texts: Why are commercial flights not (publicly) trackable in some locations?

texts:
Flying BA15 from London to Sydney, I noticed that the flight is not tracked over Turkmenistan and Afghanistan, except for a short ping.

Is this for security reasons? Do planes disable their ADS-B, or is the data somehow restricted? Since position tracking is a safety feature, is this regulated or an airline decision?


texts: Does the captain always control thrust on takeoff?

texts:
I just read an article about a day in the life of a pilot and it states "The Captain always controls the thrust in the unlikely event that the take-off needs to be aborted for safety reasons." Is this correct?

It was always my understanding that the roles of PF and PNF can be alternated between the captain and first officer, and controlling the thrust would fall into one role or the other. I also recall seeing videos of the flight engineer pushing the throttles.

If the take-off needs to be aborted, can't the captain just command the FO to "abort" or take control by saying "I have control" or similar?

Finally, will pulling back the throttles be enough to abort takeoff safely without braking? Surely it would just cause more problems?


texts: What prevents aircraft with a tailcone APU from using tail-mounted airbrakes?

texts:
The BAe 146 and Fokker F-28, which are virtually alone among jetliners in lacking thrust reversers, compensate by using large, tail-mounted airbrakes to help slow the aircraft during descent and landing:

(Image by Adrian Pingstone at Wikimedia Commons.)

According to this answer to a previous question about why we don’t see this on more (and bigger) jetliners, the BAe 146 and F-28 are only able to use tail-mounted airbrakes because, unlike most jetliners, they lack an APU in the tailcone:

  ...Air brakes such as the RJ100 have only upsides, since they influence drag only, not lift. They're not used everywhere because the bit of fuselage where they are mounted usually houses an APU.

(Emphasis added.)

But I don’t see why having an APU in the tailcone would preclude the use of tail-mounted airbrakes; the APU is situated in the middle of the tailcone and exhausts out the tip of the tail,1 while tail-mounted airbrakes are mounted on the sides of the tail and deploy to the left and right:

(Image by dtom_cro at Photobucket.)

As such, having a tailcone APU shouldn’t necessarily preclude having airbrakes on the sides of the tail; in the 146, the space between the airbrakes is basically empty, with only a light truss supporting the rear collision beacon, but it'd be easy to have something more substantial - such as, for instance, an APU-and-other-machinery-housing structure - in between the petals:

What am I missing here?

1: As @ymb1 points out in their comment, the BAe 146 does have an APU, but its APU obviously does not exhaust out the tip of the tail; that statement regarding APU exhaust placement refers to its location in the vast majority of jetliners in general.2

2: That last statement obviously does not apply for jetliners where that real estate is taken up by a full-blown engine (727, Trident, Tu-154, Yak-40, L-1011, Yak-42, etc.).


texts: Can small planes see lights on the ground?

texts: I live about 5 miles from a small airport. At night, during rain or snow storms when I imagine there would be poor visibility, I always turn our outside house lights on, in case they could possibly help a little plane in distress. Am I crazy?


texts: Why does the U.S. keep thousands of retired aircraft in storage?

texts:
A view of Davis-Monthan AFB shows thousands of retired aircraft sitting in the desert.

They go through great lengths to preserve them, even sealing them with an opaque white, hi-tech vinyl plastic compound called "spraylat."

Such an enormous stash of aircraft makes me wonder what they're being kept for. I'm sure there are a few uses for some of them but certainly not all of them. There can't be a big demand for spare parts from obsolete planes. It seems like they would want to scrap them.

Are they being kept in case there is some sort of all-out war and they need cobble together a bunch of F-4's and C-141's to support the air force? Would that even be feasible?

Does it somehow cost more to scrap them than the materials are worth?

Why are they keeping so many retired planes?

Photos retrieved from airplaneboneyards.com


texts: I've read in PHAK that slats reduce stall speed, but in what way? Is it because of the increase in surface area?


texts: Will wingtip drag always be more for a smaller aircraft, keeping constant aspect ratio?

texts:
Sometime ago, I came across an article (I couldn't find it) which stated that wingtip drag was only related to absolute wingspan. That is, for the same wingspan and lift force, varying the chord will not change the wingtip drag. I have also seen an answer on Aviation SE where this appears to be mathematically proven.
So my question is; am I correct in stating that , for a given lift force, wingtip drag only depends on wingspan, not chord, and thus that smaller aircraft are doomed to have more wingtip drag than larger ones?


texts: Why are aircraft callsigns pronounced over the radio in a non-phonetic alphabet way?

texts: Why is it numbers are not always pronounced in a phonetic way? For example a flight number of 2390 is pronounced "twenty-three ninety" instead of "two three niner zero"


texts: Can Ospreys land without running engines?

texts:
I just have seen a video of a demonstration of an Osprey V-22. While this is an impressive aircraft I wonder whether this might land with failing engines (with the large "propellers" probably hinder proper gliding).

What would a pilot do in the following cases:

one engine failed
both engines failed
tilt mechanism stuck


texts: Is it more efficient to have many or a few rotors?

texts: Wouldn't it be smarter to design VTOL rotorcraft with many smaller rotors than one big rotor? With more rotors you have more redundancy and smaller blade velocity (and perhaps better stabilisation) thus leading to a safer more reliable system. It seems like the problem with lots of rotors is that you lose all efficiency. I don't get this though. If a rotor prop produces x thrust at y efficiency, couldn't this be simply scaled up to produce the same thrust and efficiency ratio?


texts: How the Log Periodic Dipole Antenna of Localiser help in varying modulation depth?

texts:
Here Albert Helfrick speaks about 40% modulation depth for each tone in a localiser radio signal. However latest manuals of ILS manufacturers and google source speaks about 20% modulation depth, not 40%. Albert also says that modulation depth becomes 20% at the centreline of runway.

My question is whether Albert is correct or manufacturers like NORMARC, Thales and SELEX are correct? If Albert is correct then how does 16,20,24
element log periodic dipole array help in achieving this modulation depth variation?

I would appreciate if someone with proper explanation comes up. And this question is not duplicate so please do not confuse it with other modulation varying behaviour of questions asked on this forum.


texts: Why does flight duration differ for the same flight?

texts: I was checking the flight duration between two places over a 2-3 month period. The flight duration for the same flight is different for different months. For example, some days the flight takes 13 hrs 10 minutes and some other days it's 12 hrs over the same distance. How does this happen? Moreover, this data is available long before the departure of the flight; I am curious to know the reason. What are the factors that decide this?


texts: Is there a list of airports with Category 3 ILS systems?

texts: Is there a list of airports with category 3 Instrument Landing Systems?


texts: Why am I seeing extremely high L/D ratio of (e.g. L/D = 90) in my 2D airfoil analysis?

texts:
Can anyone explain/justify why, using the 'Theory of Wing Sections' by ABBOTT the lift/drag ratios seem so high. For example, I'm doing an analysis of the NACA0012 airfoil and using their experimental data on pg462/463 at 8 degrees CL is roughly 0.9 and CD is roughly 0.001 giving a lift/drag ratio of 90. This seems incredibly high since as far as I'm aware lift/drag ratios go up to 70 to 75 practically from answers I've seen on here. My problem is that my CFD analysis also gives these high lift/drag ratios but I just didn't think it was possible.
Thanks in advance to anyone who can help!


texts: Is a CFI's 1st-time pass-rate based on the student or the instructor's first attempt?

texts:
This question doesn't apply to anything I have done personally, and beyond word-of-mouth, I have no references about this happening.
Some people claim that if an instructor endorses a student and they fail an FAA check ride and then a different instructor endorses the same student for the re-take and then the student passes the re-take, that the instructor who endorsed the re-take may count this on his or her record as a first-time pass since the student passed on the first attempt for that instructor's endorsement.
The intended benefit of recording this would be utilizing it for CFI renewals and gold-seal CFI applications.
Is this a practice that is considered to be acceptable to the FAA?


texts: Could an airliner exceed Mach 1 in a zero-G power dive and safely recover?

texts:
(I looked for duplicates. I really did.)
Being as it is that "safety" and this are mutually exclusive:
I am stupid. I take a cruising A320, apply TOGA power, and push zero Gs until I exceed Mach 1. How do I get out of this in one piece? And how much faster can I go before I need to start this process of getting out in one piece?


texts: What operation is this aircraft performing?

texts:
While reading Wikipedia about Ust-Kut Airport, I've run into the following picture:

I'd like to know which operation is depicted here?
This doesn't seems to be a take-off, as per my very limited knowledge. It is by far landing. If I am correct then how it is possible that a landing plane, at this altitude, still doesn't have its gear down?


texts: For a 180 degree turn after takeoff, what is the normal turn radius for the A320 and 737?

texts: I'm looking for some rule-of-thumb guidance on this matter. It relates to route 4, the westerly take off from London Gatwick (LGW).


texts: How and why can multiple people control the Boeing B-29?

texts:
I am making a down-to-the-1/128th-inch (literally, to the 1/128th inch) model of the Boeing B-29 Superfortress in SketchUp. Starting from zero, I had to make the entire plane up, and to be honest it looks exactly like the real thing at this point. I went down to copying every detail in even the dials and switches and levers, and realized something.
I saw that the pilot can control each of the 4 engines independently. Now, that isn't exactly the problem. The problem, is that the Pilot, "Second Pilot", and Flight Engineer can all control each of the 4 engines. And I can't figure out how that's supposed to work! I mean, can the flight engineer just turn up the throttle whenever? But what if the Pilot is going to speed up so that he/she can reach a higher altitude, but the flight engineer doesn't know that and so he turns the throttle down to decrease engine heat because the cowl flaps are at max degrees for stable flight?
Then there's the issue: If the flight engineer turns the throttle down at the same time that the pilot turns it up, what will the engines do? And I doubt the pilot would speak his every move to the "Second Pilot" and the Flight Engineer to prevent a mix-up. So, does the Flight engineer have to literally request permission and state his/her reasoning to the Pilot before changing the throttle?
And then I thought some more, and realized that the "Second Pilot" also has a "steering wheel", which I know for a fact that other co-pilots have in other planes, but I never knew why. The Pilot can handle the plane's steering by himself/herself, can't they? And even if they couldn't, giving the "Second Pilot" a steering wheel too... well, I can't see how that fixes anything. And if the "Second Pilot" turns the steering wheel at the same time that the pilot does, what does the plane do?
Same thing for the pedals I realized that the Pilot and "Second Pilot" both have. It makes no sense. I get that the "Second Pilot" could take control of the plane if needed because of these duplicate control instruments, but what would happen if they were (accidentally) used a the same time as another? And I also don't get why the Flight Engineer would need to be able to change the throttle. The Flight Engineer literally sits in the opposite direction of the front windows, so it isn't like Boeing wanted the Flight Engineer to be able to fly the plane.
Any suggestions would be very helpful. And, sorry about the gigantic question.


texts:
How many C172 models there are out there and what are the differences between them?

Which models have these "modern" (newer) instruments panel design like this one:

versus:


texts: How can the concept of "intercept geometry" be explained in simple terms?

texts: Can someone expand a bit for the layman with emphasis on Intercept geometry the following image depicting the envelope of a SA-2 missile against a moving Target.


texts: How much damage could a landing gear malfunction do?

texts: How much damage could a total landing gear malfunction do to an airliner? Could the runway wear a hole through the plane?


texts: Where can I get information about the FAA "restricted like" license to fly a N aircraft in Italy / Europe?

texts: I have recently bought a N-REG C172 in Italy since 2008 and in fact I have been told by the Italian NAA that my EASA License will be valid limited for flights in Italy. I understand if I wish to fly in other EU countries I should apply for a FAA "Restricted like" License which I can obtain symply by giving a short english language check in recognized FAA offices in Italy. Any Idea about this "restricted" option? Whom should I ask to get more info?


texts: Why is engine #1 still used when taxiing with one engine?

texts:
According to the answer in this post Taxiing with one engine: Is engine #1 always used or do they switch? Engine #1 is used because it pressurizes the green HYD system which powers the Nose Wheel Steering. I found that, in latest model of A320 and A321, NWS is driven by yellow HYD system that is pressurised by engine #2. However, pilots still use only engine #1 if they want to taxi with one engine running.
Is there other reason for using engine #1?

  Source: Airbus AMM


texts: Has the United States Air Force used Contra-rotating Propeller Aircraft?

texts:
I recently saw a picture of a Russian Bear(TU-95) intercepting one of our(US) military aircraft over the Pacific Ocean.

Many years ago, when I flew in reconnaissance aircraft, we were frequently intercepted by Bears which surprisingly flew at 500+ mph airspeed.

Yet no US Military Aircraft uses contra-rotating props(to my knowledge).
Why is that?


texts: Why would a pilot's armrest be a no-go item?

texts:
From the end of issue #216 (June 1997) of Callback:

  Another First Officer also learned too late the importance of consulting the MEL before take-off.

    Inbound equipment arrived late. About 5 minutes before pushback time, I discovered that my right armrest was stuck in the UP position. I attempted to free it, but no luck. I contacted maintenance and asked them to bring something to lubricate the mechanism. A mechanic did so, but to no avail. We figured we could just go with it in the UP position. It did not occur to us to look it up in the MEL, as it did not seem to be a safety-of-flight item.

    Upon our arrival, we were told that the armrest is a no-go item. The continuing flight was cancelled due to this fact, since no spare seat or replacement part was immediately available. The Captain and I were both amazed that something as simple and innocuous as an armrest would be considered a no-go item. In the future, I will check the MEL for any item, no matter how seemingly insignificant.

Why would a pilot's armrest stuck in the up position be a danger serious enough to require grounding the aircraft?  One would think, like the aforequoted pilot did, that it would be, at worst, a minor inconvenience, and certainly not a safety-of-flight issue...


texts: Would diesel (Jet A) cause less pollution than other fuels?

texts: Has any research been done on pollution from a aircraft using diesel (Jet A) vs other standard aircraft fuels? Is there a push to use diesel fuels in GA as a viable alternative and if so why or why not? (Ignoring the consideration of the non-availability of Jet A at most GA airports.) Would diesel-powered GA aircraft be considered the "future of green GA flying" or are other technologies such as electric propulsion more likely?


texts: Where does it say that type certificates are required?

texts:
I am doing research and looking for a regulation (from FAA, Transport Canada, ICAO or anywhere else) that explicitly states that a type certificate is required for aeronautical products (aircraft, aircraft engines, aircraft propellors). I have looked around on google and at the CARs and FARs but haven't found it yet.

Can anyone help me find a specific reference to this regulation?


texts:
How much power from a GPU would a jet, say a Boeing 737, require when boarding passengers or just sat idle on the air bridge?

I’m guessing the Aircraft would only consume the full 90kVA ground power rating when starting the aircraft’s APU?

Thanks,

Chris


texts: How far can a Super Hornet fly at max supersonic speed in a clean configuration?

texts: How far can a Super Hornet fly at its top (supersonic) speed, assuming it's in a clean configuration, i.e. no external tanks and no ordnance?


texts: Does huge rotating AWACS radar affect flight characteristics?

texts:
I would think that having a huge mass spinning around should produce massive gyroscopic forces when turning or pitching.
There must be some clever way of minimising or eliminating the effects... How is it done?

(An example of the sort of thing I am talking about)


texts: Aerion together with Lockheed Martin is building the AS2 supersonic jet. This is the most realistic SS business jet project of all time. But what do they mean by SNLF technology which claims to reduce drag? And how is it better than the delta wing which they claim is inferior.


texts: What is the feasibility of converting an F-22 to carrier use?

texts: I read that the Navy originally considered to use the ATF(Advanced Tactical Fighter) Programme aircraft (Now known as the F-22) as carrier aircraft but declined to do so when it came out. How feasible is it now to convert an F-22 to carrier use? (I kind of want to know because it is a better plane than the F-35 but is not used on carriers even though it was originally planed for)


texts: How does gross weight affect the Minimum Controllable Airspeed (Vmc)?

texts:
I am about to get my MEL added to my CFI, and I cannot get my head around the multiple explanations for how gross weight affects Vmc.
The accepted answer is that The higher the gross weight, the lower is the Vmc.
I have been proffered two contradictory explanations, from both internet articles, manufacturer documents, and other CFIs, both of which seem to me (I have an MSME masters degree in Aero) to be flawed.

That because the aircraft is slightly banked into the direction of the good engine, the horizontal component of Lift (HCL) opposes the yaw from the rudder, thus allowing the aircraft to slow to a lower airspeed before full rudder authority is required to counteract the yaw from the operating engine.
This is wrong, because if you're in a bank, the HCL (by definition, it is HORIZONTAL!), is no longer lined up with the lateral axis of the aircraft. It is misaligned by exactly the bank angle, so, although there is a component of the HCL opposing the yaw force from the rudder, there is an exactly equal and compensating component of the Vertical Component of Lift (VCL) that will be augmenting the Yaw force.  This argument is bogus.

I mean if you think about it simpler, the Lift vector is always, ALWAYS, perpendicular to the wings, so that any effect of Lift along the lateral axis (parallel with yaw forces), must necessarily be zero.
The fact that is not aligned with the earth horizon is irrelevant.

The other rationale I have been presented with is that as the gross weight increases, the resistance to motion (Engineers would call this rotational inertia) increases, and makes the aircraft more stable. This is true, but it is an argument about dynamic stability, not about static stability. In other words, this affects the aircrafts resistance to changes in yaw/sideslip angle. Vmc is about static stability, i.e., at what airspeed does the aircraft, in a static, (unchanging) zero sideslip angle, require full rudder defection to hold the aircraft (STATICALLY) at that zero sideslip angle against all the yaw forces being produced by all the factors resulting from Asymmetric thrust?
So this argument or rationale also seems to be incorrect to me.

Where is the flaw in this reasoning?
By the way, the only effect of Gross weight on Vmc that I can think of is the obvious one, The higher the gross weight, the greater the Angle of Attack required to hold 1 G (Level flight), and obviously, both P-Factor and adverse yaw increases with AOA. So the higher the Gross weight, the greater the P-Factor, and the greater the yaw-induced aerodynamic effects of the asymmetric thrust. So, if this logic is correct, Higher Gross weight means Higher Vmc, not Lower.


texts: What type of supersonic intake does the Dassault Rafale fighter jet have?

texts:
What type of supersonic intake does the Dassault Rafale use? Is it a Pitot Intake? It cannot be a Ramp Intake, nor can it be a Spike Intake / Cone Intake, and it does not seem as a Diverterless Supersonic Inlet either.
Are there any explanations for the half-circular shape of the two intakes?

Sources for supersonic intake types: NASA Website, Aviation.SE Answers 1 and 2, Lockheed Martin CODE ONE Magazine


texts: How is ATC handed for private rural airstrips?

texts: In rural Australia there are farms that have private airstrips. My question is when an aircraft wishes to land at such a strip (for example a flying doctor) who handles the landing aspects of ATC.  Things such as reporting on wind speed and direction, air pressure, ensuring that the strip is clear, advising on glide slope?


texts: What is the purpose for two nitrogen charged chambers in an oleo strut?

texts:
What is the purpose of a twin nitrogen charged chambers oleo, such as the one illustrated below? Why is it used and what are the advantages compared to a conventional mono-nitrogen chamber?
Training manual describes its operation as follow:

"Compression of the strut forces hydraulic fluid through the restrictor, thus pressurizing the nitrogen in the upper chambers and thereby absorbing landing shock loads. A flutter plate in the restrictor assembly permits an unrestricted flow through its controlling orifices during compression, however, flow is restricted during subsequent extension, thus eliminating any tendency to bounce during recoil."

While I understand the operation, it is not clear why this design solution was used.


texts:
I fly occasionally  on a pretty short route on a turboprop (DHC-8). When the airplane descends for landing, I can look through the window and see the ground below getting closer over time. However I can't really tell what the pilots do to achieve that. I know that turns make you lose altitude, but it's very clear to me when the airplane makes a turn, so let's count that one out. So we're basically left with:

Slight nose-down attitude
Reduction of engine power
Combination of both

The reason I'm asking this is that during descent I do get this sensation of going down. However, during that time I cannot really see what the pilot did to achieve it. The nose-down attitude might be too minor for me to actually notice (I do not notice a slight nose-up cruising attitude to be honest). I hear a slight reduction in engine power a few times during a descent, but the feeling of going down and the audible noise reduction are separated in time. Is it that it takes time for an airplane to reduce speed (and as a result, descend) when you reduce engine power?

One additional question: I guess that with all the electronics in the cockpit pilots just set a target altitude or rate of descent, and then the airplane systems apply the correct measures to achieve this. How does the airplane know how much to reduce engine power and/or pitch to achieve this exact rate of descent?


texts: What profile will a Boeing 737 NG follow after pushing the ALT INTV button?

texts: If one uses the ALT INTV button during a Climb or Descent in the Boeing 737 NG on the MCP, what profile (Speed/Path) will the AP follow in such a climb and/or descent? Is it the same as programmed in the CLB and DES pages of the FMC?


texts: When/how to set the inbound or outbound course when intercepting a VOR for a DME hold?

texts:
I have question for holding pattern.

As I know, when I do DME holding I have to intercept VOR radial and decide entry.

However, when I do this I am so confused and do not know how I can select inbound or outbound course.

For example, One instruction is [Hold SE 325R ABC VOR 13 DME Left]

In this case, my instructor says "try to intercept outbound course 145 and make a holding."

However, another instruction is [Hold NW 330R ABC VOR 12 DME]

In this case, my instructor says "set inbound course 150 and make a holding."

In both cases, the position of aircraft was NW from the ABC VOR, and my heading was 150 and distance was almost 18 DME from the ABC VOR.

This is what I confuse that first instruction was setting outbound, but second instruction was setting inbound course for intercepting the radial.

Could you let me know how I can figure out when I set inbound course or outbound course for intercept one for DME holding?

*I use G1000 which has HSI.

Thank you for your work and time!


texts: How are there some Victor airways that exceed the service area of the VORs they are identified by?

texts:
As you can see here, V267 has a length of 149nm, is defined by the Craig VOR (CRG) and the Dublin VOR (DBN) and has a MEA of 3000. According to the AIM, the Service volumes of VORs never reach more then 40nm underneath 14,500ft.

Yes, the Craig VOR or rather VORTAC is described to have the Standart High Altitude Service Volume in the A/FD, but at the MEA, which should also guarantee reception of the navaids in use, the range is still only 40nm. A route at that altitude between those two navaids should only be <80nm, so how can it be 149nm?


texts: Where can I find information about Boeing delivery history?

texts: Where can I find the records of which airplane model and creation number was delivered to which airline in which year for Boeing (Like B737-300 number 32 was delivered to Lufthansa in 1980)?


texts: What is the purpose of the 787 engines extending on landing?

texts: As seen about 53 seconds into this video of the Qantas Dreamliner landing, the engine housings seem to extend upon landing. What specifically is the purpose of this? To balance? To help with air flow?


texts: Would the "AOA Disagree" light be the only way 737 MAX pilots could detect malfunctioning AoA sensors?

texts: Or would there be other warnings on the PFDs?


texts: How can a helicopter show up at 29000ft, 547kts at Flightradar24?

texts:
Today I observed a strange flight on Flightradar24, a helicopter departing HAM and traveling at altitudes up to 29000ft and speeds up to 547kts which seems to be way beyond the specifications of a helicopter.1

The altitude and speed were quite constant on this level between Hamburg (ATD 16:15) and Frankfurt (about 500km from Hamburg, after 30 minutes flight) and then it began descending and slowing down.

The details in normal resolution for better readability:

About 17:00 the symbol didn't move anymore and the helicopter was now down on 2875ft and 177kts near FKB (Karlsruhe Baden-Baden) and then disappeared.

I checked the registration and is indeed the Agosta Westland AW139 shown on the picture.

Does anyone have an idea how this could be. Usually, the data on Flightradar seems to be reliable, but a helicopter at 547kts seems odd.

1. According to Wikipedia the Agosta Westland AW139 can travel up to 306km/h (165kts) and has a service ceiling of 20000ft.

edit: speed was 547kts, not 247, added image with details.


texts: PA/APV Glidepath Descent and Obstacle Clearance Slope's lowest point determination

texts:
I am studying the US Terminal Instrument Procedures manual (TERPS) and as I was skimming through the guidelines about Sloping Obstacle Clearance Surface, I came across the image below from section 2-1-4 (the red circle remark is mine):

The problem is, I can not understand how the lowest point of the OCS, which I have marked with the red circle, is determined. It seems to be a point close to Departure End of Runway (DER), but where exactly?

The only things TERPS states is:

  Descending on a PA/APV glidepath. The obstacle evaluation method for descent on a glidepath is the application of a descending OCS below the glidepath. The vertical distance between the glidepath and the OCS is the ROC; thus ROC = (glidepath height) - (OCS height). The ROC decreases with distance from the precise final approach fix (PFAF) as the OCS and glidepath are converging towards the landing surface (see figure 2-1-3). The OCS slope and glidepath angle (GPA) values are interdependent:  OCS Slope = 102/GPA; or GPA = 102/OCS slope.

Could someone point me in the right direction?

EDIT: What I mean is, why (and how do I calculate the extra distance) does the first image apply, rather than the second?


texts: What's the purpose of partial autopilot disengagement after applying certain force to the control wheel?

texts:
Aeroflot Flight 593 crashed after the autopilot was partially disabled by applying certain force to the control wheel but the only function which was disabled was controlling the ailerons. This partial disengagement went unnoticed for a number of reasons.

I'm reviewing the official accident report (text is in Russian, linked to from the Wikipedia article) and here're my findings from there so far.

The flight manual (cited in the report) is claimed to say that manipulating the control wheel to contradict the autopilot is definitely abnormal and should be avoided. The mechanism for overriding the autopilot is a safety device that engages outside normal operational conditions.

So it looks like there some functionality that allows to override the autopilot and partially disconnect it (so that only ailerons are no longer controlled) and it is claimed to be a safety measure.

What's the purpose of this functionality?


texts: Are gyroscopic effects of tail rotor noticeable with hover spot turns?

texts:
I have a question of the book  "The foundations of helicopter flight" by Simon Newman.

The question is from page 186:

1) How can we feel gyroscopic effect of tail rotor with hover spot turns?


texts: How does pulling back provide better steering during rollout for light GA planes?

texts:
I had requested clarification on an answer to the question, How do I keep a C172 straight on the centerline during landing/rollout? I did not comprehend how pulling back after touch down provides better steering, the reply to my comment was:

The nose gear won't be off the ground, it will just have less pressure/force on it. The oleo strut won't be compressed, and the wheel will have an easier time turning side-to-side smoothly.

But,

Isn't an uncompressed strut (or lightly compressed) limit/lock the steering because of the nose gear centering cam mating?

AFAIK, at least for cars, better steering happens when the front axle is loaded more, whether mechanically or aerodynamically (front-end downforce).

In jet-liners, pushing forward on the control column after landing (or during takeoff roll till about 80 knots) to firmly stick the nose gear is in many SOPs for better control (type dependent; degree of pushing varies). Boeing 777 example:

On touchdown, take positive action to lower the nose gear to the runway and maintain moderate forward pressure on the control column to assist in directional control.

So what am I missing? I don't presume to know more than the above 3 points, after all suspension engineering is not an easy field (with the big shots working for the big racing teams).
Let's limit the scope to light GA planes (in tricycle configuration, of course).
I'm not questioning the validity of the technique, rather inquiring about the physics involved, perhaps there's more to it than the strut?


texts: How do I find the three factors of the hinge moment coefficient?

texts: How do I find the three factors $c_{h0}$, $c_{h\alpha}$ and $c_{h\eta}$?


texts: Why should lower limit of a Control Area (above 3000 ft) coincide with a VFR cruising level?

texts:
In ICAO Annex 11 it is recommended:

When the lower limit of a Control Area is above 900 m (3000 ft) MSL it should coincide with a VFR cruising level

Why should it coincide with a VFR cruising level?


texts: Why were the first airplanes "backwards"?

texts:
In the question Is the location of an aircraft spoiler really that vital? the accepted answer states "Surfaces behind the CoG act as stabilisers, keeping the nose pointing forward. An aeroplane has vertical and horizontal tail surfaces at the back just for this purpose."

I agree that this seems straightforward, to a layman (me). So why then were so many of the first aircraft built 'backwards'. Taking a look at the Wright Flyer

Image (C) Bay Images

as an example. There are many other examples from the earliest days of aviation. Why did many put the elevators up front, thereby destabilizing the whole thing?


texts: Selecting radials for radial interception

texts:
I’m a beginner in intrument flying so sorry for my ignorance. Few months ago I was doing BIR training and with my CFI we were intercepting radials, we were doing that on HSI (Garmin G500).
He told me that If I want to intercept radial inbound I should set the tail of the needle to the desired inbound radial and if I want to intercept radial outbound I should set the head of the needle to the the desired outbound radial.
My question - is this way of setting desired radials correct? Because I read somewhere that we always should set the head of the needle to the course that we mean to fly, no matter if it is outbound or inbound - to avoid reverse sensing.
So if I want to intercept and fly radial outbound 180 I should set head of the needle of my HSI on 180 and if I want to intercept and fly radial 240 inbound I should set the head of the needle of my HSI on 240. Now I'm confused, please help me out.


texts: Is it allowed / legal to produce a Type Rating CBT without the manufacturer's permission?

texts:
Pelesys, Navcon, Flyco, CPAT Global - just to name a few companies - all provide and sell various aircraft Computer Based Training Programs.

Is it allowed / legal to program and sell products that inform and teach aircraft systems and operating procedures without permission from the aircraft manufacturer? How do they get the approval (if there is any approval required)?


texts: What is this 'runway number' automatic readout system on a flight deck?

texts:
I was watching this flight-deck video (starts at 11:13) of a Turkish Airlines Boeing take off from Istanbul and just as they accelerate on the take off roll there seems to be an automatic voice in the background reading out the runway name, "Runway 35 Right".

Is this a standard safety feature? Never heard it before. I've only heard the ATC give the clearance manually.

Is it an aircraft feature or an airport system or a combination? Is it meant to prevent incidents where pilots line up on a parallel taxiway / runway?


texts: Where can I find airport diagrams for the Philippines?

texts:
I would like to have airport map, just like the one that pilots can see when they are taxiing. Is it possible to get such a map, even if you are not a pilot? Perhaps there are applications which a person can use to simulate taxiing on specific runways?
I am interested in Manila airport (MNL) and Mactan-Cebu airport (CEB).
Something like this:


texts: In normal condition, is the Airbus A320 APU fuel supplied by the main engine boost pump only?

texts:
I have a question relating to APU fuel system.
As said in material, there are 2 system supplying fuel for APU to operate. 1st one is primary and 2nd one is secondary.

In the 1st system or low pressure system, there is an APU fuel boost pump locating in LH main fuel tank. Its said that this boost pump is used in starting process or in condition when fuel feed system is lower than required.

Does it mean that, in normal condition, APU fuel boost pump is OFF and fuel is supplied to APU by Main Engine Boost Pump (or Engine Driven Pump)?


texts: Why don't we use elevator trim as the primary flight control?

texts:
One thing you're repeatedly told as a student pilot is to fly with the stick (or yoke), not the trimmer. To select a new pitch attitude, fly to it with the stick, wait for the aircraft to settle, and then trim away constant forces.

But the position of the elevator trimmer is roughly the same for the same cruise configuration. It would be a lot easier to mark the trimmer with "level flight at 80", "gliding descent", and "best climb" positions, and just move it to those positions (before or after setting the throttle appropriately) directly. The trimmer would be the primary means of setting attitude, with the front-back axis of the stick or yoke for temporary adjustments (e.g to bring the nose up a little in a turn).

So why aren't controls designed to be used that way, and why do we fly with the stick?


texts: What is the "tennis ball between cylinders" trick used by flight instructors?

texts:
From this answer, "A tennis ball stuffed in between two cylinders -
a common flight instructor trick to see if students are doing a thorough preflight".

A place between the two cylinders is not the expected place for the tennis ball to be, but how does in general this "trick" work? I tried to Google but only pull out the mentioned answer.


texts: Are the terms "Coupled approach" and "Hand flown approach" strictly defined?

texts: I was looking on SE and also Google for the answer, but couldn't find anything. My question is when to log an approach as coupled or handflown? All of the approaches I fly are CAT I but the aircraft's autopilot has a coupled approach mode


texts: What is transmitting this radio signal @~110.515MHz and for what purpose?

texts:
I was scanning the local aviation radio frequencies, and came across an odd signal (listen to a recording here).
It's at around 110.515MHz, and it seems strong within a 30 mile radius of Shropshire, UK (haven't tried tuning in further afield).

Not sure if it's relevant, but there are a couple of RAF bases nearby (RAF Shawbury and RAF Cosford).

I presume it's a navigation aid, but couldn't find anything listed on that frequency.
I was hoping someone would recognise the sound and be able to tell me what equipment is transmitting it (e.g. NDB).


texts: Flying to Paro, Bhutan requires a special crew, what are the regulations?

texts: I would like to fly from Geneva to Paro, Bhutan on Gulfstream GIV-SP. I was informed that I have to take a specialized pilot from Delhi. Can anyone guide me what are the formalities and what are the solutions?


texts: What are the requirements to obtain an FAA private pilot's license in Bosnia?

texts:
I'm a US citizen currently living in Bosnia. Before I left the states, I was working on getting my PPL.

I currently have about 65 hours and was very close to finishing, but I was unable to do so before I left because of inclement weather and preparing for the move.

Would I be able to finish getting my license in Bosnia?

Are flight requirements the same? Would the flight hours transfer?

If I complete my license here would it be valid in the states?


texts: What is this strange thing under Tu-95 which looks like a horse-fly's eye?

texts: I was seeing this photo and saw an strange thing under the bomber. Too much looks like a compound eye. What could be it?


texts: What are some Anti-icing solutions for small planes without an on-board system?

texts:
When flying during the winter, is there anything I can do to increase my margin of safety, such as anti-icing fluid?

I've heard of people spraying their aircraft with propylene glycol, but am curious to know if this will do anything to prevent ice after takeoff, especially without a thickener.


texts: Are helicopters impacted by fog more than airplanes?

texts:
With the crash of Kobe Bryant's helicopter, it seems a lot of focus has been placed on the helicopter flying low in fog (under "special VFR"). However, I've seen several suggestions that the helicopter should not have been flying at all

Weather reports indicated that a low cloud cover was present on the day of the crash, further complicating flying. Bryant's pilot was operating the craft under a special clearance for poor weather conditions and reportedly had experience in such situations.

The pilot was IFR rated, but if the investigation proves pilot error it raises the question if helicopters should be more limited in fog. Wired makes it sound even more dire

Flying without sight of the ground or other landmarks can quickly become dangerous, Whitcomb says, because helicopters are not inherently stable. Just staying level and on course demands working four controls at once, using your hands and feet, and keeping track of how each input affects all the others. If you lose sight of where you are and you don’t use your instruments properly, you may not realize you’re turning, or dropping, or even upside down. “You’ll get disoriented within seconds,” Whitcomb says.
Navigating by instrument can also be mentally taxing, says Scott Shappell, who chairs the Department of Human Factors and Behavioral Neurobiology at Embry-Riddle Aeronautical University. He compares visual flight conditions to driving down a familiar highway. Flying by dashboard is more like driving through Rome for the first time—while working a stick shift. “It’s definitely more work,” Shappell says. “The risk goes up.”

Are helicopters really that much more impacted than airplanes by fog?


texts: Does FAR Part 121 require at least 45 minutes of fuel remaining upon landing?

texts: Assuming the reported weather does not require an alternate airport, if an aircraft being operated under FAR Part 121 domestic IFR lands at its planned destination airport and does not have at least 45 minutes of fuel remaining, is this a violation of the regulations?


texts:
What is the cost of the engine Boeing 747 Model 400?
Including what component of the cost of the aircraft engine Gies


texts: With the fuselage plugs forward of the wing, would this mean the engines are closer to CG, therefore no need for MCAS?


texts: How does scaling of UAV size impact range?

texts:
Lets say you have two autonomous small aircraft, one with a wingspan of 200 cm and one with 400 cm. Both have the same general design. They are both optimized for travel distance on one full tank (gas tank size, engine size, optimum speed, etc). Which one has greater range?

In other words, does it help to be large or small if you want to make a travel distance record?


texts: Where does the 90 seconds limit for plane evacuation come from?

texts: New airplanes have to confirm that all passengers have to be evacuated within 90 seconds or they wouldn't be certified by aviation authorities. But where does the 90 seconds limit come from? Why isn't it 60 or 120 seconds? Is it based on a series of studies or is it just a nice round number that was chosen based on a rule of thumb?


texts: What is the cause of the noise heard when the landing gear is deployed?

texts: Why is it that on most airliners, when the landing gear gets deployed, you always hear a loud noise like a bang. Is this due to the equipment locking in place or is there some other reason? As an external person I would think that there should be a mechanism that pushes it down slowly, avoiding this noise but it doesn't seem the case.


texts: What is meant by these criteria for a stabilized approach?

texts:
Based on regulation, there are several criteria for when an approach is stabilized. I want to ask:

Only small changes in heading/pitch.

How small?

The aircraft is in correct landing configuration.

What are those configurations?

The aircraft speed is not more than Vref+20 or less Vref.

Is this IAS or CAS or TAS?


texts: What does an "X flagged" VOR mean on an en-route IFR chart?

texts:
Source: skyvector.com

Maybe I'm looking at the wrong sections / using wrong keywords in the chart user's guide.


texts: What do airlines do with planes at the end of a multi-stop route?

texts:
The question's kind of broad and simple, so let me be a little more specific. Take Southwest Airlines flight WN3223. This is a multi-stop, trans-continental route that starts at LGA in the morning, flies to DAL, then PHX, LAX, OAK and finally SEA with expected arrival times usually around 10:00 PM. This route runs daily.

Now, according to Flight24, sometimes the same tail number is used for the flight on consecutive days, more often there's a rotation. So the question is, what does the airline normally do with the plane between 10:00 PM one day and 6:00 AM the next (when a plane, if not the plane, is expected to be back in the gate at LGA)? Does Southwest just deadhead it all the way back to LGA? Do freight companies subcontract with airlines like Southwest to move boxes overnight on otherwise deadhead flights? Does the plane stay in Sea-Tac and is used for another flight number (possibly the reverse route)? Does the crew deadhead to a maintenance hub? All of the above?

EDIT: This question might be similar to the mentioned duplicate but I think it's more specific. I'm asking, more or less, how an aircraft used to operate a route that takes it across the country during daylight hours is typically "reset" so that it can fly that route again.

The assumption, of course, is that the plane does fly that route again on some cyclic schedule, which may itself be wrong; a look at the tail numbers available for WN3223 shows that none of the aircraft used for that route in the past 4 days have flown it again in that same time period, despite the planes used for older flights having ample opportunity to make it back to LGA for another run. So, I think my answer, at least for Southwest's routing model, is "the plane spends the night at SEA, then is sent on a new route number the next day, which may have nothing in common with WN3223 nor get the plane back in a situation to run WN3223 again".

Airlines running non-stop long-hauls probably have a more static schedule; an A380 might fly from Dubai to DFW, then turn around and fly right back, and that one route may be the only thing the plane is scheduled to do for weeks at a time.


texts:
As you can see in this picture the APU of the A400M is on the side under the right wing, including the RAM-Air-Turbine.

Why is the A400M APU on the side of the fuselage instead of the back?
Why is the RAM-Air-Turbine not on the bottom of the fuselage?


texts: I asked this question which led to another question of mine, What it the long rod just past the top of the nose of the Bell 206B helicopter and what is it's purpose?


texts:
There are various services that use world-wide Boeing Winds for forecast wind data which can be used to calculate an approximate flight time between two locations.  They usually have best case, worst case, and average case for each location, altitude, and date in the future.

I have searched and searched Google to no avail.  Where can this wind data be found, and how can it be used in a commercial product?

For those of you who don't know what the Boeing winds are, I found this description of their software product on am informal message board (not related to Boeing):

  PC WindTemp

  INTRODUCTION
  The Boeing PC Windtemp program provides global average and statistical winds and temperatures aloft over a 30 year
  period. These data are used primarily for comparative transport
  airplane performance and economic studies. The data may also be used
  for transport airplane route planning on an annual, seasonal, or
  monthly basis.

  Note: Actual winds and temperatures at a specific location and time
  may differ appreciably from those computed by PC Windtemp. Therefore,
  data from PC Windtemp must not be used for flight planning, aircraft
  dispatch, airborne flight navigation, or any other type of actual
  flight operations.

  PROGRAM FEATURES
  A seasonal and monthly database with global coverage from 1000 millibars (364 feet pressure altitude) to 10
  millibars (101,885 feet pressure altitude). Annual data updates to the
  most recent 30 year period. Airport codes and coordinates may be
  imported from a text file in a comma separated value (CSV)
  format Calculates enroute wind and temperature for up to 50 airport
  pairs at a time. Calculates enroute wind and temperature for simple
  great circle tracks or tracks with up to 250 waypoints, with or
  without altitude changes. Calculates average enroute wind and
  temperature or any reliability (quantile) between 50% and 99%. Months
  or seasons, reliabilities, altitudes, and speeds may be nested for
  input efficiency. Formatted and text output reports are
  available. Program subroutines (DLLs) can be called from other
  programs written with C++ or Visual Basic in order to incorporate
  Windtemp functionality in those programs.


texts:
I'm wondering how many 747-200's are still in service?
I know for sure Rolls Royce is using one for testing purposes.
And the one from the US Forces.

Are there any civilian operated ones left?
Does somebody have photos?


texts:
Are there any airports with ILS working CATIIIC?

What do the charts for this procedure look like? Is there a missed approach procedure?


texts: Pilot passed out in a small GA plane. What can a passenger do?

texts:
There is another question about airliners and if someone not qualified could land them. My question is about the steps I should take to stay alive in a small GA plane.

Let say a friend of mine invites me aboard a small aircraft (like Cessna 172 or equivalent).
At some point my pilot friend passes out for some reason. What should I do considering the following:

I'm not a pilot.
I'm seated in the co-pilot seat.
I spent hundreds of hours on Flight Simulator (a few years ago).
I've been initiated to fly a small aircraft (1 session covering the very basics), but no take-off/landing exercises.
The weather is good.
Aircraft is in good condition.
The tank is full.
Area has ATC and I know how to operate the radio.

This is my guess:

Hold the plane's level and heading
Slap my friend to try to wake him up
Send "Mayday" asking for assistance and technical guidance
Try to follow ATC instructions as well as I can

Does this look good? What should be done differently?


texts: Why were the 747SP's trailing-edge flaps so much different than those of the -100/-200?

texts:
I read several decades ago about how the 747SP's trailing edge flaps were substantially redesigned from those of the "original" 747-100/-200s.  The images on the 747SP Wikipedia page clearly show what appears to be an unslotted Fowler flap - contrast with the triple-slotted Fowler flap of the 747-100.

Why the major re-design?

Related sub-question:  The Wikipedia page also mentions "... the SP's heavy wings" as one of the factors contributing to its cancellation.  But, the SP had the same wing (modulo the trailing edge flaps) as the -100/-200.  How could its wing be considered "heavy" in this context?  (I'm thinking maybe it has to do with moments of inertia and/or size relative to the fuselage, but hopefully someone else here can clarify this.)

Wikimedia Commons (from the Wikipedia 747SP page)


texts:
In the US, is there a highest legal altitude allowed for certain planes and does it depend on the plane? I heard from a sort-of-reliable source that the maximum is 45,000 feet but I haven't been able to confirm this. I ask since a plane I travelled in very recently was travelling at an altitude of over 55,000 feet and, when it did, turbulence was terrible (some told me I was lucky to be alive).

Note: I have tried Googling this and have found no answers.


texts: Are passengers really not allowed to change seats before take-off due to weight and balance?

texts: Just boarded an A320 with many open seats (Spirit), and the flight attendant said we may not change seats until at altitude due to weight and balance.  Is he just trying to prevent pax from moving around while the crew is busy moving around the cabin, or is this a legitimate issue?  I feel it must be the former, in which case I feel they're being a bit deceptive.


texts: Why does the Aurora D8 have vents on the bottom of its fuselage?

texts:
The Aurora D8 is a concept of an experimental aircraft (not an actual aircraft for now), described in this site. It's discussed in this question here on Aviation.SX.

I was watching the embedded video on the website I linked to, and it seems to show a couple of (intake?) vents on the bottom of the fuselage. You can even see this in the freeze-frame before playing the video.

What could these be used for? Do they suck in air for use in the engine? In the cabin? Elsewhere?


texts: Does the expression "stall speed" have a definition?

texts:
I read, not only on this site, that the stall speed of an airfoil doesn't exist, and I usually make the effort to stay away from this expression.

While an airfoil can stall at any airspeed, it's clear that the stall speed refers to the airspeed at which the stall occurs in an horizontal 1G flight.

Stall speeds for B747-200 (n=1). (Source).

This speed is the lowest one that can generate a vertical component of lift equal to the weight with the airfoil at its stall angle of attack.

I would compare this implicit assumption with the maximum airspeed of an aircraft: It's clear we are assuming at least an horizontal flight and a standard atmosphere, etc, else this speed can be anything too.

So what's wrong with this definition of the "stall speed"? Is the stall speed defined in the aerodynamics field?

Example of use: Stall Speed (Dr. Mustafa Cavcar).


texts: How prevalent is traditional radar tracking of commercial aircraft?

texts:
In many media reports regarding air incidents such as AirAsia Flight QZ8501: What We Know About the Missing Plane from NBC News I often see a phrase such as the following:

  By the time it had been given clearance, just four minutes after its last correspondence, the jet had disappeared from radar, Tjahjono told the news agency.

From various maps I've seen it appears the aircraft went missing over 100 km from any major land masses / airports and it made me wonder how far commercial aircraft would normally be tracked by traditional radar that sends a ping and waits for an echo from a typical airport?

I'm guessing in many cases media tend to use the term radar interchangeably with transponder technologies such as ACARS but I'd still be interested to know the limits of typical radar installations and how prevalent it remains in modern commercial aviation.


texts: Why doesn't the A330/A340 have a stickshaker?

texts:
When an A330/40 is in alternate law1 and approaching a stall, it has a stall warning composed entirely of a cricket chirp and a voice saying "stall, stall".  Most other aircraft, in contrast, have a stickshaker, which vibrates the stick when the aircraft approaches a stall.

Pilots are, as demonstrated by numerous crashes, very (very very) good at tuning out aural warnings, whereas a stickshaker provides a powerful tactile cue that is very difficult to ignore; so why doesn't the A330/40 have a stickshaker?

1: In normal law, the A330/40 has no stall warning, as its automatic angle-of-attack protections supposedly make it impossible to stall the aircraft by pulling on the stick.


texts: How can we recover from a tailplane stall?

texts:
I was studying for icing and a tailplane stall. I have looked up some internet pages and instrument flying handbook, and found the procedure below.

raise flaps to the previous setting. (To reduce down wash from the main wing so that reducing negative angle of attack of the tail and break the stall)
apply nose up elevator pressure (I don't get it. The nose up pressure will make the elevator to go up and wouldn't this increase the negative angle of attack and worsen the stall?)
do not increase airspeed unless it is necessary to avoid a wing stall. (Why shouldn't we increase airspeed?)

So now I'm trying to understand the reason why should a pilot do such actions. Can you help me out?


texts: Where to find fuel type & fuel consumption info for PW 1000G engines family?

texts: Where I can find the information about fuel type and fuel consumption for PW 1000G engines family?


texts: What lead time is required to change an already submitted flight plan?

texts:
A government agency of an EU country commissions a private company with a chartered flight from Europe to Africa/Asia/... (e.g. to involuntarily take people to a specific country).

Then it wants to change the time of departure with short notice. How long before the changed departure time do they need to file the new flight plan and what are some obstacles for changing it at the last minute?


texts: Is a massive parachute coming out from an ejectable fuselage technically possible for a commercial aircraft?

texts:
And would it save lives?

This video quotes no sources (except the usual "someone") but has gone viral:

https://www.facebook.com/ScienceNaturePage/videos/761924050606522/


texts:
I understand the basic concept of the pitot tube in that it measures the air pressure coming into the tube in order to compare it to a static pressure measured elsewhere on the aircraft.

The B-2 bomber, however, has pitot plates in order to eliminate the radar reflectivity of the pitot tube.

How do these plates work, as compared to tubes, and why aren't they more common, since a flat surface that is less radar reflective would also, likely, be more aerodynamic?


texts: I spotted these three planes flying east then turning south.  They were over the Hopi reservation and heading toward Winslow, AZ at 10:42 AM local time (MST), today February 5 2021.  They were at 15k to 20k feet or so.  Can anyone explain?


texts: Can I find out why an aircraft squawked an emergency code (7x00)?

texts:
I have recently been using a mobile app to track flights, which is really cool.  I live in the rural heartland of America, so it's an event for me to see an A380 actually flying.

Every once in a while, a squawk 7700 alert will come up, which I understand is the emergency transponder code. There are more, such as 7600 and 7500, which I find are less common.

My question is, is there a way to do some post-mortem followup as to why the aircraft squawked the code?  Is this public information that can be found by some agency such as the NTSB?


texts:
Does the C series from Bombardier incorporate composite materials into the fuselage and/or wings? If so, what material is used, and where is it applied. Because of Airbus's 50% market share in the project there might be different technologies applied.
Any help is greatly appreciated.


texts: What is the asymmetric feature on the rear of a Sukhoi Su-47?

texts:
I saw this part on the rear of the Sukhoi Su-47 Berkut, and I can see that it is asymmetric. Is it maybe for interference, or is it a take-off aid because the Su-47 is a STOL plane?

What is it and why is it asymmetric?

Edit:Second picture is mirrored


texts: Controllability vs. Stability in PHAK. Is it an error?

texts:
My understanding on the relationship between stability and controllability has been that greater stability means less controllability and vice versa. This post confirms that. However, I've came across this paragraph from PHAK 5-43 today:

  Generally, an aircraft becomes less controllable, especially at slow
  flight speeds, as the CG is moved further aft (my emphasis). An aircraft that
  cleanly recovers from a prolonged spin with the CG at one position may
  fail completely to respond to normal recovery attempts when the CG is
  moved aft by one or two inches.

Aft CG means less stability, so if I'm not mistaken, the phrase is basically saying less stability leads to less controllability. How should I understand this statement? Should I understand that, although controllability and stability are generally opposed to each other, when it comes to a stall or spin recovery, the opposite is true? Or is it simply an error?


texts: My driver's license was suspended for not having insurance. Should I even bother to apply for a medical?

texts:
My insurance lapsed for a few days, and during that few days that I got caught.

Furthermore, it's the second suspension in my life because I got a bunch of tickets when I was younger.

I hold a sport-pilot license which would be invalidated if I was rejected for the medical.


texts: Is navigation around thunderheads done at the pilot's discretion?

texts:
It's my understanding that if a pilot is flying over an ocean or otherwise uncontrolled airspace and they encounter a cumulonimbus, they navigate around it at their discretion.

How does this happen in controlled airspace though? What instructions do ATC and a PIC typically exchange if a PIC wants to request navigation around a thunderhead?


texts: Why does condensation form on the wing especially during take-off and landing?

texts:
To start off, yes this question was asked before, yet I don't find the answers satisfying and here is why:

It appears to me that this phenomenon only appears during the approach phase of a flight and during low speed turns, or rather when the angle of attack is rather high. Also, usually the flaps are deployed when it happens, yet I'm not sure if that makes a difference.

Considering this, the answers wouldn't necessarily answer my question. They all talk about how there is a lower pressure above the wing, which causes the dewpoint to drop and thus makes the water condense. But is there a "lower" lower pressure when the angle of attack is higher and therefore making this phenomenon occur more often? Or is the point at which the laminar airflow gets turbulent (which moves forward as the aoa is increased) an important factor here?

Here is a picture to show what condensation I mean:

And a more extreme one:


texts: How does humidity's effects on density altitude get factored into Takeoff Distance Performance Charts?

texts: Given that density altitude is a function of Pressure, Temperature, and Humidity, and most takeoff performance charts adjust takeoff distance as a function of pressure altitude and temperature, how is the humidity effect on density altitude taken into account?


texts: Do strike aircraft turn off their datalink?

texts: As far as I know, it is normal procedure for aircraft on a strike mission to go into radio silence at a certain point of the mission, as to not give of any unnecessary emissions that could warn the enemy of the aircraft's presence. I was wondering if this also applies to the datalink system or whether there is some kind of mode for the datalink in which the aircraft only receives datalink information, but doesn't transmit.


texts: How are AFTN costs charged to ANSP's and Airspace Users?

texts: I'd like to know how ANSP's like the FAA/SENEAM/etc.. get charged for sending and receiving messages over AFTN. I'm wondering if it is on a per characher/message basis or if they pay in bulk. Also, how do private Airspace Users or 3rd parties like Jeppesen pay. Since this network is actual copper and is so old, I'm wondering if SITA makes pure profit or if it is more complex than I understand.


texts: Is emergency floor lighting fluorescent?

texts:
I just read this question (about emergency lighting) for which nobody highlight the title mention fluorecence. As this lighting's requirements include operability with failure of normal electrical power, having fluorescent strip doubling a ramp of lights make sense. However, the pictures illustrating the answers shows seat-mounted lights.

My question focus on the emergency floor lighting installed on the floor. Do this kind of emergency lighting use fluorecent elements?


texts:
I realize this is slightly off topic, but there's no other SE site that it would at all fit into.

Anyway, I was just thinking about Neil Armstrong, and I wondered how many confirmed, and/or possible, kills he had in combat.

I tried to look it up, but couldn't find anything with Google.


texts: How to calculate W/V from true HDG/TRK/GS using a CRP-5 flight computer?

texts:
I am currently studying for my EASA ATPL (airline transport pilot license) and one of my subjects is General Navigation.

I have stumbled across this question (picture) that has completely stumped me, I have not been able to find help anywhere else. I know it can be solved by drawing wind triangles but I am solely interested in solving it using the CRP-5 flight computer.

I am very much used to calculating desired headings for a certain track when given wind, but not the other way around. Any help would be greatly appreciated.


texts: Could a pilot navigate using distances and radials from an RNAV waypoint, similar to VOR navigation?

texts:
I know that typically RNAV navigation involves a list of waypoints, and the aircraft simply flies from one point to the next.  What I'm curious about is if a procedure could be developed (as a special engine out procedure, for example) that would be something like

  Depart on runway heading. At distance 2nm from FOBAR waypoint, turn
  direct to FOBAR. Track radial 090 outbound from FOBAR.

Would the instruments in an RNAV equipped aircraft allow a procedure like that to be flown?  Would it require a certain system (say only from a certain manufacturer), or require additional systems (like an FMS)?

CLARIFICATION FROM COMMENTS:
I understand that a procedure like the one above would not be typical or preferred, but in very hazardous terrain (for example) with no real other options, would the pilot simply have the tools available to be able to fly it?

If it matters, I'm particularly interested in commercial aviation and answers that would be applicable to any airport worldwide.


texts: What is the difference between "Type Certificate" and "Certificate of Airworthiness" for an aircraft?

texts: I want to know what exactly is "Type Certificate" and "Certificate of Airworthiness" means for an aircraft.


texts: Why does the European MALE RPAS UAV use twin engines?

texts:
I don't know why the European MALE RPS UAV designers chose to use twin engines?

I know two engines are expensive but add safety...

Does choice is to obtain mass flow @ Medium altitude(low air density)?
especially with relatively low speed(maybe 0.4~0.6 Mach)...

I guess that as density drops off at higher altitudes, the machine ingests less air mass, resulting in reduced power and reduced thrust...

To need larger flow areas (larger diameter)?

Unlike RQ UAV series...


texts: Inspired by the first comment here, and considering they are called "boats", do flying boats carry anchors?


texts: What counts towards the 250 hours required for CPL?

texts:
FAR 61.129 states that "for a commercial pilot certificate with an airplane category and single-engine class rating must log at least 250 hours of flight time as a pilot that consists of at least:

  (1) 100 hours in powered aircraft, of which 50 hours must be in airplanes.

  (2) 100 hours of pilot-in-command flight time, which includes at least—

      (i) 50 hours in airplanes; and

      (ii) 50 hours in cross-country flight of which at least 10 hours must be in airplanes.

  (3) 20 hours of training on the areas of operation listed in §61.127(b)(1) of this part that includes at least—

      ..."

What counts towards the 250 hours of flight time as a pilot?  Planes? Helicopters? Gliders? Hangliders? Paragliders? Paramotors? Wingsuits? Hot air balloons? Lawn chairs with helium balloons attached to them?

I would think that the skills from flying balloons is not very transferable to planes, so what are people's views on half your hours being from "flying" a balloon, or something similar?  E.g. What do pilot examiners, employers, insurance agents, think?


texts: Can FMC be programmed to do fast maneuvering in fighter jets?

texts:
As we know we set the flight path etc in FMC but can it be pre programmed to do high speed maneuvering and shoot the ammo as per the preset conditions?

It could be kind of self moving UAV with the pre stated path, waypoints, targets to hit and the return path along with the type of ammo to hit depending upon the kind of target.


texts: What are the differences between "ground stop", "ground delay", and "gate hold"?

texts: I've heard several terms referring to air traffic control procedures that restrict movement for a certain period of time: ground stop, ground delay, and gate hold (plus others I'm sure I'm forgetting at the moment). How exactly does each of these procedures work? And do they affect arrivals, departures, or both?


texts: How are the services kept running on a plane without an APU?

texts: I have seen several aircraft that do not have an operative APU, so how are lights, air, and other systems kept running?


texts: What prevents the use of a multi-segment ILS for non-straight approaches?

texts:
An ILS, consisting of a localiser beam to provide lateral guidance (which can also be used on its own for a non-precision approach) and a glideslope beam to provide vertical guidance, is (currently) indispensable for precision approaches in IMC, but comes with a few disadvantages.

Chief among those is the fact that an ILS only supports approaches that are ramrod-straight all the way in from the outer marker, when such an approach path is often impossible or undesirable...

...sometimes because something too solid to fly through is in the way (for instance, the infamous approach to runway 13 at Kai Tak, which, due to an inconveniently-placed mountain, necessitated coming in at a large angle to the runway and then making a sharp right turn at very low altitude at almost literally the last moment; an instrument guidance system - basically an ILS without the “landing” part - was added in the 1970s to provide precision guidance for the part of the approach before the turn, but the turn itself and the final approach segment still had to be hand-flown visually, an exceptionally difficult task even in good weather)...
...and sometimes because someone else is using part of the airspace in question (for instance, the four major airports in the New York area [JFK, la Guardia, Newark, and Teterboro] have numerous intersecting approach paths, which, as the approaches can’t be bent or segmented to keep out of each others’ way, frequently forces la Guardia and Teterboro to land aircraft on runways with strong crosswinds [because the ILS approach paths for their more optimal runways would risk causing MACs with aircraft on ILS approaches into JFK and/or Newark]; on the other side of the continent, the approach paths coming into LAX from the east pass near or over Ontario, which has caused quite a number of near misses in the vicinity of the latter airport).

It doesn’t seem, conceptually, like it should be too hard to break up an ILS approach into two or more segments, each with its own localiser and glideslope, and with the beams from the pre- and post-bend segments intersecting at the bend in the approach path.  As most aircraft are unable to turn on a dime, they would need to start turning a bit before the bend in the approach, but this could be easily handled by having another instrumental aid (for instance, a third localiser) indicate when to start turning; if the bend in the approach were sharp enough for the aircraft to have trouble locking onto the post-bend beams, another localiser and glideslope, with their beams tangent to the midpoint of the turn, could be used to assist the aircraft round the bend.

All of this would also work for segmented localiser approaches, with the added advantage of being easier to implement (no need for the multiple glideslope antennae, just the localiser ones).

Here be an illustration of what I’ve got in mind:

Why aren’t segmented ILS and localiser approaches used in practice?


texts: What is the shortest regularly scheduled commercial flight?

texts:
Interesting to know is this flight profitable or not.
Why this route exist?
Maybe train or car will be cheaper?


texts:
EASA can issue an ETSOA (Euro-Technical Standard Order Authorization/Approval) for certain equipment design, to simplify installation authorization on an aircraft type design.

I found no notice of such an ETSOA expiring at a certain date or for a certain certification basis. Still, at some point regulations evolve and ETSOA'd equipment may stop meeting those regulations. How is this managed?

As an example: suppose a few years ago, an equipment was designed  and manufactured as per some ETSO, and approved by EASA for that ETSO under a certification basis including the now obsolete DO-178B.

Now or in the near future, an aircraft manufacturer wants to use that equipment on a new aircraft type that is required to use the updated DO-178C. What would the aircraft and the equipment manufacturers have to deal with as extra certification work for that equipment? And in the case there is no extra work, how will the EASA deal with new regulations in the years to come?

(this question is not specifically targeted at EASA's ETSOAs: consider the same question for FAA's TSOAs and similar mechanisms in other countries)


texts: What is the difference between conventional VOR and Doppler VOR?

texts:
There are two types of VOR (VHF Omnidirectional Range) navigation beacons; the conventional VOR (CVOR) and the Doppler VOR (DVOR).

What are the differences between them? Specifically I would like to know:

Do they generate the same navigation signal?
Can they be used by the same receiver, or do VOR receivers need to be specially adapted to DVORs?
Is one more accurate than the other?
Is one more susceptible to interference than the other?


texts: What are the effects of headwind on ground speed and take off run?

texts:
I'm just making sure I got this right.

For the take-off roll, having headwind is preferable, so there is a positive airspeed.

For the en-route segment, a headwind is not ideal and increases time to destination, whereas a tailwind is more favorable.


texts: Is there a boomless sonic technology in any state at this time?

texts:
I've heard rumors about airplanes being on the horizon with "boomless sonic" technology, or the ability to fly supersonic without creating that hazardous shockwave.

This would be very valuable for business travelers who want to cover populated areas at high speed. These aircraft would presumably be certified to fly at supersonic speeds where it is now forbidden due to the damage of sonic booms.

Does this technology exist? Is anyone on the trail to making this work? Is it even possible?


texts: why some airplanes have their exhaust gases vectored above the wing?

texts:
I was looking at images of the SkyCourier shown below

and i have noticed the asymmetrical exhaust pipes in both engines (one pointing up and one is straight), doing my research on the internet, i found that it is used to take advantage of the Coanda effect and the flaps so that the gas moves from the top side of the wing and then gets deflected downward for a high lift effect in takeoff...

Yet i believe you can get the same effect if the gases were vectored under the wing and made hit the flaps, so why would they vector the gases above the wing, and why the second exhaust is not deflected upward ?


texts: Why an external RAT on this early propeller plane at Charlotte?

texts:
At the Charlotte airport, I caught a glimpse of the Bellanca 14-9L with State Airlines livery they have on display. They call the Bellanca the first plane with retractable landing gear but that's not what struck my attention:

There is a ram air turbine generator visible  and permanently located between the landing gear (circled). I only know of RATs as providing emergency power for airliners -- and they are only deployed (pushed outside) when they are needed. The other use for them is apparently on cropdusters.

Why did this airplane need a RAT permanently installed? Wouldn't it be much more power efficient and aerodynamic to provide DC/AC power through a magneto or alternator on the engine?

Late note: I looked at pictures of other Bellanca 14-9L and they don't show a RAT. Perhaps this means that this plane was not a passenger craft (as its "State Airlines" livery indicates) but was in real life a cropduster?

(Photo by author. Released cc by-sa)


texts: What are the performance trade-offs in the Icon A5 spin resistant airframe?

texts: I've been looking at the website for the Icon A5 amphibian LSA and noticed the wing section clearly has two different cross sections, presumably to facilitate the stall and spin resistance of the aircraft.  One of the videos on the site shows the wing as it stalls and the tell-tales attached to the wing clearly show the flow separation for the inboard section of the wing while the outer section still indicates attached flow.  I would guess that this wing must have either some performance trade offs or else it's a significant cost, otherwise why wouldn't most GA aircraft have this feature?  Perhaps fabrication in sheet metal would be difficult as I believe this aircraft is mostly composite construction.


texts: Why are holding patterns in an oval shape? Why not circular or more square-like?


texts: Is a braking rotation immediately after touching down a known maneuver?

texts: In this video the airliner landing on grass rotates high up after touching down, looks like more than it would do during take off. Is it a known possible way to drop the speed or it was more for the show? Is this maneuver ever used during more conventional landings?


texts: Why are contrails not visible from the cabin?

texts:
If you observe a plane flying whilst on the ground, plenty of times you will see contrails:

Why are they not visible from the plane itself when sitting in the most rear part of the cabin even by trying to look towards the rear of the plane fuselage? They seem to be quite close to the engines.

Knowing that they form due to the heat, they should be seen quite close to the engine.


texts: The autopilot of an airplane is frequently referred to as "George" (for example, in this answer). When did this nickname enter common usage, and what is its origin? Please cite sources if possible!


texts: I have some combination of joysticks and a rudder that I'm trying to use for helicopter flight simulation on my PC. Where is the radio PTT button on a Robinson R22 helicopter?


texts:
Operator on phone, GoAir plane hits aerobridge

How is such a 'puncture' repaired? Is the cabin pressurization also affected by such a puncture, and approximately what is the cost incurred to repair such a puncture?


texts: Does anyone know of sources for ATA 206?

texts:
I have been seeing references to 206 ATA recently. However, it appears to be so new that very little Google indexed information is available.

Has anyone dealt with this particular  ATA chapter, and if so are there any publicly available resources?

Please note: I am not talking about USS Pinola (ATA-206).


texts: I am about to start my PPL soon (still flying in FSX) and I do not understand one thing. As per FAR 91.159 if my altitude is above 3000' AGL I must maintain certain altitude depending on my course, BUT what would be my reference point to know that I am above 3000' AGL? Departing airport? MEF from chart? or just look out my window? Thanks!


texts: What was wrong with my answers to how to deal with low volt annunciator, and icing, both in IMC/IFR?

texts:
I have questions for emergency situation in IMC.

I was asked about low volt or icing condition IMC from my school's checker.

The checker said "if you see low volt annunciator on PFD how can you deal with this problem under IFR flight?" So I answered "first contact ATC, and request radar vector to nearest airport and then, I will follow the check list for low volt annunciator." However, the checker said this answer was wrong.

Also, I got a similar question from the checker which is icing condition during IFR flight.  "When you face on icing condition under IFR flight, how can you deal with this situation?" So I also answered "first, I will turn on pitot heat, deforster and cabin heat, After that, I will do climb or descent to get warm air to rid of icing and try to get VMC condition. However, I will consider the altitude which is be higher than MEA. Also, I will do follow the check list for icing. If the problem is not solved, I will let ATC my problem, and request radar vector to nearest airport." But, the checker thought this answer was wrong too.

Is there any problem from my answers? Or could you let me know how I can deal with this low volt or icing situation in IMC?

Thank you very much!


texts: Is pitch-flap coupling an aerodynamic effect or an intrinsic property of a delta 3 offset?

texts: I am modelling a propeller, in particularly the equations of motion of the various pitch/lag/flap angles as the propeller is turning around. The blade includes a $\delta_3$ angle, which provides pitch-flap coupling by offseting the flap hinge slightly (see image below). From what I understand, his  pitch-flap coupling essentialy reduces the flap amplitude by varying the pitch. However, is this an aerodynamic effect? Or an intrinsic effect that is a result of the kinematics.


texts: What are the different vehicle roadways markings?

texts:
I was going through the AIM (Aeronautical Information Manual) chapter 2, which talks about airport lights and markings. There are 2 types of lines that designate a vehicle roadway. One is a solid line and the other is a zipper line but I could not understand the difference between the two.

  Vehicle Roadway Markings. The vehicle roadway markings are used when necessary to define a pathway for vehicle operations on or crossing areas that are also intended for aircraft. These markings consist of a white solid line to delineate each edge of the roadway and a dashed line to separate lanes within the edges of the roadway. In lieu of the solid lines, zipper markings may be used to delineate the edges of the vehicle roadway.


texts: Why do jet engines take a long time to throttle down?

texts:
Apparently jet engines can take several seconds, up to ten or fifteen seconds, to go from full power to idle.

Why is this? Can't a simple fuel valve shut off fuel flow? Or reduce it to whatever flow rate corresponds to idle? Either of these, if done with a valve, should happen almost instantly as far as I can tell.

This would surely cut thrust, regardless if the engine still spins for a while. Is there something dangerous about this idea? To me it seems like a fuel valve can close and open again as many times as it wants.

Note: I'm interested in turbojets and turbofans. And I care about throttling down only.


texts: Why are rules regarding the use of oxygen masks by commercial pilots often ignored?

texts:
I was reading an article recently on the effects of rapid depressurization when I came across this tidbit:  According to FAR 135.89.2, aircrews of part charter craft flying pressurized aircraft above 35,000 MSL are required to have one member of the aircrew on oxygen at all times.

I've seen a few videos of charter pilots flying planes around FL410 and I don't recall any where they had masks on (admittedly, there are not a lot of small business jet charter flight videos out there.) In general, though, it seems the rule is ignored.

So, why isn't the rule followed?  Why don't pilots seems to wear oxygen masks in situations the regulations say they are supposed to?

Addendum:

In the original, unedited, version I made the mistake of thinking FAR 135 applied to airliners, when that's clearly 121 that applies to airliners...

Still, in FAR 121.333 it states that the rules around airmasks for commercial airline aircraft (over 30 passengers) require that pilots always have oxygen when they are either a) over FL410 or b) over FL250 and one of the flight crew leaves the flight deck.

Of these conditions, it seems condition A is followed by default (flying under FL410), but condition B is often ignored.  So I'd be curious why that part of the rule isn't followed as well.

Basically, I'm asking why pilots generally don't wear oxygen masks when regulations require that they are supposed to.

A big thanks to Zach Lipton for pointing out my error to me.


texts: Identification of this control panel for a four-engine plane

texts: While cataloguing a printer's copper plates I came across a control panel image, and I have attached it here in the hope someone can identify what plane it's from. The Lorenz blind-landing instrument gives an indication of the period.


texts: How do I calculate the total cruise power from the propellers accounting for the losses?

texts:
Let's say I have an aircraft with four propellers (see diagram below) and I am supposed to calculate the cruise power required to drive the aircraft forward. The  wing creates the lift and propellers provide the forward thrust.

If I don't account for the wake of the front propellers affecting the rear propellers it's easy. I just have to calculate the thrust required and get the power. But how do I account for the losses and the actual power required?


texts:
I have a basic question that I cannot seem to find a solid answer for:

How does a gust affect a swept wing?


texts: Why does not the lift produced by main wings create pitch moment?

texts:
Pitch moment is created by lift created by the horizontal stabilizers via the elevators.

But then main wings also create lift, why does not this lift enough to create pitch moment?


texts: What are the names of the vehicles to provide assistance to aircraft during the turnaround?

texts: During the turnaround many vehicles support the aircraft on the gate. What are the name of those "vehicles"and their purpose?


texts:
Avionics Full-Duplex Switched Ethernet (AFDX) is an avionics network patented by Airbus, developed starting with A380 and new standard in all new generation aircraft from Airbus factories.

I know that AFDX is Ethernet technology. But is it used the same Ethernet cable used to connect the computer to a LAN or to the Internet? Or is it used an improved version? Which are the differences between the two cables?


texts: What does the letter G mean in a runway identifier?

texts: Boulder Municipal Airport (KBDU) has runways 8 / 26 and also runways 8G / 26G. What is the significance of the letter G following the runway numbers?


texts: Are approach and departure procedures based on visual reference points official VFR procedures?

texts:
Pilots flying VFR follow clearances like the "mall visual" or "east channel departure." These are based on features of the local area that are easy to identify.

Are procedures like this official? Where could a reference be found for these procedures?


texts: Why does an airplane captain sit in the left seat?

texts:
For almost every airline, the captain sits in the left seat, and the first officer on the right.

We know that in most countries right-side traffic and some have left-side.
During training, the student sits in the left seat, and the trainer on the right.

Keeping these two points in mind, why does the captain always sits on left? It is not based on culture (see #1 above), and not on who has more experience1 to fly an airplane from both seats.

1: I know that there can be a situation when the first officer is more experienced than the captain, but most of the time, it is not the case.


texts:
On WikiPedia, the Progress D-27 is described as a propfan engine and the airplane it powers, the Antonov An-70, is described as propfan-powered.

This Air&Space magazine article contradicts that; it states that the An-70 is turboprop (not propfan) powered, as is the Airbus A400M.

And indeed the basic configuration of the D-27 and the A400M's
EuroProp TP400 turboprop are very similar:

4.5 m propeller diameter vs 5.2 m
14,000 hp vs 11,000 hp
two-shaft gas generator, third shaft to drive propeller
propeller driven through reduction gearbox
propeller blades mounted before engine
780 km/h max speed vs 780 km/h cruise speed
variabele pitch blades

The only significant difference is that the D-27 has two contra-rotating blade sets while the TP400 uses only one blade set.

Having contra-rotating propellers does not necessarily make a turboprop a propfan though (e.g. the Tu-95 is a turboprop aircraft).

So all things considered, what would make the  D-27 really a propfan but not the TP400?  Is there really a distinction between a propfan and a turboprop?


texts: Which 737 generations doesn't have Alpha Vane (Angle of Attack sensor)?

texts: I was wondering if all generations have this angle of attack sensor, especially after recent 737 MAX Lion Air accident.


texts: Reason for the multiple sidelobes in an ILS glideslope signal

texts: Why are there multiple side lobes in the glide slope signal from an ILS?


texts: How does the load factor vary when the aircraft pitches up/down?

texts: I know that when an aircraft starts rolling, it's load factor increases. But can anybody explain how does load factor vary when the aircraft pitches up/down? Does it increase/decrease?


texts: Which MEL categories would ground a commercial airliner if they're inoperative?

texts: Which Minimum Equipment List (MEL) categories would require a commercial airliner to be grounded (Aircraft On Ground or AOG) if they're inoperative? For example, any category A MEL item is considered an AOG item; is it the same for category B items?


texts: Are the first solo flights by a student pilot more dangerous?

texts:
The first solo flight is a nail-biting moment, not only for the student pilot, but also for the flight instructor who's sending him off.  In theory not having a CFI reduces the margin of safety compared to flights with an instructor (at the same point in a student's training).  I've also heard stories about mistakes and even crashes on first solo flights, and according to "Crashes of instructional flights" by Baker, Lamb, Li, and Dodd, solo flights account for about half of instructional flight crashes.

Yet even though the biggest safety measure- a CFI- is gone, are these student solo flights really more dangerous?  Are there any studies on accident rate among low time GA pilots vs (solo) students?  Also, are incidents more common in the first solo flights than at other parts of a student's pilot training?


texts: How do Airbus and Boeing aircraft handle Dutch roll?

texts:
I have some homework about Dutch roll filters. Dutch roll is something that is corrected by yaw damper systems, but I would like to know the different ways Boeing and Airbus deal with the issue of Dutch roll.

Is there a separate yaw damper system or is it part of the wider auto pilot system?


texts: Why does setting the Legacy 600's transponder to standby mode also deactivate its TCAS?

texts:
In 2006, a 737 operating as Gol Transportes Aéreos Flight 1907 crashed following a collision with a Legacy 600 business jet; the Legacy's transponder proved to have been in standby mode1 at the time of the collision (due either to a transponder malfunction or to the crew having inadvertently switched it into standby mode), which, obviously, prevented the 737's TCAS from seeing the Legacy and sounding an alarm.

However, setting the Legacy's transponder to standby mode also, apparently, deactivated its own TCAS:

  Considering, according to declarations, that the N600XL pilots did not perceive that the transponder had stopped transmitting and that, as a result, the TCAS was inoperative...  [CENIPA report, page 83.]

This is also, apparently, the result should the transponder fail outright:

  In case there is a Transponder failure, the operation mode and code selected are replaced by dashes in the RMU. An orange message “TCAS FAIL” will appear on both Primary Flight Displays (PFD) precisely in front of the visual field of view of both pilots, as shown by the pictures bellow [sic].  [CENIPA report, page 92.]

I'm not seeing the rationale for this; even if the aircraft's transponder fails or is switched off, there doesn't seem to be any inherent reason why this should require also deactivating the TCAS.  Even if the transponder can't, or won't, transmit, the TCAS should still be able to pick up signals from other aircraft's transponders, allowing it to continue to function, albeit in a receive-only mode.

So why does the Legacy 600's TCAS cease to function if the transponder is standing by or inoperative?

1: In standby mode, the transponder does not respond to any interrogation signals, either from the ground or from other aircraft.


texts: Why did the L1011's direct lift control help make good landings?

texts:
In landing configuration the 1011 had what was called “Direct Lift Control” or DLC. That feature was actually pretty cool. Once the airplane was in landing configuration the spoilers would come up to a neutral position of 7 degrees. If you moved the yoke forward, asking for an increased rate of descent, the spoilers would come up to a maximum of 14 deg but the pitch would not change. If you pulled the yoke back the spoilers would move toward 0 deg or stowed, thereby increasing lift and slowing descent. The DLC worked really well and made for super stable approaches with rock solid pitch attitude and rewarded you with “greaser” landings more often than other big jets I have flown.

Source
Why does altering sink rate without changing pitch make for a super stable approach and "greaser" landing? The explanation I can think of is that moving spoilers is faster than pitching, allowing faster reaction times to errors.
EDIT: B787 has something similar


texts: Are the flaps of a Cessna 414A fully extended at 15 degrees or at 45 degrees?

texts: When are the flaps of a Cessna Chancellor fully extended? At 45 or 15 degrees? Also, what are the range marks of its tachometer with Continental TSIO-520-NB engines?


texts: Volume differences between intercom and outside communications

texts:
While flying I can hear my instructor in my headset talking no problem, but when they (and me) are speaking with ground/tower the volume in my headset is much lower. Is there anyway to increase the volume of the communications outside of the airplane?
Sorry, but different airplanes I fly in (172's) have different radios so I can't definitively quote the radio models and since it is happening in different airplanes its not tied to one specific plane or radio.
Based on the post
Do pilots have separate volume knobs on the radio panel? I think yesterday we had a Garmin GNS430, the others look similar also.


texts: How exactly do ICAO's VOR-based minimum separation standards work?

texts:
This question is aimed at Air Traffic Controllers who are familiar with ICAO Separation minima.  DOC 4444 states the following:

  Lateral separation between two aircraft exists when: VOR: both
  aircraft are established on radials diverging by at least 15
  degrees and at least one aircraft is at a distance of 28 km (15 NM) or
  more from the facility (see Figure 5-4)

Note that i have highlighted the word "diverging". The only example given here is when two aircraft are flying away from the VOR (diverging).

Q#1. In this scenario the VOR is located at the airport. Two aircraft are departing that airport, when the leading aircraft is 15nm or more from the VOR on radial 020, the following aircraft is laterally separated when he flies on radial 035. Is this correct?

Q#2 What if both aircraft are less than 15 nm? How many degrees of separation must there be in that case?

Q#3 What about when one aircraft is flying away from the VOR and the other one is flying towards the VOR? AC1 is flying away from the VOR on R015 and is 20nm from it at FL060 . AC2 is flying towards the VOR on R030 and is at 25NM descending through FL060. Are these two aircraft separated?

Q#4 Same scenario as mentioned above, but AC1 is 10NM from the VOR and AC2 is 20NM from the VOR (same radials and levels as mentioned above).  Are they separated?

Q#5 What if both aircraft are flying towards the VOR? AC1 is flying to the VOR on radial 010 maintaining FL200, 30NM from the VOR. AC2 is flying to the VOR and is at FL210 35NM from it on radial 025. Does this mean that since you have at least 15 degrees on the radials, that AC2 could continue its descent through FL200?

Also are there any sites,videos, other manuals or resources that have a better explanation on ICAO separation minima (other than DOC 4444)?


texts: Is there any reason spoilers would deploy just after liftoff?

texts:
I was watching this video of a 747-8F taking off.

http://www.dailymotion.com/video/x273atd

Just after liftoff the air brakes and ground spoilers deploy on the left wing causing a sharp roll to the left. You then see the left retract and the right deploy rolling right. Then on the left again to correct.

The second and 3rd deployments on the video are obviously commanded by the pilot to correct for the roll.

Watching several other videos of the 747-8 taking off I don't see any others with spoilers out at any time during takeoff. On 747-8 are the spoilers connected to the ailerons to help with roll? If so, does it take a strong wheel movement to cause this? Why would they have deployed so quickly after takeoff, was this a control input by the pilot? Why would he make such an input?

It looks like they narrowly escaped disaster on this takeoff.


texts: What methodology did ICAO use to create the overall code nomenclature for airports?

texts:
If an airport is from North America, then it starts with K and so on.

How did ICAO get the letters from?
Why does the Philippines region starts with A?
Why do airports in Izmir have
LTBx prefix?
Did they do some random letter ballot box?
Also why they decided to make 27 regions?
Why Does The Arctic have so many codes and why multi letter codes?
Honoring the countries that operates the adjacent runways to the science facilities perhaps?

I wanted to ask multiple questions but how they got names questions are about the exact same stuff and probably has the same answer and Arctic is almost exactly about the same topic too but I don't think it really needs a seperate question.