot decide to land without the nose gear down to increase friction if for example all the engines have suffered a flame-out and there is only a very short runway available ?


texts: Do airlines prefer younger pilots after a cpl?

texts:
I am currently 26, female and making financial arrangements to pursue a cpl after 2 years. The location probably will be Canada or USA. I am wondering if 29 is too late for commercial airlines. Do the airlines prefer younger pilots? Is there a max age limit for commercial airlines?
Thanks for the help.
Cheers,
Litali


texts: Does Global Entry give you any benefits when flying GA?

texts:
If I fly GA into Canada from the US or into the US from Canada, does having Global Entry give me any advantage? Can I taxi straight to the FBO or my tie down spot, or do I still have to taxi over to customs? Is there any ability to fly direct to a destination and not have to stop at a port of entry airport?

What is the difference between Pre clearance and Global Entry? Can you get pre clearance without having Global Entry?


texts: Is there a flexible "cloth-like" material that can be used as "skin" for a non-conventional wing?

texts:
I am in the very early stages of playing with the idea of an ornithopter derived aircraft. The intention is to be able to scale the resulting aircraft, to passenger (or useful payload) carrying capability.

Is there any material that is simultaneously light - but also strong enough to carry the weight of an aircraft (and it's payload)?


texts: Could in flight folding wing tips lead to a safer airliner design?

texts:
As a spin-off to the recent success of the Boeing 777x maiden flight, the effects of folding the wing tips in flight were considered.

Folding them down in cruise, like the XB-70 should increase yaw stability and create a slight anhedralling effect, which reduces Dutch Roll tendency.  More importantly, it would shift the Center of Pressure forward, eliminating the need for downforce from the tail.  This creates a desirable, fuel saving, staticly nuetral configuration.

But the real safety improving benefit would be to fold them down on approach to landing, requiring downforce on the tail to balance the lifting forces.

Would this not create a safer, staticly stable configuration, where approach speed can be trimmed?


texts: Where in the FAR or AIM is a high speed taxi defined?

texts: While monitoring coms I recently heard a Cessna Centurion that had just cleared the runway request a "high speed taxi", which was approved by the tower. I'm assuming that means he wants to taxi at a faster than normal rate to his FBO of choice. Are high speed taxis defined somewhere as something you can request of ground control?


texts: During an LPV or GLS final approach, can the extension of the aircraft's cross-section line intersect with the Y or X OCS surfaces?

texts:
I am studying Obstacle Clearance Surface construction using FAA's Performance Base Navigation manual 8260.58B as my guide. I am confused about the rules concerning aircraft's permitted altitude in relation to the OCS slope and the OCS 3D surfaces.
On page 79, a sample image for LPV/GLS final approach case is provided.

This is a 3D surface, for which the manual states:

3-4-4. Obstacle clearance surface. The primary area OCS consists of the W and X surfaces. The Y surface is an early missed approach transitional surface. The W surface slopes longitudinally along the final approach track, and is level perpendicular to track. The X and Y surfaces slope upward from the edge of the W surface perpendicular to the final approach track [see figure 3-4-3]. Obstacles located in the X and Y surfaces are adjusted in height to account for perpendicular surface rise and evaluated under the W surface.

Based on some calculations I made, from the pilot's point of view the aircraft's cross section seems to intersect with the Y OCS, even if the aircraft's theoretical position is not (it is always above the W surface since it is required by the OCS + ROC slope).
In other words, I would like to know whether the first case (please see left image below) is correct or it should always be like the second case (right image below).

Could someone point me in the right direction?
UPDATE
Since I have found some relevant information in ICAO's 8168 Volume I document, I would like to quote the passage below from Chapter 1:

1.3 AREAS
1.3.1 Where track guidance is provided in the design of a procedure, each segment comprises a specified volume
of airspace, the vertical cross-section of which is an area located symmetrically about the centre line of each segment.
The vertical cross-section of each segment is divided into primary and secondary areas. Full obstacle clearances are
applied over the primary areas reducing to zero at the outer edges of the secondary areas (see Figure I-2-1-2).
1.3.2 On straight segments, the width of the primary area at any given point is equal to one-half of the total width.
The width of each secondary area is equal to one-quarter of the total width.
1.3.3 Where no track guidance is provided during a turn specified by the procedure, the total width of the area is
considered primary area.
1.3.4 The minimum obstacle clearance (MOC) is provided for the whole width of the primary area. In the
secondary area, MOC is provided at the inner edges reducing to zero at the outer edges (see Figure I-2-1-2).

The above figure depicts the assumed lowest flight path in such a way that the cross-section does not intersect with secondary area's OCS surface. However, I am not sure if it is just an example for demonstration, and the aircraft is supposed to be anywhere inside the canyon-like 3D OCS.


texts: What kind of liquid can be seen 'leaking' from the bottom of a Boeing 737-800 engine?

texts:
I was on holiday over the Christmas holidays, and was sat in the airport awaiting our plane back to England, looking out of the large window which over looked aircraft that have just landed and the passengers get of, when a Boeing 737-800 turned up, looking at its left engine (I could not see the right engine from my viewpoint), I saw a clear liquid leaking from the bottom of it, what was this liquid, and were might it of come from?

source: wikipedia

I have circled were I think the liquid came from on the left engine in the picture above.


texts: Why are you not allowed to use power sockets in the seats during takeoff and landings?

texts: Is it because the extra strain on the electrical system reduces engine performance?


texts: Is it possible to get access to flight logs of USAAC trainer planes from the 1930s?

texts:
After answering this question on History.SE, I started to wonder if it would be possible to find out even more detail about the plane now that its serial number is known.

I have no idea what kind of flight records the US Army Air Corps kept, however. I know most flight logs today are kept by pilot, but I imagine there would be some way to trace what pilots flew a particular plane. I have no idea if this is possible for USAAC trainer planes in the 1930s.

Could I get access to these records? If so, how would I go about it?

I'm mostly interested in seeing if I can find out more information about where the plane flew, and maybe (if I'm lucky) who flew it when and for what purpose.


texts: Why are safety demonstrations done while taxiing?

texts:
In airliners, safety demonstrations are performed when the aircraft is leaving the gate. I understand it cannot be done latter as an aircraft incident including an evacuation may occur at take off roll. But I think it could be done earlier (e.g. in waiting area before boarding). This way, if any passenger has any question (e.g. this one), this passenger has plenty of time to ask flight attendants before takeoff. This time may also be used to explain why safety demonstration include all those items (life vest inflated outside the airplane is not the only item that could raise questions). Moreover it could be a good use of waiting time before boarding.

EDIT: As highlighted by one answer, some airliners use video to do this demonstration. In this case, the generic items (i.e. not aircraft specific) of the video could be played on screen in waiting area in addition to the actual briefing.


texts: Why are trailing-edge control surfaces usually split?

texts:
I've noticed on many military and commercial jets, the trailing edge control surfaces (ailerons and flaps) are separate from each other.

Why is this? Can't both serve the same function? It would save weight and complexity if one combined control surface ran the length of the trailing edge, instead of being split in half.

A particular example I found is the F-102 Delta Dagger. There's no conventional tail to experience disrupted airflow, so why have separate ailerons and flaps?

A similar idea that I know exists is the V-tail, such as in the F-117, which has "ruddervators"---combined elevators/rudders. It can still control yaw and pitch at the same time by somehow averaging the deflections. Presumably, combining and averaging ailerons and flaps should be even simpler, since they're both deflecting on the same axis.


texts: Should I connect the AR6203 COM radio to the GMA324 audio panel using symmetric or asymmetric wiring?

texts:
I have this little project to change the Audiopanel and COM to GMA342, GNS430 and Becker AR6203. Airplane is a Piper 28-181.

I would like to know if I have to connect the AR6203 to GMA342 in symmetrical or asymmetrical wiring?
As far as I have researched it, I would say it is symmetric.

Is it a good idea to ground the audio shields at aircraft gnd/power gnd?


texts:
As just a passenger, not a pilot, this may be a very basic question, but when I am on an airplane leaving the terminal, it goes over a symbol on the tarmac that looks like this:

Also I see signs on the side of the runway pointing to those markers.

On a related note, there is a similar sign near the gate that looks like this:

What do these signs mean?


texts: Who's in charge of running VOLMET stations worldwide?

texts: Are the broadcasters private individuals, governments, companies? Are they required to function 24/7 and if they don't, are the owners fined?


texts: Was it ever considered to optimise a jet to normally operate with one engine shut off?

texts:
As I understand it, the current trend to reduce all commercial aircraft to no more than two turbofans has long-relevant reasons – the more engines, the higher the fuel consumption – and earlier jets mostly had to come with more to ensure reliability.
Now, the naïve solution to design an aircraft with 3 or 4 engines but needing only two has obvious economic flaws and a normally mounted engine introduces so much drag that it's certainly always better to run it than not. However it is not unheard that existing aircraft designs were upgraded with better engines (particularly for economic reasons: stern look at 737MAX). I'm thinking particularly of trijets here: the 727 for instance did have its outboard engines upgraded to higher-bypass ones in its career. I could well imagine that they thought about whether the center engine could be made obsolete altogether – just make the new engines 50% more powerful each, and thus degrade the center one to a mere emergency backup. (And do something aerodynamic about the S-duct so it wouldn't be too detrimental for drag anymore.)
Was any such redesign seriously pursued by one of the major manufacturers?


texts: What is the vocabulary used by fighter pilots used to communicate?

texts:
As far as I understand, fighter pilots or more general military aircrews will use a dedicated phraseology to communicate with each other, which is different to communicating to ATC.
Is this phraseology standardized across different air-forces or even within NATO?
Are there any public documents on this phraseology?


texts: How to calculate the radius of a turn as a function of speed, bank, wing-loading, and Cl?

texts:
Although the question of how to calculate the radius of a turn of an aircraft has been answered before using only the speed and the bank angle, the reality is that 2 aircraft with the same speed and bank angle will have a different radius of turn if their wing loading is different.
Furthermore, two aircraft with the same speed, bank angle, and wing loading will not necessarily have the same radius of turn. The lift coefficient of the wing must be taken into account.
Since the answer posted before is not complete, can somebody provide an equation that takes into consideration the above factors (and any others that should be contemplated)?


texts: Can a commercial aircraft theoretically reach 60,000ft?

texts:
As per this question:

Altitudes above 60,000 feet are class E airspace.
That means that, if you are lucky enough to have an aircraft that flies that high, once you get there you could theoretically call ATC, cancel your flight plan and continue VFR above flight level 600 without ATC supervision.
At that point, you are on your own, and out of the system.
You are literally past the edge of human civilization.

If a commercial airliner, such as an A320 kept ascending, could it reach this altitude? If not, what is physically (ignoring legalities) stopping it from doing so?
Since it is not a legal requirement to use ATC at this altitude, perhaps this could be an airspace future budget airlines occupy to save time and therefore money.


texts: What is the reasoning behind using depleted uranium as counterweights in the 747?

texts:
I recently found out that some of the earlier models of 747 had between 600 and 1100lbs of depleted uranium as counterweights. These counterweights were found in 747s manufactured between 1968 and 1981.

(Source)

Given that the study linked above and the well-known radiation exposure for workers (and passengers) even prior to the 1968 introduction of these counterweights, why did Boeing (and McDonnell Douglas) decide to use such a hazardous (and potentially dangerous from a military perspective) material?

I understand that the weight/density allows for a smaller package, but it seems that the tungsten weights were integrated after 1981 without any space issues in existing aircraft.  Was depleted uranium in such high supply that it was also more economical?

Eventually, the counterweights were replaced with these tungsten replacements:

(Source)


texts: Winglets vs Sharklets vs Blended wingtips

texts:
I tried to look for this answer but I was unable to find a complete one.

What is the differences between Winglets, Sharklets (used for example on A350 XWB), and "Blended wingtips" (used only on 787)?

Especially firt two seems very similar. Anyway, more in general, what are differences/PROs/CONs of these different solutions?


texts:
Does a tandem ultralight need flaps on the rear wing if the front wing has flaps?

I understand that most Rutan canards don't have flaps as I was told if the main wing has flaps, the canards need one too.

Rutan did make one with flaps on both the canard and the main wing.  I think it was called the Grizzly.

So... what about a tandem aircraft (with positive lift on the horizontal tail) with flaps on the front wing ? Does the rear wing need flaps too?

Can't you just use the horizontal trim tab as a flap if you need more rear lift to offset extra lift of the main wing with flaps extended?

After all, wouldn't most conventional aircraft with rear cg and slow flight ( low Cm) in a dive with a symmetrical horizontal tail, with elevator down, be generating positive tail lift anyways, so they are acting like a tandem aircraft, no?


texts: In this MD-11 stall test video, are we seeing the tail stalling first?

texts:
Watching this short stall test video for the MD-11, one can notice obvious buffeting (starting at about 0:04) of the tail section, while at the same time – at least apparently – there doesn't seem to be any major buffeting of the wings.
I've also read Why are aircraft designed so that the wing stalls before the tail?
Considering that vision (especially in a degraded old video) isn't a great gauge for what's happening, I thought to ask this question with two related components:

Are we really watching the horizontal stabilizer stalling first?
Either due to a bad design, CG issues, or trim errors, is it possible to have the tail start buffeting before the wing, but not stall before it?


texts: How to proceed in designing a catapult glider with maximum flight distance?

texts:
As a basis for this question, take the following catapult glider:

http://www.guillow.com/spaceshuttle.aspx

This model has low aspect ratio wings, a thick wing section and a relatively wide fuselage, however the surface of the glider is smooth. Is this an optimum design for distance or is there a better design possible?

How will the following parameters affect how well the glider fulfils its requirements?

Weight
Wing area
Wing planform
Fuselage width
Surface roughness
Aspect ratio

(covered here How does chord length affect wing design?)

At least what areas should a designer experiment with in order to achieve long flights?


texts: What is this aircraft with a crew member in an exposed nose compartment?

texts:
Possibly from around 1935, possibly involving one of the two airplane-supplying-powers in the Spanish Civil war.

(Seen in a documentary about the 20th century inter-war era...it's only onscreen for a few frames.)

(It looks like one of the fantastical, almost-plausible air vehicles seen in Ghibli films!)


texts: Does the person directing the plane to parking not risk getting ingested by a jet engine?

texts: According to answers in this post, a jet engine can suck a human into its engines, even on idle power. Aircraft use their engines post landing taxi and into their parking space, and I notice people directing the plane to and from the parking space while engines are on.  Do they not risk getting ingested into the plane's engines?


texts: Benefit of a deswirl vane for a turboshaft helicopter engine

texts: I am trying to understand the benefit of deswirl vanes on a turboshaft helicopter engine. For these type of engines, the kinetic energy of the exhaust stream is essentially wasted energy. Also, raising the static pressure at the exit plane by deswirling will reduce the shaft output power. So, why bother?


texts: Is the airspace at KUGN class G from the surface to 1200' AGL where class E starts when the tower is closed?

texts:
The chart supplement for KUGN here says "AIRSPACE: CLASS D SVC 1200-0200Z other times CLASS E."

Does that mean that when the tower is closed, the class D airspace switches to class E surface area entirely, or is there class G from the surface up to 1200', and class E from 1200 up to 18000'?


texts: Does the retirement age for commercial airline pilots vary across the globe?

texts: Do the retirement age of commercial airlines pilot varies from country to country?


texts: How do wing tip vortices interact with the airflow on an wing with winglets?

texts:
If winglets are added to an aircraft, do the vortices still interact with the airflow and create up wash and down wash. If the vortices do interact with the rest of the flow I am wondering how they do it.

So basically I am asking if wingtip vortices can affect airflow when there are winglets on an aircraft.


texts: Why would a pilot on final to a towered airport not speak up when ATC clears another aircraft to land on the same runway, without mentioning them?

texts:
Every time I watch AOPA's Accident Case Study video Communication Breakdown, I'm left wondering. Here's an aircraft (in this case, '1DA) on final approach for landing on a towered airport, when another aircraft ('4SR) is cleared to enter the traffic pattern, and gets cleared to land before they turn base, without ATC mentioning the aircraft already on final. One could make an argument that the pilot of '4SR should be aware of '1DA, but somehow, they apparently weren't. Once the pilot of '4SR is made aware of the traffic already on final, they make what I can only describe as a hasty attempt at an evasive maneuver which results in '4SR crashing into the ground, killing everyone aboard '4SR.

Yes, this is a towered, controlled airport; ATC should be the one to inform the incoming aircraft about the one on final. But for some (here unimportant) reason, ATC fails to do so.

To make matters worse, '1DA is flown by a student pilot and instructor, so there's two people there, either of whom (and certainly the instructor) can use the radio.

In such a situation, why wouldn't the pilot of '1DA speak up?

'1DA was still some distance out from the airport. It seems to me that besides the obvious of maintaining situational awareness, there were several rather obvious options available here:

No later than when the pilot reported being on base, ATC could (maybe should) have instructed the pilot of '4SR to make a right turn to re-enter the downwind leg, and to then extend downwind and land behind '1DA. Yes, reentering the downwind leg from the inside would be unusual, but it seems as though it would have kept them well out of the path of '1DA on final.
ATC could have told '1DA to go around when the controller realized that '4SR was unaware of '1DA, allowing '4SR to land ahead of '1DA; things could be sorted out once both where on the ground (the video mentions this possibility).
The pilot of '1DA could have made a position report specifying being number one on final for the same runway, when ATC didn't mention them to '4SR.
The pilot of '1DA could have aborted their landing and executed a missed approach, announcing this, effectively letting '4SR land ahead of them.

Any of those (and probably a few other) options seem like it could have prevented the accident altogether, at the cost of a relatively minor inconvenience to either '4SR or '1DA. So why would no one do anything until it was (obviously in retrospect in this particular example case) too late?


texts: Is it legal to fly this approach in Bahrain if the VORTAC is out of service?

texts: Can I fly the VOR/DME/ILS RWY 33R approach at Bahrain/Isa Airbase (OBBS) if the OBBS VORTAC is out of service?


texts: Do airline companies have a Chief Medical Officer?

texts:
I was wondering if airline companies have a Chief Medical Officer who is in charge of the well-being of passengers. For example:

in timing the lights on/off moments on intercontinental flights;
timing and type of food served, to support periods of sleep, wake and disembarcation;
airconditioner procedures, to ensure passenges don't get sick from too cold airconditioners (for example when the captain released power from the engines to the airconditioners after take-off, while the cabin crew had set it to min-min on an insufficient EPU at a hot airfield, it happily started blowing 10 degrees C in my neck);
methods and moments of desinfecting the air/passengers when contagious diseases break-out (or a flu epidemic in the US, with all its internal air-traffel);


texts: What is this helicopter type at a U.S. military base?

texts: This helicopter is on a US military base, shown by Google Maps. I don't recognize the glass windows at the front top.


texts:
I hear the term "compressor stall" when talking about turbine engine difficulties.

What exactly does this mean? And how does a pilot diagnose and fix it - specifically, would there be any changes in the engine instruments compared to normal operation?


texts: Why are there double hinge lines on the rudders of the Grumman C-2?

texts:
Why are there two sets of hinge lines on the rudders of the Grumman C-2?

A photo from the related ASE question Why does the C-2 left inboard stab not have a rudder?
Why would two hinge lines provide more control authority than just using the forward hinge line and deleting the rear one?
And why was it thought worth the extra complexity and weight to use this feature on this aircraft when so few other aircraft have been designed with this feature?
What other aircraft have been designed with this feature?


texts: How can I determine the amount of trim drag?

texts:
I fly an ASW27, which is a 15 meter glider with flaps.  I am flying with the CG at 62% aft.  I use down flaps while in a thermal and climbing; negative (up flaps) are used in cruise between thermals.  typical thermals speed is 50 to 60 kts (with ballast) and 90 to 100 kts in cruise.  This glider has a T tail and I need nose up elevator for thermal and nose down elevator for the cruise.

I notice that in cruise, the elevator is deflected down about 10 deg.  Is that deflection creating a significant amount of drag that could reduce my glide performance?  I have the ability to move the CG by dumping the ballast in the tail tank


texts: What is the relation between the Lift Coefficient and the Angle of Attack?

texts:
I'm trying to understand the relation between the Lift Coefficient and the Angle of Attack using PEP software for the A320 IAE. However, I notice that often for a given Angle of Attack, there could be more than one Lift Coefficient ("slightly different" but different).

Is it an error or a real issue? If yes, what are the standard conditions assumed for the Cl vs AOA graph?


texts: What is the meaning of the crosshatch marking on altimeters?

texts:
What does the crosshatched area on an altimeter tell you?  It's only visible when below 10,000 ft indicated altitude.  Can't be terrain awareness, a lot of terrain around here is over 10,000 feet.

This sample altimeter display from the FAA manual on flight instruments shows the crosshatched area:

Here's the accompanying text from the manual where it points out the crosshatched area:

  Crosshatch flag: A crosshatched area appears on some altimeters when displaying an altitude below 10,000 feet MSL.


texts: Can a commercial pilot decide where to make their turn after departure?

texts: If there aren't published vectors to tell a commercial pilot which heading to take as they climb, can they decide where to make their initial turn on their own or would an ATC always involved in where they make the turn?


texts: I am curious about delta wings. I read some articles and found the term "slender delta". Please help me to understand this term.


texts: Can transition on an airfoil occur without prior separation?

texts:
i.e. can transition occur without the presence of a laminar separation bubble? If yes, what would this look like in a pressure distribution?

Here, a clear laminar separation bubble can be seen.

The Reynolds number has been increased by a factor of 10. The transition point is still visible, but it is not so clear anymore whether there is a separation bubble. Is there a possible scenario where a laminar boundary layer transitions without first separating?

EDIT: I'm not asking about how to force transition in XFoil or in real life (using turbulators), but rather if "pure" transition can occur naturally on an airfoil.


texts: How am I supposed to track to KOSAX on the OLIVI 4W out of EDFM?

texts:
The SID chart for Mannheim, Germany (EDFM) runway 27 has segments to OLIVI are not defined in terms of any navigational aids but simply specify a track.

How am I supposed to fly these accurately? And more to the point, how am I supposed to determine that I'm over KOSAX? Dead reckoning? You might think that the SID requires GPS or other RNAV equipment, but there is another chart for that (which is virtually identical, but uses GPS-fix symbols instead of intersections).

KOSAX is also not shown on the Lower Enroute chart, which might otherwise have helped to determine its location.


texts: Why do we see "page intentionally left blank" so often in aviation related documents?

texts:
In aviation, we see the phrase "This page is intentionally left blank" quite often in documents like POHs, AIP etc. I can't remember seeing this in any other field. Why is that the case? Why do we see it that often in aviation related documents but nowhere else (anymore)?

There is a good answer to a general question about this phrase on UX.SE but I'm wondering specifically about its usage in aviation related contexts, especially in an age where the main distribution channel for documents is digital distribution and not paper anymore.


texts: Why does pitching moment coefficient decrease with an increase in the angle of attack?

texts:
Slope of Cm vs alpha graph is negative, why it is so?
The attached graph is from https://en.m.wikipedia.org/wiki/Pitching_moment , this graph is for cambered airfoil, as pitching moment is zero for symmetrical airfoil, as center of pressure remains constant for symmetrical airfoil.

My question is different from suggested question Should the pitching moment be up or down? as my question is talking about pitching moment coffecient which depend on pitching moment, dynamic pressure, and other parameter.

Cm= M/qSc

Where M is pitching moment, q is dynamic pressure, S is the wing area, c is the length of chord of airfoil. But I am not able to get it correctly how Cm decreases with increases in angel of coffecient. If we see pitching moment value then I think it should increases with increase in angle of attack as centre of pressure shifts away from center of gravity with increase in angle of attack.
 (source: wikipedia)


texts: Do the white lights on the chimneys of the Tokyo area incineration plants serve an aviation purpose?

texts:
At least 新江東清掃工場 (Shinkoto Incineration Plant), 江戸川清掃工場 (Edogawa Incineration Plant) and 市川市 クリーンセンタ (Ichikawa Clean Center) ー blink with white lights in series.

I know that the red lights of other buildings and structures are for air traffic safety.

But these plants are relatively low. Their chimneys have the lights attached. And as said they blink white.

Yet the near port probably has no use for these lights.

I suspect this is for air traffic. Is this some sort of guidance system marking flight vectors or something?


texts: Why did my flight descend for landing then suddenly climb steeply and turn sharply?

texts:
I was flying on a Vueling flight (VLG6251) from Rome, Italy to Orly, France on the 31st of December 2017. During landing, my plane went to a really low altitude as if it was about to land but there was no airport! I mean it was really low, and all of the sudden the plane sped up as if was taking off and it went to really high altitude really fast, while sharply turning to the left! Then I saw the airport. I checked the flight history of that flight and there was no history of it doing that.

Any suggestions on what was happening?


texts: Isn't it the job of the air traffic controller to assign altitudes and make sure airplanes do not collide in mid-air? Is having TCAS mandated or optional? If it is a mandate, then is there a mechanism to notify other airplanes that TCAS is off?


texts: How does a standby ADI remain accurate when flying over the curved earth?

texts: How does a standby attitude directional indicator remain accurate when flying for many hours over the curve of the earth? While maintaining level flight, wouldn’t the pilot see an apparent movement of the attitude indicator in relation to curvature he/she is flying over?


texts:
What material is the B737 wing skin made out of?
I actually couldn't find much information on the wing skin upper and lower panel materials for the B737, the general guess is of course aluminium, but I'm hoping to know specifically what series of aluminium?
The 2000 or the 7000 series? even within these, specifically which one like, Al 7068 or Al 2124?


texts: What airfoil type is used on the B727-200F?

texts: What airfoil type is used on the Boeing 727-200F? Is it a NACA profile or something else?


texts:
What is the main difference between Class C and B Radar Service?

  Class C service provides approved separation between IFR and VFR
  aircraft, and sequencing of VFR aircraft to the primary airport.

  Class B service provides approved separation of aircraft based on IFR, VFR,
  and/or weight, and sequencing of VFR arrivals to the primary
  airport(s).

What does approved mean?


texts:
I understand why we do wing bending tests. Now I want to learn more about the test. How is it performed?

I mean in what conditions, with what equipment and what are we expecting after we perform this test?


texts: To what extent is remuneration under a PPL enforced in the UK?

texts:
I came across this, How do PPL, CPL, and ATPL compare? and was intrigued by the fact that a PPL cannot fly for any payment whatsoever.

To what extent is this enforced?  An example scenario would suggest that, for example, I fly my employer to an exhibition on the continent, which he then claims from the company and privately reimburses me for the hire and landing fees. Alternatively, I receive some kind of company bonus to cover the cost, or even further, he blatantly pays on a company card.

Is this illegal? How could this kind of activity be stopped?


texts: What happens if fuel tanks are hit by gunfire?

texts:
In June 2014, a PIA airplane was targeted by machine gun fire while landing.

I wonder what would had happened if the fuel tanks were hit? An explosion, perhaps?

But in an episode of Myth Busters, they did shot at a gasoline tank and found out it didn't explode. No ignition temperature was reached they said.

So, what would be the worst case scenario if a bullet hits the fuel tank on an airplane?


texts: How airlines are calculating crew member's payroll?

texts:
What methods are used by the airlines to calculate the payroll of a commercial airline crew member?
Does it always depend on the number of flight hours in the period, the number of duty days, or some other metric?


texts: if your Seneca weight is 4000 pounds , and you have 800m visibility, would you take off?

texts:
An examiner asked me if your Seneca weight is 4000 pounds , and you have 800m visibility, would you take off ?
I said by law the visibility is ok but still I would not because if we get an engine failure, We can't maintain VMC or altitude  , but he wants me to explain more and better !??


texts: Are ATC radar tracking records and audio recordings considered legally public?

texts:
In practice, they are simply available online and mostly free.
Alternatively, anyone may purchase an ADS-B receiver to monitor the surrounding air traffic and air-band radio to listen to ATC.

I am wondering if there are regulations, similar to restriction of the use of GPS tracker and phone call recording? Or is it simply assumed that, for public safety, anyone conducting a flight is automatically presumed to volunteer the information of flight path and air conversation to the public?


texts: What is a minimal step angle deflection for flight control surfaces?

texts:
If the flight control surfaces (ailerons, elevators, rudder) are controlled digitally by servo motors, yet disregarding the way how the input to the servo motors get generated (manually or autopilot), what is the suggested minimal single step deflection of the control surface to be of practical value for a large UAV or piloted airplane?

By "practical" I mean not a ridiculously small angle that slows down the servo with unnecessary many steps, yet sensitive enough to allow for a smallest practically useful deflection or ensure the precision of a small input.

If the minimal step of deflection is not the same between them, then please suggest your answer for each control. Please give answer in degrees within 360 circle.


texts:
I hear about Jessica Cox; born without arms, she is the world's first licensed armless pilot.

How can you pilot a plane without arms? How are the controls modified in order to let her fly?

Anyway: great respect for this woman. Absolutely.


texts:
« A fume event occurs when bleed air used for cabin pressurization and
  air conditioning in a pressurized aircraft is contaminated by fluids
  such as engine oil, hydraulic fluid, anti-icing fluid, and other
  potentially hazardous chemicals. » (source)

Wikipedia does not explain how and why a fume event can occur, but notes:

  « The cabin is pressurized with bleed air tapped from the jet engine's
  compressor sections, which are prior to the combustion sections. » (source)

Question:

(1) status quo
Given that bleed air is tapped at an early stage before coming into contact with fuel and thus cannot come into contact with fuel, why then can it come into contact with the other fluids quoted above ?

(2) solution?
To avoid any potential contact with these fluids, couldn't it be tapped an an even earlier stage (in the front section of the engine) or rerouted/transported differently from the engine into the cabin? Isn't there any solution (other than bleedless aircraft) to eliminate the potential for both fume events (acute exposure) and long-term health effects (chronic exposure) for the cabin-crew and frequent flyers due to long-term exposure to minimal doses ?


texts: May pilots perform FMS database updates under Part 135?

texts: Are pilots allowed to perform FMS database updates under part 135?  If so, do they need formal training entered in their pilot records before they are allowed to do it?


texts: Which aircraft have elevators (lifts)? How do they work?

texts:
This Question came up reading this comment from  tohecz on this question: Is it possible to access the baggage compartment in flight?.

  No elevator to the cargo deck like in thriller movies? I'm disappointed :( /sarcasm

According to some statements on Internet, there are elevators(lifts) on 747s for persons and carts.

Does anybody have any evidence or photos of their existence on smaller planes than A380s?
How do they work?
Do they have an electric-motor department on top (This will take much space)?
Where are they going to? Are they going to the personnel sleeping cabin? (On the A380 it makes sense)

This one from a A380 doesn't seem for persons?


texts: Blunt noses subsonic drag - why a complete ellipse?

texts:
At subsonic speeds, blunt noses - both fuselage and airfoil - are good for two reasons:

the need to maintain attached flow at varying angles of attack.
it has less surface area for the volume, reducing skin friction.

TOP: 0 AoA/Cruise
| BOTTOM: extreme AoA, 20-30degrees, takeoff/landing

If the airflow had to flow over a ridge/point in scenario 2, instead of the smooth curve, flow separation would be more likely.

But things don't seem to add up.

Firstly, it's not like most airplanes - particularly airliners - fly at AoA beyond 20-30 degrees. At least not without high-lift devices. Am I correct? But on the rounded nose, there are surfaces smoothly curving all the way from 90 degrees! This seems to me like a useless increase in cruise drag.

Secondly, why push a blunt face ahead of you just to increase the volume a little, whem you can use a curve terminating at a point/ridge, as will be demonstrated below? If the surface area to volume ratio becomes so important, we can just sacrifice the fineness ratio and still have less drag, as the new nose creates less drag, right?

Would limiting the curvature to the max AoA limit for the aircraft, then terminating at a point, as in the image below, not keep the flow attached throughout the expected AoA range, while producing less drag? At the maximum AoA, the flow over the top of the shape encounters no "ridge" or "point", as it is parallel to the half-angle at the nose.

TOP: less drag is created at cruise
| BOTTOM: Flow remains attached at extreme AoA conditions.

What am I missing about the sharp nose? How and how much does it hurt performance? Why, after all this seemingly shown in the question, is it - aside from the radar - that big planes have round noses?

In short: I am claiming that an elliptical nose tipped with a triangle or cone of 20-30 degrees half-angle should be better than a pure ellipse for subsonic aircraft. Why am I wrong?


texts: How can the F-15 and Su-27 achieve a high top speed without variable wing geometry?

texts:
I watched a documentary once that explained, I believe, how the Su-27 and similar aircraft such as the F-15, can achieve a high top speed without variable wing geometry.

How does this work? How do they achieve high performance without swept wings in the F-15, Su-27, and similar aircraft?


texts: What do professional commercial pilots do to counteract boredom?

texts:
With the eyes of a layman, it seems to be a wonderful thing to fly a big airplane between continents. From an initial perspective anyway.

During a transatlantic fight, pilots can see the water of the ocean, and the never changing readouts in the cockpit. Years long. Decades long. Only the water, the clouds, the sky, the sun and the sensor readings.

Until they retire!

Ok, maybe they could get a laptop with them and play on that, but I think it is probably against the rules.

Isn't it something like a prison for life? How pilots deal with the increasing boredom?


texts: If a pilot has the wrong altimeter setting, will his transponder mode C altitude be off too?

texts: Just wondering if the transponder mode C reported altitude will be off if the pilot accidentally has the wrong altimeter setting.


texts: Is "excess thrust" possible in a steady state vector diagram?

texts:
Being recently very much sold on the lift-weight-thrust closed triangle (with weight forming the hypotenuse) model for climbing flight, I proceeded to put the logic through its paces (validation) and got stuck on one fairly basic concept:  excess thrust may be only transient.
Increasing throttle increases speed.  We can initiate a climb with more speed, thrust working against increased drag, and to hold the climb against the tilted lift vector by increasing the lift coefficient, by way of increasing AOA.
Note the with a GA aircraft (25% max thrust to lift), increasing AOA excessively leads to loss of airspeed.  In fact, this is how to stall an aircraft.
Pitch can never be transitioned into hover before stalling.
Can anyone confirm that, beyond applying throttle before the takeoff roll, "excess thrust" exists at all?


texts: What does induced flow exactly means on helicopters flight? How is it different from downward deflection of air?

texts:
I believe all airfoils deflect air downwards at an angle at a velocity V. What is the difference between the downward-vertical component of the deflected wind and the induced velocity in Helicopter flight?

Corollary: Why the airplane doesn't face this induced velocity and induced drag?


texts: turboprop thrust relative to the jet's propulsion

texts: What is the thrust ratio in a turboprop between propeller and its jet exhaust, and is the jet exhaust necessary for flight? Once the turbines are spinning, it seems the exhaust is waste product. This would be inefficient and could be used for more power. Is this so?


texts: I want to take some pictures of a bridge. How close can my pilot get me?


texts: Isn't it dangerous for a soldier to sit on the outside of a flying helicopter?

texts:
AH-64 during an extraction exercise at Camp Bondsteel, Kosovo in 2007 with a soldier on the avionics bay.

I lit upon this image on Wikipedia. I see that the soldier is harnessed fastened to the helicopter, but what if the harness tears? What if the soldier falls? Or if he gets sucked into the helicopter engine intake?


texts:
The General Electric CF34 high-bypass turbofan (used primarily on the Bombardier CRJ and Embraer E-Jet regional jets), unlike the vast majority of jet engines (both civil and military), is not certified to burn so-called “wide-cut” fuels (gasoline-kerosene blends, nowadays used mainly in cold-weather operations), such as Jet B1 and (formerly) JP-3 - only “narrow-cut” fuels (straight kerosenes), such as Jet A-1,2 Jet A, JP-5, and (formerly) JP-1.  In contrast, CF34s in military service (known to the military as the TF34, and used mainly on the A-10 ground-attack aircraft) do just fine with wide-cut fuels (an absolute necessity back when aircraft so engined entered military service, as the go-to military jet fuel back then was JP-4, aka Jet B with the military’s stamp of approval).

This is a bit surprising, as:

it renders CF34-equipped aircraft unable to operate in very cold places (wide-cut fuels, having much lower freezing points and viscosities than the straight kerosenes, remain useable down to much lower temperatures than their narrow-cut ilk), and
there doesn’t seem to be any obvious technical reason for such a restriction, seeing how, as mentioned above, military CF34s are perfectly happy to run on wide-cut fuel.

Is there some critical difference between the military and civilian versions of the CF34 that renders wide-cut fuels compatible with the former but not the latter (maybe a gasket somewhere in the civilian CF34 that’s dissolved by the gasoline in wide-cut fuels?), or did General Electric simply not bother to certify the civilian version for use with wide-cut fuels?

1: Formerly also often known as “JP-4”.

2: Also often known as “JP-8”.


texts: Would it be possible to build an engine twice the size of the Trent 900?

texts:
Would it be possible to build an engine twice the size of the Trent 900 in terms of physical size, i.e. doubling the diameter?

Let's assume that it's feasible to build an aircraft tall enough to install the engines. I will go on to ask about the extra heat at the engine core or hot sections of the engines but to run such an engine, would current materials be able to tolerate the extra heat? Would the larger fans tolerate the extra stresses if the diameter doubled?


texts:
I found this image on boldmethod.
Where is this? Looks like a beautiful place. Has an instrument approach (from the runway markings.) On a mesa in snow country. It is not Sedona or St George.
Telluride?


texts: Why do the Cirrus SR-20 and SR-22 have the CAPS (parachute) system?

texts:
Cirrus touts the parachute as an added layer of safety. The parachute has obvious marketing value, but is the parachute's added safety a spin on the airframe's shortcomings? CAPS is not an option when buying a Cirrus, so what's the real reason for it?

Why do the Cirrus SR-20 and SR-22 have the CAPS parachute? Can a Cirrus SR-20 or SR-22 be certified to fly without it?


texts: Is it possible to use reverse thrust while airborne?

texts:
I play a flight-sim called X Plane. The other day while I was approaching an airport a little too fast and knew I couldn't slow down in time. I decided to use the reverse thrust while I was still in the air and this helped dramatically and I was able to land safely.

But now I'm curious - Would using reverse thrust in a real-life Boeing 747 have the same effect, would it cause the plane to crash, or go out of control?


texts:
This subject keeps coming up in the discussions and questions such as this one, which asks if lift equals weight in level flight. Good answers there, pointing out that upwards force has many sources. But also some that need clarification.

It is also mentioned at several places on this Aviation SE site, in question & comments, that lift always equals weight if the aeroplane is not accelerating upwards or downwards, since only an acceleration requires extra force according to Newton.
With zero wind, lift is always defined as the force perpendicular to the flight path, but gravity does not tilt with the aircraft axes. My question therefore is also about the sum of all vertical forces: in a steady climb, is the total upwards vertical force from all sources (wing, tail, engines, fuselage) larger than, or equal to the weight of the aircraft.

If larger: please quantify.
If equal: please explain why.

Addition
An answer.


texts:
I have a question about a document published by the Association of European Airliners. The name of the document is “Long Range Aircraft - AEA Requirements.” In the Appendix titled "Definitions and Inputs for Range and DOC Calculation," paragraph 1.1 (“Flight Profile for DOC and Range Calculation”) at Note c) we can read the following recommendation:

  Cruise, and completion of step, shall be at that altitude at which the potential rate of climb, at initial cruise weight-climb speed, is 500 ft./min or more

I don't understand the meaning of that sentence. What’s the definition of “weight-climb speed?”


texts: What is the relationship between the terms "airprox" and "near mid-air collision"?

texts: Do the terms "Airprox" and "Near mid-air collision" mean the same? If not what is the difference between them?


texts: Could the Shuttle Carrier Aircraft do a transatlantic flight with a Space Shuttle orbiter on its back?

texts:
Some of the STS backup landing sites were in Europe.

Of course, The STS would actually have to fly there only in case of extreme emergency, so the number one priority was just to save the lives of the crew members.

However, did NASA have a plan, or would it be doable to airlift the Space Shuttle atop an the Shuttle Carrier Aircraft like on this picture?

I'm especially curious about the range penalty induced by the additional drag of piggybacking the orbiter.

Picture credits: NASA / Carla Thomas, Public domain.


texts: What does Top 1% mentioned by ATC refer to?

texts:
I have watched Live ATC tons of time. But I still don't know which airline is called "Top 1%". Ex: Delta 81 right Bravo right Kilo give way to company A380 and follow the Top 1%".

Just wanna know what "Top 1%" means. Or that is only for JFK?


texts: What's the process for an uncontrolled airfield to become controlled/towered?

texts:
I know some uncontrolled airports can have more operations per day than many controlled airports. That got me wondering what the process is for the change to a towered, controlled airport. I know a control tower was recently built (2005) at Provo, UT (KPVU) which is the second busiest airport in Utah.

Is there simply a threshold of average operations/day? Do the number of accidents and incidents come into play?
Does the FAA start the process or does the community have to lobby for the tower?
Who pays for the tower, is it all federal FAA funds or does the state and city where the airport is located pay?
Are there any US airports where towers are being built or considered? Given the recent sequestration and how close we came to having over 100 towers shut down, I'm guessing any current plans are on hold.


texts: What is the maximum rate of descent in an instrument approach?

texts: What is the maximum rate of descent approved in an instrument approach procedure non-precision? Basically what is the maximum rate of descent (Fpm) that I use during the approach?


texts: Are transport gliders used by modern armies?

texts:
Famous WW2 operations involved transport gliders, for troops landing and vehicles transportation behind front lines. Gliders were cheap and quiet aircraft. The advantage over individual parachutes were landings grouped in a smaller area, allowing troops to be quickly operational.

XCG-16 assault glider, source: Retro-Mechanix

Browsing online seems to show an absence of gliders in the modern era. Are there any military (transport/troop) gliders in use in modern armies?


texts: What is the meaning of these Lido abbreviations?

texts:
Can someone help with the abbreviations and meaning from Lido flight planning:

RCONT 5 MIN
HLDDST
ADDT

For each of these abbreviations, the flight plan has fuel and time:

I placed a red rectangle around the abbreviations; I Hold Distance is ok, however I still o not understand RCONT


texts: What is the ICAO equivalent of /G in a flight plan?

texts: How should I fill out an ICAO flight plan if I have a Garmin GNS-430W WAAS certified unit? I file as /G in the US domestic format.


texts: How to identify transmit labels for a particular equipment in ARINC429?

texts:
As i can see, each equipment has a set of labels which the equipment may supposed to be received. Say if i am Equipment 03Ch (Tire pressure monitoring system), i will be configured to receive below labels
LABEL 060 -> Tire pressure (Left Outer)
LABEL 061 -> Tire pressure (Left Inner)
LABEL 062 -> Tire pressure (Right Inner)
LABEL 063 -> Tire pressure (Right Outer)
LABEL 064 -> Tire pressure (Nose)
But how may i know, what are the labels should i send ?


texts: What does "CC (Charlie Charlie)" mean when pilots reply to ATC?

texts:
I heard a pilot replied "CC" to ATC instruction.

I can't remember the exact situation, but does anyone knows what it means?


texts: What do flight attendants do if a passenger asks what is going on in case of a potential emergency?

texts:
This is related to, but not the same as, another question I asked on Interpersonal Skills.

I was on a flight last year, on a route I fly on a fairly frequent basis. Shortly after takeoff, I heard the three double chime signal, which is commonly used by airlines to indicate to the crew of a potential problem. The crew quickly marched up to the front of the passenger cabin and was briefed by the pilots. I also noticed that the plane was going off course. Some time later, I used the onboard Wi-Fi service to query an online flight tracker about the flight I was on, and it said we were diverting back to our origin airport.

Throughout the whole incident, all the crew kept quiet about the whole thing, and didn't let passengers know about the diversion until just a few minutes before landing back at the origin airport.

Before the announcement, while the seat belt sign was turned off and while the crew weren't making any emergency preparations of any sort (just casually chatting with other passengers), I got up and asked the crew what was going on, and they said "nothing". I then showed them the tracker page which indicated the diversion, and they just asked me to return to my seat.

What's the general protocol for cabin crew, when asked by passengers who notice potential issues like this and get curious? Is it common for them to simply say that "nothing" is going on until the flight deck makes an announcement? What if a passenger really insists on knowing what's going on? (As an aviation enthusiast, I feel more comfortable if told about the issue; not knowing about it can make me feel tensed.)


texts: How do civilian pilots and ATC verify that other people on the radio are who they claim to be?

texts:
I am interested in authentication - how identity is verified - in civilian aviation radio transmissions. I know that when someone is speaking on the radio he tells his call sign. But is there any other system that verifies the identity of the person speaking besides just the call sign that he claims to have?

I am interested not only in how ground ATC verifies which aircraft is speaking, but also in how aircraft ensure that they are speaking to a real ATC facility.


texts: How does traffic handoff between ZMA and Cuba work?

texts:
Cuba and the US have long had "frosty" relations.
With some limited easing of restrictions, there are now direct flights between Miami, FL (controlled by ZMA) and Havana, Cuba.

Does Cuba have an ARTCC?  Do they coordinate with ZMA for passing off flights?Has this been an ongoing system even before the recent easing of sanctions, or is it relatively new?


texts: What does "Constant wind condition during flight" mean?

texts: What is constant wind condition during flight? Is it zero wind velocity at an instant (say at level flight) or wind with constant speed, say 20 m/sec (at steady level flight or whatever it is) Which statement is correct?


texts: How is that there is no leak through the fuel vents during aerobatics maneuvers?

texts:
Can anyone tell me how aircraft such as jet fighters and stunt planes design the fuel tank vent system to prevent fuel leaking through the vents when performing aerobatics, 360 flips and complex maneuvers?
Surely jet fighters don't just let it leak out?


texts: What is the difference between a fix, a waypoint and an intersection?

texts: It seems these terms are used interchangeably. Are they the same thing? Do they all refer to the points in space that are given 5-letter names?


texts: What would happen if the blades of a variable pitch prop did not all have the same pitch?

texts:
What would happen if one or more of the blades (but not all) on a variable pitch prop would not tilt at the same angle as the other ones?

Could this situation happen or is the technology so advanced or stable that it would be basically impossible?

Should it happen, besides vibration (most probably due to imbalance factors,) what other effect could there be? How would pilots solve this emergency (if it can be called so?)


texts: Why does the N1 on a FJ 44-2A turbofan go to 104.4%?

texts:
Whilst watching a video of a Beechcraft Premier A1 Jet whilst in the cruise at FL330 I noticed the N1 on both engines were at 104.4%.

Can anyone explain why they can go over 100%?


texts: Reduction in Service Ceiling / Change in RVSM

texts:
I did some research and minimum vertical separation used to be 2000ft but it changed to 1000ft in 2002 and they want to change it to 500ft on american territory. Is this correct? Why they wouldn't change it to 500ft on European territory also ?

2nd question:if aviation is evolving yearly, then airspace is getting more and more crowded. there is Concorde who has retired but used to fly at 60.000ft for example, why instead of designing new aircraft to fly higher, they would reduce the service ceiling ? I heard that from an engineer but I don't find an explanation. Statistically, they are reducing the service ceiling. Can anyone give an opinion? example? Thanks.


texts: How to check if (small) aircraft's radio is working properly?

texts:
Is there a standard way to test/check aircraft's radio without calling anybody (Ground/Tower) to see if it is receiving and transmitting?

Is there a way to check aircraft radio with your own handheld radio on the ground before takeoff? I am referring to small aircraft type like Cessna 172.