texts: Has any jurisdiction mandated passenger training?

texts:
A chunk of pre-departure time for each flight is dedicated to a safety briefing for passengers that few passengers seem to pay attention to. In the aftermath of accidents, it has been revealed at least a few times that passengers did not listen to or understand the briefing, or in the panic of the moment, forgot all about it.

A couple examples:

Southwest 1380: Air masks not properly worn
BA 2276: Taking bags off during emergency evacuation

With this in mind, has any civil aviation jurisdiction ever considered or implemented mandatory passenger training for commercial flights? (In the form of a short annual/bi-annual course requiring a passing grade in order to be allowed to fly. Sort of like CPR training, but for airline emergency procedures.)

Curriculum could include:

Knowledge of oxygen mask usage
Ability to exit plane properly during emergency (closest exit, no belongings)
Emergency door operation
Wayfinding in smoke-filled cabin

I'm not advocating for this, or suggesting it would be effective, but curious if it was ever considered, especially in the 50s or 60s when air travel was still relatively new (and somewhat more dangerous).

In the context of this question, I'm asking if a regulatory agency has attempted the above, not an airline or airport operator. Regulatory authorities are the one who require the current safety briefing approach.


texts: What happen if an aircraft is more than 10 hours overdue for its 100-hour inspection?

texts:
Let's assume an aircraft for hire's 100-hour inspection is about 20 hrs past due (120 hrs since the last 100-hour inspection). Can I just say that the aircraft is not airworthy and the aircraft cannot be operated?
Or, if I'm the owner, can I operate it just for personal flights? Is this illegal?


texts: Is it possible to stall a plane so badly that the nose refuses to go down due to lack of airspeed?

texts:
So basically, a stall from a high AoA to the point that the entire plane just falls with the rear end pointing straight down?

Because if wind is no longer passing over the wings, then this includes the elevator, and the elevator can’t deflect the wind with no forward speed?


texts: Referring to a general aviation airplane, what is the throttle friction lock and what do I need it for?


texts: What is this high wing, single engine aircraft?


texts: What are the requirement for electrical grounding of aircraft in hangar storage?

texts:
When an aircraft is being stored in a hangar between flights, are there any requirements to have the aircraft connected to an earth ground?

I believe that there is (although I'm looking for the reference), and if so, why and how should this be accomplished?  Is attaching a cable to the metal structure of the hangar an accepted practice?


texts: Is the airport capacity related to number of runways?

texts:
Lets say two different airports have the same number of runways, and terminals capable of handling any number of passengers. I realise that year round climate may have an effect on the number of days that planes may be able to land. But are there any other major factors which are able to make a big difference to the number of passengers those airports would be able to process?
For example, do the placement of runways interfere with air traffic control?

If both make maximum use of their capacity, is it likely that both would have very similar numbers of annual passengers?


texts: What causes airliner tyres to burst as often as they do?

texts:
Tyres burst - not just fail - remarkably often. The Aviation Herald lists 26 tyre-related incidents this year.

I'd expect fast landings or overweight landings and heavy braking to be implicated, but often, tyres burst during the take-off roll:

Nordica CRJ9 at Kiev and Tallinn on Jun 4th 2019, burst tyre
American B738 at Kingston and Miami on May 7th 2019, tyre damage on departure
American B738 at Vancouver on Apr 19th 2019

Some other failures also appear very regularly (cabin pressurisation, flaps, landing gear). However, these are of complex systems that have many interacting parts, and they also exhibit multiple ways of failing.

Car tyres, which are maintained much less well than aircraft tyres and travel far greater distances over much harsher surfaces, very rarely burst, even when they fail.

Why do the tyres of these large aeroplanes burst rather than fail in other ways? What is it about the way that aircraft tyres are made, or the conditions that they are subjected to, that cause them to burst as often as they do?


texts: Do paper airplanes fly like normal airplanes do?

texts: After a while of researching, I found that nobody actually knows how paper airplanes work and after experimenting myself, I can't really find much about it. If anybody does, have a good answer and has a better researching angle, please tell me.


texts: Where to find information on weight breakdown for helicopters?

texts:
I would be interested in information on the weight breakdown for the different components of a helicopter. How much of the maximum gross weight is related to the airframe, engine, gearboxes, transmissions, rotor systems, avionics, etc.

Could someone point me to a data source where i can find such information?

I already found a very reliable source on technical specification of helicopters in the Type Certificate Data Sheets published on the EASA website here:
EASA TCDS List


texts: How are redundant twin engines coupled on a helicopter?

texts:
I understand that a Eurocopter EC135 can fly on only 1 engine.

In this instance, is the dead engine power turbine still coupled to the rotor? Does it freewheel? Is there a clutch to disengage it? If not, does the power turbine draw air through the dead engine?


texts: What flight simulator software did Captain Zaharie Ahmad Shah use?

texts:
During the investigation of Malaysia Airlines Flight 370, it was revealed that Captain Zaharie Ahmad Shah had a sophisticated home-built flight simulator setup.

(article source)

What flight simulator software is he using here?


texts: Will the new Boeing NMA be 'more electric' than the current B787?

texts:
I understand that the B787 is the 'most electric' aircraft to date, however there have been many issues with the plane, and I'm interested in knowing if the latest Boeing New Midsize Aircraft (NMA) - possibly the B797 - will still use the same 'more electric aircraft' architecture as a result.

Specifically, are there any details/guesses on the following:

If the electrical power generation capacity of the Boeing NMA will be lower/higher than the B787
If the Boeing NMA will 'revert' back to traditional bleed-air engine systems.
If the Boeing NMA will use more or less electric components (such as in actuation systems) than the B787.

Any help on any one of the questions would be very appreciated!


texts: Do ATC displays show the target altitude that the pilot has set in the autopilot?

texts: When cleared to climb/descend to a level, the pilot enters that level in an altitude preset window, allowing the autopilot to climb/descend and level off at that level. Is this level, preset by the pilot, visible on an ATC radar screen?


texts: Did Air Europe fly to Toronto from Lamezia Terme?

texts:
I am looking for more information regarding a flight from Lamezia Terme (SUF) to Toronto Pearson (YYZ) that according to some of the people I spoke to used to be operated by Air Europe around 1993.

I have researched wikipedia's Air Europe page and it looks like they have never even had an aircraft capable of servicing the 4,087 nm route.

Has any of you any idea of how I could retrieve more detailed information? For example, is there any way of knowing which airlines operated the route back in 1993?


texts: How precisely must ATC speed instructions be adhered to?

texts: Is there any speed tolerance in regards of ATC speed control instructions during the landing approach?


texts: Has it happened before the EASA and the FAA disagreed on the airworthiness of a plane?

texts: With the Continued Airworthiness Notification and with the updated statement https://pbs.twimg.com/media/D1fZ4GTW0Ac4Qsr.jpg in contrast with EASA   2019-0051-E it is crystal clear the EASA and the FAA disagrees on the airworthiness of the 737 MAX at this time. Had this happened before?


texts: What can pilots do to spot the onset of hypoxia?

texts:
If there is a loss of/lack of air pressure at high altitude, without an explosive decompression (for instance as on Helios 522 or N47BA) are there any signs that pilots can look out for that they might not be getting enough oxygen?

Does an audible alarm exist on any commercial jets when cabin pressure is at a dangerous level?

It's my understanding that the brain is impaired, and reaction times are increased with oxygen deprivation. Are there any techniques to combat this, after noticing hypoxia onset? e.g. slowed breathing


texts: What fail safe protections exist to prevent non-plug type cabin doors opening in flight?

texts:
Increasingly, modern types do not use plug doors to save complexity and weight.

As far as I know, the doors automatic/manual interlock only controls whether the slide inflates when the door is opened.  The doors have electrically powered locks and EICAS alerts to show unlocked doors.

However, anything electrical can and does fail.  What fail safe protections are in place to prevent non-plug doors from being opened in flight?


texts: Where can I find details on the control surfaces of the F-15C?

texts:
Me and my team were working on a short animation and I need precise details on the following if you guys can point me to a website or answer them here it'll save hours off my search cause Google isn't helping much.

The different stages of the flap extension with their degree of rotation.
The maximum degree of the ailerons going both ways
The maximum degree of rudder both ways
The maximum the elevators can go both ways

And as a big bonus can you provide me with the landing gear specs as in how long it takes to extend, retract, open the great doors and so on? Or a video of an actual F-15C retracting and extending would be great. Not one of those mini-prototypes.


texts: Why are downward pointing winglets more efficient?

texts:
While most aircraft have upward-pointing winglets

Source

there are also some UAVs (I couldn't find any manned aircraft$^1$) with downward pointing winglets.

Source

I'm pretty sure that other considerations such as ground clearance, propeller/camera system protection and stability were the determining factors in the examples showed above.

However, according to a study (p.11) referenced in this question downward-pointing winglets are more efficient.

  This also means that winglets sticking up are not as efficient as
  folding them down.

I couldn't find the sources mentioned in the paper.

What makes downward pointing winglets more efficient? What are the efficiency-related differences between the two directions?

$^1$: No, neither the A-10's nor similar wingtips count.


texts: Does an amended shortcut clearance change the clearance limit?

texts:
A typical IFR cleared route is like,

KABC VOR1 V12 VOR2 V23 VOR3 V34 VOR4 KXYZ

Suppose the verbal ATC clearance is "N7890, you are cleared to KXYZ airport, KABC.ZYBUD departure, radar vector VOR1, V12 VOR2 V23 VOR3 V34 VOR4 then direct, climb and maintain 3000, expected 5000 5 min after departure, departure frequency is 123.45, squawk 4321"

While you are en-route on V12, ATC says "cleared direct to VOR3". Does this new clearance change the clearance limit from KXYZ to VOR3? If no further clearance is issued while approaching VOR3, should we hold at VOR3 or continued with the cleared route firstly obtained?

POST EDIT:
The context is within US.


texts:
We've all heard the "acts like a cushion of air" explanation tossed casually around by CFIs.

There's also plenty of books and reference materials that give a detailed, accurate, and complete explanation of ground effect, and which are incomprehensible to most student pilots.

What's the simplest way to accurately explain ground effect?


texts: Can gliders and single-engine planes have vortices?

texts:
I read,

A third physical explanation of the source of induced drag is that the
wing tip vortices contain a certain amount of rotational kinetic energy. This
energy has to come from somewhere; indeed, it is supplied by the aircraft
propulsion system, where extra power has to be added to overcome the
extra increment in drag due to induced drag.

[Source: Introduction to Flight by John D Anderson, Sec: 5.3 "Finite Wings"]
And interpreted thus,

Vortices have rotational energy which comes from propulsion. This additional requirement of "Thrust" can be balanced with Induced drag.

And this makes me question, how gliders form vortices when it does not have engines? Or even single mounted engines in prop planes that do not have engines on wings?
Could you see the vortices created by the glide of owl in the video here and here?
Also, if the phenomena of vortex is not due to engines than why there are four vortices in this famous image:


texts:
Today, at my part 141 flight school I failed a stage check (flight test), because I did not perform a hold. I'm in com-multi training and was shooting a single engine approach in a Beechcraft Baron. I was inbound from the SSW preparing to shoot the GPS 01 approach. I knew the AUGIE route said "no pt", however, because I was a straight in approach, I believed that the hold was not required. So I started the approach at the BEJCY (IAF) rather than turning off course.

The examiner failed me right then and there. After the flight, he told me the ONLY time a hold/procedure turn is not required is where a "no pt" route is published.
Aren't there other circumstances that relieves a mandatory hold/pt?


texts:
Technically, unless a helicopter's centre of gravity and centre of lift (centre of the rotor) are in perfect alignment, it would generate a pitching moment which would make it unstable.

So, how does a helicopter manage to solve this issue. (I'm assuming it's impossible to perfectly align the CG and the centre of lift due to practical loading conditions.)


texts: At which point does an airliner start to pressurize/depressurize the cabin?

texts: Do airliners start changing cabin pressure at takeoff or after reaching a certain altitude? Also when do they start depressurizing the cabin ?


texts: Are aircraft separately certified for CAT III ops for +2500 feet elevation?

texts:
Is it mandatory have separate certification for aircraft operating CAT III Operations on airports having elevation more than 2500 feet? If so do that aircraft are to carry any additional equipment?

One of our airline operator has submitted a list of their aircraft which are certified for CAT III operations at airports above 2500 feet elevation. We are yet to be equipped with CAT III, hence we would like to know if we have to have any additional ground systems to enable all aircraft to operate CAT III.


texts: Is the taxi route omitted in low visibility (LVP)?

texts:
This video shows an auto land into Schiphol during bad weather / LVP (Low Visibility Procedures).

After reporting vacated, the ATC instruction is quite short (around 2:45). Simply the gate number. (I'm not sure if part of the conversation is omitted during editing, but nothing seems to suggest that.) This is my transcription of it:

  Pilot: Ground, hello, 4A, vacated S3

  ATC: 4A, stand D5

  Pilot: Stand D5, 4A

As you can see (read, hear), no route is given. I checked the Dutch eAIP but found nothing. The only thing I found is from a Jeppesen chart (dated 2005):

The highlight above hints at, but not explicitly, that taxi routing is not necessarily given – or so I understand it.

If more specificity than EASA is needed, then EHAM would do.

Initially I thought it's a follow-the-greens, but then at the intersection shown below both directions were illuminated:


texts: Changing the interception angle in autopilot for OBS or VOR in the G1000 from 30 to something more aggressive

texts:
I am flying the G1000 and have noticed that if I program in an OBS TO or a VOR TO (this might apply to FROM as well), the angle at which I fly relative to my programmed in bearing is 30 degrees.

For example, if I am flying 180 and want to fly to an airport nearby with an OBS setting of 250 and put this in and turn on NAV, the plane will turn to 220, which indeed will intercept 250 at some point. But if I am not far from the airport I am wanting to approach at 250, this interception will get me too close to the airport, by the time I reach 250. So I would like a more aggressive interception angle than 30... maybe 90? How would I do that?


texts: Can ailerons be used to control yaw and pitch

texts: Is it possible for an aileron to be used to control the roll, pitch and yaw of a vtol drone


texts: What is the proper procedure when a passenger seat belt becomes inoperable during flight?

texts:
I was on a Delta flight in Business class on a 777 and during flight the motor of the seat caused the seat belt buckle to pop off the end of the seat belt causing the seat belt to be inoperable.

This was a completely full flight and the flight attendants were unable to fix the seat belt.  I ended up just tying the two ends of the seat belt together for landing and the crew found that acceptable.

What should the proper procedure be in this case?


texts: What is the expected range of handheld radio?

texts: For a handheld VHF radio carried as an emergency backup, how should I expect the effective radius of a handheld radio to compare with on-board radios in two-way communications? I figure reception should be the same. But transmission would probably be different, dependent on the power. Would the difference be significant? What factors would change the useful radius of a handheld radio?


texts: Have you seen gyroscope horizon moving while flying long distances?

texts:
I've seen video where a man is telling that pilots flying in aircrafts do not see gyroscope horizon drift while flying long distances.

I know this question might sound idiotic but I'm just curious if you have ever noticed actual gyroscope horizon (mechanical one) moving while flying long distances. If not, are those gyros compensated somehow?

Have you ever recorded that on your camera?


texts: What are U-2 loiter and stall speeds at low altitude?

texts: I've read that a U-2's takeoff speed is around 115 mph (or kts?). Given those glider wings, how slow could one fly, lightly loaded, at low altitude? Say, less than 10,000 feet?


texts: Why are there so few Lancasters still flying?

texts:
According to Wikipedia there are 54 airworthy spitfires in the world (30 in the UK alone), yet there are only 2 airworthy Lancasters (Lancaster B X in Canada & Lancaster B I in the RAF's Battle of Britain Memorial Flight).

As far as I'm aware they are similar aircraft (in terms of technology, obviously different size and role) from the same era so why is there such a difference in the numbers?

Is there a fundamental issue with preserving the Lancaster or is it simply a financial/lack of interest issue?


texts: What is the maximum body weight allowed for a pilot?

texts:
What is the maximum allowed body weight for a new commercial pilot student?

Would someone weighing 130kg be rejected on the basis of health? If so, what should that person weigh to avoid the rejection?

I have read about regulations mentioning 75 kg + 10 kg for flight crews, but I doubt if all pilots fall under that category because I have seen many pilots who look heavier than that. But I need some professional advice on this regarding current commercial aviation.

I'm interested in rules in India, Canada and the USA.


texts:
Some answers on this site, such as this one, refer to something called aeroelastic deformation.

What is it and how does it affect aircraft construction? Are there any famous lessons learned on this topic as far as aircraft construction goes?


texts: Based on this fuel flow chart, why isn't it more optimum to remain at an intermediate altitude rather than climbing?

texts: I am having a bit of confusing as to why people say planes gets more efficient as they fly higher. Because on a typical long haul flight the Fuel Flow of the aircraft will obviously be much more that when it was lighter as it was heavy but my main question is since aircraft FF decrease with weight but at the same altitude isn't it more efficient to keep flying at the same altitude instead of climbing further? Here below are some charts on the B737 FF getting lesser with the altitude as it gets lighter. Notice how the FF goes up as you climb higher even though its lighter. Looking at the charts I suppose isn't it more efficient to keep flying at the same altitudes? Can anyone help me clarify this? Thanks


texts: Can ADS-B used for voice communications?

texts:
Everyone knows the radio communications doesnt sound great altough they work perfectly.

But can the brand new ADS-B communications be used for carrying audio signal? Would it be clearer?

The ADS-B will be mandatory by 2020 (At least for anyone that wants to fly at the controlled airspaces) so why dont we ditch the old radio system full of parasties and use ADS-B instead for voice communications instead?


texts: What are the best methods for calculating lift during different stages of flight?

texts:
Supposing I have the all dimensions of an RC airplane: wingspan, NACA airfoil, aspect ratio, fuselage length, etc., what would be the best methods of calculating the expected lift the aircraft should feel during takeoff, climb, and cruising stages? The conditions are assumed to be that of sea level.
I also have estimates of thrust produced by the propellers on the airplane, center of gravity location, stall speed and lift off speed


texts:
I have to admit that I’ve always kind of struggled with the Visual Descent Point (VDP) concept. Looking at the Terminal Instrument Procedures (TERPS) definition:

  “The VDP is a defined point on the final approach course of a
  non-precision straight-in approach procedure from which normal descent
  from the MDA to the runway touchdown point may be commenced, provided
  visual reference is established.”

Fine, I take that to mean that if I start down from Minimum Descent Altitude  (MDA) too far after passing the VDP then my descent won’t be “normal”. What I don’t get is when the VDP is “Not Authorized”. Take a look at the RNAV (GPS) Z RWY 24 approach for KTTN. Included in the notes is the statement: “VDP NA with Northeast Philadelphia altimeter setting”.

What does that mean? Why is the VDP not authorized now that the MDA is 60 feet higher? If I didn’t want to descend too late before, I certainly don’t want to go past the VDP when I’m 60 feet higher! Is the note just telling me I better have the required visual references in sight so I can start down BEFORE the VDP? That might not be possible if visibility is at the 1 mile minimum.

@voretaq7:

I understand the implications of altimeter setting from a different airport and how your actual altitude could be higher than indicated.

I guess I'm hung up on what it means to "use" the VDP. Assuming that you use the Dive-n-Drive technique (rather than a constant descent rate), then your statement "Fly the approach until you have the runway environment in sight and then figure out your own glide path intercept based on the visual references you have" is what you are going to do regardless of what altimeter setting you use. In that case, what does it mean to "use" the VDP? In a light piston aircraft with airspeed under control, I may prefer to wait until the VDP and make a steeper than normal descent even if my actual altitude if higher than indicated. That way, in poor visibility, I avoid obstacles that may exist below the MDA prior to the VDP. So exactly what is the FAA saying I'm not authorized to do while using the PNE altimeter setting?


texts: It's a movie/TV trope that people can talk to each other and even whisper on commercial airliners in flight.  In a story, it’s pracical to confront the reality of the experience and have characters have to deal with the noise when flying.  But, how does a private jet compare?  Will an intern flying with the big boss for the first time find it refreshingly better, or even worse, or what?


texts: Is King Khalid International Airport in Riyadh actually very big?

texts:
Apologies in advance if this is in the wrong place, there isn't a geography StackExchange so this was the next best option I could find.

I've read multiple things about the huge size of King Khalid Internaional Airport (IATA: RUH, ICAO: OERK) in Riyadh, one source said it was bigger than Paris and others have said it's larger than the entire country of Bahrain.

Judging from Google Maps, it really isn't particularly big. What's the deal with that?


texts: Can I fly internationally as a commercial pilot, without an ATP certificate?

texts: Are commercial pilots allowed to fly internationally? Are Commercial Pilots required to take an Airline Transport Pilot (ATP) program/training to fly internationally? And is a commercial pilot the same as an airline pilot?


texts: Where did the US 'N' registration letter come from?

texts:
Why is the first letter in US registration numbers 'N'? Other countries seem to use a letter significant to their country, for instance 'G' for Great Britain, 'F' for France, 'D' for Germany (presumably for Deutschland), and 'JA' for Japan.

Does 'N' have any significance at all?


texts:
What is the VOR (VHF Omnidirectional Range) reference signal?
I have to calculate the spectrum of this signal.


texts: Who is the woman that famously survived a light-plane crash in the arctic in the 1950s?

texts:
As a kid I read a book by a woman who crashed in the Canadian arctic and, along with the pilot, walked their way out of the bush. She lost some toes (and fingers?) to frostbite, but was otherwise OK.

I believe the action took place in the 1950s, but it might have been the very early 1960s. I seem to recall it being in the Yukon, and it was a light plane, not something like a DC-3.

She was a major celebrity for a while; I recall her getting a mail that was addressed simply "to that girl that crashed in the arctic".

Does anyone recall who this was?


texts: Are there areas to avoid while flying formation with a larger aircraft?

texts:
Consider a fighter jet flying formation with an airliner-size aircraft, such as during an interception or mid-air refueling.

Are there areas which should be avoided by the fighter jet? I.e. are there certain positions where the downdraft or turbulence caused by the larger aircraft would send the small aircraft out of control?


texts: How should I answer this question about measuring airspeed using dynamic pressure?

texts:
I have come across a question in the PPL Principle of Flight material which I can't understand how to answer:

  Give your opinion on the statement "Measuring dynamic pressure is the
  way to determine the indicated airspeed of an aircraft".


texts: Comparing the Lilienthal and Wright gliders, which one had a better glide ratio?

texts:
Where can I find reliable figures about the best glides of Lilienthal and the Wright Brothers (1902 - 1903)?

From the sources below it would appear that Lilienthal's most advanced glider was far superior to that built by the Wright brothers in 1902 as the German apparatus was able to fly 1148 ft while the machine made by the Wrights only 600 ft.

It seems like the wind tunnel tests done by the Wright brothers in 1901-1902 to find optimal wings did not lead to improvements in lowering the glide angle and so increasing the flight distance.

1)"Finally Lilienthal become so skilled that he could make his glides in air velocities of 33 feet per second ... Lilienthal carried out more than 1,000 glides and attained distances of 1,148 ft. at a gliding angle of 4 degree from the hill."

Source: John H. D. Blanke, "Pioneers in Gliding", Popular Aviation, pag. 74 - 77, May 1928

2) "World Record Holders
The improved performance of the 1902 glider finally enabled the Wright brothers to gain extensive practice in the air. During September and October, they made between 700 and 1,000 glides. Flights of 500 feet were common, and a few topped 600 feet. Orville enthusiastically wrote home of their success, “we now hold all records!”"

Source: Inventing a Flying Machine

I'm asking about which glider that had better glide ratio because the Lift/Drag ratio is essential: the higher it is the longer the glide and the less powerful and lighter an engine is needed to make the glider fly horizontally.


texts:
I have this metar, I cannot find anywhere what does 0650// or 1600// or 0250// mean. I tested on multiple decoder websites. They call it unknown identifier.

ESCF 240220Z AUTO 00000KT 0800 0650// R01/P2000N R19/1900U BR OVC035/// 00/00 Q1005

ESCF 240250Z AUTO 10001KT 4100 1600// BR OVC033/// 01/01 Q1005

ESCF 240120Z AUTO 00000KT 0450 0250// BR OVC037/// 00/00 Q1005


texts: Why is Saturday a typical slow day for airlines? Not weekends, but Saturdays?

texts: Why are Saturdays typically slower days for airlines? I have always heard that they are but never a reason why.


texts: Why is runway friction measured at 65 km/h and 95 km/h?

texts: Why do we measure at 65km/h and 95km/h when we do a Runway Friction Measurement? Are there differences?


texts: Can a large aspect ratio wing be actively controlled using distributed electric propulsion to avoid getting ripped apart in wind shear?

texts:
This question is related to the recent possibility of solar aircraft becoming flyable. Solar Impulse, the NASA Helios, and the Titan Aerospace/Ascenta Aerospace solar drones have all have issues with making robust structures that can maintain station through atmospheric wind shear. So far, the best approach has been to wait out bad weather before attempting a flight.

My question is this, could the structure be actively controlled using distributed electric propulsion to smooth out the unsteady loads? Where if a section of the wing gets hit with high speed air, the rest of the motors on the wing spin faster to accelerate the flow over the other parts of the wing?

The reasons I can think of this not being doable now are the slow response time for spooling up the motors. And this means getting away with accelerating the bare minimum of air over the wing (basically only the boundary layer). Has this been done yet and shown in flight?


texts: During emergencies pilots are authorised to dump fuel, but is there any way or method to recover the fuel that has been jettisoned?


texts: What are the FAA regulations on operating UAVs in class E airspace above FL600?

texts:
What are the regulations on flying UAVs (commercial or experimental) above FL600, i.e. in class E airspace above class A? I want to make a HAPS (High Altitude Pseudo Satellite) and operate it in the higher altitudes.

Is there a way to do this without a pilot's license (I don't know if I can pass TSA background checks)? How high do I have to fly to be above class A and in the class E airspace? Would you recommend launching from international waters? And how high should I fly to be in space or in completely unregulated and uncontrolled airspace?


texts: What damage can occur and what penalties will you face for flying a quad rotor into a restricted airspace?

texts:
I live near the Cleveland International Airport. I have a Quadrocopter and the fence doesn't seem to be very high. I could probably fly my quadcopter into the airport. Is this legal? Can I crash a plane with it? Is this a new terrorist attack vector? Will the airport security try to jam radio signals or something?

This is just a hypothetical question. I do not intend to wreak havoc and crash planes.


texts: What is the disadvantage of twin-engine fighter jets?

texts:
Some air forces in the world do not use twin-engine jets at all. For instance, Pakistan. Even though Pakistan could import twin-engine jets from China at a very cheap price, they never did that.
What is the basic disadvantage of twin-engine fighter jets over single-engine ones?
Do they cost more because of maintenance?


texts: Is it true pilots in a smaller aircraft have the option of using the right or left door as rudder, to offset the actual rudder if failed?

texts: So if the rudder fails or gets stuck in the “left” position a pilot could open the right door and it would essentially counter the effect?


texts: Do helicopters have automatic tail rotor compensation for anti-spin?

texts: Helicopter pilots need to push on the pedals constantly to compensate for the main rotor torque, so that the helicopter does not start an unintended spin. But it would be annoying to indefinetly put pressure on the pedal. Do helicopters  have an autopilot that automatically keeps them stable ?


texts: How does ATC control / separate Airbus Industrie test flights?

texts:
Airbus is testing a A321 (D-AVXA, flight AIB97XA) around Toulouse this morning. The test is at low altitude, with many speed and altitude changes, including touch and go (maybe rolling slowly on the runway):

Source: FlightRadar24.

This path crosses other commercial routes / VFR aircraft, and it seems unlikely altitude, speed or even position can be anticipated all the time, but could be determined only while in flight.

All these constraints surely mean a specific treatment from ATC. How does ATC control and coordinate this flight with other aircraft? Toulouse Blagnac (LFBO) is open to commercial flights, and this test flight was within or close to Toulouse TMA.


texts: How to recognise the Tupolev Tu-154, Tu-204, and Tu-334?

texts:
Tupolev used to be the one of the largest airliner manufacturer comparable to Boeing and Airbus. However since the dissolution of USSR, its airliner business is declining, and only operated by a few ex-USSR or communist countries' airway. Currently narrowbody Tu154, Tu204 and regional Jet Tu-334 are still active.

How to recognise Tu154, Tu204 and Tu-334, compared to their rivals with similar size?


texts: I know that F=fighter, A=attack, F/A=fighter/attack, B=bomber. I can not find any information on what YF stands for. This type of aircraft is usually an experimental aircraft, but why do modern aircraft use X instead of YF?


texts: Does FAA have any info on army air corps pilots during wwII (know the FAA was formed later)?

texts: Did the FAA (or its precursors) have any relationship to Army Air Corps pilots during WW2?  If so, how would I request information on my deceased father.  Most of his military records did not survive the fire in St. Louis.


texts: Why is a TFR issued when barometric pressure exceeds 31.00 InHg?

texts: Why does a barometric pressure above 31.00 InHg trigger a TFR?


texts: Can thrust reversers be set to automatically activate on touchdown?

texts: Is there a switch on the instrument panel that will set the thrust reversers to activate on touchdown like the autobrake? Or is using the thrust levers the only way to activate them?


texts: How could I measure frontal area based on a technical drawing?

texts: I want to compare frontal surface areas of two airplanes, and I have their digital technical drawings and wingspan data. What program could I use to obtain the surface area using this data? Esentially a program that would let me put the drawing in a rectangle and measure the ratio of uncovered area of the rectangle to area covered by the drawing would be perfect.


texts: The principle in 'Trompe' is applied to airplanes?

texts:
'Trompe' (see Wikipedia) is a water-powered air compressor, commonly used before the advent of the electric-powered compressor. A trompe is somewhat like an airlift pump working in reverse, used to provide compressed air for bloomery furnaces in Catalonia and USA. By sending a fast water flow through a duct, a pull effect on air is obtained.
I wonder if a pure Turborreactor working inside a larger Duct, with no Low Pressure Fan, would have same efficiency, with less parts, as a high Bypass Ratio Turbofan. Operation inside duct, or even inside fuselage, would result in reduction of sound and thermal prints. Salut +


texts: What is the maximum number of waypoints one can have in a flight plan?

texts: Is there any constraint on how many waypoints may be in a flight plan (any regulation), including pilot defined waypoints?


texts: When flying a glider in emergency situation, would it be more safe to bailout or to land in a forest?

texts: Is there any consensus when it comes to this question? If it depends then it depends on what exactly? I'm interested in the decision making in this kind of situation.


texts:
I have been speaking to a couple of local flying schools. Originally, I was going to train on a Piper Tomahawk to obtain an LAPL. But after explaining to one of them my goals, (just flying for fun, no career aspirations) they suggested an NPPL would be more appropriate.

They explained that it would cost about half the amount (in money and time) to obtain and that their Ikarus C72s are safer, easier and more fun to fly anyway.

I am on board with all of this but I think I would like the freedom to fly in IMC in the future, they said I can add an instrument rating to an NPPL and that I can convert to an LAPL in the future if I want to anyway, is this the case? I have looked on the CAA website, but it's all a bit confusing right now.


texts: How many minutes between jetway (air bridge) detachment and take-off?

texts: Is there a standard policy / guideline that dictates how many minutes a jetway or air bridge must be detached from a commercial aircraft before take-off?


texts: What has happened to make me experience negative G with the control stick FULL AFT near the top of a loop?

texts:
I experienced negative G with the control stick FULL AFT near the top of a loop.

My questions:

Aerodynamically, what happened? Was the wing meeting the air at a negative-lift angle-of-attack (creating a skyward lift force) at this instant?
How can I change my technique to prevent this?


texts: Has the "Foote takeoff" technique really existed, and how did it work?

texts:
Reading The Crash Detectives: Investigating the World's Most Mysterious Air Disasters by Christine Negron, I came across the following description, in relation to some early de Havilland Comet accidents, notably G-ALYZ at Rome (Oct 26, 1952):

  Pilots were instructed to nurse the plane off the ground by raising,
  lowering, and then slightly raising the nose again at takeoff speed, a
  technique called the "Foote takeoff"

I was quite puzzled by this.

Has such a technique really existed? "Foote takeoff" returned
literally two search results, one pointing to the book mentioned
above, the other to another book on the Comets.
What exactly is the point/purpose of "raising, lowering, and then slightly raising" the
    nose? Why not simply rotating at VR?


texts: What does a helicopter "gas prod" gauge measure?

texts: The beginning scenes of the movie "San Andreas" partly take place in a rescue helicopter. One of the panel gauges read "GAS PROD" above it. I googled it but didn't find much. Can someone explain what it does, and how it measures what's it measures? Thanks!


texts: How does the PTT button on the radio work?

texts: I've always seen a button either built into the yoke or attached to the yoke with velcro on older aircraft. However, the other day my instructor used an older-looking headset that had a push to talk button built into the side of the headphones. He had no cable plugged in except the mic/headphone jacks and never touched the yoke's PTT button to transmit. My question is: how is the PTT function activated? Is this done with a load resistor or something that loads down the mic line, triggering radio transmission? I've done some research and looked at various manuals of audio panels and navcoms and haven't found an answer. The audio panel in use in this case is the Garmin GMA-430 audio panel, pictured here:


texts: Are Cargo Holds Pressurized, Non-pressurized, or vacuumed?

texts: I watched an episode of Air Crash Investigation, which depicts a plane catching fire due to it shipping many expired oxygen generators for planes. The narrator says that a fire in the cargo hold is very unlikely, as the cargo hold is vacuumed, to prevent fire; but however in this situation, the oxygen generators were actually generating oxygen so the vacuum was futile. I also know they carry pets in the cargo hold. So are the cargo holds pressurized, non-pressurized, or vacuumed? Or does it depend on the carrier, or aircraft?


texts: Why are some legs of a SID considered transitions, even when there's only one?

texts:
For example, consider the BAYPO8 departure from Tampa (KTPA). The CAMJO waypoint is the final waypoint on a rather linear route that does not contain other final waypoints. The second page of the FAA plate says that CAMJO is a transition.

But if you look at the ENDED8 departure (also from Tampa), there is no such designation on the LACEN waypoint. Although, coincidentally, it was considered a transition in previous AIRAC cycles.


texts: If the intake of a running jet engine is blocked for some short duration what would be the sequence of events following it? Will it cause any damage to the engine parts?


texts: How do I calculate the landing distance in a landing chart with tailwind?

texts:
With the following chart I can calculate the landing distance with the headwind, gross weight and altitude. The charts uses headwind component, but how can I calculate the landing distance required if an aircraft is landing with tailwind? There is this rule of 50% for headwind and 150% for tailwind but how do i apply this with this chart?

Thanks in advance


texts: Why does the Zapata Flyboard Air UL consume so much more fuel/hr than the Mosquito Air?

texts:
They are both ultralight and abide by FAA ultralight reg 14 CFR part 103.  The Mosquito Air is an ultralight 1 person helicopter whereas the Zapata Air UL is a micro jet turbine powered 1 person ultralight hoverboard. They weigh the same and both only carry 5 gallons of fuel as this is dictated by part 103.

The 5 gallons will last 1 hour of cruise flight time on the Mosquito while only 8 minutes on the Zapata.  Granted we are dealing with different technologies here and different fuels (Zapata uses kerosene, Mosquito uses avgas) I was surprised by the fuel burn difference.

The bare physics tells us that equal masses should require the same amount of thrust, thus energy, to hover in place where lift equals weight.  Kerosene has similar energy density to avgas.  And, a jet turbine is supposed to be much more efficient than a 2-stroke, 2 cylinder gasoline engine.

The Mosquito boasts of a 64hp engine "with the highest power to weight ratio on the market today".  The Zapata company seems not so much concerned with the gas guzzling fuel consumption.  The 2 companies seem to have different priorities here, so I'm guessing the fuel efficiency of the Zapata could be improved.  Still, this is a huge difference that is difficult to understand.


texts: Procedure turn/hold required on this approach?

texts:
I am an instrument student nearing my checkride. I recently flew the VOR-A approach into KLOL as a practice approach, using ROBUD as the IAF. I was wondering if the charted hold at MOBOH is required by this procedure?

I had a few thoughts:

It seems like AIM 5-4-9 (a) would say yes, since there is no "PT NA" on the plate. Flying a real IFR flight in this case, it seems likely that ATC would clear for a straight-in approach, in which case the hold would not be necessary.
If I was flying this approach on a real IFR flight and didn't hear "cleared for the straight in approach", I would ask ATC to clarify.

HOWEVER, I'm curious if, in the absence of specifically being cleared for a straight in approach, I would be expected to fly a circuit in the holding pattern on this approach starting from ROBUD, even though I'm already inbound on the final approach course?


texts: What is the purpose of the air inlets on an A320neo's pylon (LEAP-1A)? Passive cooling, air bleed like in the 707, or something else?


texts: What's the difference between orientation and position?

texts:
In INS (Inertial navigation system) sensors, is there a distinction between the following?

Orientation (heading, pitch and roll)
Position (latitude, longitude and altitude)

Is the orientation relative to a specific axis while the position is absolute? If yes, what is the axis?


texts: What is this very isolated, modern aviation/heliport in Northwest Antelope Valley, California?

texts:
There's a modern facility at 118 53' 16" 34 9' 28" or about 9 miles north of Neenach, California. It has 5 hangars - 1 very large, 1 medium, 3 small - with other large buildings and a large water tank (a million gallons?). It sits in the foothills of the south side of the Tehachapi Mountains. The only land access is a meager dirt road, almost a 2 track.

Any suggestions as to what it is?


texts: Is landing the 'wrong way' possible on an aircraft carrier?

texts: I wonder if the arresting wires would work the 'other' way?


texts: Do multi-engine jets need all engines with equal age to reduce asymmetry in thrust and fuel consumption arising out of deterioration?

texts: Let's assume, one of the engines on a twin-jet needs replacement and the jet is is fitted with an old engine and a newer engine after the due replacement, the older engine would tend to produce less thrust at higher fuel consumption due to deterioration on account of aging compared to the new one. Though the aircraft are designed to handle such asymmetries and modern FBW FCS should be able to handle it without bothering the pilot for any manual corrections, logically it makes sense to think one would like to do some basic engine matching to make sure the asymmetry is as small as possible. Do they follow this in real life? Are there guidelines in MRO procedures specified (both Civil and Military Jets) on how to choose a replacement engine, so as to maintain symmetry in the thrust profile?


texts: What are the differences between hand and hold luggage screening?

texts:
I have googled a little about the type of security screening done to hold and hand luggage.  From what I have seen the hold luggage is clearly subject to more rigorous screening, including tomography should it raise suspicion.

However, in light of the recent announcement for passengers to travel with charged mobile devices and be able to switch them on, I have become slightly confused as to why an explosive device would not cause an issue in the hold (I presume passengers won't be asked to remove all electrical items from their hold luggage and switch it on!).

Is the feeling that a small explosive device could do more damage in the main cabin, whereas in the hold the aeroplane's structure would absorb it?  Or is there really a "foolproof" way for the hold luggage scanners to detect whatever is being searched for ?


texts: Is line training (pay to fly) allowed in the USA?

texts:
In Europe some commercial airlines--such as Wizz Air and Air Berlin--charge licensed co-pilots to sit in the cockpit.

It is called "pay to fly" or "Line training".

Is it allowed in the USA ? Is there a FAA regulation regarding that?


texts: Is there any plan to create GPS approaches to water areas for seaplanes?

texts: Is anyone working on differential GPS approaches for seaplanes? They are a largely ignored resource with great capabilities for certain remote places


texts: In what cases does it make sense to buy a plane before you begin pilot training?

texts:
I'm halfway through a 10-year plan to pay for pilot training and buy my own plane (or a share of one).  When I was introduced to flying by a friend, he said if he had the chance to do it over again, he would have saved up and bought a plane before he started instruction.

The benefits he mentioned:

Learn in the plane you'll be flying.
Avoid "throwing away" rent money.

What I've seen in most cases, though, is that most people get their license before getting a plane.

Thus my question: when does it make sense to buy a plane before training for your PPL?


texts: What does a blue light by the toilet sign mean?

texts:
When I was flying with Swiss Air we hit some turbulence. Of course, the seat belt light came on but above the bathroom sign, a blue light came on.

(Source)

Then after a while a second one came on. I'm just wondering if this has something to do with the turbulence or not.It was an Airbus A340 if that helps any.


texts: Why do some companies perform their freight flights only during the night?

texts: I heard that for example FedEx among others performs the majority of their flights during the night, the same goes for TNT. Is the reason for that is that during the day all of the freight is being collected and then loaded for delivery in the evening? Or is there another reason?


texts: What are the consequences of pumping the throttle in an carburetor piston engine airplane during start?

texts: I have seen an expert commercial pilot pumping the throttle during start for a Cessna 152 and ever since I thought that was ok to do so, but recently studying for ATPL I read about that these technique can produce a risk of engine fire during start. What are the consequences of such a start on short or long term on the engine?


texts: Are there any ILS approaches in Class E airspace?

texts:
When descending on an ILS you can descend to 100' above the TDZE if you have the approach lighting system in sight. Cody Johnson wrote an article explaining how one pilot mis-interpreted what the rules allowed him to do, descended below 100' when there were obstructions in the way and crashed into a hill. (https://iflyamerica.org/misunderstanging_part91.asp )

Section 91.129(e)(3), Operations in Class D Airspace, is also extremely applicable in this accident. It says, 'An airplane approaching to land on a runway served by a visual approach slope indicator shall maintain an altitude at or above the glide slope until a lower altitude is necessary for safe landing.'

Class C and B incorporate Section 91.129(e)(3) by reference, so the rule applies in that airspace as well. It doesn’t specifically apply to operations at airports in Class E airspace.

My question is are there any ILS approaches in Class E airspace? Is there a a rule that prohibits them, or conversely, only allows them when there is a tower?


texts: How can I get the velocity-power curve for a particular aircraft?

texts:
The answer for How does wind affect the airspeed that I should fly for maximum range in an airplane? refers to a velocity/power-required curve.

As far as I can tell, this curve can't be deduced from information in the flight manual.

I suppose one could experiment and determine what power setting is required in order to maintain level flight at a bunch of airspeeds (or for a glider, record the sink rate, which is proportional to the negative of the power-required, at a bunch of airspeeds). Would that be accurate enough? Are these curves available from the manufacturer?


texts: How can I calculate the thrust of a fan given the diameter of the blade?

texts:
How do I calculate the thrust of a multicopter fan blade from its diameter?

I am searching for a multicopter blade that can provide a thrust of 15 - 20N.

Being someone who doesn't have any experience in avionics, I searched online for such blade believing that I could find the thrust the blade can provide, but every website for a multicopter wing, only the diameter is provided.

Is there a formula that provides thrust of a blade from its diameter?


texts: What are the advantages of squawking 7700?

texts:
I was reading this question about how do pilots send distress signals in emergency scenarios, and that got me thinking...

In voretaq7's answer, he states that there are three ways to send distress signals, one of them is by the aircraft's transponder

  Three transponder codes are reserved for unusual/emergency situations:
   - 7700 for general emergencies.
   - 7600 for loss of communication    (radio failure).
   -  7500 for hijacking or other unlawful    interference.

I can understand the reason to squawk both 7500 and 7600 in the appropriate situation, but I'm failing to understand why squawk 7700 in an emergency scenario.

So that's what I'm thinking:

In case of a hijack, the ability to squawk 7500 to silent alert the ATC of the situation, without the hijacker knowing, is an advantage.
In case of a radio failure, where you can't alert the ATC over the radio, the ability to squawk 7600 and make them aware of your situation, is an advantage.
In case of emergency, where the pilots are trying to handle a lot of things (high workload scenario), to stop everything to configure the aircraft's transponder, when they are communicating with the ATC by radio, doesn't seem like a good thing to do.

So, finally, here are my questions:

Is it common for pilots to squawk 7700 in emergency scenarios?
What are the advantages, for the pilots, to squawk 7700 in emergencies situations?


texts: Why is the Departure leg of the traffic pattern being mistaught as Upwind?

texts: I hear a LOT of newer pilots and CFI's erroneously referring to the Departure leg of the traffic pattern as the Upwind. Ref. A.I.M. Sec 4-3-2.  Actually had a Tower controller tell me "I'll call your turn from Upwind"  I was clearly on Departure...just left the runway on runway heading. I called back "1234x is on Departure, sir" No reaction. Thank you.


texts: Mathematical function in performance diagrams

texts:
I have taken upon myself to digitise some scanned old performance diagrams, e.g. roll distance as function of mass and OAT, TAS as function of power setting, etc. The obvious goal is to allow the computations to be performed in a computer instead of on paper (that is: almost never). I have written some tools to do measurements of the line intersections in the documents, so consider that problem solved.
However, what are the best functions to fit to the measured
coordinates? In selected cases, a straight line would be valid, but most often not. After all, the functions are typically solution to differential equations…
What functions are reasonable to adapt to the measured data?
Simple polynomial have the advantage that all measurements are used to fit one set of parameters. However, they are also well-known to produce oscillations between measured points. On the other hand, interpolating cubic polynomials have less oscillation problems but are… interpolating, so the measurement errors are not smoothed out. Furthermore, I have estimates of the measurement uncertainty of each point, so I would like to use that for fitting a global function.
Ideally, I would like a closed-formula for each type of curve, but I know that might be a tall order. My goal is to automate the computations, so the required precision is in the order of what you would produce with a pen and a ruler.
So, what do you suggest I do? My background is in computing science, but the physics behind these curves is beyond me. Any suggestions will be appreciated.
As an example I attach the "roll distance as a function of OAT, mass, and wind" for our PA-28-161. The image shows the actual document from our POH. I apologise for the Swedish labels, but this is in fact our legal document. The left panel shows OAT and pressure altitude, middle panel is take off mass, and rightmost panel shows wind.
Thanks


texts: What is the usage ratio of the An-225 Mriya?

texts:
Does anyone have data on how much time the An-225 (only one was produced; it is currently the largest aircraft in the world) spends flying/on missions and how much it waits for customers?

This is a very unique aircraft within the scope of contemporary aviation:

Also, there is a copy of the plane - partially built.  Does that suggest there might be need for the completion of second aircraft, to meet demand?


texts: Do dispatchers ever update and re-send a flight plan to an aircraft in flight?

texts: In what scenarios would the dispatcher recalculate the flight plan and send it to the pilot via ACARS after take-off?


texts: How much is thickness of air layer with zero velocity at wing surface?

texts:
How thick is the layer of air that is not moving(zero velocity) at the surface of wing, and can this be taller than the relative roughness height?
Because everything that is inside this layer (V=0) will not contribute to skin friction drag, intuitively speaking..
Am I right?
Or maybe  layer (V=0) is infinitely small?


texts: Who legally owns the Flight Data Recorder?

texts:
Who legally owns the Flight Data Recorder after an aircrash?  Who is responsible for retrieving it and/or allowed to retrieve it?

And how is it decided who carries out the crash investigation?


texts: Why B-52 was not re-engined as a more efficient 4-engine?

texts:
Why B-52 was not re-engined as a more efficient (also for maintenance) 4-engine but is still an 8-engine aircraft?

In history, almost all others models were re-engined with new engines also quite different from original, some examples could be C5 Galaxy or also B737 that in latest geneations requires also to extend undercarriage or make bottom "flat" area of engines, to accomodate new bigger ones.

So why B-52 remains the original projects despite its long history? Did development cost be affordable in this very long period?


texts: Why does Turkish airlines still fly over Iraq, is it safe?

texts:
I realized that Turkish Airlines have a lot of flights over Iraq. For example, here is a flight from Istanbul to Maldives (TK 730).

Do you know if it is safe to fly there? Till today I thought that flight space over Iraq was closed for commercial flights.


texts: Does the F-16 have a movable inlet? Everything else like the f15 has it does the f16?


texts: After passing a checkride, can I get the plastic certificate card by visiting the nearest FSDO?

texts: As you know, it takes more than 30 days for the plastic certificate card to be delivered. I know that right after passing check-ride, the temporary certificate is given but I need a plastic card to convert US pilot license to my country license. My government does not accept the temporary paper certificate. Is there any way to get a plastic certificate card from the nearest FSDO as fast as possible?


texts: What is the pilot's obligation to verify a registration has not expired?

texts: Old registrations had no expiration date, so a pilot could get in a plane that is owned by someone else and verify the airworthiness and registration by inspecting the documents. But that registration might be expired, and without going to the FAA site to verify it is active could find themselves flying an unregistered aircraft. Has the FAA addressed this situation since they started expiring registrations that didn't originally expire? What would the pilot's liability be in this situation?


texts:
I saw a few videos of the Sukhoi Su-35 doing some amazing aerobatics and I was wondering if a civilian could ever fly one - either for aerobatics or just fly it as their personal jet.

Obviously assume adequate training, fitness, budget, time etc. I assume you'll have to start on a jet trainer first, after you had already flown other smaller aircraft - but this is outside the scope of my question.

There is a question that suggests civilians can buy military aircraft, but it doesn't explicitly say whether they can actually fly them. One comment seems to suggest they can't, although it's not very clear.


texts:
With hydraulic control surfaces, at high airspeeds, there is a point where aerodynamic loads exceed the capability of the actuators. This limits control authority and can result in the control surface not being in the position commanded by the pilot.

Jackscrews are commonly used for horizontal stabilizer control. I know they can jam and be difficult to move under high loads, but can they be blown back from their set position or do they stay put?


texts: Where can I find data on past forecasts of planned aircraft production?

texts:
Does anyone know of a database which would list the expected production rates for various aircraft, at the time those aircraft started production?

Finding actual production to date is easy, but I would be interested in what was the original planned production. I am not interested in current forecasts, I am interested in past forecasts that have been made before or at the start of production for the particular aircraft.

E.g. Cessna 152 was assumed by the manufacturer to be sold at the volume of XX aircraft per year, when the production plan was put into place.


texts: Other than a handful of airlines, do any small operators take PPLs and pay to train them to commercial?

texts: Are there operators out there who take SEL private pilots and train them to commercial?  Do small operators like banner tow, agriculture, skydiving do that at all?  Is it way too presumptuous to ask?  To specify, I'm particularly interested in the US, especially California.


texts:
The Rotax 912 engine has dry sump forced lubrication system. They say rotating the prop in the correct way (counter-clockwise when looking from the prop side) will get the oil from the bottom of the crankcase to the oil tank.

Questions:

How does this "force back by blow-by gases" work? Is it air which gets through the carburetors and cylinders to do the crankcase what pushes the oil from the engine? If oil gets from the bottom of the crankcase to the top part of the oil tank, where the "burping" sound emerges then? In the oil line, or at the bottom of the crankcase?
If the oil gets pushed by air, why is it bad to rotate the prop in the opposite direction? Air would get to the bottom of the crankcase and air would get to the oil input line and "burp" at the bottom of the oil tank. But if engine then runs in correct direction again, won't the oil be sucked from the bottom of the oil tank again? My only guess is it won't due to the air in the oil pump which would just spin without sucking any oil...


texts:
Should DUAL flight be logged as SINGLE PILOT TIME?
Should total SINGLE PILOT TIME + total MULTI PILOT TIME = TOTAL TIME?
In what cases SELF could be specified in PIC NAME on DUAL flight?

EASA regulations applied! (Hungary)

Many thanks


texts: How much is air mass flow rate of bleed air used for environmental control system in civil aircraft?

texts: I'm looking for a general use-case formula or reference that I can use to calculate the total mass flow rate of bleed air use in the environmental control system of any aircraft. I'm not looking for information on a specific aircraft - simply a general reference that can applies to all civil aircraft.


texts: How many zig-zag patterns are there in a dog tooth leading edge?

texts:
And also what is the difference between saw tooth and dog tooth leading edge?
Like is there any difference in the number of "zig-zag" patterns on the wing?


texts: Why five touchdown zone markings for only one aiming point?

texts:
RWY 24 at Paris-Orly is a runway sustaining precision approaches. There is an aiming point and five touchdown zone markings.

Orly RWY 24, source: Google Maps

Aiming the visual aiming point, or following the ILS/PAPI glideslope should bring the aircraft on the runway before the aiming point.

Why five touchdown zone markings, in particular the three after the aiming point?

Related, but not duplicates:

What are runway Aiming Point markers used for?
What determines the touchdown zone and aiming point markings on a runway?

From the answer: "Touchdown zone marking" doesn't refer to a marking that would indicate a touchdown zone, which would imply multiple touchdown zones. Instead it refers to all markings in the single touchdown zone, including the aiming point markings.


texts: Could you help me identify a sound that began before pushback?

texts:
A couple of weeks ago I flew with SAS on one of its B737 (I believe -600 or -700). A few minutes before pushback and engine start, a rather annoying, high-pitch sound began - imagine a whining electric motor. At first I thought it was the sound related to closing the cargo door and I expected it to stop after a few seconds. It didn't, and then I began wondering whether it was something related to the APU. The sound remained the same even after engine start - and indeed for the remaining of the flight, though the engine sound somewhat covered it (or at least I got used to it, I don't know).

A uniformed pilot was also in the passenger cabin and he didn't seem at all perturbed, so I assume the sound wasn't anything out of the ordinary. And yet, I've been traveling for decades and I can't recall ever hearing this before.

Any ideas what it could be?


texts: Is it legal to board a plane dressed like a flight crew member if you are not a crew member?

texts:
Just out of curiosity: Are flight crew suits reserved to certain persons or can just be worn freely, provided one doesn't use company logos or other protected brand markings. If the country does matter, then in UK.

(Picture source)

Are the insignia like golden stripes or cap regulated by a public authority? Now questions of security may also be invoked by the Captain, or dictated by airline's rules, but that's not my main point, though explanations are welcome.


texts: Are transponders required for hot-air balloons in the US when operating within a Mode C Veil?

texts: I've taken some people flying recently for fun, and they noticed some hot-air balloons and asked me if they had transponders. In San Diego (Southern California) I often see hot air balloons well within the Mode C Veil (a 30 NM radius circle surrounding from a Class B airport). Do hot-air balloons need transponders when they are within the Mode C Veil?


texts: Where do Russian and Chinese airliner manufacturers test their airliners?

texts:
Airbus test their plane on Toulouse Airport, and Boeing test on Boeing field.

How about Russian airliners Ilyushin & Tupolev and Chinese Airliners Comac ?


texts: What is the farthest commercial flight on a B737-800 currently?

texts: Can anybody name the airline, distance and respective city pair of the farthest (not necessarily longest) nonstop flight on a Boeing B737-800 (currently or in the past)? I'm not interested in empty delivery or ferry flights, but in revenue, commercial flights with this aircraft type.


texts: Is there a minimum distance that a pilot is required to fly?

texts: Say there are two airports in a city, a large one with a control tower, and a small uncontrolled airport. Say they're only a couple miles apart, such that the small airport is well within the larger airport's controlled airspace. Is anything stopping a pilot from flying directly from one to the other?


texts: Why don't the contrails show the curvature of the Earth?

texts:
When we see contrails in the sky, let's say traveling left/right in your vision, you are seeing across a sky that is easily a couple of hundred miles wide. I mean, we can see one side of space and then another, so we can see across a great distance in the sky depending on the height of an object.  Am I wrong?  I mean, we can see entire cities from a long distance away on the ground, so an unobstructed view of the sky would give us the ability to see something very long, right?

That being said, an airplane is following a curve, and when a plane makes a trail it is essentially tracing out the shape of the earth. Being that this trail is very high up, and following the curve, why don't the trails curve (left/right trail), and we see a giant arch across the sky?  None of the lines in the sky look curved from any direction, they are straight lines, or at least appear to be.

Am I missing something?  Maybe it's a dumb question, but I remain ignorant on the topic because I haven't been able to find the answer from anyone with a clue.  This site seems legit, so I asked it here.  Thanks, in advance.


texts: Could older airplanes be retrofitted with engines with chevrons?

texts:
The 787 uses a variety of sound reducing mechanism including engines with characteristic chevrons:

(Source wikimedia commons)

Would it be possible for older airplanes to also have this type of quieter engine retrofitted? I'm assuming the engines would have to be recertified of course. But do the chevrons implicate a particular type of wing or airframe that requires them to be designed in from the beginning?


texts: Regardless of any legal regulations, is there a standard technique for designing the ground turning radius of an aircraft, or is that typically just a fallout parameter?


texts: Why does the Harrier jet have four landing gears?

texts:
I was looking at pictures of Harrier jets and I noticed something.

They have four landing gears. That seems pretty unusual for a fighter jet - most have only 3 in a triangle formation.

What is the reason for this 4 point configuration? It seems to just add complexity and cost without really increasing stability.


texts: What factors contributed to enable Rickenbacher to be found?

texts:
In Rickenbacher's autobiography he tells of his flight across the Atlantic in a B-17 after WWII. They ended up running out of gas as I recall, making a water landing in the middle of the ocean. They were stranded for about a month before being rescued.

In the early post-WWII era, how was it that they were able to find him at all? What factors contributed?


texts: What are the pros and cons of a lift fan versus a helicopter?

texts:
F-35 uses lift fan which can create 20,000 lbs (9 tonnes) of lift in a small compact platform. I can see three or four of such lift fans that could lift a heavier plane and is seems better than a helicopter because it can travel at higher speeds.

So what are the pros and cons of each design?
Which one is more efficient in lifting, lift fan or rotate wing?


texts: What will happen to a modern high bypass engine at 80 000 feet with cruise speed of 0.8 Mach?

texts: While keeping the typical cruise speed of 0.8 Mach, will the engine shut down due to "air starvation" at such high altitude? Is it possible to design a turbofan engine, which is able to provide thrust, similar to typical engines at lower altitude, with this given speed of 0.8 Mach?


texts: Do I use true or magnetic north in headwind component calculations?

texts:
For the landing performance calculations, I want to calculate the headwind component. I can do this with the runway heading and the reported wind direction and speed. But do I need to make any adjustments for true vs. magnetic north?

Is the reported wind direction towards true or magnetic north? Is the runway heading towards true or magnetic north?


texts: How will the lack of ground stations affect navigation?

texts:
VOR's and NDB beacons are getting closed day by day and they were used for making and then referencing the holding patterns and the entry procedures and how they were named.

So

How will we make holding patterns and entries from now on? What will be base them from now and how will we name them?
Will the GPS approaches replace other approaches? (Which will make GPS mandatory at least for Class B airspace I Guess)
If GPS approaches doesnt replace them... Will the old names be kept for holding patterns and entries? Will we still say RW29 VOR approach and missed entry procedures?


texts: What is the origin of the term "Tyro" for inexperienced pilots?

texts:
Over the years I have been aware of the term "Tyro" to mean a new or inexperienced pilot. I'm pretty sure it is/was used more in a military setting than a GA one, but none the less I was interested to know if anyone knows the origin of this term, and the reason why it is used? Is it still used commonly?

This may be a term only used in the RAF, I don't know.


texts: What considerations should be taken into account for landing on gravel airstrips?

texts: For the pilot of a Cessna or Piper 4 seater, what techniques and other considerations should be given before operating on a gravel/dirt airstrip?


texts: What is the use of this jet aircraft with tanks between biplane wings?

texts:
Looking at this soviet-like aircraft:

Source

It looks like a turbine engineer team met a biplane aerodynamicist team to create this strange aircraft! More over, it appears the two big pottery pieces are actually tanks.

What is the story and the use of this jet aircraft?


texts: Would it be possible to build a "rocket" using a series of ducted fans?

texts:
I'm wondering if it would be possible to build ducted fan "rocket".

My idea is to construct the duct from 18650 batteries, and to have a series of contra rotating fans along its length.

I can 3d print new blades to have a steeper angles as the air-flow/speed increases.

This is the fan I'm looking at.

A 90mm fan will let you make a ring of 16 batteries around the curcumference and it would be 6 batteries tall as it's a 6s motor.

Is this feasable/will it work? what kind of thrust would I get?

Here is a quick render I made:


texts: Are general relationships between MTOW and OEW valid for novel configurations?

texts:
I am a student in mechanical engineering with a passion for aerospace engineering, especially airplane design.

However, coming from a more mechanical than pure aeronautical background, I feel that even now, doing a masters in what is essentially conceptual airplane design, I am lacking a certain foundation in the methodology of airplane design.

To remedy this I have recently obtained the very well-known books on airplane design by Roskam and Raymer and have started working through these books.

My question is: In the modern age of airplane design, where we are starting to get interested in more novel and radical configurations, are the approaches presented by Roskam and Raymer (and I am sure there are others authors) still valid?

To summarise this design methodology I am talking about:

  Determine payload weight
  Guess aircraft maximum takeoff weight
  Estimate fuel fractions for different mission segments from historical correlations
  Calculate tentative empty weight
  Determine allowable empty weight by taking advantage of the fact that, historically, there is a logarithmically linear relationship between maximum takeoff weight and empty weight
  Compare tentative empty weight and allowable empty weight, if the values are too different, guess a new value for maximum takeoff weight and continue this iterative process until convergence

This design procedure uses historical correlations in the fuel fraction determination and through the historical trend in relationships between MTOW and OEW.

Is this approach still valid for novel configurations?

Most importantly, is it known whether this logarithmically linear relationship between MTOW and OEW independent on configuration?


texts: How does the Space Shuttle slow down during re-entry, descent, and landing?

texts:
Yesterday, my little brother asked me to help him build his new Space Shuttle Lego set.

When we finally finished building it, he started to play with his new toy and asked me to be the "Mission Control". After some time playing, he told me that he had to re-entry and land, so I gave him "permission to re-entry". Then he started to play as if he was coming back to Earth and told me that the Space Shuttle was too hot and moving too fast to land. And that got me thinking:

How does the Space Shuttle reduce speed during the re-entry process?
Does the Space Shuttle have flaps, spoilers and reverse thrust capabilities?
Can the Space Shuttle make a go-around?
Where does it land?

I know that when it is on the ground the Space Shuttle can deploy parachutes to reduce speed.


texts: What is the difference between saturated and unsaturated adiabatic lapse rate?

texts:
I'm having trouble understanding the difference between saturated and unsaturated adiabatic lapse rate.

I know the unsaturated adiabatic lapse rate is approximately 5.4 degrees per 1,000 feet in which a "dry" parcel of air cools at that rate. What does the unsaturated adiabatic lapse rate depend on? Why is the unsaturated adiabatic lapse rate lower than the saturated lapse rate?

I searched and found that the unsaturated adiabatic lapse rate is lower due to the air parcel releasing its latent heat, which causes the air parcel to cool slower, but I don't get it. When a "dry" parcel of air is cooling adiabatically, are we assuming 0% moisture?


texts: Is there any comprehensive source for landing fee information?

texts:
Is there any comprehensive source for landing fee information for US airports?

Airnav and the facility directory do not have landing fee information.

Also, going to airport web sites often is useless. For example, Massport lists landing fees for Hanscom on their web site, but do not list their fees for Logan.

Note that landing fees can be complicated. For example, there can be "landing fees" and "ramp fees" and others. So, usually the fee information is for a bunch of different stuff.


texts: Could a flight ever be considered to be operating under Visual Flight Rules and Instrument Flight Rules at the same time?

texts:
In the US, could a flight ever be considered to be operating under Visual Flight Rules and Instrument Flight Rules at the same time?

If not, where in the FARs is this spelled out?

Consider the specific case of an IFR-rated pilot flying an IFR-equipped aircraft, but with no IFR or VFR flight plan filed and no IFR clearance requested or delivered, staying in Class G airspace and observing the VFR cloud clearance and visibility requirements spelled out in FAR 91.155.  How can we determine whether this flight is operating under VFR or IFR?  Why could it not be considered to be operating under both?

Bonus question-- is there any specific case, falling within the general conditions described above, where it would matter whether the flight were operating under VFR or IFR?  Assuming that the pilot intends to, and is able to, remain in Class G airspace and observe the VFR cloud clearance and visibility requirements spelled out in FAR 91.155, would it be practical for the pilot to decide in advance that he will simply flip a coin to determine the answer if ATC, or anyone else, enquires whether he is operating under VFR or IFR?  With the added proviso that if no one makes such an enquiry, he will leave the coin unflipped until after landing, at which point he will flip the coin to see whether the flight was conducted under VFR or IFR?  Would such a plan present any practical difficulties?

Related, but not the same--

Can an IFR clearance be issued and flown through IMC in class G airspace? -- note that several of the answers, as well as many comments, to this question also address a different question (which probably ought to be asked as a separate ASE question), which is "May an IFR-rated pilot flying an IFR-rated aircraft in Class G airspace violate the VFR cloud clearance requirements without an IFR clearance?"


texts: Is flying at 14,000 MSL safe for children without supplemental oxygen?

texts:
FAR 91.211(a) requires supplemental oxygen for all passengers above 15,000 feet.  Are there any health implications of a 5 hour flight at around 14,000 feet on children without any supplemental oxygen?  Obviously the flight crew would be wearing supplemental oxygen as required by the FAA above 12,500 feet.

I've read that babies under 3 months do not have mature enough lungs for altitude stress, so for the sake of this question, let's assume the children are over 6 months with no existing health conditions to worry about.

My question is for a non-pressurized general aviation aircraft.


texts:
Is there an equation which allow us to perfectly match a helix propeller and an engine? I'm looking for an equation that allow me to correctly dimension an helix propeller for my engine. I mean that allow me to maximize efficiency and thrust, calculate the optimal number of blades, the optimal number of rpm, and the maximum rpm of my helix propeller given a certain engine power, etc.

Should I ask this question on the physics division of this website?


texts: How can a SID's MEA be above its top altitude?

texts:
The SID below has a Top Altitude of 5000 feet, but its Minimum Enroute Altitude (MEA) is above 5000 feet. Why?

I am referring to the SID depicted below, from FAA's SID charts (plate and departure route description). As one can see, the Top Altitude is 5000 for this particular SID. Nevertheless, if we take a look at the MEAs of its transition route, we notice values much greater than 5000 feet (8000, 11000 and 15000 feet).

Could someone explain to me the reason behind this?


texts: Why are electric shavers specifically permitted under FAR §91.21

texts:
This struck me as a bit strange, 91.21 which covers electronic devices that can be used during IFR flight has some exceptions, one through three make logical sense (not really sure why portable voice recorders are in there though) but number 4, Electric Shavers, is specifically permitted by the regulation. Are that many people shaving under IFR conditions that this needed to be permitted? Is there some historical or practical reason why electric shavers are specifically named in this regulation?

  § 91.21 Portable electronic devices.

  (a) Except as provided in paragraph (b) of this section, no person may
  operate, nor may any operator or pilot in command of an aircraft allow
  the operation of, any portable electronic device on any of the
  following U.S.-registered civil aircraft:

  (1)Aircraft operated by a holder of an air carrier operating
  certificate or an operating certificate; or

  (2) Any other aircraft while it is operated under IFR.

  (b)Paragraph (a) of this section does not apply to -

  (1) Portable voice recorders;

  (2) Hearing aids;

  (3) Heart pacemakers;

  (4) Electric shavers; or

  (5) Any other portable electronic device that the operator of the
  aircraft has determined will not cause interference with the
  navigation or communication system of the aircraft on which it is to
  be used.


texts:
How do rate gyros and other sensors send information to the flight control computer in an F-16? I mean is it a hardwired communication or it is done through a bus? If by bus, what is the bus called?

I have read some articles about A-Mux. Is it the bus that the gyros transmit data through? I have the same question about the actuators. How does the flight control computer send information to the actuators? By bus or hard-wired? If you have references, that will be appreciated.


texts: Why do sailplanes have such large tails?

texts:
Since a sailplane is focused on performance - what with tricky laminar flow airfoils and all.
Eo why this

Instead of this

It looks to me like that long tail is needed to balance the cockpit. Buy then why not just put the wings beside the cockpit?
Even if we cannot use a flying wing, why not s least a shortened tail? Why this weight and drag penalty?


texts: Does sex occur in aircraft cockpits, and is this safe?

texts:
I've always heard euphemisms about pilots having sex with flight attendants or passengers while flying, but I'm wondering, does this ever happen on commercial flights or in general aviation?

Have there been incidents of sex in the cockpit when the participants got caught or their actions lead to something more disastrous (like a crash) wherein the truth about their actions was clearly exposed?


texts: During a turn, will slip necessarily lead to altitude lost?

texts:
During aircraft turns, will slip necessarily lead to altitude lost?
During aircraft turns, will skid necessarily lead to altitude gain?


texts: How to calculate the shear force, and the bending and torsion moments on a wing?

texts:
I want to calculate the loads (shear force, bending and torsion moments). Assuming I have the force distribution along all the surfaces of the aircraft, my starting point is to consider the wing (and other surfaces whose loads I want to calculate) to behave like a cantilever. So, I've got these formulas:

$$
S_z =
\int_z^{b/2}
F
\;dy
$$

$$
M =
\int_z^{b/2}
S_z
\;dy
$$

Where

Sz = shear force in point z;
Mz = Bending Moment in point z;
F = Lift Distribution;
b = Wingspan;

and the coordinate system is as follows:

Are these formulas correct, and how can I calculate the torsion moment?


texts: How are aviation regulations treated on a global stage?

texts:
I know that the two large aviation regulatory authorities are the FAA and EASA, but every country also has its own civil aviation authority.

Focusing on airliners that need to operate all over the world, are they designed to meet FAA and EASA requirements only or are they subject to the regulations of every country in which they operate's regulatory authority?

Also, where does ICAO come into the picture?


texts: What is the relationship between power and fuel efficiency?

texts: We were having a discussion in our ground school that power will make the plane ascend or descend and that you use the stick for speed, forward for higher speed and back for slower speed. So does that mean as you fly higher, that means you increase power and ascend, and then fly from point A to point B, you will burn more fuel compared to if you went from point A to point B at reduced power, hence lower altitude?


texts: Can this helicopter/wrecking ball combo remain airborne?

texts:
I just ran into this meta-answer which includes this image:

My initial guess is that the wrecking ball is far too heavy for the helicopter to lift, but I'd be interested in the numbers to see just by how much.

From this silhouette, can the make/model of helicopter be determined?  (I'm hoping this image is based of some real-life craft)
If so, presumably the vehicle length is known, and the diameter of the wrecking ball may be calculated (spikes may be ignored) according to the scale of this image
Assume the wrecking ball is solid mild steel with a density of 7.85 g/cm³.  The mass of the wrecking ball can then be calculated
If the make/model is known, then presumably the max payload weight is also known, and we can see if staying aloft is a possibility or not.

Close-voters: I asked this question on Aviation.SE because the key piece of information I was missing was the identification of the craft in the cartoon image.  I think aircraft-identification is on-topic here.


texts: What are the advantages of a Spinning Wing (Magnus Effect) and why haven't any been commercially produced?

texts: What were the advantages and why was it never produced?


texts: What is the speed of gas in the core of a jet engine?

texts:
Coming from a slightly related question, I want to know what is the speed of the gas in the core of a jet engine, after combustion but before the first turbine stage.
I'll just pick a random example: Rolls Royce Trent XWB.
Also, I don't know if the speed in the core is equal to the speed at the exhaust. I just want to be clear that it's the core air speed I'm interested in here.
I realize core air speed might vary with thrust and flight level. In that case I think the most sensible thing to do is choose some typical flight conditions during cruise.


texts: Why is it appropriate to announce ‘stable’ on final approach?

texts:
I have recently discovered that a budget airlines flight deck in the UK (Airbus 320) announce ‘Stable’ on the final approach. Both the Captain and F.O, just after 500 ft is called out by the computer.

It does seem obvious and yes, the word does speak for itself, but why does it need to be verbally announced?

Is it similar to the same reason when ‘Thrust set’ is announced? To acknowledge that they are happy with the appropriate aircraft instruments and performance, and that it is ‘stable’ and safe to land? I know ‘hundred above’ is a great way to warn the crew that minimum is coming very soon so does stable lead them into this ‘is the aircraft able to proceed’? If one was to not agree that it was ‘stable’, not quite sure what that means at this stage, it does not leave them much room for negotiation does it? Aside from the obvious, what could make one pilot disagree with ‘stable’?


texts: I'm writing a sci-fi story involving aircraft and space craft. I'm struggling to get the terminology right for referring to a pilot being 'in the field' either on a mission or a training exercise. I have a feeling there is a phrase for this but I'm struggling to think of it.


texts: What is the effect of moving a propeller closer to a wing?

texts:
Does it improve efficiency?

What if the wing is just a plate? Certainly increasing plate thickness will decrease efficiency.


texts: Why does the Dassault Falcon 7X's cockpit have ashtrays?

texts:
While looking at the first implementation of Fly-By-Wire systems, I see that the 7X was the first business jet with fly-by-wire controls.
Looking at the Wikipedia page for the aircraft, I saw this photo of the cockpit and noticed the ashtray in front of the sidestick on either side:

Why would there be an ashtray in the cockpit?
The Telegraph states that they are still present in aircraft toilets due to a FAA regulation that requires an ashtray be present in the event that a cigarette is lit and needs to be extinguished. However this doesn't cover the flight deck, surely the FAA doesn't assume a pilot will light-up during flight?


texts: Do seaplane have designated landing areas?

texts: Do seaplanes have to land in particular places or are they allowed to land pretty much anywhere there is room to land safely?


texts: Can a person with a tibia problem become an air traffic controller?

texts: I have a healing tibia. In the worst possible case, if it does not heal fully, will this impede a future attempt to become an air traffic controller?


texts:
second year aeronautical engineering student here. I'm doing some aerodynamics coursework but have run into a problem.

I've read through the answers to the question "what is profile drag?" but nowhere either there or elsewhere online can I find how to calculate the profile drag. I can get the skin friction drag from boundary layer calculations, but have no idea where to go from there. So does anybody know how to calculate the form drag for a given aerofoil (eg NACA4412)?


texts: What are mechanical requirements for flying over water?

texts: What are the mechanical requirements to fly over a large water body? Are multiple engines required? Do the engine/s need to be a certain kind (turbofan, turboprop, piston)?


texts:
I get confused sometimes because I hear different theories of how propellers generate thrust.

One is that the propeller pushes air back to provide thrust.
Another is the blades generate lift creating a high pressure behind the blade pushing the aircraft forward.

Is it just one of these true or is it both? For you guys its the same way of generating thrust, but to me its two ways thats my confusion. And why does a propeller need to generate lift if it just accelerates air backwards to provide thrust. That question is my main confusion.


texts: Why all the taxiway construction at PHL?

texts:
Perusing Google Earth around Philadelphia, I noticed some new taxiway construction at PHL/KPHL.  The "time machine" feature of GE shows this to be new (latest imagery data is May 2016)--the paved areas in the red circle below don't appear in past aerial imagery.

What are all these paved areas for?  Are they extending 10R/27L?

From Google Earth

Note:  The Google Maps image for this area shows an older aerial image (without all that extra concrete).


texts: Has a life raft ever been successfully deployed in case of an accident?

texts:
Has a life rift ever been successfully deployed in the event of an air accident?

By successfully I mean removed from the aircraft, placed on the water, inflated and used by passengers/crew as a life raft.


texts: What is the difference between ground effect for an infinite wing and for a finite wing?

texts:
A question about ground effect  has just reappeared.

I think one needs to differentiate between ground effect for a finite wing (3D flow) and ground effect for an infinite wing (2D flow).

What are the differences?

That wingspan is used as a measure of distance to the ground to indicate the presence or strength of ground effect leaves me with the impression that there is a 3D aspect to ground effect. Ignoring maneuvering a long wing for the moment.

I haven't fully grasped the importance or unimportance of the trailing vortices yet.


texts:
Is it the operator, manufacturer or the NAA?

I'm going to assume the operator does the creation and amending and only the NAA is to approve the document?


texts: What are outer marker horizontal dimensions at 3 degrees ILS path?

texts:
What is the outer marker "distance" along the flight path of a 3 degree ILS?

I provide my two approaches below, but as they contradict each other, I am asking this question to learn the proper answer.

Approach #1: Wikipedia says OM horizontal dimensions is an ellpsoid of 2400 x 4200 ft (I assume the former is the dimension parallel to aircraft's path ) at 1000 ft. I assume vertically OM signal is of conical shape, therefore its horizontal size expands and should be (proportionally) larger at higher altitudes. At 3 degree glideslope, altitude range for OM crossing is between 1200 and 2100 ft (4 NM and 7 NM respectively). This gives an answer to my question equal to a range between 2400 * 1.2 = 2880 and 2400 * 2.1 = 5040 ft.

Approach #2: Flying at 100 kts, I can hear OM for ca. 12 seconds at 4.4 DME. This translates to 2000 ft of OM length at height of 1500 ft. Empiria does not give a range, but still contradicts wikipedia and is much more reasonable number, as I cannot remember hearing OM for almost half a minute while flying over...


texts: What is the range of an air traffic control tower's radio transmission?

texts: What is the maximum distance the voice messages sent by the tower on a radio channel can be received by an aircraft?


texts: When a large commercial jet touches down, is it committed to stopping?

texts: I was reading about flight RWAF9268 earlier today when a questions popped into mind.  When a large commercial jet touches down, is it required to try and come to a complete stop?  Or is it allowed to take off again if part of the craft fails (like the braking system, for example)?  And what factors would make a pilot decide to stay one the ground, or just abort the landing?


texts: Is there a maximum airfield elevation in which a Cessna 172P can operate?

texts: The title says it all: is there a maximum airfield elevation in which a Cessna 172P can operate? Or a maximum density altitude at which take off shouldn't be considered?


texts: Is there a good way to find out or estimate the prices of certain engines?

texts: I'm specifically looking for the price of a PW150 (5070bhp, Turboprop) and some 55kN Turbofan engine. I'm doing some Direct Operating Cost analysis but I have no idea how much these components should cost.


texts: What is the differance between gliding for maximum range and gliding for maximum endurance?

texts:
Is there a difference between gliding for maximum range vs. endurance?

Is the glide speed the same for max. endurance and max. range?


texts: What parts of Austrian airspace are not covered by primary radars?

texts:
I'm writing a story about the pilot of the Austrian Air Force, who uses his Eurofighter Typhoon aircraft for unintended purposes. In scope of another question we figured out that by turning off the transponder the pilot could make the aircraft invisible for the cooperative surveillance.

However, the primary radars detect a flying object regardless of whether it responds or not. This means that if a pilot of a Eurofighter turns off the transponder, civilian ATCs wouldn't see his plane, but he would remain visible for the military ones.

I assume that there are "blind spots", i. e. areas where primary radars can't detect aircraft. I believe this to be true because if primary radars covered 100 % of the airspace, the location of the Malaysia Airlines Flight 370 would be known.

Where exactly are these blind spots (if any) in Austria (areas in which primary radars of the Austrian Air Force would not detect flying objects) ?

I'm looking for a map like this for Austria:

Source of the image


texts: Is "Flight Idle" for a jet engine a constant N1% value or does it vary with Altitude, and OAT?


texts: Does the AIM really require anti-collision lights to be used during the day?

texts:
AIM 4-3-23. Use of Aircraft Lights
  a. Aircraft position lights are required to be lighted on aircraft operated on the surface and in flight from sunset to sunrise. In addition, aircraft equipped with an anti-collision light system are required to operate that light system during all types of operations (day and night).

Doesn't this imply that anti-collision lights are required to be on during the day? This is obviously not the practice?


texts: How come some aircraft have really cool registration numbers?

texts:
I've seen registration numbers like

D-ICEY - A Cessna Citation owned by a German company that produces frozen foods
G-FILM - An Alouette II helicopter used in some movies and TV series for the flying sequences

and Aviation Humor, for example, lists many other examples like TF-MOM, TF-DAD, TF-SON, TF-KID (all of former WOW Air).

I imagined it might work similar to how license plates for cars are issued in Germany (I know it's different in other countries): Here the first one to three letters are determined by the town/area you live in (e.g. F for Frankfurt). The remaining part is more or less random but you can pick from a list of these random numbers (for a fee of around 20 €).

Does it work the same with aircraft registration numbers and those people simply were lucky because e.g. D-ICEY was still available?


texts: Do any propellers/propfans use stator vanes? Why is this not a commonplace feature?

texts:
I understand that axial-flow turbine engines generally include stator vanes behind every(?) compressor and turbine stage. This makes quite intuitively sense, because without them the rotating blades would mostly swirl the air around through the engine, which would not only prevent the stages from properly transporting/compressing/expanding the air in axial direction, but also put useless rotational kinetic energy into that air. The latter is presumably also the reason why turbofans have such guide vanes behind the fan, too.

All of this applies just as well to unducted fans/propellers. Yet I've never seen stator blades behind an open propeller. There are contra-rotating coaxial propellers of course, the idea of which seems to be similar: get rid of the useless solenoidal air motion. But actively contra-rotating both props adds a lot of complexity, and seems somewhat unnecessary if the goal is mostly to remove large part of the swirling motion. Cancelling all torque is not necessary for a plane.

Especially, I would think stators could also be shaped to help retrieve some energy from the tip vortices like a duct does, without however interfering with the inflow that seems to be the reason why ducts make props inefficient at low speed.