texts: What are the risks involved when doing a classic zero-g maneuver?

texts:
I suspect most pilots have done it at least once: briefly experience zero g when flying a parabolic path. It's quite an experience (if your stomach can handle it).

Question is: are there any risks involved in doing something like that? (I know, getting in an airplane by itself is a risk, but that's not the point)

I could think of a few potential risks, but I'm not sure if they are real or not:

Engine lubrication in single engine piston airplanes

And if not properly executed:

Risk of a stall, both in the pull up phase and in the "arc" phase
Overstressing the airplane when pulling out of the dive to get up to speed

Follow-up questions: Is it considered to be an acrobatic maneuver? Are there any regulations that would prohibit it?


texts: What is the meaning of “American 755, turn right, heading 320"?

texts:
I am studying a text entitled Unmanned Aircraft Systems. How can we simplify the instruction in quotes so that it is more understandable and can be understood by a nontechnical. Please note I am not seeking to know all technical jargon of routing aircraft, rather to get what a pilot is told with this instruction to do.

  Ideally, the communication process includes three parts: the
  initial call, readback, and hearback. For example, an ATCO would issue an instruction “American 755, turn right, heading 320.” Pilots onboard the aircraft would respond, or readback the message “Right, heading 320, American 755.”


texts: What is the name and purpose of this part on the flap at the DA40?

texts:
There is a part on DA40's and also DA42's flap. I cannot find the technical document and I couldn't decide what is the purpose of that part. Is it a mass balance part or what? You may see the part at picture. (Note: First picture is not showing the part I meant to ask. The picture was wrong but I keep the picture not to make comments meaningless about it. Correct part is marked at second picture.)

Edit:

Sorry everybody, I drew wrong part before by mistake. The part marked at first picture is the aileron control rod. All previous answers and comments are correct for aileron. I add a new picture for the correct part and I found out it functions as a mass balance horn. We see housings from pictures but the related part is inside the housing.
Edit time: 11th Nov, 2016 10:30 UTC


texts: Can anyone identify this 1970s Mitsubishi pushback tug?

texts:
What's the original name and specifications of this probably 1970s pushback?  The bottom of this model is stamped "Mitsubishi towing tractor." Made by Tomica. Bought at a flea market in Kyoto circa 2010. Googling finds only the toy.
I'm particularly interested in what looks like an elevating cab, possibly at both ends.
Details from comments so far:  This model is 1:119 scale.  The pushback was in use at Tokyo's Haneda airport at least through 1976-78.  It's not a Hough T-500 Paymover.
Photos of other pushbacks show that this one is unusual in having four separate cabs, and wheel arches that are perfectly semicircular.

Sept. 2020 edit before the bounty expires:
The toy is from a box labeled
ジャンボエアポートセット ミニカー
which translates as Jumbo Airport Set Minicar.  The UPC code is 4904810 26441 5 (or 8 instead of 5).
These sets are sold at the Japanese
ebay.
Can a Japanese speaker glean any clues from the back of the box?  (I can guess at the kana, but not the kanji.)


texts: Where is the best centre of gravity for planes like the Berkut 360?

texts: I am making an RC plane similar to the Berkut 360. Can anyone please suggest where is the best location for the centre of gravity for such a plane? (With explanation please)


texts: How do barometric altimetry systems compensate for nonstandard pressure lapse rates?

texts:
Barometric altimetry relies on atmospheric pressure dropping at a steady rate with altitude, starting from a measured ground-level pressure.  This, in turn, relies on atmospheric density dropping at a constant, steady rate with altitude, which it does not always do:

For instance, if the air close to the ground is much more humid (and, thus, less dense) than the air higher up, then the atmospheric density will drop at a slower-than-standard rate with altitude as the increasing rarefaction of the air is partially compensated by its decreasing humidity, causing the atmospheric pressure to fall off more slowly with altitude than it “should”, and causing an uncorrected altimeter to read falsely low.
Conversely, in a industrial area, with heavily-polluted low-level air containing high concentrations of dense gasses such as carbon dioxide, sulfur oxides, nitrogen dioxide, hydrogen chloride, sulfuric and nitric acids, and heavy hydrocarbons, plus lots of soot and tar particulates which raise the air’s mass significantly while adding very little additional volume, atmospheric density falls off faster with altitude than in a standard atmosphere, as one rises out of the pollution-densified lower layers; this causes the atmospheric pressure to lapse at a higher-than-standard rate, which would cause an uncorrected altimeter to read falsely high.

How do barometric altimeters compensate for nonstandard pressure lapse rates resulting from nonstandard atmospheric density profiles stemming from variations in atmospheric composition with altitude?

This is different from How does an altimeter deal with the non-linear pressure gradient?.  That question is about how an altimeter is designed to match the non-linear ISA model; my question is about how one deals with situations where the ambient air isn't the ISA.


texts: What exactly does it mean, that plane has diverted due to the needs of a passenger?

texts:
Twitter account for Flightradar24 has reported twice in past 24 hours about two different British Airways flights that has diverted their original route "due to the needs of a passenger" (here and here).

What exactly does it mean? Is it:

a passenger requesting to land on other airport, because he forgot his wallet?
operational decision to put more passengers on-board empty plane?
something else?


texts: How are procedures for curved-runway operations different from those for straight runways?

texts:
Runways having a significant curve between the two ends aren't exactly common, but they do exist, one good example being Elk City Airport's runway 14/35.

When operating to or from an airport with a curved runway, what does one have to do differently than with a straight runway?


texts: Will this simple equation (pic attached) produce a rough estimate of the top speed of a prop driven aircraft?

texts:
Calculating the approximate top speed of a vehicle is straightforward.

$v = \sqrt[3]{\frac{2P}{c \cdot D \cdot A}}$

where

v = velocity of the vehicle
P = power of the engine
c = coefficient of friction
D = density of the air
A = the area of the front of the vehicle

Using this equation you can get a rough idea of the top speed of a car if you know its engine power, the body’s coefficient of friction and the area of its front profile.

Is it possible to use this same equation to determine an approximate top speed for subsonic aircraft?  No doubt engineers at Boeing have to account for 100 additional variables, but is it good enough to produce a decent approximation for props that fly less than 500mph?

Also does the picture I attached below show the correct way to account for variables $A$ and $c$?

If $c$ represents the friction along the entire surface of the aircraft does this suggest that all things being equal an aircraft with twice the surface area would have twice the coefficient of friction?  Or am I looking at $c$ incorrectly?


texts: Besides size, what determines the cost of creating a composite structure for a single engine piston aircraft?

texts: When designing an aircraft (LSA or GA), how would one minimize the cost of construction when the aircraft is composite. To be clear, I am talking only about the structural components, not the interior, engine, or instruments.


texts:
I know that some manufacturers both sell kit and finished version of their aircraft. For a fair comparison of accident rates, i was wondering:

What are the accident rates for kit built aircraft vs. normal aircraft of the same model?

Are the home-builds less safe than the company finished aircraft?


texts: How does the target indicator on a jet fighter work?

texts: How does the target indicator in Jet Fighter Aircraft work?  How does it stay on target? Is this queued from the radar, from infrared or is this image classification? What does the x in the target indicator mean? Are the other symbols around it part of the target indicator or related to something else?


texts: What are these parts on the wing of a Boeing 737?

texts:
In the picture above:

What are the parts numbered "1" and and "3"?
Is "2" maybe the reinforcement of the pylon?


texts:
Cirrus clouds:

Are they warmer than the environment? - Cumuliform.
Or are they cooler? - Stratiform

What differences do cirrus clouds have to the "Cirro" versions of a cumulus or stratus?


texts: How do messages get from the destination airport to a pilot?

texts:
A captain waiting in her airliner for take-off at an airport might inform her passengers:

  We'll be waiting another ten minutes before we're able to take off, as traffic is very busy at [destination], and we have to arrive in accordance with the landing slot we've been given.

How did that information reach the pilot, and what route did it take?

The answer I am looking for might be something like: the slot controller allocates the slot in the local slot control system database. This is communicated via a dedicated digital radio satellite system to ATC at the departure airport. ATC informs the local despatch controller by telephone or short-range radio. Finally, a runner is handed a slip of paper with the details and personally puts it into the pilot's hands.


texts: How does an engine work when an airplane has $v=0$ on the ground?

texts:
I mean, for a turbofan:
$$ T= \dot m_{air,h} (1+f) v_{e,h}+ \dot m_{air,c} v_{e,c}- (\dot m_{air,h}+ \dot m_{air,c} ) v_0+ (P_{e,h}-P_{amb} ) A_{e,h}+ (P_{e,c}-P_{amb} ) A_{e,c} $$

but
$$ \dot m_{air}=\rho Av_0 $$

do I have to impose  $\dot m_{air}$?
in this case how the thrust expression change (in particular the terms with $v_0$)?


texts: According to ICAO, which rules are applicable to SBAS Non-Precision Approach Procedures?

texts:
I am studying the Satellite Based Augmentation System (SBAS) from PANS OPS manual 8168, Volume II, sixth edition, and I have a problem concerning the criteria of SBAS-NPA.
In Part III, Section 3, Chapter 5 called "SBAS NON-PRECISION APPROACH, APPROACH
WITH VERTICAL GUIDANCE AND PRECISION APPROACH
CAT I PROCEDURES", it states:

5.1.1 Procedure construction This chapter describes the SBAS criteria for the NPA, APV 1 and PA CAT I procedure segment, which are specific to
the performance of SBAS systems. Throughout this Chapter SBAS OAS refers to both SBAS APV OAS and SBAS
CAT I OAS. The APV or CAT I segment includes the final approach, and the initial and the intermediate phases of the
missed approach segment. The other phases of flight are generic in character and are presented in Part III, Section 3,
Chapter 1 and Chapter 2.

However, a few chapters before and, specifically, in Chapter 3 called "NON-PRECISION APPROACH PROCEDURES", it describes the rules concerning the Non-Precision approaches in general.

3.1.1.1 This chapter describes the non-precision approach criteria for RNP APCH procedures.

The problem is that it's not clear to me which criteria to follow. Do the rules of the general Non-Precision approaches also apply to SBAS Non-Precision procedures, or the latter follows its own distinct rules covered solely in Chapter 5?
Another issue that troubles me is that the topics discussed in this manual are scattered through its sections, without any easy way to track the desired information. For example, in Volume I, it states:

1.2.4.2 Straight-in approach. Wherever possible, a straight-in approach will be specified which is aligned with
the runway centre line. The pilot should be aware that for non-precision approaches, a straight-in approach is
considered acceptable if the angle between the final approach track and the runway centre line is 30° or less

On the other hand, in the aformentioned Chapter 5 of Volume II, Part III, where it discusses SBAS, it has a special paragraph discussing the use of SBAS approach with offset alignment.

5.7.1.1 The final approach track shall intersect the runway extended centre line:
a) at an angle not exceeding 5°; and
b) at a point where the nominal glide path reaches a height called intercept height of at least 55 m (180 ft) above
threshold.

This becomes really confusing, since I can not comprehend which rules apply exclusively for SBAS NPA and which rules are supposed to be followed in every case of non-approach procedure.
I would be grateful if someone could help me clear this out and read the manual the way it is intended by their authors.


texts: How often do jet-liners have touch and go landings?

texts: I read that a go around is 1-3 out of every 1000 and I wondered how rare it is for a large commercial plane to actually hit the runway before deciding to go back up again.


texts:
Let's restrict this question to best sellers airliners (A320 and B737). On  this aircrafts, the THS is used for pitch trim. The speed requirements may not be has intense as for elevator as it control a longer term action. I excpect the elevator to act quickly (I imagine less than half a second from full up to full down, several degrees per seconds) but what about the THS? Does this speed change depending on the flight phase? (I see no reason, but I may be mistaken)
This question is restricted to autotrim function (otherwise, I think the speed of pilots hands may be the limiting factor)


texts: Why are cambered airfoils used for horizontal stabilizers in some designs?

texts:
From what I know, usually NACA9/12 or similar symmetrical airfoils are used for the tail.

Still some aircrafts use highly cambered airfoils for elevators.

What are some advantages and disadvantages of this configuration?


texts: How does a plane's weather radar ignore returns from other weather radars?

texts: In busy and congested airplane areas (around large airports, for example), there could be dozens of commercial aircraft, all with their own weather radar transmitters/receivers actively transmitting and receiving radar signals.  How are the radar receivers able to discern between their own radar's returns from those of other aircraft?  I can't imagine them to all have different TX frequencies to prevent interference, but not sure how else the receivers could be set to reject other aircraft's radar transmissions.


texts: Is there an official English version of LTF-UL?

texts: I have found the German version of the ultralight regulations under Germany airworthiness authority, but I have not found a link for English version of that. is there any?


texts: How can I find out if a close encounter in flight would be classed as an airprox?

texts:
I was on a Jet2 flight LS257 which left Leeds Bradford (LBA) at 06.30 on Sunday the 11th of September 2016.

Approximately one hour and ten minutes into the flight we passed very close to a Ryanair jet going in the opposite direction. I know that distances can be deceptive but this was much nearer than any time I have ever seen in the past. I often watch for other planes and have seen them countless times at varying heights and going in all directions but this was extremely close in my opinion.

Is there a way to check how close the two aircraft were?


texts: If the radio fails, can a pilot contact the tower by cell phone?

texts: Is it an accepted practice to notify the tower of a radio failure by cell phone, and use the cell phone as a radio, or are there other ways of dealing with radio failure?


texts: What is the purpose of the second wifi network on board (some?) B787 aircraft?

texts:
I recently flew for the first time on a Boeing 787-8 Dreamliner, registered A7-BCY. This aircraft had the universal symbol for wifi externally displayed beside the entrance door, and as wifi on an aircraft was another first for me I was keen to try it out. Which I did, without much fanfare.

The wifi used to provide internet access was named along the lines of "OneAir", which is consistent with the name of that airline's connectivity/On-board entertainment services.

What intrigued me was that there was a second wifi network available (albeit secured from public access) which was named with the aircraft's registration "A7-BCY" in the SSID of the network.

What is the purpose of this network? What data would you be able to access/see if you were to connect to it using a laptop (for example)?

(Note: I know there have been some questions here and on computer security regarding the vulnerability of modern airliners to hackers - I'm less interested in "doomsday scenarios" with this technology, and more interested on what legitimate uses there are of this network)


texts: What considerations drove the choice of the Solar Impulse engines configuration?

texts:
Solar Impulse makes me think of a motorglider due to its aspect ratio.

The Upward cranked tips wing configuration along with the engines configuration particularly draw my attention:

The 2 innermost engines are almost close to the thrust line
The 2 outermost ones are right where the wing crank.

Question:

Was the engines configuration mainly adopted out of structural optimization sake or do other relevant considerations (such as ease of flight control in case of asymetric engine failure etc.) come into play?


texts: If all fighter jets become stealthy, how will they fight each other in the future? In dogfights?

texts: I came across this question on dogfight-capable fighter jets still being made. If all aircraft become so stealthy, how will they fight each other? Only in dogfights, I presume. Or am I wrong?


texts: Question on sUAS course in lieu of knowledge test for Part 61 certificate holders

texts:
If I am a PPL already, it appears that you can just take a course and pass a quiz to satisfy requirements for part 107 as such:
"If you are a part 61 pilot certificate holder and you have a current flight review (per 14 CFR part 61.56), successful completion of this course is your ONLY training and testing requirement. At the end of this course, complete the online knowledge check (exam) and print your completion certificate."
Now, I received my PPL in August 2019 and my IR on August 2020, and I know that both reset the clock on flight review requirements. However, since they specify flight review in the requirement, do I really need one or do the oral/checkrides for the ratings count as part of that review?


texts: Why is this type of rotor hub so rare...?

texts: I wonder why is this type of helicopter rotor hub so rare... It is a very simple construction, having no flap or lead-lag hinges. A universal, constant-speed joint leaves the rotor free to find his position in space, and the only complication is the swashplate, essential in order to control cyclic and collective pitch. This type of hingeless rotor hub needs little maintenance and is relatively easy to build with standard materials... But it's nevertheless nowhere to be seen...


texts: How do you figure out which frequency to contact approach on for a class bravo transition?

texts:
I'm about 20 hours into my PPL, so maybe I just haven't gotten to this part yet.
Suppose I'm flying KFCM to KRNH and I want to request clearance across the bravo. How do I figure out which approach frequency to contact KMSP on?
From liveatc.net, it looks like approach is 121.2 or 126.5 (for low altitude). At skyvector, 121.2 and 126.5 are listed under Class B. From the Chart Supplements - neither of those frequencies appear. Am I just looking at the wrong information?
I found a similar case for KPBI where the approach frequency (124.6) doesn't show up on the chart supplemental.


texts: Can an IFR clearance be issued and flown through IMC in class G airspace?

texts:
Let's say an IFR flight was planned to depart from a non-towered airport with class G airspace extending from the surface to 700 feet AGL. The flight visibility and ceiling both go down to 0. Can the pilot get an IFR clearance?

If the airport had class E airspace from the surface up it would be in controlled airspace from the ground and I'm positive that an IFR clearance could be issued allowing IFR flight in that class E airspace right from takeoff.

In the case of class G airspace from the ground, the airspace is uncontrolled. Could an IFR clearance be issued that allows IFR flight and waives the basic VFR weather minimums for class G airspace?


texts: What daily commercial flight is the oldest / has been running the longest?

texts:
Out of curiosity, what flight, currently still operating, has the earliest inception?

There are several ways to define this, and I expect available information will determine what definition is most useful. As an example, if a flight's inception date is the earliest date such that there has been a commercial flight on every day (or every week) between that date and today, what flight has the earliest inception date?

Also interested in a flight using the same aerodromes, or with the same airline, or even aircraft type.


texts: Does an airline have to pay if fighters intercept one of its aircraft?

texts:
It sometimes happens that because loss of radio communication or because wrong frequency tuned in during ATC handover etc... a country has to send fighters to intercept an aircraft in its airspace. If such happens, does the airline have to pay a fine (presumably this would/should cover the expenses of the dispatched fighters)? What happens with the pilots who make this mistake?

Let's assume a European country, member of NATO and a commercial flight.

EDIT - 2018-12-17

It looks my country (Hungary) will be the first in the EU which will charge airines (actually based on the Hungarian Official Gazette they can charge anyone not just commercial flights) in this case. The amount itself is not defined, the Aviation Authority will be responsible for determining it (of course along with the military counterparty). Link for the Hungarian Official Gazette - in Hungarian


texts: What do jet pilots say during the takeoff as they are speeding down the runway?

texts: I was watching a documentary on youtube and the pilots always say something that sounds like "B1E" when they have enough speed to take off. What exactly are they saying, and why do they say it?


texts:
A NATS video recommends the use of a listening squawk as one of the means to avoid infringing airspaces.

What is it? And what is the equivalent of it outside of the UK? Say in the US.


texts: What are the requirements to convert an FAA certificate to EASA/JAA?

texts:
If a pilot holding a US certificate wanted to convert it to an equivalent EASA (JAA?) certificate, what training, flight experience, and exams are necessary to obtain equivalency?

Does the process differ for private, instrument, commercial, ATP, and instructor ratings?


texts: What airspeed is required at sea level to create the same aerodynamic pressure as cruise altitude?

texts:
I would like to know what speed would be required, at sea level, to exert the same aerodynamic pressure as experienced at cruise altitude.
For example, if an airliner were traveling at 500kn at 35,000' what speed would you travel at sea level to experience the same forces on the air frame?


texts:
The Comac ARJ21, China's answer to Embraer's regional jets, was launched with great fanfare in 2016.  However, if FlightRadar24 is to be believed, launch customer Chengdu Airlines does not appear to be flying any of its aircraft (click open AJ27, then check the aircraft).

Are any airlines actually flying the Comac ARJ21?  If not, when and why did they stop?


texts: How come planes can endure more positive than negative g's? I.e. how come V-n diagrams are not symmetric?

texts:
In this question A380 reverse thrust on only half the engines some doubts were raised about the strength of structures in certain directions.
Specifically, Peter Kämpf states:

  Aluminium and Carbonfiber are almost as good in compression as in
  tension, so the direction of the load is secondary. This is not true
  if buckling stiffness is not sufficient, but in case of wing in-plane
  bending, buckling is of no concern.

This made me wonder:

How come V-n diagrams are not symmetric?

From the image it can be seen that the structure at 150 knts can only cope with -1.8g, but +3.8g.
Where does this difference come from, is it coming from difference in buckling stifnesses in different directions?


texts: Does a safety wire prevent a fuel filter to detach during flight?

texts:
I know that fuel filters on aircraft engines have some features that avoid the bowl from detachment during flight, and that they can be secured using safety wire as shown below.

I've also heard that installing safety wire is very time consuming. Is that true?
What is your experience with installation & safetying of fuel filter bowls?


texts: How long did it take to set up a portable runway?

texts: How long did it take to set up those metal runways? Were the metal sheets spiked into the ground? How big were they? Also, how are commercial runways built?


texts: Can you log PIC for dual time after you have your PPL?

texts:
I've looked up a few different regulations (FAA) regarding the logging of time in my logbook and am unclear on how to log my time.

Here's the scenario: I am a private pilot and am getting checked out on a new aircraft. I am sitting in the left seat and am legal to operate the aircraft currency/certificate-wise, but a CFI is taking me through the motions with a new plane. How should I log this? Dual, PIC, or both?

Also, here's scenario two: everything is same as in the above scenario except I am getting checked out on a complex aircraft for my complex endorsement. How should I log this?


texts: Why are podded engines preferred over engines fitted inside the fuselage or wing?

texts:
Given the fact that podded engines on the wings of airplanes cause much drag (and thereby contribute to a lot of loss of efficiency), why do airliners still prefer podded turbojet engines over turbojet engines fitted inside the fuselage (or inside the wing) ?
Edit
This question is not regarding "What is the role of Pylons in a podded jet engine", but this is about "Why podded engines in the first place?"


texts: Is there any agency or meeting, at global level, that rules flight zone interdictions?

texts:
Considering the number of conflicts in the world, and the tragic event of the airliner crash over Ukrainia caused by military action, there are a lot of flight interdiction zones on the world.

From the data I gathered, those interdictions are pronounced by regional agencies, such as the FAA for the USA or the ESA for Europe. However, some countries like United Arab Emirates or Qatar have airline companies, but I don't think they have agencies such as the FAA. Still, do airplanes for those companues fly over East Ukraine?

So the question is:

Is there any global agency that coordinates the questions of dangerous flight zones?
Is it able to enforce an interdiction, or does it just put up meetings to coordinate the FAA, ESA and airline companies?


texts: What's the mechanical 'whoosh, whoosh' sound in this video?

texts: Sound in question comes right after the warning sound at 22:57.


texts: What exactly is VMO and how does it affect a plane when it is exceeded?

texts:
I read an article that mentioned "VMO" speeds of a 747 and that the plane, when it exceeds its VMO, shakes uncontrollably and destroys itself.

I've never heard of planes doing this and the article explained VMO in a way that is beyond my understanding.

For someone that doesn't know much about aviation:

What does VMO stand for and how does it affect planes when exceeded? If it does cause the plane to shake to the point that it destroys itself, why is that?


texts: Why is there such a large price difference between the A350 and B787?

texts: What are the reasons for quite significant difference in price between the Airbus A350 and Boeing 787? List prices for the A350-900 and 787-9 are around 317 million USD and 190 million USD respectively.


texts: Is this blended wing body trijet airliner real?

texts: Is it a commercial plane? Is this a better design in any way than regular engines on the wings?


texts: Won't sonic booms prevent Space X's BFR intercity transport plan from being acceptable?

texts: Considering that Space X have just announced that their BFR can take anyone anywhere in the world in under 1 hour, that would be enormous speed, does this rocket not produce sonic boom?  If not is it because of its shape and that it does not have wings? Will it ever be allowed to fly across the US above the oceans and anywhere at those speeds considering again sonic boom?


texts: Is there any way I can check the status of my medical?

texts: I was deferred my third class medical because of a certain condition and the doctor said I’ll hear from the FAA in about 3-4 weeks with either my certificate  or they’ll ask for more information.  It’s been 3 weeks going on 4th week, and I’ve heard of them taking 2 months or longer so I was just wondering is there any way I could check the status of my medical like it can tell me it’s been sent back or is currently being reviewed or etc?


texts: Do low-cost airlines make more profit than luxury airlines?

texts: I was watching this TV show and it said that currently low-cost airlines e.g. Ryanair/Easyjet make more cumulative profits than more expensive long haul airlines such as British Airways and Virgin airlines. This confused me because long-haul flights are more expensive and from looking at the type of aircraft British airways uses, those flights can carry more passengers than a 2 propeller Ryanair flight. So can someone please tell me how low-cost airlines are making more profit than long-haul airlines!!


texts: Why don't Transport Category aircraft have a listed Vy?

texts:
I was talking with a pilot about an inability to maintain the targeted climb rate in a particular situation and asked him what the Vy was for the jet.  He curtly replied "Vy is only for Part 23 aircraft." (FYI for those outside the US:  Part 25 aircraft are commerical planes, while Part 23 are usually general aviation planes. You can find more details here.)

Yet, I know for a fact that there is a maximum excess thrust speed, because at a certain speed drag is at a minimum. This should be close to Vy.  I also know that rate of climb is frequently listed for these aircraft. However, the optimal speed for gaining altitude isn't usually listed for commercial aircraft like it is for GA aircraft.   In fact, many of the v-speeds like Vmca and Vdec are harder to find for larger aircraft.

Why is this?  I can think of several possibilities:

Commercial aircraft speeds are defined by ATC and operating procedures, not by performance considerations
Commercial aircraft have enough thrust that climb performance limits isn't an issue (which I doubt from my experience).
Commercial aircraft use other parameters for similar purposes like rate of climb, v2, or long range cruise speed
Jets don't list this speed but propeller planes do


texts: What is the bank angle that should be sustained to move in a uniform circular motion?

texts:
I want to deduce the rate of turn of targets that move in a uniform circular motion. The radius of the different circles are known in advance. I have searched for my question and found the following formulas to help me:
$$R=\frac{V^2}{11.26\tan\theta}$$

$$\omega=\frac{1,091\tan\theta}{V}$$

The variables used are:

$V$ = true airspeed in knots
$R$ = turning radius in feet
$\theta$ = bank angle in degrees
$\omega$ = rate of turn in degrees per second

As we see from the previous equations that we can get the velocity from the first equation and then substitute in the second one to get the rate of turn. But the problem in the bank angle, how can one put a reasonable values for this angle on different radius. Of course the targets that rotates in circles with small radius will different from that moves in a large radius each one will have its own reasonable bank angle and hence its own speed that it will fly with and hence its own rate of rotation.

Note:

all that because i am trying to sample the plane movement over different circles each T (secs). So i want the rate of rotation to be reasonable to be able to get enough samples to represent that movement. Also i have read that the civilian planes is different from the military ones, so it seems to be complicated topic. Any help is appreciated, thanks in advance.


texts: What does it mean when a track "straddles north"?

texts:
Have heard a couple controllers taking note of a track that "straddles north".  What do they mean?

According to Google, the definition of the verb straddle is to extend across or be situated on both sides of.  Cannot see how this would relate to a track.


texts: What am I doing wrong in this RBI exercise?

texts:
The GYRO indicates the flight direction of the aircraft.

The RBI indicates where the non-directional beacon(a location on ground that’s sending the plane signals) is located.

Top of the RBI is always North. The yellow arrow point towards the beacon, however this is relative to the flight direction of the aircraft.

I always seem to mix it up. Can someone explain what exactly am I doing wrong here?
I seem to be selecting the correct symbol but when it comes to the grid then I mix it up.


texts: Why are the cabin chimes one semitone lower on the Boeing 747-400 than on other aircraft?

texts:
I noticed that the cabin chimes on the Boeing 747-400 overall sound one semitone lower than on other aircraft, including the 737, 777, Airbus A320, and even the 747-8. The same semitone-lower chimes are used on the Bombardier Q400, but that was built later.

Notice here that with the exception of some Qatar Airways planes using the "high" chime instead of the "low" chime for the seat belt sign, all the "low" chimes sound the same, with the exception of the Bombardier Q400. That chime is the same as the one on the Boeing 747-400.

Why is this the case?

Update: I noticed that this question was marked as being primarily based on opinions. However, it's not based on opinions. If you looked at the video links I supplied above, it is a fact that the cabin chimes on the 747-400 are lower-pitched than most other planes. All of the planes in the compilation video, except one, are at the same higher pitch. It's not just my opinion that they're lower-pitched. Also, if the answer is that "the chime manufacturer simply built it that way", that should be an answer. Questions shouldn't be closed based on the answer, the merits of the question alone should be judged.


texts: When were flares first used as IR countermeasures, and by whom?

texts:
I've been trying to find the history of flares (as countermeasures to heat-seeking missiles), but have not had much luck. Closest thing has been this wiki article which has but a single sentence in its history section saying "First deployed during the Vietnam War", with an explicit "citation needed" tag.

Another article is also surprisingly void of history details, and doesn't even have a history section.

Who first conceived of flares as IR countermeasures? When and where were they first used on a large scale?

The only hint I have is that the AIM-4 Falcon was the first IR-seeking AA missile to enter service, doing so in 1956. So presumably flares would not have shown up until that year or later.


texts: What's the idea behind leaving control of slats and flaps to pilots in autopilot?

texts:
When you watch airliners' flight videos on Youtube, you see pilots still control the slats, flaps and landing gear during the climb and landing phases even after autopilot is engaged. Why doesn't autopilot simply control them when it is capable of it with help of the FMS? Why is
their control still left to pilots, who anyway depend on the FMS (if they have one) to figure out the "right" configurations?


texts:
In current missile, what is the guidance law used at terminal phase in homing missile guidance?

eg: Proportional navigation, Augumented PN, Optimal Guidance Law, etc

At what distance the terminal phase guidance engage for Air Interceptor Missile(AIM) { eg: sidewinder, Derby, etc }. This is for active seeker(radar). And what is the terminal phase guidance used for active (radar) seeker.

what are information get from seeker to guidance system at terminal phase using active seeker(radar), other than Line_of_Sight(LOS) and Relative range(R) between missile and target.


texts: Why are there no blended-wing passenger airplanes in operation?

texts:
Blended wings are more beneficial when it comes to fuel efficiency increase and noise reduction. However, no manufacturer has decided to produce these airplanes for major airline operation so far. What are the inhibiting factors in the industry for not using this configuration?

From what I can guess:

It is a complete new configuration with low experience on it. High risk.
Aircraft will be in VLA sector (>500 passengers), a sector not very attractive nowadays.
The 90 seconds evacuation limit needs to be observed.


texts: What would cause an RPM drop and engine cutoff after starting a Cessna 152?

texts: My flight school's Cessna 152 is 30 years old. After refueling, the engine RPM went down and down. I tried putting full throttle in but it just stopped. Was it air in the fuel line or something more serious?


texts: How do pilots avoid clouds under night VFR?

texts:
When flying under visual flight rules (VFR), pilots have to be able to see far enough away to be able to avoid running into other aircraft or the ground.  Therefore, VFR flight requires good visibility with a high (or no) cloud ceiling; this is known as visual meteorological conditions (VMC).  It also requires that pilots avoid clouds like the plague, since clouds (on Earth, at least) tend to be on the opaque side, and a cloud that you can't see through could potentially be hiding something that it would be very bad to run into (such as someone else's aircraft).

Avoiding clouds is easy enough during the daytime, if the weather is good (the big white things tend to be fairly visible as long as you aren't actually inside one), but, in many countries (including such biggies as the US, France, and Australia), VFR flight is also permitted at night.  As clouds are not usually polite enough to illuminate themselves for the benefit of nearby pilots, they tend to blend in rather well with the dark sky (except sometimes when bright moonlight is present), the only hint of their presence being that they occlude background stars (which provides absolutely no information about whether those stars are being hidden by a small cloud close by, or by a big cloud further away, and depends on the stars being easily visible to begin with [which is not always the case, even at night]).

So how do pilots avoid clouds when flying VFR at night?


texts:
I have been scouring the web for resources on aero-engine structures and structural design (preferably civil turbofans) but unfortunately it seems like they are hard to come by. I would like dedicated texts on stuff like engine loads, what the major load-bearing components are, engine-airframe integration, what modelling techniques are used (from simple analytical/empirical models in prelim design all the way to perhaps advanced thermomechanical FEA), what the design considerations are etc.
I figured that most of this info might not be in the public domain because of trade secrets and such, but I was wondering if anyone could still point me in the right direction. I've been trying to piece together my understanding through reading some of the AIAA and ASME papers and even some of the OEM patents but would also like more comprehensive texts like the ones in https://www.ae.msstate.edu/tupas/SA2/Reference.html for general aircraft structures.


texts: What flight and route information do pilots need for flight?

texts:
A pilot needs some information before and during flight like METAR, TAF, NOTAM's, Charts, Frequencies, and so on. I want to build someday ,when I have enough time, a website, for private use (Flight Simulation), and maybe when I get the project to work good for public too, that displays all of that data. One should be able to input Departure and Arrival Airport and then get displayed all the Information named above about those two airports. The real question:

What do pilots still need except the above named? Have I forgot something. What would you implement, what would you like to have that makes your pilot (real or flight sim) life easier? Do you know a nice option in the GARMIN G1000 that could be implemented. But please only possible things. An artificial horizon is nice and would be even possible more or less but is very hard to program and is useless for flight simulation.


texts: Are TI graphing calculators permitted on the FAA knowledge exams?

texts:
I know it's a bit odd, but I like using my TI-89 graphing calculator in addition to an E6B when doing calculations. It helps me avoid dumb arithmetic errors.

I read the section "Use of Test Aids and Materials" of  Recreational Pilot and Private Pilot Knowledge Test Guide (FAA-G_8082-17). It seems to meet all of the requirements except (d), which I don't really understand:

  The use of magnetic cards, magnetic tapes, modules, computer chips, or
  any other device upon  which pre-written programs or information
  related to the test can be stored and retrieved is  prohibited.

Does anyone have a definitive answer on whether these types of calculators are permitted?


texts: How does an API (air position indicator) work?

texts:
I was looking for WW2 aircraft indicators and I found one navigation equipment called API (air position indicator).
But I couldn't find how it works exactly????


texts: How to compute quaternions from raw IMU and magnetometer data?

texts:
I have raw accelerometer data (w_ib^b) and magnetometer data from a UAV test flight. I would like to reconstruct the quaternion dynamics of the UAV without accumulating error from integration.

The method I was using involves solving the following integration: d(q_b^w)/dt = 0.5*Omega(w_ib^b)*q, where Omega(w_ib^b) is of the form: [-skew(w_ib^b) w_ib^b; -w_ib^b' 0].

I was wondering whether there was an alternative method of computing the aircraft attitude given raw angular velocity and magnetometer information from a UAV?


texts: Why does the LP compressor rotate in the opposite direction of the HP compressor?

texts: Why does the LP compressor rotate in the opposite direction of the HP compressor in some multi-spool turbine engines?


texts:
Under the trailing edge, there are 3 features, as seen in the picture. What's the name and the purpose of them?
The chord line is the distance between the leading and trailing edge.
What's the name of the upper and the lower surface of a wing?


texts: Safety measures to prevent pilots causing passenger planes to stall

texts: Why is it possible for pilots of commercial airliners to execute manoeuvres virtually guaranteed to cause a stall?


texts: Why generation of lift is more at mid span of the wing?

texts:
For the same condition like same density, wing area, free-stream velocity, From the above figure one can see more pressure differential and hence more lift at mid span of the wing?
What causes this phenomenon? Is it due to influence of tip vortex?


texts: Was ATC overstepping its boundaries when advising a pilot to ignore a cell warning?

texts:
I found a clip on YouTube (via an article on Jalopnik) of an Aer Lingus pilot departing from JFK. Due to a weather cell showing up on his instruments, he can not make the left ATC asks him to make.

ATC advises him that the weather is not as bad as the pilot makes it out to be.

  ATC: "Shamrock 104 heavy, it's light. I have 6 categories of weather here, it's the lightest category. I've had no adverse ride reports south of the airport by 10 miles."

He then is put in a holding pattern (while departing) until the situation is resolved. He is then told that the last 6 craft departing had no problem following that heading.

  ATC: "Shamrock 104 heavy, you're gonna go the way the last 6 GREKIs went while you did this overhead Kennedy."

Was ATC overstepping its boundaries advising a pilot to ignore a weather warning?


texts: In Antonov An-225, why there are radioactive / nuclear signs?

texts:
Looking at some An-225 images, i see some radioactive signs near the nose radome. Why they are there? I'm sure it doesn't have a nuclear reactor on board or any nuclear medical equipment. The only thing that comes to mind is nuclear density gauges or something related to the radar. Does other planes also use radioactive materials for the same purpose? I've never see, read or heard of any plane using radioactive materials except for propulsion.

Images source:

https://gelio.livejournal.com/193025.html

Find this link on this answer:

Does the Antonov An-225 have an Auxiliary Power Unit (APU)?

https://en.wikipedia.org/wiki/Nuclear_density_gauge


texts: What happens when the eigenvalues of the longitudinal A matrix in dynamic stability analysis, are NOT two sets of complex conjugate pairs?

texts:
The complex conjugate pairs of eigenvalues of the longitudinal A matrix characterize phugoid and short period dynamic responses, this information is well established.
My question is - what happens when the eigenvalues consist of 2 real roots and 1 complex conjugate pair?  Can this happen (assuming no error on input, or does it only happen with an error?) and if it does what does this say about the dynamics of the system?  Examining the eigenvectors I'm wondering how to interpret two eigenvectors that consist of all real values?

Thanks!


texts: Is the time pilots are commuting considered rest time?

texts:
Pilots operating under FAR Part 121 assigned to domestic routes are required to have a certain amount of "rest" time before beginning a flight.  Further, the maximum  "flight time," (where the pilot is not resting or on duty) is constrained within specific periods such as monthly, yearly, etc.

If a pilot lives in Florida, but is based in and originates flights from California, is the time spent commuting (from Florida to California) to begin a flight considered part of the FAR required "rest" time?


texts: Can Air Traffic Controllers participate in Q&A?

texts:
While asking the question in chat How do we get controllers on the site? @egid suggested there may be FAA or union restrictions on participating in Q&A. That would be sad since pilots and controllers communicating with each other improves safety and efficiency... but certainly doesn't mean it isn't true.

Does anyone know of specific restrictions placed on controllers by the FAA or NATCA (National Air Traffic Controllers Association) which would prevent them from answering questions on this site?

I realize this blurs the line slightly between the main site and meta, but I'm asking about legal reasons, not speculation about why we haven't attracted any controllers yet (that I'm aware of).


texts: Why are Flight Directors turned on so early?

texts:
I have noticed that the requirement to turn on the Flight Directors in a commercial aircraft is in one of the very first checklists. Why does this have to be the case when the Flight Directors are really just an indication of where the aircraft needs to fly to?

Why, for instance, is it not in the "Before Take-off" checklist?


texts: What exactly is an FBO and what services are provided?

texts:
To most non-U.S. pilots who have little or no experience flying in the U.S., the concept of a FBO is not very well understood.

What exactly is a FBO and what are the services that it can provide? I've heard that they can refuel your plane, move it to a hangar, clean it, provide preflight planning facilities, etc.

Is there a charge for these services (I guess so) and if so, what can be expected? I've also seen many airports with multiple FBOs. How does that work?

All I know is that FBO stands for "Fixed Base Operator".

This may seem like a very stupid question but in Europe there's no such thing. If you need fuel you either taxi to the pump and fill up or call up the fuel provider (if you're lucky because they usually only serve private jets).


texts: How do dummy bombs simulate real bombs in training when they're so much smaller?

texts:
This picture shows a couple of Mk-76 25lb (11kg) Inert Training Bombs on a McDonnell Douglas AV-8B Harrier II; it's clear that the physical characteristics of the dummy bomb are quite different to actual munitions.

source

The manufacturer says these bombs are "used to simulate the MK-82 in low drag configuration". The venerable Mk-82 is typically 500 lb (227 kg): here's an F-16 with Mk-82s for scale comparison:

source

One obvious advantage of the smaller, lighter bombs is that they're vastly cheaper to operate, both in terms of handling on the ground and the amount of fuel you'd be using in the air. However, the dummy bomb is 20 times less massive than the bomb its designed to simulate: its small size and weight surely mean their aerodynamic characteristics are very different to the bombs they're supposed to be simulating. (I know that speed of fall in a vacuum is not dependent on weight, but a falling object in air is affected by shape, weight, drag etc.)

My question is - since their purpose is presumably to help train the pilots, how can tiny dummy bombs usefully simulate real bombs?


texts: Possible military aircraft ID, N. Carolina

texts: I was recently in Oak Island, NC and saw the following plane flying above. It was low-flying and much louder and larger than the other small prop planes flying out of nearby Cape Fear Regional Jetport. Based on the size of the propellers I suspected it was some kind of military aircraft but wasn't able to figure out what it was. I know this is a small, dark picture, but does this plane look familiar?


texts: Why do all new European fighter jets have delta wings?

texts:
Why do all new European fighter jets - Typhoon, Gripen, Rafale have delta wings? As I know, they were all designed separately. And they are not new either.

Is there any particular advantage that caused the Europeans to choose to do it like it is? Is it because of traditions? Or do they use the same software? (cheeky grin)


texts: Where to get Initial EASA Class 1 Medical?

texts:
Can somebody suggest a list of EASA medical centers, where I can get Initial Medical 1?
Any EASA county is OK.
I'll appreciate any links, thank you!

Amendment:
I've found lists of AMCs or at least medical examiners approved by CAA for the following countries: UK, Spain, Serbia, Poland, Finland, Croatia, Ireland, Malta, Switzerland, Romania, Greece, France, Danmark

Full list of EASA countries and list to it's CAAs can be found here. And some of examiners all over the EASA here.

Does somebody know about other countries like France, Germany...? I have not found any lists of AMCs approved by CAA or at least medical examiners for these countries


texts: When modeling a shear flow for dynamic soaring, is the coefficient always a constant?

texts:
Is a wind shear model for dynamic soaring always given by the velocity vector field:
F = < cy, 0 >,
where c is constant?
I've tried modeling c to introduce a decay in magnitude of the wind shear as it moves from left to right, but apparently this violates conservation of mass of the flow (assuming the flow is incompressible) and that the coefficient should be kept constant.


texts: How can I legally organise a high school football game flyover in Delta airspace?

texts: If a high school had given permission for a low pass over a football game, would the controllers also give permission? The school is about 3-4 miles away from the class D airport. Also, would you have to still stay at least 500ft above ground? I'm assuming you would still have to even if the school is allowing lower because that is the law.


texts: What are the fields of the ground reply (uplink) to a weight-and-balance request?

texts:
I am trying to send from the Aircraft MCDU AOC menu (via ACARS Data Link) , a Weight/Balance Request downlink to the Ground Station .

I would like to know what are the fields that make up the uplink message to reply to this request ?


texts: Can a commercial jet with two engines, fly on one. If so, what are the limitations. Maby some are better than others in this situation


texts: What training is required for a class B endorsement?

texts:
14 CFR 61.95 requires solo student pilots to have an endorsement to (a) fly through class B airspace or (b) takeoff/land at a class B airport.  However, the requirements to get it are pretty vague:

(1) The student pilot has received both ground and flight training from an authorized instructor on that Class B airspace area, and the flight training was received in the specific Class B airspace area for which solo flight is authorized;

There are similarly vague training requirements for Recreational pilots in 14 CFR 61.101(d) and Sport pilots in 14 CFR 61.325.
Is any particular content or amount of time expected, or is it at the CFI's sole discretion to decide when a given pilot is competent enough to endorse? Does the training itself need to be logged as such, separate from the endorsement?


texts: How does a departure off a runway used for LAHSO operations work?

texts:
Let's say that LAHSO operations are in effect at Long Beach (KLGB). Runway 12/30 has a hold short line short of runway 8L / 26R. If an aircraft is cleared to land runway 30, and LAHSO operations are in use, I get that.

But how do operations work for departures off of runways that have a hold short line painted on the runway? If an aircraft is cleared for takeoff runway 30, is the aircraft expected to disregard the hold short line at the departure end of the runway and use full-length?

Source: bing.com


texts: What are the bumps in the F-22 Raptor wing for?

texts: As you can see in the picture there are several bulges or bumps in the wing that are located in the aileron and flaps. Somebody told me these are to hide the linear actuator, pushrod, and control horn. However, if the bulge is connected to the wing and aileron how is it possible for it to be there? If the aileron is moving independent of the wing, how is the bulge connected to both at the same time?


texts: Are new airliners less safe than older the two first years after they are marketed?

texts:
Looking at the 2014 Allianz Global Aviation Safety Study for airliners:

The last generation of aircraft (1974 and forward, including A320 and B737) have a very low rate of accidents: less than 2 accidents per million of departures. This rate is better than all previous generations.

However this rate is lower only one to 2 years after the model has been on the market. Prior to this milestone, the rate is higher than previous generations, except the very first one.

Why is the first year rate of accidents so relatively high? It seems we have almost the same number of accidents before two years, than during the rest of the aircraft life.
Is there an obvious reason for having aircraft of the last generation apparently less safe at their life beginning than the two previous generations?


texts: Can I act as SIC with these specific type ratings?

texts:
Can I act as SIC on a part 91 ferry flight, if I hold...

a DC-9 type rating and the flight is in an MD-80?
a B-737 type rating, can I act as SIC on a B-737NG?


texts: What will create a "traffic puck" on the UAT band?

texts: I know that for ADS-B in the US to receive TIS-B information you need to be a participating aircraft (ie ADSB-Out).  My question is more specifically, if you are flying an aircraft with a 1090ES transponder and have a stratux or similar ADSB-In device for your phone or tablet, will the system create the traffic puck around your aircraft and send TIS-B information for you?


texts: Why is carburetor heat use discouraged on the ground?

texts: I've been reading my private pilot books for when I start in February and Carb Heat has me stuck in a rut. I feel like I need to have a very solid understanding of this being that I live in a very humid area. The book says do not use carb heat on the ground and on taxi because it will draw unfiltered air into the engine(air from exhaust)... But what is the difference between using it in the air vs on the ground and isn't the risk of icing just as equal in the air as on the ground?


texts: What are these long tubes under the wings?

texts: I wonder what are the elements below the wings (pointed by the black arrows in the image). I'm not referring to the sticks at the end of them, which I found them to be "static wicks", used for static electricity discharge.


texts: Is white/brown-out effect hazardous during the landing roll out?

texts:
Landing on unpaved runways or runways covered by snow or dust causes a white/brown-out visibility restriction.

Does it disrupt the pilot's visibility during the roll out in a fixed-wing aircraft?


texts: What is this "flap-like" thing on the back of the F-15?

texts: I saw an image of an F-15 landing. What is that flap-like thing in the top of the plane in this picture? I couldn't find it on any other pictures or drawings of this aircraft.


texts: Why is the fuel:air ratio of a turbojet engine not around ~1:15 (the stoichiometric ratio)?

texts: Also, what is the maximum fuel:air ratio possible in a combustion chamber of a jet engine?


texts: What is the origin of the practice of numbering runways by magnetic heading?

texts: Today, runways are always named according to the magnetic heading. How did this practice start? When and where was the practice invented? Whose idea was it, and how did it catch on?


texts: How did Charles Lindbergh use dead reckoning over the Atlantic ocean?

texts:
Wikipedia and other sources assert that Charles Lindbergh used dead reckoning on his historic flight from Long Island to Paris but—likely being aimed at a broader audience—are short on specific technical details.

With few or no landmarks to use as references, how was Lindbergh able to stay on course while over the Atlantic ocean?


texts: Does the aerodynamic center move when flaps and slats are deployed?

texts:
Does the aerodynamic center of an aircraft move when flaps and slats are deployed?

I am trying to figure out if the AC of an aicraft moves with landing and take-off configurations. I know Cl and Cm change a lot, but I can't find a reference where the movement of the AC is discussed.

I've checked Roskam, Anderson and Aerodynamic Characteristics of Wing Sections and it seems like the AC position doesn't change only with flaps but they don't show examples of wings with flaps and slats.


texts: Why are magnetized materials dangerous goods?

texts:
I was reading about Dangerous Goods, and came across the fact that magnetized materials are classified as Dangerous Goods (item 12 in the linked page). We all see magnets every day, and they seem harmless.

Why are magnets dangerous to airplanes and require more careful handling?


texts: Is a wind speed of 150 km/h dangerous during a flight in an Airbus A321?

texts: I am just curious about this... during one flight on Airbus A321 we experienced turbulence and the pilot told us that the wind speed is 150 km/h, so we won't get drinks and snacks due to safety reasons. The question is: Was that wind speed 'normal' or 'dangerous'? What could happen?


texts: Are the implications of weight and balance for rotary wing aircraft similar to fixed wing aircraft?

texts:
Original discussion here.

How does weight and balance for rotary wing aircraft work?  Is lateral CG more or less of an issue, or is it comparable to fore/aft CG since the lifting surface is rotating around the aircraft?

What are the major differences compared to fixed wing, if any?


texts: What is the purpose of air that passes through the engine core in a turbofan engine? Is it mainly to spin the fan rotor?

texts:
The majority of the air going through the bypass is producing most of the thrust and providing the air that cools the engine.
Does is also provide the pressurization and cooling/heating for the cabins?
What is the purpose of the air passing through the core? Is the objective to spin the fan rotor even though it still produces thrust? Does it provide air for any other purpose such as cooling?


texts: What are the lowest authorized minimums for each ILS category?

texts: I have been recently told that ILS minimums were changed some time ago. Could anyone tell me what the lowest authorized ILS minimums are for CAT I, CAT II, CAT IIIa, CAT IIIb and CAT IIIc? I'm interested in FAA, EASA and ICAO standards.


texts: Where is fuel metered in continuous flow fuel injection system?

texts: How is fuel metered in continuous flow fuel injection system?


texts:
Why is Mi-35M so huge in size?

What is the benefit of having an attack helicopter to be so big?

If there is no benefit, why wasn't its size reduced?

Apache is not as huge as this.


texts: Which busy commercial airports have a very large GA operation attached?

texts:
I was thinking about OAKland International, and how the General Aviation side of the field is much larger than the commercial side, but the commercial side is still very significant.   How many others are there like that?

I don't mean the many GA fields that get occasional visits from a "United Express" or "Delta Connection" rubberband turboprop.  Let's say the criteria are

Commercial and GA operate on separate "sides" of the airport, e.g. Most commercial traffic uses one area and runway(s) and most GA traffic uses another area and runway(s). Not John Wayne/Irvine.
They are physically connected by taxiways, not separate airports.
The commercial side serves over 100 flights a day of A318/B735 or larger (so not Long Beach or Billy Bishop), and is big enough to be a hub airport for a network like Southwest or Ryanair.
the GA side doesn't necessarily dominate over the commercial side, but it has the ground infrastructure to do so if the demand were there.


texts: Again, where is the pivot point in pitch

texts:
In regards to recent question about neutral point, as being defined as center of lifts from wing and tail, could one also define a "neutral point" for down forces CG AND down force (up elevator) from tail.
Lift force is now only from wing

Notice if the down force center is behind the lift center, the nose pitches up.  Would the center of this rotation be at the wing, at the center of all moments (between Clift and Cdown), or somewhere else?


texts: What is a skidding turn (vs slipping turn)?

texts:
I am trying to understand the concept of

1) What qualifies a turn to be skidding or slipping

2) how we need to give elevator back pressure if we do not want to 'slip' the turn.

While browsing for answer I read that skidding occurs in the absence of back pressure. Why does it occur when there is no elevator back pressure. I understand that when you bank to turn, you reduce the lift component and not giving back pressure might make the aircraft nose low.

But how does that make a skidding turn. Also what causes the turn to slip?


texts: Why Black Boxes are not capable of transmitting its Critical Data directly to satellite?

texts:
Why don't airplane include a satellite technology to upload the critical (Voice/Engine etc) data recorded in FDR to satellite. This would be very useful, in case of missing FDR.

Is there any technology/Equipment existing on this issue?

Note: FDR can just to start transmitting the very latest data first followed by old data in sequence before aircraft gets into crashing mode. Probably we do have some specification/limits to determine the aircraft crashing probabilities. Even if FDR is missing from the crash site we will have some limited data(might not be complete data) which got stored after crash trigger.


texts: Does full nose up trim yield best glide in Cessna 172/152 for a given load?

texts:
I heard from a ground instructor that full nose up trim will yield best glide in a 152 and 172.

As I understand best L/D, a lighter loaded plane will require a slower glide than the same craft loaded more heavily.

Am I correct in thinking that the best glide in the POH is an average glide for an average load?

Was my ground instructor correct? Those extra feet may be useful one day!


texts: Is the pod on the right wing of the PC-12 and Cessna 208 a gyrocompass?

texts:
Hello avgeeks,

First time posting here looking for an answer.
Could someone tell me what's located inside that pod on the right wing of some planes like this Pilatus PC12 or this Caravan 208?
I guess it can be a gyrocompass but i am not 100% sure.

Thank you in advance!!
Safe landings.


texts:
From what I can tell, this is the method of creating a temporary ICAO address in the 978Mhz UAT protocol:

From https://www.icao.int/safety/acp/Inactive%20working%20groups%20library/ACP-WG-C-UAT-2/UAT-SWG02-WP04%20-%20Draft%20Tech%20Manual%20V0-1%20.pdf

  3.2.1.5.1.3.2

  Self-Assigned Temporary Address of Transmitting Aircraft An “ADDRESS QUALIFIER” value of ONE (binary 001) shall indicate that
  the message is an ADS-B Message from an aircraft, and that the
  “ADDRESS” field holds the transmitting aircraft’s self-assigned
  ownship temporary address.

  The self-assigned temporary address shall be generated as follows:

  Let:

  ADDRP = the ICAO 24-bit address that has been assigned to the aircraft;

  ADDRT = the temporary address that is to be generated;
  M(1) = the 12 least significant bits (LSBs) of the ownship “LATITUDE” field (per §3.2.1.5.2.1) at the time the temporary address option is selected;

  M(2) = the 12 least significant bits (LSBs) of the ownship “LONGITUDE” field (per §3.2.1.5.2.1) at the time the temporary address option is selected;

  M(3) = 4096 × M(1) + M(2);

  TIME = the number of seconds that have elapsed since UTC midnight
  at the time the temporary address option is selected, represented as a
  24-bit number.

  Also, let “⊕” denote the modulo 2 bit-by-bit addition(or “exclusive OR”) operation.

  a. If the transmitting aircraft’s ICAO 24-bit address ADDRP is available, then the temporary address ADDRT shall be the modulo 2, bit-by-bit summation of the permanent address and M(3), that is:

  ADDRT = ADDRP ⊕ M(3).

  b. If the aircraft’s 24-bit ICAO address ADDRP is not available, then time of day shall be used as an additional randomizer. In that case, the temporary address ADDRT shall be the modulo 2, bit-by-bit summation of TIME and M(3), that is,

  ADDRT = TIME ⊕ M(3).

So the question is if this is deterministic.  Could one work their way back to the actual tail number when an aircraft is in anonymous mode?


texts: What airports close to the east coast of the US have attractions that are easy to get to?

texts:
I'm currently living in Boston and fly out of KBED regularly. I'm looking into making a long cross country in a Cessna 182T to the Bahamas and am planning my route. I'm IFR rated.

I'm looking for airports generally along the east coast (east of KATL and south of KBED) that have at least one of the following and are less than a 25 minute drive from the field: diner/restaurant with at least 3 stars on yelp, museum, historic or tourist attractions.

Some places that have caught my attention:

KBID (Block Island State, RI) - Bethany's Airport Diner is on the
field and has 4 stars on yelp
0B8 (Fishers Island, NY) - friend says
it's a 15 minute walk to a really nice golf club open to anyone
KMYR (Myrtle Beach, SC) - there's a 100 things to do walking distance from the airport (parks, beach, restaurants, tours, etc...)
KCHS or KJZI (Charleston, SC) - 20 minute drive to the historic downtown of the city

Really appreciate your input!


texts: How do I find out what happened on this flight?

texts:
On 2017-01-03 DAL58 from Boston to London apparently returned to New York after 90 minutes of flight.

This seems quite irregular to me, and I had expected to find details about this published somewhere. I tried Google, and I searched at avherald.com for the date and also for B763, but didn't find anything.

Was this not sufficiently irregular to warrant some kind of public information about what happened on this flight? Or if such information is published, where could I find it? Or is such information only available to certain people?


texts:
Do motor glider pilots ever "cheat" and use their motors to thermal?

I understand there are 2 types of motor gliders:

Self launching: with about 80 hp very similar to an ultralight except a lot more aerodynamic. They can self launch (takeoff) themselves without a tow.
Sustainers: with about 15 hp, they cannot self launch, but can use the motor to sustain flight to get home if they cannot glide all the way home due to lack of thermals, sinking air, etc.

I understand gliders soaring over fields spend about 20% of their time thermalling to get altitude.

Why not just put on the motor to thermal faster and spend more time gliding (assuming you're not a purist)?

Is this ever done?


texts: QF72: How could a disconnected autopilot change the pitch?

texts:
So I was reading about flight QF72, where the A330 had incorrect sensor data. The aircraft automatically pitched the nose down twice in response to abnormally high incorrect angle of attack data, but it did so AFTER the autopilot was disengaged. (See https://www.atsb.gov.au/media/51218/AO2008070_interim.pdf page 16-17).

How is that possible? Isn't it the autopilot that does that? I am probably getting the wrong idea about what the autopilot does, right?

Also, what would be the idea behind why the pilots attempt to correct the situation by pulling back the sidestick be unsuccessful at first, but suddenly have the desired effect right after he stopped giving that input?


texts: What does the “test result indicator” indicate on a cockpit voice recorder?

texts: I am really curious as to what the “green/red” strip of led indicate and the numbers below it. Having read around the web, i speculated that it could be an audio quality rating scale. Would help alot of someone could please help explain the “numbers” and why there is so many led blocks on the strip...


texts: Why is an elliptical wing planform so aerodynamically efficient in layman's terms?

texts:
Below is part of an answer to the post 'For the elliptical wing, what is elliptical, and why is drag regularly distributed?':

  On the untwisted elliptical wing the local lift coefficient is constant over span, and changes in angle of attack over the linear range will change the lift coefficient equally everywhere. This, when combined with the elliptical chord distribution over span, means that the circulation distribution will stay elliptical over the linear angle of attack range. This is the special characteristic of an elliptical wing: While any wing can have an elliptical circulation distribution at one angle of attack (given the right twist distribution), the elliptical wing will keep that elliptical circulation distribution over the whole operating range.

My question is: how can the wing tips of an elliptical wing be considered to produce the same amount of lift as the root (see emphasis above)?


texts: How to determine angle of bank caused by shift in centre of gravity in an aircraft?

texts:
I’m trying to figure out the angle of a bank caused by a shift in the centre of gravity of an aircraft. How should I do this?

What avenues should I go down to calculate this? I know that the plane will bank until c.g. is below centre of lift.


texts: Can composite materials be used on super-sonic aircraft?

texts: Can composite materials be used in aircraft that can fly super sonic.


texts: Why would a plane drop 14.000 ft mid flight?

texts:
Just noticed American Airlines flight 221 dropped 14.000 ft mid flight today. Curious, what could have caused this?

Here are the flight details.


texts: What are these aircraft at the Naval Air Weapons Station China Lake?

texts:
What are these 12 aircraft at the co-ordinates 35.677323, -117.676903?

I recognize the F-111 and C-130, but not the others.

Source: google maps


texts: What bank angle creates the least energy loss in an emergency engine out 180 degree turn?

texts:
A situation we all hope to never have:  engine quits at a low distance AGL.

What bank angle will produce the least altitude loss for a 180 degree turn?
Is this common for all aircraft?

Readings have shown the elevator/wing to be more efficient at turning the aircraft
than the rudder alone.

It would seem better not to try to hold altitude on the turn, but one still must avoid stalling
the wing.  Airspeed is also a factor in gliding efficiency.

What is the best way to turn 180 degrees with least loss of altitude?

Some good references provided.  Curious about rudder technique in a steeper bank. At 45 degrees, rudder is pitching nose down some, but should be there to "follow" the wing around the turn (lowest drag).  Some elevator, some rudder to swing the tail through the yaw plane, giving up some altitude, so as not to load the wing as much (like an emergency descent)?


texts:
Wingwalking is an aerobatic discipline with shows such as this one.
The definition of wingwalking from Wikipedia gives no other alternative than using biplanes:

  Wing walking is the act of moving along the wings of a biplane during flight [...]

(source: Wikipedia, as of 26 February 2020)

When searching for images on the web, I can only find biplanes, mainly stearman but also other biplanes.

For me, it seems that any aircraft with high wings or parasol wings can do the job, so why do they only use biplanes?


texts: I have a FAA Private VFR SE license based on my foreign license, and added IFR in my home country; how to upgrade the FAA license?

texts:
I already validated my non-US licence and got a FAA Private VFR SE Licence based on my foreign licence. I recently completed my IFR rating in my home country and was wondering how to 'upgrade' my FAA licence and add the IFR privileges?!

I tried my best to find something on google but I only found references to a "FAA Instrument Knowledge Test Foreign Pilots" without any details.

Any experience or pointers for me?


texts: What is this extension/device on top of the wing of this ultralight?

texts:
This a shot of the Aero Synergie Papango ultralight, the succesor of the Aero Synergie J300 Joker.

The wings are more elaborate compared to its predecessor's and include on their top two additional extensions/devices.

What are they? Any aerodynamic role or just for aesthetic sake?


texts: Can anyone help me with the Make, Model (version), and Unit of this WWII army trainer. Appears to be an AT-6 version

texts:
Location: Madison, WI Municipal Airport on May 21, 1939.
Notice the straight bottom on the vertical stabilizer, crest emblem, pitot tubes, landing gear, exhaust location, antenna, etc.
I have two photos of this plane, the 2nd photo is from the front, but I don't know how to add a second photo to this post.


texts: Where can I find old (historical) FIR map?

texts:
I'm doing a research with FIR Ho Chi Minh (formerly named FIR Saigon).

I've read a document which said:

During the Fall of Saigon, ICAO, in 28th of April 1975, had divided FIR Saigon into 3 AOR: Bangkok, Singapore and Hongkong, then they gave these AOR to the corresponded FIR.
In the 7th of December, 1994, ICAO sent AOR Bangkok and AOR Singapore back to FIR Ho-Chi-Minh.
In the 1st of November, 2001, ICAO gave part of AOR Hongkong to FIR Ho-Chi-Minh, and created AOR Sanya from the remained part of AOR Hongkong.
In the 8th of June, 2006, ICAO changed AOR Sanya to FIR Sanya

I managed to search those old FIR maps in the internet but no luck for me.

Hence, I would like to find out all historical FIR maps to make a comparison.

If it is impossible to find all FIR maps, old FIR maps of South East Asia FIR is greatly appreciated.


texts: Why does the canopy of the F-22 Raptor have a golden tinge?

texts: Why is gold used in the canopy of the F-22 Raptor?


texts: How should the crew callout 1,000 ft. prior to assigned altitude?

texts:
When climbing or descending in a multi-crew cockpit, most SOP's require a verbal callout at 1,000 ft. prior to the assigned altitude.

I typically hear different callouts by different people:

"One to go"
"Six thousand for seven thousand"
"Six thousand climbing seven thousand"
"Six for seven"

Is this just a personal preference kind of thing or is there an actual safety benefit to one or the other?


texts: How does the fuel pump work in a PA-28 and when should I use it?

texts:
Just started flying again after 14 years and I'm taking this to the finish line this time. All my time, up till 10 am today, is in a C172. I did fly a PA 28-151 today and liked it.
I do have some questions about Pipers (specifically PA 28-181 and 28-151):

Does the fuel pump has to be on the entire flight?
Is there a fuel pump for each tank?
If the pump doesn't have to be on the entire flight, how does the engine/carburetor get fuel considering the engine is higher than the wings?


texts: How is the RAT on the Airbus A320 family manually deployed?

texts: I watched Captain Joe's video on this topic but he only said in case the RAT does not deploy that you can manually deploy it from the cockpit, but unfortunately he never stated how this worked? (I'm only new to the industry and just an av geek)


texts: Why aren't contra-rotors used on the V-22 Osprey?

texts:
The Osprey has 38 ft (11.6 m) rotors in a rotating nacelle on each wing. The rotors are powered via a gearbox as in usual turbo-pro fashion.

Is any reason that is obvious that smaller contra-rotating rotors wasn't adopted. It is noted on Wikipedia that the rotor diameter is currently 5 ft (1.2 m) below ideal, wouldn't a contra format be more compact on this front.

  Due to the requirement for folding rotors, their 38-foot diameter is 5 feet less than optimal for vertical takeoff, resulting in high disk loading.


texts: Why was this commercial jet accompanied by small plane near Seattle?

texts:
From the South Beach Campground on the western shore of the Olympic Peninsula in Washington State we observed this unusual formation:

I only had a Sony RX100 at hand but perhaps the image quality is sufficient to recognize the airplanes.

The picture was taken on July 23rd, at 20.20h PDT (the image timestamp is 6 minutes off), looking roughly NNW. I don't dare guess the altitude, but to the bare eye the small airplane was a mere dot. The two planes flew in formation in a circular counter-clockwise pattern around the north-eastern part of the Olympic Peninsula. They re-appeared two or three (I think three) times. They appeared to fly at low speed.

We realized that we were only approximately 150 km west of Seattle, the Boeing headquarters. Was this a test flight? Which planes are involved? What is the function of the small accompanying jet?


texts: How do I tell ATC that I don't have a transponder?

texts:
If my plane doesn't have a transponder and ATC tells me to squawk some transponder code, how should I respond? Is it just as simple as "I don't have a transponder"?

This is for the United States and for a plane with no electrical system, and obviously at a towered field where I would be communicating with ATC using a portable radio. No flight plans will be involved and I will generally be flying out of a class B field but within a class B umbrella. Flights will be VFR/daytime only.

EDIT: Looks like I opened up quite a can o' worms, here. I didn't know it would be this complicated. Just found this, too, which adds some more info. Thanks for the lively debate and the good suggestions.

https://www.aopa.org/training-and-safety/pic-archive/equipment/transponder-requirements

Looks like it's getting more and more difficult to escape government control. I think I may have to get a transponder. Hmmm.


texts:
If an airway is marked unusable, why publish it?

Secondary question, can RNAV still be used?


texts: For a private GA pilot, when is an endorsement needed for a particular type of aircraft?

texts: If I've done my training say 85% in a C152 and 15% in a C172, then upon my earning my PPL, what am I allowed to fly legally?  I assume the 152, but not sure about the 172. Is this indicated somehow in my logbook? When is a separate check out required for a new airplane and assuming the same type (i.e., SEL, fixed gear, fixed pitch prop, non pressurized, etc.), what would this typically entail?  Is this an FAA requirement or a liability requirement for clubs, etc.?


texts:
Can anyone suggest a good airfoil for racing the F4U Corsair? I'm building an RC model but I want it to be fast unlike scale warbird. Any suggestions on wing design and airfoil would be greatly appreciated. I know I can always throw more power to it but I want the fuselage and wing designed to match.

Thanks


texts: How does hydraulic actuator servo valve feedback work?

texts:
The book Aircraft Systems uses the following diagram for a mechanically controlled hydraulic linear actuator (for moving a control surface e.g. an aileron):

The following explanation is given about its operation:

  As the pilot feeds a mechanical input to the flight control actuator, the summing link will rotate about the bottom pivot, thus applying an input to the servo valve. Hydraulic fluid will then flow into one side of the ram while exiting the opposite side resulting in movement of the ram in a direction dependent upon the direction of the pilot’s command. As the ram moves, the feedback link will rotate the summing link about the upper pivot returning the servo valve input to the null position as the commanded position is achieved.

However, I fail to understand this explanation given the diagram. If the mechanical signal is to the right, the summing link will slant to the right (i.e. /). I assume this is a command for the cylinder to move to the right. When the cylinder moves to the right, the feedback link causes the summing link to eventually return to the upright position (i.e. |). But when this position is achieved, the Servo Valve (SV) input is now more extended than it was before (the whole summing link is now upright but with a net shift to the right). How is this the null position that would cause the SV to close?

In search for an answer, I came across a better diagram which makes sense with a sliding sleeve of the SV (but this diagram is in my opinion not what the first figure illustrates):

]]

Is the first figure simply a poor explanation and the second figure is more representative of how these hydraulic linear actuators work?


texts: What do FAA DERs require regarding low-level requirements in DO-178C?

texts:
Software developed for aircraft needing TA certification pretty much has to be done using a process following RTCA/DO-178C.  My question regards low-level (sometimes called "derived") requirements:

Low-level requirements either refine high-level requirements, or express design decisions.  I've been told a low-level requirement should be traceable to some statement or small block of code, and at DAL C and above, each piece of code needs to be traceable to a low-level requirement.

Do DERs want to see a test corresponding to each low-level requirement, or is that only so for the high-level requirements?  Would it be OK to do testing at a function level ("unit testing") as low-level requirement testing, and are the DERs happy with that?


texts: How to avoid shock (particularly Oblique shock) inside Cd nozzle?

texts:
Using the Area ratio (A/A*) and for the desired exit Mach number I have designed a cd nozzle. The Inlet total pressure (Po) and the total temperature (To) is calculated using Isentropic relations for the optimum condition.

FLUENT CONDITIONS:

Solver type: Density-based, Absolute, 2d, Axisymmetric

Model: Energy On, Inviscid

Material: Air (Ideal gas)

Boundary condition:
Inlet- Pressure inlet- 792812.3356 Pa; Supersonic/Initial Gauge pressure: 790000 Pa; Total Temperature: 518.4 K

Outlet- Pressure outlet- 101325 Pa; Backflow total temperature: 288 K

Operating condition- 0 Pa

For this condition, I should get an ideal flow throughout the nozzle, but there's an oblique shock inside the cd nozzle. Is this a design flaw or any error in the ANSYS fluent conditions?

How to avoid Oblique shock inside CD nozzle?


texts: Can a plane with a thrust-to-weight ratio less than one fly vertically and perform loops?

texts: In the game Battlefield 1 you can fly a Sopwith Camel vertically and perform different kinds of aerobatic maneuvers like loops. According to its specifications, its thrust-to-weight ratio should be about 0.28 and hence it should not be able to fly vertically. Can it?


texts: Do companies based in non-English-speaking countries require intra-cockpit procedural communication to be performed in English?

texts:
I was watching a video of an MD-11 landing in Quito, Ecuador

The crew is German (Lufthansa).

When they speak with ATC it's in English (obviously).
When they speak with each other it's in German (also obvious).
But, when they go through flight procedures, they speak in English.

Why do they not speak in German?
Is this required for the Cockpit Voice Recorder?

In this exchange the pilot is talking through part of the approach with her copilot, who then says

  Genau

which means "I agree" in German, then immediately afterwards he says

  Gear down

notice how both sound very similar.  Further in the flight the copilot, calls

  Flaps 50

why not

  Flaps fünfzig


texts: Why is the flight duration of the same flight different in different months?

texts:
For example:

CX880 (HKG TO LAX) takes 13h40m on the 2nd of August, but only takes 12h50m in September.
CI008 (TPE TO LAX) is the same; it takes half an hour less in September than in August.

What are the factors that cause this difference?


texts: What does this A320 FCTM quote about cold weather and non-precision approaches mean?

texts:
Can someone explain this paragraph from the A320 FCTM about minimum temperatures for non-precision approaches? I can't understand it.

  COLD WEATHER OPERATIONS For all Non Precision Approaches, there is a minimum OAT. Below this temperature, the error on the barometric
  altitude is no longer acceptable, and altitude should be corrected in
  temperature. As it is not authorized to make these altitude
  corrections to the final approach segment of the FM Flight Plan
  (F-PLN) through the MCDU, it is not possible to use FINAL APP when OAT
  is below this minimum OAT. The flight crew must then use selected
  vertical guidance. This minimum OAT is indicated on the approach chart
  or must be defined by the operator based on the terrain profile (plus
  adequate margin).


texts: How are the dimensions of the empennage determined for jetliners?

texts:
How is the height of the vertical and span of the horizontal stabilizers determined for different turbofan aircraft like the Airbus A380 and the Boeing 747-8?

What are the maximum forces (in kilograms or Newtons) acting on both the horizontal and vertical stabilizers for aircraft like the Airbus A380 or the Boeing 747-8?


texts:
At the risk of being marked as a duplicate question, i am raising my first ever question in aviation.

I have always wondered how/why of aircrafts positioning, ever since the "lost" plane of Malaysian airline. Here are few things that are still unclear to me -

We have fairly precise GPS service available to cars/phones etc. why cant the same be availale to planes? And more importantly, why cant the planes reciprocate with their own coordinates ? Better if it can be shared in real time ? What are the challenges?

I have read some about ADS-B a little and understand that it has its limitations.  owever, when we have so many human lives at stake, why is a better solution looked into/implemented?

The limitations that have been described for ADS-B systmes is pretty serious, given that many of the aircraft today travel through horizon boundaries.

How exactly do "people" get to know of a aircraft and/or its position in order to "potentially" strike it using a missile etc? Is any of ADS-B data available publicly allowing a plane to be tracked by "anyone"? if so, why also, isnt that encrypted, and if not, why not?

My thought process is mostly around "how can someone track a plane without being part of the ATS system/network"?

What are the areas of our planet not covered by navigational satellites ?  There are references to lack of navigational satellite coverage in many areas on earth.  For that reason, I want to understand more on that topic.  For an aeroplane, flying on a given route, transmitting its position to a satellite above, what are the potential challenges?


texts: Are artificial magnetic fields used or proposed to be used to shield high altitude pilots and astronauts from charged, high energy radiation?

texts:
If not for the earth's magnetic field our atmosphere would be bombarded by high energy plasma (ionized gas) from the sun and other space sources.  At very high altitudes and orbital altitudes this protection is less and when space travel takes astronauts out of range of earth's magnetic field there is no protection.

Does the International Space Station or other craft have an artificial magnetic field to protect its astronauts?  If not are there plans for implementation?


texts: What is the usual practice in interacting with ATC at Top-of-Descent?

texts: Presuming an ordinary long-haul flight on which the plane's navigation system has selected a point as Top-of-Descent, and there are no particular issues (such as weather), when would ATC typically be contacted?  That is, would the pilots seek to obtain ATC clearance for descent in advance of reaching TOD so that they could start down at exactly that point?  Would the pilots cross TOD and then call ATC to ask for clearance?  Would there be a point when the pilots get early clearance to descend once the TOD point is reached but wait awhile to hit the TOD point?


texts: What are the effects of a rejected takeoff?

texts: When a pilot is abandoning a take-off, what are the effects on the aircraft performance? Can a pilot vacate the runway normally or is extra time on the runway needed? Is immediate assistance provided by the airport?


texts: What exactly are these frequency uses mentioned in the FAA's advisory circular on VHF use?

texts:
The FAA's document AC 90-50, (currently AC 90-50D) sets forth how the aviation communications frequencies (118.000-136.975) are allocated in the United States.  Many of the assignment designations are plain enough, and common to the understanding of pilots, but some designations are outside normal use, for example:

Aviation Support
Domestic VHF
Flight Test Stations
Flight Inspection Use

Is there a document which provides descriptions of what these designations are and what qualifies as legitimate use of those frequencies?


texts: What instruments or avionics do balloons usually have?

texts: For normal sightseeing flights in a typical hot air balloon, what instruments or avionics does the pilot usually carry? Do balloons have a minimum equipment list?


texts: What is the lump under the English Electric Lightning's fuselage?

texts:
What is the lump underneath the English Electric Lightning's fuselage?

Source: www.forwallpaper.com


texts: What are the minimum requirements to pass the FAA medical exam?

texts:
What are the requirements like height, weight, sight to pass the medical exam for getting a pilot's license ?

Are there any medical conditions that would make someone to fail it?
I know daltonism would be one of those.


texts: What is the most effective of propeller's rotation in a two-propeller engine airplane?

texts:
Consider two-propeller airplane as picture below (picture 1 (the above) and picture 2 (the below)). Which one is the most effective configuration to produce thrust power, stability, structural design, etc if still any?

Picture 1 (above): the bigger angle of attack (due to parallel to the gravitation) is meet near the fuselage, in between the two propeller's axis.
Picture 2 (below): the bigger angle of attack is outside the two propeller's axis.

Need physic analysis to answer this question.


texts: What are the speeds for absolute ceiling and coffin corner?

texts:
This picture is taken from Safety First (Airbus magazine). Could you please clarify some things:
1). Is "Absolute aerodynamic ceiling" = "Coffin corner"?
2). Have I correctly understood that there is no "Absolute Ceiling" (ROC=0) in this diagram?
And a question that doesn't relate to this particular picture. At absolute ceiling we can fly at only one speed. This is the speed which corresponds to intersection of power available and power required curves? And what is that speed at which flight at Coffin Corner is only possible?


texts: Can a "Destroyed" Helicopter be repaired and flown?

texts:
If a helicopter is reported by the NTSB as Destroyed in their Accident report, and as they make no disposal recommendation in their reports, can the aircraft be legally rebuilt by an authorized and approved FAA and Bell Repair facility and flown again?

Follow up:

The aircraft in question, after using Bell referenced repairs, carried out by a Bell Licensed Repair facility, in a Bell Certified Jig, now has its Certificate of Airworthiness and is again Supported by Bell and has a handsome price tag.


texts: What are the abilities and limits of a hexapod-based flight simulator?

texts:
So, that's a professional hexapod- a. k. a. Stewart platform-based flight simulator (image source: Wikipedia - "Stewart platform").  By moving the simulated cockpit, it simulates the movements of a plane during its maneuvers.

But the range of maneuvers it can realistically simulate is certainly limited - it can certainly simulate a straight flight, but I doubt it can give its occupants the realistic impression of a full barrel roll.

Given an existing, recent (i. e., modern and advanced) siulator for commercial aviation:

What are the actual limits on maneuvers and their parameters (i. e. turn and turn radius, banking and bank angle)?

Bonus question: How does this compare to the flight situations encountered in a typical flight?


texts: Is it possible to perform the Lomcovak manoeuvre in a C152 aerobat?

texts: Has anyone performed a Lomcovak manoeuvre in a C152 aerobat, is it even possible, or would that likely overstress the engine?


texts: How do airlines pay for aviation fuel and services at an airport they don't normally use?

texts:
On flights of a regular nature to set destination airports, I assume that there is a system is in place between airlines and airports/providers to pay invoices for fuel/services.

What do airlines do if diverted to an airport that the airline never normally serves or a freight airline doing a one-off flight to an airport? How do they pay? Does the captain carry a company credit card to pay for these one off charges?


texts: Has the number of angle of attack sensors been reduced in Boeing 737 Max, in comparison to the older models?

texts: Boeing 737 is flying since 1967. I would like to know first how many ' angle of attack sensors' does it have, and has they number been reduced for Boeing 737 Max, in comparison to the older models like 737 Next Generation or 737 Classic, for instance?


texts: What makes someone a 'Senior First Officer'?

texts:
Some airlines have a Senior First Officer rank. Apart from the title and (presumably) the pay, what makes them different from a regular First Officer?

Do they have any differing duties or responsibilities? And do they need to pass some kind of test, or is the rank just given to them after a certain amount of years service?


texts: Can the center of gravity ever fall outside the mean aerodynamic chord?

texts:
Can the aircraft center of gravity be outside the mean aerodynamic chord (i.e. %MAC being negative or more than 100%), at least theoretically?

I'm not an expert in aviation. All I've heard is the safe CG range on nearly all aircraft lies between 10 and 50% MAC.


texts:
I saw that in Jeppesen airway manual but I didn't find a definition for it. What is that?

How to establish it? Who establishes it and for what reason?


texts: How can I use electric motor data with my prop data to obtain a power available versus velocity curve?

texts:
I'm not entirely sure this is appropriate for this forum but it's worth a shot...

I have propeller data ($C_T$ , $C_P$ , J , and $\eta$) and very very limited electric brushless motor data (motor diameter, shaft diameter, Kv, voltage range, max amperage) I am trying to put together a power available curve (P vs V) but I'm not exactly sure how to use the data I have to do so.  How do I get shaft power from my engine data?  Or what can I use?


texts: What steps do I need to follow to use my PPL for income?

texts:
So I am currently taking my PPL because flying was always a passion. But, as I am sure all who do such can relate, it is an expensive license to hold on to.
None the less we go through simply for the joy of flying. But I am wondering if we can transform, somehow, or how fast could we, make this investment something we could have as a possible weekend job?
So, what would be the path to take starting from a PPL to be able to fly an airplane and also make a profit out of it?
Thank you all for your experience sharing and patience!

PS: Apologies for missing this one out, countries around Europe, though more specifically UK and Portugal :)


texts: In a Practice Forced Landing (PFL), what are Low Key and High Key and how are their locations determined?

texts: Please explain what are "low key" and "high key" in practice forced landings? Are they any particular locations with respect to the airfield? Are they the same for every aircraft? Will they change based on runway elevation?


texts: How do airplanes get stacked in a holding pattern?

texts:
This question prompted me to wonder how it works at a major airport. Let's say four airliners all are scheduled to arrive within a few minutes of each other to a major airport, perhaps from the four cardinal directions. Things are already backed up at the airport, let's say landings are (temporarily) restricted due to an emergency landing.

Can you describe how ATC might direct the four flights and what they would do themselves?