texts: Why do wings prefer laminar flow if cd is lower for turbulent flows?

texts:
Can anyone please explain to me why we prefer to maintain laminar flow over wings, despite the fact that the overall coefficient of drag appears to reduce as the Reynolds Number increases? I have read that turbulent flows lead to increased skin friction drag, but this is hard to internalize given that the cd is lower overall in turbulent flows for the same angle of attack.

I've been trying to do some research to better understand why aircraft are designed this way, but I haven't had much luck so far. If anyone can offer me some insight here, it would be greatly appreciated!

As an example, I thought it would help to include the drag polar for the NACA 0012, obtained from airfoiltools (http://airfoiltools.com/airfoil/details?airfoil=n0012-il).


texts: How do aircraft engine manufacturers achieve a higher bypass ratio while still meeting the thrust requirements for a given aircraft?

texts: I understand that a higher bypass ratio leads to greater efficiency as less air moves through the core, and therefore less fuel is burned. However, how is the thrust requirement for the same aircraft met with a newer engine that has a higher bypass ratio? Since most of the mass flow will be provided by the front fan, I want to understand what changes are made to turbofan engines that allow the same amount of thrust while minimizing airflow through the core.


texts: What connector standard is used for aviation headsets?

texts:
The typical aviation headset features two cords with connectors that at first glance are identical. One is a standard 1/4" (0.25 inch) stereo audio jack.

What kind of connector is the slightly smaller, slightly narrower one?


texts: How high can I fly a model aircraft under 14 CFR 101 rules?

texts:
For a UAS operated recreationally, may altitude exceed 400 AGL?  AMA rules state in several places that flight above 400 AGL should be avoided. And close to airports there is a more firmly worded restriction. But away from an airport, and presumably in Class G, what are the altitude restrictions?

This question presumes 14 CFR 101 applies.

Addendum to question: FAA appears to be attempting to impose a 400AGL restriction on 101 operations, without regulation. See the amended AC: https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_91-57A_Ch_1.pdf, stating: Model aircraft operators should follow best practices including limiting operations to 400 feet above ground level (AGL).


texts: Is 'bouncing' an airliner on landing in high winds a deliberate technique, or something always unexpected?

texts:
Last week, 767 landing at Newark, high winds, a good deal of rocking in the last few minutes, some passengers quite distressed. The landing was harder and noisier than usual, and we immediately floated upwards, must have been a couple of seconds before we landed again.

The question I have is - in these circumstances (high winds), would the pilots have been flying the landing with a little less flare than usual and anticipating the bounce as a way of shrugging off some speed / energy; or, is it something you never quite know if it's going to happen or not, and would rather didn't happen at all?


texts: Can pilots fly circling approaches at non-towered airports?

texts:
So the answer in my mind is "of course pilots can fly circling approaches at non-towered airports" (seriously, I could swear that I've done it before, but then again I can't think of any specific examples....).

That is, until I ran across this little tidbit in the Air Traffic Control Order while researching another question:

  4-8-6. CIRCLING APPROACH

  a. Circling approach instructions may only be given for aircraft landing at airports with operational control towers.

So then the question becomes, why do they have circling minimums at non-towered airports??

No tower here.
ATC can't clear me to circle.
Why do we have circling minimums??


texts: Is it feasible to circumnavigate the Earth in a sailplane?

texts:
Would it be feasible and survivable to circumnavigate the Earth in a glider or sailplane without propulsion and without landing until the circumnavigation is completed, when you'd return to the same location you were disattached from the carrier plane or winch? What would the major obstacles be and how could one handle it? Did anyone ever attempt such endeavor?
Edit: The two-seated Perlan II sailplane once reached an altitude of more than 70,000 ft (21 km) so perhaps let's discuss more over that single plane, whether the Perlan II, assuming it reaches 70,000 ft, could cross huge areas of sea for instance. If the two pilots manage their time so that one of them navigates while the other sleeps, isn't it likely you could circumnavigate the Earth in the Perlan  II?


texts: Can aircraft ferry engines for other types of aircraft?

texts:
There have been a number of questions that highlighted the fact that the 747 could ferry an engine on an underwing pod.
Was the 747 only capable of ferrying 747 engines? Or was it possible to ferry engines for other types of aircraft?
If it can only ferry 747 engines, is there, or has there ever been, an aircraft that can, and has, ferried engines of other aircraft types?
Edit: Following the comments and the one answer posted to date - ideally, I'm looking for cases of aircraft that can ferry engines externally for other types of aircraft. However, if no such case exists (and I suspect this to be the case), it would be nice to see more comprehensive details of how engines are ferried around the world (I'm sure i.e. Qantas won't always  use sea cargo, nor an An-124 to)


texts: Why do airlines not paint the wings on their livery? Why?

texts: Does anyone know why airlines do not paint the wings on their aircraft? What is the reason why?


texts: Can a 16 year old student pilot "pre-take" the checkride?

texts: I am a student pilot, and I soloed about one month after my 16th birthday. I know I can't become a private pilot until I am 17, but I'm wondering if there is a way to take the check ride before you are 17, but be limited to the privileges of a student pilot until you are 17, at which point you can exercise the privileges of a private pilot? I doubt it, but its worth asking. I feel like I am pretty much ready to take the check ride, but I have to wait 8 more months. Thanks!


texts: Is triskaedekiphobia (fear of the number 13) the reason commercial planes normally do not have a row 13?

texts:
When I first time heard this "legend" I couldn't believe it. I was really surprised, if not shocked, to actually find row 13 missing on my next passenger flight. (I believe it was a Boeing 737.) Is this really due to superstition about the 13th row? Was it so hard to push aircraft producers to renumber all other seat rows?

I know that people can be absurd about their superstitions. But realistically, the odds that a passenger airplane will crash are minimal. And should it really crash, chances that you'll survive due to being seated in row 12 or 14, as opposed to 13, must be below statistical error.

I find it very difficult to believe that people would choose not to fly simply due to superstition about being seated in row 13. Is there a more rational explanation?

EDIT (after Patrick's answer): I don't know, if I expressed myself enough clearly. I don't think, that people are dumb, because the're worried about number 13. I rather think, that thinking, that row 13 is unlucky, specifically on airplanes (where, in case case of crash all seats mostly are equally unlucky) is a bit weird.


texts: What is (or was) the "international frequency"?

texts:
I have recently read a book about Douglas BADER. This pilot has lost his legs (because of accident in 1931) but after (thanks to his single-mindedness) he takes up the "broomstick" again and became a ace with ~30 victory...
After he is shot and captured by the enemy: the Germans. Germans contact the UK in the "International frequency" to send prostheses. The Germans propose a deal but the RAF drops it during a bombing raid with 11 messerschmitt shot in the process.(at the same time)

What information are available about this frequency? (name, usage, frequency).

Have you question about this story?
Bonus :


texts: What is the standard report when pilots exiting and clearing the runway

texts: Let us say I landed on runway 7 and will exit the runway thru taxiway Charlie, is that a standard report like "(Aircraft ID) taxing clear RW7 at Charlie"?


texts: Lapsed Advanced Ground Instructor certificate, can I take a FIRC and and restore my privileges?

texts:
I hold an AGI certificate that I haven't exercised the privileges for in quite some time (more than 12 calendar months).

According to 14 CFR 61.217, can I simply take a Flight Instructor Refresher Course (online or in person) and restore my privileges?

  § 61.217 Recent experience requirements. The holder of a ground
  instructor certificate may not perform the duties of a ground
  instructor unless the person can show that one of the following
  occurred during the preceding 12 calendar months:

  (a) Employment or activity as a ground instructor giving pilot, flight
  instructor, or ground instructor training;

  (b) Employment or activity as a flight instructor giving pilot, flight
  instructor, or ground instructor ground or flight training;

  (c) Completion of an approved flight instructor refresher course and
  receipt of a graduation certificate for that course; or

  (d) An endorsement from an authorized instructor certifying that the
  person has demonstrated knowledge in the subject areas prescribed
  under § 61.213(a)(3) and (a)(4), as appropriate.

It appears so, but I guess at the root of my question is, is it really that simple or did I miss a regulation or sign-off requirement somewhere (I know I could get signed off in leiu of the FIRC).

Then to keep current, what constitutes activity as a ground instructor giving pilot...training?  Just teaching and logging that I've been teaching ground school, or would I actually have had to endorse some people to take the written exam during those 12 calendar months?


texts: Can we fly in Japan and/or Australia with EASA approved training and licences?

texts:
Disclaimer: I'm not a pilot, and seem to be lost with all the jargon and complexities around this matter despite trying to do adequate amount of research.

I am considering taking on my PPL in Hungary and it is all EASA approved training. Thereby the licence will be up to a standard of EASAs approval. Therefore with this licence, would I be able to fly in a foreign country such as Japan, Australia, etc. or other countries with whom EASA has a working arrangement?

If not how would I be able to switch over my PPL to be accepted in Japan and Australia?


texts: How does the F-16 achieve negative stability?

texts:
F-16 has negative stability at subsonic conditions. How is this achieved? To me it looks like a very streamligned, very normally shaped aircraft.
Is the Center of Mass actually behind the Center of Lift? If so, how? I looked up dry engine weight as a fraction of total empty weight, and got 16%. For dry engine weight as a fraction of normal loaded weight, I got 12%.
All the weapons and ammo seem to be ahead of the body or in the middle of the wings or body. So the only thing left is fuel but I cannot imagine how you could fit a large amount of fuel very far aft in that small jet.
Is there some other way it achieves negative stability? How does the F-16 do it?


texts:
Some engines have an exposed tail/exhaust cone at their exit, protruding aft the nozzle.
how does that affect the overall thrust and pressure distribution along the walls of the cone?
is it's role similar to an aerospike?


texts: Have there been instances where a LSA manufacturer has been audited?

texts: In theory, the authority to approve an LSA manufacturer and design has the right to audit their testing and work. What I'm interested in how often does this happen in practice, and whether there have been any cases of violations found because of this. Is the system of trusting manufacturers to be honest with their paperwork working so far?


texts: In what situation could the maximum ramp mass limit the allowed take off mass?

texts: I’ve been pondering this for the longest time, but have been unable to come to a conclusion.


texts: What is the best way to navigate a storm?

texts:
Let me say I had no choice other than fly through a storm I'm on a one way mission to airdrop a vital cure to an isolated area. I can't turn around, land or go around, I have to go through. Going around it means I run out of fuel and they all die.

How does a pilot navigate a thunderstorm? What altitude has the least lightning, wind and hail?


texts: I'm developing a canard glider which requires some taper for the canard to stall first. I understand that sweep is typically only for aircraft in a compressible airflow (M >= 0.3), but is there any benefit to having sweep such that the trailing edge is straight?


texts: Why does the 737NG EGT drop during take-off?

texts: I noticed that the EGT drops a bit when I hit TO/GA for take-off on a 737-800.


texts: How does the Coanda effect help some aircraft produce more lift?

texts:
How exactly does the Coanda effect affect the air stream on the wing of, e.g., an AN-72?

The Coanda effect makes an air stream flow on the curved (outboard) surface object which it has produced from there. How does it help produce lift?


texts: In an unpressurized cabin, why is the cockpit ambient pressure lower than the outside pressure?

texts:
As I study for my IRA written, this (VFR) question resurfaced and continues to irk me. The annotations cite the Venturi effect as the sole reason, but I don't follow.

From Wikipedia: "The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe"

Do we consider the parcel of air in the cabin to be the fluid moving through the constricted section of some imaginary/abstract pipe? If so, why? Can anyone shed more intuition on this?


texts: What exactly distinguishes a beacon light from a strobe light?

texts:
Different sources seem to have different opinions:

Wikipedia: Aircraft warning lights:

  These lights include landing lights, red or white flashing beacons, wingtip strobes, and wingtip navigation lights.

Beacons and strobes are flashing lights.
Beacons may be red or white.
Strobes are wingtip lights. I interpret this as strobes being directional while beacons cover 180°.

Aeronautical Information Manual (AIM), 4−3−23. Use of Aircraft Lights:

  b. An aircraft anti−collision light system can use
  one or more rotating beacons and/or strobe lights, be
  colored either red or white, and have different (higher
  than minimum) intensities when compared to other
  aircraft. Many aircraft have both a rotating beacon
  and a strobe light system.

  d. Prop and jet blast forces generated by large
  aircraft have overturned or damaged several smaller
  aircraft taxiing behind them. To avoid similar results,
  and in the interest of preventing upsets and injuries to
  ground personnel from such forces, the FAA
  recommends that air carriers and commercial
  operators turn on their rotating beacons anytime their
  aircraft engines are in operation.

Beacons are rotating lights. They're always referred as rotating beacons in the AIM.
Both beacons and strobes can be either red or white.
I take the sentence Many aircraft have both a rotating beacon
and a strobe light system. as beacons being the lower intensity lights which are constantly turned on during engine operation signalling the danger of an aircraft in operation, while the strobes being the higher intensity flashing ligths with the reason of being seen from great distance.

Wikipedia: Aviation navigation lights

  Aircraft navigation lights are placed in a way similar to that of marine vessels, with a red navigation light located on the left wingtip leading edge and a green light on the right wingtip leading edge. A white navigation light is as far aft as possible on the tail or each wing tip.[3] High-intensity strobe lights are located on the aircraft to aid in collision avoidance.[4]

  In civil aviation, pilots must keep navigation lights on from sunset to sunrise. High-intensity white strobe lights are part of the anti-collision light system, as well as the red rotating beacon.

  All aircraft built after 11 March 1996 must have an anti-collision light system (strobe lights or rotating beacon) turned on for all flight activities in poor visibility. The anti-collision system is recommended in good visibility, where only strobes and beacon are required. For example, just before pushback, the pilot must keep the beacon lights on to notify ground crews that the engines are about to start. These beacon lights stay on for the duration of the flight. While taxiing, the taxi lights are on. When coming onto the runway, the taxi lights go off and the landing lights and strobes go on. When passing 10,000 feet, the landing lights are no longer required, and the pilot can elect to turn them off. The same cycle in reverse order applies when landing.

Beacons are red rotating lights.
Strobes are high-intensity white lights.
Beacons stay on for the duration of the flight including the whole engine run time.
Strobes are added from takeoff until leaving the runway after landing.

Is there a clear definition?


texts: Is a VOR check required to legally fly an ILS approach under IFR?

texts:
The FARs require a check of the VOR receiver before IFR flight:

§91.171   VOR equipment check for IFR operations.
(a) No person may operate a civil aircraft under IFR using the VOR system of radio navigation unless the VOR equipment of that aircraft

...has been checked using a procedure described immediately following.
Does this apply to an ILS approach? Specifically, consider a flight conducted entirely using GPS, except that it terminates in an ILS approach. In most (or all?) aircraft, the ILS and VOR receivers are one and the same. However, the mechanism of how an ILS and VOR work are very different.
The FARs speak of "the VOR system of radio naviation". Is that specifically for actual VORs, or does it encompass the ILS by virtue of being the same receiver and CDI?


texts: Why can Boeing V-22 Osprey carry more cargo internally than externally?

texts:
According to the Wikipedia, V-22 Osprey can lift 20,000lb of internal cargo, whereas it is able to carry only 15,000lb externally by dual hook.
I wonder why there is a difference between external and internal cargo capacity.
Is it due to the aerodynamics effect of the cargo?


texts: When to log time as PIC, Dual or Co-Pilot?

texts:
I'm currently finishing up my Canadian PPL. I have questions around logging my time appropriately.
Most of it is pretty straight forward. Looking at 401.08 the only thing I'm unsure about is how to log (c) the flight crew position in which the holder acted;

I have a "Pilot Logbook" from VIP Pilot Centre. I'm not using it as I'm maintaining my log online but I use it as a template. It distinguishes between the following three roles: Dual, PIC and Co-Pilot.

Here's how I interpret them:

Dual: during instruction, when CFI is PIC
PIC: student solo flight / solo flight once I hold my PPL

What about Co-Pilot. Is that only relevant when acting as co pilot in an airplane that requires two pilots? What about if, once I have my PPL, I fly around in a C172 with a friend as the PIC, can I log that as Co-Pilot time?


texts: From Facebook video shows a BA aircraft being pushed forward into a hangar. I wonder how it works? Do they rotate nose wheel 180 degree to push it or there is attachment point for the tug to push forward?


texts: Why aren't passengers instructed how to lift aisle armrests?

texts:
Only when I chanced on this /r/LifeProTips post, did I know

  Most airplane aisle seats have a small lever or button on the underside of the armrest, near the hinge. Pushing or sliding this lever will release the hinge lock, allowing you to raise the armrest.

When horizontal and down, aisle armrests  obviously hinders exit during emergencies when  saving seconds can save lives, especially for more obese passengers. So why isn't this hidden button/lever disclosed to passengers, like in the mandatory safety briefing or video?

I'm not asking about armrests between seats that don't require a hidden switch to lift.


texts: Is there any bibliography for triplane aircraft design?

texts:
I've been tasked with designing an RC aircraft that has the greatest lift force for a specified wingspan, total length and takeoff velocity, and thus have been studying the different wing configurations that could be used.

I've had ease in finding methods for designing more common configurations (using books such as Snorri Gudmundsson's and Jan Roskam's), even biplanes, however it seems there is no method specialized for estimating the aerodynamic coefficients for triplanes, which to me seems to be a very promising way to increase wing area with the given geometrical constraints. There are methods for biplanes such as Munk's General Biplane Theory, but not triplanes.

I've managed to use the XFLR5 software for simulating the configuration (wings and vertical stabilizer only, though - I've had to use the elevator as the third wing). However, I've learned it's not good practice to rely solely on a single method's results for obtaining the aerodynamic coefficients, and without some sort of semi-empirical method to compare it against, I'll unfortunately have to scrap that possibility.

If there are no such equations, can the biplane methodology be adapted in any way for a triplane? I've found two NACA reports comparing biplane and triplane wind tunnel results, but haven't managed to fiddle with the biplane equations and get accurate results from them.


texts: Is it required to memorize checklists for better efficiency?

texts:
Military pilots are instructed throughout training that they must learn all checklists off-by-heart (in the RAF anyway). This way things get done much quicker, primarily in the event of an emergency when the immediate actions must be performed like 2nd nature.

A recently PPL-qualified pilot friend of mine informed me that he refers to his reference cards for every set of checks. The checks for a Cessna-152 were much much more brief than for military trainers.

I was wondering what the standard is for general aviation, and whether there is a requirement to learn at least engine-failure immediate actions?


texts: How far in advance of "effective date" are VFR sectional charts usually made available? (US)

texts:
In the US, how far in advance of the "effective date" are new editions of VFR sectional charts usually made available?  Is the answer different for the paper version and the digital version?
Were some or all of the 2-25-2021 editions of the VFR sectional charts for US airspace released (i.e. made available) with much less "lead time" than usual?
The 2-25-21 version of the Juneau VFR sectional chart became available for downloading from the FAA's "VFR Raster Charts" web page sometime between February 3 and February 15.  Is this less "lead time" than normal?
As of today, March 1 2021, the vfrmaps.com image for Sitka Alaska (SIT/PASI) still shows the old airspace configuration, which is no longer current, due to a change published July 31 2020 and effective November 5 2020.  Here's what vfrmaps.com shows (clipped from a screenshot from this url accessed through this airnav.com link for the Sitka airport, SIT/PASI).

And here's what the airspace actually looks like, taken from a screenshot of the PDF version of the 2-25-21 Juneau sectional chart, downloaded from FAA's "VFR Raster Charts" web page-

Is it unusual for the vfrmaps.com product to still show the image from the previous edition of a VFR sectional chart, several days after the new edition has gone into effect?
And if so, is this likely related to the charts being released with less "lead time" than usual?
And if so, do similar discrepancies between commercially available on-line map products and the actual FAA charts exist in other regions of the US at present, for the same reason?
This question is not about why there were no new editions of the Juneau sectional chart issued between March 26, 2020 and February 25, 2021.  That question is asked here: Were planned release dates skipped in 2020 for the VFR sectional charts for Juneau Alaska and Dutch Harbor Alaska?


texts: When must delegated airspace be listed in the AIP?

texts:
Two states can agree, through a bilateral letter of agreement, to delegate the responsibility for providing air traffic services (ATS) within a certain airspace from one state to the other. There can be numerous reasons for this. For example, a part of Scottish airspace is delegated to the Danish air navigation service provider (ANSP), because Denmark has better radar coverage within the specific area. In this area, which is within Scottish airspace, ATS is provided by the Danish ANSP.

My question is regarding the need to publish details about such airspace delegations in the national aeronautical information publications (AIP).

The previously mentioned delegated airspace is described in AIP Denmark section ENR 2.2 (Other regulated airspace). However, a part of German airspace within Hannover upper flight information region (UIR) is also delegated to Denmark, but this airspace is not shown anywhere in the AIP. To me, this seems very inconsistent, which brings me to my question: under which circumstances are states required to publish information about delegation of ATS? I am interested in references to ICAO SARPs or PANS, or, alternatively, EU regulations.

The below chart (AIP Denmark ENR 6.2 – 1) clearly indicates some delegated areas in Scottish airspace and around the border to Sweden (which I have marked with blue), but, the delegated area in Germany (which I have marked with red) is not shown.

The area is, however, shown on this "Sector Boundary Structure Chart" chart published by Eurocontrol:

I have looked in ICAO Annex 4 and Annex 15 without any luck.
Appendix 1 of Annex 15 states that:

ENR 2.1 shall contain, among other things:

  Detailed description of flight information regions (FIR), upper flight information regions (UIR), and terminal control areas (TMA), including:
  (…)
  2) identification of unit providing the service;
  (…)

I usually see delegated airspaces listed in ENR 2.2, though, so they do not seem to need to be covered in ENR 2.1.

ENR 2.2 shall contain:

  Where established, a detailed description of other types of regulated airspace and airspace classification.

It is not specified exactly what this includes.


texts: How can I keep the data on a KLN89b GPS up to date?

texts:
I'm looking at a Mooney M20C with a pretty dated panel, but it's airworthy and could be a great opportunity to build some retrac time. The KLN89b GPS is IFR Certified, but is positively ancient.

There seems to be a convoluted process to keep it up to date. I don't know if the present owner has the cable or the proprietary card reader. I've found some on eBay that seem to be for the KLN94 so I'm not sure if they will work with the KLN89b.

In my club we have a C172 with a GNS430 that has a fairly straightforward update process. I'm hoping the KLN89b is pretty similar if I get the card reader. I certainly don't want to take the entire GPS out of the aircraft and load it into a docking station every month.

If anyone can share their experience with this unit that would be great.


texts: What does this plus (cross) sign on this electrical panel mean?

texts: I'm looking at a picture of the electrical panel of a Phenom 100 and on it I see a + sign, does anyone have any ideas as to what it's supposed to mean?


texts: Does SDAC display data for both the PFD, ND and the ECAM display?

texts:
On the Airbus A320 the System Data Acquisition Concentrators (SDAC) aquire system data, process it and sends system page data to the three Display Management Computers (DMC). The DMC process the data and generate an image.

Is this for the PFD and ND only? Or does the DMC also generate the image for the upper and lower ECAM too?

EIS, source

If the lower ECAM, supplied by DMC 2, fails then the E/WD displays which has priority take its place; and DMC 1 normally supplies the Engine/Warning Display (E/WD).

Does it mean DMC 1 has a channel or a way to display on the lower ECAM as it just did?
Likewise, does DMC 2, which normally supplies the lower ECAM, have a channel or some sort of way to display on the upper ECAM?


texts: In turboprops, is there a mechanism to prevent the blades running in opposite direction?

texts:
Because, it might lead to reverse flow of air and could stall the plane. Is there some mechanism to prevent this?

There was a crash in Ireland a few years ago, when the pilot of a small charter plane accidentally put one of the turboprop's in reverse.


texts: As a Brazilian pilot, can I buy an aircraft in the US then fly it to Brazil to register it?

texts:
I have a pilot license in Brazil and would like to purchase an aircraft in the US and then register it in my country.

My license allows me to fly the aircraft back to my country?


texts: What is the relationship between EGT, Fuel Flow, N1, N2 and Air Temperature?

texts:
I initially wanted some sample data for EGT, Fuel Flow, N1 and N2 to build a prognosis system that predicts engine failure (ECTM).
I searched for some sample data online but got to know that there's virtually no way of acquiring that. (Where can I find sample data required for Engine Condition Monitoring?)

Now, I have to generate my own data for this. It is crucial for me to understand the relationship between the 5 important parameters that I'm taking into consideration.

Parameters are EGT, Fuel Flow, N1, N2 and Air Temperature.

For now, I've understood this:

Temperature increases, EGT increases.
Temperature increases, Fuel Flow increases.
N2 decreases, Fuel Flow increases. (src - What does it mean for N1/N2 to float?)

Can you guys please give me more insight like the ones above? Also, please correct my mistakes. I'm a computer science student and this is all very new to me.


texts: How to maintain your pitch when looking for other traffic in the pattern?

texts: I am a student pilot and I fly in a desert region where turbulence often changes the pitch and airspeed of my aircraft.  I am having an issue maintaining pitch while scanning for other aircraft in the traffic pattern (I lose sight of the horizon while scanning).  I might scan for 2-3 seconds and by the time I bring my eyes back to the horizon my pitch has changed 10 degrees and I have lost 5 knots of airspeed.  My flight instructor then scolds me for not holding my airspeed.  Is there a way to scan for traffic while still maintaining reference to the horizon?


texts: What is the influence of yaw on P-factor?

texts:
From William Kershner's “The Advanced Pilot’s Flight Manual”- page 2-17, P-Factor:

If the airplane is yawed, the P-factor effect is encountered. A left
yaw would mean a slight nose down tendency and a right yaw a slight
nose up tendency (you can reason this out).

Unfortunately, I couldn’t reason this out :(
Anyone care to explain?
Thanks!


texts: What is an Enhanced surveillance system?

texts: What is the purpose of enhanced surveillance system and what are the benefits of installing it? And what information is available from this system?


texts:
Is it possible for  control surface flutter  to occur at low Reynolds and low speed?
If yes,why don't Ultralights have counter weights or tail sting mass to immune the control surfaces against flutter just like how most G.A planes and aerobatic planes do?


texts: Compression and tension members of a biplane wing

texts: I get why the upper wing of a biplane is a compression member (because the flying wire is attached to it at an angle) but what I fail to understand is why the lower wing is the tension member of a truss of a biplane as explained here. So my question is why is the lower wing of a biplane referred to as a tension member of a struss?


texts: How does a small aircraft like a Cessna fly at night?

texts: What happens when a small aircraft like Cessna is flying in daytime then night hits and its now pitch black with zero visibility? How does he not run into mountains and the like?


texts: What does it mean "two plane thrust vectoring nozzle"?

texts: It has been said that only Sukhoi 35 has the "two plane TVN" others like F 22 and Su 30MKI (produced by India under license at Hindustan Aeronautics Limited)  have "one plane TVN".So what the difference ?


texts: What are the numbers in boxes on an A320 ND when terrain is shown?

texts:
When the TERR On ND button is pressed on the Airbus A320 Cockpit, the TERR information apears on the ND, and 2 boxes in yellow appear.

What do the numbers 146 and 073 mean respectively?


texts: What is the difference between Full Throttle Height and Critical Altitude?

texts:
My understanding is that "critical altitude" is the density altitude at which the wastegate on a turbocharged engine is fully closed, so any climb will result in a decrease in manifold pressure.
Is this different to "full throttle height"? I have heard conflicting definitions of that, such as it only applies to superchargers, or that turbocharges have multiple full throttle heights.


texts: Should operations such as landings or approaches be logged when acting as pilot monitoring?

texts:
When operating aircraft that require two crew members, generally one pilot acts as PF (pilot flying) and the other as PM (pilot monitoring). How should operations such as landings and approaches be logged when acting as PM?

Is there any guidance on this for pilots operating under the FAA?


texts: Why is the generator turned back off for starting the second engine on a King Air?

texts:
The engine start procedure for the Beechcraft King Air B200 says (emphasis mine):

  Right Ignition and Engine Start Switch – ON [R FUEL PRESS] annunciator – OFF
  Right Condition Lever – LOW IDLE (after N1 rpm stabilizes; 12% minimum)
  ITT and N1 – MONITOR (1000 oC maximum)
  Right Oil Pressure – CHECK
  Right Condition Lever – HIGH IDLE
  Right Ignition and Engine Start Switch – OFF (at 50% N1 or above)
  Right Generator – RESET, then ON. CHARGE BATTERY until loadmeter reads approximately .50, then OFF
  Left Ignition and Engine Start Switch – ON [L FUEL PRESS] annunciator – OFF
  As Left N1 RPM accelerates through 12%:

  Left Condition Lever – LOW IDLE
  Right Generator – RESET, then ON

  ITT and N1 – MONITOR (1000 oC maximum)
  Left Oil Pressure – CHECK
  Left Ignition and Engine Start Switch – OFF (at 50% N1 or above)
  Left Generator – RESET, then ON
  Right N1 – REDUCE TO LOW IDLE

Why is the right engine's generator turned back off before starting the second engine (step 7) and then only turned on again after injecting fuel (step 9)? Doesn't this put unnecessary load on the battery?


texts: Why is the angle of attack not proportional to the stagnation point?

texts:
While I was studying my PPL today, I've encountered a question right below and I wasn't really satisfied with the answer.

Which statement about the airflow around an aerofoil is correct if the angle of attack increases?

The stagnation point moves up
The stagnation point moves down (correct answer)
The center of pressure moves down
The center of pressure moves up

Up here, α is the degree between the chord line and the oncoming airflow.

1) Stagnation point

2) Transition point

3) Transition point

4) Separation point

So, knowing all of these facts I just can't understand the question above. Why is the stagnation point moves down instead of going up while increasing the angle of attack?


texts: What is the difference between Turn Coordinator and Artificial Horizon?

texts:
I was reading this question about Turn Coordinator and Artificial Horizon, and now I want to understand the differences between those two components.

What is the main difference between Turn Coordinator and Artificial Horizon?

Turn Coordinator:

Artificial Horizon:


texts: What is physics explanation for minimum sink rate airspeed?

texts:
I did some research on Minimum Sink Rate, and saw much information defining it, (such as it is the speed at which the aircraft will remain in the air for the longest time, etc.) and how it is generally lower than Best Glide speed, and is generally a few knots above stall speed. There was also some information about what is used for (when you are trying to remain airborne for as long as possible after engine failure in order to deal with an emergency, or for gliders to maximize the climb effect from a thermal),

…. But I could not find, anywhere, an analysis/explanation for how this works, from a Physics perspective, as you can easily find to explain Vx, (best angle of Climb airspeed), and Vy (best rate of climb airspeed), that explain/analyze them from a Physics perspective (Vx is speed at which you have the highest Excess Thrust, whereas Vy is the speed at which you have Maximum Excess Power).

Also, from my limited understanding, what I did read seems to violate my basic understanding of what Min Sink Rate means, from a Physics Perspective. As I would understand it, Min Sink Rate Speed is the speed at which your rate of descent is the lowest, (you will remain airborne for the greatest amount of time). This is equivalent to the airspeed at which the aircraft is losing altitude, (Potential Energy), at the slowest possible rate. With no power on the aircraft, loss of energy (altitude) is directly related to total drag, (energy must be conserved!), and this occurs at L/Dmax.  All the complexities involved with determining Maximum Excess Power, or Maximum Excess Thrust, as are required to analyze Vx and Vy, become moot.  So although it appears to be accepted wisdom that Minimum sink is different from Best Glide, this seems to violate basic physics. They should both occur at the airspeed (AOA actually) where total Drag is minimized, i.e., at L/Dmax. Where am I going wrong?


texts: How is the wind direction and wind speed measured in flight?

texts:
Most large aircraft have a wind direction and wind speed indicator. How is this measured? The vector difference between TAS and ground speed? How accurate is this?

In the below picture (taken from this question) it is displayed in the top-left corner of the top-right quadrant (just below the TAS and GS).


texts: Is there any limit on how narrow aisles can be?

texts:
Sometimes, when I'm flying on the airlines, I'll board an aircraft where the aisles seem incredibly cramped, where it's almost impossible to move past without bumping every seat. I can't imagine how much of a nuisance it'd be for people larger than me! I once saw an obese person a bit stuck between one of the aisles, blocking the way for others to move into the aircraft.

But then I thought about what would happen in an emergency. What if there were numerous large people on board, and there was a fire?

So, are there any limits to how much the airlines can squeeze their planes' aisles?


texts: Where can one access the electrical buses in an aircraft?

texts:
I am looking at how new systems are retrofitted in aircrafts (large business jets or airliners), and I was wondering where the mechanics can get access to electrical power.

More specifically, I know that there is an electrical cabinet close to the cockpit, but are there any accessible AC buses elsewhere in the aircraft (for example, so that you don't have to run wires all the way back if you install something near the empennage)?

Thanks for your help!


texts: Why is a right pattern the standard for a hold?

texts: Why are right turns the standard hold turning direction?  Why not left?  Is there a reason or is it arbitrary?


texts:
In looking at Garmin Pilot, there is something labeled "Vancouver FIR" which has 3 segments. It's located over the northern Cascades and to the east of the northern tip of Vancouver Island (Canada). What is that "Vancouver FIR"?

Specifically, I'm interested in flying over those mountains at a few thousand feet AGL (in and among the mountains) and am wondering if this "Vancouver FIR" is something I need to worry about.

I'm currently working on obtaining my Private Pilot Certificate in the United States.


texts: How can a headset cause continuous transmission (PTT blocked)?

texts:
I own three aviation headsets:
- BOSE A20
- David Clark H10-13.4
- Compilot Lite (a cheap headset bought recently, for occasional use by passengers)

I tested the Compilot Lite last week (co-pilot side), but I ended up blocking the frequency at a local airport. Unfortunately, it took me some time, and somebody waving furiously at me, before I found out.

I was wondering how this issue could occur and what could be wrong with the headset. I found an explanation on this forum, which states that the tip of the connector functions as a PTT button when grounded. However, the connector does not seem to differ a lot from the other headsets.
Left = Compilot, middle = DC, right = Bose.

Could it be caused by something else? The type of microphone?

Any tips or suggestions are welcome.

Thanks!
David

PS the aircraft was a C172N, a rental which I often use, but never had this issue before with the other headsets


texts: How close can separation be during a landing clearance?

texts:
How close can separation between two aircraft be during landing? during visual landing clearance?

Specifically, I refer to this Aviation Herald Report where:

  When the Boeing 777-300 was about 2.1nm before touch down a BAe Avro
  began its takeoff run on runway 08R. The Boeing 777 was subsequently
  cleared to land on runway 08R, winds from 130 degrees at 7 knots.

  When the Boeing 777-300 crossed the runway threshold, the Jumbolino
  was climbing out still short of the runway end.

(Source: www.avherald.com - Singapore B773 at Munich on Nov 3rd 2011, runway excursion)

Is it typical for two aircraft to be so close during landing? i.e. Essentially both landing & departing aircraft are simultaneously overflying the same runway but at opposite ends.

How much closer would cause the landing aircraft to abort? Would one proceed with landing even if when one crossed the threshold the other craft was just rotating?

There's other things that went wrong in that incident,  but I'm only asking about the close separation in the landing clearance visual clearance aspect.

PS. I've edited the question to remove a confusing misunderstanding. It was apparently not a visual clearance.


texts: what would happen if we use needle shaped nose in blended wing?

texts: We are using blunt shaped nose in blended wing,instead of blunt,if we use needle shaped nose what would happen ,it reduce shockwave or it produce bow shock?


texts: Are 360s by a B777 common in the holding pattern?

texts:
I found this forum having tried to find the answer on Google. I was on a B777 coming into Heathrow from Miami yesterday (AA56) and was expecting us to go into the usual hold. The attached picture showed we did ultimately do that but not after making a seriously tight circle. I thought at the time this was unusual in such a big plane so looked it upon flightradar (link below) and you can see just how sharp it was. Is this normal? I'm not the best flier so was pretty freaked out. I'm sure it's fairly common but I have never experienced anything like it, short or long haul.

https://www.flightradar24.com/data/flights/aa56#1069b0be


texts: Why is the bypass ratio of a turboprop higher than turbofan?

texts:
Whenever, I come across turboprop, the author always mentions that they have higher bypass ratio than turbofan but no one explains the reason for this.

So, is the bypass ratio higher due to higher disc radius of turboprop or is it due to less air flow through the core or the combination of both?

If it is only due to less air flow inside the core, then they can still have a higher bypass ratio in turbofan right? (Since advanced turbofan produce less noise due to the nacelle)


texts:
What is this pattern on this runway? What is its function?

Location on Google Maps


texts: I am a computer programmer and student pilot. I want to make a computer program I can use to store my logs. Can I legally do this? Can I legally store Logbook endorsements with this? Are there any rules I need to be aware of? For the signatures can I use a pilot's certificate number instead?


texts: Where is the inclinometer "ball" in a knife edged turn?

texts:
Discussion of steep turns has lead to a question about where the inclinometer ball would be
if the plane rolled to 90 degrees.  Also, would there be any difference if the plane simply rolled to 90 degrees, rolled to 90 degrees and maintained altitude in a straight path with rudder, or rolled to 90 degrees and executed a "knife edged turn?

Does the ball become irrelevant at these attitudes?


texts: Is there a graph that shows the thrust required for a given airspeed?

texts: I would like to see the graphical relationship between thrust required and airspeed for a typical general aviation aircraft, e.g. C-150 or C172 series.


texts: What is the difference between a navigation database and an airport mapping database?

texts: What is the difference between "navigation database" and "airport mapping database"? Are those both required by flight management software for flight planning?


texts: Can a software "hard freeze" or serious hardware problem completely disable the whole cockpit?

texts:
I think that the glass cockpit of a modern plane has some sort of a central power supply or at least some central controlling software.

What happens if this central power suddenly disappears, or the central software freezes? Yes, of course, this would be a severe failure and would put everybody's life on the plane in serious danger.

Is such a failure possible?


texts: What percentage of airplanes are involved in a crash in their lifetime?

texts:
The chances of a commercial flight crash are about 1 in 1,200,000 - pretty low. If each plane makes about 40,000 flights in it's lifetime, about 1 in 30 airplanes will be involved in a crash before it reaches retirement.
Is this an accurate estimate? 1 in 30 seems like quite a large amount of airplanes to crash before they are retired.
I'm also assuming here that after a crash an airplane is written off. This may not be the case - I don't know how much a plane can be repaired.


texts: How to justify that M_AC=0 for a symmetric airfoil?

texts:
I learnt that for a symmetric airfoil, the pitch moment around the aerodynamic center should be null:

$$M_{AC}=0$$
$\hspace{11pt}$ How could I intuitively explain this statement?

I also learnt that for an airfoil with positive curvature, $M_{AC}<0$ and  for an airfoil with negative curvature, $M_{AC}>0$. I'm new at my Flight Stability course, and I don't know how to achieve these conclusions. I do know the definition of aerodynamic center, but it isn't enough for me to make such observations.
How could I deduce these statements?


texts:
In order to help ATC identify an aircraft on their screen, they may ask the aircraft to "ident." The pilot presses a button on their transponder, and the controller can verify that the aircraft they are talking to is the one they are looking at on the screen.

In what situations does ATC ask for ident, and is it ever required by procedure?
What does the transponder actually do in this mode?
What does the controller see on their screen?
Does it depend at all on either the code or the mode the transponder is currently set for?


texts: Forces "felt" by pilot, G-meter, inclinometer--are they the aerodynamic forces generated by the aircraft, or the sum of weight+centrifugal force?

texts:
Consider a pilot sitting at the CG of an aircraft, with instruments also located at the CG of the aircraft.  (Feel free to consider other cases as a bonus, but the core of the question is aimed at this simple case.)

Consider the apparent force "felt" by the pilot, and measured by a traditional-style panel-mounted G-meter, when the aircraft is upside-down at the top of a loop.  Should this force considered to simply be an expression of the wing's lift vector, plus any other aerodynamic force components that the aircraft is generating?  Does gravity make a contribution to this force?  Does "centrifugal force" make a contribution to this force?  Is the force "felt" by the pilot, and the G-meter, due to the combined effects of gravity and "centrifugal force"?  Can more than one of these things be true at the same time?

Consider the apparent force "felt" by the pilot, and determining the deflection of the inclinometer (slip-skid ball), during a coordinated turn, or during an uncoordinated turn.  Is this force simply an expression of the net aerodynamic force generated by the aircraft?  Does gravity make a contribution to this force?  Does "centrifugal force" make a contribution to this force?  Is the force "felt" by the pilot, and the inclinometer, due to the combined effects of gravity and "centrifugal force"?  Can more than one of these things be true at the same time?

Feel free to substitute "acceleration" for "force" in your reading of the question, if you feel it makes it a better question.

Basically this question is seeking to reconcile the view that a pilot only "feels" the aerodynamic force generated by an aircraft, and the view that gravity and / or centrifugal force also play a role in the forces "felt" in flight.  Can these two views be reconciled?  If so, how?  Or is only one of these two views correct?

A thought problem might that better inform the question -- consider an astronaut in orbit.  Is he or she feeling both centrifugal force and gravity?  Or neither?  Or is this purely a manner of convention, i.e. either answer is accurate?


texts: What do the pointers on a Kollsman altimeter indicate?

texts:
In this thread: What type of altimeter is this?

there are 3 images of altimeters that have a pointer that moves around the outside diameter of the scale markings and they have another pointer that moves around the inside diameter of the scale markings, e.g 4 and 5 on this picture.

(Source)

What is the purpose of the triangles (4 and 5)?
What are the units or multiples used?

If possible, please give an example of what one of these is indicating. I mean like: so many feet of some kind of altitude.


texts: By what angle does the rotor disc change with max. cyclic input?

texts:
If maximum longitudinal/lateral cyclic blade pitch input is given, by how many degrees does the thrust vector (or rotor disc) change? Is the magnitude in the order of $\pm5^\circ$ or more in the order of $\pm15^\circ$?

Can this be assumed to be the same as the maximum blade flapping angle?


texts: Are large passenger aircraft steered during taxi by changing the angle of the front landing gear?

texts: When moving to and from the runway, does a large passenger aircraft turn by changing the thrust difference on its side engines, or by turning the front landing gear to a different angle? If it is by turning the front landing gear, through what device does the pilot control the angle?


texts:
KDEN is currently reporting the following METAR:

SPECI KDEN 090325Z 34031G37KT 10SM -PLRA FEW015 OVC036 08/03 A2992 RMK AO2 PK WND 35037/0325 RAB04PLB25 TS DSPTD P0000 T00830028 $

I have no idea what DSPTD stands for. My best guess is "dissipated". I have been unable to find anything online, can someone help confirm this?


texts: What criteria are used for exiting an airplane in an emergency?

texts: I often see after a crash that people die unable to exit the aircraft. The news reports and passenger and safety organizations criticize the FAA for not having realistic emergency exit regulations. What determines the criteria for a plane being "safe" in an emergency?


texts: Should you sump fuel tanks when the fuel system is below freezing?

texts:
I recently saw an argument in a forum I frequent that sumping the tanks when the system was below freezing was a bad idea, as you can't drain solid ice from the fuel system, and there is a chance that ice may jam the drain open, causing your entire tank of avgas to empty onto the ramp.

While this is certainly a possibility, is it a reason to skip sumping the fuel system during preflight, or do the reasons for checking the fuel system outweigh the risk of a tank of fuel winding up on the ground?


texts: How are this helicopter's blades perfectly timed with the camera shutter?

texts:
This is a video of the Mi-24 helicopter. The rotor blades appear not to be moving.
Did the pilot and photographer sync the camera and helicopter to make this video and how? I do not know the true source but the video is remarkable.


texts: Calculating lift with lifting-line theory in MATLAB

texts:
I am attempting to calculate the lift generated by a model wing (~0.8$m^2$ wing area) using Prandtl's lifting-line theory in MATLAB. I am starting with the equation below from Anderson's 2005 book Fundamentals of Aerodynamics:

I have defined the $\frac{2b}{\pi c(\theta)}$ as '$\mu$' for simplicity, moved this back into the first summation and rearranged the above to:

$\Sigma A_n\sin(n\theta)(\mu + \frac{n}{sin(\theta)}) = \alpha(\theta) - \alpha_0(\theta)$

Presumably if I split the half-wing section (i.e from $\theta = \pi/2$ to $\pi$) into 10 segments I can generate a set of simultaneous equations from $n = 1$ to $10$ and $\theta_1$ to $\theta_{10}$. Solving that set of equations should then give me values of $A_1$ through to $A_{10}$. However, the values I'm generating for my coefficient matrix, $B$, (i.e. the $\sin(n\theta)(\mu...)$ bit) seem to be off, reaching 65 for $\theta_1$ and $n =10$. This is turn gives me incorrect values of the $A$ coefficients. Both are shown below:

This leads me to believe something must be off in either my re-arrangement above or my MATLAB code, which is shown below for completeness. It might be inefficient but please ignore that for now! Anyone able to assist with where I might be going wrong? Would be greatly appreciated!

MATLAB Code:

clear all
clc

% Wing segments:
N_seg = 10;
N_seg2 = N_seg;

% Flow:
U_0 = 15.433 % [m/s]
sweep = deg2rad(30); % Sweep angle
U_n = U_0 * cos(sweep); % Flow component travelling normal to wing sweep

% AoA and zero-lift AoA:
AoA = 0;
AoA_0 = -6.4;

% Wing twist, to be confirmed following further design:
twist = 0;

% Initiliase segment chord, theta and AoA matrix:
c = zeros(1,N_seg);
theta = zeros(1,N_seg);
AoA_seg = zeros(1,N_seg);

% Lambda range:
for Lambda = 0.25:0.25:0.5

% Wing area, span, chord etc.
S = 0.8; % [m^2], wing area
b = 1.56827; % Wing span
s = b/2; % Semi-wing span
c_root = (2*S) / ((1 + Lambda) * b); % root chord [m]

c(1) = c_root; % setting root chord as inner segment wing chord
theta(1) = pi/2;
AoA_seg(1) = AoA;

% tip chord [m]
c_tip = ((2*S) / ((1 + Lambda) * b)) * (1 - ((2* (1 - Lambda)) / b) * (b/2) );
% mean aerodynamic chord [m]
MAC = (2/3) * (c_root + c_tip - (c_root * c_tip) / (c_root + c_tip))

    % Segment chord lengths and theta to wing tip:
    for N_seg = 2:N_seg
        % Chord length of each segment, linear interpolation
        c(N_seg) = c_root + (c_tip - c_root)/N_seg2 .* N_seg
        % Theta of each segment;- first segment must not be 0,
        % otherwise singular matrix obtained
        theta = pi/(2*N_seg):pi/(2*N_seg):pi/2;

        % AoA of each segment , linear interpolation
        AoA_seg(N_seg) = AoA + (twist)/N_seg2 .* N_seg
    end
    mu = 2*b./(pi*c);

    % Setting up RHS (B) and LHS matrix:
    for i = 1:N_seg
        for j = 1:N_seg
            B(i,j) = (sin(j .* theta(i))) .* (mu(i) + j/(sin(theta(i))))
        end
    LHS(i) = (AoA_seg(i) - AoA_0) * (pi/180);
    end

    % Finding A coefficients:

    A = B\transpose(LHS)

end


texts: What are the consequences of hail damage to a small GA plane?

texts:
I recently found a Cessna 172 that had been totaled by the insurance company because of hail damage.

The PDF from that page has detailed pictures which show hail-divots all over the the wings, body and empennage.

Can the plane still fly like this?

What effect is this likely to have on the flight characteristic of the plane?


texts: Why does an aircraft not spin out of control right after touch-down?

texts:
When a plane is landing, how does it not immediately start spinning out of control?

Given the massive amount of forward momentum and the fact that all the various braking forces (wheel brakes, spoilers, thrust reversers) are applied separately on each side of the plane, if there was even a small imbalance between the two sides wouldn't the plane want to start spinning (yawing) in that direction?

Is this something a pilot has to account for while landing or is there some physical effect that makes it Just Work?


texts: Using a standard PC gaming / smartphone headset for passengers in a small plane

texts:
There is a very similar question to this, but all answers and discussion pertain to just the PC headphones, and not headsets (the headphones with microphones). Gaming headsets have a boom mic and cable with dual connectors (pink/green), both 3.5mm, one stereo (for headphones), the other mono (for the mic). Standard smartphone headsets have a mic on the cable and a single 3.5mm TRRS (tip-ring-ring-sleeve) combo connector. There are plenty cheap ones with active noise reduction, decent audio quality on both headphones and mics, and more importantly, many people already have them. There are also plenty of Bluetooth headsets (with mics).
A possible solution would be building a Bluetooth adaptor that could plug into the intercom, and then pair with the passenger’s headset to allow them to communicate with others. Bluetooth frequencies are well outside the range of any of the nav/com systems, and even so, they would give the pilot a good excuse to avoid passenger distractions during departure /approach (by turning the Bluetooth transceivers off). Resourceful home builders could easily get the necessary electronics for the Bluetooth transceiver (and adjust the impedance as needed).
If the mic (and headphone) impedances are reasonably close, wouldn’t a simple cable adapter be all that’s needed to enable connection?


texts: Is there a minimum separation between a landing aircraft and another crossing its runway?

texts:
I have just seen this video of what has been called a runway incursion at LEBL (my hometown airport). A russian jet initiates a go-around after seeing an argentinian plane crossing runway 02:

https://www.youtube.com/watch?v=1N5THRSp4hM

It's not clear (as of 2014-07-07 1400L) whether ATC gave clearance to cross the runway. Anyway, my understanding is that even with ATC clearance you are required to check for incoming traffic and hold short of the runway if such traffic exists.

Seems like the taxiing crew either didn't look for incoming aircraft or they estimated they had enough separation to cross the runway.

So, is there any regulated separation distance (time/space) that can be used to tell who was responsible for this conflict? It's solely based on pilots' criteria?


texts: How does email communication with a private pilot affect FAA rules on compensation?

texts:
If a person exchanges email with a private pilot (who normally operates under FAR 91) with a view towards hitching a ride or taking an empty leg flight, does this act mean that the pilot must then operate under FAR 135?

Or alternatively, if there is no discussion of payment and/or barter, would the ride still take place under FAR 91?  I have watched the demise of AirPooler, but this was a much more structured arrangement which blatantly  invited scrutiny from the regulator.  This question assumes there is no intermediary like AirPooler or BlackJet.

I am trying to find out what actually triggers an escalation in the rules.  FAA would be fine, but anything on European regulators would be massively welcomed.  I am UK based, not a pilot, and use empty leg on occasion, so I might be affected if the European regulators follow the FAA's lead.  Knowing the trigger point is key.


texts: Why would banking be a problem for passengers on the Flying-V aircraft?

texts:
In this article, the author raises doubts about the viability of this aircraft:

  Sadly for the Flying-V, it will probably fail like the blended wing
  body designs we've seen down the years. It's for the same reason, too:
  airplanes bank as they turn. That's not much of a problem in a
  conventional airliner design, where passengers are never that far from
  the plane's central axis. But as you move further out from that
  central axis the effect becomes a lot more pronounced.

credit: Edwin Wallet, Studio OSO

I don't really understand how banking is a problem. The angle for the passenger remains the same, the only difference being an increased of vertical acceleration when the airplane is initiating / retracting the bank.

An apparent simple solution would be to... bank more slowly...

Is there something I'm missing?
Would the vertical acceleration really be a concern for passengers?


texts: Do pilots ever increase the cabin altitude intentionally?

texts: Is it true that some pilots increase the cabin altitude slightly to calm down potentially disruptive passengers for safety reasons? For example, footballers who have just won a championship.


texts: Is it possible to create a direct supersonic airflow to a turbofan's afterburner in order to enhance the performance or reduce the fuel consumption?

texts: so I found out that SR-71 Blackbird is using what's called "turboramjet" and I find the idea a bit appealing since they say with such engine, the Blackbird is more fuel efficient at it's top speed. I know that the mechanism for such engine is extremely complicated, but what's on my mind is not making an engine like Blackbird's, more to the point of having a direct supersonic fresh airflow to the afterburner to keep the fuel consumption slightly lower thanks to more oxygen to keep the afterburner effectively burn(because I heard somehwhere afterburners burns 3 times more fuel than dry thrust, I hope this can reduce it to only twice or even 1.5 times original dry thrust fuel consumption and have the same performance). Is it possible to do such thing? what would be the main problem to such engine/design? can it produce more thrust/more efficient in fuel consumption? and for the sake of calculations, let's say the turbofan engine in question is GE F-414-EPE, on afterburner, in supersonic speed.


texts: Can old passenger airplanes be refitted with latest engines to extend their life and efficiency?

texts: I was wondering if this might make sense as commercial aircraft design has not changed significantly (from the outside) in the last 50 years?


texts: Are aircraft with counter-rotating props or Down Between Engines less likely to develop asymmetric icing?

texts:
It is suggested by some (and somewhat substantiated) that twin-engine propeller aircraft which do not have counter-rotating props (all modern regional turboprops are this way) can develop asymmetric wing icing due to the airflow pattern generated by the propellers:

 (from the FAA FFFSCR report, via the linked source)

Has it been demonstrated that twins with counter-rotating props (are any such twins rated for FIKI?) are immune to this asymmetric icing phenomenon?  What about quad-turboprop planes such as the A400M, with its Down Between Engines configuration?


texts: Would jet fuel for an F-16 or F-35 be producible during WW2?

texts:
I understand that different types of engines use different types of fuel, and as the description of the [jet] tag says, turboprops and jet engines use different types of fuel.

So if – like in the works of fiction The Final Countdown and 1632 – modern aircraft did find themselves in 1940, which aircraft would you readily be able to find fuel for? And which would you have to (re)develop the fuel for?

Let's take the following aircraft as examples:

AH-64 Apache gunship
Airbus EC 135 P2e
AgustaWestland AW101
Boeing 747 (whatever variant is most prolific today)
Lockheed C-130 Hercules
General Dynamics F-16 Fighting Falcon
Lockheed Martin F-35 Lightning II
Bombardier Dash 8

My assumption is that even the turboprops will not be able to use the aviation fuel available.

Which aircraft could have been fuelled "locally" first? And will any fly with 1940 aviation fuel, maybe with an additive?


texts: Why do the in house Boeing 737 max tails have a drag chute?

texts:
In the recent videos of some in-house (tagged as Boeing instead of some airline), at the top of the aircraft's tail, there is a rope with a small drag chute attached to it. What is the purpose of this?

The drag chute setup can be seen at 0:15 and 0:30 into this video:


texts: How can the 777X's longer wing reduce vortices?

texts:
I saw the following on this web page:

  The purpose of the longer wing is to reduce drag caused by vortices, or wake turbulence, that form at an aircraft's wing tips. The less drag, the greater the fuel efficiency, and the more cheaply the aircraft can be operated.

How is this correct? How can a longer wing reduce vortices?


texts: What aerodynamic data (drag/lift curves) exists for the L-159 Alca?

texts:
This is one of 3 question in "series" - one question split up in 3 to better reward those responding about each aircraft. Other questions: A-10 Yak-131

L-159 Alca is one 3 planes that are used in the ArmA 3 combat sumilator, but its aerodynamics modelling currently lacks significantly. I'm planning on writing a short "essay" to developers regarding what and how can be specifically fixed in the flight model, but I'd like to back my research with some hard data. Specifically, I'm interested in any of the following:

L/AoA
D/AoA
Side lift/SA (Slide angle)
Max G/velocity
Flight envelopes (like one below for F-15):

Torques can well be left out - it's not a full fledged simulator, but the above data can give quite a good estimation of high level characteristics already

Are there any good sources on any of the above data? Low-mach data is good enough for me.

I understand this is a tall order, but, well, SE is for expert answers - maybe a wonder happens and someone here has it? :)


texts: I'm wandering if I can fly my Phantom 4 Pro in Paris. What are the restrictions? If it's not allowed, can I get an official authorization as I'm an experienced drone operator?


texts: Do some helicopters require classes, type ratings, or special endorsements, the way some airplanes do?

texts:
I've been looking online for the different ratings and classes of helicopters but I can't find much.

For example in fixed wing aircraft you have retractable gear, constant speed propeller, IFR, multi-engine, tricycle gear, etc.

I am curious to know what the helicopter equivalents are. What does a basic helicopter rating allow you to fly? What comes after that?


texts:
In chat, falstro mentioned the "UK IMC rating" and described it as "a lighter version of an instrument rating, allows enroute IFR, but no approaches or departures" (although to be fair he also said that he isn't familiar with the exact definition).

The name "IMC rating" implies that it allows flight in IMC, not just filing IFR in VMC for procedural reasons. But if so, and if approaches are not included, then it seems like it would allow a pilot to fly into IMC with no safe way out again if an emergency required an instrument approach.

So what exactly is a UK IMC rating, what does it not allow that a full instrument rating does, and what is the advantage of having it?


texts: What is this partially disassembled aircraft in the desert?

texts:
I found this plane on Google Earth. I'm guessing it is being deconstructed, as there are no factories nearby. What countries could it have originated from?

The coordinates are 35°54'10.9"N, 117°43'51.6"W. Here's the location on Google Maps.

The plane is about 41 feet long, and seems to have had a wingspan of about 30 feet.

Also, if it is possible, what kinds of planes could this be?

Sorry if this question is not really possible to answer. I'm a complete beginner at aircraft.


texts: Is there any FAR defining an "introductory" or "familiarization" flight?

texts: I have given a number of young people their first inspirational flight. I am a CFI, but I do not issue any endorsement for these flights, and do not charge for my time or the aircraft. Is there any FAR defining "introductory" or "familiarization" flight, or addressing how many times a non-flight-student (no student pilot medical certificate and no student pilot log book) can receive an introductory or familiarization flight?


texts: Is it possible for a pressure loss in the cockpit to not extend to the cabin?

texts:
I have done research into the question of pressure differences between the cabin and cockpit and the theoretical answer I receive the most is that the pressure difference would equalize almost instantly, as cockpit doors are not capable of an airtight seal — and it makes sense, but I recently came across an incident that happened a couple years ago: Sichuan Flight 8633.
On that flight, the windshield actually exploded, and based on the passenger recordings, the cabin seemed a little messy from objects flying around, but they could still hold onto their phones and the flight attendants were able to stand up.
The only comment I could find on that matter had to do with insulation and sealing that protected the passengers from the low temperature and pressure loss. So with that information in mind, is it possible for a cockpit to experience extreme loss of pressure while the cabin suffers minor loss of pressure as on Flight 8633 (an A319)?


texts:
MIL-PRF-5606J, What does "J" means? Does it equal to MIL-PRF-5606?
Please let me know it they are same specification or not.


texts: How to identify shock waves and expansion waves on a representation of the mach number?

texts:
This image is a representation of the Mach number for $M_{\infty}=2.0$
I am very new to CFD and high speed aerodynamics. I'm trying to analyse this image, specifically to understand why the velocity decreases behind the trailing edge.
On the following image, I've tried to identify shock waves (1 and 3) and expansion waves (2) when the direction of the flow changes. However, after an expansion wave, the velocity should increase and it is not the case here so my interpretation must be false. How?

Thank you


texts: What authorization do I need to fly a rebuilt aircraft that doesn't have an airworthiness certificate yet?

texts:
Let's say I rebuild an aircraft in the USA and it does not have a current airworthiness certificate. The DAR requests a check flight during the process of issuing the new airworthiness certificate.

My question is: do I need a check flight authorization or permit from the FSDO to be able to fly without an airworthiness certificate?


texts: What happens if I don't remove the "remove before flight" pad before flight?

texts:
Having just been to a bunch of air museums, I've seen quite a few of these:

 img credit http://www.thewire.com/global/2013/02/iran-new-stealth-fighter-jet-fake/61781/

Those red pads they put in the jet engines that say "remove before flight" - what happens if I try to start the engine with that pad in there? Would the exhaust just blow it out?


texts: Acceleration of a supersonic aircraft after breaking the sound barrier

texts:
People on the physics stackexchange recommended I ask here, so I am pasting my question regarding supersonic aircraft.

I stumbled upon an interesting plot; in particular, the dependence of wave drag on the Mach number:

It is curious to see that the drag coefficient drops so abruptly in the supersonic regime, but I am even more curious if the total drag force acting on the airplane also drops, i.e. if the plane starts accelerating in the supersonic regime.

I did some quick analysis of the problem. The drag force is defined as
$$F_{\text{drag}} = C(v) v^2 ,$$
where $C(v) = A C_D(v) \rho(v)/2$ is the newly introduced drag constant with the drag coefficient $C_D(v)$, flight medium density $\rho(v)$, and cross-sectional area $A$.

Assuming these relations, one can taylor expand the equation for the drag force to find that

$$\Delta F_{\text{drag}} = C'(v)v^2 \Delta v + 2Cv \Delta v.$$

As $C'(v)$ is clearly negative in the supersonic regime, this means that the total drag force drops if
$$C'(v) < -\frac{2C(v)}{v}.$$

It seems that this criterion could indeed be satisfied in air, as the right hand term in the inequality is a fairly small number.

Is there anyone that could elaborate further on what actually happens to the drag force as the plane breaks the sound barrier? Do the plane engines lower their power in order to maintain reasonable supersonic cruising speed, and if they didn't, would they be under too much heat load?


texts: What is the call sign for the US president's private helicopter?

texts: The Air Force VC-25's are Air Force One, Marine aircraft are Marine 1, a private jet is Executive 1. What about when the president is using one a private helicopter?


texts: What are the pros and cons of vacuum and pressure gyros?

texts:
Inspired by this question, I would like to know what the pro's and con's of the mostly used vacuum-gyro and the less used high-pressure-gyro is.

Side-question: Are there any other ways to make the Artificial Horizon work?


texts: What is the make and model of this plane?

texts: I came across this picture taken in the late 1920s. Could you please help identify the make and model of this plane. Thanks.


texts: Does the ICAO definition of an "aircraft" include a minimum altitude capability?

texts:
The German air law includes in their legal definition of a "Luftfahrzeug", which is the equivalent of an aircraft, other devices intended to operate in the airspace if they are capable of being operated more than 30 meters (100 ft) above ground or sea level.

Does an equivalent to this 100 ft threshold exist in ICAO documents or other international regulations? If yes, where?

The background of my question is: if an unmanned aircraft has a technical feature preventing it from flying above 100 ft, would it still qualify as an aircraft and would all regulations about aircraft apply?

I would also like to know, why the 100 ft threshold was put into the German (or other) laws. I could image that it was intended to exclude wing in ground effect crafts from the aircraft category. Is a wing in ground effect craft an aircraft according to ICAO definition?


texts: Which of these is true for a glider flying with constant angle of attack?

texts:
I'm trying to answer the following question, but I'm not sure of which one is correct.

A glider is gliding with constant angle of attack along its path. We can assume the hypothesis of small angles. Under these conditions, the following has to be fulfilled:
a) None of the other answers is correct.
b) $C_L=C_{Lopt}$
c) $\hat{D} =$ constant
d) $\alpha=\alpha_{max}$
e) V must remain constant

Note: D with hat means dimensionless drag.
I've been trying to discard some of them but I'm still doubting about if the correct answer is (a) or (e). Can you help me guess which one is the right one?


texts: Can an airport without an FAA controlled tower have their own tower and controllers?

texts:
Can an airport not eligible for an FAA tower and controllers choose to fund their own air traffic control tower? Can that airport require pilots to taxi, approach, land, and take off according to their tower's instructions?

If so, are there requirements for the controllers in terms of certification, or can they hire anyone they deem suitable for their airport? Do they have to coordinate with the FAA or air traffic control system in some special way?


texts: Has a "fight" ever happened in the cockpit?

texts:
Somehow, a variation of How do long-haul pilots cope with boredom? .

Has it ever happened that the pilots started some small talk about politics, or football, or favourite rock band, or that one cheated with the other's SO, and the discussion degenerated in some strong arguments, if not a fight? Is there anything in place to prevent that (like, procedures on what you're supposed to talk about during free moments)?


texts: What is the Efficiency of Cessna-150's Propeller?

texts:
From that Cessna-150's data, it used Continental 0-200-A 100 HP (75 kW) at 2,750 RPM and with Fixed Pitch propeller with its diameter=69 inches. If power is delivered maximum to the propeller (through direct shaft), then what is power of the propeller to push (thrust) the airplane?

Engine (100HP) ==> Propeller ==> Thrust (? %)

Additional Data of Cessna-150:
Weight of loaded: 680 kgs.
Weight of Empty: 437 kgs.
Wing loading: 9.4 psf (45.8 kg/m²)
Power loading: 15 lb/hp (6.81 kg/hp)
Maximum Engine Power: 100HP (75kW).
Wing Span: 10.2 m.

more detail about the plane can be seen here: http://www.skytamer.com/Cessna_150C.html


texts: If your plane is out-of-control, why does military training instruct releasing the joystick to neutralize controls?

texts:
I quote from Sunday Night's June 3 2019 episode with Capt Kevin Sullivan. I ask about Capt Sullivan's remark with quotation marks below.

Releasing the joystick is undoubtedly counter-intuitive to me, as I haven't been trained in military aviation! Can someone please expound? Please make this counter-intuitive neutralisation of controls intuitive?

  12:20
  Kevin Sullivan's next move is
  12:23
  completely counter-intuitive. Instead of
  12:26
  pulling back on the control stick, he
  12:29
  lets it go. "I have a choice to make. Do I
  12:33
  hold on to it or do I release it? And my
  12:37
  military training for out-of-control is
  12:40
  to release. Neutralize controls." It works.
  12:45
  The plane is no longer falling from the
  12:48
  sky, but now passengers
  12:51
  are being smashed back down to the floor.


texts:
I missed a test question which asked that if an airplane was spinning to the left which wing was stalled.  The supposed correct answer was that both wings are stalled (I had answered that the left wing only was stalled).  However after looking at the this article on Wikipedia it seems to indicate that only one wing needs to be stalled to spin:

In a normal spin, the wing on the inside of the turn stalls while the outside wing remains flying. It is possible for both wings to stall, but the angle of attack of each wing, and consequently its lift and drag, are different. Either situation causes the aircraft to autorotate toward the stalled wing due to its higher drag and loss of lift.

So my question is was it fair for me to have missed that test question since according to Wikipedia a spin can occur with only one wing stalled?


texts: Do carrier-borne aircraft pilots count the seconds on the downwind leg of the carrier?

texts: On carrier landing, someone tells me that the pilots need to count several seconds on abeam leg of the landing pattern, in order to land precisely on the flight deck. Is that true? What do we call for this operation?


texts: Can the VNAV Path angle be modified in a Boeing 737 NG?

texts: In the Boeing 737 NG series, can the usual 3 degrees Path angle used for VNAV Descent be modified through the FMC to another angle?


texts: How can we find maximum lift coefficient of Airfoil?

texts:
I am trying to find the maximum Lift coefficient for airfoil NACA 64A-404. I chose this airfoil for wing. I am stuck at finding the Clmax. I tried to use javafoil but javafoil is showing Cl less than 1 at cruise condition (By putting the Reynolad number value). Although it should be greater than 1?
Is there any other method of finding this out?


texts: Can an airplane fly with on-off control surfaces?

texts:
I understand that, at least for remote-controlled model planes, the control surfaces can point to a range of angles, say, from $-30^\circ$ degrees to $30^\circ$. My questions are:

Would the same airplane work if the control surfaces can only point to, say, $-30^\circ$, $0^\circ$, $30^\circ$.
If I rapidly switch the surface on ($0^\circ$) and off ($30^\circ$) like in pulse-width modulation (PWM). Is that equivalent to having the control surface pointing at $15^\circ$?


texts: What maintenance actions are required after a bird strike?

texts: Does the SRM or AMM detail what Inspections to do following a bird strike? Do the engineers have to examine the bird remains too and report it to someone?


texts: At what age may a student log time and use that time to obtain a rating?

texts:
A few years back the FAA was upset about young pilots attempting to set records and crashing in the process.

Were there any rules instituted regarding logging of time with a CFI / instructor? May a 9 year old or 12 year old log time flown with a CFI and use that time to qualify for a rating?


texts: What are the operational differences between an airplane equipped with a constant speed propeller and one with a fixed pitch propeller?

texts: What makes a constant speed prop different from a fixed pitch prop, and what are the operational differences between airplanes with the two?


texts: What dictates the prop RPM used during cruise?

texts: I've seen on numerous different constant-speed propeller aircraft and different pilots using different RPMs during the cruise phase on a propeller aircraft. What dictates the RPM used during normal cruise operations, and why is that the case? Often there are multiple possible throttle/RPM combinations that deliver the same power, so where would you pick one or the other?


texts: Where can I download AUP/UUP in AIXM format from FAA?

texts:
I am studying about Airspace Use Plan/Updated Use Plan (AUP/UUP).
A defined by wikipedia:

  The Airspace Use Plan (or AUP) is defined as "an Airspace Management
  (ASM) message of NOTAM status notifying the daily decision of an
  Airspace Management Cell (AMC) on the temporary allocation of the
  airspace within its jurisdiction for a specific time period, by means
  of a standard message format."

  AUPs are issued at least on a daily
  basis. An AUP can be updated or superseded through an Updated Airspace
  Use Plan (UUP).2

My goal is to download the AUP/UUP provided by the FAA in the AIXM (Aeronautical Information Exchange Model) or any other machine-readable format.

Do you know where I could get such information?
Do you know who should I get in contact with in order to have access to it?

AUP/UUP Requirements:

Machine readable format (ex: AIMX)
Up to date data
Files must come from FAA website/portals


texts:
What does "best L/D" mean? Is it meaningless without context? Do you need to know "best for what?"

Or, is it synonymous with max L/D?


texts: Any ideas on what caused my engine failure?

texts:
On my second solo flight I came back to do a few landings, and after the first landing I applied full power for takeoff to which the engine responded by just shutting off on me. Not sure if my mixture was too lean, if I applied power too quickly (which I read can temporarily lean mixture too much to keep the engine running), or something else. My CFI wasn't sure what caused this either.
After an embarrassing talk with ATC I was able to get it started up again just fine, and the plane has ran well ever since, so I'm 99% sure I caused the incident. Just not sure exactly what.
I fly a 1976 Cessna 150M. Airport elevation is 5500 above sea level (hence why I leaned my mixture in the first place, as it's advised in the POH). Weather that day was around 0C but very arid.


texts: What is the formula to calculate TAS from IAS

texts: I have seen in flight simulators, that the Indicated Air Speed (I.e. IAS) isn't the same as the True Air Speed (I.e. TAS) Is there a formula coded into the aircraft to calculate this?


texts: How does the thickness of a wing affect its aspect ratio?

texts: As far as I understand, the aspect ratio equals the wingspan divided by the chord or the square of the wingspan divided by the wing area. Given this formula factoring in only the wingspan, the chord, and the wing area, how does the thickness of a wing increase or decrease a wing's aspect ratio? If possible, please explain in plain English without using too complex mathematical formulas.


texts:
I have another AuRo question for you.
When a Helicopter autorotates (ideally) it is in the turbulent wake state and there is virtually no flow through the rotor disk (figure of Leishman attached). Now, when Vc (descent speed) is roughly -1.8 times vh (induced velocity at hover) the vehicle is considered to autorotate ideally.
What if we do not autorotate ideally? Does the vehicle still have to be in turbulent wake state?
The real question: Is autorotation (and thereby maintaining of an ideal rotor rotation speed) possible in the windmill break state?
For instance, in the work of Dalamagkidis the OHA58 (Chapter 5.1.1) and the Raptor30v2 (Chapter 5.3.1) do not seem to be in turbulent wake state.
As for my calculations, vc/vh was always slightly lower than -2.
However, the vehicles seem to perform well and land softly.
So is the windmill break state a legitimate state for "autorotation"?
Thanks for helping me out! :)


texts:
Do two stroke engines for small aircraft suffer from degradation between overhauls?

For an automotive engines you can usually expect it to retain most of it's power between services for a long time until a specific failure occurs. During the time between overhauls on a small two stroke aircraft engine like a microlight, does the power available drop noticeably over time and increase after an overhaul/rebuild? Seeing as these only have a small power available to them to the begin with, as in 20-60hp, and this is in turn reduced with altitude, you would have to adjust your flight planning to compensate.

The other option is to have the TBO set to make sure things are changed before power loss becomes an issue, but this would necessarily involve changing out components while they still have usable life in them.


texts: Could the crew of XL Airways Germany Flight 888T not hear important chimes, due to the stall warning?

texts:
I am intensively researching on XL Airways Germany Flight 888T at the moment.

I wrote and researched hours and hours. Now I would like to know something about the ECAM and the Airbus Stall warning:

The crew of 888T started a stall test with faulty AoA-Sensors. They wanted to test the stall protection system. At a point, the Airbus stall warning was played. A few seconds later, the control laws degraded to Direct Law. The crew missed this degradation and I just want to find out why.

I found out, a control law degradation is a level 2 ECAM warning. That means a single chime will be played. Can someone confirm this?

I also heard, the stall warning suppresses all other sounds, because a stall has priority over all other things. But I don't know if this also applies for the ECAM Sounds. Does anybody know if a stall warning really suppresses every sound?


texts: What about hours flown solo without a student pilot certificate?

texts:
My instructor has ruined my training. 2.5 months ago when I started private pilot training (FAR61) I had zero knowledge about aviation.  After 1.5 months he signed me off for solo and I finished all the requirements and we sat together to register through IACRA for my checkride, and guess what? He had forgotten to tell me I needed a student pilot certificate before I go soloing.

Besides the risk he made on my life ( imagine I crashed during solo and insurance definitely would deny any claims since I was not legally allowed to fly! ) and that I will be grounded for weeks until I get student pilot certificate, I don’t know what will happen to those solo hours ?

Do I have to re-do the whole solo requirements or they will still count towards my hours?
Do I need to file a complaint through AOPA or FAA or contact my AOPA representative?
What are the rules and who is responsible for that?


texts: What causes a plane to lose its roll momentum

texts:
I am currently developing a flight simulator but there is one force I can't figure out how to simulate using real world physics. When the pilot pushes the stick to the right, the plane will reach a roll rate that it will keep; and when the stick comes back to its neutral position, the plane will stop rolling, more or less quickly.

Is there a formula, or an approximation that explains how the plane will stop its roll? On what does it depend? Apart from wing area, does airspeed and lift impact this? Or does it depends on angular velocity?

I need a formula that I can compute to slow my roll down.


texts: What is the throttle setting of a piston aircraft during cruise?

texts:
I am learning to fly nowadays, I am sorry if this sounds like a dump question.

What is the throttle setting of an aircraft during cruise flight?

After stabilizing the flight after climb do i need to turn down the throttle?


texts: Why would the cabin crew spray the cabin before landing?

texts: Once when I was on a plane that was about to land, the cabin crew came around and they were spraying these small canisters. I've been on many flights but it was that particular flight where they did the spray. Can someone please tell me what those spray's are?


texts: If the number of flights in the world exceed 2^24 how will ICAO allocate the address to the flights?

texts:
What is the approximate number of commercial flights in the world as of now?
If the number of flights do exceed will they use the concept of frequency reuse in cell phones(dynamic allocation of addresses)?


texts: What can cause a watchdog failure in an INDRA MSSR?

texts:
I am responsible for Mono-pulse Secondary Surveillance Radar (MSSR) system that resets itself after a watchdog failure.
So far I have found the following:

An unwanted number of replies are received by it.
A noise test was also done but the test didn't find any interference,
The system is running smoothly, but suddenly from west direction an excess number of replies are received which cause my MSSR to reset.
this interference time is only occasionally, it come out whenever they wanted,
The Frequency Allocation Board team has been contacted to find out the source of this interference,  but since it happens only occasionally they are also unable to find it.

If someone has experience on it or face the same issue kindly reply as soon as possible.


texts: Does a flight dispatcher need to update the flight plan during GTB and ATB?

texts: Does a flight dispatcher need to recalculate and resubmit the flight plan to the pilot during ground turn back (GTB) and air turn back (ATB) scenarios?


texts: Are there any rules regarding construction near a private strip, such as stand off distance?

texts: I would like to construct a facility next to a private strip.  What are the FAA rules concerning this such as stand off or height?


texts: Why does Logan Airport's Runway 32/14 only have arrivals on the 32 heading?

texts: I was going through this PDF document on Logan International Airport's runway usage and I saw that Runway 32/14 only has arrival activity. Why is that the case? Is this the the reason or part of it why there are only stripe marks on the side of the runway close to "32"?


texts: Why does the TAF provide forecasts at irregular intervals?

texts:
A TAF is published 4 times a day at 6 hour intervals. However if you look at the forecasts within a TAF one might be at a 4 hour interval and the next at an 8. Just look at this example:

TAF KPDK 071124Z 0712/0812 32009KT P6SM SKC
FM071600 33011G18KT P6SM FEW045
FM080000 32008KT P6SM SKC

Why not publish at consistent intervals?


texts: How can I find out the reason for an aborted takeoff?

texts:
I was listening to ATC at LAX today and heard them cancel AA 253's takeoff clearance and instruct them to abort their takeoff; it sounds like they were already rolling down the runway when it happened. The call to stop was pretty insistent.

In a lot of hours of listening, I don't remember hearing that happen before, I'm really curious why they did it. Is there any good way to find out?


texts: What are the most powerful airplanes that ever flew?

texts:
This question What are the least powerful airplanes that ever flew? made me wonder what the most powerful manned airplanes are that ever flew. There are two sensible categories, I suppose:

Most thrust overall.
Best thrust-to-weight ratio.

EDIT in response to a comment by @ratchet freak:

Answers including rocket-powered aircraft are welcome, although I'm also interested in other propulsion systems. However, I'd like to exclude rockets by requiring the craft in question to be able to at least land on, if not start from a runway.

EDIT 2 in response to a comment by @Robin Bennett:

I'd like to restrict this to reusable craft, in the sense that they should be fine to go again with not much more than a refuel. So I guess that excludes the Space Shuttle.


texts: Are the "centerbody", "fan hub frame", and "intermediate case" all the same thing or separate parts?

texts:
I'm curious about the frames & cases at the front of an engine. I've seen OEMs call them the centerbody, fan hub frame, and intermediate case. Are these all the same thing or are these each a separate part? It seems that each OEM has their own vocab.

The fan case is the one I can figure out. I'm more talking about the area right behind it before the HPC


texts:
Out of curiosity (I am not a pilot, but do enjoy watching this aviation forum).

Question: What are the continued education requirements for commercial / airline pilots?

Per FAA rules (if that exists)
If you are a commercial pilot, do you spend more time than mandated learning?
What percentage would you estimate is spent in simulators vs textbook / classroom (if applicable)?


texts: Is a 61.31 solo endorsement a one-time thing, or does it need to be repeated?

texts:
The FAR 61.31(d)(2) reads that a person can act as pilot in command if they:

  Have received training required by this part that is appropriate to
  the pilot certification level, aircraft category, class, and type
  rating (if a class or type rating is required) for the aircraft to be
  flown, and have received an endorsement for solo flight in that
  aircraft from an authorized instructor.

Is this endorsement a one-time thing, or does it need to be "renewed"? I met an glider instructor who claimed that my glider solo endorsement is no longer valid because my power license lapsed.


texts: Is the Boeing 777X being certified as a derivative of the 777 Classic?

texts:
Given the corner cutting Boeing did with the Max certification, is the FAA allowing the 777X to be certified as a derivative (easier) of the 777 Classic or requiring a new Type Certificate? (harder)

The wings are new, the engines are new, the flight deck is new (from the 787 I understand), the weight is higher and the fuselage longer.


texts: Can you own a fractional portion of a kitplane or experimental airplane?

texts: I understand that experimental/kit planes can't be used for 'training for hire', i.e. an option of leasing them to flight schools is out. But... is it possible to own such aircraft on the fractional basis? Is there anything in regulations that would prevent me from holding, let's say, a 1/4 ownership of a Sling 4?


texts: Is collaring a circuit breaker considered deactivation by the FAA?

texts:
Let's say you discover that your landing light is inoperable during the preflight. Your aircraft doesn't have a MEL, so you follow 14 CFR §91.213(d). Assuming you do everything else required (placard, etc.), would placing a collar around a circuit breaker be considered deactivation?

If not, is there anything that a private pilot can do that would be considered deactivation?


texts: How to correctly interpret the taxi procedures in ICAO Doc 4444?

texts:
I have a question to ICAO Doc4444, Chapter 12.3.4.7, Taxi procedures for departure, c).

My question is how to interpret the following, knowing that words in parentheses are mandatory, and words in square parentheses indicate optional additional words.

  TAXI TO HOLDING POINT [number] [RUNWAY (number)]
  [HOLD SHORT OF RUNWAY (number) (or CROSS
  RUNWAY (number))] [TIME (time)];

I assume that this can be exploded to 12 variants (not including TIME at the end of each variant which would give another 12 variants).

TAXI TO HOLDING POINT
TAXI TO HOLDING POINT A1
TAXI TO HOLDING POINT A1 RUNWAY 09
TAXI TO HOLDING POINT RUNWAY 09
TAXI TO HOLDING POINT HOLD SHORT OF RUNWAY 30
TAXI TO HOLDING POINT CROSS RUNWAY 30
TAXI TO HOLDING POINT A1 HOLD SHORT OF RUNWAY 30
TAXI TO HOLDING POINT A1 CROSS RUNWAY 30
TAXI TO HOLDING POINT RUNWAY 09 HOLD SHORT OF RUNWAY 30
TAXI TO HOLDING POINT RUNWAY 09 CROSS RUNWAY 30
TAXI TO HOLDING POINT A1 RUNWAY 09 HOLD SHORT OF RUNWAY 30
TAXI TO HOLDING POINT A1 RUNWAY 09 CROSS RUNWAY 30

My questions are:

Is my number of variants correct?
All variant are instructions to taxi to a holding point, in case 1, holding point is obvious to the pilot due to runway in use? Correct?
In all cases, the instruction gives clearance to taxi to a holding point without follow up by any other clearances, but for
case 5, 7, 9, 11 the pilot must wait at holding point short of runway 30 (for stopbar light etc. to be opened). Correct?


texts: What does gravity compensation do in flight control?

texts: In flight control designs for lateral directional movement, there is a block named "gravity compensation". This block changes yaw rate measurement from "$r$" to "$r-g/Vcos(\theta)sin(\phi)$" before it is sent to the controller. How does this block change the equation of motion?


texts: Why aren't there any widebody propliners for the high-density short-haul markets?

texts:
Jetliners come in both narrowbody (one aisle) and widebody (two or more aisles) versions, but all propliners, to the best of my knowledge, are narrowbody aircraft.

Now, granted, one of the big reasons for having widebody airliners is to have an aircraft big enough to cross continents and/or oceans with a profitable passenger load, and trans[continental/oceanic] routes are (at least in civil aviation) exclusively the province of jets, because speed.

However, in places with lots and lots of huge, densely-populated cities packed fairly closely together, such as much of East Asia, passenger numbers are so high as to require the use of large widebodies even on very short-haul routes - and, on short-haul flights, propliners hold a considerable advantage over jets (jets are horribly inefficient in the dense air at low altitudes, and short-haul flights aren't long enough for an airplane to have time to climb to long-haul cruising altitudes, whereas propeller aircraft, with their lower speeds, and, thus, lower drag, do just fine going low, and short-haul flights are short enough that slower aircraft aren't a major disadvantage; this is why, even though propliners are essentially extinct in long-haul airliner service, they continue to take a large chunk of the short-haul market).  A widebody propliner would be perfectly-suited for these sorts of jam-packed short-haul markets.

So why aren't there any?