texts: Turbo-electric engine vs high by-pass-ratio Turbo fan, which config. would seem more efficient? (Liquid Hydrogen Fuel)

texts:
Would be a turbo-electric config using 2 turbofans as generators for a 150 pax. aircraft more efficient than a very high bypass rationed Turbofan that burns hydrogen?
If not, then why are all companies like Airbus, Rolls Royce and Safran etc. working towards this?
Also, why would they just use their Highby pass Turbo-fans, that ways they don't have to invest billions and also have very high efficiency and less pollution (CO2, Nox, etc.)?
If we can argue about 15 years down the line, what would be a better solution? And why?


texts:
Any further information is welcome, this is what I have learned so far:

Engines are designed to operate at a certain RPM (N1). The compressor consists of small 'wings' which are fixed in position, so the angle of attack will vary only by engine speed and forward speed. The engine design speed should be 85-95% N1 for most turbofan engines, this results in an optimum airflow through the compressor. Above or below a higher risk exists for an engine to stall.


texts: What is the source for the "rule" forbidding configuration changes below 200ft AGL?

texts:
I keep hearing from countless instructors, and even some DPE's, that in single engine aircraft, no configuration changes are allowed below 200AGL (i.e. flaps).

Some have also stated that this is when a single engine is supposed to be stabilized, despite the 500/1000AGL rule for VMC/IMC approaches respectively.

What's confusing is this is used from instrument approaches to power-off 180's, yet I've heard people use the last notch of flaps to "bump" them to their point.

Does anyone have a source on this 200' rule? Any help is appreciated!


texts: What type are these planes that are flying in formation near Culver City, CA?

texts: My son in law took these images a few days ago in Culver City California. We would like to know what the vintage (WWII ?) planes are, and in the last image, what would cause such a contrail. The last image is a composite of several shots. (Something landing at Edwards was my guess). His guess for the aircraft are that they are all the DB Dauntless.


texts: Where is the pitot static drain located on a Piper PA-28?

texts:
Some PA-28 airplanes have pitot static drain where the pilot pushes 2 buttons to open the system.

But where does the water drip out from the airplane? Is there a hole underneath the airplane? Where?

I mean when you push the buttons where should you look for water coming out?


texts: What are the legal issues for an Uber or Lyft type model for ride share on General Aviation aircraft in the United States?

texts:
Is it possible for an Uber or Lyft type service to operate that allows pilots with small aircraft to share a ride under current FAA regulations? I personally don't see how this could operate under 14 CFR 91, but maybe under what's allowed under 14 CFR 135.

I haven't been able to identify exactly what companies are trying, but I've been hearing that something like Uber for small planes is under development. This has caused great skepticism on my part that a company could accomplish this because of the regulatory requirements involved.


texts: What is the typical touchdown vertical speed of a large airliner?

texts: What is the vertical speed (range) of a Boeing 787 (or any other large commercial aircraft) that should be achieved just before and during touchdown? I'm not interested in the vertical speed during the approach, my question only targets the last 100 feet before touchdown... this includes the vertical speed after the flare. Obviously a vertical speed of 0 fpm is desired for comfort reasons, but as I understand (see also this question), aiming for 0 fpm makes it difficult for pilots to aim at an optimal touchdown point on the runway.


texts: What is the first fighter jet aircraft which carried out a night bombing mission?

texts: Does anyone know in which occasion it was carried out and  the date which it was carried out? Night bombing began in World War I and was widespread during World War II. A number of modern aircraft types are designed primarily for nighttime bombing, but air forces no longer refer to them as night bombers. More common terms today include interdictor and strike fighter, and such aircraft tend to have all-weather, day-and-night capabilities.


texts: Does shutting down the engine affect the rate of rotation during autorotation?

texts: If a helicopter's tail rotor shears off while flying then the helicopter's fuselage will start rotating in the direction opposite to the main rotor's rotation direction. During autorotation, if I switch off the engines of the helicopter, then will it affect the rate of rotation of helicopter?


texts: What emergency situation can pilots encounter in gliders/non-powered aircraft?

texts: Pilots have to be able to handle a wide range of emergencies in the air. For powered aircraft, the obvious example to me is recovering from an engine failure, but obviously this can't happen on an unpowered glider. Many gliders have no electrical systems, so an electrical failure can't happen. A stall, I believe, can, and I assume the recovery would be similar to in a powered aircraft. What other emergencies should a glider pilot be able to handle? I'm especially interested in any emergencies that powered aircraft don't have to deal with.


texts: Why would an airplane be approved for ditching?

texts:
So, the Learjet 60 that I used to fly has the following limitation:

My question, is why would a manufacturer certify an airplane for ditching if it isn't required?  The airplane is most likely going to be totaled anyway, right?

Or does it just mean that since it isn't certified for ditching that we aren't allowed to do it?  Guess no double engine failures over water will be in my near future....


texts: How do engines cope with various intake airflow speeds?

texts:
On a recent trip out of Washington Dulles to San Francisco, our B777 met with 200+ mph headwinds (as per the passenger entertainment system) at 35,000 ft for the first half of the route, before enjoying 50 mph tailwinds at 38,000 ft over Utah, Nevada and finally California.

The ground speed was displayed at 400 mph for the first half of the trip, then closer to 550 mph. Does that mean that air was rammed into the engines first at 400+200 = 600 mph, then in the second half of the trip at only 550 - 50 = 500 mph?

How do the engines cope with various intake airflow speeds?


texts: What is the viability of stacking passengers in an airplane cabin?

texts:
I've came across on youtube a new design for stacking passengers in an airplane cabin, that looks at first sight interesting.

What would be the advantages and drawbacks of such a design? Why this is not common in today's airplanes?


texts: I would like to know what makes a brushless motor heat up. I'm aware of the problems generating the high temperature such as wire contact problems or overloaded motors. I want to know what makes a normal motor in normal conditions warm up. Is it related to the Joule effect?


texts: What are acceptable treatments for chronic pain that will not result in a loss of an FAA Medical?

texts: Is there an acceptable treatment plan for neuropathic pain? Gabapentin is not an acceptable drug. Lyrica and Cevalla aren't approved. Is there a treatment that could even get a special issuance?


texts: Does flow separation starts earlier at higher airflow speeds?

texts:
For same AoA,will flow separation starts earlier (point of separation more upstream) at higher airflow speeds (=higher air inertia) compare to lower airflow speeds?
High speed airflow has more air inertia so it seems inuitevly that air will harderd follow curved surface and leave surface earlier?
Question referes to subsonics speeds,but you can expand your answer at supersonic speeds as well.
Same topic at physics site,but we heve problem here because members have opposite oppinions:
https://physics.stackexchange.com/questions/602876/does-flow-separation-starts-earlier-at-higher-airflow-speeds/602888?noredirect=1#comment1356599_602888
??


texts: What will be in 'radiotelephony privileges' part of EASA PPL without practical RT examination?

texts:
My question is addressed to pilots who recently obtained PPL in Europe (preferably in Czech Republic, but not so important).

As I understand, EASA itself does not require separate radiotelephony license (FRTOL, RT etc.), but some EU states does.

Does anybody have any recent experience in obtaining EASA PPL in Europe (especially if it is not your domestic country)? What do you have in the 'radiotelephony privileges' part of your license? Have you had to pass a separate practical RT exam?

NOTE: I do not consider UK.


texts: How do I calculate the lift force on an aileron?

texts: How do I calculate the force of lift acting on an aileron with a deflection of 8° and a flight speed of 40km/h?


texts: How do you lean mixture using only the instruments on a C172 Skyhawk?

texts:
POH manuals always tells to use the voice of the engine as a reference. (Which complicates things a little bit since carbs and fuel injected planes have different "reaction times" for each cylinder)

But how do you lean the mixture without using your ears? How do you lean mixture with only the instruments as a guide?

Lets assume we have a brand new C172 Skyhawk


texts: Why are the leading edges of the 787's horizontal and vertical stabilizers not painted?

texts:
The other day I made a question about the engine painting and why it isn't painted at the front part. The answer was: to facilitate anti-ice system.

Source: fervegeon.com

So perhaps the leading edge of the horizontal and vertical stabilizer have a sort of anti-ice system?

And this is not only on the 787; the 777 also has the leading edges unpainted.

Source

And on the 757 and winglet.

Source: flickr


texts: Can I log PIC time when training for a tailwheel or high performance endorsement?

texts:
If I hire a CFI to train me for the tailwheel endorsement (this question also applies to the high performance endorsement), can I log PIC time when flying the tailwheel aircraft, or do I have to log dual received?

This question is specifically about FAA rules related to training/logging time, but if there are different rules in different countries, feel free to answer about those too.


texts: What would happen if you turn on all air vents simultaneously?

texts:
Sitting on the plane yesterday, wanting some fresh air and boom it hit me [literally]. What would happen, let's say both static and mid flight, if everyone turned on there air vents at the same time?

Could the unit handle all of it simultaneously, would it effect pressure, I'm not privy to the working of air units of aircraft so it may be a silly question but it's still a question that I'm interested in knowing the answer to.


texts: Do I have to notify someone or file a flight plan for a private flight in the UK?

texts: Say I have a private pilot's licence (PPL) and I want to go on a flight, say from Stapleford (ICAO: EGSG) to Damyns Hall Aerodrome (ICAO: EGML). What would be the procedure for the journey i.e. would I have to notify anyone or submit a flight plan to the CAA?


texts:
I'm just a Flight Simulator player with no real-life flying experience, so I apologize in advance if I'm asking a stupid question :)

I watched a TV show and saw that certain courier companies (DHL for example) tend to have multiple shorter flights with refueling instead of one long flight with larger initial amount of fuel, because in that way they burn less fuel.

Then I started thinking about the relation of fuel quantity and the range of an aircraft. On one side, the more fuel an airplane has, the longer range it will have. On the other side, more fuel means more weight, which will then increase the fuel consumption (but both the weight and the consumption rate will decrease gradually during the flight). Of course, let's observe a theoretical case, where the plane has constant speed and altitude, and there is no wind.

Is there any equation/graph for a certain aircraft type which shows how much fuel is "too much", i.e. if there is a "sweet spot" which will give the best ratio of fuel consumption and flight range?


texts: Statistically, how safe are para-motor craft compared to other GA planes?

texts: I know there are very well kept records for death and accident rates in GA aircraft, but I was wondering if there were numbers for para-motor aircaft that are easy to compare?


texts: How many commercial passenger aircraft suffer tail strikes in a given year?

texts:
This is inspired by a lengthy set of comments on this question (for reference).

I've been searching the internet high and low for reliable information on how many tail strikes occur per year for commercial passenger aviation, and I can't seem to turn up anything reliable.  Articles I've read range from saying they happen maybe once a year to several times a year, but none of them show hard numbers or list all incidents (here, here and here for a sampling.)

If anyone has verifiable hard numbers on this, I would love to see them...


texts: What is the physical-based/theoretical reason why supersonic area ruling works?

texts:
Supersonic area ruling is used to reduce the drag rise that occurs as aircraft pass through the transonic regime. While it has been validated experimentally, what is the theoretical/physics-based reasoning why area ruling reduces the drag?

I know that the following answer suggests that it is simply a "rule," but could someone shed more light into WHY the area ruling technique works? (What is the "area rule"?)


texts: How to perform an operational test on the attitude and heading indicators?

texts: I just need to know how to perfom it. The only thing I know is that you have to remove them and take them to a "lab".


texts: What were/are the military designations of the JT8D and PW4000?

texts:
Turbine engines on U.S. military aircraft, in addition to their manufacturer-given names, receive separate designations (consisting of J [for turbojets], F [for turbofans; formerly TF], or T [for turboprops], followed by a number) for internal military use (examples: JT3C/J57, JT4A/J75, JT3D/TF33, JT8A/J52, JT9D/F105, PW2000/F117, JT12A/J60, CJ805-3/J79, CJ610/J85, CF700/TF37, CF34/TF34, CFM56/F108, CF6/F103), even if the military engine is completely unchanged from the civilian version known universally by the manufacturer-given name.
For most engines, information on their various names is readily available; however, I have been unable to find the military designations of two Pratt & Whitney turbofans currently-or-formerly-used on U.S. military aircraft (the JT8D low-bypass turbofan, used on the T-43, C-9, and YC-15, and the PW4000 high-bypass turbofan, used on the KC-46).  Does anyone here know the answers to this puzzle?


texts: Is the ATR empennage configuration considered a T-tail or a cruciform tail?

texts:
How is the ATR 42/72 empennage considered? Is it a T-Tail or a cruciform tail?
From the image the elevators are placed quite high on the tail that they can be considered as a T-Tail but is it so?

Looking at the tail of a 727 the elevators are placed at the top of the tail but just leaving the space for the mechanism to move them, whereas on the ATR they are placed in a slightly lower position.

Are there any technical specifications and measurements that clearly define the difference between the two mentioned configurations?

I understand that cruciform means "similar to a cross" but it would be interesting to know, as previously mentioned, if there are specifics about this definition making it clear for everyone from a technical point of view. (briefly, when does a T-Tail become cruciform?)


texts: What is the correct procedure for overwing fueling a CRJ200?

texts:
I have a question regarding overwing fueling a Canadair CRJ200. Let's say I was pressure fueling and one of the wings started venting fuel on the ground. The Crew Chief determined that I had to overwing fuel the wings, and then finally the center tank.

My question is: exactly how much fuel in gallons can I load into each wing before I should move back to the other wing and start fueling? Meaning, what is safe so that there is no tipping of the aircraft after fueling one wing and then moving to the other to also save time from going back and forth more times than needed to achieve desired amounts in each wing?

Say the Right tank has 2450lbs, the Center tank has 0 and the Left tank also has 2540lbs. I have to start overwing fueling and the pilot's order was for 12,500 lbs total. How many gallons should I start fueling with in (say) the Right wing before I move back to the Left wing and then back to Right again etc.? And then then finish off the Center tank?


texts: Past depression affect my ability to obtain a Canadian medical certificate?

texts:
I'm from Canada, and two years ago I had problems with my wife and decided to divorce. After that, I felt discomfort, and I was diagnosed with depression.

I took an antidepressant Effexor for one year. But another doctor decided to stop my medication because he believed that it was normal to be sad after divorce, and I lm not a depressed person! so I have taken no medication in the last year. I think that the first doctor had made a mistake by giving me this medication.

Should I still be able to qualify for a medical 1 in Canada?


texts: Will portable Stratus ADS-B In receivers operate normally from the passenger cabin of a commercial airliner?

texts:
Are ADS-B In receivers such as Stratus or Stratux permitted to be used along with other portable electronic devices at cruise altitude on commercial airliners? Will they receive GPS and ADS-B signals in the passenger cabin to be able to track progress on ForeFlight, for example?

Source: Appareo


texts: Why don't modern F-16s incorporate the VISTA thrust vectoring?

texts:
Modern incarnations of the F-16, such as the Block 70/72, F-16I and F-16IQ appear to incorporate many modern technologies. These aircraft are also rather different from the original F-16A, being heavier and more of an all-round fighter than a dedicated air superiority aircraft.

With heavy wing loading and a heavier aircraft overall, why was it considered to drop incorporating thrust vectoring into the F-16, to retain more of its dogfighting capability? This is hardly new technology to the F-16, considering the VISTA first flew in 1992.

This appears especially interesting considering highly maneuverable opponents such as the emerging J-20, Su-57; but also older fourth generation aircraft. The Typhoon, Rafale, Su-37, J-10, and others, are all roughly in the same ballpark as the more modern (heavier) F-16s, correct me if I'm wrong.

Does this indicate that dogfighting is a thing of the past? How can this be, considering that the F-22 was designed to be supermaneuverable? This appears to be a contradiction to me.


texts: How is an off-field landing accomplished at night?

texts: Common sense suggests it's much easier to do an off-field landing at day than at night, curious to know how it's accomplished at night.


texts: What is the fuel source for the APU on a B737?

texts:
Where does the fuel come from that powers the APU on a 737? My understanding is that it is from the left front main fuel tank, but I've also heard, hearsay, it can have it's own source. I know that the methods for getting the fuel to the APU can vary: GPU, gravity feed, main tank switch. But where does the fuel come from?

Thank you


texts:
I'm working towards my tail wheel rating and enjoying it greatly. But, people ask me why some planes have a conventional landing gear (tail wheel).

Why indeed? I understand perhaps why they had them originally, but is it just historical reasons? Seems like maybe it can have slightly lighter gear and perhaps simpler design, but I'm wondering if there are deeper reasons.


texts: Why shouldn’t the A330/40’s speedbrakes be used in alternate law?

texts:
On page 30 of the ATSB report into the QF72 accident (page 50 of the PDF file of the report), in a table describing the actions required of the flightcrew in response to some of the ECAM messages displayed during the flight, there is the following entry:

ECAM message [...] Required actions
[...]
F/CTL ALTN LAW (PROT LOST) [...] Do not use speed brake [...] Maximum speed limited to 330 kts / Mach 0.82

[ATSB Transport Safety Report AO-2008-070, page 30 (PDF page 50), Table 6.  Table headings bolded in original; all other bolding is my own.]
Why aren’t the A330/40’s speedbrakes (the term used for the aircraft’s flight spoilers, when deployed symmetrically to increase the aircraft’s drag and reduce its lift) supposed to be used when in alternate law?


texts: Why is rain above freezing level (altitude) not always "freezing rain"?

texts:
How is rain that is encountered ABOVE the freezing level (altitude) not always "freezing rain"?  And how commonly does this occur?

Situation: Light rime ice in forecast (approximately 10-15K MSL(?)), so freezing level about 10K.  Climbout through forecast light rime and did not get any ice at all.  None.  Kept climbing, initially VMC but then encountered IMC somewhere around FL180(?) and then encountered rain.  (Been in snow once and this didn't look like snow.....BTW, no snow in forecast at all.  No freezing rain in forecast, either).  Smooth ride/no turbulence.  Kept climbing to get above rain due to altitude being above freezing level.  NO ice formation/accumulation at all.  Climbed all the way to FL280 before broke out of IMC/rain.  NO/ZERO ice accumulation.  How is this possible?


texts: What should I do after failing the oral portion of my private pilot check ride?

texts: What steps should I take after failing the oral portion of the check ride for my PPL?


texts: Why is the delta wing naturally stable in pitch?

texts: Any thoughts on why the delta wings are naturally more stable in pitch, so they don't require any tail surface? What's the physics behind this?


texts: What is the minimum turning radius of an SR-71?

texts:
What is the minimum turning radius of an SR-71 at Mach 3.2 and an altitude of 80,000 feet?

I have heard that if an SR-71 were to cross the Pacific coast over San Francisco and pull a hard turn to the right, it would return over Seattle.

I'm interested in real-world performance, taking into account things like inlet unstart (failure to capture the engine inlet shockwave in the intake) from too sharp an angle of attack.


texts: Why doesn't ATC use a unified frequency for the same control area?

texts:
If you have experience of getting flight following or flying instrument in the US, you might have noticed that approach and center controllers alternate between two or three frequencies for the same control area. For example, I get 118.1 from the tower for flight following one day, and the next day I get 126.0 for flight following for exactly the same route of cross country.

Why don't they just use one frequency for the same control area? Wouldn't that make their job much easier?


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

texts: What metal alloy is used for the hot section of a jet engine? Specifically the exhaust nozzle? I have found mention of a titanium alloy and nickel alloy but nothing with that much detail. What sort of metals does one have to use to create something that can withstand temperatures of 650 degrees Celsius? Thanks


texts: How did this Boeing 787 perform this near vertical takeoff?

texts: At angles of attack like this an airliner would stall very easily. The 787 wing would stall at an angle of 30 degrees. The plane would have been flying at speeds of around 200mph(more likely less) at this angle and speed the aircraft would be very susceptible to stalling? How is this even possible to perform this without stalling? Source:youtube The a380 also performed this near vertical takeoff.Source:Youtube


texts: Is it true that a soda can or a bag of chips will pop in a plane at high altitude?

texts:
I've heard some conspiracy theorists claim that if you were to bring a soda can or a bad of chips onto an airplane, they would pop?

Is this true? If so, why?


texts: Must RAIM be checked in flight before every GPS approach or is a preflight check acceptable?

texts:
My instructor has been teaching me to run a RAIM check for each RNAV approach we do.  For some flights this can be 4 or more RAIM checks for the various airports/approaches and adds significantly to the workload.

I started doing some research and I think I've gathered a few things. First RAIM applies over large areas, not singular GPS points (makes sense), the FAA provides a tool to determine RAIM availability from the ground as part of preflight, and last that a RAIM check while briefing the approach seems Like it might not be necessary since the GPS is required to run a RAIM check 2 miles prior to the FAF.  Additionally since the GPS has no way to know about unexpected NOTAM announced outages the 430 RAIM precalculation is a bit less reliable.

Is it a requirement to run the manual RAIM check in flight or is it more appropriate to use the FAA tools and determine it as part of preflight preparation?


texts: Can I log simulated instrument time in a complex plane without having a complex endorsement?

texts:
My safety pilot is endorsed for complex, and will be PIC for the entire flight. I would also log PIC for the time I spend under the hood.

I will eventually get my complex endorsement, but insurance is much cheaper if I have time in type, so in the long run it will be cheaper for me to build time in type and work towards my instrument rating at the same time.


texts: What does the last 'B' in 'GEnx-2B67B' stand for?

texts:
What does the last 'B' in GEnx-2B67B stand for?

I guess it stands for Boeing, but the GEnx-1B series doesn't have it.


texts: How does turbine efficiency compare with internal combustion engines if all the turbine power is converted to mechanical energy?

texts:
It is widely know that early turbojets guzzled fuel and created thrust simply by spewing accelerated matter out the back.  Modern jets have come a long way in earning a better reputation with efficiency improvements.

If an aircraft mounted the exact same propeller on a supercharged piston engine and a turbine, and flew under identical conditions at the same pitch and rpm, how much more fuel would the turbine use (possibly including weight savings benefits for extra credit).

I am picturing a two engined aircraft with the two types of engines flying side by side at around 350 knots.


texts: Does holding a medical certificate mean you automatically have a student pilot certificate?

texts: If you have a 1st, 2nd, or 3rd class medical certificate and a private balloon certificate (as an example) does that mean you have a student pilot certificate if you now want to get a private pilot certificate? Would you have to go back to a medical examiner, DPE, or FSDO to get a student pilot certificate?


texts: What's the minimum cruise speed of modern airliners?

texts: Often when approaching landing, I feel the aircraft slow down considerably, it hasn't landed yet, but kind of hovers around waiting for clearance to land. Thus I was wondering, is there any defined minimum cruise speed for airliners.


texts: How heavy are the folding wingtips of 777x?

texts:
To understand the mass penalty that is induced by a folding wingtips, as a first order approximation we can start with just the wingtip's mass without the actuating mechanism.
I could not find the 777x wingtips' mass anywhere. Are they the same as the 747 winglets?


texts: Why was the Spitfire's elliptical wing almost uncopied by other aircraft of World War 2?

texts:
The Spitfire was one of the most successful designs of its day, with flying qualities of a similar standard to the other best designs of the era. In its decade of production from 1936 it grew bigger, stronger and faster.

Yet there seems to be almost no appetite from any of the major aircraft-manufacturing powers to emulate its most iconic feature. In fact, there is only one mass-produced aircraft of that time with an elliptical wing, the American P-47 Thunderbolt. Nothing German or Japanese, and nothing more from the British either.

In a period where every manufacturer was trying to gain every last bit of advantage, it seems odd that a prime design feature attracted so little appetite to copy.

There are good explanations here on the aerodynamics or performance of the elliptical wing. Why is it so rare when it demonstrably works so well?

Source


texts: Will Tower repeat an initial heading if it's part of my IFR clearance?

texts:
If I get an initial heading to fly in my clearance from Clearance Delivery, but the Tower controller does not repeat the heading to fly in my takeoff clearance and I stay on runway heading, can the FAA take enforcement action against me (aka did I do something wrong)?

Is the Tower controller obligated to repeat the heading to fly in my takeoff clearance, or is it expected that I do what was in the clearance issued to me?


texts: Why did this old Japan Nakajima J1N airplane use a Yagi rather than a parabolic antenna?

texts:
Picture source.

As per my understanding, a Yagi antenna is a directional antenna with limited gain, which it broadcasts or receives the microwave signal to and from the front side. It can only receive signal if the transmitting antenna is not exactly in front of it, or can receive with limited/very limited quality, depending on the direction. Parabolic, however, has better reception than Yagi.

My question is, why did this old Japan Nakajima J1N airplane use a Yagi rather than a parabolic antenna?


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

texts:
Just to make sure if I am right before I get in trouble.

If I am taking off from an uncontrolled airport for IFR flight, assuming I received IFR clearance on the ground, can I enter into the clouds before I contact approach (or center) after takeoff? Even when the Golf starts at the surface or 700 ft?

Would clearance give me a heading and altitude that I would want to follow right after takeoff?


texts: Within the US: When, and by whom, is the Transition Level determined/published?

texts:
There are several SE Q&As that deal with the terms Transition Altitude, Transition Layer, and Transition Level.  The very-brief, paraphrased definition of the Transition Level (TL) is:

  The lowest usable flight level that can be assigned, and the point at which aircraft descending out of the flight levels will change their altimeters back to QNH.

Due to atmospheric pressure variations, the TL can vary from day to day and (maybe?) region to region.

My five questions about the Transition Level are thus:

Is the entire US using the same TL at any given point in time?
Or, are individual ARTCCs setting their own TL based on the lowest QNH reading in their geographical area?
Or, are individual sectors within an ARTCC setting their own TL based on the lowest QNH reading in their even-smaller geographical area?

If the individual sector controllers are NOT making the determination "on the fly", I then assume that the TL is determined by a "higher authority" and published to all controllers/sectors/centers under that authority. Which leads to the fourth and fifth questions:

Who (what level, position, etc.) determines the TL?
When, or how often, is this determination made?


texts: Is a powerback allowed by airlines as a safe maneuver?

texts:
I watched some videos on YouTube where the pilot used the thrust-reverser for push-back instead of the push-back tug. Some examples:

MD80 Powerback

DC9 Ground Reverser Powerback

Is this procedure currently in use? Would an airline today certify a 737, or even turboprop, like a Beechcraft 1900D, to execute such a maneuver?

I've also seen a Boeing 727 video. 727s and MD80s have the engines attached directly to the fuselage, not in the wings. Would that be one of the reasons?


texts: Is it possible to determine the mass flow rate through the engine of MiG-21 during its various cruise Mach no. operations?

texts:
Is it possible to obtain the mass flow through the Tumansky R-25 turbojet engine mounted on a MiG-21 during its various standard operating (cruise) Mach numbers?
Note: standard as in older planes where there were just 3 positions of the inlet cone - upto Mach 1.5, between 1.5-1.9 and above 1.9.

Also, what should be the cruise condition for this plane, given that it is capable of flying at various Mach numbers and thus speeds?


texts: What kind of supervision do new captains get on their first flight?

texts:
Is there any special consideration for the first flight as a captain? I mean, the first officer gets promoted to captain, does his/her first flight gets supervised by any special way?

PS: I'm tagging this question as faa-regulation, not so sure if it is correct.. please correct me if I'm wrong


texts: Why do we say certain things three times (e.g., "Mayday, Mayday, Mayday"), rather than two or four?

texts:
Repetition is a key characteristic of communication in the control tower, cockpit, and control room.  Some phrases, like "Mayday" get repeated. The speaker says the same thing three times. We know this is for redundancy.

Why exactly three times?

Why not twice or four times? Is there research suggesting three is the most effective number, or is there a historical reason for the convention?


texts: What is the difference between an aircraft main battery and standby battery?

texts:
I have just seen a diagram where it shows both a main battery and a standby battery however I am unsure what the differences are?

I thought the main battery was there as an emergency power source / APU starting etc.. so what is the standby battery there for? Or is it a secondary back up?


texts:
Since it cannot be expected that the materials used for aircraft contruction have infinite lifetime and sooner or later they will deteriorate, how does aircraft maintenance work?

Are there schedules based on which certain components have to be checked or substituted in order to prolong the aircraft lifetime? Will the aircraft be unusable anyway after a certain amount of flight hours?


texts: How is bleed air used to start a jet engine?

texts:
I know that most jet engines on commercial jets are started either with bleed air from an APU or bleed air from the other engine...  But I'm not exactly sure how bleed air actually starts the engine?

Is the bleed air just being blown into the compression chamber?  Or is it being used in some other way?

As a starting point, this question here has an answer that describes the entire process of starting a jet engine on a high level.  It includes a short section on bleed air:

  Through the opening of bleed air valves, bleed air is sent to an air turbine starter. These devices typically use the high pressure bleed air to spin and engage a centrifugal clutch connected to the engines accessory drive. This in turn causes the N2 shaft within the engine to spin.

But I'm hoping for a more detailed explanation on what the bleed air is doing, how (and where) the clutch is applied (is there a transmission as well?).  Problems that may arise, and how they are dealt with.  Etc etc...  I just would like more detail if it's possible.


texts: Why do airfoil's trailing edges point downward?

texts:
The trailing edge of and airfoil is mostly pointing downward. Is there any reason for that? Down wash increases drag and down wash is due to the direction of air pointing down. If the trailing edge is made horizontal (or maybe pointing upward), they can produce less down wash and Kutta Condition can still be satisfied.

What are the specific reasons for this shape?


texts: What is the range and accuracy of ATC radar systems?

texts:
What is the average range, accuracy, and update frequency of radar systems used to monitor airspace in the USA?

I'm primarily interested in capabilities for tracking smaller general aviation aircraft without enhanced return data channels like ADS-B, etc.

Please include sources, if possible. As an example, by looking at TRACON/ASR data exports (CDR), these systems appear to update an aircraft echo at about a 4.7 second frequency, give or take a few tenths. However, I not been been able to source or verify my findings or similar statements made by expert witnesses in litigation cases.


texts: Why are turbine blades not made out of titanium, only compressor blades?

texts:
According to this video on jet engine blades, titanium is never used for the turbine, because it "melts and burns at the temperature of the flame". Only the blades of the compressor are made of this material.

However, the melting temperature of titanium is higher than that of any steel alloys I could find, and titanium produces a protective layer of oxides on the surface. What other properties of titanium make using it impossible?


texts: Re old (1992) US VFR sectional charts-- when was the thin dashed magenta line first used?

texts:
When did the thin dashed magenta line, currently used to illustrate Class-E-to-surface airspace, first appear on the legend of US VFR sectional charts?  I'd like to narrow down the date as precisely as possible. Currently I'm aware that this marking DID appear on the legend of a sectional chart (Hawaiian Islands) effective November 12 1992, and did NOT appear on the legend of a sectional chart (Bethel Alaska) effective August 20 1992.  Please post the "effective date" of any US VFR sectional chart that you are aware of before November 12 1992 in which the thin dashed magenta line does appear on the legend, or the "effective date" of any US VFR sectional chart that you aware of after August 20 1992 in which the thin magenta line does not appear on the legend.

Note that on the legend of the November 12 1992 chart, the thin dashed magenta line is identified not as depicting "Class E airspace", but rather as depicting "Control Zone at airport without control tower and Control Zone extension without communications requirement".  The term "Class E" didn't show up on legend of US VFR sectional charts until 1993.


texts: Are 'human factor' specialists consulted during the UX design of cockpit controls and avionics?

texts:
I have always been struck by the complexity of cockpit controls. Aviation specialists are always on the hunt for ways to reduce cognitive overload on pilots to reduce human error.

That being said, air crash investigations have proven in a number of incidents that labelling, controls interactivity, affordances and other interface design issues impact on how pilots operate.

So, I have few questions:

How do human factor specialists and user experience designers differ (or not) when it comes to designing for avionics?
If user experience design skills are so different from human factor skills, wouldn't they be required when designing avionics?
If they are not so different has anyone came across a situation where user experience skills were utilised within the aviation industry?


texts: Are old illegal air transfer methods still feasible today?

texts:
A retired soldier told me he used to know people who smuggled jewelries, hard drugs, guns and even people from middle eastern countries to Europe, specifically, Germany! Via planes! In fact, he said some goods were too valuable for them to "risk it" by land transports.

He also added that the aircraft were operated by experienced World War II pilots who specialized in flying at high speed in very low altitudes to make deliveries for infantry units on distress, making them unnoticed on radars and unstoppable for air defense systems.

Are similar methods still possible to this date? if not, what has changed?

similar: How do people smuggle stuff with private airplanes?

NOTE: I have researched myself and so far couldn't find evidence that any sort of actual "improvements" were done in these 70+ years in this matter, it seems the security tightens only when it's demanded and new technologies are not consecutively being used to monitor the skies.

no duplicate of Can someone actually "fly under the radar"? (read comments)


texts: Is it possible to use thrust reversers to taxi backwards?

texts:
Can commercial airliners theoretically taxi backwards using reverse thrust?

If this is possible, why isn't it common?

I can already imagine some safety reasons...


texts: What are the primary and secondary flight controls for the SEPECAT Jaguar?

texts: What lift augmentation devices are used in the SEPECAT Jaguar? I couldn't find any information.


texts: Should one use mainly the rudder or the ailerons combined with rudder to go back to center line on short short final?

texts:
My pattern work is improving but there is one thing I consistently miss: I have a very hard time staying aligned with the runway on short final, say after passing the airport fences. When the nose points left or right, should I correct primarily with rudder or with ailerons using rudder just as usual to stay coordinated?
Cross wind is not a factor at this point because I miss even when wind is calm.


texts: How does ATC deal with apparent compass errors when giving vectors?

texts:
Pilots should strive to fly precisely, but we sometimes reach task saturation.

When ATC gives a heading, receives the correct readback, but observes a 10- to 15-degree difference between the actual and intended tracks, does the specialist incorporate this difference into future vectors? Do approach and traffic separation vectors generally have a healthy margins of error?

How does apparent compass deviation or directional gyro precession factor into vectors that ATC issues?


texts: Why are these spec and serial numbers blank on a part's plate of a WWII US military plane?

texts:
These pictures are of a plate from WWII US military plane that crashed in the high mountains of central Japan.

People living there say that after the war officials recovered the crash sites and some parts were put on display in a museum nearby.  This plate is attached to a small metal box which is part of the museum collection.

It says "gear box type JH-1045" manufactured by "Jack & Heintz, Cleveland Ohio".

But SPEC. and SER. are blank.  I assume these are where the spec number and serial number should go?

It looks like somebody carefully cut those parts off the plate.  People there say that was not done after the recovery, so the plane was flying with this plate as it is.  Nobody remembers the type of aircraft nor where the rest of the wreckage went.  I do not know whether the numbers were scraped off before flight or were just originally not there.

Why are these spec and serial numbers blank on the parts plate of a WWII US military plane?

Regards,
Naoya


texts: Could a runway include a safety device to destroy a plane's landing gear?

texts:
The NTSB recently released its final report of a crash at Hanscom field (KBED) in Bedford, MA. The short of it is that the pilot tried to rotate with the gust lock engaged, preventing the plane from lifting off. It rolled past the runway and finally crashed into a ditch, where it burst into flame, killing everyone on board. (I should say that although I've flown in a small 4-seater a few times, I'm not a pilot — so please forgive me if I misused some terminology.)

One thought I had is that if the landing gear had been destroyed at the end of the runway, the crash could have been a lot less severe. In particular, I was thinking that a small wall could have been designed to knock the gear out, making the plane start skidding on its belly and presumably coming to a stop much sooner. It wouldn't be exactly safe, but it seems like it would be safer than relying on just the gear's braking power.

Does such a device exist at any airports? And if not, has it been considered and rejected for some reason?


texts: What does METAR show when actual RVR is below the reporting minimum?

texts: RVR is measured between 50m and 1500m (ICAO). When the actual RVR is below 50m, what does METAR show?


texts: Regulatory Documents To Carry Medical Kits and Defibrillators On-Board

texts:
Are there any regulatory release documents applicable to Medical Kits and Defibrillators? Question is for Commercial Airlines.
For example for:

Components, you are required to have an EASA Form 1 or FAA 8130-3 release tag.
Standard Parts, you can accept with a CoC (Certificate of Conformity/Conformance).

What are similar standards for Emergency/Medical Equipment?


texts: Will the Boeing 737 be built with a geared turbofan engine?

texts:
I've been excited about the potential impact the new Pratt & Whitney PW1000G geared turbofan is going to have on aviation in the form of improved fuel efficiency. There are apparently already plans to retrofit the Airbus A320 with this new geared turbofan engine on the A320neo. The Boeing 737 is a close competitor with the Airbus A320, and could likely also benefit from a retrofit to a geared turbofan. During some hangar chat, I heard it said that there isn't room on the 737 to fit the wider geared engine.

Are there any plans to release a 737 with a geared engine?

If not, could this put the 737 behind its competitors, especially the A320?


texts: Do fighter jets have an auxiliary power unit? If they don't, then how does the propulsion/ignition process start in the engine?


texts: Is there a maximum airspeed to deploy a ram air turbine?

texts: Is there any airspeed limit for deploying a ram air turbine? Can airspeed be determined from the rate of its propeller rotation? Could that data be used to determine altitude?


texts: Did Hamilton Sundstrand Corporation fix this GPWS problem?

texts:
So I was reading about Garuda Indonesia Flight 152 and one of the reason it crashed was for a GPWS malfunction. Here is the Wikipedia article about the crash and GPWS: Garuda Indonesia Flight 152

  The plaintiffs alleged that the GPWS was defectively designed, that the manufacturer was aware of its deficiencies in mountainous terrain for over a decade, and had the system worked as designed the accident could have been avoided.

Was this problem ever fixed? Did Hamilton Sundstrand Corporation fix the problem? Also I was wondering if anybody knows what company makes the GPWS for an Airbus A350 and an Airbus A320?


texts: Why does the Comet's horizontal stabilizer have so much dihedral?

texts:
The Comet's horizontal tail has a noticeably extreme amount of dihedral compared to that of, say, a 707:

(Image by MilborneOne at Wikimedia Commons.)

Note how the Comet's tail has about twice as much dihedral as that of the 707 in the background, especially considering the Comet's quite low wing dihedral.

Why such a large amount of dihedral on the Comet's tail?  Does this have anything to do with the Comet's tail being unswept (whereas most later jetliners have horizontal stabilizers that have almost as much sweep as the wings, if not more)?


texts: What happened to the power plants after an aircraft is retired?

texts: Few weeks ago, there was a Boeing 747 belong to an airliner retired in our country. I am not sure what series is that, but seems it is 747-200. What then will happen immediately to the power plants after it decided to be retired? Is the power plants will be reused, at least for another purpose?


texts: Do turbo prop airliners generate thrust using the propeller and compressed air or just the propeller?

texts: I looked at a picture of a q400 engine and it showed air being compressed so I was wondering if it has two systems to generate thrust.


texts: Where can I find EUROCONTROL's fuel coefficients for the B737?

texts:
I am trying to compare the fuel impact of different types of approaches, to compute the fuel flow I am using a model developped by Eurocontrol (Base of aircraft data). I am struggling to find the fuel coefficients necessary for the computation. Do you know where this data can be found ?

I am particularly interested in the B737 (-600,-700 and -800) and the A320, I have found this http://catsr.ite.gmu.edu/SYST660/B737_BADA.pdf which is exactly what I am looking for but I find the value of the second thrust specific fuel consumption coefficient (.10000E+15 kts) quite weird because it is very different from what I had read before. For example it's .14300E+04 kts for the B767-300 https://www.eurocontrol.int/sites/default/files/field_tabs/content/documents/sesar/bada-b763-opf.pdf and I trust this link since it comes from Eurocontrol's website.
Does anyone know whether this data is accurate ?


texts: Is there any emergency situation in which jet engines would not be shut down before passenger evacuation of a transport aircraft?

texts:
A comment to this answer discusses the possibility of evacuating passengers risking ingestion into the engines if evacuating over the leading edge of the wing. That particular question discusses the Boeing 737. For example:

  "I always thought that the reason to go off the back of the wing was to avoid getting sucked into an engine."

and

  "I'd imagine on a land landing, the leading edge could bring a passenger dangerously close to being ingested, should the engines be rotating.."

However, I really can't see any valid situation that calls for the following sequence of events:

Emergency landing (either on land or on water)
Keep engines running
Begin evacuation of aircraft
Shut off engines (during or after evacuation)

Instead, the sequence of events would seem to be:

Emergency landing (either on land or on water)
Shut off engines
Begin evacuation of aircraft

in which case some unlucky individual might possibly hit (come into contact with) some external or exposed part of the engine or engine pylon, but I have a really hard time seeing how anything could be ingested into the engine at that point.

For the purposes of this question, I suppose "engine running" can be interpreted as "sufficient intake airflow for large foreign object ingestion to be a concern".

Is there any valid situation where post-emergency-landing evacuation would begin while the engines are still running? If there is, then please describe at least one situation which would call for that and describe why such a course of action would be necessary in that situation as opposed to waiting for the engine front intake fans to spin down.


texts: What data did the earliest HUDs display (for fighter jets)?

texts:
Ideally I'm looking for a screenshot with a bullet list of data. I started my search at the obvious encyclopedic site and was surprised to learn that the earliest HUDs (on fighter jets) go all the way back to the 40's.

So what data did they display? Presumably it would be a limited set of data compared to today's standards, and I'm very interested in what was considered the most important data for a HUD. Especially, did they have that circular piper showing where your bullets would impact?


texts:
Normally on commercial flights, passengers are expected to bring their seats to an upright position for take off and landing. There are a few valid reasons for this.

A little while ago, on a couple flights in Upper Class on Virgin Atlantic the pre-flight announcement stated that their seats are certified for take off and landing in any state of recline.  I didn't think of it much at the time (other than, "oh, ok then"), but now thinking back I don't think I've ever encountered this on any other airline.

So my question is two-fold. First, what kind of certification was the announcement referring to? And, second, are there any other airlines that have this "feature"?

Update on response to a comment. The seat belt in that case was a standard lap belt. The seats themselves were positioned somewhat diagonally facing partially forward and were almost like bucket seats in the upright position.


texts: How much thrust is needed by an aircraft to have vertical takeoff?

texts:
In some airshows, I have seen some big aircraft (like 737) takeoff almost vertical.

Generally, fully-loaded passenger/cargo planes don't do that, I guess due to safety issues but I think there needs a lot of extra thrust to have an almost vertical takeoff.

So is a vertical takeoff possible in every kind of airplane (without excessive weight and giving full thrust) or only some specific ones can do it?


texts: Why are Leading Edge Flaps (LEFs) create lift while down at slow speeds but decrease lift while down at higher speeds?

texts:
When taking off or landing, both LEFs and trailing edge flaps (TEFs) for fighter aircraft are in the down position to provide more lift. However, when flying around at higher speeds (let's say 500-600 knots), the left LEF going down and the right LEF going up causes the aircraft to roll left.

My personal theory is that the dominant form of drag (induced) at slow speeds means that the increased camber provides more lift although slightly decreasing the angle of attack (which is good if you are close to the stall angle of the wing). However, at higher airspeeds the slight decrease in angle of attack caused by the downward LEF and also the larger parasitic drag causes the decrease in lift of the wing.

Does this theory hold up? Or is there more to it that I'm not considering?


texts: Why are prop blades not shaped like household fan blades?

texts:
My two projects right now are learning to fly and 3D modeling a replacement blade for antique fan, and a question occurred to me:

Why are airplane propeller blades not shaped like household fan blades?

They're both designed to push the same fluid with some degree of efficiency, but household fan blades look a lot more like ship screws/boat propeller blades. Is it a weight issue? A visibility issue? A drag issue, and if so, how?

EDIT - This is not a duplicate of this question because the proposed answers a question about angle of attack and pitch, which are aviation jargon words that may mean nothing to novices. Pitch and angle of attack also have little to do with the front-view shape of a household fan or prop blade, which is likely the most obvious difference between the two types of blades in the eyes of someone without an aeronautical engineering degree.


texts: Why is hybrid laminar flow control preferred for swept wings over other options?

texts:
As I understand it, a (the?) major form of laminar-to-turbulent transition on the swept wings of large jets is the crossflow caused by the sweep. One way to control this is laminar flow control by boundary layer suction.
Now, I would expect crossflow to exist over all of the wing chord. Yet, hybrid laminar flow control, the solution I see most commonly proposed for the swept wing, only has suction on the leading edge, followed by natural laminar flow behind. Supposedly this gives simplicity yet most of the benefits of full-chord laminar flow control.
Yet we know that the favorable pressure gradient introduced by natural laminar flow is destabilizing to laminar flow on wings! And that crossflow still exists at the back. So, what makes this only partial suction a good compromise? Is it because the crossflow issue is bigger at the leading edge than elsewhere?


texts: What would happen if a takeoff is not rejected following an elevator malfunction?

texts:
A few weeks ago, the University of Michigan basketball team was on a plane that was in an accident.

Link

How bad could this have been?  From my understanding the issue was here:

Is this the kind of thing that is checked before takeoff?  From my understanding they were traveling at nearly 200 mph when the pilot rejected takeoff.

EDIT:  What would have happened if the takeoff wasn't rejected?


texts: How do airports charge airlines for using their gates?

texts:
I'm wondering how the airports charge an airline for using a gate or a parking spot (if they use buses). Does the airline have to pay per time or per "event" or do the larger airlines have fixed gates for which they pay a yearly rent?

Could you elaborate on what systems there are and when they are used? How much are the costs?


texts: What makes a visual approach quicker than an ILS approach?

texts:
In the question What's the preferred approach for a passenger jet? it is mentioned that pilots prefer Visual Approaches over ILS Approaches, as they are a lot quicker.

Why would a visual approach be quicker than an ILS approach?


texts: Is there a class E corridor in the class B north of San Diego International?

texts:
I am a relatively new pilot in the Los Angeles area and I have a question related to the Class B Airspace north of San Diego International, adjacent to Torrey Pines Glider Port.  The LA Terminal Map and Fore Flight show what appears to be a corridor or brake in the Class B Airspace. It shows the B Airspace to be 18 to 100, however there appears to be an altitude box just to the left of this area with an arrow pointing to the area in question that says floor of 18 to ceiling of 32 & floor of 68 to ceiling of 100.

My interpretation of this is that this box designates a Class E corridor just above 3,200' and just below 6,800'.

I have asked a number of pilots more experienced than myself and have received conflicting answers to my interpretation. Some agree and some do not.  I have attempted to find references online, but the only reference to a corridor in San Diego is the VFR corridor that overflies San Diego International above 3,300 and below 4,700 Northwest to Southeast.

I have attached a photo of the chart from Fore Flight for the area in question.  I would appreciate if someone who has flown this area could clarify this for me I would be very grateful as I don't want to bust B Airspace. Is my interpretation of the chart correct?  If not can someone explain to me what the box is saying?   Thank You.


texts:
What floatplane is this model?

(own work)


texts: Can I legally own and fly fighter jets in the UK?

texts: I’ve seen a similar post, but it applied to America. Could I own and fly a BAE Systems Hawk T1 in the UK? What kind of regulations are there? Obviously it would have to be unweaponised but I was just wondering about the specifics.


texts: How can a pitot tube freeze when it's heated?

texts:
Reading Why turn off pitot tube heating?, it appears that the pitot tube heat can be switched off to extent its lifetime and also in case of short-circuit.

(Thales pitot-static probe, source BEA)

On airliners the probes seem to be heated during the whole flight. This makes me ask myself different but related questions:

Accidents occurred due to probes freezing. How can a heated pitot probe freeze?
Extending the life of the tube seems a questionable choice, I'd rather expect the technology to be improved and be able to sustain permanent heat. Heating a small metal device from -56°C to 5°C (or maybe more, say 100°C, taking into account comments) looks like feasible (not taking into account air friction) ⇢ The problem seems to be how to transfer enough heat from the metal (which is very hot) to the ice accretion.
A short-circuit is easily terminated by a fuse or a circuit breaker. Why does the crew have to worry about switching the heat manually, adding a possibility to have it OFF unintentionally?


texts: Are engines fed differently in reduced gravity aircraft?

texts:
Reduced gravity aircraft are basically airliners without passengers seats. As airliners, those aircraft were not designed to fly for a long time in zero-G. Specifically engines were not designed to be fed with fuel for several tenth of seconds in reduced gravity conditions. I'm aware that aerobatic aircraft are equipped with devices to feed the engine in negative-G conditions for a limited amount of time, but what about the reduced gravity aircraft?

EDIT: aerobatics aircraft are equipped with header tanks and/or flop tube able to get fuel in tank even if flying inverted (e.g. flop tube's end goes to the bottom of the tank, bottom defined in Earth frame of reference, whatever the attitude of the airplane). This design allow pipes to always be inside the liquid fuel of the fuel tank, and thus pumps can do there job (pump liquid). But when in zero G, liquid is no longer attracted toward one side of the tank (either the bottom or other side) and thus pipes may be fed with a mix of air (or whatever gas or vapor that is inside the fuel tank) and liquid fuel. Pressurized tanks do not change this. Yet, engine must be fed in fuel for several tenth of seconds in those condition, and I doubt fuel contained in pipes can last more than few seconds. Devices to fed a reduced gravity aircraft's engine should be different from the one in aerobatics in at least two way:

aerobatics are designed to operate in inverted flight (not zero-G) and are in zero-G condition for a small amount of time (less than a couple of aerobatic maneuvers before being again in normal or inverted flight)
reduced gravity aircraft are airliners (may be modified, but how?)


texts: Is the 737-800 a different plane from the 737 MAX 8?

texts: I am flying on March 16 from Barbados to Toronto on a Westjet Boeing 737-800 also referred to as an aircraft type 73H on my ticket. Is this a different plane from the Boeing 737 MAX 8, grounded by several countries?


texts: Which countries permit pilots to carry a firearm?

texts:
In the US, the FFDO programme trains and permits pilots to carry a firearm in the cockpit.

Do any other countries have a similar programme?


texts: At what distance beyond the aiming point is a landing considered a "Deep Landing"?

texts:
In Flight Data Monitoring (FDM) programmes, the Deep Landing calculation is based on difference between the aim point (or glide slope touchdown point) and the actual touchdown point.

How are the limit values for determining whether a landing qualifies as a Deep Landing specified for long or short runways?

Is there a legal distance after which a landing is qualified as "deep". Does that depend on the runway length?


texts: Can countries introduce new aviation policies unilaterally?

texts:
Let's say some country intends to introduce a new aviation policy that conflicts with ICAO regulations, like only aircraft certified and approved by our government can fly in our airspace. Can they do that unilaterally? Has it ever happened?

For instance, Russia may declare a country as enemy country and it may use its equipment (e.g reconnaissance aircraft) to spy on this enemy country. In this case enemy country may start defining its own policies and make sure that defense or civil aviation equipment/software are used in compliance with these new policies.


texts: Would a pure flying wing in straight and level flight have zero wing bending stress?

texts:
In studying the NASA 247 foot wingspan solar powered Helios aircraft it seemed that evenly spacing the weight would help create a lower bending stress across its span when in flight, as gravity and lift forces would cancel each other out more evenly as compared to a single fuselage.

The Helios did have spaced pods slung underneath, but none at the ends.  The aircraft, in turbulence (perhaps an updraft) that caused its wingtips to bend upwards, started a pitch up/pitch down cycle until the wing failed.  Could more even spacing of weight on the wing reduce the possibility of this happening again?


texts: What powers the air required for pneumatic brakes in aircraft?

texts: What powers the air required for pneumatic brakes in large airliner aircraft? Is it bled from the engines, or do they have a separate motor and pump?


texts: What are the potential threats of having the landing gear dirt from mud in a rectractable landing gear airplane?

texts: Recently I have been flying an aircraft with the landing gear very dirt with mud due to the parking area of the airfield on grass and the meteo conditions in recent days. I wonder what are the threats to have the landing gear with mud on it especially with retractable landing gear system as I had that day. Just for info I was flying a PA28R-201.


texts: Is there any engine that doesn't use a propellant to produce thrust?

texts: As far as I know, all engines used in aircraft produce thrust by means of some propellant: kerosene, hydrogen peroxide etc. Maybe I've missed something, but could you tell me, are there any engines that can produce thrust without using exhaust gases expelled from the nozzles? Is it even possible?


texts: What steps are airlines taking to retain and acquire pilots?

texts:
It's well known that there's a global commercial pilot shortage, likely due to the cost of becoming a pilot, as well as the lackluster starting salaries. I've heard that airlines are making pushes to acquire new pilots, as well as retain current ones, but what steps are they taking to accomplish this?

Please link to sources if you can.


texts: Why is it rare for small aircraft to have winglets?

texts: I've noticed that winglets are very rare on small aircraft. I wonder why this is the case. Wouldn't they have the same advantages, especially because they travel at low speed? Or is it just a wrong impression I got and they aren't that rare?


texts: Why descent below DA/DH or MDA could only be accomplished using natural vision?

texts: I'm curious why descent below DA/DH or MDA could only be accomplished in visual approach conditions? Is there any regulation to indicate that?


texts: Why nitrogen generation system is only present in centre tank only?

texts: I was going through FCOM of A320 and it mentioned that nitrogen generation system is only there for centre tank and not for wing tanks what is the reason for the same?


texts:
What is subcritical and supercritical boundary layer?
What is the difference between them?


texts: What is the operating temperarature of a scram jet at its theoretical maximum speed?

texts:
What is the operating temperature of a scram jet at its theoretical maximum speed of Mach 24?

For those with access to a simulator and do such simulators exist and are they possible?

Given this speed is achievable and there are no known existing materials that can handle the temperatures, would ceramic shielding along with liquid cooling assisted by refrigeration technology suffice and is it feasible for both the engine and air frame?


texts: Why do airlines use SIDs and STARs when flying IFR. Wouldn’t it be easier and make more sense for them to use direct routes (for example KDFW.KLAX instead of KDFW.L4D.ZIBIT.J5N.BUBIN.P3K.KLAX (not a real route, just an example)?


texts: Which airplanes require two (or more) pilot/operators?

texts:
There is a related question about when regulations require a co-pilot. This question is about which airplanes cannot be physically flown without at least two people operating it.

Are there any airplanes currently in existence with such a requirement?

This can be because there are controls or systems that must (as in fall-from-the-sky-must, not FAA-must) be controlled or monitored by people in different stations. And by "flight," I mean taking off, controlled flight, and landing (in one piece) - and not any mission specific, tactical or navigational requirement.

Related: When does a flight require a copilot?


texts: Are flexible pavements not recommended in hot climates?

texts: I've received a feedback from an airport manager that flexible pavement is not recommended for runways within the regions of an extreme hot climates; this is because of the particles of asphalt that generate through the aircraft traffic along the time over runways, in which a potential risk on aircraft engines may occur by vacuuming these particles, and that some airports, accordingly, have replaced the runways' flexible pavement with rigid one. Is that true? Is there any new recent recommendations from ICAO or FAA in this regard??


texts: Was the Cessna 208 developed to meet Fedex's requirements?

texts:
I remember hearing or reading somewhere that the Cessna Caravan was developed because Fedex had issued an RFP for a light aircraft to carry cargo on shorter routes and to unimproved airstrips. According to whatever I heard/read, that made it unique as the only mass-produced civilian aircraft to be developed based on a customer's request, at a time when manufacturers built aircraft according to their own opinion of what was needed in the market and then tried to sell them.

Is there any truth in this?


texts: How does a fuel tank fire self-extinguish in an A380?

texts:
On Qantas Flight 32 there was...

  ...an undetected fire in the left inner wing fuel tank that eventually
  self-extinguished

How does a fire in a nearly full fuel tank self-extinguish?


texts: How would modern jet fighters engage and defeat prop driven fighters?  Assuming all things being equal (avionics, weapons, etc), if the two aircraft were co-altitude in a level merge, what tactics would the jet use to quickly overwhelm his adversary?


texts:
With fly-by-wire and computers between pilot's command and flight control surfaces, it is easy to imagine the implementation of an autopilot inside the computer, but I read somewhere that autopilots existed before WW2. They were made only to maintain altitude and heading, but worked at a that time with the mechanical linked between pilot and control surfaces.

How did these old autopilots work?


texts: How does cost per seat-mile differ between commercial and private jets?

texts:
I was reading an article the other day that mentioned many smaller private jets are more efficient, faster, can climb quicker and land with less space than larger commercial aircraft. Some of the obvious metrics make sense such as shorter landing distances, but the efficiency peaked my curiosity.

I am basically asking what is the cost difference or cost per seat mile difference in say a a Boeing 737 vs a smaller often private jet, say an Embraer Legacy 600 or similar with its maximum seat capacity setup.


texts: How to calculate the forces and moments required to aerodynamically actuate slats?

texts:
I am trying to make a wing where slats automatically deploy once it hits a higher angle of attack, let's say right before stall.
I need to roughly estimate the forces and moments acting on the undeployed slat.

Here is a sample airfoil with the pressure distribution superimposed:

Source: own work

I plan to operate at a Reynolds number of 100,000 at stall speed, and the preliminary dimensions for the slat position are 10% for the width, 1.5% for the depth and 2% for the gap, all in chord percentage. Refere to the image below for the definition of the dimensions:

Source: Effect of Slot Span on Wing Performance, J.Granizo

I think the next step is to use the following equations for the slat alone:

Source: Fundamentals of Aerodynamics 6th edition

However, I only know the pressure and friction coefficients on the top surface (marked in red line). Do I assume that the entire bottom surface (marked in blue line) is at atmospheric/freestream pressure?

A point in the right direction would be appreciated.


texts: Do airlines weigh passengers and baggage before loading the aircraft?

texts: I'm aware of some aircraft that have systems to calculate weight and balance.  For those aircraft that don't have such systems, how does the pilot know they are within weight and balance limits?


texts:
I've often heard that learning to fly gliders makes you a better airplane pilot, in person and in answers here and here. Is this true, and if so, what specifically is it about gliders—or at least glider training—that makes this true?

Note: I understand that age, health and/or cost can make gliders more practical or accessible to some folks, but for the purposes of this question, assume those aren't a factor.


texts: Who controls VFR flights in class B airspace in Europe?

texts:
I was reading about this incident where a near miss occurred in class B airspace between IFR and VFR flights that were in contact with different controllers.

So I would like to know which controller normally gives the clearance to enter class B airspace to a VFR flight? When entering from class E, does the area controller provide the clearance or the approach controller of the airport whose class B it is? And is the flight then handed off to the appropriate approach controller? And when the aircraft then crosses from one class B airspace to another?

That particular incident happened

at 4000 ft amsl. This chart does not list frequency for that airspace, but it is clearly airspace of the (Danish) Kobenhavn/Kastrup (EKCH) airport. But it is in Swedish airspace and Sweden area (ESAA). The VFR flight was flying from east to west, so must have crossed from other class B sector that apparently belongs to Malmo (ESMS) about 5 nm earlier. So does it make any sense it was (still) talking to Swedish controller (the article is not absolutely clear, but seems to say it was Sweden area, not Malmo approach) while the other flight was talking to Kobenhavn approach?

Obviously I am not trying to find what happened; the investigation will hopefully eventually explain that. I'd just like to understand what the normal procedure in such situation is.


texts: Why is the IATA Airline Accounting Code abbreviated as PAX?

texts:
I'm dealing with some configuration files used in a software system. There's a single configuration file for each airline, e.g. like for Cathay, below:

"IATA": "CX"
"PAX": "160",
...

My understanding is that PAX is used to indicate a passenger count, is that understanding incorrect?

I figured out that the PAX is referring to the IATA Accounting Code for the airline:

But why is IATA calling this 'ACCOUNTING CODE(PAX)', when apparently PAX is used to refer to 'passengers'? Is it because this is specifically the accounting code for passenger transactions?


texts: In a piston aircraft engine, how much heat must be removed by the oil cooler?

texts: It is pretty straightforward to compute the heat and power generated by the combustion process, given the displacement, RPM and fuel mass flow rate. Similarly, the power exhausted can be computed with knowledge of EGT and conservation of mass.  The difference is dissipated as heat, from air cooling of cylinders and oil cooler.  I'm looking for a rough ratio between oil cooler and cylinder heat dissipation.


texts: Pilots diploma made in USA-nostrification in Europe. How it works -what are the procedures?

texts:
I am a Polish citizen and am presently enrolled in flight training in USA.
Upon graduation, I will have approximately 250 hours of flight time and the following certificates and ratings:

PRIVATE PILOT
INSTRUMENT RATING
COMMERCIAL PILOT
MULTI-ENGINE RATING

In addition I may also have the following:

CERTIFIED FLIGHT INSTRUCTOR (CFI)
CERTIFIED FLIGHT INSTRUCTOR-INSTRUMENT (CFI-I)
CERTIFIED FLIGHT INSTRUCTOR-MULTI-ENGINE (CFM)

I have been led to believe that I may not be able to work in the United States and will have to return to Europe for employment.

How much of this training and experience will be transferable to Europe?

I understand that the ratings would not allow me to immediately be
employed in Europe, but I am hoping that the level of training and experience will at least be of value and can be transferred.

Does anybody know how to nostrificate a diploma from the USA to Europe?
Please advise me as to what I may expect after I finish school in USA and back to Europe what are costs, and what is the time necessary to nostrificate- transform all papers into Europe..

Will it be possible to get a job in USA airlines for not US citizen? on F1 visa?

If not what are the procedures to transfer a diploma to Europe and what is necessary to do it .where to look for help in that case?


texts: What is the average weight difference between composite and metal airliners?

texts: Is there any rule of thumb for weight savings using composite materials. For example, is there an early model large airliner like the B747 or even B737 that later was modified with composite wings or fuselage that shows weight savings?


texts: Do FAA knowledge test endorsements have an implicit expiration date? If not, can I add one explicitly?

texts:
Many things in aviation have a 60-day window. For example, a graduation certificate from an approved part 141 course is valid for the purposes of a checkride for 60 days after the date of graduation.

Suppose I endorse an (otherwise fully qualified) student to take a private pilot knowledge test, but the student doesn't take the test for an extended period (because of illness, military deployment, or whatever).  Some amount of time later, the student appears at a testing center with the endorsement in hand.  Is there a particular time limit beyond which a knowledge test endorsement is no longer valid?

If not, could I write the endorsement so that it includes a void date?  Something like:

  I certify that Mr. Orville Wright has met the required training of blah blah and is prepared to take the private pilot knowledge exam. This endorsement is valid until October 31 2017.


texts: Where can I take my ultralight aircraft?

texts: I know many airports do not allow ultralight aircraft but can I take it to work, home, or to the bar? What is the limits of freedoms of travel in an ultralight?


texts: Which aircraft have made notable use of lateral asymmetry?

texts:
I'm asking about functional asymmetry - doors on one side but not the other wouldn't count.

Examples

I can think of three examples:

experiments with oblique wing designs, such as NASA's utterly hideous AD-1, designed apparently by Burt Rutan
displaced fuselage designs, such as the Blohm & Voss BV 141 or (another Burt Rutan aircraft), the Boomerang
all single-propeller aircraft, in which the torque of the engine exerts asymmetrical forces on the aircraft

Symmetrical asymmetry doesn't count

(Then there are some that I don't think really count - for example, the Wright brothers' Flyer 1 placed the engine and the pilot side-by-side, but since they were intended to balance each other out and the twin propellors were symmetrically placed, that counts as an attempt at symmetry as far as I am concerned!)

Other examples, and the reason for their asymmetrical design

Are there any other good examples? The more ugly and wrong-looking, the better.

I'm interested in the problems that the asymmetry aimed to solve - for example, oblique wing designs aimed to procure aerodynamic advantages (which turned out to be at the expense of handling issues), or Rutan's Boomerang which "was intended to be a multi-engine aircraft that in the event of failure of a single engine would not become dangerously difficult to control due to asymmetric thrust" (Wikipedia)

Visual reference

Just for reference, here's the AD-1 (NASA, via Wikipedia):

... and the BV 141 (Deutsche Bundesarchiv, via Wikipedia):


texts:
In flightradar24 I only see 737 MAX flying from Gol Airlines and Aeromexico, but none from AA.
Is American actually flying the 737 MAX or is FlightRadar24 reporting aircraft types wrong ?
I also see a few MAXes with a Boeing ticker flying in the Seattle area, probably delivery tests.


texts: What information am I legally required to provide during a FAA ramp check?

texts:
I was taught during my private pilot training to only provide the minimum information necessary to the FAA when they ask for something so that you don't open yourself up to more scrutiny.

In that spirit, what am I legally required to provide to an FAA inspector during a ramp check?  If they ask for something, can I tell them "No" or "I will respond to that in writing within 30 days after I have my lawyer review your question"?

In my car, I can refuse to let them look inside unless they have a search warrant.  Does the same apply with a private airplane?


texts: Could the stick position be used as a Angle of Attack indicator?

texts:
True or False: The stick determines elevator position and elevator position determines angle of attack. When the critical angle of attack is exceeded, the wing stalls. So, given a design with enough elevator authority, if the stick is in your lap, then the wing is stalled. If the stick is, say an inch farther forward, the wing will not be stalled. Let's stipulate no flaps/slats, calm air, normal CG, positive G, and plenty of elevator authority. Maybe use a plane such as the Luscombe 8A for the sake of this discussion. That will keep things straightforward.

I guess the crux of what I'm asking is: why couldn't the stick be used as an angle of attack indicator? Let's assume a pilot is able to very precisely detect the stick position, or that maybe an indicator is installed in the panel which is connected to the bottom of the stick under the cabin floor.


texts: Are there any English speaking flight schools to get a PPL in continental Europe?

texts:
I'm a UK citizen, planning on getting my PPL this year. My goal was to train intensively, taking lessons several times a week. Unfortunately the UK weather means that even if you have the time and money to train that often, it's easier said than done since lessons are called off more often than not due to a low cloud base or rain.

I was thinking I might be able to get it done faster if I went somewhere like Spain or Italy where the weather is better, but obviously for this to work I'd need to find somewhere with English instruction. I'm assuming if I could find such a place, then as long as the school was EASA certified then the hours would count towards a UK PPL and I could just return home at the end to take my checkride and written exams.

Does my plan make sense, or is there a flaw I've overlooked? If it would work, can anyone recommend a good school that meets these criteria?


texts:
When I was reading about the HAL Tejas I observed that it was described as a "tailless" plane. However I could see a tail in the picture.

After careful reading I am assuming that being tailless means not having any tail planes a.k.a horizontal stabilizers.

Does tailless means no tail at all?


texts: What are the advantages of the Riblett airfoil over the Original Pietenpol Airfoil?

texts: Some builders have opted to build a Riblett airfoil based wing for the Aircamper rather than using the original Pietenpol wing.  What are the basic characteristics of the Riblett wing which differentiate it from the original wing, and what are the pros and cons in construction and performance?


texts: Do you need a commercial certificate to fly unpaid for a non-pilot owner?

texts: Let's say that an aircraft owner is not a pilot and needs someone to fly an airplane for him. If the owner pays 100% of the costs for the flights but does not pay the pilot, does the pilot require a commercial certificate?


texts: how are UAV systems (aircraft+ground facilities) fitted with landing aid system?

texts:
For commercial aircraft, precise landing aid systems (ILS, GBAS) are required for autolanding, but these navigation systems are too expensive to be used for UAV operations. However, a lot of UAV OEMs have claimed and demoed landing the fixed wing UAV at a runway which is typically used for a Part 23 aircraft.

How do these fixed wing UAVs perform and autoland?
What kind of landing aided system are installed on the ground or on board?


texts: Why don't the magnetic compass and direction indicator spin the same direction?

texts:
You set a direction indicator (DI) based on the magnetic compass in certain GA aircraft, e.g. Cessna 172. During training you're taught how to align the DI with the compass, the DI being the opposite side to the compass. Why haven't they been designed in a way to make them visually match to make it easier to set the DI?
This illustrates what I mean:
Compass
|||330|||
 ^

DI
|||330|||
       ^


texts:
I have heard about auto-thrust yet I still don't know what it is. Can someone please explain to me what it is?

I know that I can just Google this up, but I was hoping that a community which revolves around aviation would be able to answer my question.

I did end up using Google to do some preliminary research and I found this definition:

  An autothrottle (automatic throttle) allows a pilot to control the power setting of an aircraft's engines by specifying a desired flight characteristic, rather than manually controlling the fuel flow.


texts: When might an aerodrome contain a public right of way?

texts:
My textbook on air law says the following about Rule 41 of the Rules of the Air:-

  A person shall not, without permission, go onto a part of an aerodrome provided for the use of aircraft. This applies to any part that is not a public right of way.

It seems unlikely that you would have a public right of way across the manoeuvring area or apron of an aerodrome. How common is this?


texts: Which aluminium alloy is used in the Boeing 747's fuselage?


texts: Temperature sensor are needed to compute True Airspeed for low speed aircrafts?

texts: I know standard air data computer can produce true air speed with total air pressure, static air pressure, and total air temperature. But for a low speed aircraft <100 knots, do I need to install a total air temperature sensor or other temperature sensor to get the true air speed computed? Or air temperature is not needed for low speed aircrafts and the air data computer can produce the true airspeed based on the calibrated air speed?


texts: Would it have been possible to equip the Concorde with swing-wings to help with lift at lower speeds? The delta wings on the aircraft worked well at high speeds, but it took a long time for it to achieve takeoff speed. A swing-wing would give it the aspect ratio for low speeds and delta form for the high speeds.


texts:
The manifold pressure gauge of the Japanese Ki-61 has values which go from +40 to -40. I know this has to be relative to something since negative pressure can't exist (you can't get more vacuum than a vacuum), but I'm not sure what it's relative to.

Why did the manifold pressure gauge on the Ki-61 have negative values?


texts: What is this "stick" on top of Cessna 152's wing, and how does it work?

texts:
What is this device? What is it for? Seems that some variants have only one, while some others have two.

Added: As some have two, so what are they? The answers and comments have not explained which antennae they are, especially for the ones with two antennae. As I asked, how does it work?  I need an explanation; if the two antennas are for the same purpose, then why do they need two at the same place?


texts: What are the typical max speeds & g loads at which internal weapon bay(IWB) door can be opened for weapon deployment?

texts: What are the typical numbers for popular aircraft like the F-22 & F-35 which have IWB?


texts: Can one ARTCC take over for another ARTCC in an emergency?

texts:
Earlier today the ZNY ARTCC was shut down due to COVID-19. This resulted in a temporary ground stop for incoming flights while a contingency plan was being activated. When certain sectors within an ARTCC are shut down, as happened yesterday at ZID aircraft are routed aground the sectors, but it would be very difficult to route around an entire ARTCC facility’s airspace. In fact, as ZNY was shut down, aside from the temporary ground stop, flights over the ZNY airspace appeared to continue as normal.

I make the assumption that the centers are connected and that when one center has to shut down entirely for some reason that the other ARTCC’s are capable of taking over for them and providing the same radar service. How true is this assumption?

Note: There are conflicting reports at this time as to whether the entire ARTCC had to shut down or just some sectors. The question still stands as to what would happen if an entire center had to close.


texts: What is the rationale behind placing arrestor gear on a long runway?

texts:
I'm looking at the obstacle chart and the aerodrome chart (pdf; source: Hellenic Civil Aviation Authority) for LGLM (Lemnos, Greece), which serves both military and passenger aircraft.
The runway length is 3016m (9895ft), and, according to the charts, there are also "Arrestor Barriers (nets) 75M before THR RWY 22L", as well as "Arrestor Gears (hooks) 583M, 554M beyond THRs RWY 04R and 22L respectively".
Considering that arrestor gear can have operational consequences for civil aircraft (Skybrary link), apparently its presence is operationally justified for the Hellenic Air Force.
My question is
What could be the reason that arrestor gear is placed on a fairly long runway? The fighters operating from this base are, I believe, F16s and Mirage 2000s. Would a 3-km/10k-feet runway not be enough for such an aircraft, even if we assumed braking problems?
Note: I have been on the island many times as a civil aviation passenger, and the arrestor gear is always in place, so it seems to be a (semi-)permanent installation.


texts: Why are three-bladed helicopters relatively rare?

texts:
I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four.

Factors that I'm guessing contribute -

Storage - two-bladed helicopters take up a lot less space. So you're probably going to stick with two blades until you're compelled to move to four
Simplicity - while an odd number of blades can be perfectly balanced, it may be easier to manufacture systems where the forces counter-balance in opposition rather than having to balance the entire system.
Cost - two slightly longer blades are presumably a lot less expensive to maintain / purchase than three shorter ones.

These are guesses though. My question is - is my perception correct, and if so, why?


texts:
When returning from each flight, during which it is subjected to adverse conditions, say arctic weather, desert heat or just moderate conditions, how is an aircraft evaluated to accurately keep track of its lifespan?

If the method is a standard: "this aircraft has had "this many" hours of flight, & therefore, there are "this many" hours left for the aircraft before it is rendered not worthy for service" then this method doesn't consider the various conditions the aircraft is subject to during each flight, which impacts the aircraft's lifespan at varying degrees. I trust there is a more accurate method of evaluation (after each flight perhaps?)

Appreciate your asisstance in clarifying this doubt.


texts: Is it possible to detect a pitot static failure (blockage) of air data probe during flight and alert the pilot?

texts: Loss of static and pitot tubes affect the display of airspeed, altitude, vertical speed information. Loss of this information can  be catastrophic for flight. How are the pilots communicated about the failure of these ports (ex: when they get blocked). Or is there a system in place already that detects the blockage and unblocks it. Even if such system exists, what is done to ensure that pilot does not trust the airdata information displayed during the time when the ports are blocked?


texts: What does it mean to maintain a positive g loading?

texts: When we hear about a "g", if I am not mistaken, one "g" is an equivalent force to that which is experienced when we are standing at sea level.  So what does it mean if a plane maintains a positive g loading and vice versa when a plane maintains a negative g loading along with how it feels to someone inside.


texts: Why is there an ETOPS marking on the nosewheel door?

texts:
What is the reason for painting ETOPS on the door of the nose gear?

"ETOPS" marking on a B737-800 (source)

Markings on the belly are supposed to be useful for ground handlers, what is it supposed to do here?


texts:
As far as I know, only 4 countries can build aircraft jet engines on their own:

USA {GE, P&W}
Russia {Klimov, NPO Saturn}
France {Safran}
UK {Rolls-Royce}

All other countries use jet engines bought from companies of these 4 countries.

Is that true?
Are German, Japanese, and Chinese companies not able to build aircraft jet engines on their own?
Why is building jet engines so tough for companies from other countries?


texts: How is smoke detected in the cabin when flying without passengers?

texts:
The Boeing website states that smoke detection devices are not present in the passenger cabin as the passengers/cabin crew are able to detect the smoke:

  A dedicated smoke detection system is not required in the occupied volumes of the main cabin due to the ability of passengers and the cabin crew to recognize smoke.

How would smoke be detected in the cabin when flying without passengers or cabin crew? As an example, this could be the case on a ferry flight where no one in the cabin may be present to detect smoke.


texts: How are multiple frequencies monitored at once?

texts:
In a tiny single-engine aircraft like a Cessna, all the way up to a modern jetliner like a 747, it seems the cockpits of modern aircraft have at least 4 separate airband radios, for monitoring up to 4 different frequencies at once.

However, the cockpit has only one up to (rarely) three occupants wearing headsets.

When Ground calls you and says, "monitor Tower, on 121.65", Tower wants to tell you something from that frequency, but Ground also wants you to stay on their frequency.

By which mechanism are multiple frequencies monitored by one or more (fewer than the number of radios/frequencies) crew members?

all the running cockpit radios are heard at the same time, mixed into the same audio

how to know which transmissions came from which freqs?

switches that cause exactly one of the radios to be "active" in the headsets at once, and the other ones are not heard in the headsets

how to monitor multiple freqs this way, without missing transmissions or switching back and forth so quickly it would be unreadable?

I've looked around, but I can't understand how multiple frequencies are easily monitored at once, without running into the problems I mentioned in my guesses.

So how can a pilot alone, or a pilot with a first officer, listen for their callsign on multiple frequencies at once?


texts: How does the maneuverability of the FJ-2 Fury and F-86 compare?

texts:
The North American FJ-2 Fury was the US Navy version of the F-86 Sabre jet.

I want to know if G maneuver limits were in favor of the F-86 or the FJ-2 Fury.


texts: Does one have to practice engine failures in flight training?

texts: Are engine failures practiced normally? What exactly are the reasons? Is there a particular type of failure that is required training for all pilots worldwide?


texts: Why there is no wake turbulence right after touch down or before rotation?

texts:
It is said that wake turbulence occurs when an aircraft generates lift and there is no wake turbulence after touch down or before take off. That's how we avoid wake turbulence. However, I've thought we have lift while on landing roll or take off roll because there is the angle of incidence and at least a certain amount of speed, just not enough lift to be airborne. Based on my idea, I don't really understand why does wake turbulence suddenly disappear like a magic when we land.
Can someone explain this please?


texts:
I'm about to ask a question that's already been asked but that wasn't answered. I was torn between opening a thread thats many months old or posting a new thread. I apologize if I picked the wrong option.

Previous thread: What is the IATA code for the A320neo family?

What are the IATA codes for the A320neo family?
According Lufthansa, A320neo (ICAO: A20N) is 32V. But that's all that I know.


texts: Airbus towing: is it necessary to switch on the Y HYD pump?

texts:
So, somehow our operations came up with a new requirement: if one of our A320 or A340 is being towed, we are supposed to switch on the Y ELEC pump (if the engines are off). This shall prevent inadvertent retraction of the nose gear caused by the towing force.

Is this even mechanically possible for A320/A340 airplanes? I highly doubt it...


texts: How are leaks in door rubber seals detected?

texts:
There are few reported incident where the rubber seal on the door was damaged and it took numerous hours to find the cause and then find the location of the damage. I want to know the ways to detect the leaks mostly for the big passenger jets.

I am not sure if this can be detected during maintenance checks or even aircraft is in air.


texts: Why are min and max temperatures (TN TX) not published in TAFs in the United States?

texts:
I know that other countries like Brazil, Argentina, etc. do publish minimum and maximum temperatures in their Terminal Aerodrome Forecasts, abbreviated TN and TX. But why are they not shown in TAFs in the United States? (I guess other countries in Europe also have the temperatures).

BTW, where are the expected min and max temperatures in the US published in an official report? NOAA/NWS? WX-BRIEF?


texts: Why there is no online radar coverage of Madagascar?

texts:
I noticed that no planes heading to FMMI are plotted on all the prominent online radars despite the fact that most of them are likely equipped with ADS-B.

What does it take to remedy that lack of coverage?


texts: How does the autopilot act when it receives an obviously bad temperature value?

texts:
Assuming the plane is on autopilot: for example, if a plane is flying high (over 20000 feet) and its autopilot receives a positive value of external temperature, which is clearly abnormal or impossible.

What will the autopilot do with such a obviously wrong information?


texts: What are these "winglets" on the roof of the 737?

texts: I circled the parts on the fuselage in red.


texts: Is it required to contact approach when flying VFR into a Class D airfield?

texts:
Is it required when under VFR to contact an airfield's approach when approaching to land at a class D?

KDLH is my example airfield. They possess independent radar approach and departure (same frequency) with a separate tower frequency. What would be the process of approaching this airfield under VFR?


texts: What is a Simultaneous Offset Instrument Approach (SOIA)?

texts: I have heard about Simultaneous Offset Instrument Approaches (SOIA), special procedures for runways that are spaced particularly close together. How exactly do they work? What are the requirements for an airport to be eligible for the procedure? What special requirements are there for pilots flying the approach?


texts: Why are autonomous vehicles not used at airports for on-ground services?

texts: Autonomous vehicles have been around for over an decade, other industries such as the maritime industry have already been using unmanned vehicles at ports. Curious to know why airports are reluctant to implement this despite the clear benefits it has.