texts: How to perform a "first principle" performance calculation?

texts:
I am a PhD student on flight dynamics and control. This week I was given an assignment to do some research on methods of aircraft performance calculation. After some search on the Internet, I found that traditional methods depended on tabulated data on the airplane flight manual (APM), and about a decade ago, both Boeing and Airbus started to do performance calculation using "first principle" method.

I read on an Advisory Circular document that provides a definiton of this method:

  A calculation using basic parameters such as lift, drag, power or thrust, etc. with the equations of motion. (AC No: 25.1581-1, Change 1.)

And an Airbus document gives some explanation on this method:

  The next step in the performance calculation process, referred to as OCTOPUS (Operational and Certified Takeoff and landing Universal Software), not only offers the same advantages as TLC but also drastically changes the performance calculation method. It is no longer based on pre-computed data, but uses the “first principle” mode that allows a real on-time computation to benefit from a higher takeoff weight. Instead of smoothed pre-computed performance results, the OCTOPUS performance database contains all the airplane and engine characteristics, enabling performance computation based on physics equations. In addition, OCTOPUS introduces a new and improved takeoff chart format, with its use of multi-configurations and influences. ("Getting to Grips with Aircraft Performance", Airbus)

However, I have not found any paper or report on this topic. Is there anybody out there who could help by offering some details of this method, or, providing some references?


texts: What are those little rods that stick out of a planes fuselage?

texts:
I noticed quite a few of them around the nose and cockpit area of a plane when I was at the airport and wondered what they were for, could someone please help.
THERE'S A PHOTO BELOW.

Thanks


texts: Why didn’t the Me 163 experience the serious handling problems suffered by other similarly-designed semitailless aircraft?

texts:
Although the Messerschmitt Me 163 rocket-powered interceptor had a number of frequently-lethal features (its extremely-toxic, violently-reactive, enthusiastically-explosive hypergolic propellants; its few-minutes-brief endurance in powered flight, allowing enemy fighters to wait and then pounce on it as it glided home; its skid landing gear, which rendered it an immobile sitting duck upon landing until it could be towed to safety), its handling characteristics were not one of these; despite its unusual semitailless design (a vertical tail, but no separate horizontal tail), it was extremely docile at both low and high speeds (despite its excellent manoeuvrability, something more usually found in conjunction with very un-docile handling), being difficult to stall or spin even deliberately and showing no untoward changes in stability characteristics even at very high speed.
In contrast, other similarly-configured semitailless aircraft (DH 108, X-4, F7U) were uniformly beasts to fly, being prone to severe pitch oscillations at high speed, yaw and roll oscillations as well at slightly higher speeds, and generally poor handling characteristics overall.
What kept the Me 163 free of the handling difficulties that plagued all those other semitailless aircraft?


texts: Is there a list of aircraft which squawked 7700?

texts: Is there an accurate and updated list of aircraft which squawked 7700?


texts: What plane cost less per mile to operate for one person?

texts:
The 98 Toyota Corolla has a strong history for being a low maintenance, fuel efficient and cheap car. 400k mile reliability if driven with respect and preventative maintenance.
What plane has these qualities with at least a 450 mile range? So I can fly back and forth to flight school instead of driving.
I am sure there are many that will fit the bill but I am looking something for beginners and the cheapest way to fly myself.
Second Scenario: Suppose only using the basic maintenance, without anything more than an oil/filter etc., which plane would last the longest. Obviously simpler plans require less money per nautical mile; of those which would last the longest?


texts: Can I fly with an airband receiver in the United States?

texts:
I'm flying with American Airlines on a cross-country flight soon and was thinking about bringing along my airband receiver/scanner since it'd be fun to listen to ATC.

It looks like I'd be unable to use it during the flight since any type of radio isn't allowed. I don't see any TSA restrictions on them. Am I safe in assuming that I can bring it along and listen to it in the airport terminal without any trouble with security?


texts: Is it legal for a crop duster to fly right over my house while spraying?

texts: A crop duster is flying directly over my house while spraying. I can see the mist coming out while I am standing in the middle of my yard (6 acres). Is this legal?


texts: What is the expected time frame for FAA knowledge test results to show up in IACRA?

texts:
I just passed my Part 107 Remote Pilot's knowledge test this morning, and I noticed that IACRA indicates it may take up to 48 hours for the test records to show up.  Does it always take 48 hours or is it sometimes faster than that?  What is the soonest that I might reasonably expect the test results to appear?

Bonus points if anyone knows why it takes so long, but I realize that may not be something anyone knows about (or can talk about).


texts: Is it allowed to exit the runway by opposites High Speed Taxiway?

texts: Is it allowed to exit the runway on a High Speed Taxiway to the opposite side? (see red line in image below). Assume the situation allows it, like airplane limits, airport congestion, weather, etc.


texts: Why does the P-51 Mustang takes so much altitude to recover from a spin?

texts:
From this answer, it appears that the P-51 Mustang takes a lot of altitude to recover from a spin. The average is a 3000 feet to 6000 feet loss, with a loss of up to 7500 feet in one instance.

The recovery also seems lengthy. From the document quoted in the answer:

  The average spin [...] requiring 3-1/2 turns for recovery.

What makes the P-51 Mustang so difficult to recover from a spin?


texts: What are ATC-side procedures to handle a jammed frequency?

texts:
A few days ago, I was flying into my base airport in the USA with a control tower, and something/someone was jamming the frequency with what the tower thought was a hot mic after I had established communications and received instructions.

They thought it was us with a hot mic (Spoiler: It wasn't), and they managed to somehow broadcast through the hot mic tying up the frequency.

Luckily, that tower operates on two frequencies, so I changed over to the other one and managed to get back in contact with the tower and continued in to the airport; I made sure they knew that we were not the cause of the frequency jam.  That was clear, since nothing was jammed when we changed to the other frequency, plus the original frequency continued to remain jammed.

When such a situation as I describe above happens, what are the procedures that ATC controllers have to follow, and how did they manage to transmit through the hot mic like they did?


texts: How is altitude correlated with true airspeed?

texts:
I am trying to understand the BADA 3.0 dataset (specifically I am looking at Performance Summary Tables):

E.g.

What is not obvious to me is why those tables mention only single TAS for specific FL.

Is it true that for a given specific aircraft there is a single specific TAS that aircraft can travel on given FL (due to wings lift forces produced, etc)?

I thought aircraft are capable of traveling with a range of speeds at given altitude depending on Angle of Attack (AOA).

Or maybe what I am looking at is just a summary table that does not cover all possible values, however, those are the only one FL+TAS pairs that makes sense in practice (as flying otherwise would be highly inefficient).


texts:
Suppose that one points a laser beam to the sky, constantly (so that an aircraft have to deal with it).

Could that beam cause any trouble to that aircraft?

Would that individual need to obtain some sort of authorization?


texts: does a semi sphere have more drag in comparison to a flat plane with equal surface area?

texts: What the title says, some things to know is that these aren't solid shapes, think of a bowl and a sheet of wood.


texts: USA: Why don't airports raise landing fees to make up for low passenger fees?

texts:
A question from travel.stackexchange.com about luggage carts prompted a discussion on the economics of airports. The gist was:

American airports have much lower passenger service fees which
 are capped at USD4.50 per FAA rules than foreign airports, which can easily be USD20-50 per person. This results in much
 lower number of amenities at American airports compared to other international airports.

You’d think they’d try to make it back with landing fees.  But Tokyo Narita airport’s landing fee is JPY1550-2000 yen per tonne. A 787-8 has a weight of 172 t so the fee would be ¥258,000 - ¥344,000 or so or roughly USD2300 - USD3100. San Francisco SFO’s landing fee is USD5.54 per thousand pounds. A 787-8 landing weight is 379,200 pounds so the landing fee is around USD2100. There doesn’t appear to be a significant delta here to account for the difference in passenger fees.

My question is: Why don't airports simply increase the landing fees to compensate for the lower per-passenger fees?


texts:
If an IR device, such as a tracking FLIR system (not a heat-seeking missile), tracks an aircraft and that said aircraft would launch flares. Is the IR tracking device likely to be confused by the flares?

Obviously, the point of defensive flares is to decoy missiles. I want to know if other IR devices tend to be as fooled as a missile.


texts: What is this part on a Cessna 172 engine?

texts: Can any one tell me what this tube with the red is? This is a photo of a 1977 Cessna 172 engine. Looks like the tube is directly connected to the top of the crankshaft.


texts:
Say one wanted to buy a retired F-14, or F-5, or a BAE Hawk. Could I do it?

Obviously this would mean stripping out radars, weapons, rwr, and any other sensitive equipment, but after this, would it be possible?

Is there some kind of procedure for this?

EDIT: What is the typical way aircraft are released for sale? Is it common?


texts: Is there a special kind of fuel needed to obtain high efficiency engines?

texts: Are there any special kinds of fuels that manufacturers are considering in order to make high performance, high efficiency jet engines?


texts: Where can I find this transonic prop airfoil?

texts:
I am interested in identifying this prop airfoil due to its uncommon high .92% efficiency (the best metal props are closer to 83-87%). I have done an exhaustive search for it. It is labeled "NACA RML 9 G 06a". I do not know where I originally got this plot and therefore have no way to know what "ref 3" is.

It does not appear to be a airfoil number and a google search doe not return any "NACA RML" however I have a library of about 2000 "NACA RM" which refers to NACA Research Memos; perhaps the additional "L" means "Letter(s)".

I can find NACA reports starting with "RM G-10" but no G-9. I have also searched for derivatives of "06a" in an airfoil number. I would appreciate any assistance in identifying this airfoil.


texts: How to determine Center of Gravity of the airplane parts?

texts:
I am building a small-medium sized airplane.
Is it possible to calculate "C.G" of each part of the airplane? If yes, How?
Parts: Wings, Tail, Fuselage, Propeller(?)


texts: What are the costs versus benefits of takeoff/landing on grass versus pavement in a light aircraft?

texts:
This question stated that landing on pavement is hard on tires compared to grass, however I don't necessarily agree with that. Even if it is true the impact on the gear and other components may outweigh the benefits to the tires. This leads to the question of what is overall lower cost for takeoff and/or landing from a maintenance perspective, grass or pavement? If that cannot be determined what are the costs and benefits of each?

This question needs limits in order to avoid being too broad, so please assume these conditions:

A tricycle gear airplane that can use either surface like a PA-28, Cessna 152/172, not something like a Mooney which is less grass friendly
The grass surface is in reasonable shape
Accident/incident costs are out of scope for the question


texts: Why are pilots asked to provide a reason for a go-around?

texts: Why does the tower ask pilots what the reason is for a go-around? This seems to be standard for commercial flights.


texts: Can a low flying jet fighter lift water?

texts:
Can a low flying but super fast jet spray water from the surface of the ocean?

I've seen this visual effect done many times in movies. It's often done to highlight supersonic speed just a few feet above the water.

Do the laws of physics even come close to this being plausible?

Bonus: Can you provide photograph evidence of this happening?


texts: Why don't we have video recording of runways takeoffs/landings?

texts:
When planes crash at airports, it seems the only video available is amateur footage several miles away with terrible quality.

Why don't we have video recordings of all takeoffs and landings at the airport?


texts: When might a pilot hand-fly a jet at cruise altitudes, and is it difficult?

texts:
How difficult is it to hand-fly a jet at cruise altitudes? Other than autopilot failure and just doing it for the fun of it, when might you want to hand-fly at those altitudes?

I suspect the answer to the first question varies with different aircraft. I have an answer for the 747-100 and -200 series below.


texts: What's the meaning of underlined frequency in sectional chart nav aid box?

texts:
There is a statement to describe the underlined frequency in legend, it says:

  Underline indicates no voice on this frequency.

What does this mean? We still need to ident the Morse code, doesn't it? So what's the "no voice" referring to?


texts: Why do wind tunnels not have oval turns?

texts:
Why do wind tunnel not have oval turns to reduce energy which is lost in sharp 90 degree turns and decrease turbulence?
Wind tunnel with oval turns:

Wind tunnel with 90 degree turns:


texts: Is it illegal to partially block the aisle on a passenger airliner?

texts: After reading all the commotion about the dog that died after its carrier was placed in the overhead bin I wondered- is it against any FAA regulations to allow a flight to take off with a partially blocked aisle?


texts: Why don't aeroplanes use propellers with more blades like the intake on a fanjet?

texts:
The air intake on a fanjet typically has many small angled blades. A wind pump in an American film might have many broad slatted blades. My desk fan has 3 very large scooping blades and seems quite effective.

It seems to me that if each blade provides thrust, the more blades you have, the more thrust you might expect. It also seems to me that a propeller with more blades could be smaller and turn more slowly, potentially avoiding going supersonic while providing the same level of thrust.

I ask because I'm building a drone and considering using six small multibladed props.

What are the downsides of adding more blades to propellers?


texts:
Let's say that a package has to travel from point A to point B. These places are not located in the same Country, nor are such Countries adjacent to each other. Example: point A is in Italy, point B is in the United Kingdom.

The package is not delivered directly. From tracking info made available by the Company, you find out the package leaves point A and reaches Rome. Then it reaches Bologna, and later Dusseldorf, Germany. It then reaches Barking, in the United Kingdom. From here, it reaches Tamworth and then gets delivered to point B. These legs are pretty short, if you map them, so my question is:

could the package have traveled by air in any of such legs? or do Cargo companies prefer other means in this situation?

EDIT

I am not referring to the use of wide body aircraft on short-haul. Rather, I want to figure out if contracting out the delivery of goods over short-haul routes is a common practice among Cargo airlines. If this is true, how could a given package remain within the network of the Company?


texts: Why does the length of the 737 vary so much?

texts: The longest version is almost 50% longer than the shortest, and even within the "next generation" models, the difference is almost 40%.  Why such a big difference in lengths?


texts: Ambiguous mention of NAVAIDs with duplicate names in FAA's CIFP file (ARINC-424 18 format)

texts:
I am studying FAA's Coded Instrument Flight Procedures (CIFP) dataset (link), coded in ARINC-424 18 format, and I noticed that navaids are coded for the purposes of an IFP simulation only by their short name. The problem is, a number of navaids have duplicate names.

Take, for example, this sample from CIFP, describing ELMAA3 departure procedure:

It's impossible to distinguish if the VI leg during this departure procedure has to intercept a course beginning from either SEA VORTAC or SEA VOT. Both are near the airport but significantly far from each other.

Am I missing something? Perhaps only certain types of navaids are used? Could someone point me in the right direction?


texts: Why are only captains allowed to taxi the aircraft?

texts: At most airlines, only the captains are allowed to taxi the aircraft (i.e. Lufthansa). Even if the copilot is pilot flying, the captain will taxi the aircraft to the runway, and later from the runway to the gate. What is the reason for letting only captains taxi the aircraft?


texts: Why is the B737 altitude display unneccessarily ambiguous?

texts:
I was playing FSX again lately and was flying the B737-400. So I hope it is simulated correctly and this question isn't dead on arrival :-)

It always bugged me, that the altitude display on the MFD is very ambiguous when you are immediately below a "round" value:

On first glance everyone (ok..me) would read the altitude to be 9900 ft. Only if you know what to look for and spot that the numbers carry on downwards you can deduce that you are actually at 10000. The reason is that the second significant digit does not roll over smoothly but ticks over appruptly when the next round value is surpassed.

Granted, 100 ft may not be a huge difference, but it seems very unneccessary to have it like that. If the first two significant digits behaved more smoothly without this round-down like behavior I would recon that it would be way less ambiguous.

Why is the altitude display designed that way?

Edit: Here is what it looks like in motion:


texts:
I saw a video demonstrating the SU-30's thrust vectoring nozzles and noticed that the horizontal stabilizers begin moving up/down before the nozzles do. It seems that the F-22 also has this delay.
Then, after it's in an upright/downright position, if the pilot brings the stick back to center, both the nozzles and the stabilizers move at the same time. This leads me to believe that this is probably not some mechanical lag that causes it. So, why is there that initial delay?
SU-30:

F-22:

Photo demonstrating this delay (note how the nozzles only begin moving some milliseconds after the stabilizer starts moving):


texts:
I want to start out by saying these questions will make me look a fool but i simply haven't found answers for them anywhere so i'm hoping you could help me!

What is the purpose of bypass ducts? If the air is going around the turbine then what even is the point? Why not just make jet engines simple consisting only of the turbine and skip out on the bypass duct?
What makes the fan blades in a jet engine keep spinning? I know how they are started but what keeps the blades constantly spinning with enough inertia to keep compressing air? Is there like a small motor connected to the fan blades via a crankshaft or is a portion of bleed air used to keep the blades in motion?

Thanks in advance for answering my questions :)


texts: What airport fees are charged to airlines in the case of operations following an unscheduled landing?

texts:
A plane may need make an unscheduled landing in the case of a diversion due to mechanical difficulties, unexpected weather, a medical emergency or other reasons (this could even be at an airport with which the operator has no prior agreements).

Airport operators agree various fees with the airlines that use them for their scheduled operations:

runway/landing fees
fees for stairs, buses to the terminal building, or airbridges
passenger charges, should the passengers need to disembark
parking fees
...amongst others

Which of these charges are typically levied in the case of an unscheduled landing caused by unforeseen circumstances?


texts: Is FAA approval required in order to fly an RNAV SID/STAR for a private aircraft operated under FAR Part 91?

texts: I know that under FAR Part 135, specific approval is required for an RNAV SID/STAR (given via an OpSpec), but what about Part 91?  Does the aircraft/pilot have to be approved, and if so how is the approval obtained?


texts: Which is better a push fan, a pull fan or both

texts: intricate examination of modern by pass jet engines is despite where it is mounted, they use a pull fan configuration to generate thrust, which set up the most efficient, a pull fan or a combination of both on a single engine?


texts: How does a non US pilot buy a N reg plane?

texts: I wish to buy a single engine light aircraft. I have a FAA ppc. I wish to buy an N reg plane and use it outside the US. I believe I need to have a trust set up any info would be appreciated. I am not a US citizen


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

texts:
The NPR podcast A Surgeon Reflects On Death, Life And The 'Incredible Gift' Of Organ Transplant features Dr. Joshua Mezrich a surgeon who flies to other hospitals to retrieve organs for transplant discussing his book When Death Becomes Life.
In the beginning of the interview he says (my transcription effort):

There’s lots of different ways different centers do it. At our center we have some pilots who fly for the state who are on call for us, and typically we fly in a Pilatus, which is a single engine turboprop,
It is true that organs sometimes get sent on commercial planes; kidneys in particular, so if you ever see a cooler in between the pilots when you board it’s typically a kidney.

Are there little seat belts or other restraints for the organ-containing coolers kept in cockpits of commercial aircraft? Or are they just placed on the floor?


texts: Why does the turn coordinator ball move to the right during a climb?

texts: In a light aircraft like a C172 or PA-28, during a climb the ball in the turn coordinator moves to the right. Why?


texts: At what distance from magnetic north do pilots start referencing true north for heading?

texts:
The Earth's magnetic poles are constantly shifting, resulting in a significant distance between the true and magnetic poles. This means that while using them as references for heading at lower latitudes makes sense, using them as such while flying in polar regions causes often unacceptable inaccuracy.

In a simulator, I noticed that many modern airliners have a toggle to switch between referencing true and magnetic north as appropriate; but at what distance from a pole would this toggle be activated?


texts: Is a "breakover feature" required for airliner seats?

texts:
A "breakover feature" in airline seats is supposed to  assist in absorbing head impacts during a crash, when the passengers are in the brace position. However in some scenarios, most notably the forced water landing of  US Airways Flight 1549, the NTSB investigation found that the seats did not have this feature, which led to shoulder injuries in some of the passengers who were in the brace position.

My questions are:

Is it mandated by the FAA that seats in all commercial airliners
should have a breakover feature?
As a passenger, how do I know if the seats in my plane have this feature?
If the seats don't have such a feature, is it still wise to adopt the brace position in case of a crash or forced landing?


texts:
I know there are winds and other effects at very high altitudes but how high can storms with lightning and rain be?

Bottom line, let's say you are flying a craft with the ceiling of a U-2, can't you fly over any storm?


texts: How do commercial airlines prepare for pilots falling sick during the flight?

texts:
According to this article, the pilot suffered a heart attack mid-air and a passenger helped in landing the plane safely.

How does commercial airlines prepare themselves for these kind of situations. Do they specifically check if there are any pilots in the passenger manifest and inform the crew and pilots beforehand? Or, do they leave it to the co-pilot to take care of such situations? Or do they fly in a pilot (like mid-air refuel)?

On digging deeper I found that pilot sickness has caused several crashes:

Continental Flight 3407 co-pilot felt ill before crash near Buffalo, transcript shows
Plane damaged, pilot felt sick: fatal Transwest Air crash report
Report into fatal plane crash in NWT shows plane was damaged, pilot felt sick


texts: Does the flow in an afterburner have to be subsonic?

texts:
This question is prompted by the problem on page 350 of the fluid mechanics book by Landau and Lifshitz. The problem states, "A small amount of heat is supplied over a short segment of a tube in a perfect gas in steady flow in the tube. Determine the change in the gas velocity when it passes through the segment." This seems to me to be applicable to an afterburner. The solution is obtained by using conservation of mass flux and momentum flux and then increasing the energy flux by the heat added.  The change in velocity turns out to be given by,
\begin{equation}
dv=\frac{(\gamma-1)q}{\rho(c^{2}-v^{2})}
\end{equation}
where $\gamma$ is the ratio of specific heats, $q$ is heat added per unit cross-section per unit time, $\rho$ is density, $v$ is velocity and $c$ is the local speed of sound. This formula says that if the flow is supersonic $v>c$ then $dv<0$ and the gas velocity slows down. The addition of heat only increases the gas velocity if the flow is subsonic. So, my question is, "Does this result imply that the flow in an afterburner is subsonic?"


texts: Is the low air pressure on top of the wing the major contributor to lift?

texts:
I am kind of old time flyer. Started to fly with those primitive hang-glides with titanium frame and the yoke control, around 1966 and then after a few close calls and getting older I switched to small airplanes like Cessna 172 and Cherokee Warrior.

But from my decade of flying those hang-gliders I remember times when my wing fabric had collapsed because I must have been hit by a swift downdraft. I had to push it back up and hold it there a few seconds to stop stall. I needed to apply considerable upward force to push the fabric back up to airfoil shape. So I know how powerful the down-flow stream is.

If we consider the total pressure on top of the wing
 $ P_{wing} = P_{atm} - \frac{1}{2}\cdot\frac{dm}{dt}\cdot v_z^2$
and vertical speed $v_z = sin(\alpha)$, so by multiplying $v_z$ by the Wing surface we get the vertical down-flow and plugging it into the above equation we get a rough estimate of lift caused by low pressure on top.

I have checked many references on how lift is created and have not found any that refer to this major component of lift which I have personally experienced. Am I missing something?

I am adding a nice sketch of me rowing a boat. Using this setting as a poor man's wind-tunnel.
If you delay lifting your row at the end of its stroke it will glide back by the force of momentum of your boat. If you keep the row steady as shown on sketch and force it to drag behind you,what happens?
It creates a small swell, with water washing the outside face of the row a bit higher, shown on the sketch on red, and on the inside face of the row it creates a vortex at front and water washes the row a bit lower than lake level, shown in green.

My question is this: after reviewing many researches by labs and NASA and many other interested parties even prestigious universities, one finds less weight given to this significant part of the dynamics of lift: low pressure on top of the wing causing air to spill down to fill in by converting part of atmospheric pressure to kinetic energy, while relieving the wing top of full force of ambient atmospheric pressure?
I did a very rough estimate assuming the 176 square feet wing of Cessna  172 made of flat balsa and came up with approximately 850 lbs at 55 kn which is the rotation speed.

I am familiar with accepted theories like Newton's change of momentum of stream of air and NACA airfoils.


texts: What are the advantages/disadvantages of a forward-folding propeller?

texts:
The AMS Carat A is a motorglider with a forward folding propeller.

To my knowledge, this is the only production plane with this characteristic. The most popular self-launching gliders with front motors use props which fold back.

A naive guess is that aerodynamics come hugely into play here, although I don't have a notion if they're better or worse than a rearward folding prop.

What are the advantages to this folding style, beyond the fact that a rearward folding prop would simply not be practical on an engine-cowled nose?


texts: How to select a Lead In Fighter Trainer in the presence of both single engine and twin engine fighter jets?

texts:
A major part of fighter pilot training is learning the handling of the aircraft itself. On the other hand, automatic controls on modern fighter jets take away a lot of the pain and hassle. I am curious about the extent to which such ease of use plays a role in choosing the Lead In Fighter Trainer (LIFT) platform for an airforce.

Usually, it is assumed that the manufacturer supplying fighter jets will also supply the LIFT platform. But an airforce could buy jets from multiple vendors. It would be extremely cost ineffective to buy a different LIFT platform for each type of fighter jet. So airforces should try to standardize the LIFT platform they use.

Assume an airforce buys both single and twin engine fighter jets, from two different manufacturers. Neither aircraft has a twin seater version, so the first time pilots fly in them, they don't have an instructor sitting behind them giving instructions. Obviously, the aerodynamics and general handling of a twin engine fighter jet ought to be quite different from a single engine fighter jet. Now in making a decision on standardizing the LIFT platform, would this airforce take into account the presence of both single and twin engine fighter jets in its inventory? Would it procure two different LIFT platforms, one for training pilots towards single engine fighters, the other for training pilots towards twin engine fighters? Or does it make any practical sense for the airforce to choose only a single engine LIFT platform, or only a twin engine LIFT platform? What would be the pros and cons of such a decision?


texts: How much does it cost (on average) to run an airliner as a low cost airline on short distance flights?

texts:
Considering Germany is thinking about implementing new taxes to increase costs for commercial flights due to how cheap flights have become and the pollution they produce, I was thinking how much does running an airliner actually cost.

I've seen flights from Germany to Mallorca for less than 20 € and even if those are just a few seats and with next to no service, I was wondering, how much does a flight like that acutally cost. - Including fuel, all fees, the crew (average wages), maintainance cycles and if possible the aircraft purchase price itself.

For example, if an aircraft does 6 two hour flights a day and cost an initial 108 million € for an A320neo, assuming a 30 years lifetime and a resell value of maybe 30 million after that (is that realistic?) that would average the cost of the aircraft itself at roughly 7200 € per day or 1200 € per flight.

Regardless of airlines themselves, what are the ballpark values for all costs (fuel, crew, aircraft, fees, anything I didn't think about...) of an airliner per flight (for the sake of the argument assuming A320neo on short distance fligths, e.g. 2hrs)?


texts: What is a fuel over pressure protector on the A320 and other aircraft? What is the purpose of this hole?


texts: Can some planes turn using just the rudder or without banking?

texts: I know you use the rudder when banking to keep the plane in the correct orientation, but is it possible, when making a slight turn with say a small private cessna, could you just use the rudder to turn?


texts:
On a typical commercial trans-Atlantic flight, say from Frankfurt (EDDF) to New York Kennedy (KJFK), on a typical airliner (B777, A380, B787, etc.), when are Controller–Pilot Data Link Communications CPDLC established?

Is it generally before take-off, or just during the flight?
Is it only used during oceanic crossings, or for continental flights, too?
Will ATC instruct the pilot when to use CPDLC and when to revert back to voice communications?


texts:
I've been going over the new Master Minimum Equipment List (MMEL) for Textron Aviation Model 500 Series Citations and on page 36 a Ground Power Dispatch Switch is mentioned but I can't find any information or pictures of it online.

Can someone explain?


texts: Is it worth it taking flying lessons even though I can't commit to regular lessons right now?

texts: I can’t commit to flying on a regular basis right now. I’m close to a Class B airport with a flight school. There’s a C150 for 100/hr and a Zlin 242 for 160/hr. Instruction is 50/hr. There is, surprisingly, only one cheaper option nearby, and the price difference is small, so the closer option of the two is better. I’ve been studying the AFH, PHAK, and FAR/AIM, so I know my stuff. I’ve not yet taken ground school. I can’t commit to flying regularly right now. Is it still worth taking some lessons? I’d like to solo on my 16th birthday, so accruing hours is important. Should I wait until school is out and I can fly more regularly, or should I just go for it?


texts: Why are the 747-8 engines placed differently than on the older versions?

texts:
On the 747-200 the engines were tilted up to "meet the air at a streamline angle":

Source: Wikimedia Commons

Wikimedia Commons

Source: RcGroups.com

But in the 747-8, the engines are not tilted up:

Source: Airways News

Does anybody know why the engines are not tilted up anymore?
Thanks!


texts: Why is the ratio of TSFC at altitude vs. sea level different for hi-bypass vs. lo-bypass turbofan engines?

texts:
I've read up on how the thrust-specific fuel consumption of turbofan/turbine engines increases with altitude, and the Georgia Institute of Technology plot in particular seems to indicate that, for most modern airliners, the TSFC at cruise is 1.6 to 1.7 that of static thrust at sea level.

Now, I've come across this site (courtesy of the Wikipedia page for TSFC) and noted some wide variations with $TSFC_{cruise}$ vs. $TSFC_{0}$.

Some examples (data from the page linked above):

GE CF6-50C2: $\dfrac{TSFC_{cruise}}{TSFC_{0}} = \dfrac{0.630}{0.371} = 1.698$.
P&W PW2040: $\dfrac{0.582}{0.330} = 1.764$.
RR RB.211-535E4-37: $\dfrac{0.598}{0.324} = 1.846$.
P&W JT8D-15A: $\dfrac{0.810}{0.590} = 1.373$.
RR Conway RCo.12 Mk.508: $\dfrac{0.822}{0.726} = 1.132$.
RR Spey RSp.4 Mk.511-5: $\dfrac{0.770}{0.600} = 1.283$.

The upper three examples are high-bypass turbofans, and the lower three are low-bypass.  Notice the big differences in the TSFC ratios.

What causes this difference?


texts: How common are go-arounds at Penghu Airport?

texts:
A friend mentioned being a passenger during a commercial aircraft landing at Taiwan's Penghu Airport (MZG, RCQC) where they had almost touched down but had to abort and keep going due to sudden wind event causing "scary motion". They circled back around and landed minutes later uneventfully.
I'm sure there are standard aviation terms for these but I don't know them.
I mentioned that these happen somewhat regularly especially at certain airports and that one of the first thing student pilots learn is how to do touch-and-go's.
Now I'm curious if there are rough numbers for how often this happens per year and if airports like Penghu's see these more frequently? Something like one out of every 100 days an aircraft has to come around and try again at that airport, or one landing out of 10,000 or similar type of summary statistic.


texts: Which compressor is more like to surge and stall - axial or centrifugal?

texts: I am studying about stall and surge in rotodynamic compressors and want to understand which one is more prone to these phenomena.


texts: What is the difference between static and dynamic stall?

texts: What are the static and dynamic stalls on the aircrafts wing? When would we encounter static and when dynamic one? What is the difference between them?


texts: Why is there a maximum landing weight limit?

texts:
I was told that if the aircraft's weight exceeds the maximum landing weight, it could cause a structural damage during landing, but why?

My understanding is that with a heavier aircraft, I need fly with a faster approach speed; but if the runway is long enough, I could land with more lateral energy with minimized vertical energy without causing any structure damage, is that right?


texts: How can pilots fly VFR over-the-top in overcast conditions?

texts: It's apparently legal for pilots to fly over the top of clouds and fly VFR. However, I don't understand how it's possible to do so, especially since there is no visual reference to rely on to ensure that you are heading in the right direction. So, how exactly does this work, are there any limitations on this and is it possible to be done safely?


texts: What kind of ADS-B identification code is FFxxxx, where xxxx are numbers i.e. FF0024?

texts:
I live near an airbase and use an ADS-B receiver that picks up aircraft using regular ICAO assignments. They do not include flight path details or position info, but can be identified by the ICAO number which is a civilian aircraft identifier. Sometimes, it captures aircraft SSR returns with what appear to be invalid numbers, beginning with FF followed by 4 digits, such as FF0024 FF7777.

Are these drones? cruise missiles? Aurora? Or some other military aircraft identity?


texts: How does a single engine tail wheel landing gear airplane turn when it is on the ground?

texts: Say Cessna 140 as in this video, look like no additional device to make it turnable when it on the ground. It is a single engine and a tail wheel landing gear. Then, how does it turn?


texts: Why not stream outside cameras into the in flight entertainment system

texts: Why do some carriers choose not to stream external views on planes where GMCS cameras are standard, such as the 777-300 or the Airbus A380?


texts: What runway is used in a 90 degree crosswind?

texts: If an airport has runway 09/27 and the wind is at 180 or 360, which runway is used? Is it possible for both ends to be used depending on the amount of traffic?


texts: Is Vy closer to Vbg with a variable pitch prop

texts: My experience with fixed pitch props is that Vy is generally higher than Vbg due to engine efficiency issues. If I set my prop pitch so optimal engine rpm is at Vbg, will Vy = Vbg?


texts: What is the difference between SoCal Approach, SoCal Departure and SoCal TRACON?

texts: I've heard these 3 terms in ATC recordings and on web pages. Do they all use the same frequencies and the same controllers?


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

texts:
In the Southwest corner of LAX (at the intersection of Imperial Highway and Pershing Dr.) there is a strange looking area that appears to have some abandoned airplane parts. Also, it looks like a road-striper had a good time one day doing donuts around one of the artifacts. Anyone familiar with this area and what it is used for?

See Google Maps


texts: Airbus Beluga, what is aft of the cockpit?

texts:
In the Airbus Beluga (and Beluga XL), the main cargo deck runs the full length of the aircraft, starting just above the cockpit. Is there more usable space behind the cockpit? Or are there fuel tanks here?

In the attached image of a Beluga, there appears to be large door immediatly forwards of the tailnumber, and a smaller door aft.

Image taken from Airbus Beluga promo site


texts: What happened with the YF-16 prototypes?

texts: What happened with the original two prototypes of the YF-16 that were ordered during the Lightweight Fighter Program? Were they converted into combat-capable F-16's?


texts: Why is dropping off passengers on the ramp by bus not more common?

texts:
Even at remote terminals as discussed in this answer it seems there's a preference for using a jet bridge to get passengers to and from the aircraft.

Can't the passengers just be bussed directly to the aircraft rather than the remote terminals?
Why the use of a jet bridge here if they can use stairs at other times?


texts: Why do intermeshing helicopters use asymmetric airfoils?

texts:
I am referring to the Kaman K-max and the Kaman Huskie here. They both use NACA 23012, which is an asymmetric airfoil. Any reason as to why this is? Is there a different mechanic in play when intermeshing rotors are considered? Does Reynold's number change due to factors that don't affect normal helicopters?

Edit - I can see how my question can become very broad. My question would be answered if somebody could explain what factors come into play in intermeshing rotors that affect the choice of airfoil.


texts: What prevents a passenger from opening the emergency door on his own will, mid-flight?

texts:
I have never sat on the emergency seats near the wings, with the emergency exit. I have seen cabin crew instruct the passengers seated near the door on how to operate the door.

My question, what prevents a 'rogue' passenger from opening them mid-flight?


texts: What is the speed above which painting an aircraft black (or dark) results in lower skin temperature?

texts:
The Concorde is painted white for thermal reasons. If I understand correctly, it is done to reflect as much radiation as possible in order to lower tempereture. But when the skin is really hot (SR-71, reentry vehicle such as the Space shuttle,...), it is better to have a black/dark skin so that it radiate internal heat.

In short: when flying supersonic the aircraft should be painted white to reflect incoming radiation, and when flying hypersonic the aircraft should be painted black to radiate internal heat.

My question is: what is the speed threshold below which painting white results in lower temperature and above which painting black results in lower temperature?


texts: Does static longitudinal stability require download on the tail?

texts: After having encountered this meme too often for comfort, I ask myself today in order to have the possibility to explain the issue in detail.


texts: How should a glider pilot signal turns to the towplane?

texts:
When in aerotow in a glider, I thought the correct way to get the towplane to turn right (say) was to move gently to the left. That would gently nudge the towplane’s tail to the left, which would then point the nose to the right and be a good signal that the glider pilot wants to turn right.

The FAA glider flying handbook displays the opposite technique in a diagram:

I don’t understand this. If you move right to ask the towplane to turn right, doesn’t that put the glider on the inside of the turn, and put you in the wrong place to follow the towplane around?

Which is the correct direction?


texts: For the recertification flight(s) of the 737Max, will the FAA want to see a live runaway stabilizer?

texts: With Boeing ready to start the testing Monday, will the FAA want to see a simulated runaway trim failure in flight?


texts: Combating flutter with mass distribution?

texts:
Considering aeroelastic flutter, when an eigenfrequency of the wing meets with an aerodynamic frequency, the commonly mentioned solutions make sense: avoid the convergence zone by limiting speed, or by increasing the wing's eigenfrequency trough stiffness, reduced weight, or reduced span.
Makes sense, especially if I use the spring and mass model for the wing:

I'll use the analogy with the conventional spring as it makes things easier to understand for me.
So Wikipedia says: "Prediction involves making a mathematical model of the aircraft as a series of masses connected by springs and dampers which are tuned to represent the dynamic characteristics of the aircraft structure. [...] Small carefully chosen changes to mass distribution and local structural stiffness can be very effective in solving aeroelastic problems."
My 3 questions are:
1: Do I understand correctly that with this approach, the wing will act similarly to the following model, where the motion is rather chaotic?

2: This should have no certain frequency. Does this mean flutter is avoided?
3: Does this mean flutter can be avoided by redistributing mass around the wing, without increasing stiffness or reducing mass?


texts: What is the purpose of having a robotic arm fly a Boeing 737?

texts: What is the aim of using a robotic arm instead of embedding the system on a plane? I read the 'Robotic Co-Pilot Autonomously Flies and Lands a Simulated Boeing 737' documentation but it didn't help me to understand.


texts: Should I put yesterday's date for destination date/time on a flight plan if the flight is to go east bound across Zulu +-12 time zone?

texts: The international date line runs across the middle of Pacific Ocean opposite (12 hour ahead or before Greenwich mean time (zulu)) Zulu time.  It is the boundary where 24 hours elapses and the date changes.  I am trying to clear the fog in my mind how pilots account for the date on their flight plan when the flights cross Zulu+-12.


texts: What prevents BFS from becoming unstable when pitching from horizontal to vertical?

texts:
In this video from (SpaceX's BFS landing) there is a point where the ship tilts from horizontal « belly first » terminal velocity freefall, to vertical « engine first » landing position.

The graph on the right shows that this leads to a vertical acceleration roughly from mach 0.26 to mach 0.31
induced by drag reduction due to tilting manoever itself.

Gimbaled engines are only fired when the ship is vertical, which could mean this whole tilting manoever is meant to be aerodynamically achieved.

Actuated fins and canard fins are designed to increase or decrease drag about center of gravity of the ship, like a skydiver does by moving its limbs.

But as soon as the ship starts tilting from horizontal to vertical, its body and actuated fins will generate lift. (instead of only drag)

The ship will start gliding backwards. Lift will increase to a maximum point when fins aren't stalled anymore.

Question is :

At this point (gliding backwards, almost vertical, mach 0.3, short before suicide burn) the whole ship should become unstable if center of lift is between center of gravity and aft part of the ship (engines) It's a bit like imagining one backward flying VariEze, or the aerobatic figure called "tailslide"  : It will flip over, the same way a  badminton shuttlecock does when it changes direction.

When lift becomes significant, what prevents the ship from naturally tilting back to horizontal or abruptly yaw or roll to some unpreditable new attitude (shuttlecock like)?

I agree if cg is very far back, inward folded aft fins and canard fins could create the correct pitching moment for the BFS to tilt vertical. But where should the cg be for it not to tilt about yaw axis, (or induced roll due to the massive fixed vertical fin) Some airliner trading a vertical stabilizer on its tail for one above its cockpit wont be very stable about yaw axis either.

Note that when looking at animations provided by spaceX, aft fins seem to have only one degree of freedom : The huge hinges allow changes in dihedral.

Canard fins seem to act the same but may have one more (invisible in animation) degree of freedom: variable incidence, which could add control to pitch and roll, but still is useless for yaw control.

Edit: please focus on yaw axis, consider seconds 1105 to 1107 in animation.
Canard fins don't play any role in stabilizing yaw. How can the aircraft not tumble because of yaw instability and induced roll?


texts: How is flow separation related to the chord length of an airfoil?

texts:
I came across this question while studying stalling of airfoils. How does the chord length of an airfoil affect the position of the separation point of flow?

https://en.wikipedia.org/wiki/Flow_separation

The Wikipedia article on flow separation isn't very clear on what is the relation between location of separation point and Reynolds Number (and thus Chord Length).


texts: What happens when changing the throttle on a PT-6 engine?

texts:
Imagine a PT-6 in cruise flight. What would pushing the throttle forward for increased power show on the engine instruments? We know (I assume!) the prop RPM remains constant by varying the pitch, but what goes higher? Torque or TIT?

And what does the pilot do in descent for landing? Does pulling the throttle back for a long descent decrease the fuel flow to a point where it may not sustain combustion and cause flame out?


texts: Why are there speed restrictions applied after deicing an aircraft?

texts:
The information about the 737 here mentions an interesting limitation:

  737-6/900 without stiffened elevator tabs:

  After any ground deicing/anti-icing of the horizontal stabilizer using Type II or Type IV fluids, airspeed must be limited to 270 KIAS until the crew has been informed that applicable maintenance procedures have been accomplished that would allow exceedance of 270 KIAS. Once the applicable maintenance procedures have been accomplished, exceeding 270 KIAS is permissible only until the next application of Type II or Type IV deicing/anti-icing fluids.

How are certain deicing fluids, un-stiffened elevator tabs, and airspeed related here?


texts: I would like to insure my foreign registered aircraft in the USA

texts:
I am looking to fly my UK registered aircraft in the USA this summer.  At present UK insurance companies will not insure aircraft flown in the USA and US insurance companies will not insure foreign aircraft.  I see 2 possible solutions:

Find a US company that will insure a foreign plane
Temporarily register my plane in the USA.

Does anybody know if either of these is possible?

Thanks


texts: Would a takeoff be aborted if 'rotate' is not called out?

texts: As captain of a Boeing 747 on a take-off roll I am expecting my co-pilot to call out V1, Rotate, but he does not call out rotate. Do I abort the take-off?


texts: Which portion of combustion energy is used to spin the compressor of a pure jet engine?

texts:
In level flight at constant speed, it is correct to assume that the quantity of energy created by fuel combustion (FE) is exactly extracted by the turbine section (ME) and is used solely to spin the compressor section?

In other words, the propulsive energy (E4) is equal to energy in air the aircraft encounters (E1).

If this assumption is incorrect, what is the correct relationship between energy quantities E1 to E4? Maybe two extremes could be used for illustration: No thrust (idle) and full thrust.


texts: Is it possible for someone to buy a fighter jet?

texts:
Yesterday I came across a video of a person who purchased 3 Harriers ("Harrier Jump Jet").

This brought up the question of: assuming he/she has the capability of paying for the price, is it possible for a regular civilian to purchase a fighter jet?

The video did note that the person was a retired test pilot. Is that a reason why he was able to purchase the jet?


texts: How does change in airspeed affect pitching moment?

texts:
In aircraft with conventional elevator control, if I increase the speed, the horizontal tail sees higher velocity and hence higher lift. Does it mean that increasing airspeed creates nose down pitching moment (i.e. decrease in AoA) and vice versa ?

If So, it means if i want to increase the speed keeping altitude constant, the aircraft automatically gets trimmed at new trim AoA or i manually have to change the AoA using elevator?


texts: Why are the largest civilian aircraft not adapted for military use?

texts:
Frequently, civilian aircraft models are militarized, e.g. into the role of tankers, AWACS and others.
In this militarization, we see a lot of "medium-large" aircraft, such as B707, A330.
The super-large models, B747 and A380, however, do not see militarization. The current 747-based Air Force One, comes to mind, but that's more or less a one-off.

What are the reasons for not seeing more B747s and A380s being put into a military role?

A huge B747 or A380 would make a quite extensive flying gas-station.


texts: What is the physical definition of turbulence?

texts:
To aviators, the definition of turbulence by measuring the results is widely known: example. But if we were to generate a turbulence forecast as a meteorologist, there need to be some kind of physical parameters that constitute the different levels of turbulence.

Maybe something like "wind vertical velocity" or "vorticity" etc. ...

What are these parameters and what different levels are defined?


texts:
The question Are pilots allowed to let passengers fly the plane? is interesting to read, noting that pilots are permitted to allow passengers to fly.

I recall an Air Crash Investigation episode (AFL593) where the pilot pretended to allow his son to manipulate the controls of an airliner, without realising the autopilot had been disconnected, resulting in an accident.

I'm wondering how commonplace this is? Is this an isolated incident?

On the flip-side, I've heard of at least 3 occasions where passengers have successfully landed planes, e.g:


texts:
One of my co-workers is a FLAT Earth believer. I have tried all kinds of logic and facts to disprove his belief.  He is not the sharpest knife in the drawer so trying to explain Gravity, atmosphere moving with Earth, etc is difficult.  I have read the threads trying to explain if pilots make adjustments for curvature. Answers/explanations are all over the place...

What I need is a very uncomplicated explanation as to how a plane tracks along with the curvature of the Earth WITHOUT pilot making adjustments.


texts: The "area rule" states that the supersonic drag on an aircraft is related to the total area on part of the aircraft. What is the exact definition of the rule? Why does this happen?


texts:
I am working on a pet project to write a game with flight physics. It will not be a simulator but instead much simpler.

What I have done so far

I have created winged components that generate lift and drag using the basic formulas I found online. I apologize if some of the debug info is not standard terminology.

The green arrows in the image show the force and magnitude begin applied. The yellow lines are the relative airflow.

What I cannot get working and understand

At first all the components used the same forward speed calculated by looking at the CG. Just an easy way to see what speed the plane was moving. The plane flew straight when "thrown" level and if will self correct if thrown with a slight roll angle.

The problem starts when each component starts calculating its individual forward speed. Even with dihedral applied to wings the plane will start rolling to the left more and more.

You can see that the left wing has a slightly higher AOA as the result of the dihedral. BUT it has a lower velocity than the right wing because the plane is yawing (I think). This lower velocity causes the right wing to produce more lift and the plane rolls more to the left. The more it rolls left the more the right wing speeds up causing it to produce even more lift.

I have tired to increase the rudder, but that didnt help at all. Removing the rudder causes the plane to over correct, and then to roll to the left too.

Can any body explain what is suppose to happen when a plane rolls.
From what I see the plane rolls left, it pitches slightly down. The right wing "swings" forward faster than the left causing more lift.....


texts: How do I fly to Borrego Valley (L08) if it's inside a CA state park?

texts: I'd like to fly to Borrego Valley Airport (L08) and it's inside California's Anza-Borrego Desert State Park.  How does this work, given that I'm supposed to say at least 2000 feet AGL when flying over a state park?  Am I allowed to descend below 2000 feet AGL only for takeoff and landing at the airport, or can I be below 2000 feet AGL at other times when flying over the state park?


texts: What is the difference between "closed traffic" vs "stay in the pattern" request?

texts: My instructor made "request right closed traffic..." call before practicing a series of landings. Just wondering, what is the difference between this request and a "stay in the pattern..." request? Which one should I use when?


texts: How much thrust is produced on an A320 at takeoff and during cruise?

texts: Where can you get the drag polar of the A320 at cruise and TakeOff?


texts: Where exactly are the pitot tubes positioned on the A330/340?

texts:
While going through a document for analysis I came across a statement saying the positions 1 and 2 of the pitot probes are symmetrical on long-range Airbus aircraft but not on their single-aisle aircraft.

Can any one please confirm it by giving suitable reference? I didn't find any clue on the internet.


texts: Why can't you ditch your aircraft in the sea?

texts:
Disclosure: I'm just a random guy who knows nothing about aviation. :-)

I read:

  A voice in my earphones was shouting: “Ditch the plane! Ditch it in the ocean!”
      It must have come from the tanker skipper or one of the destroyer commanders down below, because every jet pilot knows you can’t ditch a jet and survive. The plane would hit the water at a very high a speed, flip over and sink like a stone and they usually explode on impact.

Okay, but the physics-y side of me wonders why you can't do the following:

Get ready to jump out (open windows, remove all attachments, etc.)
Glide down as close to the surface of the ocean as possible, maintaining some momentum
When you're as low as possible (but still high enough to allow this maneuver), suddenly pull up the nose as high as you can while keeping altitude constant as long as possible

I expect that, if done properly, this could nearly halt horizontal motion of the aircraft; when the momentum is finally lost, I expect the plane would suddenly "drop" in the water from a few feet above, after which you can (hopefully?) jump out of the cockpit immediately.

Now I'm not expecting a 100% survival rate here (I'd almost certainly die trying this), but it certainly seems to potentially beat jumping out of your plane at 15,000 feet and risk getting chopped up by the tail or having your parachute not open (and consequently breaking your spine, etc.).

Where am I going wrong with this? Why is ditching your aircraft in the ocean not an option?
(Does it e.g. depend on the type of the plane?)


texts: What do these ramp markings mean at KIFP?

texts: As a pilot, what do I need to know about these ramp markings at KIFP? Are they operationally significant?


texts:
Would a biplane be able to fly if the upper and lower wings were in opposite dihedral? Imagine a wing configuration similar to the fictional "X-wing" design from StarWars. What would be the theoretical pros and cons of using such an approach? Ignore the engines, fuselage, tail, etc

What happens if you take it to its logical extreme and make all wings at 45 degree angles?


texts: Can aircraft other than rockets go to space?

texts:
I always wondered if it was possible for planes and other aircraft to leave the Earth's atmosphere. Normal commercial transport airplanes can fly pretty high, but then they need air to get the speed boost from. Reactive engines seem like a better idea, but I don't know how much importance air has for them.

Is it possible to get to space from Earth's surface using a non-rocket aircraft?


texts: Where can I find drawings or diagrams of the Boeing 737-800's internal layout?

texts:
I am working on an alternative fuel system for my final school research. I am applying it to the 737-800. Now I could not find info on how the internals are situated. Of course pictures of the cabin are widely available. However I am looking for drawings, pictures or graphs on the cargo compartment, systems placement like gear, hydraulics, pumps or whatever. Basically the whole internal volume and what it is occupied by.

This is maybe a bit demanding but any info is really helpful.


texts: Is a Compass Swing Platform part of a runway or taxiway?

texts: I am trying to work out if the compass swing platform is part of the runway or taxiway.


texts: At what point does an aircraft become an airliner?

texts:
For me, the term 'airliner' conjures up an image of a passenger jet that is capable of hosting a large number of passengers¹ but I'm finding it difficult to source a reputable definition or etymology despite the term has been sourced int the early 20th century.

Since the term has been in use since 1908, jet as in jet airliner may be inferred by the modern user but it obviously wasn't part of the original definition.

The word itself would seem to indicate that airliner refers to an aircraft used by an airline (a company that provides air travel for the public), but would that extend to bush pilots with small prop-driven Cessnas or passenger helicopters?

  airliner - A large passenger aircraft. A large plane for carrying passengers:
  a commercial/commuter airliner   source: Cambridge English Dictionary

  airliner - An airplane operated by an airline   source: Merriam-Webster Dictionary

  Is this an 'airliner'? How many passenger seats need to be added before it becomes one?  (image courtesy of The Bush Pilot Company)

The term seems so vague that even the airliner tag on this site only uses 'large' to define size or capacity.

Some reference work definitions include cargo aircraft but the predominant emphasis seems to be on passenger aircraft with no upper or lower limit criteria.

I suppose that this term could be relative to the observer or situation but if the term 'airliner' was used in FAA regulations then I'm sure there must be an appendix somewhere that provides a definition. My research has come up empty.

Apologies if this is a dumb question and the term is intentionally meant be vague with only 'large aircraft' or 'many passenger' as criteria. Given proper references as support, that could be an answer.

¹ This previous question got me wondering exactly what was the criteria before any aircraft could be called an 'airliner'.


texts: What's this biplane built by a 16-year old?

texts: I was told that this plane was built by a 16-year old in the 90s. Ever since, I've been bent on finding the specifications, name, etc., of this airplane with no success.


texts: Why does an airliner fuselage have a constant section over its length rather than a tear drop shape?

texts:
It is usually stated than a tear drop shape is a good shape for aerodynamic efficiency:

Adapted from Nasa

On the other hand, fuselage on an airliner has most of the time a long cylindrical section with round/tapered ends. I understand an aircraft has other constraints than just having the lowest possible drag. It comes to mind a cylindrical shape allows the same number of seats in most of the rows and also prevents to increase the section of the forward cabin.

Without further explanation, it seems curious the fuselage has not a shape between a rounded cylinder and a tear drop shape which is often seen for gliders:

Source

Without going into deep details, what are the most important reasons preventing such design?


texts: Why Heading Indicator is not magnetic itself and need magnetic compass?

texts:
I read this while I was preparing for my knowledge test:

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

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

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


texts: Is there a crosswind that would perfectly cancel out the "torque" of a C172 on takeoff?

texts: We all know that on takeoff you need right rudder in order to balance out the "torque" of the propwash hitting the tail.  Is there an exact crosswind that would cancel out this torque?


texts: When, exactly, were the DC-8’s airbrakes removed?

texts:
The DC-8 was originally equipped with airbrakes on the lower rear fuselage, but these were quickly removed.  Wikipedia says that they were removed before the DC-8 entered service:

[...]  Douglas made a massive effort to close the gap with Boeing, using no fewer than ten aircraft for flight testing to achieve FAA certification for the first of the many DC-8 variants in August 1959.  Much needed to be done: the original air brakes on the lower rear fuselage were found ineffective and were deleted as engine thrust reversers had become available...

Emphasis added.
However, according to the CAB report on the crash of United Airlines Flight 859, the first few DC-8-10s, at least, did have airbrakes when they entered service, and at least one was using them as late as July 1961:

When this action failed to straighten the landing roll he knew the aircraft was going to leave the runway.  He said he used the emergency airbrakes to slow the airplane as much as possible before leaving the runway.  [...]
[...]  The second officer said that after touchdown a series of events occurred which he could not place in sequence with any degree of certainty.  He saw ejector indicator lights blinking, heard a foot thumper, saw the captain reach for the emergency airbrake handle, and saw that the aircraft was heading about 30 degrees off the runway.  [...]  [page 4 of the report]

Emphasis added.
And it’s definitely not misusing the term “airbrakes” to refer to the aircraft’s wing spoilers, since it refers to those as “spoilers” elsewhere in the report.
When were the DC-8’s fuselage airbrakes removed?


texts: What are these things on the A350's instrument panel?

texts:
https://imgur.com/a/BF2Ghpv
.
.
On the FCU Panel, there are some buttons or switches that are not on a320s and some older Airbuses except the A380. what's that and what the function?


texts:
In a recent news article on an Airbus A400M crash, it has the following line:

  Sources have told Aviation Week that aircraft MSN23, destined for Turkey, featured new software that would trim the fuel tanks, allowing the aircraft to fly certain military maneuvers.

I understand what trimming is, but what does it mean to trim the fuel tanks?


texts: Which small, light aircraft are suitable for operating at very high elevations?

texts:
I live in Jammu and Kashmir, in an area with an average elevation of 4,500m / 14,700ft MSL . I would like to know what would be a good and cheap light aircraft to carry 3-4 people for a 3-4 hour flight in that location for heights upto 23000ft as mountains are at least this high?
Runway length is 3700ft and asphalt.
Budget is aroung $1 million to 1.5 preowned


texts: Could an electric engine provide the same performance as jet engines on current aircraft?

texts:
I have looked at various questions on this SE site regarding this topic but I have not really found a satisfactory answer. Some comments here regarding torque and power in electric motors vs gasoline engines were helpful. Additional info also found here.

Underlying my question is the assumption that battery technology will considerably advance from what is available commercially now. Simply assume that providing the electric motor with enough power is not an issue and that the weight of the battery is equal to fuel.

Is it possible to build an electric aircraft engine that would allow current commercial airplanes the same capabilities as jet engines available today do?


texts:
I was doing a question about a fully hydraulic elevator and it's position in relation to the trimmable horizontal stabiliser and the explanation of the answer contained the word "redatum". What does it mean?
Full question, answer and explanation:

Q: What is the position of the elevator in relation to the trimmable horizontal stabiliser of an aeroplane with fully hydraulically operated flight controls that is in trim?
A: Elevator deflection is zero
A fully hydraulically operated flight controls is an irreversible system, and the trim is a redatum, as there is no physical connection between the stick and control. Therefore there will be no elevator deflection when trimmed.


texts:
After reading this question about being cleared to go faster than 250kts in airspace that otherwise has a speed limit, I began to wonder how far can Air Traffic Controllers (ATCs) can bend the rules on an aircraft-to-aircraft basis?

Is there a limit to what exceptions ATC can make for someone?  I'm particularly interested for the answer in the USA, but I'm sure information about other countries would also be enlightening.


texts: Does the parking brake provide additional deceleration in an abnormal situation?

texts:
During a rejected takeoff at a speed > V1, you obviously try to stop with all available means since a runway overrun is a very undesirable result. In this case, could using the parking brake in addition to the normal brakes and reverse thrust help slow down the aircraft faster?

I know that the parking brake can be used to slow down the aircraft, e.g. in the “no breaks available” memory item on an A320 but does it help when the normal brakes are available?


texts: Why would an artificial horizon's roll axis be different on ground and in flight?

texts:
Sorry, if I'm a bit verbose here, but since I don't understand the problem, I have difficulties to describe it.
I created an artificial horizon using an Adafruit precision 9 DoF sensors and their AHRS SW pack, which is quite sophisticated using Kalman Filters and Covariance matrices for fusion. On my dev table, everything works fine. Roll, pitch, yaw, tilt compensated heading, even if I shake it. I clipped it onto my shaver to simulate vibration, everything OK! Hence, I believe its not a HW or SW problem.
The problem occurs when I mount the device onto my ultra light aircraft. Pitch and Yaw/compass course remain OK, but roll becomes strange. When I turn, the roll axis moves into the right direction, but not enough (say 30° instead of 45) and even if I keep turning at the same bank angle, the roll axis displayed moves back to horizontal. As I said, when I turn the sensor from 0° to 45° on the ground, it rolls from 0 to 45 and stays there!
So the only difference is, IMHO the fact that on my dev table, things are pretty stable, while in the air, the sensor moves at 180 Km/h and in curves there might be some issues from centrifugal forces, which dilute the accelerator values and the Kalman filter tries to correct the Gyro rate by an exorbitated accelerometer value, which are normalized, showing 0.99g when flat on the table.
Any suggestion ?


texts: Why is the MD-88's front starboard door smaller than its port one?

texts:
Having been on a few airplanes of the MD-80 family, I noticed that the front starboard doors of the planes were smaller than the ones on the port side. Why may this be the case?

This may also be the case with the rest of the DC-9 and B717 family as well, but I don't remember that clearly anymore about those other planes.


texts: When airplane pilots begin a 10 minute wait timer when lightning strikes, is there a geometric reason behind it?

texts:
Preface
This question is taken from a similar one inside the mathematics stack exchange.  I followed the suggestion given in the comment by Jyrki Lahtonen and posted said question here.
Background
Recently, on a flight back from Charlottesville, NC to Logan Airport, MA, the Pilot stated this to his passengers over the intercom, I paraphrase:
As you can see out the window, we just saw some lightning strike within 3 miles of our plane. Because of this, they closed the ramp gates. Every time lightning strikes within three miles of our plane, we have to reset the wait timer to ten minutes.
This made me wonder if there was a mathematical connection between the distance of a lightning strike and the amount of time needed to wait for take-off to ensure another strike will not occur on the ramp.
Work
Let the "area that causes a delay" when lightning strikes be represented by a circle of radius 3 miles. In addition, let us envision a scenario where lightning strikes on the circumference of the circle, i.e. 3 miles away from the plane, which is the farthest distance from the place that will trigger a 10 minute wait.
The intersection of these circles is a clean venn-diagram shape, and results in an area of (9π)/3 sq.mi. or 3π sq. mi., which is about 9.42 sq. mi, and the ceiling of which would be 10.
Question
Given that the pilot stated that a wait time of 10 min would be triggered if lightning struck within 3 miles of the plane, and the area in between a strike on the circumference of 3 miles and the plane results in a ceiling of 10, is there any mathematical basis for a lightning strike wait time of 10 if given a "danger zone" of 3 miles?


texts: What is the relationship between "automatic flight control system AFCS", "autopilot", "flight director" and "flight management system FMS"?

texts:
I'm studying aircraft maintenance. I looked in my books and searched the web but couldn't make a big picture of the concept of autopilot.

Specifically what is its relation to modern systems like FMS.
Is the AFCS an independent system or does it take orders from the FMS?
What are AFCS subsystems?
Is the flight director the old version of FMS?


texts: Is pressure pattern navigation used in the real world? How effective is it really?

texts:
Pressure Pattern Navigation is a method of capturing favorable tailwinds when flying long-distance trips.

The basic methodology can be found in this PDF.

I imagine that airline captains aren't all that free to choose their routes (correct me in the comments if I'm wrong!), but this seems to be perfectly suited for the corporate and charter crews among us. However, I've never heard of any crews using it in real life.

Does pressure pattern navigation work in the real world? How effective is it?


texts: How do partial- and full flaps compare for gusty approaches?

texts: From an aerodynamic aspect, how do partial flaps and full flaps compare for gusty approaches?


texts: Which aircraft manufacturers still include Vertical Situation Displays (VSD) feature in their cockpits?

texts: I'm curious about the aircraft manufacturer names who still interested in including the VSD on lower part of Nav Display (I read about Boeing 737 only). Are there any other guys on this filed still? I know this would be useful during the landing and takeoff.


texts: Why does the Ka-50 (Hokum) have two main rotors, one on top of another?

texts: Why does the Kamov Ka-50 have two main rotors, and is this a better design than a conventional one rotor?


texts: What is the name for yaw, pitch and roll together?

texts:
What is the name for yaw pitch and roll all together ?

I've heard CMD used to refer to all of that information but don't know what it stands for.

Is CMD correct? if so what does it stand for? is there some other word?


texts: Why is parking brake set OFF before jacking?

texts:
I have a question about the procedure to jack the aircraft for wheel replacement. According to the manual, it required to set the Parking brake OFF before starting jacking at the Main Landing Gear.

I curiously wonder if the brake is set OFF to let the wheels on the other landing gear could rotate freely on its axle.

Why don't we keep the parking brake ON to prevent the aircraft moving and slip out of the jack?


texts: Why would FlightAware show this meandering flight path?

texts:
Today's BA219 from LHR to DEN (2018-03-20) appeared to fly 5 zigzags just before and over the Hudson Bay in Canada at around 18:15z. Prior to that, its flight path matched its planned route very closely.

I know that congestion avoidance can sometimes lead to flights being asked to fly doglegs (as in Why did this plane fly in a zigzag pattern?), but this flight was still 3 hours from its destination and still exceeding planned speed when it appeared to fly zigzags. I don't see any weather issues on radar at the time.

After the zigzags seen in the FlightAware capture, the flight track straightened up and flew parallel to its planned route. This appears to be a track data problem, not the actual plane's path.

But on FR24 that path is not there:

I've seen 'Why do aircraft on Flight Radar 24 jump around randomly sometimes?', since they are different services, what could be the reasons for FlightAware to behave like this? Also note the linked FR24 post is a different more jagged path than the one here.

FlightAware tracks from other flights show similar zigzags in the Hudson Bay area. Presumably this is just noisy tracking data. Any idea why that happens in this particular location?


texts: Does oxygen become less available during night-time?

texts:
The following excerpt is from the FAA's Pilot's Handbook of Aeronautical Knowledge (page 7-37):

  Some people flying above 10,000 feet during the day may experience
  disorientation due to the lack of adequate oxygen. At night,
  especially when fatigued, these effects may occur as low as 5,000
  feet. Therefore, for optimum protection, pilots are encouraged to use
  supplemental oxygen above 10,000 feet cabin altitude during the day
  and above 5,000 feet at night.

The book, in vague terms, suggests that the amount of oxygen (i.e. oxygen molecules) available at a certain altitude at night is less than in daytime.

The regulations do not differentiate between day and night in regards to supplemental oxygen.

What would be the scientific reasoning behind this?


texts: Is possible to stick two '2-blade' propellers to get multi-blade propeller?

texts:
Does propeller blades' airflow interfere with each other blades and decrease overall thrust? Should I consider high pitch propeller for this purpose?
My purpose: I'm looking for a 20-inch four-blade propeller for a tail-sitter Drone. But commercially I don't find anything like that. So started looking at making a  4-blade/6-blade propeller with 2-blade propellers. Thrust density is my first priority compared to efficiency.


texts: How do a narrow airframe and canards keep supersonic shock waves from coalescing?

texts:
In a follow up to my previous question:  How does the X-59 acheive quiet supersonic flight?

Canards and a long narrow airframe were cited as design choices to prevent shock waves from coalescing. How does this design shape achieve this goal? How does this shape affect the flow field such that the shockwaves do not coalesce?  I want to understand this in terms of the physics and aerodynamics of the shockwaves. It would be useful to see a side-by-side comparison to other supersonic aircraft like the Concorde.


texts: What is the best extinguishing agent when wheels catch on fire?

texts: What extinguishing agent must be used in the event of a fire involving wheels/tires? Why?


texts: Can anti-radiation missiles be used to target stealth fighter aircraft?

texts:
What I understand is that anti-radiation missiles are accurate and long range.
So, assume that a fighter aircraft is 100% invisible on radar. However, its radar is transmitting energy continuously which can be detected and targeted using anti-radiation missiles. As Wikipedia suggests there is Russian air-to-air anti radiation missile (Vympel R-27EP).
Wouldn't such a missile neutralize the stealth technology? And why don't we have any other examples of such weaponry other than Russian one?


texts: Why are updraft carburetors standard in aviation?

texts:
My only detailed experience with carburetors is in aircraft. I'm pretty familiar with the principles behind float-type carbs, but I recently saw a schematic for a "downdraft carburetor" with a choke valve. This got me curious, so I did a little research and found that what I'm used to is an "updraft carburetor", and that (according to wikipedia) they fell out of fashion in the automotive industry in the 1930s.

Why is the updraft carburetor design so prevalent in aviation? Does an updraft carb actually have a choke valve?

Images below to provide a little context for those of us who are not engine experts!

Typical aviation carb:

Typical downdraft automotive carb:


texts: Does cargo balance affect fuel efficiency in commercial aviation?

texts:
Positioning cargo such that the center of gravity of the plane is within a certain range is essential, but is there any advantage to having the center of gravity closer to some ideal point within the acceptable envelope?

Would additional control surface drag be caused by cargo loaded right on the edge of operating standards?

Would finding an optimal loading be computationally complex? How many cargo pallets/containers fit in a large cargo aircraft?


texts: How does GPS measure any plane's ground speed?

texts:
How does GPS measure an equipped airplane's ground speed assuming that the plane in question actually uses GPS as opposed to an inertial navigation system or other method?

(This was originally part of another question)


texts: Helicopters: why hasn't NOTAR been more popular?

texts:
NOTAR

No tail rotor: use of a ducted fan within the helicopter's body, and venting the air through the side of the tail boom to get the desired anti-torque.

One big advantage is simplicity and ruggedness: no tail rotor to get damaged, no tail rotor gearbox or driveshaft to wear and/or malfunction.

Another is noise: NOTAR is quieter.

And maybe lower cost: the simpler design and fewer components moving under high torque should be less expensive to build, definitely less expensive to maintain.

One possible disadvantage might be fuel consumption - it is quite possible that the ducted fan and the air turning a corner isn't as efficient as a propeller, so fuel consumption might be higher, but not that much higher. I haven't seen any figures on that, one way or another.

As of today, only Boeing (via purchase of M-D) uses the ducted fan in three MD helicopters, and even they haven't sold that many helicopters with this design. In all my aircraft watching, I have seen only one MD 520N in flight.

I'm just curious - other than maybe patent royalties, is there a mechanical reason this design hasn't been more popular? On the safety and maintenance aspects alone, it seems like a winner. And for military helicopters, the lower vulnerability and lower radar return would seem like big advantages.


texts: Did the Doolittle raid run their engines over square?

texts:
My flight instructor made a comment when talking about complex airplanes that "never over-square an engine" is a good rule of thumb but secondary to POH instructions. The POH, (I presume) is the best-informed source of how the engine was intended to operate.

He then went on to give an example: Supposedly, since the Doolittle Raid had to launch their B-25B Mitchels 200 miles further out to sea, they ran their engines over square which changed their fuel consumption such that they were still able to pull of the mission.

So here are my questions:

Did the pilots during the Doolittle raid run their engines over square?
By what mechanism would running over square change fuel consumption that dramatically? Is that unique to the B-25B's engines?
If there is such a big fuel consumption benefit, why is the "never over-square an engine" rule so prevalent? (Seems like this competes with operating the engine at "best economy"?)

Image of B-25B launching off the USS Hornet:


texts: Can private pilots run other non-passenger flight businesses?

texts:
As I understand it, private pilots can not take paying passengers.
(Friends on a flight can give the pilot strictly only the friend's share of fuel etc. costs.)
But in fact can private pilots

do aerial photography/videography and charge for it?
do reconnaissance/similar and charge for it?
deliver packages, or indeed cargo?
drop skydivers for pay
pull up gliders for pay

What's the deal on that?


texts: What are the B737 MAX 8's OEW and max payload?

texts: I have Googled it, but have not found official info on that.


texts: What would happen if multi engines operated symmetrically?

texts: What would happen if a multi engine operated symmetrically? So if one engine were to rotate counter-clockwise and the other clockwise. What are the advantages and downsides to this?


texts: Why does supersonic flight detach airflow from a wing?

texts:
I've read in several answers to questions that when a wing passes the speed of sound the airflow will become detached from the craft towards the rear quarter of the wing (thus making things like elevators ineffective.)

Why does this happen at Mach Speed?  Can it happen at lower speeds as well (in straight and level flight, ie, not stalled)?


texts: What is "Carson cruise" and can I determine it myself?

texts:
Mike Y. just posted an answer containing the following:

  With today’s fuel costs, the Carson cruise angle of attack, which represents the most efficient way to fly fast with the least increase in fuel consumption, is of significant interest.

Being an outstanding human, Mike also added a reference to the document that it came from:

  "Low-Cost Accurate Angle-of-Attack System", Borja Martos and David F. Rogers, Journal of Aircraft 2018 55:2, 660-665

But for those of us who don't have access to that journal or can't be bothered to go find it, what is Carson cruise?  What exactly are the benefits and how is it determined?  Finally, can I determine it myself for my airplane without an AOA indicator?


texts: Do any airplanes use a 3-axis joystick? Or is the Z-axis twist not mechanically or ergonomically (i.e. cross-axis coupling) viable?


texts: What does "OBJECTIONABLE" indicate on a VFR chart?

texts: On the Tulsa, Oklahoma VFR sectional the top of the outer Class C ring says "OBJECTIONABLE". Does this indicate some information on the chart is in dispute? I don't see anything in the VFR chart legend or side panels about the meaning.


texts: Are passengers more likely to see other airliners from a window seat on the right or on the left?

texts:
From the window of an airline, one is more likely to see a plane travelling in the opposite direction, than one flying in the same direction.

Are planes travelling in the opposite direction more likely to be found on the right or the left? That is, are opposite airways given a left/right arrangement?


texts: Why is the UAE the only country with two flag carrier airlines?

texts:
The United Arab Emirates has two flag carrier airlines, Etihad Airways and Emirates. There are 195 countries in the world, and 147 of them have one single flag carrier airline. United Arab Emirates is the only one with two. Is it just a chance occurrence?

flag carrier airways


texts: How does the FAA define fuel capacity for ultralights?

texts: Ultralights under FAR 103 are regulated to a capacity of 5 gallons. I'm wondering how exactly fuel capacity is defined, does it include fuel in the lines, and in the carburetor bowl or elsewhere or just the tank feeding the engine?


texts: How to determine the RPM of the rotating shaft of an A320 PTU?

texts:
The A320 PTU has an in-line variable displacement pump on one side and a bent-axis fixed displacement pump on the other connected directly by a shaft.
what would be needed to know how fast the shaft turns during PTU operation?


texts: In cases where complete tail surface rotates (be it horizontal, vertical or at angle) what should be preferable axis of rotation of surface.


texts: What are a few main differences between ATC interactions for rotorcraft vs fixed-wing?

texts:
The title says it all. In particular, I'm wondering what the differences are in reference to:

Takeoffs and landing - can rotorcraft be cleared to take-off / land directly from / to the helipad?
When rotorcraft want to head VFR to a location, are they treated like normal fixed wing aircraft (e.g. given an altitude and / or heading restriction)?
In fixed-wing IFR, aircraft are sometimes put into a holding pattern. If a rotorcraft is asked to hold, is it legal for them to hover at whatever location they want?
I think that helicopters are sometimes asked to surface taxi / hover taxi / air taxi at airports to keep everything in order.

Feel free to add any other differences between ATC interactions between rotorcraft and fixed-wing I might have missed.


texts: What are the practical impacts of airports in the US being mostly IATA Level 2?

texts:
IATA classifies airports using levels, which determine how slots are allocated.

Source

Definitions of levels by IATA, from Slot Coordination Switzerland:

Level 1: airports where the capacity of the airport infrastructure is generally adequate to meet the demands of airport users at all times.
Level 2: airports where there is potential for congestion during some periods of the day, week, or season which can be resolved by voluntary cooperation between airlines. A facilitator is appointed to facilitate the planned operations of airlines using or planning to use the airport.

Dublin and Salzburg are Level 2.
Level 3: airports where capacity providers have failed to develop sufficient infrastructure, or where governments have imposed conditions that make it impossible to meet demand. A coordinator is appointed to allocate slots to airlines and other aircraft operators using or planning to use the airport as a means of managing available capacity.

Heathrow, Gatwick, Barajas, Oslo, De Gaulle, Orly, Tokyo, Malpensa, Pearson are Level 3.

Many major airports are level 3, but only one US airport (JFK) has this classification.

Is there a reason US is seemingly deliberately different? What does that mean in term of practical scheduling by airlines? Is the difference apparent to a pilot?


texts: Have there been accidents involving flight simulators?

texts:
Have there been any accidents which have happened to/in flight simulators?
I understand that simulators are used to simulate general accidents for training purposes (engine failure, birdstrikes etc), and also specific accidents for forensic purposes (the first use, in 1972, of a CAE JAT DC9 SIM), but I am wondering if there have been any accidents with the simulator itself? I am thinking of possibly a simulator's motion system failure? or fire? or trainees trapped? etc.
Additionally, if you knew of any source which might keep record of this type of information, that would also be very helpful.
The example that first comes to mind is the tragic 2014 crash of a Beechcraft King Air B200 into a flight simulator in Wichita, Kansas.

Update: To clarify, I am interested in all examples, but those that have received media attention for whatever reason are my primary interest (these stories will be held in the public record and can thus be further researched). Though interested in “work-place incidents”, these would likely have been dealt with internally unless there was a certain severity or sensational aspect.
I have answered my own question for now, will reward answer to someone else if they have any further information.


texts: Has a commercial jet airliner ever stalled on takeoff / at low-altitude?

texts:
In general aviation, a common reason for fatalities is low altitude stalls on takeoff or practising go-arounds.

Has there ever been an incident where a commercial jet airliner stalled on takeoff / at low-altitude?

(Excluding the one where the tank wasn't secured, pretty sure that wasn't commercial anyway.
Also excluding the MAX 8 incidents).


texts: What is the final approach fix altitude for this localizer approach?

texts: As I'm looking at this approach chart, I see that the glideslope intercept altitude is at 1400 feet MSL. However, for the localizer approach, I believe we stay at 1400 feet MSL until RIZER, which we can then descend to our MDA. Is that correct?


texts:
There is an aileron trimmer in some Boeings. When and why should it be used?

P.S. I'm not a pilot, can you answer with less smart words?


texts: How to model the rounded tips of a rectangular wing?

texts:
Here again for my report about the aerodynamics of a wing. Now I am dealing with the Fuji FA 200-180 wings. I am trying to draw the wing in Matlab. This aircraft has a no-tapered rectangular wing, so it seem to be very easy to draw but... but the wingtips are not straight! How can I model this? Jane's All the Worlds Aircraft says that the chord is spanwise constant. No mentions about the wingtips.
Thank you!


texts: How do I calculate the normal component of the velocity at the midpoint of a source straight panel?

texts:
I am reading "Fundamental of Aerodynamics " by J.D.Anderson Fifth edition. Now I am at the chapter 3. If you got the book, please go to the page 286, the part that says: "when j = i, the contribution to the derivative is simply $\lambda/2$ ". How could it be $\lambda/2$ ? I thought it would be zero.

I will summarize the problem for those who don't have the book:

We have a uniform flow and a source sheet cover the the surface of a known body. We have to find out the $\lambda=\lambda(s)$ along the source sheet that when we superimpose the uniform flow with this source sheet, we obtain the streamline over surface of the body.

A source sheet is an infinite number of line sources side by side,
where the strength of each line source is infinitesimally small

We approximate the source sheet by a series of straight panel over the body surface (if we take n panels, then we have to find n values of $\lambda$)  and calculate the velocity at each panel and set the normal component of it equal zero.

Take a point $P$ at the middle of $i$th panel and calculate the velocity at $P$ induced by the panels, or just calculate the normal component of the velocity at P. The book said that the normal component of the velocity contributed by only $i$th panel at the mid point $P$ of this panel is $\lambda_i/2$. I don't know how to calculate this, I have tried and thought it would be zero.

@Peter: Look at the image, you can see the velocity induced at P by the panel i is in the ab-line direction (I mean the horizontal direction). Then, the normal component (vertical direction) of it will be zero


texts: How do the Tiger Moth's anti-spin strakes work?

texts:
As originally designed, the DH.82 Tiger Moth had unpredictable spin characteristics. Many aircraft were lost because spin recovery took too long (i.e. too much loss of height). Many examples of the type have been retrofitted with anti-spin strakes, which extend forward along the top of the fuselage from the empennage. It's shown here on two DH.82a's.

The anti-spin strakes don't prevent spinning completely, but they make the spin more manageable and more predictable. Some operators of the type nowadays haven't added the strakes, because they have found their aircraft to behave itself in the spin even unmodified. There's a theory that the unpredictability of the type was the result of variations in material and construction quality in wartime.

How do the strakes help? What aerodynamic effect causes them to help spin recovery?


texts: Does Part 135 allow single-engine night IFR operations in a turboprop?

texts:
Do the Part 135 rules allow single-engine turboprop night IFR Part-135 operations? If not, then all the night activities of current popular (and expensive) single-engine turboprops are by private or corporate owners and there are no commercial operations...!!!

I understand certain single engine turboprops are allowed to fly IFR at night for hire in EU, but I am not sure about it. Your input is much appreciated.


texts: Why do Western aircraft manufacturers use FPS system while Russian aircraft manufacturers use MKS system for flight instruments?

texts:
Why is there a variation in aircraft flight instruments of aircraft from Western & Russian origin?

Foot–pound–second system (FPS)
Meter-kilogram-second (MKS)


texts: Is Fluid Structure Interaction considered in aircraft design?

texts:
Fluid Structure Interaction (FSI) causes an  aeroplane’s geometry to change and hence the forces on the different surfaces of an aeroplane become different than the forces expected according to initial calculation.

Is this Fluid Structure Interaction considered while calculating
forces (and hence the final design) of aircraft while finalizing
the designs for aircraft?
If it is considered, what are the available software packages which could be used to analyse this?


texts: Do pilots typically mix roll/yaw when piloting various planes?

texts:
When flying on GeoFS, a popular flight simulator online, one of the default settings is to mix roll and yaw. Of course, it isn't real life, so I think it might differ from flying in the real world.
Do professional pilots mix roll and yaw? Is it possible that pilots have different settings for different types of planes, such as fighter jets and commercial jets?


texts: Who pays for the compliance with Airworthiness Directives (AD)?

texts:
Airworthiness Directives (ADs) are legally enforceable regulations issued by the FAA in accordance with 14 CFR part 39 to correct an unsafe condition in a product.

Hence when an AD is issued, owner must comply with the AD within the stated time period in order to remain airworthy. This compliance ,of course, come with some cost. Who pay for this cost of compliance? Owner of the plane? Manufacturer? Or they somehow share the cost?


texts: How can I mount my iPhone 6 in the cockpit to record my flights?

texts:
I am a student pilot, and would like to record my training flights to look back on. I do not have a Go-Pro, and do not want to fork over the money for one. I do however, own an iPhone 6, that has a pretty good camera. I was wondering if anyone had some ideas as to how I could mount my phone in order to record my flights? I thought maybe a suction mount would be best, as I could mount it behind my shoulder on the back of the glass cockpit (Cessna 152)

If possible, it would be better if it could record my control inputs throughout the flight. Please let me know if anyone has found a working solution in the past.