texts: Since when are ground-based starting devices no longer in common use? Are there any jetliners flying that would still require them?

texts:
Nothing is written in Wikipedia on how the engines of the De Havilland Comet or other similar airliners were started. However, it seems that aircraft of this generation could not start the engines stand-alone without the ground support, and that the Boeing 727 in 1963 was the first jetliner capable of doing this.

In one of the answers Terry describes technicians suffering desperately while attempting to start 747 with the two old ground-based devices. From this it looks like while "theoretically possible", this was a very uncommon and unexpected task for them.

Since when are ground based starting devices no longer in common use? Are there still any jetliners in service that would require them?


texts: How do I use the GNS 620 Trainer provided by Garmin?

texts:
I downloaded the Trainer for the Garmin GNS 620 here.

I installed and now have a few programs. I can open the GNS 620, the touchscreen GPS and boot it up, plan a route and so on.

There's also a program to open the G600, the PFD and MFD. However, when I open this program, it just says it can't connect to a simulator and exits.

My questions is: How can I use those trainers properly? How can I simulate the flight? How do I control the virtual plane? Do I need a simulator for this?

I would really appreciate answers, as I have no idea what to do.

Thanks!


texts: Does an increase in air temperature actually improve aircraft performance?

texts:
Mainly because of what pilots learn about density altitude and aircraft performance, any idea that an increase in temperature could improve performance seems counterintuitive. And indeed it is. Here's what got me thinking about it.

In studying for a written test I ran across a question phrased something like this:

  An aircraft flying at a constant power setting flies from a colder temperature to a warmer temperature. What happens to true airspeed and true altitude?

The correct answer turned out to be that true airspeed and true altitude both increased. I knew immediately on the altitude because I remembered reading how very cold temperatures can cause dangerous errors in altimeters, but the airspeed didn't make sense.

I still don't understand why the increased temperature lead to an increase in true airspeed. Obviously a reciprocating engine doesn't perform better in warmer air. We don't install "interwarmers." Does it really mean that warmer air can actually improve performance? Or does this need a deeper explanation?


texts: When do flights get cancelled due to fog?

texts: When flights get cancelled due to fog, what triggers the cancellation? Fog is too thick, too wide-spread, blocks the view of tall buildings or other landmarks? Or is the problem the type of air traffic? Too many helicopters or small-ish aircraft?


texts: What is the proper way to update the time enroute in an EFB system without the assistance of any GPS technology?

texts:
I remember training with paper nav logs and the student would have to update the actual ground speed based on time between two waypoints in a flight.

In an EFB, what is considered the proper way to do this per FAA standards?

Does the student need to e-mail and print the automatically-generated navigation log, and use it in a paper form with an E6-B flight computer along the route of flight?

If they are using GPS, does that suffice for ensuring they're staying updated as long as they calculated expected fuel burn at each waypoint based on GPS-indicated ground speed?

The software we use is ForeFlight, but surely this question is not limited to ForeFlight alone.


texts:
What is the best way to shut a door that has popped open in flight?

I had a door on a Cessna 172 pop open shortly after takeoff and was unable to get it closed, but I was fortunate enough to be able to quickly circle around and land. I tried reaching across with my right hand, but I was unable to push the door open enough to pull it quickly enough to latch. Is there a way to shut a door?

Source

In this accident of a Cirrus SR22 the pilot became disorientated by an open door and crashed. What procedure should be used for an open door?


texts: Can high-bypass turbofans cruise at high altitude?

texts:
They have talked for years about re-engining the B-52 with something more modern than its TF33-P-3/JT3D turbofans, which are fairly low-bypass (1.42:1 for the JT3D).

Modern engines are much higher bypass - like the GE Passport at 5.6:1, similar to the CF34 - in the same weight class and thrust as the TF33.   A larger engine like the LEAP has an even higher bypass ratio, e.g. 11:1.

Now, the B-52 has a published operating ceiling of 50,000 feet.  The 737, A320, Bombardier RJs etc. have a ceiling of 41,000.

However the KC-135s, re-engined with semi-modern CFM56 high-bypass turbofans, have a ceiling of 50,000 feet.

So I am confused. Does the bypass ratio have an impact on the practical ceiling of the aircraft?  Could the B-52 fly to current spec with engines like the GE Passport?

A side question... the TF33 claims a specific fuel consumption of 0.56 lb(lbf-h).  I can't seem to find that figure on the most recent high-bypass turbofans.  Is it inapplicable to high-bypass turbofans?  If not, is there a viable way to figure what a modern engine would do to the B-52's range?


texts: In what emergency situations would a pilot bail out of a helicopter?

texts: The Hiller UH-12 POH actually mentions “Emergency Exit in Flight” as an emergency procedure. What emergencies would make the pilot do this and why don’t other helicopter POH’s mention this?


texts: Are there attempts at fly-by-wire servo flap controlled rotor?

texts:
Reading this question and then this document about servo flap controlled rotor

I was wondering if there has been any attempt at building one fixed hub helicopter with twistable blades hosting at 75% span one electric servo motor actuating trailing edge flap, where cyclic and collective pitch adjustment is programmed in flight computer, instead of having a mechanical synchronization & actuation.

This could allow one simple rotor hub and rotor axis design, only including brushes or brushless things to transmit electrical needs to servo motors.

Mainly getting rid of this:

(source)

and using fly-by-wire? If not why?


texts: Can I descend during downwind or I can only descend when I am at base?

texts:
If I am close to the end of downwind, can I commence a descend first or I must make a turn first, e.g. leaves downwind and enter base, before I can descend?

Is there a official reference to support this?


texts: How can I find places to store/land a private airplane?

texts:
Say I'm the proud new owner of a Cessna 172.

To celebrate, I want to fly my family from Texas to Orlando Florida for a weekend visit.

Local takeoff is easy enough. I live close by, and I know the locals so I can "borrow" a runway.

However, how do I coordinate the landing in Orlando? I know commercial options are available like the Orlando International Airport, but that seems... expensive.

Even if I paid to land the Cessna (which I have no idea of the red tape involved with this), I'd still have to find somewhere to "park" to plane for my weekend trip.

However, looking at other options in the area I see several flight schools, and even some "private owned" airports with operational runways.

Which brings me to my question: if the pilot of a small aircraft wants to land in place far yonder, what's the best way to plan for this?

Is it common practice to call all the "small guys" in the area first and see if they're willing to work with your flight schedule?

If they gave you the go-ahead to land and store your aircraft in their facilities, is there any paperwork you should sign to protect your aircraft in the case of theft/vandalism?

What if the commercial airport is the only viable "runway" you see close to your target destination? What red tape is involved with landing/storing a small aircraft on commercial landing strips?


texts: Is the angle of attack equal to zero when the plane is on the ground with wings level?

texts: I read in the internet that when an airplane stands at the airport (horizontal) it has zero degree aoa. The captain must pitch up the plane during cruise to generate an amount of lift and when the airplane pitches the relative wind also changes, and this will affect the angle of attack. This is really confusing me


texts: Why does an airplane require 3 pilots on board?

texts: A car requires only 1 single driver. Why do airplanes require 3 pilots given that each pilot does not come cheap to the airline? Furthermore, a plane can go on auto-pilot while a car cannot. Could there be more room for efficiency by reducing the number of pilots needed?


texts: What is the difference between Best Rate of Climb and Maximum Rate of Climb?

texts:
Is there a difference between Best Rate of Climb and Maximum Rate of Climb?

From my research, best rate of climb trades ground distance for altitude (i.e. steeper climb, more altitude per unit time).  Since an aircraft cannot climb faster than its max rate, these appear to be two different labels for the same concept.

Am I missing some nuance between the two?


texts: In track while scan mode of radar operation what are the methods to predict next position of target?

texts: In a track while scan system (TWS) the algorithm states that the processor predicts the next position of the target and compares it with the actual position but what are the actual methods of prediction?


texts: Flying out from an uncontrolled field, should I contact approach or departure at the nearby control field?

texts: I am a new pilot who flies out of an uncontrolled field. When I depart and want to ask the controller for the nearby controlled airfield for flight following, should I contact approach or departure, or it does not matter?


texts: What does "Raven" [phonetic] means when used by ATC?

texts: What is the meaning of "Raven" [phonetic] heard in use at Reagan National Airport?  Most recently heard: The ATC will say "proceed direct raven" or "direct raven maintain" whatever altitude; or "direct raven; raven at 6,000."  I've looked in every ATC/Pilot glossary I can find, but nothing.  Have not heard at other airports, not even Dulles or BWI in the Washington metro area.  A military pilot friend thinks it is an enroute, departure, approach or holding fix, which he says would be specific to one airport.  Can anyone tell me exactly what we are hearing [an acronym?] and if this is the meaning?


texts: Do you say prefix K for airport codes in the US when talking with ATC?

texts:
I'm a new student, and I see the US airport codes on charts with the K prefix, e.g. KORD for Chicago O'Hare.

I have always seen on commercial flight booking sites, only the last three, letters such as "ORD" are displayed.

Are pilots meant to pronounce the full code or just the letters after the prefix, assuming the K prefix, when talking with ATC?


texts: Possibility commuting using GA aircraft between rural towns?

texts:
Last week I went to visit my friend out in California City and noticed they do have an airport over there, so here is my idea.
Would it be practical to fly GA aircraft between California City and Los Angeles on a commuting basis, multiple times every week if not daily? Or generally commuting using aircraft in the rural area?
I know some areas in Alaska people doing exactly just this, but is this doable everywhere?


texts: Difference between engine rev up and run-up

texts:
Explain please the difference between these jet engine terms:

rev up
run up

Obviously they are completely different procedures. The reason I ask this question is because I'm not a native speaker and have some problems differentiating these 2 things.
You don't necessarily have to go deeply into technical details about these two procedures, however it would be welcomed ;)


texts: Why both ICAO and IATA headquarters are located in Montreal?

texts: Montreal is not large city like Paris and New York, nor a important place in aviation history like Kitty Hawk(Wright brothers first flight) or Friedrichshafen (Zeppelin airship first flight). Why Montreal is being chosen as the headquarters of 2 biggest aviation organization.


texts: What is the difference between an aeroscraft and an airship?

texts: I stumbled across this site when I was searching for info about airships. They have main three products - aerocraft aeroscraft, airship and aerostat. Aerostat is clear for me somehow. But what is the key difference between aerocraft aeroscraft and airship?


texts: Why does afterburner exhaust have "pulses"?

texts: Instead of being consistently-dense, the afterburner exhaust looks "pulsed" in these pictures below.  Is this a trick of the camera, a natural result of interaction with the air, or is there some design science in the propulsion system that causes this effect?


texts: Are modern aircraft provided with analog consoles in case of a software failure?

texts:
I am curious about the redundancy they provide in modern era commercial aircraft.
Here are the questions:

If an aircraft suffers partial or complete software malfunction, do the pilots have the choice of flying the craft with help of analog consoles for critical systems(e.g. speed, altitude, heading indicators and basic flight controls). It summarizes to the point whether they provide such analog devices ?
In case of such failure, can the engines keep running so as to provide thrust, fuselage pressurization and breathable air supply to cabin?


texts: Shall We Consider Reversers in performance Calculations?

texts:
Thrust reversers are featured to help slow down the plane after touchdown.
Moving the thrust levers aft activates the translating cowl to open, closing the blocker doors. This action stops the fan airflow from going aft and redirects it through the cascade vanes, which direct the airflow forward to slow the aircraft.

My question is Shall We Consider Reversers in performance Calculations ?


texts: Can time logged in foreign aircraft be applied towards an FAA certificate or rating?

texts: Does time logged in these foreign-registered aircraft (cross country, etc) count towards US certificates or ratings? Or is it flight experience that should be excluded from an 8710?


texts:
According to FAR 91.205 (d)(6), one instrument required for IFR is:

  A clock displaying hours, minutes, and seconds with a sweep-second
  pointer or digital presentation.

Why is it necessary to time things in the cockpit, or know the time?


texts: Has there even been a case of pilot incapacitation due to food poisoning?

texts:
On commercial flights, pilots are usually required to have different meal, to reduce the chance of food poisoning affecting both pilots.

Is this just a precautionary measure, or has this actually occurred?


texts: Why does the MD-87 have strakes on its engines?

texts:
Apparently, the MD-87 has a strake on both engines:

Source: Airliners.net
If I'm not wrong, the engine strake attaches the airflow at high angles of attack on the wing. But in this case the engine is behind the wing. So what is the purpose of this little fin? Is it a strake or something else?


texts: Reason for limited engine fuselage on Sukhoi fighter aircraft?

texts:
To my amateur eye, there appears to be limited fuselage on the engines for Sukhoi fighters from Su-27 on.  That is, the fuselage follows the curvature of the engines closely and there is a definite material difference between the adjacent fuselage.

This seems to be a characteristic specifically of Sukhoi fighters or their clones.

What is the purpose of such a feature?

I realise might be a state secret as to the actual design decision and will accept such an answer but I suspect there is a straight-forward engineering reason.  And perhaps I am mistaken on my assessment.


texts: How does the turbulent boundary layer thickness affect separation?

texts: I read that for a turbulent boundary layer, a thicker boundary layer separates earlier than a thinner boundary layer? Why is that? Or is it the other way around?


texts: Does a "climb and maintain" instruction override a "climb via the SID" one?

texts:
This question pertains to the SNSHN THREE SID out of Ontario, CA (KONT).

Let's say I was originally cleared to "climb via the SNSHN departure except maintain 8,000". Then the clearance is amended after departure to "climb and maintain FL 240".

My question is, am I still required to cross NLAND at or above 14,000, as depicted in the SID?


texts: Can accelerations be used to calculate load factors?

texts: Can I use the z accelerations to calculate the load factor in that axis? Please explain how or why not.


texts: What is needed to operate a LSA aircraft at night?

texts: As a PPL holder in the USA, what do I need to have on the aircraft (or otherwise?) in order to be able to legally fly at night?  LSAs are much cheaper to operate, so it looks very tempting in order to be able to fly more hours, I'm just concerned about getting stuck out at dusk, especially in winter.


texts: What FAA license does the EASA LAPL convert to?

texts:
I have read about getting a FAA licence to 'piggyback' with a EASA PPL(A).
Is there a similar route for a EASA LAPL(A) licence.
I assume if there is then there would be the same restrictions ie Max 4 on board, No night flying or IFR flying allowed, simply VFR, which would not be a problem for me.

Basically, I am looking to take a flying holiday (vacation - let's not upset the U.S. readers) - not hour building to gain any additional licences or ratings.


texts: Would a roll cage plus a safety harness make a small GA aircraft accident more survivable?

texts:
It seems to me that race cars (like Formula 1 and NASCAR) and small GA aircraft (like a Cessna 172 or Piper Cherokee) travel at generally the same speeds, roughly between 70 and 200 mph. Yet, if an accident happens, you appear to be more likely to die in a small plane than a race car.**

I figure this may have to do with some of the safety features of race cars versus the safety features of GA aircraft. The main features being the racing harness and the roll cage.  (And also, as Freeman pointed out in a comment, the HANS device and the helmet help quite a lot as well, especially in frontal impacts.)

I know roll cages weight about 80lbs and that they aren't cheap, and I know a safety harness can be difficult to put on and people might not like using them, and I know a HANS device can be cumbersome, as also a helmet can be. But forget all of that for a moment. I'm not asking about why we don't use them from an economic/utility perspective.

What I really want to know is if putting these in a small airplane would be of any benefit to begin with. It's true that they are massively helpful in racing vehicles, but I wonder if the forces racing vehicles face during a crash are markedly different than what you would find in your typical GA crash (e.g., perhaps aircraft accidents happen at less predictable angles, or involve more torsion, etc.). And if perhaps those differences in forces make the use of a roll cage and a safety harness kind of pointless in a small plane because they can't actually help in that kind of accident.

So, would all of these racing safety devices actually make a GA crash more survivable, or does the nature of GA accidents make their use less effective than they are in a race car?

** Try as I might, I couldn't find hard stats on "deaths per accident" in either area.  So this is mostly an impression I've gained from reading a lot of NTSB reports and watching a lot of racing. The fact may be debatable, but shouldn't detract from the main question.


texts: Why doesn't Ketchikan, AK have a control tower?

texts:
Why doesn't Ketchikan International Airport (PAKT) in Alaska have a control tower?  The special flight rules applicable to the area (14 CFR 93 Subpart M) seem to make it clear that traffic management is an issue, focusing mainly on being in contact with the Ketchikan flight service station when it is in operation.
The now uncommon situation of an On-Airport Flight Service Station as noted in AIM 4-1-3 would seem to be in force here, but in Ketchikan, it appears that under the SFAR, seen in Ketchican FSS Information, participation is mandatory.
With mandatory participation, what separates Ketchikan from an airport which would normally be served with a control tower?  Does it not quite qualify based on traffic?


texts: Are there any airports with multi-level taxiways?

texts:
There are many airports where roads (and pedestrian walkways) are routed underneath taxiways, runways, etc. But are there any airports where airplane taxiways go under/over each other?
I can't imagine there would be (for many logistical and sanity reasons), but in this world of unusual design and construction paradigms, I've learned to not say that something has never been done.  This could either be airports that are currently in use, or ones where they were used at one time, but are no longer active.


texts:
Since more and more airlines are dropping the 747 for the 777 or equivalent due to fuel efficiency, a theoretical question came to mind.

What do you think is preventing Boeing from creating a 747 twinjet (two engines instead of 4).

I know there are probably design/engineering issues associated with such a conversion, but I reckon that if it was done it may increase sales to go up against the A380? Not sure the math as well, but perhaps the engine from the 777 could be used or configured for higher thrust?


texts:
I'm a beginner in airfoil design. I just came across swept-back wings. There is a point that I couldn't understand that theory.
Why is the only perpendicular component of the airflow to the wing(component parallel to chord line) affects the shockwave formation? Why doesn't the total airflow vector(spanwise +chorwise vector component) contribute towards shockwave?
Why wouldn't the shockwave form with the total airflow vector in the swept wing?
I have attached the image to show my point better


texts:
Many light general aviation aircraft-- and perhaps many other aircraft as well-- are designed with some of amount of downthrust in the engine mounting, relative to the centerline of the fuselage.  Presumably the wing incidence angle is chosen to streamline the fuselage in some particular flight regime.  So why is any downthrust designed into the engine mount?  Exactly what is the designer trying to optimize, by including downthrust in the design?  In what undesirable way would the aircraft's flight characteristics be different if the downthrust were not there?
For example, is the intention that adding power (without re-trimming the elevator) should not make the aircraft climb?  Or that adding power should not cause a change in trim airspeed?  Or that adding power should not cause a change in trim angle-of-attack?  Would there be a "wrong-way" change in trim airspeed when power was added, if the downthrust were not present?  If so, why?
Note that one reason for some reduction in trim airspeed when power is added to climb but angle-of-attack is held constant, is given in this related answer.  (See the tables-- and note that a similar reduction in trim airspeed would also occur when power was reduced to descend.)  The present question anticipates that this effect may be minor enough not to be the main reason for including downthrust in the design of any particular airplane.
This question is aimed primarily at aircraft with nose-mounted propellers and conventional tailed configuration, so please be sure to address this configuration, but feel free to discuss other configurations as well.


texts: I was going through FCOM of A320 and came to know that FCOM chapters are called as ATAs. So first of all what is its full- form and secondly why do we call the chapters ATAs ?


texts: What calculations are needed for counter-weight balancing on a propeller?

texts:
I am designing a small-scale propeller and i have managed to design on optimized geometry for the blade. However the blade pitch angle adjusts according to different flow speeds so i need to mount counterweight to maintain the balance of the blades. What i need to consider for the calculations?
Let's say i know already the counterweight shape, mass, and mounting place.


texts: Is it possible to predict how busy an airport will be in a given time? (are there existing services that to this?)

texts:
I want to know if it's possible to predict how busy an airport will be at a given day or part of day.

I know there are services that provide the scheduled flights in an airport

Is there also an API that allows programmatically accessing this data (preferably for free)
How far in advance are the flights scheduled and the data published?

The distribution between 'regular' passengers and 'connecting' passengers is also important (a passenger during a connection has a much lower effect) - it the data of how many passengers in a flight taking a connection available? (even long term statistics)


texts: Is any device installed on airplane to measure wind speed relative to the ground, and its direction?

texts: A device or tool which can measure actual wind speed to the ground rather than to the airplane. Also a device which detect the wind direction to the plane. The device I meant is something like this pitot. But unfortunately this pitot is measures the airplane relative to the air around it, not the ground.


texts: What would happen if a pilot tried to land with a tailwind?

texts: What if a pilot was forced to land in a tailwind? Would this be possible and what is the maximum tailwind an aircraft can handle?


texts: How long has the term "situational awareness" been used in aviation?

texts:
I was puzzled to read (Wikipedia article on situational awareness) that:

  The term can be traced to World War I, where it was recognized as a crucial skill for crews in military aircraft.

but in the next paragraph:

  There is evidence that the term Situational Awareness was first employed at the Douglas Aircraft Company during Human Factors Engineering research while developing vertical and horizontal situation displays and evaluating digital-control placement for the next generation of commercial aircraft.

and then the next:

  Situation awareness appears in the technical literature as early as 1983

I imagine that the concept found work in understanding piloting very early on; what is the history of the term in aviation?


texts: What is the wire running from the CG to the tail?

texts: I was looking at airplanes a while back and noticed that there is sometimes a wire running from about the CG near the wind to about halfway up the tail.  I see this more on 737s but I have also seen it on C130s.  What is this wire?  To hold up the tail?  I have seen: What is this wire going from mid-fuselage to the tail on this 737? but I am more interested in all of the other planes that have it too.  Are there planes that actually use guy-wires for support or are all of the wires I see antennas?


texts: What benefit is provided by an MCA that is not already provided by an MEA?

texts:
I continue to read definitions of MEA as the minimum altitude across the entire segment to ensure obstacle clearance and navigation/comm signal reception. It also states that this is the lowest altitude across the entire segment.

The way I interpret this is that as I fly towards the segment I must be at or above the MEA when I enter the segment to ensure that minimum across the entire segment. Given this why is there a need for MCA (minimum crossing altitude)? The MCA definition requires that minimum altitude at the segment boundary. Why would the MEA not be sufficient?


texts: I have seen a couple videos of fighter jets and commercial planes with HUD systems and was wondering how do the heads up displays work?


texts: How can I scale down a propeller for wind tunnel testing?

texts: I want to scale down my propeller for a wind tunnel testing. But I am unable to find any literature on it.  Please give suggestions.


texts: Does pilot-controlled lighting work if you are interrupted by another voice transmission?

texts: This question is in the context of pilot-activated runway lighting, which involves clicking the microphone e.g. 7 times to turn on the lights at night. I was wondering what happens when you are clicking the radio button, which typically takes several seconds, and suddenly someone else starts transmitting on the same frequency while you are still clicking? Does that mean your attempt has failed, since the other person's transmission is often continuous? To what extent is the receiver on the ground able to discern between the two signals? Does it depend on our relative proximity to the airfield? Or is this nothing I should worry about?


texts: What is it like to volunteer with Civil Air Patrol (CAP) as a pilot?

texts:
I saw various people talking about volunteering with CAP. I’m about to sit my test for my PPL, and am wondering whether there are opportunities to volunteer for search and rescue, or more generally, am interested to hear what is involved.

(I’m in the San Francisco Bay area, if anyone has specific local content as well.)


texts: What was the range of a low-frequency radio range station?

texts:
The low-frequency radio range is a historic navigation aid that was in use from the 20's to the 70's.

I find it quite interesting. Using AM frequencies, what was the range of a high power LFR station?

A video on YouTube suggests it was even used to cross the Atlantic with stations in Greenland.

Source, LFR across the U.S., 1933.

Secondary question, based on the approach plate below, the red rectangle area shows what I believe is the AM frequency. What about the other four VHF(?) frequencies?

The frequencies seem to correspond to the ranges used by today's FSS/CTAF and military UHF. Searching CAA historic regulations wasn't helpful.

Image source


texts: In ARINC 429 where are the bits indicating the hex value of Equipment ID?

texts:
I'm a newbie in ARINC-429 standard; the following might be a very simple issue for you.
In ARINC 429 the LABEL field  is covered by the bits 1 through 8; which bits are covering the Equipment ID?
For istance: Equipment ID 002 hex (Flight Management Computer) would require 12 bits to be represented. Where are located these bits in the ARINC word, so that the receiver could read the it?
Thanks for your assistance.


texts: Why does airflow separate from the wing during stall?

texts:
What causes the airflow separation from the airplane wing, that triggers a stall?

To be more precise, what is the detailed explanation of the physics for why flow separation occurs at certain speeds & angles of attack?


texts: Does anyone have a diagram of the HC-130J wing dimensions and fuel tank locations?

texts: Looking for a drawing of the HC-130J that includes fuel tank locations and wing dimension (more than just wingspan)


texts: How do landing gear retracting into the wing affect performance when deployed?

texts:
On many aircraft with low wing, landing gear (either wheel, leg, or both) retracts into the wing. Thus, when deployed, a significant part of the lower surface of the wing is not as clean as when the landing gear is retracted. It must affect aerodynamics by adding drag, but may also affect lift as this modify airflow along the wing.

For the aircrafts whose landing gear or landing gear leg retracts underwing:

How does the landing gear affect aerodynamics when deployed and when deploying?
Is it different for aircraft whose landing gear do not retract into the wing?
Does this modify performance critical when taking off or landing such as stall speed, optimal climb speed?


texts: Can you file an open-ended IFR flight plan?

texts:
Say you are doing an instrument training flight with a CFII and you are practicing IFR navigation. You will be taking off and returning to the same airport, but you are not certain exactly where your CFII might have you go. For instance, your CFII wants to see how you handle deviations in flight. Ths is just an example as I'm sure there are other reasons one would need to be IFR without a specific routing or destination. How would you file such a flight plan? Can you file an IFR flight plan without a specific routing?

Another reason I can think of would be a test or acceptance flight that needs to be conducted in class A airspace. You would have to be on an IFR plan to fly there, but your ultimate destination would be right back where you came from. You might not be able to indicate specific waypoints, etc., instead you would be requesting block altitudes, etc. if you need room to perform maneuvers.


texts: What's a TRA and how does it differ from a TFR?

texts:
This is from a recent email from the FAA Safety Team:

  The FAA will soon begin limited use of a Temporary Restricted Area
  (TRA) in certain areas when the types of operation(s) to be conducted
  there require a TRA. The flight rules that apply to a TRA are the same
  as a Restricted Area (RA). The best FAA resources to view any TRAs
  upcoming or active are the FAA Special Use Airspace (SUA) website and
  the Notices to Airmen Publication (NTAP).

Usually when the FAA wants to temporarily restrict access to airspace it puts up a TFR and it isn't clear from the wording of the email what a TRA is, why the FAA would create one rather than a TFR, and what the operational differences are between a TRA and TFR.

What is a TRA and how does it differ from a TFR?


texts: Why are some taxiways named with two characters?

texts: The picture above is a diagram of the Taoyuan Airport, Taipei, and as you can see in the diagram, some taxiways are named with two characters like “NC, NP, WC.” My question is: Is there any good reason, if any, why some taxiways are named with two characters when, clearly, there are other single letters still available?


texts: can the wreckages of a hot air balloon and a hang glider be salvaged for a working hang glider?

texts:
I'm currently working through my collection of Spike and Suzy albums, and in the album I'm currently reading, one of the main characters crashes with a hot air balloon near the wreckage of a hang glider without sail cloth. The main character, who is usually characterized as a somewhat smart man with skill in engineering, tore a large section from the balloon cloth, tied it to the hang glider wreckage and managed to make a functional hang glider that could even make a reasonable ascent in the Alps, near the Mont Blanc and catch up with his friends who were in other hot air balloons.

The hang glider looked like this (I couldn't find a bigger image, sorry):

How would this type of makeshift hang glider work IRL? even though hang gliders and hot air balloons are made from the same kind of fabric (ripstop nylon), wouldn't the holes between the frame and the cloth totally ruin the thing?


texts: What is the difference between company routes and pilot routes?

texts: I was trying to find out what are the different route types(flight management system) and found out there is one company route and one pilot route . Are there more different route types ?.What is the difference between the company route and pilot route


texts: Does a previous AFSP approval get invalidated when making a new training request?

texts:
If I've already been approved, and started training in one school and then create a training request to switch to another school, does the previous approval expire?

In other words, can I be simultaneously approved on two different schools?

I'm considering transferring temporarily to continue flying in a different region, but would like to have the option to return to my original school without yet another training request...


texts: How could "aggressor" pilots fly foreign aircraft without speaking the language?

texts:
Context

I watched a couple documentaries recently and found one where they were mentioning the training of American forces against Mi-24 that were captured and brought back to the US to test fly them. Shortly afterward General Chuck Yeager tweeted a quote from General Boyd saying

  Because of Yeager, we now know more about the MiG-15 than the Russians do.

after he flew one in 1953 that was captured during the Korean War.

Research

This piqued my curiosity because as far as I know Russian aircraft have:

Different units for instruments (metric system with km/h, meters etc.)
Different approach to instruments (as explained in this question)
Obviously, everything written in Cyrillic with alerts in Russian

I checked the page on Constant Peg program in the US to train aggressors and them flying foreign aircraft (like MiG 17, 21 and 23) as well as other aircraft. While I understand that this specific program is still classified, there are other occurrences of aircraft flown by "non-Russian speakers" or at least non-Natives.

While it is totally possible that General Chuck Yeager is fluent in Russian, I have some doubts about flying an aircraft where everything is written in another language from the fuel dump to the auto-pilot settings, and be able to operate it easily (on top of that without a manual).

Question

Now this led me to this question, how do you fly an aircraft without speaking the language and how do you read the instruments and their functions ?

I very much doubt that they just put sticky notes over all instrument panels with the label of instruments (but I could be wrong, who knows).


texts: Should "mayday" be preferred over "SOS" in an emergency?

texts:
I was asked about the difference today. The only difference I know is that mayday doesn't appear in the exams ( like the SOS parts of the book, you get the joke? :) ). I also found the difference in the origin, but:

  What is used in aviation? Both are equivalent or there is actually a difference and the one should be preferred over the other?


texts: Is there a surface of a commercial jet exposed to air flow at speed near Mach 1?

texts:
With commercial aircraft flying slightly above Mach 0.8, is there any surface exposed to speed of air significantly larger, e.g. near Mach 1? ignoring:

The engine components,
The boundary layer as clarified by Trebia Project.

Edit: Reading useful information provided in comments and answers, I realize the key notion is "critical Mach number", and the question boils down to:

  Are commercial jets flying at critical Mach number speed or higher?

since the critical Mach number speed is -- by definition -- the one at which some airfoil portion experiments a supersonic airflow. See also:

How does exceeding the critical Mach number of an aircraft affect its operation?


texts:
does anybody know how one can calculate the position, shape and size of an aircraft with a canard?

So the main goal of a canard configuration: increase lift + increase agility/maneuverability

So at least I can calculate the centre of pressure of the whole aircraft, which has to be behind the CoG to guarantee static stability in pitch.

But still, I have a range in x-direction , where I can place the canard. What do I have to define or know in order to place my canard?

  Lift: I can design my main wing and its lift A_W_wing. In horizontal flight A=W=A_Wing +A_Canard ; So I could now design my A_Canard (shape, size).

But what about the maneuverability? What do I need to now?

So for my opinion: for a curve to fly with a specific rotating rate, my control surfaces (tail + canard) need to create a specific moment. Since Moment = Force * Arm  I could make calculate the needed Arms/ positon ?

Thank you for any tips on literature or calculations


texts: Do modern airplane controls provide force feedback of external forces on the control surfaces?

texts:
As I was sitting inside the cockpit of an old AN-26 at the aviation museum, long grounded and no longer flightworthy, sudden gusts of wind outside would sometimes move the control surfaces and make the yokes move around all on their own, spooking visitors with creepy thuds and groans of the hull and acting all creepy on the dark windy day. It seems in the days of old, with mechanical controls, it wasn't just the pilot acting on the control surfaces through the rudder - when attacked by winds, they would feed the external forces back to the yoke through the same system - likely both providing the pilot with important knowledge, and causing trouble by wringing the yoke in his hands.

I wonder how that looks like nowadays in modern planes, where the control is electronic, hydraulic, and a feedback like this would need to be specifically, additionally implemented, as an extra complication of the system instead of being in its inherent nature. Well, is it? Do the yokes of, say, modern airliners push harder on the pilot's hands when entering a turbulence or such?


texts: Could a larger consumer drone "take down" a passenger plane?

texts:
As a frequent flier, I'm just concerned about my own safety.

Could a larger consumer drone, such as DJI Inspire, (intentionally) "take down" a passenger plane?

When I say take down I mean causing the plane to crash or emergency land.

I guess just a contact would not do too much harm but could it do some when flying in the engine?

Considering that larger drones can easily carry bigger cameras, it could also carry a 1kg or similar of explosives.

Are drones the biggest threat to commercial airlines as anyone can buy them and the chance of finding the pilot is very small?


texts: What class is the airspace at KGCN when the tower is closed?

texts:
I was wondering if someone could help me figure out how the airspace around the Grand Canyon National Park Airport (KGCN) works. The chart supplement here says:

  AIRSPACE: CLASS D svc 1 Jun thru 30 Sep 1300–0300Z, 1 Oct thru 31 May 1400–0200Z other times CLASS G.

... but the Grand Canyon VFR chart here says:

  See NOTAMs/Directory for Class D/E (sfc) eff hrs

The VFR sectional just shows a class D ring around the airport with a class E surface area extension to the southwest:

When the tower is not occupied, how is the airspace around KGCN arranged?


texts: What can be approach of balancing canard glider model?

texts:
There are a lot of instructions out there about balancing classic wing configuration glider models. The center of gravity should be approximately 25% to 30% from the front edge of the wing, which is easy to control. The next step is flight tests and adjustment by adding or removing weight or moving the wing forward or backward. Using this approach I constructed several gliders with stable horizontal flight.

But what can be approach for balancing canard configuration glider model? Is it the only recommendation for the canard wing to produce more pitch applied to the center of gravity then the main wing produces, is it possible to verify this somehow before testing flights?


texts: Why don't airlines have in-flight video recordings like buses do?

texts: That way we could study plane crashes more closely, or terrorist hijackings, or resolve passenger disputes. Even buses in Ecuador have video cameras.(WARNING: shocking video)


texts: Since gliders don't have engines, is it possible for them to go around? Are there any extra features on a glider to try to prevent that situation from happening?


texts: I've flown a Piper that has a button labeled CWS on the yoke, right next to the "Push-To-Talk" button.  I never got a chance to push it though.  What does it do?


texts: How can I compute the minimum possible bank angle for a turn with a given radius?

texts:
I know that I can find an upper bound for the bank angle for a plane, if I know the maximum sustained load factor of that plane because the roll angle and the load factor $n_z$ in a turn are directly related:
$$tan (\varphi) = \sqrt{n_z^2 - 1} \;\; \text{or} \;\; \varphi = arctan\left(\sqrt{n_z^2 - 1}\right)$$
And also I known that the bank angle would not be more than 30° for civilian and 75° and more for military aircraft.

But my question is :

How can one get the minimum possible bank angle an airplane can use to perform a turn with a given radius before reaching the stall speed?

Also I want to know if the stall speed is known, can we use the formula :

$$ W = V/R $$

to calculate the angular rate of turn (of course considering the level turn)?


texts: Can the FAA allow a foreign training center to add a type rating to an FAA license?

texts:
I have an ICAO license and an FAA one with the same type rating on both. I have done the initial training through the FAA in the US, but was able to validate the sim, training center and the DPE to get the type on my other ICAO license as well.

Now I wish to do the same, reversed - get an initial for a different type on my ICAO license and have the FAA validate it so I will have it on my FAA license as well.

Is that possible?


texts: What are the reasons why we do not have VTOL commercial airliners?

texts:
I understand that there are noise issues, and that there may be an economic case dependent on stage length, but other than that I'm not quite sure why they haven't happened. Is there something technical I'm missing?

Exhaust gas re-ingestion doesn't seem to be that great an issue, it looks like you just install fences to make sure that exhaust can't get into the inlets.


texts: What protocol should be followed after accidentally entering restricted airspace with a UAV?

texts:
This is related to my earlier question.

Delhi has a lot of areas with restricted airspace and no fly zones. Assuming we are able to get the necessary licenses and permissions to fly, what should we do if we accidentally enter no fly zones while in controlled flight?

The altitude will be less than 400 meters.

Once (and if) we are clear of the no fly zone, where should we report the incident?

This is a hypothetical question. I do not intend to break any laws knowingly.


texts: Why is the centre of pressure for a real wing with low aspect ratio more forward than that in two-dimensional flow?

texts: Why is the centre of pressure of a finite wing ahead of the quarter chord point predicted by 2D flow over the airfoil? Also what is a "LOW" aspect ratio in terms of numbers. The literature has terms like "very low A.R" "low A.R" "Moderate A.R" and "High A.R", but the actual ratios in terms of numbers are not given.


texts: What is the best or most popular way to reduce wing tip vortices on an ultralight operating at 600-800k Re?

texts:
What is the best or most popular way to reduce wing tip vortices on an ultralight triplane, operating at 600-800k Re with fibreglass wings ,10 ft wingspan, gap of 2 chord, chord of 2 ft, 0 stagger?

Upturned wing
Endplates
Horner tips
Other?


texts: Does the FAA always require a neuropsychological assessment battery for applicants with a history of ADD?

texts:
I'm in the middle of a medical struggle with the FAA. I'm applying for a 3rd class medical certificate but was hit with a deferral letter due to a childhood ADD diagnosis. Currently the FAA is only asking for:

"A personal statement regarding my ADD history and medication use."
"All treatment records and evaluation from the physician who prescribed the ADD medications in the past."

My question is this - does the FAA require a neuropsychological battery test for all applicants with an ADD history, or is their requesting a testing battery contingent upon what I say in my personal statement and the included treatment records / evaluations?
My treatment records and physician evaluation conclude that I no longer have ADD symptoms. In addition, I've flown intensively with a United Airlines check airman (pilot responsible for evaluating the flight ability of other United Airline pilots) and he has written a letter stating he's seen no evidence of ADD and, in his professional opinion, I am qualified to pilot an airplane.
Do you think, after submitting this documents in my favor, I will be able to avoid undergoing the testing battery?


texts: What is the procedure to replace carpets in airliners?

texts: Are all the seats removed, as well as trim and baseboard, before the carpet is replaced? If so, how is reinstalling the seats laid out; do they feel for the boltholes? Are the seats bolted on top of the carpet or directly to the floor?


texts: How do I keep the neighboring Remote Control Airfield from flying over my property?

texts:
I live in the North Georgia Mountains. The neighboring remote control airfield was put in front of my house where my mountain view is. I have no issue with them flying over their lease, just not over my property and in front of my view. I have approached them to stop, but they refuse.
Do they have the right or can I have them served for trespassing?


texts: Is the war pilot obligated to fly the same plane daily or must he change the plane according to every required mission?

texts: Can the pilot change his plane, or can he fly in any plane, obediently, to the same plane as the one trained on it?


texts: Which clearances are issued by ATC without the pilot requesting them?

texts:
Some clearances are only provided after specifically requesting them, such as the departure, engine-start, taxi or oceanic crossing clearance. Line-up and Take-off clearances are issued once the pilot relays to be ready for it (this could be viewed as "actively requesting" the clearances.

As I have learned after this question, sometimes descent clearances are issued by ATC without the pilot asking for it. Which other clearances are issued "automatically"? Specifically, I'm asking about the approach clearance and the landing clearance.


texts: Does terminal control have final say on which runways the towers should use?

texts:
In areas where there are many airports close to each other under one Class B airspace...

Do nearby airport towers coordinate together with runways to use as to reduce the workload on the terminal control?
Does the terminal control tell them which runways to use?
Is it free-for-all for the towers, and the terminal control just deals with it?

Note that if they all choose the same direction more or less, all takeoffs and landings will be parallel, but airport layout dependent, a non-wind facing runway might be favorable for a certain airport.


texts: Do anti-collision lights in aircraft lose intensity over time?

texts: Do anti-collision lights installed in aircraft lose their intensity over time and need to be replaced every few hundred hours of operation?


texts:
Trying to learn about aviation, and looking through all the displays in the cockpit, and also the Garmin G1000,  I am not sure where I see the distance to the runway touchdown point, or the start of the runway. Sure, I see the ILS glidescope indicator, telling me I am too high/low, but where is the runway?

Ergo, my question is this: If flying in heavy fog, dark night, let's say visibility down to 2 meters! how does the pilot know where to land? Some indication of the distance would be great.

Thanks a lot, much appreciated.


texts:
If a hypothetical aircraft, which is a tailless straight flying-wing with no fuselage, has the following characteristics:

moderate forward sweep
an aspect ratio = 9
a dihedral angle of 3 degrees
a slight tapering of 5 degrees on each edge
wing twist (10 degrees of total incidence difference between centreline and wing tip)
positively cambered airfoil at centreline, slightly less at the root, minimally positive camber at the inboard section, symmetrical outboard section, negative camber from there towards the wing tips
thickness 10% at the tips, 15% at the root and 20% at the centerline
a low wing loading, i.e. 50 kg/m2
slightly forward CG

And if the required stability in yaw (proverse yaw) is considered to be ensured through sufficient wing twist and symmetrical airfoil/negative camber at the tips,
what kind of airfoil characteristics - or even better - what specific airfoil examples (or at least, a specific airfoil category) would provide both low induced drag and ample lift ability at low speeds of 50KT, but still have low resistance at higher speeds i.e. at 200 KT?
Specifically, how much camber and reflex camber change (in ratio to symmetrical) should be sought for each of the different segments of the wing centreline, root, outboard section and wingtip?
Or, would it be sufficient if the whole planform has an identitical airfoil shape (scaled for chord length due to taper)?
What would be the Centre of Pressure positions (in chord percentage) of such a wing at slow flight or in high-speed cruise?
——
I know it may be a fairly wide question with a myriad of possible answers but I would be grateful to see some examples, so I can have some notion on what the camber/reflex camber for these wing characteristics should be, and to better understand via examples.
Thanks


texts: Since when had fighter jet designer stopped caring about Whitcomb's Area Rule?

texts: According to this source, designers of military fighter jets seemed to have stopped centering their design on Whitcomb's Area Rule for quite a while. Yet even the twin series fighters struggle to break the sound barrier without afterburner in a combat loadout. Then why have the designers stopped caring about transonic drag reduction? Or is it because they never intend to let their jets come near Mach 1, just a little bit below it or use the afterburner and shoot past it? Does this mean newer supercruising fighters, if they intend to fly all the way up to their Mach 1.5-ish cruise speed on dry power, should still care about shaping according to the Area Rule?


texts: What is the relationship between the EASA and JAA?

texts:
I have heard of two different European aviation authorities: EASA and JAA (or JAAT).

What is the difference in their functions?  This would include things such as:

Whether they are somehow part of the same organization, but are referred
to separately (such as the FAA and NTSB both being US government agencies).
One being the parent organization of the other.
Whether they are separated by which countries they oversee within Europe.
Whether they issue separate licenses/certificates.
Whether one is an older version of the other similar to the CAA being the predecessor to the FAA.


texts: Why was the P-51 Mustang not adopted by the U.S. Navy?

texts:
I've heard from many WWII aviation hobbyists and WWII vets that the P-51 was essentially the pinnacle of U.S. piston-engine fighter design; it was fast, maneuverable, long-range, well-armed, allowed superb pilot visibility, etc etc.

So, why did the Navy never adopt it? It seems there were flight tests of the P-51D as a carrier fighter, modified with a tailhook for wire capture landings, but the Navy never pulled the trigger (so to speak). What were the primary reasons behind this decision?


texts: Can I use parachute fabric to cover an aircraft fuselage and wings?

texts:
...

Are there disadvantages to using parachute fabric to cover an experimental aircraft? So far I observed the following:

I believe I put this fabric in an open place for a year
I found no cracks after a year, approximately
When I tried to set the fabric on fire after a year it didn't catch on fire. It shrunk, but it didn't burn.
I didn't feel any weaknesses or holes in the fabric
I also checked the tension of fabric
In a weight test it up to 10 kg baggage

Now I'm trusting this imported parachute fabric.

I tested three pieces: one original, a second doped in poly varnish, and a third with a paste of mud/soil/sand mixed with poly varnish. The third is best and resists fire best.

Can I use it cover an aircraft?


texts: How long it takes for Pilots to prepare for landing?

texts:
I'm wondering how many minutes prior to Final approach do pilots decide what type of approach they will carry on with at the arrival airport like (VISUAL/CATI,II,IIIA,IIIB) ?
Like how many minutes before they get the latest METAR or weather reports and decide accordingly how to carry on with their final landing and how long all this preparation takes before the actual touchdown ?


texts: Are children safe when seated in lap during a flight?

texts:
We would never consider putting an infant or toddler into a car without a carseat, but we don't hesitate to do exactly this when getting onto a large airplane.

If you aren't aware of the concept of a lap child, this is a child, typically under 2 years of age, who can board an airplane without an assigned seat and must be held by a parent/guardian for the duration of the flight (including the takeoff and landing). The only safety consideration is that the lap child must be seated in a row with adequate O2 masks in case of depressurization (some rows have more masks than seats).

I have always considered this to be an unsafe practice, but have never had data to back that up. It seems to me that holding on to a 20 lbs child when subject to strong turbulence or unexpected maneuvering would be difficult. While not common, adults are occasionally severely injured in these events but I've never noted a lap child being hurt.

Does anyone know of instances where a lap child was injured during a flight? I'm not interested in instances where everyone is hurt but rather instances that having been secured in a car seat would reasonably have prevented the injury.


texts: These "FICON" NOTAM's contractions aren't in the FAA contraction list. What do they mean?

texts:
These NOTAMs for KSGF state "Snow" when the icon on the left is hovered over with a mouse.  The contraction "FICON" does  not appear in the Notam Contractions list.

It is currently the middle of June in nearby Oklahoma, and it is hot here, so a NOTAM related to snow doesn't make any sense.

What are these NOTAMs telling us?


texts: Could a FOSS autopilot system ever pass FAA regulations?

texts: Think something like ardupilot but for manned aircraft.


texts: How are the 747-400 rudder pedals and tillers connected to the nose wheel?

texts:
The Boeing 747-400 Before Taxi Procedure says (emphasis mine):

[...]
Flight controls .............................................. Check C
[...]
Hold the nose wheel tiller during rudder check to prevent undesired nose wheel movement.
Move the rudder pedals to full travel in both directions and verify:

freedom of movement
that the rudder pedals return to center
correct flight control movement on the EICAS display

The FCOM (14.20.3 Landing Gear - System Description) further says:

Nose Wheel and Body Gear Steering
Nose wheel and body gear steering is powered by hydraulic system 1.
Primary low speed steering control is provided by a nose wheel steering tiller for each pilot. Limited steering control is available through the rudder pedals. The tillers can turn the nose wheels up to 70 degrees in either direction. A pointer on the tiller assembly shows the tiller position relative to the neutral settings. The rudder pedals can be used to turn the nose wheels up to 7 degrees in either direction. Tiller inputs override rudder pedal inputs.

I wonder how the rudder pedals and the tillers are connected. How can the tiller override the pedal input? I assume the tillers would move when the pedals are used, but do the pedals also move when the tiller is rotated?


texts: How much efficiency gain can be attributed to aircraft handling?

texts:
Since the beginning of commercial jets, constructors thrived to make planes more fuel efficient. I assume most gains since then come from cleaner aerodynamic design, weight savings, and engine design.

However, these are not the only factors to take into account.
For example, we have also became better at predicting meteo, or transmitting live information about airstreams so that planes can spend more time in the most favorable zones.
Traffic control can also improve fuel efficiency by optimizing the landings of planes or reducing taxi/idle time.

How much of the gain in efficiency can be attributed to this factors ?

Another way to phrase it would be: How much more fuel efficient would it be to fly an old plane with modern avionics today?


texts: What to do if expediting your ascent or descent is impossible/unsafe?

texts: As a pilot of a small single engine plane, what do we do if ATC instructs us to expedite our climb/descent and doing so would be impossible or unsafe (i.e. we're already at the maximum safe rate of climb/descent)?


texts: Why does an Exhaust Gas Temperature (EGT) gauge require a power source?

texts: Why does the EGT gauge on jet engines require bus power if thermoelectric voltages generated by thermocouples are sufficient to move the needles?


texts: How can I find out how much a passenger window of a Boeing 737 costs?

texts: Where do I have to look to find out how much a passenger window of a Boeing 737 costs?


texts: Is it possible to reject a landing after the thrust reversers have been deployed?

texts: Since thrust reversers take time to deploy and stow are you committed to the landing once you engage them?


texts: Exceeding VLO and by how much is too much?

texts: Piper Seminole (PA-44-180) VLO (max gear retraction speed) is 109 KIAS. I've heard that manufacturer published limitations are significantly lower than actual structural and system limitations. What are the potential repercussions of retracting gear at 10, 20, 30 KIAS over VLO?


texts:
Why don't rudders stall at 30 deg deflection, as they don't have downwash to reduce local AOA like flaps and horizontal tails do?

or do they?

I understand flaps and horizontal tails don't stall at 30 deg deflection as the downwash from the wing reduces the local Angle of Attack, so flaps and horizontal tails aren't seeing an angle of attack
 of 30 deg even though they are deflected by 30 deg.

However, there is no "vertical downwash" from the wing to help the rudder.  Why don't rudders stall at 30 deg deflection when most classic NACA airfoils stall at about 15-20 deg?


texts: Can the cracks found on the A380 wings tear the wing apart?

texts:
Given all the press given to the cracks found on some A380 a few years ago, I am concerned about the safety of the current fleet of A380 owned by major airlines, although the planes are fairly new (less than 10 years), and are, I hope, well maintained.

Could their be today a catastrophe resulting from these cracks, especially between the 2-year revision period?


texts: Is engine damage due to a fan blade failure irreparable?

texts:
I have a question related to this question and this video. The question says that sometimes a fan blade failure can occur.

My question now is, if a fan blade separates or a malfunction occurs, is the engine still repairable?
I think the damage to the engine's structure would be quite high?
According to the video a fan blade malfunction occurred on start-up, how could a malfunction appear on start-up?


texts:
I'm particularly thinking about larger aircraft with more than two sets of main landing gear.

It's pretty obvious you would not want them to rotate while landing and take-off, but while taxiing around or being tugged, the drag caused by fixed axis wheels would be significant on tighter corners, and would leave rubber on the tarmac.
As such one would presumably want the wheels to track the turn.
That effect would be even worse for something like the Antonov 225... which I have no idea how they turn on the ground...

If they do somehow pivot, is there some sort of locking mechanism that is employed prior to take-off and landing.
Note this has nothing to do with crabbing for landing, but for ground maneuvers.


texts: Is everything OK with engine placement depicted in Flight Simulator poster?

texts:
Does the Airbus A320neo depicted in Microsoft Flight Simulator 2020 box cover photo has the right engine in all the wrong place?
Here is  the snapshot:

Is it only me, who clearly sees that it is way too close to plane's body and actually attached to it?
If I am correct then would that mean that someone has artificially modified the original picture, when preparing promotional photo, and made that modifications completely wrong?


texts: Can a pilot amend a flight plan in-flight?

texts:
Which information pilot can change in-flight?
For example:

Altitude. Ask to climb higher?
V to Z. VFR rules to IFR (VFR to IFR)?


texts: Could airliners use a steam or electric powered catapult for take-off?

texts:
This would have the obvious benefits:

Less runway needed to take-off
Fuel savings
Faster turn around times for airlines

Could this be implemented in busy airports?


texts: Why is it necessary to fly in visual conditions to certain unmanned airstrips?

texts: I have come across certain unmanned airstrips where only VFR flight is allowed not IFR? I wonder what can be the possible reasons for that?


texts: What is the accuracy of distance and position calculation?

texts:
I would like to learn about the flight distance calculation and positional accuracy requirement in aviation.

In practice, great circle distance is calculated between two airports but earth is more accurately represented with an ellipsoid and in this context, global positioning is based on WGS84 ellipsoid.

Is it useful to calculate geodesic (shortest path on the ellipsoid) rather than great circle on the sphere for more accurate estimation of the distance?

When thinking that flight routes are 3D, are 3D distances calculated in flight planning? In addition, are these 3D distances calculated with elliposidal cartesian (ECEF) coordinates (X,Y,Z) regarding ellipsoid height (height(MSL)+geoid height (undulation))?.

Does it make sense to calculate the flight distance in "meter" against "km" precision? If it is in nautical mile, what is the precision? e.g. 2394 nm or 2394.xx nm?

My another question is how accurate the 3D position of an aircraft is determined? What is the future perspective in this context together with satellite-based navigation and augmentation systems?


texts: What is propeller / engine sync and how does it work?

texts:
In some models of multi-engine airplanes there is a switch labelled something similar to "prop sync" or "engine sync".

My questions are:

What is engine synchronization?
How is it achieved?
Why is it important to use?
What happens if you don't use it?


texts: What are the types of these 3 single-engine aircraft and one Multi engine aircraft?

texts:
Here are several photos of older aircraft I'd like help in naming. Year, Model, & Manufacturer.
Thanks so much.
Ron


texts: What are the other clearance and instructions that must be read back?

texts:
The following items must always be read back:

ATC route clearances;
clearances and instructions to enter, land on, take off from, hold short of, cross or backtrack on any runway; and
runway-in-use, altimeter settings, SSR codes, level instructions, heading and speed instructions, and, whether issued by the controller or contained in Automatic Terminal Information Service (ATIS) broadcasts, transition levels.

In the definition it goes on like this: Other clearances or instructions, including conditional clearances, must be read back. What do I have to obtain from these "other clearances or instructions" I think it is the really broad term?


texts: Since when did European regulations require the ability to suppress alerts?

texts:
Thanks to @Gerry's comment on a recent answer of mine, the 2011 ruling on the FAA's amended 14 CFR § 25.1322 mentions:

Adopting this rule also harmonizes flightcrew alerting standards between the FAA and the European Aviation Safety Agency (EASA).

That's related to suppressing alerts, which Airbus aircraft have had since at least the mid-80s – the EMER CANC button for example on the A320 for suppressing spurious alerts.
This made me wonder since when EASA (or its predecessor) have had the similar rule that was adopted? (I couldn't find my way around the historic regs of EASA.)


texts: 24 hour access at general aviation airport

texts:
I was doing a night flight with my kids and one had to go to the bathroom.  I was happy that when I landing at an airport (KVLA) and they had a door code so I could get to the bathroom.  Is there a list anywhere of small GA airports that you can get access to the bathrooms 24 hours a day?
If not, what is the best way to make one?


texts:
What is the exact criteria for wind speed to be considered "CALM".
Different countries might have different values and i do not mind getting answers from those. But an answer from an ICAO annex would be prefered.


texts: From which aircraft does this vintage altimeter come from?

texts:
I bought this vintage U.S. Navy Kollsman altimeter at a market in Bangkok, Thailand.

Unfortunately, I don't have any info other than what you see in the photos.

It's a Kollsman altimter and the model or serial number is KO-67ICLU-035 Type/6433 MB-I

There is another serial number(?) on the scale which reads MS28044LI, and below ALT it reads 50,000FT.

Here's another clue: This sticker says the altimeter was serviced in the PNCLA (Pensacola) 89771 NAVAL AIR REWORK FACILITY in the 3rd fiscal quarter of 1981.

Another sticker says it was tested at the Naval Air Rework Facility Pensacola (NARF) and found to be free of radioactivity, also in 1981.

Finally, S/N-71 is embossed on the backside of the altimeter.

So what type of aircraft could this instrument have been part of?


texts: Would winglets add fuel efficiency on a Concorde?

texts: Would adding winglets to a Concorde have a had a positive impact on its performance and fuel efficiency in retrospect, considering the technology was not widespread or developed at the time these machines were flying and would that at all have reduced/increased its sonic boom?


texts: Why would a C150's tachometer fluctuate?

texts: Why does a Cessna 150 aircraft tachometer fluctuate between a specific rpm between 800 and 1100 rpm? The idle rpm of the aircraft is 800 rpm.


texts: During takeoff, why throttle forward then raise hand from throttle to push a button, instead of pushing button then throttling?

texts:
Preface: The comments assert the video to have been horizontally flipped, probably because (I am divining) the original belonged to someone else (user 'Jb380' if I remember)?

At 4 mins 3 secs of this video, the captain (who appears in the video on the right, but per the preface above, should be on the left) pushes forward the throttle, but from which he then removes his hand to use this same hand to push a button that changes an instrument display,

from showing the tail view (camera) of the aircraft (to assist with taxiing???),
to the primary flight display.

Afterward he replaces this hand back atop the throttle.

Why doesn't he instead push the button before deciding to takeoff and set takeoff thrust: this is safer than the above? For example, if abortion is decided exactly when nobody's hand is handling the throttle, then previous seconds needed to stop would be wasted?


texts: Has a pilot ever been disciplined for taking a guest for a flight in a single-seat fighter aircraft?

texts:
I recall reading of a spitfire pilot who was suspended for taking a member of the WAAF up for a jaunt to impress her. She supposedly sat in the pilot's lap throughout the short flight and they were caught when they landed and a member of the ground crew noticed her alighting. I specifically remember the author referred to her as "a uniformed lovely" in his recounting.
I've spent some time googling around and rummaging in my library but to no avail. Can anyone identify this specific incident (ideally the exact account) and/or have there been other incidents that are similar?


texts: What criteria make an airport suitable for a technical stop for a large airliner?

texts: Assume you have a large airliner such as a 747, and you're taking off from a place, such as Ovda, where you can't load enough fuel to make it to your destination without stopping somewhere along the way.  From all the airports along the route to your destination, what criteria are used to determine what a suitable "somewhere" to stop at for fuel is, assuming that runway size and fuel availability have already been filtered for?


texts: Is the lift produced by a wing with a 10° flap equal to the lift created by a wing with 10° AOA but with no flap?

texts: After reading this article I would like to know if the lift produced by a wing with a 10° flap is equal to the lift created by a wing with 10° AOA but with no flap?


texts: Why does using carburetor heat increase fuel consumption?

texts: As written above, why does using carburetor heat increase fuel consumption? Because I found such information in a few SOPs for piston airplanes and I do not understand why does it happen


texts: What is the difference between AIM, AIP and AIS in the US?

texts: I know that in the US there exist documents which are published by the FAA such as the Aeronautical Information Manual (AIM) and the Aeronautical Information Publication (AIP). What is the difference of each one? What is their relationship with the Aeronautical Information Service (AIS)?


texts:
I would like to really understand why when talking about jets we care about thrust but when talking about propeller aircraft we care about power.
(THRUST)="Just a force"
(POWER)= work/time = force x velocity
I know that even though propeller aircraft are called "power producers" and not "thrust producers" as jets, any aircraft needs Thrust because that's what overcomes Drag. The difference is that a prop aircraft uses the Power of the engine to turn the prop while a turbine engine produces Thrust by itself.
I also know that total drag curve comes from induced drag (decreases with airspeed) and parasitic drag (increases with airspeed), so that is exactly what thrust needs to overcome. The total drag you get at a given airspeed is equivalent to the thrust you need to stay level. That makes a lot of sense.
I have no problem with jet theory when thinking about that and the Thrust required / Thrust available curves.
Why is it different for prop aircraft? Why is the power curve important? I mean, aerodynamically. Because I've seen that total drag curve is also the same as Power Required Curve and I don't understand why.
My first thought is:
Engine power is important because that is what the prop will use to rotate and generate Thrust. (Propeller efficiency is directly related with HP and other prop aerodynamic factors). However, even with the most powerful engine, if prop efficiency is poor because of the other factors, we won't get too much thrust and that's the only thing that matters. And one more time, thrust is what makes any aircraft fly forward, so total drag is thrust required, not power.
Vx speed is found where the greatest difference between thrust available and thrust required is. Greater excess thrust equals greater angle of climb. (Got it!) that's very logical for me.
But: Vy is where the greatest difference between Power Available and Power Required is found.
What?! Why?! How can the power the engine produces relate with airplane's aerodynamic?? It has nothing to do with that. Vy is best rate of climb, the airspeed at which the airplane will get faster to an altitude. I think that the reason should be related with a thrust/drag ratio.
On the other hand, I know that the Power Curve results from multiplying each thrust value times each airspeed value of the thrust curve. That's the fact, just let me explain why it doesn't make any sense to me...
Power=force x velocity, and we can apply that in different ways. If we were talking about electricity we could say Power is measured in Watts, and Watts= Voltage x Current. Because we are talking about prop aircraft, we should use a power unit like HP (for reciprocating engines). HP= Torque X RPM.
Multiplying the Thrust Curves to get Power Curves would mean that Power= Thrust x Airspeed
What kind of power are we getting when multiplying thrust times the airspeed at which the airplane is flying?
Wouldn't that be something like "Aircraft power = thrust x airpeed" or in other words "the amount of power needed to stop that airplane"? Nothing to do with the engine (which is really the reason why a prop airplane is called "power producer")
I'm very confused, even tired of not understanding the exact reasons behind this after reading what should be sufficient. I think I know what power and thrust are, but I just can't understand the way they relate, and to be more specific, how does excess power affect the aircraft flying in real life, aerodynamically. Why to talk about Power instead of Thrust in any case, jets or props. (It's clear there's a good reason not to, and that's what I want to finally understand). Maybe more realistic examples or comparisons instead of graphs and curves would help.
(But those are not a problem either in case you want to try.)
I'm a student pilot and I hope I was clear enough with my doubts and explanations.
(Also with English since Spanish is my native language)


texts: Are there any problems opening a helipad close to an airport?

texts:
I am looking at the possibility of installing a helipad at my house which is within 1.5 miles of a Class D airport. The location is not in the approach to any of the runways, however.

I am not a rotorcraft guy, so I am wondering if having a helipad this close to an airport will cause any issues?

(note that the whole area is Class B airspace, so it will always require a clearance to take off)


texts: At what altitude, on land, do our ears pop?

texts: So, it's obvious that our ears pop when we go into deep water or fly high in a plane but at what altitude on land do our ears pop? I need to know for a book.


texts: How do I follow an ILS glideslope on the ADI in Falcon BMS?

texts:
I'm currently flying the ILS landing mission in Falcon BMS, I'm practicing landing using the instruments (head down) and although I'm mostly OK with the LOC, I struggle to maintain a 2.5 degree glideslope.

In the training doc for Falcon BMS there is the following information:

  ADI gives an angular reference to the position of the glideslope. Each
  dot on the left side of the ADI represents an angle of 2.5°

But I don't know how to achieve the above. I watched some YouTube videos but I didn't see anyone aiming for those dots on the ADI (yet they managed to land perfectly).

I don't want to chase the glide path bar on the ADI, so how do I hold a proper glideslope using the instruments?


texts: What is "one flat movement" of a screw on the fuel control unit?

texts:
I'm looking to do a N1 low idle speed adjustment oa King Air B350 with the PT6A-60A engine. There is a note saying that one flat movement of the low idle speed screw in the FCU increases N1 by 3.5%

What is "one flat movement" in this context?


texts: How do you avoid power of 10 or order of magnitude errors when using an E6B calculator?

texts:
I am currently working through Gleim's instructions for using their E6B calculator.
It says: "The numbers on the inner and outer scales represent multiple sof 10 of the values shown." And "EXAMPLE: The number "20" on either scale me represent 0.2, 2.0, 20, 200, or 2,000".
I've been working through the examples, and a recurring problem is getting the right value to multiply by 10, but not knowing what power of 10 to multiply it by. (To put it in math terms: right mantissa, wrong exponent).
What is the process or rules to make sure you get the right answer every time? Obviously, getting a flight calculation wrong by an order of magnitude is not a problem you want to have!


texts: Why don't aircraft fly direct via oceanic airspace from UK to Iceland?

texts:
Whenever I watch the routes of aircraft flying between BIKF (Keflavik, Iceland) and e.g. EGLL (Heathrow, UK), they make a small turn in between to avoid oceanic airspace. See for example this flight route:

(Source: Screenshot of https://www.flightradar24.com/data/flights/ba894#236858ea)

The turn is made at the point where Shanwick Oceanic, Reykjavik FIR and UK airspace border each other. A direct routing would have a segment of around 220NM in Shanwick Oceanic airspace.

What's the reason, these flights don't go through Oceanic airspace? I observed that it's operator independent (ICE, BAW, EZY all fly this dented route) and it doesn't correlate with aircraft capabilities (ICE flies the same airctaft through Gander Oceanic on the way to North America all the time). So why is this routing?


texts: Why do some aircraft have symmetrical tip airfoils while others do not?

texts:
On some aircraft, the tip airfoil is symmetrical, while others carry their root foil all the way through the tip. It would seem an aerodynamic disadvantage to have a non-symmetric airfoil at the tip since it is not making much (any?) lift.

It doesn't seem to be simply for manufacturing purposes since it is on planes with tapered wings as well as straight wings.

Why is it incorporated into wing design?


texts:
I have edited this to one question and thank you for all the feedback .

I am trying to understand if there are any theoretical improvements in range when applying electric propulsion to large commercial craft such as the A380, or if the theory favours smaller commercial turbine powered craft.

A good answer for a Cessna seems to be the specific capacity of the battery = range in nautical miles. However the weight of the fuel in a Cessna is under 10% of its MTOW, whereas an A380 tops 40%.
The second good answer asserts that you would design a new aircraft, you don't convert an existing one that has been optimised for chemical combustion at the point of propulsion. The proof here is provided by the Sun Flyer.
The third theory is that doesn't matter how big or small the craft is, it's a ratio of battery weight to MTOW.

Whether we decide to convert an aircraft or design a new one, suppose we had to make an all electric commercial aircraft with the greatest possible range, would you start big, such as with an A380 or start with the smallest aircraft and why?

Some A380 facts to use are here: https://web.archive.org/web/20161012152549/http://www.airbus.com/fileadmin/media_gallery/files/tech_data/jetFamily/media_object_file_A380_specifications.pdf
Maximum landing weight= 386 tonnes
Empty weight=282 tonnes
Typical payload=66 tonnes

Thanks for the careful thought on the replies already.


texts: What is the difference between a cold-stream thrust reverser and a conventional one? It seems that all engines emit hot air, due to the combustion process.


texts: What is the use of this object in the cockpit of a Bombardier Dash 8 Q400?


texts: What are these strips on and below the tail of this HAL Tejas?


texts: What is the general process for flying a private aircraft to another country?

texts: Let's say I want to fly a private airplane to another country. How does one arrange such a flight? Of course this might vary between states, but in general do you need a special permit to fly in with a particular airplane, other than a permit to enter the country? Do you schedule a landing with the airport of destination?


texts: What is the difference in VTOL technology between British Aerospace Harrier II and F-35B?

texts:
F-35B safer and looks more stable in terms of VTOL capability.

What is the basic difference between Harrier II and F-35B's VTOL technology?


texts: Can anyone explain me the ILS Approach Chart of my Airport?

texts:
I'm from Lucknow, India (VILK) and recently I experienced my very first CAT IIIB  ILS landing at my homebase. Ever since I'm more curious to know about this technology and how it works.
I was able to get the charts of various approaches type at my base but I was interested in the ILS CATII/IIIB type but I don't understand a single word mentioned in the chart.
My flight took 4 holding patterns at 11000 feet just like how its drawn on the chart and then we flew towards east and descended to 7000 feet on our initial approach and then turned south and finally west to runway 27 at 3000 to 2500 feet and continued at 2350 feet for sometime and then descended to land.
The arrow over airport looks exactly how we took made four holding patterns before landing exactly like its drawn in the chart but I don't understand if what I'm making of it is actually what it is or not.


texts: What is the difference between regulatory and nonregulatory airspace?

texts:
The first paragraph of the FAA PHAK Chapter 14 - Airspace says:

  The two categories of airspace are: regulatory and
  nonregulatory. Within these two categories there are four
  types: controlled, uncontrolled, special use, and other
  airspace.

It never says anything further about regulatory and nonregulatory. So what do these terms mean and what are their differences?


texts: Do aviation intercoms have a standardized compatibility with radio stacks?

texts:
I have been seeking an intercom unit for a Cessna 172N that has four seats but only two headset jacks, and I would like my rear passengers to be able to communicate without yelling.

Aviation intercoms have external radio transmit switches, but the airplane also has its own built-in radio transmit system.  How does the transmit function trigger in this type of system?  Do they send a certain audio signal frequency or tone to the COM stack that tells it to transmit?

Are most intercoms universally compatible with all com stacks if they use the same plug types?


texts: How can you explicate the efficiency of a turbofan engine with Carnot's theorem?

texts:
From Carnot's theorem, we know that efficiency is

$$ \eta = 1-\dfrac{T_c}{T_h}$$

where $T_c$ is the temperature of the cold reservoir and $T_h$ the temperature of the hot reservoir. But what do we have to consider for both?

Is $T_c$ the temperature of the air coming into the compressor from the fan or the temperature of air coming into the combustion chamber after being compressed and heated by the compressor?

Is $T_h$ the temperature of the gases in the combustion chamber (1500C°) or at the exhaust nozzle?


texts: Is corrected astigmatism disqualifying for an EASA Class 1 medical?

texts: I realize there are similar questions on the site already, but not one specifically dealt with my problem. I reside and plan to work in Europe so I looked up the EASA regulations, but I couldn't really make sense of them. My question is: I have astigmatism, which is corrected by my glasses. I am also shortsighted, which is also corrected. Does this disqualify me for a Class 1 license?


texts: What are the physical/aerodynamic implications of designing a prop guard for multirotors?

texts:
A number of drones these days like the one shown in the picture below have  fully protected multi-rotor propeller guard system . These are lightweight, aerodynamic housing that keeps these spinning knife-blades away from people's fingers, trees etc.

So,what are the  physical/aerodynamic implications of designing a prop guard for a multirotor drone whose specs are as follows:

All Up Weight with battery: 1050g
Frame weight empty (no electronics, motors, or battery): 400g
Flight time with 3s 2200mah lipo: 8 minutes
Propeller size : 10"
Skeletal Plastic Structure

Source: Safe Flight Copters


texts: Why are engines angled toward the fuselage?

texts:
Source: twitter.com

I saw a picture of a 777 from overhead and I was wondering why the engines point "in" to the fuselage, rather than being parallel to the fuselage.


texts:
ASFC is an acronym frequently seen in official European publications, e.g. used by the French AIS:

Also in some ICAO ones, e.g in Annex 4 (Aeronautical Charts) to the Chicago Convention:

  The airspace is shown only from the surface to the higher of the
  following two levels: 1500 m/above mean sea level (AMSL) — 600 m/above
  surface (ASFC).

What is ASFC compared to AGL? Is ASFC also used over water?


texts: Are there any characteristics of a hypoxic flight?

texts:
Any patterns that investigators look for? For example, what happens when the engine flames out? is it guaranteed to enter a high speed dive? And would this affect certain parts of the aircraft, causing them
to separate under torsion and not compression?


texts: Why does elevator still raise and lower the nose when the aircraft is steeply banked?

texts:
In a steep turn, the aircraft is basically sideways. However, when executing a steep turn, one still raises and lowers the nose of the aircraft by using the elevator.

Intuitively, it seems to be that in an extreme bank, the elevator and rudder have essentially changed roles, since they have been rotated with respect to their normal orientation. It seems to me that in a steep turn, pulling back on the yoke should tighten the turn. But this seems to not be the case in practice, since getting the nose up in a steep turn still involved just pulling back on the yoke and/or trim.

Why is this the case?


texts: What are technical and aerodynamical limitations to blown wings main propulsion?

texts: Why wouldn't some blown flap or blown wing device (suppressing propeller or fan or jet exhaust from aircraft design) produce sufficient thrust needed for takeoff and cruise flight, opposed to "only" providing stol capabilities at low speed?


texts: Why does the U-2 Dragon Lady not have swept wings?

texts:
Swept wings increase the critical mach number for aircraft with otherwise identical wings (Source 1). The U-2 Dragon Lady is limited in altitude by its critical mach number, as it needs more speed in order to go higher (Source 2), but going faster would put it into its "coffin corner" (Source 3). However, looking at the following photo of a modern U-2 from Lockheed's website, the wings seem to have little to no significant sweep. The top speed (presumably what is used during the highest-altitude cruising) is only Mach 0.67 (Source 4), while modern aircraft like the Boeing 737 (which do have swept wings) often cruise at speeds between Mach 0.75 and 0.8 (Source 5).

Why does the U-2 not have swept wings?

I know that wing sweep was first developed in Germany during WWII; had the technology not taken hold in the USA by the time the U2 was developed in the 1950s? Or is there a deeper technical reason I'm missing?


texts: Do the blades of the rear disk have different geometry to the blades of the front disk on a contra-rotating assembly?

texts: If my understanding is correct, the air flow is accelerated by the front propeller toward the rear propeller in a contra-rotating prop assembly. Therefore, the rear disk would be receiving air at different pressure and velocity than the front disk. Does this have an effect on the efficiency of the rear disk, and if so, do the rear blades have different geometry to the front blades?


texts: Why would an airliner make a 90° course change?

texts:
Why would this airliner be doing a 90° course change at cruising altitude? I saw this while waiting for a traffic light to change.

9 Jan 2020 1:42 pm (18:42 UTC) at Virginia Beach, VA, coordinates:
36°46'38.070"N 76°05'18.03"W, my heading: 237 deg.

And from Flightradar24, flying at 37,000 feet:


texts:
Since planes traverse the Earth, and a country may deem another country's airline unsafe, yet that unsafe airline is deemed safe in its country, what is the hierarchy of the aviation regulatory bodies from the highest global level down to a state or even a town.

One example of how it moves top-down would be great.


texts: In aircraft where the thrust reversers are not locked out when airborne, is it permissible to go around after reverser deployment?

texts:
In general, a go-around, in a jetliner, must either be performed before thrust reverser deployment, or not at all.

This is because attempting a go-around after reverser deployment may result in loss of control of the aircraft.
Loss of control is a possibility because one or more of the reversers could fail to stow during the attempted go-around, potentially resulting in an asymmetric-thrust situation beyond what most jetliners are designed to handle.
This is because the reversers take several seconds to fully stow once deployed, and the aircraft could easily lift off before this happens, in which case any not-yet-stowed reverser buckets or clamdoors will be blown back to their fully-deployed positions by the aerodynamic forces on said piece(s) of reverser hardware.
Lifting off is relevant because, when the aircraft lifts off, the reverser actuators are automatically locked out and depressurised.1
The reversers are locked out when airborne to minimise the risk of an uncommanded in-flight reverser deployment, which, for aircraft not certified for in-flight thrust reversal, is generally bad.

However, some aircraft are capable of, and certified for, the safe use of reverse thrust in flight (typically to steepen descents by using reverse thrust as an airbrake [DC-8, Trident, Concorde, C-5, C-17], or to shorten the landing roll by deploying the reversers while still airborne rather than having to wait until after touchdown [Trident 1C, Il-62, Tu-154]).

To allow this inflight use of reverse thrust, the reversers on these aircraft are not locked out when airborne.
As such, the reverser actuators remain pressurised even after the aircraft lifts off.
Consequently, even if the aircraft lifted off before all reversers had fully stowed, the reversers would simply continue to stow.
As a result, lifting off with one or more reversers still in transit would not produce a significant risk of a severe asymmetric-thrust situation.
Even if, for some reason, a reverser did fail to stow, resulting in thrust asymmetry, aircraft certified for inflight reversing are required to remain controllable even with full forward thrust on one side and full reverse thrust on the other, at least for long enough to shut down the reversed engine.
This would appear, for aircraft certified for inflight reverser use, to essentially eliminate the danger of loss of control (absent other serious failures) in the event of a go-around after thrust-reverser deployment.

This would be especially important for aircraft like the Tu-154, Il-62, and Trident 1C, which routinely deploy their reversers before touchdown; if going around after reverser deployment was prohibited for such aircraft, this would seem to completely preclude very-low-altitude go-arounds with these types.
Are aircraft certified for in-flight thrust reversal (and, thus, not equipped with an in-flight reverser lockout mechanism) allowed to go around even after the thrust reversers have been deployed?

1: There is generally an override switch in the cockpit that can be used to restore pressure to the reverser actuators even when airborne (its main use is to force the reversers to remain stowed if one or more should come unlocked in flight, or to restow then in the event of an uncommanded in-flight deployment), but locating and actuating this switch would take precious seconds which might not be available in the event of an asymmetric reverser deployment at low altitude in an aircraft not certified for the inflight use of reverse thrust (especially as, during the time spent with their actuators depressurised, the deployed reverser(s) would be blowing back to the fully-deployed position, taking them further and further from the stowed position).


texts:
VNO, the airspeed where the green and yellow arcs meet on the airspeed indicator, is the "maximum structural cruising speed" (FAR 1.2). An airplane should only be flown above VNO in calm air. Comparing this to VA, the speed below which the airplane will stall before reaching its load limit, what protection does VNO provide? Turbulence that mimics a full deflection of a control surface would likely qualify as extreme, but what's the middle ground?

VA varies by airplane weight. Does VNO vary by weight, and is the calculation the same?


texts: Under what conditions are passengers required to take precautionary measures during refueling?

texts:
I was on a recent flight with a fuel emergency, during which the passengers were required to take precautionary measures. Under what circumstances are the precautionary measures mentioned below required?

The plane was diverted to a small regional airport apparently unequipped to service the Airbus we were flying in. Though the fuel truck had arrived at the plane and cones had been placed around the aircraft, we waited quite some time for the fire brigade to arrive before the fuel could be pumped. During this time and during the refueling operation, all the doors were opened (in the rain) and the passengers were required to be in our seats with no electronic equipment. Additionally, seatbelts were required to be unbelted.

The fuel emergency occurred while we were circled the Atlantic for 45 minutes waiting for the weather to clear up at Miami International Airport. When the alternate airport shut down as well (Fort Lauderdale International Airport) we were diverted to a small airport in West Palm Beach. From what I was told by a crew member after we had landed, we did not have enough fuel reserve to safely make it to Orlando.

Myself and other pasengers were under the impression that the in-the-seats-with-no-belts restriction is standard for refueling with passengers on board, but in the comments of another question I discovered that this is not the case. What are some likely reasons that these precautions were taken?

The incident occurred on 2014-05-15 on Iberia 6123 leaving Madrid at 11:50 with a scheduled arrival at Miami at 15:20. I'm pretty sure the plane was an A330 but it might have been an A320.


texts: What should I know before getting the KAMRA laser eye surgery procedure as a pilot?

texts: I was recently looking into the KAMRA procedure to fix my reading problem. Then I came across some posts that discourage it as it causes one to see halos in night so particularly bad for pilots. I was wondering if anyone else here has done that that what was his or her experience about it? What are the regulations on this as well?


texts: How to compute actuator torque requirement for Variable pitch mechanism??

texts:
Suggest me any reference to compute the torque requirement for actuator/motor to control the pitch angle of propeller (Variable Pitch Propeller).

Thanks in advance

Arun Ravindran


texts: Who owns B- registration? China or Taiwan?

texts:
Aircraft registration is unique to each aircraft. Each one begins with country code follow by numbers or characters. However wikipedia says that Taiwan and China both use prefix B. So who actually own the right to use prefix B? If two of them do not co-ordinate the use of prefix them there can be two planes of same registration in the sky. So how things work out here.
https://en.wikipedia.org/wiki/Aircraft_registration
https://en.wikipedia.org/wiki/List_of_aircraft_registration_prefixes


texts: What are the advantages of a forward-swept wing over a rearward-swept wing?

texts:
What are the advantages of a forward-swept wing vs. a rearward swept one?

Image credit: NASA

Image credit: Paul Maritz / Wikimedia