texts: What are accurate flight simulation models called? Is there a standard model?

texts:
I'm risking a question that might be "opinion based", but I hope it will not be seen as that.

This question is touched upon in the following questions:

What are the differences between PC and professional simulators?

Is this opinion on personal computer flight simulators too strict or is it actually true?

What are the limitations of the aerodynamics modelling used in flight simulators?

However, they fail to answer what I'm asking here, even if some particular things are discussed, such as stating that the coefficients are a mixture of CFD, wind tunnel data and flight test data, or that gust loads can be modeled with Markov matrices. However, no flight model package or system is named that I could see.

For racing simulators, or car simulators, simulators that are accurate are sometimes referred to as Milliken & Pacejka or "Pacejka-like", depending on the particular implementation. This appears to be a reference model that many simulators are compared against. I'm not a tyre simulator expert, so forgive me if I just said something that is stupid.

What about flight simulation? The flight model part of the simulator, is there a "gold standard", that is typically used with most respectable simulators?

Flight simulator games often talk about the "flight model" and describe it as accurate. While I can easily imagine that this flight model is based on some simplification of Navier-stokes,

I have software background myself, and although I didn't write a flight simulator myself yet, I understand the need to simplify, and that no simulation will ever be 100% accurate. All models will inherently have various trade-offs and make some sort of sacrifices. However, that doesn't mean there isn't a relatively accepted way of performing such simulation.

I'm not asking for an opinion based answer, "this model is the best". I'm certainly not asking for a list of "the best" flight simulators. I'm curious what underlying flight model is used -- that said, I wouldn't mind one or two examples of "this famous model described in the following academic paper, is used in flight simulator X and Y".

Basically, I'm simply curious if, in the industry, a typical model or small set (a couple) of models are considered either the actual "gold standard" or more of a de facto standard.

If there is no such thing, that pretty much every flight simulator does it differently, then I'll accept that as an answer. If there is a small set of terms that everyone in the industry is familiar with, I'd love to know then. It would let me easily search up papers that describe these systems.

I'll also accept an answer that lists an overview paper on the challenges of accurate flight simulation on modern computer systems.


texts: Does the FAA generally consider a door opening in an unpressurized cabin during flight to be an emergency?

texts:
Sometimes doors pop open on older training aircraft during flight.

I've read some indications from poorly-documented sources suggesting that this is considered an emergency, but it doesn't appear to be addressed in any flight manuals, the AIM, or the FARs.

Is there any publication from the FAA that indicates a stance on the issue as it pertains to it being considered an emergency or not?


texts: Could the US Air Force ever replace the Thunderbird pilots with drones?

texts:
Would it be possible or practical for the US Air Force to replace the Thunderbird pilots with drones?  The drones could perform more difficult maneuvers and do them more precisely.

The University of Pennsylvania is successfully working on small-scale formation flying.


texts: Why is wing anti-ice in transport aircraft not required below -40 degrees Celsius?

texts: Okay, this confuses me. As it gets colder doesn't it mean more possibility of icing? And is the -40 degrees SAT or TAT?


texts: Does the speed of the air molecules matter in aircraft performance?

texts: Does the fact that air molecules move slower in cold weather and faster in hot weather also affect the aircraft's performance or no? So if its cold there is a higher chance or air molecules hitting the wing and engines because the air molecules are compacted and slow moving and in hot weather they are spread out and faster moving, so less of a chance of air molecules hitting the wings and going into the engine. So in cold weather the molecules move slow and in hot weather they move faster, does this also effect aircraft performance. I know that the fact that in cold air the air is more compacted and that increases aircraft performance but does the fact that it moves slow also have an effect on aircraft performance? Same with hot air, the air is more spread out which reduces aircraft performance but does the fact that the air molecules are moving fast have an effect on aircraft performance?


texts: Can anyone identify the make and model of this aircraft? I'm just really curious.


texts: May I fly an aircraft registered in an EASA member with an EASA licence (NOT same country as airplane) outside Europe?

texts:
Let's say that I have an Italian PPL licence and with my I- registered aircraft (small Cessna example) I want to fly in the US or in Argentina, then ICAO rules allow me to do that. Am I correct?

(I think ICAO rules let you fly in another ICAO country if you have your licence and aircraft from same country)

Assuming that, would I be able to do the same thing if my aircraft is registered in another EASA country like Germany (D- registration)?

And a final question:  What if instead of PPL and Cessna, we put EASA glider licence and a glider?


texts: What will happen if satellite navigation fails?

texts: My understanding is that aircraft use GPS systems for navigation (maybe not the only way to navigate). I would like to understand what would happen if the GPS system fails.  Are there any other navigation systems to fall back on? What would happen if all of them fail? Could all the navigation systems fail?


texts: Does a flight training company need to make a copy of my driver's license?

texts: I want to get a Sport Pilot license, but the company that will train me wants to make a copy of my driver's license. I don't mind showing it, but is a copy required?


texts:
You may be surprised to find out that an airplane can stall at any attitude if the critical angle of attack is exceeded, but it cannot stall at 0 G.

This quote found in the April 2014 issue of Flying magazine, but it seems counterintuitive to me.

Why can't an airplane stall at 0G?


texts: Finding the center of gravity/centroid of an airfoil?

texts:
I'm in the process of building myself a wing frame out of balsa wood. However, as a high school student that's just started aerospace engineering, I'm not really sure how to go about it in some ways.

What I'm looking for is the center of my ribs so that I can find the best point to put my main spars in. The ribs themselves are full flat-bottoms if that helps any. Is there a go to equation for something like this?


texts: Does EASA approve the use of localizer back course? Are there some countries in Europe that allow it?


texts: Does Green Dot Speed Calculation include banking Angle?

texts:
I'm wondering, whether the Green Dot- speed calculation in the Airbus PFD does account for the actual bank angle of the aircraft.
Green Dot Speed is the speed for the best lift to drag ratio as it is stated in Safety first SPECIAL  EDITION: Control Your Speed Series.
In that edition, it is stated, that the Green Dot-speed is a function of aircraft weight, which is quite obvious.
I wonder however, whether the current roll angle is also accounted for as the hodographs like given in Avrenli, Kivanc, und Barry Dempsey. „Is “Green Dot” Always the Optimum Engines-Out Glide Speed on the Airbus A320 Aircraft?“ The Journal of Aviation/Aerospace Education and Research, 2015. suggests:

Any ideas how to get those numbers for Airbus aircraft?


texts: How to estimate blade interference in a propeller or fan?

texts:
The ideal propeller has one blade. For obvious reasons, that would be impractical.
However, adding more blades causes each blade to operate in each others slipstream/downwash.

How to quantitatively estimate this interference?In other words, what is the real angle of attack and airflow speed seen by each blade


texts:
Exemption 3585 allows 121 carriers (and perhaps others) to dispatch to destinations in certain cases with weather below minimums.

What are the forecast weather minimums to be dispatched under exemption 3585?  When is it required to have a second alternate listed on the release?  What are the forecast weather requirements at the two alternates?  What is the regulatory basis for this exemption?


texts: What are the take-off parameters for the B-25 Mitchell?

texts: What is the take-off distance and speed in standard atmosphere (59°F, 29.92 inHg, 0% humidity) for the B-25 Mitchell with max, minimum, or average payload?


texts:
Airplanes prefer to land into the wind, and airports adjust for changing wind direction by changing the active runway.

I've been flying a small plane in the pattern when the tower asked me to do a 180° turn to reverse the pattern.

But at a large airport with traffic continuously coming-n-going, with fast moving jets that fly enormous patterns, how do they switch directions?   It seems logistically complicated.


texts: Do fighter jets use elevators as ailerons?

texts: I saw jets in game using elevators to roll right and left, but I never saw them doing in real life. I was wondering if fighter jets actually use elevator to roll like they do in game.


texts: What is the horizontal and vertical fields of view for a VASI and a PAPI approach system as you come in to land?

texts: As you come in for landing, at what angles should the VASI or PAPI lights be visible on the approach in the Horizontal and vertical planes. {E.G. 30 degrees horizontal and 20 degrees vertical}


texts: Do aircraft designers gather real data to confirm their design (CFD, wind tunnel) data?

texts:
What  tools and techniques are used to get real data test to confirm the values that are obtained by computational fluid dynamics (CFD) calculations and wind tunnel testing?
Is this standard procedure for all aircraft before going into production?


texts: How are aircraft separated at high altitude?

texts:
When cruising at high altitude, a fixed-wing aircraft has less margin for adjusting its speed, due to the convergence of the stall "speed" and the overspeed limit:

If and aircraft has to be separated to prevent it to get close to a preceding, and ATCO asks to the second aircraft to slow down a bit, this may result in speed lower than the stall speed. On the other hand asking it to descend to a lower level may be costly due to fuel rate increasing.

What is the usual way to fulfill such separation need?


texts: Where can I find speed and thrust data for airplanes during the approach?

texts:
While trying to gather information on fuel consumption during the approach I have found this equation :

$$f=C_{f1}\cdot (1+V_{TAS}/C_{f2})\cdot T$$  (on this FAA paper)

$f$ is the fuel flow
$T$ is the thrust acting parallel to the aircraft velocity vector
$C_{f1}$ and $C_{f2}$ are the first and second thrust-specific fuel consumption coefficient
$V_{TAS}$ is the true air speed

From what I have understood Cf1 and Cf2 are constant and their values can be found (all the documents regarding these issues are 100 pages papers so I have not read everything yet).

I would like to plot the fuel flow for different airspeeds and thrusts. What are the typical values during the approach ?
I would like to have these data for several flights during the last 20 or 25 minutes of the flight.

What I am looking for is exactly what flightaware.com provides except that they use ground speed (an exemple here). How can I convert to TAS ?
Also they don't provide anything on thrust. Do you know where I can find thrust data ?


texts: How can I calculate the "stability state" of air from a given set of data?

texts: I would like to know the answer for the above question, it is about how to find whether atmosphere is stable or unstable using DALR (dry adiabatic lapse rate), SALR (saturated adiabatic lapse rate) and ELR (environmental lapse rate). The table also lists RH (relative humidity).


texts: In what ways does the current FAA written exam differ from the Sporty's practice test?

texts:
I am preparing to take my PPL written exam. I have been using the Sporty's practice exam program to gauge my progress? Recently I heard that the FAA has changed a few things about the tests. So I am curios: How the current written exam differs from the Sporty's practice exam?

Does the current written exam use the Airman Knowledge Testing Supplement for Sport Pilot, Recreational Pilot and Private Pilot?
Are the questions formatted in the same way as the practice question?
If you perform well with the Sporty's practice exam with an actual understanding of how you got to your answer, would you likely do well with the current test?


texts: How are unpaved strips created and maintained?

texts:
I'm under the impression that some large craft are rated for "unpaved strips", which appear to be either some sort of gravel or perhaps dirt.  The 727, and this runway, being a good example of this:

Picture taken from this question, which is also a good reference on how large airplanes can operate on "rough" fields.

What I'm wondering is how these fields are prepared?  I assume the ground is required to be able to hold up a certain amount of weight, and I also assume that ability must be uniform, or you'd be risking a wheel poking into the runway and basically ruining everyones day...

So how do they prepare/create these runways?  And how do they ensure that they maintain the ability to be used for operations with craft that are rated for "unpaved" but probably not rated for "random, somewhat grassy field."


texts: How do I choose the vertical tail's airfoil?

texts: I'm designing a fixed wing UAV and I'm having some doubts about how to determinate the vertical tail airfoil. It's important to say that we've already sized this surface. And till this moment we're using the software XFLR5 for the analysis.


texts: Why manufacturers does not producing variable sweep wing in our current scenario?

texts: I read about many types of aircraft wing configurations like rectangular, swept forward, swept backword, and Delta wing. These configurations have their own advantages and disadvantages. But why we don't have variable sweep wing so that we can gain the advantages and better efficiency.


texts: Is it reasonable for flight economy to correct banking tendencies with stick and rudder?

texts: An aircraft with side-by-side seating but only one person aboard should fly banked.  Banking decreases lift and more elevator is needed than in leveled flight which increases drag. Correcting the banking with ailerons and rudder also increase drag. Which is better for economy?


texts: Does a history of social anxiety significantly damage commercial pilot career prospects?

texts:
Yeah, I've had a history with social anxiety although it's all sorted now because I got therapy. I was wondering if it's important that I disclose this to employers or just lie if asked? Would they be able to find out? And yeah, if I did disclose this would it harm the chances of me achieving my dream of being a commercial pilot?

I ask this as I know people with a history of depression aren't meant to be commercial pilots.


texts: When do I have to contact Centre when departing/arriving at an airport with an ATF?

texts:
I'm looking at St-Frédéric airport in Quebec, Canada (CSZ4) and specifically at the "COMM" section. It says that there is an Aerodrome Traffic Frequency (ATF) on 122.8 but it also seems to say that you need to contact Montreal Centre (135.025) on arrival and departure:

Does this mean that Montreal Centre is to be contacted only when the ATF (UNICOM) is not operating, or do I have to contact it at all times?


texts: How are runway lights constructed so that they are not damaged by aircraft wheels, and can continue to function safely, to demanding specifications, under a wide variety of environmental conditions?


texts: How can static pressure be obtained over a range of airspeeds?

texts:
Multiple instruments rely on static air pressure, i.e. pressure unaffected by airspeed.
To my understanding, no such air should exist around an aircraft. Air in motion exhibits a lower pressure measured laterally, and a higher pressure measured head-on (ram air).
Switching to an in-cabin alternate static source usually decreases measured pressure, as the cabin altitude is above outside altitude, due to its equalizing with accelerated outside air.
The only solution I could think of was to measure pressure at an angle, where both effects (Bernoulli and ram, so to speak) cancel out. Now such an angle would be airspeed-dependent. How can a reliable pressure be obtained, without computational aid, over a range of airspeeds?


texts: Can an airplane lift off the ground when lift is equal to weight?

texts: Can a plane lift off the ground at the point when there is the same amount of lift as weight? Or does lift have to be greater?


texts: Can commercial air traffic operate from uncontrolled airport, airspace?

texts:
Are there any airports with scheduled services where big jets (say 737 or A320) or wide bodies regularly operate without control tower?

Are there any rules (EASA FAA) for this?

If controllers go on strike can commercial air transport continue to operate?


texts: I am a senior in high school who has been interested/fascinated in aviation. I do not know whether to go to a 4 year school to fly commercial for UPS or Fedex or do charter planes or fly for companies like menards. I am not sure of the benefits of either one. I’ve heard some work more days and some work less days. I just want to be committed on this before I spend a boat load of money for school.


texts: Is there a button that pilots push to transmit on the radio?

texts:
Is there any button which needs to be pressed when the pilot or co-pilot wishes to talk to ATC?

Normally in videos on YouTube they don't seem to be doing anything special other than speaking, but I believe that there's more to it. Probably the push buttons (like on a walkie-talkie) are located very close to their hands?

I'm generally asking about all aircraft that communicate with ATC, not any specific airliner.

Please note that I know the handshake stuff and the frequencies and the radio part of it. My question is only about whether they do or they don't have a push button when they have to send a message. It doesn't seem to be an always on thing because obviously that would clutter up the channel and ATC guys don't need to listen to what the pilots are talking in the cockpit routinely.


texts: What does a reduction gearbox do in a turbofan engine?

texts: I've read that the P&W PW1000G engine has a reduction gearbox. What is it and does it have any relation to the fan or compressor speed? Does it improve fuel efficiency?


texts: What is the effect of moving the centre of gravity ahead or behind the aerodynamic centre for HALE UAVs?

texts: I have heard a lot about keeping the centre of gravity (CG) behind the aerodynamic centre (AC)will give better performance than keeping CG ahead of AC (for UAVs require high performance). However, I could not find any example UAV/glider/sailplane which operates with CG behind AC. Can some one tell me whether there are any existing UAV/glider/sailplane with CG behind AC position?


texts: How do active blades work on helicopters?

texts:
Can someone throw some light on 'active blades' as used in helicopters? I'm mostly interested in the use of piezoelectric material and actuators.

How are the actuators able to sense the change of aerodynamic forces on the blade?
 What is the subsequent action of the actuators which results in a reduction of noise level of the rotor?


texts:
14 CFR 61.55 says:

  ...

  (d) A person may receive a second-in-command pilot type rating for an
  aircraft after satisfactorily completing the second-in-command
  familiarization training requirements under paragraph (b) of this
  section in that type of aircraft provided the training was completed
  within the 12 calendar months before the month of application for the
  SIC pilot type rating. The person must comply with the following
  application and pilot certification procedures:

  ...

  (6) The applicant must appear in person at a FAA Flight Standards
  District Office or to an Examiner with his or her logbook/training
  records and with the completed and signed FAA Form 8710-1.

  (7) There is no practical test required for the issuance of the “SIC
  Privileges Only” pilot type rating.

What exactly is an SIC type rating used for and how can someone get a "type rating" without any kind of practical test?


texts: What additional US-power or ICAO requirements apply to a departing US-based crew with a US-registered aircraft flying to land in Mexico?

texts:
What are additional requirements (equipment, licenses, identification, etc.) for a flight operation with a US-based aircraft and crew leaving the US to enter and land in Mexico that are imposed on the operation by the US authorities such as the government or any of its agencies and comprehensive international agencies such as ICAO?

This differentiates from similar questions because I am not asking about the governing set of laws in international territory or what laws of a different country than the home country would apply to the flight; of course ICAO is international in all cases so could be applied as valid in any home country that an aircraft may depart from.  Each other, non-US, country's specific laws may vary, so they are removed from the scope of my question.


texts: How are Max Brake Energy Speed & Weight affected by other factors?

texts:
I'm a student pilot and I'm trying to understand how different factors affect VMBE and Maximum Brake Energy Limited Take-off Mass. I made some researches but I couldn't find anywhere a clear answer.

What is the effect of Density, Flaps, Mass, Runway Slope, Runway Contamination ?

I know that to solve these kind of problems we use the kinetic energy formula: $\small Eb = \frac 1 2 MV^2$ but I don't know how to use it to explain the effect of every factor mentioned above.

(I need your help because I don't want to just learn things by heart and not be able to explain that in an interview or whatever).


texts: Should I land a Cessna 172 with or without a little power?

texts: Cessna 172 landings with full flaps. I have been taught to land with and without power. Give me feedback please. Which way should I continue my training?


texts: What qualifications are required to become chief instructor at a 141 flight school (FAA)?

texts: Under the FAA jurisdiction flight school operations can be conducted under the provisions of part 61 or part 141. If a flight instructor wanted to become a chief instructor at a part 141 flight school, what would they need to be qualified?


texts:
I have verified numerous approaches from the NW to PVR airport and they all look like this, basically approaching on the left side of the mountain then taking a right towards the airport:

But then noticed 1 flight whose path is different:

Do you think that was the intended flight path or they suddenly realized they need to be further to the left ?


texts: Has anyone built an aircraft with a flat ring wing?

texts:
When I try to search for circular wing aircraft, everything I find has the wing loop up over the top of the craft.
What I want to see, however, is basically an Aerobie Flying Ring, but with a motorized propeller, etc.
I'd be equally happy to see a "real" plane, or an RC one.
Also, while I would expect the wing to be attached to the fuselage via cables, I'd be equally interested in learning about alternatives (e.g. blended wing).


texts: Why is there a grid below the antennas of an VOR?

texts:
A few days ago I made a trip to the VOR-DME near my local airport LOWG, because I always wanted to see one. It's GRZ on 116.2.

When I was there, I wondered why there is a giant metal grid under the actual antennas of the VOR.

Source: Klaus Krasser

Close picture:

Source: Klaus Krasser

The grids squares have a size of estimated 10x10 centimeters.

What is this grid for? Is it maybe used as a shield or reflector? 116.2 Mhz has a wavelength of ~2.6 meters, so the grid would reflect the radiation. If thats the use of the grid, why is it needed?


texts: Where is the APU in the case of an S-duct (like the L-1011)?

texts:
This question asks about the S-duct of the L-1011 Tristar. Fooot's answer shows a cut-out of the L-1011. Looking at this cut-out, I'm wondering:
If the engine is at the 'normal' location of the APU, where did the designers of the L-1011 put the APU?
I did a search, and found this site which mentions

The APU is located in a compartment in the aft fuselage.

Another site mentions

Its still in the "tail". Its mounted below the #2 engine. Just forward of the tail skid.

But I don't see how you could fit the APU in the small available space.


texts: Which instruments are assigned to Pilot Flying and Pilot Not Flying in the various flight stages?

texts:
Is there a document which highlights the responsibilities of the Pilot Flying and the Pilot Not Flying? Specifically, I want to find out what instruments are assigned to whom in all the stages of flight.

I haven't had any luck in finding any documents which highlight these points.
So far I have read through the FAA handbooks but to no avail.

For example:

During takeoff, PF focuses on X and Y but PM monitors X, Y, A and Z
Then during descent, PF focuses on C and F but PM monitors C, F and A

Are there any resources which I have failed to look at? Does any document explain this?


texts: What are the heating tubes used during SR-71 airframe manufacturing?

texts:
I was watching a YouTube video "Titanium - The Metal That Made The SR-71 Possible" when I stumbled upon this frame (at 12:26).
I could see these heating tubes sort of things under the airframe. What exactly are these and what benefit do they add during the manufacturing process to the airframe?


texts: For an aircraft, what are the differences between nonlinear and linear equations of motion?

texts:
So, as far as I understand, linearized equations of motion are just nonlinear equations of motion converted to linear EoM's using approximations and assumptions to simplify/remove elements from the equations.

In an aircraft, what are these nonlinear EoM's? If, for example, I stuck my airplane in a wind tunnel to determine the entire set of aerodynamic coefficients, would that cover all of the nonlinear portions of the equations of motion?

Thanks!


texts: Why can't helicopters fly at high altitudes?

texts: I recently watched a movie and in the movie it stated that the helicopter could not fly to the top of mt.everest to rescue the person stuck on the top. So why can't helicopters fly at such high altitudes?


texts: Is there an instrument departure procedure or minimum performance gradient in the absence of a published standard instrument departure?

texts:
Is there an instrument departure procedure or minimum performance gradient in the absence of a published standard instrument departure (SID)?

Departing under instrument flight rules (IFR) in the United States airports sometimes have a SID procedure or alternate take-off minimums which must be observed in order to provide terrain and obstacle clearance.

If there is no SID or alternate take-off minimum published, is there a standard departure procedure to be used in the absence of other procedures? Is there a climb performance gradient which is assumed that provides clearance under such a departure?


texts: How to extract the interrogator ID from a DF11 message?

texts:
I've written a class which decodes raw Mode S messages.  Whilst browsing the ICAO specs the other day I noticed that the Interrogator ID is sent back in the DF11 message.

I thought that it would be a fun exercise to determine where in my coverage area interrogations from particular radar installations can be seen.

But I'm having a really hard time figuring out how to extract the interrogator ID.

For this DF11 message:

5D406FDB0D62DD

I've got the following:

Binary: 01011101010000000110111111011011000011010110001011011101
Integer Words:
    [0] => 93
    [1] => 64
    [2] => 111
    [3] => 219
    [4] => 13
    [5] => 98
    [6] => 221

 CA: 5
 AA: 4222939
 Address: 406FDB
 Parity: 255
 Residual: 0

As the Residual value is 0 I know that this is a valid DF11 message and the address checks out as well.

From the ICAO spec:

"The code used in downlink PI field generation shall be formed by a sequence of 24 bits (a1, a2,..., a24), where the first 17 bits are ZEROs, the next three bits are a replica of the code label (CL) field (3.1.2.5.2.1.3) and the last four bits are a replica of the interrogator code (IC) field (3.1.2.5.2.1.2)."

In that case I would expect the end of the last three integer words (4,5 and 6) to be mostly 0's but they aren't.

I've gone through the documentation numerous times but just can't see how to get the II and SL codes out of Parity value ?

I'm calculating the Parity value by doing the following:

$this->_pi = $this->_int[4] | $this->_int[5] | $this->_int[6];

where | in PHP is the OR operator.  Is this my mistake ?


texts: If I were to scratch build a helicopter, as the manufacturer, would I need a pilot's license to fly it?

texts: If I were to scratch build a helicopter, as the manufacturer, would I need a pilot's license to fly it while its in the experimental stage?  This is in the USA, but I'd be interested in how it plays out in other countries which are different


texts: Is "laze" (lava + haze) as hazardous as volcanic ash to turbo engines?

texts:
Reading an article about Pahoa, I read that erupting Hawaiian volcanoes produce a combination of lava and haze - resulting in clouds that contain hydrochloric acid.
 Are these as dangerous as volcanic ash clouds?  What are the possible consequences for nearby flights?


texts: What are the pros and cons of buying a kit aircraft vs. a factory-built one?

texts: I am a student pilot, and I am trying to decide on what I should do for a plane. I am leaning towards buying a kit, but what are the advantages or disadvantages for that?


texts: How much power is generated by a Ram Air Turbine (RAT)?

texts: For long range, wide body planes A380 and B777, what is the power generated by RAT (Ram Air Turbine)? And which all are the systems which the RAT drives?


texts: What's the difference between SLG strut used in B777 and truck position actuator used in any other aircraft like B747?

texts: Do they serve the same purpose ? If not what's different ?


texts: How would you use the mental clock code to solve this dead reckoning problem?

texts:
Can someone explain the question below in details?

You plan to fly a cross country flight at 2 000 feet at a true airspeed of 120 knots. Your track is 270° (True) and the wind is from 225° (True) at 24 knots. Using the Mental Dead Reckoning Clock Code, what true heading would you steer, and what would be your magnetic heading if the local magnetic variation is 4° West?


texts: Why don't the A380 and A350 have trim wheels?

texts:
(wikimedia.org) A350 thrust levers without the flanking trim wheels.

Why don't the Airbus A380 and A350 have trim wheels?

On the other fly-by-wire Airbus aircraft the trim wheels are there for manual trim in case the aircraft went into direct law since the Airbus sticks do not have a trim control.

Were the trim wheels replaced by another interface? Or is the manual trim option completely removed due to a certain [backup] technology?

Left: Standard Airbus sidestick on the A350 with no trim control (wikimedia.org). Right: Trim wheels on other Airbus aircraft (wikimedia.org).

The question stems from this comment:

  I don’t think [having trim controls] is strictly speaking necessary. It used to be the mechanical backup for FBW failures on early Airbusses, then it was kept a while for commonality. I am not sure whether the A350 still has it?


texts: How is the control of airspace over disputed territories determined?

texts:
Reading this question about the division of airspace over the Persian Gulf reminded me of another potential issue regarding Persian Gulf airspace: the numerous territorial disputes in the area, such as the dispute between Iran and the United Arab Emirates over several islands (Abu Musa, the Greater and Lesser Tunbs, Sir Abu Nu'ayr, and Zirku) scattered over a large area of the lower end of the Gulf, and the unresolved issue of how far northwest the United Arab Emirates extend.

How is the ownership and control of the airspace over these and other disputed areas around the world (of which there are rather a lot) determined?


texts: What is the material that is used for turbine blades that has the highest melting point?

texts: What is the material that is used for turbine blades that has the highest melting point ?


texts: What does the letter "D" next to the VOR frequency and name mean?

texts: In most charts there is the letter D next to the VOR freq. What does this mean? I assume the H and L in brackets in other charts mean high and low VORs (correct me if im wrong). But what does the D itself stand for?


texts: Why does the B-52 take off without rotating?

texts: In the answer to this question it is noted that the B-52 takes off without rotating and climbs out in a nose-down attitude. Why was it designed this way?


texts: How can two private pilots flying together log time and split costs legally?

texts:
I'm a new private pilot and I've got a neighbor who would like to do some flying in his personal Cessna 172G.  He is a private pilot as well and I am wondering how the regulations apply.

If he sits at the controls as a pilot (not a passenger) and pays for all of the expenses of the flight is that illegal? Even if I am PIC, do the regulations have be considered under pro rata, even he is not a passenger? I'm confused on how the regulations cover this.

He'll also cover the expenses of me flying with a local CFI to get checked out in his 172G, since I built all my time in Citabrias.  I'm confused about the regulations and don't want to do anything that may jeopardize my license.

As far as the arrangement goes, building time would be the closest thing that I could think of. It's his aircraft and he said he would be willing to pay for everything. This could include just local flights, getting a feel for the 172 and building time. I would think he would allow me to borrow it to fly solo as well, once he feels comfortable with me doing that. If it's the two of us just flying around, does it just become a matter of who is PIC? If we discuss that he's PIC and can take over any time, but lets me fly a lot does pro rata still apply? If he's always PIC, then he has to pay at least his share, but could cover all costs. But how does that leave me for logging any time? I'm unsure on how the regulations consider this, since we're both private pilots at the controls.


texts: How can this aircraft be stable/maneuverable?

texts:
The new wave of electric VTOL aircraft concepts (Joby Aviation, Zee, Lilium, Airbus A$^3$, etc...) has produced some audacious unconventional designs.
Now my question, is how Lilium's concept can be stable and/or maneuverable, given the following configuration:

What strikes me is a lack of a surface that creates a force to counteract the momentum generated by the distance between the wing's lift and the gravitational force.
And although control around the yaw axis seems possible with differential thrust, I wonder how the aircraft is controlled around the pitch axis.
From the forward part of the fuselage some canard-like surfaces with integrated propellers are deployed to provide hovering capabilities, however it seems these are supposed to be retracted during forward flight.

Some might suggest the pictures are pure artwork, but Lilium and its investors appear to believe in the concept:

10m€ funding from London-based venture capital firm


texts: Why does an aircraft pitch up when the speed increases?

texts:
Can anyone please explain why aircraft pitches up when the speed increased? (please consider an aircraft, Wing AC, CG and Tail AC lies on a line.)

The ideal explanation I'm looking for should have something to do with the static margin.

Here I am talking about a powered or unpowered aircraft, trimmed for steady flight, reacting to an EXTERNAL velocity perturbation which increases the airspeed. (Like a sudden, substantial, sustained increase or decrease in the speed of the wind, e.g. due to wind shear.)

I have seen that when faced by this kind of a perturbation, the aircraft tries to slow down/keep the airspeed unchanged by increasing the pitch angle.  My question is how it happens

Peter Kampf wrote:

  However, I can imagine what might have happened to let you observe a pitch-up. This needs several conditions:
      A propeller-diven airplane with the propeller in the front
      A sufficiently large static margin so the empennage produces a down-force.
      Speeding up by opening the throttle.

Let me clarify these are not necessarily the cases for what I'm asking,
    1. If we throw a glider hard enough, which is trimmed for a certain airspeed it will pitch up and climb.
    2. At least for now I think it doesn't matter whether the tail produces down-force or upward force. Say the velocity is increased by factor of 2 and the forces on both wing and tail increased by a factor of 4. Equilibrium is still maintained as moment around CG has not changed by this. (and this is what stands against my observation)

Mike Sowsun wrote:

  The horizontal stabilizer always provides a downward force to balance the forces of lift and weight with the center of gravity. This also provides stability because if the aircraft pitches down and starts to speed up, the increased airflow over the tail will result in more downward force and cause the nose to rise and the aircraft to slow.

I think there is no need for the tail to make downward lift always. The tail can be uplifting as well. Anyway, if we agree that to be the case for now, when the aircraft gains airspeed, the flow speed over the wings increases as well as tails. Isn't it? What I can't understand is, what makes the aircraft pitch up when both the wing force and tail force increased by the same factor, due to increase of airspeed.

Any further input is much appreciated.


texts: Is it possible to fly a large aircraft inverted?

texts: I am curious if the inverted plane in the movie Flight 2012 has anything to do with reality / emergency practices. And if it does, can you please explain the concept/ aerodynamics behind of it , or why someone would ever do that even as last resort?


texts: What is the actual exhaust velocity of the exhaust from the J58 engines at cruise (Mach 3.2)?

texts:
The SR-71 ran on two J58 turbojet engines and cruised at Mach 3.2.

What I want to know is, what is the actual exhaust velocity (relative to the airplane itself) of the jet exhaust at those conditions?


texts: I trying to find a way to stay in a jet stream unpowered for a larger question. Is there a glider, kite or plane that flies best when in turbulent weather?


texts: What is the temperature of flap linkages during takeoff and landing in passenger and fighter aircraft?

texts: During takeoff and landing, what is the temperature of flap linkages in passenger or fighter jet aircraft?


texts: Why are some A350s missing SSA probes on their nose?

texts:
I recently just noticed that some A350s are missing their iconic set of 3 main SSAs (Side Slip Angle Probes) on their nose. I'm not sure if its an issue of newer variants or varied airline options, but I'm sure it has something to do with a less needed sense of redundancy. Any exact answers behind this?

Thanks!

Picture sources:
Top:https://www.traveller.com.au/the-inside-story-of-the-a350-airbus-rival-to-the-boeing-787-dreamliner-12c17x
Bottom: https://airwaysmag.com/airlines/british-airways-takes-off-a350-1000/


texts: Do flight tracking websites also track non-commercial and defense aircraft?

texts: Many flight tracking websites have the data about almost all the commercial airplanes in air. Do they have the data about the private jets and/or defense aircraft also and they just don't show that on the websites?


texts: Why are airplane passengers boarded from front to back?

texts:
Last time I boarded a flight (Boeing 717 with Delta, with assigned seats), the passengers were split into 4 groups and allowed to board the plane in an order that filled seats from front to back. I can understand why first/business class could go first, since they pay more. But the rest of the passengers pay the same rate.

Wouldn't it be more efficient to let the passengers that sit in the back board first? Or maybe even to just let everyone board in random order.


texts: How does rudder size influence its ability to produce lateral lift?

texts: Does anyone know how the area, height and width of a rudder affect how well it provides lateral lift? I've heard that the most effective rudders are around 35% of the vertical stabiliser MAC but is there any maths to back this up?


texts: Fine for operating not single-pilot certified jet with one pilot

texts:
Are there any clear-cut fines for flying an aircraft like a Global 5000 which is not single-pilot certified by a single pilot?

And what would be the probability of being caught and how would they catch you?


texts: I'm reviewing the Sporty's ground school for VOR approaches, and their example shows the approach to the VOR station then heading OB as tracking on the holding side. What if you approach the VOR station such that your turn OB is not on the holding side? I know conventionally that side is not the protected side of a hold, but does the hold side matter for that timed turn? Are you typically just vectored such that you approach the station and turn OB on the protected side of a holding pattern?


texts: Why does the Trent XWB have intermediate compressor stages?

texts:
I realized that the Rolls-Royce Trent XWB on the Airbus A350 has intermediate compressor stages. Why is that?

Other engines like the CFM56 or IAE V2500 that power most of the A320-family have low pressure compressor stages (including the fan), and not intermediate ones. And the Trent XWB doesn't have a low pressure compressor. Unless the fan counts as one.

Is the low pressure compressor just the fan on the A350 and they don't call it a fan?


texts: To which reference point on the aircraft is the altimeter reading relative to?

texts: To which point of the aircraft is the altimeter reading referred to? Is it referred to the probe position or is it offset to read as if it was at the bottom of the fuselage or the landing gear? If it was a GA aircraft I suppose it wouldn't make a difference, but on something big as a 747 or an A380, should it be set at the same level as the probe, there would be quite a difference compared to the ground (maybe 20-30 feet?). If so, how is this handled?


texts: How do pilots of big jets determine if they are clear of the runway after landing?

texts:
The pilots of small aircraft can easily determine if they're clear of the runway by visually looking back through the side windows.

How do the pilots of big commercial jets determine that all parts of their aircraft are clear of the runway after landing? It looks like the same visual check as used by GA is almost impossible given the size of their aircraft. Do they have some special ways or measures to do that?


texts: What is this white rectangle painted on runway 23 at KCRW?

texts:
(Related to this question.)

Runway 23 at Charleston, WV (KCRW) appears to have a (roughly) 500' x 50' white rectangle painted on the touchdown zone (I've added red arrows pointing at each end of the box):

Source: Google Maps

What is it used for?


texts: A commercial jet with rear tail-mounted engines and 3+3 seat pattern?

texts:
I have just spotted a cameo in one of the old CSI:NY episodes. External shot showed a commercial jet, rather big aircraft, with rear tail-mounted engines. While internal shots shown 3+3 seat rows configuration and around 150-180 passengers.

Is this combination ever possible or is this an in-movie mistake?

I was always told that rear tail-mounted engines are capable of powering smaller aircraft only (like MD-8x and Canadairs) which are always configured in 2+2 seat rows set and are capable of delivering around 100 passengers at most.

What am I missing (note that I am not talking about trijets)?


texts: Does a left spin differ from a right spin for a single-engine propeller aircraft, in terms of spin characteristics & ease of recovery?

texts:
Given a single-engine propeller aircraft with its nose-mounted propeller rotating on the right-hand side when viewed from the cockpit, and given the typical effects like P-factor, prop-wash and gyroscopic forces associated with the propeller -

Would there be any differences between left-hand and right-hand spin modes? (Differences both from the physics perspective as well as perceptional difference from the pilot's point of view. For example, the differences could be there from a theoretical perspective but minor enough that the pilots can ignore them in real life).
If the answer is yes for Q1, which side, in this particular case, would have a more severe spin in terms of spin rate, loss of altitude and so on?
If the answer is yes for Q1, which side, in this particular case, would have a harder recovery compared to the other side?

To reduce variables, let's assume there are no asymmetries in the aerodynamic configuration which may make the aircraft favor one direction over the other for  spin and we are only considering the effect of propeller-rotation-direction-related effects on the spin.


texts: How can I overlay a VFR sectional on another map to identify features and landmarks?

texts:
How do I know which highways and landmarks on a VFR sectional align with which real-world features? Is there a way to overlay the VFR sectional map from the FAA on top of Google Maps or Bing?

Edit: I'm asking in relation to VFR flight in general where you are responsible for your own navigation, and not about a specific route of flight.


texts: Why does landing gear retract with an offset?

texts:
I've noticed this often in flight simulators, and have, to be honest, never paid attention to it in real life, though I'm quite sure it happens there too:
When landing gear retracts (and I believe when it extends as well) the two main landing gears don't move simultaneously, but one goes up (down) earlier than the other one.
Here is a video that shows this as well: Video
As a matter of fact it appears one of the flaps that open the landing gear bulk goes down faster? Doesn't that cause aerodynamic disadvantages?
There has to be a reason behind that. What reason is this?


texts: What is a red airway on the VFR sectional?

texts:
The VFR sectionals show a number of airways/routes marked in red. Here are several near KMTH, you can see B-646 extending east of the NDB:

There are others in Alaska that are lettered A, R or G, e.g. A-7 runs between the CMQ and MNL NDBs.

What are these airways or routes and how are they different from Victor airways?


texts: If winglets reduce induced drag, induced drag is greatest at slow speeds. When are winglets most effictive?


texts: How to model aircraft fuel consumption during the approach?

texts:
I am trying to write an algorithm modelling the 'Airplane landing problem'. The aim is to land a sequence of airplanes while minimizing the operating costs and respecting constraints such as the separation between consecutive airplanes.
Hence, I need to be able to quantify these operating costs in particular fuel consumption.

Basically, in my simulation - it's a very simple approach - airplanes can be in 3 different regimes :

the aircraft can be asked to fly faster than it's preferred speed, it's called time advance and it's one of the tools used to reduce congestion
the aircraft can of course fly at it's preferred speed
the aircraft can be asked to fly a holding pattern

I would like to elaborate a function that would give the fuel consumption in function of the time for every mode.
I absolutely don't know where to start. The only information that I find deal with the preferred speed consumption.
How can I model the two others regimes ?

Edit : Indeed, the part concerning holding patterns is similar to this other question. However, I don't think any information on time advance has been given so I would like to focus my question on this. Also, if anyone has more information on fuel consumption in holding patterns than would by very helpful.
Thank you very much


texts: Who decides the regular procedure followed by the pilots before takeoff?

texts: Pilots need to go through a checklist before they take off. Are these procedures decided by the airlines and (or) the manufacturer, or by the Civil Aviation Regulatory Authority of the respective country?


texts: Helicopter or Airplane, which is the most difficult to fly?

texts:
I know it varies from aircraft to aircraft, but I want to know in general, which would be the most difficult aircraft to fly even after years of experience. Helicopter or Airplane ?

I tried to fly a helicopter on the FSX and I couldn't land the aircraft once without spinning like a beyblade for minutes. I know it is not possible to fly something perfectly without knowledge, but I remember that my first time flying a plane on the FSX, everything had been easier.

Some people also say that the wind greatly influences the helicopter on landing, which makes me think that perhaps the helicopter is more difficult to fly.


texts: How do you know which fuel an aircraft uses?

texts:
Other than the decals on the plane, how would you know what fuel to use in an aircraft? Where is this limitation documented?

For some aircraft, does this limitation include some sort of substitute fuel for emergencies? For example, I have heard that if Jet A-1 is not available, some aircraft may have approved emergency fuels, such as AvGas.

Where would this information be found?


texts: What is a (rough) rule of thumb for calculating fuel consumption in a modern jet airliner like Boeing 737 - 300?

texts:
I'm wondering what would be a rough rule of thumb for calculating the fuel consumption of a modern airliner like a Boeing 737 - 300.

I am not asking for anything from the plane's manual or even a rule of thumb to be used by pilots, but rather a "general idea", to be able to compare the fuel consumption of different modes of transportation.I am citing the Boeing 737 - 300 as an example as it is a pretty common type of airplane, but feel free to answer for another type of passenger aircraft.


texts: Why did the Mercure use cascade-type reversers?

texts:
There are three main types of jet-engine thrust reversers:1

Target-type reversers are seen on most civilian turbojets and low-bypass turbofans;2 they have the instantly-recognisable buckets that swing out behind the engine to deflect its exhaust (from both the engine core and - if present - the bypass duct) forwards.
Clamshell-type reversers, seen on some turbofans (both low- and high-bypass) have (as the name suggests) clamshell-style doors that open up from the engine cowling to deflect air forwards.  Clamshell reversers on low-bypass turbofans (“hot” clamshell reversers) generally deflect both the core and bypass air, while those on high-bypass turbofans (“cold” clamshell reversers) usually only bother deflecting the bypass air (which reduces maintenance costs and makes the reverser mechanisms last longer).
With cascade-type reversers, seen on most high-bypass turbofans, the entire rear portion of the cowling slides rearwards, diverting the engine’s bypass air forwards through the resulting gap.

Turbojets and low-bypass turbofans generally3 use target or hot-clamshell reversers, as much of the engine’s thrust (or all of it, for turbojets) comes from the core airflow, and said airflow thus has to be deflected forwards (along with the bypass air, if any) in order to produce net reverse thrust.  In contrast, high-bypass turbofans, the vast majority of whose thrust comes from the bypass air and only a  small portion from the core airflow, can get away with only deflecting the bypass air and leaving the core airflow alone (and thereby saving on maintenance, because jet engine core exhaust is really really hot and filled with delightfully corrosive combustion [by]products); as a result, they mainly use cascade or cold-clamshell reversers.

Enter the Dassault Mercure (an unsuccessful French jetliner from the seventies strongly resembling a longer, shorter-ranged 737-200), which used a pair of low-bypass JT8Ds, and, yet, if this photograph of a landing Air Inter6 Mercure is any indication...

...used cascade reversers.7

I’m having trouble seeing how this would work; for the engines to actually produce reverse thrust, rather than (an albeit diminished net amount of) forward thrust, would seem to require - for the reasons stated above - the use of target or hot-clamshell reversers, which redirect both the core and bypass airflow, rather than cascade or cold-clamshell reversers, which redirect only the bypass airflow.

What am I missing here?  Did Dassault have some magic trick up their britches, were the Mercure’s reversers meant merely to reduce the amount of forward thrust generated (and not to produce actual reverse thrust), or is that picture not what it looks like?8

1: For diagrams of the various types of thrust reversers, see the thrust-reverser tagwiki.

2: Low-bypass turbofans (seen on most narrowbodies designed from 1960 through 1980) have a bypass ratio less than 5:1, and generate the majority of their thrust from the engine core; high-bypass turbofans (seen on all widebodies except for one early Soviet design and on most post-1980 narrowbodies) have a BPR equal to or exceeding 5:1, and get most of their thrust from the bypass air.

3: For obvious reasons, I am ignoring jets that don’t have thrust reversers (such as essentially all fighters, early Caravelles, the BAe 146,4 and the F28).

4: I am aware that the BAe 146 uses high-bypass turbofans; footnote 3 applies to all jets, not just turbojets and low-bypass turbofans, but I couldn’t think of anyplace better to put it.5

5: Hey, I can nest footnotes!

6: The type’s only customer (Dassault sold them nine production Mercures, then refurbished the prototype and sold that to Air Inter as well).

7: (Image originally by Eric Salard at Flickr, via Dura-Ace at Wikimedia Commons; shrunken by me.)

8: Well, it’s definitely a Mercure either landing or rejecting a takeoff (as evidenced by the extended spoilers), but maybe what appear to be cascade reversers aren’t what they seem to be?


texts: Why are some aircraft built in a single country, whereas others are a collaboration of many countries?

texts:
The USA has developed numerous aircraft; Sweden developed the JAS Gripen and France developed the Rafale, by themselves.

But most of the modern aircraft developed by the UK and Germany needed collaborations. Yet both of them have the technology and enough money to build aircraft on their own. Why did the Eurofighter need collaboration among four countries?

On the other hand being a collaborative effort, the F-35 became one of the most problematic projects in aircraft history. So why collaborate?


texts: Does it violate any regulations for a bag to sit on the flight deck floor?

texts:
Pilots who fly the Canadair Bombardier Regional Jet or CRJ aircraft know first-hand how cramped the space on the flight deck is. It's really a business jet cockpit, not the flight deck you'd expect on a transport category aircraft. I have heard that it's not uncommon for pilots to keep a small lunchbox on the floor of the seat next to them.

Some pilots say that a bag cannot be stored there next to the seat and that if an FAA inspector were to see the bag, there could be consequences.

Is there a regulation that storing a bag in this way violates?


texts: What regulations discuss the red/white marked areas on a tarmac at a terminal?

texts: This is the terminal at KSTS. Someone mentioned to me that your can't overfly this area. (I fly helicopters direct to the ramp adjacent.) What regulations discuss this? I don't see it in the AIM.


texts: What are the mechanisms fitted in the SA321G Super Frelon rotor head?

texts:
Past the cyclic-collective pitch control, I understand (maybe incorrectly) that additional mechanisms are required to prevent or limit vibrations and loads on the mast and the blades.

Aerospatiale SA321G Super Frelon, photo by Burkhard Domke (source)

There are other rotor heads that are very simplified:

Bell AH-1 Super Cobra (source)

Can you explain what are the main mechanisms in the Super Frelon rotor head, and why the simple rotor head design is not used?


texts: Why does lift curve slope increase when Fowler Flaps are deployed?

texts:
Below is an image for a Fowler Flap:

Notice that as the flap is deployed, both the camber and the area increase. This change in wing shape modifies the lift curve as follows:

(source: Development of a Fowler Flap System for High Performance General Aviation - Wentz (NASA))

This behavior can be isolated and viewed in the simpler figure below:

Note that the lift curve slope has increased.

Here is my analysis:
If Fowler Flap is deployed, the planform area increases.
If the planform area increases, the aspect ratio decreases (since wing span is unchanged).
If AR decreases, then the lift curve slope should decrease (see How does the aspect ratio of a wing impact its lift? for details).

So where in my analysis do I go wrong? I know the lift curve slope should increase, then why does my analysis indicate otherwise?


texts: How safe are commercial airliners from gallium infiltration?

texts:
I recently saw a video on gallium infiltration on YouTube.  Gallium is a metal with a melting point somewhere between standard room temperature and human body temperature, meaning if you pick up a block of it sitting on the table, it will melt in your hand.  If this melted metal comes into contact with solid aluminum, it will seep into it and alloy with it, decreasing the strength of the aluminum to somewhere around that of tissue paper.
When I saw this, I immediately had a horrifying thought: aren't airplanes made of aluminum?  And when I've flown in the past, I've seen a few places where there's exposed metal.  This makes me wonder if a malicious person with no regards for their own safety wouldn't be able to bring down a plane with a novelty for children that anyone can buy for a few dollars.
If someone tried to do this, is there anything in the design of modern commercial airliners that would stop them?


texts: What is the process for requesting flight following in Canada?

texts:
In US, the process to get flight following is pretty straightforward. You call the approach/center frequency, request a flight following and you get it.

On a recent flight originating from a Canadian airport (Lachute, CSE4), I contacted Montreal approach after takeoff and requested flight following. They asked me if I had filed a flight plan. I said no, and they asked me to speak to Quebec radio so that a flight plan could be filed, Quebec radio will then give me a number and I am supposed to call Montreal approach again with that number. I contacted Quebec radio and the lady asked me a number of flight plan related questions and then asked me to standby. She never came back. Can someone elaborate on this?

What is the general process to get flight following in Canada?
Is a flight plan required to get flight following?
On another flight originating in Canada (CYKZ - KFRG), I was able to get flight following via Ground Control. So I am guessing a flight plan is not always required. What is so special about Montreal? How am I supposed to know which centers insist on a flight plan before they will provide flight following?


texts: (Why) Do airliners travel together sometimes?

texts: While browsing through the planes in FlightRadar (once again), I've noticed that sometimes some airliners from the same airline company seem to travel "together" on long distance flights to destinations located relatively close to each other (Like Finnair from Helsinki to Hong Kong and to Singapore or to different Japanese cities). The planes were separated vertically by about 2000ft but otherwise quite close to each other. Is there any advantage to this or a good reason? Or is this a pure coincidence?


texts: Partial panel power on stall under the hood

texts: What do you use for control and performance instruments while demonstrating power on stall under the hood with attitude and heading indicator covered (No vacuum instruments in 6 packs ) ?


texts: Can fuel be stored in the anti-shock bodies?

texts: lets say an airplane needs to get to a certain route but doesnt have the fuel to do and it needs to store in the anti-shock bodies. Is it possible?


texts: What methods are used to make a turbofan engine spool up quicker?

texts: In cases such as a low altitude stall the quick application of power might get a pilot out of a sticky situation, but turbofan engines are fairly sluggish in increasing thrust. If throttle is applied to quickly it can even cause a surge. I'm assuming the problem is the inertia of the fan and compressor. What things do engine manufacturers do to make the engines more responsive? What are the tradeoffs? Do other types of engine (turboprop, turbojet, etc.) suffer from the same problem of delayed response?


texts: I’ve got a problem with understanding propeller windmilling. What I know is that when rpm are low and tas is high the blade aoa goes „over” the blade and is some kind of negative now, producing thrust in opposite direction than usual. But I don’t understand what really happens there. Is prop rotating in opposite direction or sth? I also read somewhere in the atpl book that when prop is windmilling the prop is driving the engine. How is that possible? Can somebody clarify that to me?


texts: How should I decide whether to pursue an EASA ATPL or an FAA ATPL?

texts:
What are the advantages/ disadvantages of FAA vs EASA ATPL's, and does this translate into the real world with airlines preferring one training standard over the other?
As a trainee pilot, it's pretty confusing looking at the array of courses offered around the world, with huge number of flight schools all advertising ATPL courses under different jurisdictions.

Any insight, experience would be very helpful.


texts: Do different types of missiles indicate different lock tones to the pilot?

texts: Are there different lock tones for different types of missiles, e.g. air-to-ground (AGM) or anti-ship (AShM)? If so, what information do the tones give the pilot? Are they a way for the pilot to know which type of missile is selected?


texts: Why cycle the magnetos before engine shutdown?

texts:
Inspired by this question asking about shutting down a light aircraft engine I realised there is another ritual which I do, but have long forgotten the reason why.

Having parked a light aircraft, and switched off the electrics, with the engine still running I always check left and right magnetos, similar to the magneto drop check done as pre-flight checks.

I don't really pay much attention to the RPM, I do it because I've always done it. It's not (as far as I remember) on my shutdown checklist - and I'm starting to wonder why I do it.

Is this necessary? Something in the back of my mind is saying "prevents mag fouling". What is the real reason to cycle Left & Right mag pre-shutdown?


texts: Why would you NOT lean on takeoff with a Lycoming engine?

texts:
There is an excellent question/answer on leaning here. However what I have not yet understood is why one would NOT lean for takeoff below 3000 feet? Why does the Lycoming Service Directive 1497A/B still say to use Full Rich on takeoff?

Is it not right that a leaned engine is producing its highest power output and would you not want the highest power output on takeoff?


texts: How do airlines dispose of a passenger jet when it's no longer airworthy?

texts: When a plane is finally considered to not be airworthy, what happens to them?  Do they take them apart bit by bit?  Do they sink them offshore to make them into reefs?  Are parts stripped and sold as spares? Are there legal procedures the airlines have to go through?  What happens?


texts: Compute Thrust from RPM and Induced Velocity

texts:
I'm attempting to calculate the difference in thrust in a secondary propeller operating in the wake behind a primary propeller, in the context of a trailing quad-copter following a leading quad-copter in close proximity.

I'm using the model from Propeller Slipstream Model for Small Unmanned Aerial
Vehicles and have so far simply linearly superimposed two of the induced velocity fields on top of one another, as far as I am aware a linear superposition should give a reasonably accurate induced velocity field for now.

I'm wondering if there is a way to calculate the thrust a propeller is creating just from this induced velocity field. I should also note that the thrust the propeller generates is one of the input variables into the model, so I am assuming that I will need to work out how much additional thrust the second propeller requires to give the flow field generated


texts: Calculate parasite drag coefficient from drag polar

texts:
The drag polar of an electric-powered unmanned aircraft is

$$ C_D = 0.038 + 0.0458 C_L^2 $$

What is the parasite drag coefficient?


texts: Would an accurate weight of a loaded aircraft be helpful?

texts: If a commercial aircraft's actual weight at takeoff is accurately known (instead of being estimated), can this help with use of thrust, optimal altitude, etc and therefore fuel savings, emissions etc.?


texts: Do pilots choose which aircraft to get rated for or is it the employer that decides it?

texts:
How do pilots end up flying a specific plane type? Do they choose what type of plane they want to fly and persevere the goal or do you generally get an ATPL and then get a rating based on what your employers aircraft models are?

Example:

I love turboprops and in particular the ATR42, I get employed, if I'm lucky or good, by an airline that has ATR42/72 mixed with other aircraft in the fleet. Do I have a choice as a pilot or do I have to strictly adhere to the aircraft that my employer assigns me?


texts: How is control of the airplane passed from one pilot to another?

texts: In both the Tenerife accident in 1977 and the Air Florida accident in 1982, the first officer (FO) in the cockpit opposed the decision of the captain to take off. What should the FO do if the captain is determined to do the wrong - possibly even the fatal - thing?


texts: Why are hexa airfoils used on rockets despite having more drag that diamond airfoils?

texts:
I was doing a study on airfoils shape for a rocket. I tested the diamond and the hexagonal airfoil with Missile DatCom, RasAero and the Shock Expansion theory and from my results it seems like the diamond is better (little more lift and noticeable less drag). Looking at other rockets design I found out that many actually uses hex airfoil, but I don't get why. Am I missing something? Any reason for that?

Also like 99% of rocket uses a sweep angle. If I remember correctly, having a sweep angle reduces the Mach number normal to the L.E., so using a sweep angle means that I'll have a subsonic flow normal to the L.E. even if the fligh Mach is supersonic. So, the L.E. should be rounded. Since all these rockets uses thin sharp airfoils, wouldn't the wing work better with no sweep angle?


texts: For large jets, what is the primary means of slowing down after landing?

texts:
I understand that a large(r) commercial jet slows down after landing using the following methods:

Wheel brakes
Reverse thrust
Spoilers/flaps/airbrakes

What is the effectiveness of each compared to the others? What if one of the first 2 fails? Can an airliner usually be stopped without using wheel brakes or without using reverse thrust?

And what if the runway is slick because of rain, snow or ice? Does that change the equation?


texts: What are dimensions of the B-17 propellers?

texts: I'm curious about the aerodynamics of the Boeing B-17 propeller, as the proportions looks perfect for a project I'm working up. Does anyone out there know where to find the specs/dimensions/models for the B-17 prop?


texts: Why can't you have sail-powered airplanes?

texts:
So, sailing boats take the kinetic energy of a crosswind and turn it into thrust by using their sails as lifting surfaces, and the discussion I had in the comment section of this question made me wonder why nobody has ever built any (working) sail-powered airplanes.
Basically, imagine a glider, but with sails on it (maybe on both top and bottom of the aircraft, to avoid imbalances in the center of thrust tipping it over) to catch the crosswind and provide forward thrust. Since these vehicles don't exist, there are presumably problems with them that would prevent them from working.
What are these problems? Do the aerodynamics of the sails interfere with the aerodynamics of the wings or something? Even if sails don't provide enough thrust to get the plane off the ground, that wouldn't be a problem for a glider that can't get off the ground by itself, right?


texts: PT-6 Starting problems - PT6A - 67B, installed on a PC12

texts:
we are having trouble starting our PC12. After introducing fuel at stabilized 13% ng, the engine spools up very slowly - it takes forever to get through 20, 30, 40%ng. We've had several hung starts, and aborted starts.
Battery discharge test is fine - 106% on the first test, and it is a new battery.
Any suggestions for next step trouble shooting? Our mechanic doesn't seem to have a clue.


texts: On a recent trip to an airport, I noticed a large number of Bombardier Dash 8s. I wanted to know - are turboprops less safe than traditional jets like the 737 or A320? For instance, I would imagine they are less forgiving with bird strikes.


texts: What design features or systems help to prevent a hard nose landing?

texts:
Pilots perform perfect manual landings almost all the time with the nose wheel touching down softly and elegantly. When landing an aircraft of any size really more so for the jumbos and super jumbos, this seems like an incredible feat given their weight and the speed at touchdown.

Apart from training, what design features or systems aid the pilot in achieving a soft nose wheel touchdown? Are there any features to help pilots in the event of an accidental abrupt push of the yoke during touchdown?


texts: What is the difference between fuel exhaustion and starvation?

texts: Is there any technical difference between fuel exhaustion and starvation? And what does it mean if a pilot says he has a "fuel shortage"?


texts: Do you have to explain what your emergency is?

texts:
Story Time:

Let's assume, for the sake of the question, that you were piloting a twin engine plane and the right engine, out of the blue, shuts down.

After realizing it you declare emergency, and explain very briefly to the ATC what is your situation at the moment, and after that you start to work out the checklists (I don't know the right order to proceed on a emergency scenario, but i don't think that it's important to this question).

After that you managed well the situation and safely landed the plane.

So here is my question:

At the moment of the emergency you weren't able to explain with details everything that happened to the ATC.

According to FAA, is it required to detail/explain (maybe file some kind of official document) your emergency to some kind of authority?
If you do have to file an explanation, what information do you have to supply?
Also what would happen if they "didn't believe" that situation was an emergency?


texts: Does my PPL need to be checked again when I move to another country?

texts:
If I acquire my PPL in one country and move to another one, is there any procedure to evaluate that PPL and get it in another country?

Did anyone have an experience with that? I'm interested in general rules, if any, and to know what would happen when moving from EU to USA or USA to EU, in particular.

Also, what about renting an airplane in another country? Would someone need to reevaluate my license?


texts: Is a supertransporter considered a different aircraft type than the one it is derived from?

texts:
By supertransporter I mean the SuperGuppy (derived from the Stratocruiser), the B747LCF dreamlifter, the A300-600ST, the airbus beluga XL, and any other aircraft whose role is to transport so large pieces that its cargo bay is way larger than the fuselage of aircraft it is derived from (I don't even know if my short list is exhaustive).

The answers of the question How are evolution and variants of aircraft considered by certification authorities? highlight that variants of an aircraft are considered as simple modification of the first type. In the case of super transporters, I imagine this is the same but:

aerodynamic obviously differs (may be especially relevant for rudder authority and engine out on take off scenario)
pressurization systems may differ (I guess those aircraft are not pressurized as airliners)
structural strength and command transmission are affected (cockpit shift, cabin floor in which cable may run suppressed, ...)

Those modifications are heavy and can affect all flight phases.

Given the Beluga XL (resp. the B747 LCF) is basically an A330 (resp. a B747) with modifications, does it share the same type certificate?


texts: How is passenger baggage transferred, and how does it happen so quickly?

texts: I've always wondered how airlines transfer bags between connecting flights. At a hub, bags must be moved to any number of connecting flights throughout the airport - some with very short connecting times. Seems like sorting them would take a lot of time. How does this process happen?


texts: How do you visually identify aircraft from the ground?

texts:
Are there any good resources that teach you how to identify jetliners from the ground? I'd love to see some great comparative photos of their silhouettes. Books or websites are both ok.

For example, here's a plane that was flying over yesterday en-route to KSFO. I'm guessing it's a 747 or A380, but I can't easily guess from this angle.


texts: What is the ratio of Commercial + ATP pilots with employment as pilots in the US?

texts: Of all certificated commercial/ATP pilots in the US under the age of 65, how many are employed in full-time pilot roles vs commercial/ATP pilots with some other profession than a pilot?


texts: Do large airliners have a short-field landing technique?

texts:
Other than extra braking and reverse thrust, is there a specific short-field landing technique for large jet airliners?

In discussions about the famous landings at St Maarten, it is sometimes said that part of the reason for the low passes is due to the relatively short runway, so the 747s try to land right on the numbers, rather than the usual technique of touching down within the first third of the runway.

Such a procedure is fine in a Cessna, but in a large passenger jet? I have my doubts.


texts: How strictly are language rules adhered to between Pilot and ATC?

texts:
My understanding is that there are general sentence structure rules that must be adhered to when there is contact between Pilot and ATC are well defined, like this.
Are these rules strictly followed in the real world, and is all other conversation fully avoided?

If not, does it happen often enough to be considered while designing an automated ATC response system?

(Based of videos of pilots sharing lighter moments with the ATC on YouTube)


texts: Why was the Bell Boeing V-22 Osprey not worked on more?

texts:
I've recently learned of the Bell Boeing V-22 Osprey and it appears to be a very advanced and useful vehicle. I can instantly think of reasons why the Osprey would be successful such as:

1) It can take off in small places and land in small places unlike planes
2) It can hover
3) It can turn into a plane and fly fast
4) It can pick up things like cars without the need to carry it inside like planes
5) It can easily fly sideways and backwards

So my questions are:

1) Why hasn't the Osprey advanced/been successful. For example how the F-15 went to the F-16 then the F-35 etc.
2) What made Boeing choose to have rotors instead of the faster jet engine?

The only possible reasons I can think of are things such as:

1) Stealth/noise, the Osprey requires large rotors and probably makes double the noise as a helicopter or plane would make
2) Maintenance costs, a helicopter requires more maintenance than a plane, I'd think the Osprey requires more maintenance than a helicopter or plane
3) Cost, the Osprey probably costs more than an average plane or helicopter

Though I'm not sure of the real main reason as surely those reasons can be fixed.


texts: How high does a jet have to be to hear its radio call?

texts:
I am a student pilot and I am learning about radio signals/communication.

I am studying for a test and a practice questions states:

You are flying circuits at a small airport and are flying at 1800ft ASL in the circuit (1000ft AGL) when you hear a radio call from a commercial jet at an airport 123 nautical miles to the south. Roughly how high does this jet need to be so that you can hear his radio call?

The only reference I can think of is that VHF signals can be heard by using a formula of:
Nautical miles = 1.23 * √ height above ground level. The answer would be 10000 ft (AGL)?, but I am not sure if that is the right formula to use or how to figure it out.

Please help.


texts: What is the range of frequencies of vibration in a helicopter due to the main rotor alone?

texts:
Vibration in helicopter can be caused by many different reasons. I am interested to know what is the range of frequencies of vibration due to the main rotor alone?

I understand that it would depend on the helicopter type. So any reference to such analysis would be appreciated.


texts: Why does the chevron-shaped engine suffer losses in thrust performance?

texts:
From here I found out a lot about chevrons on the Boeing 787, but not enough to satisfy why it results in performance loss.

My thinking was originally, if they are "cutting triangular holes" in the "bell cone", then some part of the exhaust will expand sooner than others. (I'm more of a rocket guy myself). Or you could think of it as "adding triangular extensions" to the optimal bell-cone, in which case some parts of the exhaust will expand later than usual. Or you could meet in the middle, which is probably the best way, but will still result in suboptimal expansion.

But I find myself wondering about an even simpler analogy: If sound is wasted energy from an engine (that could have gone into thrust), then reducing sound somehow must mean that otherwise wasted energy has actually gone into thrust production and therefor would boost thrust performance?

So which is it really, and why?


texts: How does an FMS shift after losing all external navaids?

texts:
It's not uncommon for polar flights to lose GPS signal (ionosphere issues due to the high latitudes). But it is not a concern because the typical IRS drift is 650 meters for every hour of flight, and the skies are empty (compared to the Atlantic tracks) in those regions.

Sooner or later GPS will be back, navaids will be within reach, and radar coverage will resume.

Q: Now, what happens when the GPS signal is lost? Does the FMS navigation start to drift from this point on, or does it switch to all the accumulated IRS drifting that's been going on for hours prior?

One way to picture the latter (I guess), is the magenta line on the navigation display to abruptly shift away from the plane-symbol, even if it is just by a mere few nautical miles.

My question applies to the older IRS systems that require stationary alignment, unlike the new GPS-coupled align-in-motion systems found on the 787, etc.


texts: Is there a type of instrument/display that guides pilots along a certain path?

texts: What do you call an instrument that can help a pilot fly along a predetermined flight path (e.g. path thru GPS coordinates), showing them when they stray a little so they can correct? Not a control system, but just a visual feedback display. I want to say I've seen something like it before, that had two panels each with a plane symbol and "reticle", but I would like to know what it is that I'm describing. Thanks


texts: How does the aspect ratio of the vertical stabilizer affect stall speed?

texts:
The higher aspect ratio of a vertical tail surface (higher at least when compared to the fuselage) will allow to make the tail smaller, but causes an earlier stall.
  -Peter Kämpf said so here

How does the vertical tail, and more specifically, the aspect ratio of the vertical tail, impact stall?


texts: I believe the NTSB account, but based on this graph, http://twa800.com/lahr/zoom-climb.htm, why did the flight not stall after the nose separated?


texts: What is purpose of engine pylon airfoils on the Hondajet HA-420?

texts:
The engine pylons on the Hondajet are aerodynamically shaped so as to provide a lift force laterally and outwardly.

Engine pylon as viewed from rear

Engine pylon as viewed from front

Are these for lateral stability or drag reduction or both or other purposes?


texts: What is the most accurate geometric plane for referencing terrestrial flight attitude?

texts:
I have found various definitions for attitude.

Merriam Webster: inclination of the three principal axes of an airplane in flight to the relative wind.
Wikipedia - Attitude Indicator: the orientation of the aircraft relative to Earth's horizon.
In my words, based on my current understanding: the angular orientation of the longitudinal and lateral axes relative to a 2D geometric plane, which is orthogonal to the Earth's average curvature at the point on the surface below the aircraft.

What is the correct reference plane for flight attitude in regards to terrestrial aerodynamic flight?


texts: Which air traffic controller positions are considered most challenging?

texts:
Consider a large ATC facility, where a range of ATC services are provided and each position requires a dedicated person to manage (unlike small airports, where the same guy is ground + tower). Which positions are considered the most demanding, and it would make sense to assign a senior and experienced controller there?

I would imagine, Clearance Delivery is probably the easiest one, then Enroute, Approach / Departure, Ground and finally Tower. What's the training sequence recommended by the authorities for a new controller? After all, assigning a fresh trainee to LAX tower or JFK ground does not sound like a good idea.


texts:
See my other question here for the background context.

Consider this simple plane. I have applied the 4 basic forces: lift, drag, weight, and thrust. My question is, where, precisely, do I apply the lift force?

I've read through this which says it's at a quarter of the chord length. But where does that sit in 3 dimensional space? Most airliners have slightly swept wings. The chord length also changes along the wing. How can I model this mathematically?


texts: Are instrument lights required for night VFR flight in an SLSA?

texts: Our flying club is operating an SLSA that has all the exterior lights as required by FAR 91.205(c).  But don't the instruments that are also required by 91.205(b) need lights as well?


texts: Is the A350 more efficent than the B787?

texts: I have wondered this because the Trent 1000 engines are very similar to the Trent XWB engines on the 787. And if the A350 has better efficiency then why do so many airlines purchase the 787?


texts: How much energy-per-unit-weight is required for a hovercraft to hover?

texts:
I understand that the answer probably differs for different models.  I am only looking for a baseline.
This may be the wrong community to ask about hovercrafts.  If so, I apologize.


texts: Forces that wing attach fittings must transfer to fuselage?

texts:
I just saw the naked wing (it didn't have its wing fabric) of a Weedhopper ultralight and wondered the types of forces that the wing lift struts must transfer to the fuselage, apart from the apparent lift force?

Secondly, in a wire braced wing like the Weedhopper, do lift struts carry the lift load on the span between their attach point and the fuselage or do they carry the lift on the span from the attachment point to the wing tip?


texts:
From and related to: What is the relation between drag and weight?

  Friction drag is not affected by the angle of attack change.
  The [induced] drag will increase with the square of the mass increase.

I have no doubt about that, in fact I was going to post the same answer, the reason I waited is because I could not explain the A320 performance figures using this method.

The drag breakdown for an A320 at FL 370 and M0.78 is:

  7,900 lbf of drag is composed of 4,700 lbf of parasitic drag (...) and 3,200 lbf of induced drag.

Let's consider a 32% weight increase -- from 50 to 66 tonnes. Applying 1.32^2 to the induced drag raises the total drag by 30%.

If we used the FF (fuel flow) as a thrust (also drag) measure -- since at a given FL / IAS / TAS the TSFC shouldn't vary that much when the N1 is ± a few percent --

... we find the ΔFF is 7% at FL 290 and 20% at FL 370. 20% is closer to the 30% thrust/drag estimate. Why is the thrust/drag increase much lower at a lower FL with weight the only variable?


texts: Why are the cabin inner windows so flexible?

texts:
A few days ago I flew on an A321. While pointing to something outside my finger touched the window. It made a crackling sound and felt quit flexible.
I was able to push it at least 5mm without any effort (I didn't wanted to push further because I thought I might break it).

On the way back, I flew on a B737 and the same thing applied on its windows as well.

I'm pretty sure it's that thin because of the weight but is there any other reason for such a thin (and probably fragile) inner glass which could be easily damaged by a passenger by mistake?


texts: What are the failure mode(s) for flying cars in case of power loss?

texts:
There seem to be lots of plans (and even some working prototypes) for various autonomous flying cars and flying taxis.

Most of these seem to be based on vertical take-off using some variety of an electric quad-copter (or something very similar).

Conventional planes can glide in the event of engine failure, and traditional single rotor helicopters can auto-rotate. Both techniques should get the aircraft safely (more or less) down assuming the controls remain effective.

What is supposed to happen with a quad-copter based flying car/taxi if the power fails? I don't think the fixed props on a quad copter can auto-rotate, so how are they supposed to land? Ballistic parachutes? or something I've missed?

UPDATE for clarity (I hope). The media seem to use phrases like flying cars/flying taxis and autonomous aircraft or drones almost interchangeably. I'm talking about aircraft that have no (or minimal) wings (and therefore can't glide) and no capacity for auto-rotation. Here are a few examples...

Now have a look at this final photo, it shows an electric aircraft (a glider) with a battery fire. Being a glider the survival options were relatively simple, the pilot landed ASAP and got out of the aircraft. This doesn't seem to be an option for any of the designs I've pictured above.


texts: Why are crop dusting spray booms not integrated into the wing?

texts:
All crop dusting aircraft seem to have an externally mounted spray boom for distributing their pesticides, I imagine this significantly increases drag & therefor performance.

What gives? why not integrate the spray system into the wing?

I have read that crop dusters spray booms remain short of the wing tip to prevent interaction with the wingtip vortices, perhaps another aerodynamic interaction along the main span of the wing prevents this integration?

thanks for considering my question!


texts: When filing an ICAO flight plan with LPV, is marking GNSS equipment necessary or redundant?

texts: Should equipment 'B' (LPV) and Equipment 'G'(GNSS) both be filed simultaneously in an ICAO flight plan, or does equipment 'B' simply imply GNSS?


texts:
In the recent article Flightradar24 gears up for a new wave of flight tracking I've read about FR24's experimental Wave Glider ADS-B receiver - essentially a self-propelled, solar power buoy as a remote ground station.
What do the radiation patterns of ADS-B transmissions on large airliners tend to look like? In particular, the transmissions that would be received by satellite or surface ADS-B receivers collecting traffic information.
Are there any examples of these radiation patterns published? Are there guidelines, best practices or regulations that apply to the directionality of the radiation?
An example of a general requirement might be EASA's CS-ACNS:

CS-ACNS.D.ELS.060 Antenna installation
(See AMC1 ACNS.ELS.)
(a) The installed antenna(s) has (have) a resulting radiation pattern which is (are) vertically polarised, omnidirectional in the horizontal plane, and has (have) sufficient vertical beam width to ensure proper system operation during normal aircraft manoeuvres.
(b) Antenna(s) is/are located such that the effect on the far field radiation pattern(s) by the aircraft structure are minimised.

which only addresses directions above/below horizontal to the extent that they apply to "normal aircraft maneuvers." There may be more.

Below I've added a similar but different gain pattern as an example of the kind of data I am looking for. However it is the gain pattern for a downwards-looking ADS-B receiving aboard a satellite, showing good reception from below (nadir: $\theta,\phi \approx 0 $). What I am looking for is a similar type plot, but for the radiation from an aircraft.

above: Photo of FR24's ADS-B receiver aboard a Liquid Robotics Wave Glider platform. Photo credit Flightradar24.

above: Example from this paper of an receiver's gain pattern. In this case it is an ADS-B receiving antenna system, aboard a satellite, showing gain optimization looking straight down (nadir).


texts: What are the aerodynamic advantages and disadvantages of the Weltensegler wing?

texts:
What are the aerodynamic advantages and disadvantages of the Weltensegler Wing?

Would this kind of wing configuration come to help for a glider?
Is there any difference between them and gull wings?
What are the aerodynamic advantages of gull wings?


texts: When should a PPL student start learning navigation?

texts:
A big part of the ground syllabus for PPL training is navigation and flight planning. The ground training feeds into practising navigation in-flight and of course eventually to the qualifying cross-country.

What's the best time to start the classroom work on this subject, in the context of training that's spread out over a long period? What are the pros and cons of learning it at different times? If it makes a difference, I'm interested in the situation in the UK for an EASA PPL.


texts: What is the dark spot visible below the cockpit on A-10s?

texts: On most A-10s I have seen, the area under the cockpit is darker than the rest of the plane. Is there a reason for this?


texts: Why only the outboard ("low speed") aileron drops when there is no hydraulic pressure on the 747-8?

texts:
As the title says, why only the outboard ("low speed") aileron drops when there is no hydraulic pressure on the 748?

(Full resolution)


texts: How do planes benefit from flying in formation?

texts:
Large flock of birds when migrating usually fly in an arrow formation, which helps the birds to save energy while flying the same distance as compared to a situation when the birds are not in a group.

What is the physics behind this?
What is the significance of the specific flying formation?
Can this be applied on airplanes (given the fact that anything analogous to engine exhaust is not present in birds)?


texts: What is the height of the Boeing 747-8 landing gear?

texts: I can never find any information about the height of the landing gear on any airliner(can you put it into feet and inches).And Is the height of the 747-8 landing gear around the same height as the 737 or airbus a320.


texts:
Can anyone identify the fighter here in this picture taken from a Dornier-do17?

From: https://stukablr.tumblr.com/post/145040185970/a-pic-took-it-from-a-donier-do17-a-hurricane


texts: 6 Series Airfoils were developed to enhance the laminar flow region over the airfoil. But, the Reynolds number at which planes fly are high for the flow to be Laminar. Then what's point of introducing 6 series airfoils when laminar flow is not possible?


texts: Considering a piston engined aircraft, what resistance pressure would be generated within its engine bay against its cooling intake?

texts:
Consider a piston engine with all its coolers and components within an aircraft engine bay. To cool this engine, cooling intakes are positioned facing the direction of flight. Now, the condition at the inlet surface need not reflect the flight conditions exactly, one reason for this would be since the resistance pressure from within the engine bay would influence the conditions at the inlet itself.

The question is specific to this resistance pressure as a first approximate at least. I know there are a variaty of other reasons as to why the conditions at the inlet surface would change (e.g pressure distribution at location of intake position, inlet type, etc...) but those aren't a concern here yet.

A good answer to this based on actual data, or statistical data or even experience would be greatly appreciated. Sources as to where one may find the answers to this would also be much welcomed. Thanks in advance!


texts: When ATC uses distances, are they using nautical miles or statute miles?

texts:
"Skyhawk 872ND, airport at your 12 o'clock in 15 miles."

"Baron 981K, traffic, 2 o'clock 5 miles, opposite direction, a Piper southbound, 1000 feet below you."

Does ATC use nautical miles or statute miles?


texts: Why do some multi-engine aircraft have accelerate-go distance in their performance charts and some don’t?

texts: I'm curious about why some airplanes have accelerate-stop distance (ASD) and accelerate-go distance (AGD) in their performance charts and some don’t include that. Does anyone know why?


texts: What determines spanwise placement of spoilers for roll control?

texts:
Specific application of spoilers was discussed in What is the benefit of spoilerons compared to ailerons? As I remember it, 40yrs ago gliders had spoilers close to the wing tips - perhaps slightly inboard of the normal aileron position.

Current aircraft design places them mid-wing or even next to the wing root. What design principles favor a particular span-wise location.

To be specific; I am interested in roll control not drag.


texts: What happen to schedule flight when airport close for undertermined duration?

texts:
very similar to What happens to incoming flights when the airport shuts down

In the event that an airport shuts down for undetermined period, flights that already airborne would be divert to other nearby airports. What about planes those are still on the ground? Would they proceed to takeoff to land at a diversion or would they simply cancel the flights?
What about next day if the destination airport still close? Would they cancel all flights until airport reopen?


texts: Where does the final approach begin if the glide slope is intercepted at an altitude above that depicted on the approach chart?

texts:
The final approach segment for an approach with vertical guidance or a
  precision approach begins where the glideslope/glidepath intercepts
  the minimum glideslope/glipdepath intercept altitude shown on the
  approach chart. If ATC authorizes a lower intercept altitude, the
  final approach segment begins upon glideslope/glidepath interception
  at that altitude.

(FAA IPH, p. 4-53)

Does this paragraph imply that the FAF(FAP) for a precision approach fix (point) begins at the minimum glideslope intercept altitude when you have intercepted the glideslope at an altitude above that?

I always have thought the FAF for a precision approach begins wherever the glideslope is intercepted regardless of a glideslope interception altitude. Have I been getting it wrong all this time?

This question doesn't answer what I'm asking. I'm not asking where the FAF generally begins on a precision approach; I know where it begins and I've cited it above. My question is whether the FAF begins at the interception point even when the glide slope is intercepted at an altitude above the minimum interception altitude on the chart. The definition above from the IPH clearly says the final approach fix is the interception altitude when it's intercepted at an altitude below the minimum interception altitude but is silent on where the FAF begins if it's intercepted at an altitude above the minimum interception altitude.


texts: Why is there a GPS/RNAV waypoint co-located with a VOR?

texts: There is an RNAV waypoint named STYCK co-located at what appears to be the exact location of the LOA VOR (coordinates match precisely as well). Why would the creation of a waypoint be necessary if IFR GPS/RNAV units/databases can take both VOR names and waypoints? Why not just use the VOR name that has existed there for over 50 years? Such a thing is regularly done in IFR SIDs and STARs when loading them into a GPS/FMS.


texts: What are hydraulically powered and electrically controlled actuators?

texts:
I thought that the actuators are hydraulically controlled when the hydraulic fluid changes their position, but some aircraft (Bombardier, for example) has hydraulically powered and electrically controlled actuators.

What does electrically controlled means?
How does hydraulics power the actuator?


texts: Why are military drones shaped so strangely?

texts:
Military drones, such as the Predator drone or the Global Hawk, tend to have a weird shape with a whale-like head, and engines concentrated at the back. The wings tend to be of very high aspect ratio, and v-shaped tails seem to be popular:

Why aren't there, say, Cessna-shaped drones? If Cessna 172s work fine for human pilots, why not for computer pilots? The Cessna 172's low speed and stability also seems like a good asset for military recon drones.