texts: What is the smiley face sensor at the stern of the F-4 Phantom?

texts:
The F-4 Phantom has an interesting collection of sensors at the extreme rear of the empennage. What are these sensors for? My daughter calls them them smiley sensors but I suspect that is not the proper technical term. Her guesses as to their real purpose:

Detect other airplanes.
Detect smiles.

Which one is it?


texts: Why is there a white line on Russian fighter jets' instrument panel?

texts:
In several Russian fighter jets (e.g., MiG-29, Su-27) there is a white line on the stick that matches with another one on the instrument panel. Is there any reason for this?

Cockpit of a mig29

Cockpit of a Su27

A former flight instructor told me that it was to help pilots recover from a spin: when the two lines match, the stick is in the proper position to stop the spin. Is it true or is there any other reason?


texts: Why do I get an overspeed warning at 250kts below 10,000ft in Microsoft Flight Simulator?

texts: I'm flying the Cessna CJ4. I get overspeed warnings at 250kts when below 10,000ft, and the speed indicator has red lines at 300kts. Are these warnings triggered because it'll damage the plane to go that fast, or because it's illegal to go that fast that low? What's the distinction between 250kts and 300kts?


texts: Safety regulations for take off spectators around airports?

texts:
In a Greek island, an A320 blasted a child ten meters away, during take off. It was with his family outside the airport (Greek src).

I wonder what are the regulations, if any, for how much people are allowed to approach the airport (I intended to say runway, but some people might not be able to identify it).

I don't expect from a common person to be aware of the dangers that occur at these situations. The airport should protect them, that's why I ask, if there are any regulations that define the min. allowed distance of people outside the airport?

If yes, it would make sense for the airport to have it's fence at that distant, not any closer.


texts: what reference of airfoil is used to define lift and drag?

texts:
On aerofoil section, the force of lift acts perpendicular to, and the force drags acts parallel to the :

A: chord line
B: flight path
C: aerofoil section upper surface
D: longitudinal axis


texts: What are these holes in my Cessna 172, just in front of the elevator?

texts: Been wondering about these for a while. Student pilot working on my PPL. When preflighting my Cessna 172 the other day, I noticed these holes just in front of the elevator. What are they for? The image shows the crease between the elevator (white) and the horizontal stabilizer (red) on the left side of the fuselage.


texts: How are both squawk and altitude transmited when operating a Transponder in Mode C?

texts:
I know that in Mode $3$ (which includes Mode A and Mode C) the aircraft transmits $12$ information pulses. That corresponds to $2^{12}=4096$ squawk combinations in Mode A which are sent to ATC to identify the aircraft. In Mode C, all $4096$ combinations are used to send the pressure altitude of an aircraft to the ATC.
Since there are $12$ usable information pulses, when operating in Mode C, there is no way to transmit the squawk code, which in my mind raises an obvious question: What if I suddenly squawk $7700$ due to an in-flight emergency? Or $7600$, radio failure? If I continue to operate in Mode C, it seems that there is no way that ATC would know that I am in any kind of trouble. How is this issue resolved and is my understanding correct?


texts: How is an on ground lightning strike test conducted?

texts:
Whenever a design company is obtaining an STC for an aircraft (Supplemental Design Certificate) for an electrical installation, one of the required tests to obtain the STC is a lightning strike test. The test is needed to show that the electronics installed can withstand a lightning strike without degrading their performance or inducing degradations into other systems.

We can't position the aircraft on ground waiting for a lightning bolt to hit like 'Doc' in 'Back to the Future', so how do design companies, or engine manufacturers, etc. simulate a lightning strike and draw conclusive results that the system with withstand actual lightning?


texts: What happens without trimming a statically stable aircraft?

texts: if I have a statically stable aircraft, it will always return to its neutral position. What happens now if I do not trim my aircraft? Will it move/osicallate around its neutral position and be statically stable but dynamically neutral?


texts: Why did the DC-3 have a much higher cruise speed than the HP.42, despite their similar weight and power?

texts:
A review of the classic DC-3 and the Handley Page HP.42 yielded a surprisingly close match in empty and max gross take off weight at around 18,000 and 28,000 lbs for the HP.42 and 16,000 lbs and 25,000 for the DC-3.  The HP.42 cruised at 87 knots on around 4x500 hp, and the DC-3 at 180 knots on 2x1200 hp.  The HP.42 was a lower aspect biplane, the DC-3 a graceful mono plane, the epitome of aviation advances for that era but...

Questions:  How much of the DC-3's speed increase was the result of improved engine/prop efficiency?  How much from the DC-3's speed increase came from its beautiful Prandtl inspired wing?  How much from retracting its gear?  How much closer would the HP be with those improvements, while remaining a biplane (perhaps with improved struts)?

I do not expect an exact answer, I am more interested to see how the numbers were crunched and a short explanation why.  Thanks.


texts: Why don't helicopters prefer shorter rotors with more blades?

texts:
My understanding of helicopters is that, despite theoretically increasing efficiency, longer blades are worse in practice than short ones in every respect (except, perhaps, cost):

Longer blades are more prone to vibration and resonance dynamics, if for no reason other than that their rigidity is reduced by length, holding all else constant.
Longer blades provide less operating clearance.
Longer blades not only stall before shorter blades (retreating), but also hit the Critical Mach number at lower air speeds (advancing).
Fewer blades require higher rotational speeds for a given "rotor disk" area, which is inefficient from not only an aerodynamics perspective but also, presumably, a transmission-and-control perspective.

But all helicopters have few blades of significant length.  So: What are the advantages of longer blades, or disadvantages of shorter blades, that lead to the rotor designs in common use?

I would imagine that in the limit it would be optimal to run something more like a ducted turbine segment, where the swept area is virtually covered in blade surface (i.e., maximizing the number of blades over the swept disc).

Noting that in practice blade size seems somewhat proportional to the body size of the aircraft, I'll deduce that in practice the bulk of the downforce needs to be generated some minimal distance away from the aircraft's body, though with some attention to the body's vertical aerodynamic aspect it seems like that could be reduced.  I guess tilt-rotors could support this hypothesis since their rotors are positioned at a distance from the body and they use smaller rotors, although it seems like they still use blades as large as possible given the wing size and body configuration.


texts: Are intersection takeoffs less common in the USA than in other countries?

texts:
On a recent trip through Australia I did a number of intra-oz flights.  In at least three of the cases we performed intersection takeoffs, a couple at MEL/YMML and one at BNE/YBBN.  I have at least a thousand domestic flights within the USA, and although I wouldn't bet my life on it, I can't remember ever doing an intersection takeoff there.

The MEL/BNE runways are quite long - even with the intersection takeoff the available runway was over 8,000 feet in each case.

Am I wrong that this is super rare in the USA?  Are there airports where intersection takeoffs are commonly used, and maybe I just never fly through those?  The advantages are obvious, it saves taxi time and fuel, and a 737-800 on a 75 minute stage can't be anywhere near gross weight anyway.  In the USA, airports like HOU/MDW have runways that are shorter than our takeoff roll, which strongly suggests there's no outright safety issue... and these airports handle hundreds of 737-800s a day identical to the QF/VA ones I was on here.  What other things am I missing here?  Are the aussies just more time/fuel conscious than us yanks?  ;-)


texts: Is it common to change the type of engine during major overhauls?

texts: Is it common to change out the type of engine during major overhauls of old aircraft?  For example, replacing a 285 hp engine with a 310 hp.  Would this invalidate the performance specifications found in the aircraft's pilots operating manual?


texts: What is needed to go from a student pilot license to a private pilot license?

texts: I will be 16 in a few weeks and I really want to get flying so I am currently thinking that I should get a Student Pilots license and then get a Private Pilot License next summer when I am 17 but I was wondering what is required to advance from an SPL to a PPL? Is it significantly more economically wise to just wait to get a PPL?


texts: What happens when an aircraft breaks the sound barrier? Why can't it break the sound barrier near the ground?


texts: What is the fan pressure ratio in a turbofan?

texts: What is it and how does it affect efficiency and thrust?


texts: Why is the ratio maximum range speed/maximum endurance speed the same for any airplane?

texts:
It seems counter-intuitive that the ratio of speeds for maximum range and maximum endurance is always the same, $3^{0.25} = 1.316...$ for any heavier-than-air aircraft, regardless of its mass, size or form. It's hard to believe that such ratio may be identical for an ultralight autogyro and for the F-35 fighter, but so it seems to be...

Why is it so?


texts: How often should an engine be run, to stay mechanically sound?

texts:
It's winter time and many light aircraft are sitting idle. This can be detrimental to an engine's health.

What is a good rule of thumb for how often a piston engine should be exercised, and for how long?

If the aircraft cannot be flown, what is an acceptable alternative?


texts: Can a pilot use glasses to meet the FAA required 20/20 vision?

texts: When the FAA said that pilots require 20/20 vision, does that mean that you have to achieve 20/20 vision with glasses or without glasses?


texts: How are skis stowed on retractable gear aircraft?

texts:
This image of a LC-130 taking off from a snow runway shows that in addition to wheels on the landing gear, it's also been equipped with skis.

Source: Wikimedia Commons.We're getting a lot of use out of this image lately!

How do these skis get stowed when the gear retract?

Do the skis become part of the gear door?
Is there enough room in the gear bay for the skis?
Are modifications to the gear bays necessary to accommodate the skis?
Is there any modification necessary to the movement of the gear to accommodate the skis? (i.e. some gear rotate as they stow. I'm not sure if the C-130s do or not.)


texts: Do any companies offer 'ejection' experiences?

texts:
Most airlines now offer fear of flying courses, most airports provide flying lessons and some specialist companies offer zero-gravity flight experiences.

Are there any companies that provide 'ejection' experiences, where you can fly an aircraft and eject from it at a pre-determined location?

Please note, I'm not talking about sky-diving. I want to actually use an ejection seat.


texts: What constitutes a wind gust in a METAR report?

texts:
In a METAR report gusts of wind are shown with a G after the wind speed.  When will gusts be reported?  I have seen reports that show:

12017G20
12010G20
12003G20


texts: What is a weight-shift-control category aircraft?

texts:
Aircraft categories include:

Airplane
Rotorcraft
Glider
Lighter than air
Powered lift
Powered parachute
Weight-shift-control

I'm familiar with all of these except for weight-shift-control.  What are they??


texts: What does "restricted category" mean on the load sheet for a Cessna Citation 560XL?

texts:
I would like some feedback from regarding this Loadsheet. Does anyone know what 'Restricted Category' means?
This is a Loadsheet meant for a Cessna Citation 560XL, the calculated moment values are wrong. The second photo shows the weight limit envelope. But the maximum values, MTOM, MLM etc are wrong again for a Cessna Citation 560XL


texts: What measures prevent a military aircraft's weapons from being fired on the ground?

texts:
Recently the 20mm cannon of an F-16 was accidentally fired on the ground by maintenance personnel at Florennes Air Base in Belgium, resulting the the destruction of another F-16 and damage to a third.

https://theaviationist.com/2018/10/14/f-16-completely-destroyed-by-another-f-16-after-mechanic-accidentally-fires-cannon-on-the-ground-in-belgium/

What measures do  military aircraft have to prevent their weapons from being fired while the plane is on ground?


texts: Where is the inlet for the APU on a Fokker 70/100?

texts: I can see the exhaust for the APU on a Fokker jet, but where is the inlet?


texts: What qualifications are required for an authorized flight instructor to teach IFR in AATD simulators, in the U.S.?

texts:
I'm from Brazil, and I am working on an IFR certification process via AATD Training Course. We are having problems with the flight instructors; they must have valid IFR and CFI licences.

The instructors are pilots with more than 10000 hrs, that have already flown heavy jets and executive jets.  Our national agency is not accepting our training program because they don't fly anymore and they don't have valid licences.

I would like to know how the certification process works in other countries, such as the US or in Europe.


texts: Is it coincidence that the B-2 and YB-49 flying wings have exactly the same wingspan?

texts:
Development of the Northrop Grumman B-2 Spirit began as far back as 1979; however, this was nearly thirty years after the last flight of Northrop's earlier flying wing the YB-49.

There aren't many apparent similarities: engine position, wing-sweep, shape and control surfaces are all different. Yet they have identical wingspans of 172 feet or 52.4 m.

Is there something special about this particular size? Did Northrop mutate their earlier design (through wind-tunnel testing etc.) from one to the other, or is it purely coincidence?

 B-2 source

 YB-49 source


texts: What are different types of weights of an aircraft?

texts:
When looking at different aircraft's specifications or in POHs/AFMs, there are several different weights of the aircraft mentioned (e.g. maximum take-off weight, maximum landing weight, operating empty weight).

What do they mean and how they are different?


texts: In terms of communication with a computer with the receiver in a glider, is there a certain frequency I should consider?

texts:
I am part of a university team of engineers that design and manufacture a plane. My sub-team is in charge of designing an autonomous glider that needs to deploy from the plane and land in a given zone.

Here is my question. In terms of communication with a computer with the receiver in the glider, is there a certain frequency I should consider for proper communication? Or is it not needed at all?


texts: How are missiles attached/detached from a combat jet aircraft?

texts:
What is the mechanism holding a missile onto the hard-point of a wing, and how does it smoothly release the missile when it's ready to fire? What about the electric cables that also need to detach without getting caught?
I just want to get an idea of how simple or complex it is. I hope it's not some hydraulic "nightmare" device.


texts: What fuel would a Bell Huey helicopter use in 1964?

texts: What type fuel would a Bell Huey have used in 1964? If that matters, let's say for a medical evacuation situation


texts: How would you go on about identifying the load paths on an empennage structure, wing and fuselage?


texts: How do you communicate with a military drone operator over radio?

texts:
This article (and other similar ones) states:

  In remarks at the White House on Thursday, US President Donald Trump said the drone had flown to within 1,000 metres of the USS Boxer and had ignored "multiple calls to stand down".

For airplanes, ICAO standardizes 121.5 MHz and 243.0 MHz (military) as common emergency frequencies that aircraft "should" monitor when possible. If approached by an unknown aircraft, this is the frequency I'll try to raise the crew on first.

How does this work for drones? Does the same standard apply? Is it reasonable that in this case the USS Boxer's crew could expect that the drone is monitoring 121.5 (or 243.0) and that its operators will be listening?


texts: Which international routes might save fuel and time by using a potential newly "deemed safe" North Korean air space?

texts:
The Reuters News item Exclusive: U.S. blocks North Korean air traffic revival ahead of Trump-Kim summit - sources says:

  If the space was deemed safe, international airlines could save fuel and time on some routes between Asia and Europe and North America, and North Korea could begin reviving its own commercial aviation industry.

Question: Which international routes in particular, flown by international airlines could save fuel and time on some routes between Asia and Europe and North America by using newly "deemed safe" North Korean air space?


texts: What are these beams sticking out of the Su-17's nose?

texts:
As visible in the image above, there are these 2 beams sticking out of the Su-17's nose. One is longer and one is shorter.
What are the purpose of these beams and exactly what do they do?


texts: Why doesn't G-force knock this pilot out twice?

texts:
In this video an F-16 goes into a dive after the pilot loses consciousness. The Auto-GCAS corrects to avoid a crash, and the pilot regains consciousness and pulls up even harder. Why doesn't he pass out a second time?

According to this article and the G-force meter (at the top left) the pilot:

Goes into turn and loses consciousness at about 8g's.
The Auto-GCAS rolls and pulls up to a limit of 5g's.
The pilot recovers consciousness and pulls up to 9.1g's.
Pilot responds to radio calls to cancel the exercise and gain altitude.

It seems he held the recovery for quite a bit longer and at higher G-forces than the turn that made him pass out. I assume he also didn't have time to do anything breathing exercises or preparations for a high g maneuver. He is also experiencing the G-forces in the same direction both times (pulling back on the stick).

So why didn't the pilot pass out the second time?


texts: What are the requirements for an airport to be designated as an international airport in the US? Is there a minimum runway size or required customs office?


texts: What are the "beta lines" of a gas turbine engine component?

texts: For a compressor in particular, what do the beta lines represent? I know for a compressor map you have the lines of constant spool speed, and the contours of isentropic efficiency. I also understand the purpose of the surge line and how it acts as a limit for stable compressor operation. I'm not entirely sure what beta lines do though, are they just fractions of the pressure to mass flow ratio that results in surging? Or are they something else?


texts: Why does the radar dome on the E-3 have a white stripe down the middle?

texts:
Every picture I can find of the E-3 has a blue/black radar dome on top with a fairly thick white stripe down the middle but I can't figure out why.  Is it related to the position of the radar unit inside perhaps?  why is it marked like this?

An example E-3 aircraft, credit: wikipedia


texts: Is the callout "minimums" on the 737 used to describe DH on precision approaches

texts:
So, I have heard that decision height (DH) is used to signify the height on a precision approach which the pilot has to decide whether to continue or not.

But, in the 737, I only hear "approaching minimums" and "minimums". There is no "approaching decision height" and "decision height" callout. Is "minimums" used to describe DH too? Or is there something I'm missing?


texts:
I was reading Aerodynamics for Engineering Students by Houghton and saw the following graph:

A lot of other sources say that increasing camber increases CLmax, like the graph below.

I am a little confused by what camber actually does to CLmax? An explanation which focuses on the physics would be very helpful!


texts: How do airplanes maintain separation over large bodies of water?

texts: I have read that the oceans are big enough that ground radar stations only reach so far out. I assume that means after a certain distance from the coast they leave ATC services. Do airplanes employ any techniques to avoid traffic separation outside of ATC services aside from following their flight plan and the rules of the airway they are flying, and for an emergency backup the TCAS system?


texts: What is the typical fatigue life of a helicopter airframe?

texts: For military helicopters such as the Sikorsky UH-60 Black Hawk, what is the typical fatigue life of a helicopter airframe (in cycles and hours) ?


texts: Where inside a black box is the data storage located?

texts:
In a news article I saw this picture of a black box from a crashed A320. The article mentioned that finding the black box had lead to some disappointment due to the black box having been damaged:

This got me wondering where the actual data storage is located inside the black box. The cylindrical piece on the left looks like it is designed to be more robust than the rest of the hardware, so I am guessing that is where the data storage is located.

Are the reports of the damage exaggerated in this case? Or is any of the critical data stored in those parts of the device which have been damaged?


texts: What are the common private pilot practices for helicopter off-airport landing in US?

texts:
These questions address the legal aspects of off-airport landing and basically conclude that the relevant laws and regulations are very fragmented.

Aside from the legal aspects, what are common practices and habits in terms of off-airport landing in US for private pilots? Are there clearly identified "off-airport-landing-friendly" states or regions where this is commonly practised?

As a comparison, in Switzerland, off-airport landings are nearly systematically practised by private helicopter pilots. In France, you need an easy-to-obtain authorisation and then make a few calls for each occurence/location, but it is an otherwise rather common practice. In Germany, off-airport landing is a big no go for private pilots. How do things fare in US?


texts: Would it be beneficial to have rotors AND propellers instead of a tiltrotor?

texts:
Would it be beneficial for tiltrotor aircraft if they had BOTH rotors and propellers, instead of the hybrid proprotors that are neither good propellers nor good rotors?
Like imagine the V-22 Osprey with additional propellers for example mounted on the wings, which are turned off in helicopter flight and when the airplane transitions into airplane mode, the turbines switch from powering the rotors to powering the propellers via transmissions and the rotor blades pitch to an angle where the drag is reduced. Then the plane would be only powered by propellers, which are better for airplane flight and could achieve higher speeds. Would that be possible and if so, why has nobody tried to do this?


texts: What is the temperature of the air leaving the combustion chamber of a CFM56-5C? I was wondering as I could only find out that the fuel burns at around 1500 Celsius but this can't be the same as the air temperature because the air/fuel ratio isn't 1:1.


texts: How does thrust relate to horsepower on turbocharged engines?

texts: Could someone please help me understand the difference between horsepower and thrust on turbocharged engines?  I believe I have a good understanding regarding the purpose and operation of a turbocharger, but what I don’t understand is why the overall performance goes down even when the turbocharger is capable of making max PSI below the rated “critical altitude”.  For example, if my turbocharger can produce 40” from sea level to 12,000 DA, why does my climb performance decrease with altitude?  40” will produce max horsepower from sea level to 12,000, but the performance charts clearly demonstrate a loss of climb performance between sea level and 12,000’ DA, and I just don’t understand why.  Thank you!


texts: How do you contact ATC if you want to do RC flying in the US?

texts:
This question talks about flying RC models in US and latest "guidelines" to follow.  One of them is contacting ATC tower if you are within 5 miles of the airport

The seems pretty simple but I'll ask anyway:
How would one go about contacting tower to let them know you are going to be flying RC near airport?

Any specific verbiage that needs to be used?
Can the request be denied?  (Aside from TFRs obviously.)
Does anybody have any actual experience doing this?


texts: Can throttle control be considered as a primary flight control?

texts: My flight instructor asked me if throttle can be considered as a primary flight control?


texts: Could the S.H.I.E.L.D. C-17 actually have a sensible center of gravity?

texts:
In a question about whether tail surfaces add to lift, I thought of a fictional example where the tail surface very much adds to lift: The Agents of S.H.I.E.L.D C-17, highly modified and super-engined.  Presumably the T-tail vertical stabilizer (still present) provides downforce for trim, and the aft wing provides lift; though that wouldn't necessarily have to be so.

And my first reaction was "The center of gravity on this would be totally unworkable." But is that really true?

I mean, it looks like the rear wing would account for about 20% of lift, maybe a tick more because it is being blown by the forward engines.  So if you marked the main-wing center of lift and the aft-wing center of lift, the aircraft CG would need to be inside that range, about 20% aft of main-wing.

Would that put the CG aft of the rearmost landing gear wheel?  Wouldn't it "pop a wheelie" the moment they lost elevator authority?

But then, if their Stark/Asgard/Tesseract tech can get 150,000 lbf out of a PW2000, maybe they can move the landing gear aft.

If you haven't seen Agents of Shield, spoiler alert...

    One hat-trick that aircraft can do is "tip the engines up" and go into full VTOL.

 The cattywumpus angle of some of the engines are dynamic adjustments for station keeping; this is obvious in the video.

 That seems to place some very particular demands on Center of Gravity,  noting that the engine lift is significantly forward of wing lift.  Especially when you fail an engine - worst case being a tail engine.  Presumably, everything is specced so a single engine rollback in VTOL/hover mode could be easily compensated for. Clearly, that would factor into CG also, as the loss of a tail engine would be the worst case, necessitating the CG stay fairly forward.

 Would the CG for forward flight be compatible with the CG for vertical hover?


texts: What does "Request Boxing Vectors" means?

texts:
I have heard on a request from a pilot: "- Request boxing vectors!"

What's the meaning of this non standard phraseology?


texts:
What is the best glide speed for the DC-3 with 2 engines out?

I realize we may consider best speed for ground distance traveled or best for duration - and that weight can be a factor. I can't find anything on the web.


texts:
As I understand the procedure for go-around it includes retracting the flaps.

Why is this?

The decision to make a go-around must sometimes be made quickly, under stressful conditions, like in bad weather. Retracting flaps introduces one more thing to do under sometimes stressful conditions.

Speed is low during landing and by retracting flaps you give away safety margin for lift. (Speed may also slow further since the nose is raised during go-around.)

Retracting flaps may also affect pitch and thereby make control of the aircraft slightly more difficult in a situation which may already be stressful.


texts: Why can’t level D simulators produce a G-force effect?

texts: From what I know so far, simulators can’t simulate this feeling, I’ve heard some say it will never be possible. Is that true? There’s really no way of producing this in a simulation?


texts: Does having permission waive the 500 foot distance requirement in 91.119(c)?

texts:
The FAA expressly forbids flying within 500' of people, structures, etc...:

§ 91.119 Minimum safe altitudes: General.
Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:
.
.
.
(c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.

It's hard to find much wiggle room in the plain meaning of this statement. However I feel like there would be an exception when either the structures in question are your own (or otherwise authorized by the owner) or the people on the ground are somehow participating in the flight (such as judges for a flour drop).
Nonetheless, no exception exists in 91.119(c). Is there an exception anywhere else, perhaps in a LOI or AC?


texts: How long can a passenger aircraft glide without engine power?

texts: Assuming that the aircraft is cruising at 36000 ft and lost engine power, how long could a passenger aircraft glide?


texts: A group of students and I are designing a theoretical closed-wing drone and need to calculate lift based on the NASA lift equation. We've designed fixed-wing aircraft before and when it came to finding the co-efficient of lift for the airfoil, we just used the NACA charts. Since the aircraft will be closed wing this time around, we are not entirely sure how to go about this. We are very amateur, so I know we are likely missing very obvious things. Thank you for any help that can be provided.


texts: How critical is it if a pebble blows into a propeller?

texts: How critical is it if a pebble blows into a propeller while taxiing and leaves a small abrasion in the leading edge? It wasn't noticed during flight and there was no apparent change in performance of the airplane, it was only noticed after parking. This is on a single engine piston aircraft.


texts: Which features identify an aircraft as a "Sixth Generation Fighter"?

texts: I've been seeing all this news about how the Navy and Air force are going to get some new next gen fighter jets soon. However, I was wondering what will be the difference that makes it 6 gen instead of 5 gen. Will it be faster? More stealthy (if that's a word)? Or does nobody know? Thanks!


texts: In theory which causes more parasitic drag? A large smooth wing or a small, rough exhaust port?

texts:
I'm new to aviation and I have a basic, mechanical question.  Wings produce a lot of lift-induced drag, especially at lower speeds.  But according to this chart that drops off as velocity increases.

However despite the fact that lift drag declines as speed increases the wings still represent roughly 70%(+/-) of the surface area of an aircraft and they do produce parasitic drag.

So my question is despite the enormous surface area that the wings represent do small, irregular shaped items such as exhaust ports produce more parasitic drag as a plane nears its top speed?

The pictures below are from a P-51 which has a top speed of over 400mph.  At that speed is the wing or the exhaust port the biggest drag producer?  Or is this maybe a close call?

Thanks so much for any input!


texts: Will ATC proactively route traffic around bad weather?

texts:
When thunderstorms or other severe weather crop up, will the Air Traffic Control in the area proactively route traffic (horizontally or vertically) around the trouble area, or do they leave it up to the individual pilots to request an alternate route?

My intent was asking about commercial aircraft flying IFR, however the information about general aviation and VFR is appreciated


texts: Why does the Information Manual say "C172S - Flaps 10 (Preferred) for Normal Takeoff", when the models before S-model do not have this note?

texts: Do Flaps 10 really do anything performance-wise other than reducing ground roll and distance over a 50-foot obstacle? If not worried about clearing an obstacle, does a Flaps UP-normal takeoff make more sense (Better climb performance since no drag from Flaps) in the C172S?


texts: Will having a history of depression prevent me from flying?

texts:
The AOPA website lists four medications as acceptable treatments for depression. I was treated with one of them, but it ended up making things far worse, to the point where I had issues with suicidal ideation. I've since stopped taking it and, while I'm still somewhat depressed, no longer have those thoughts, and don't have any issues getting along with daily life.

My depression is more along the melancholic lines, so I basically just don't find most things enjoyable. Being in the air is one of the few things that helps, so obviously I'm worried about not being able to do so. I don't have any of the symptoms that would seem to have an impact on actually flying, but I know having a history is a problem, so I've been trying to figure out how much this will affect things.

Not sure if aircraft type matters for medical requirements, but I was hoping to either fly helicopters commercially, or in the very likely case that I can't find a helo school, I'd probably end up crop dusting.


texts: In the compressor characteristic, what does this value represent?

texts:
$$ ? = \frac{m_t* \sqrt{T_3}}{P_3}$$

All I know is that it is a material property of a turbine, it has something to do with the mach number, and is used for calculating $W_T$. It's kinda similar to the corrected mass flow rate but I guess I'm wrong.

I don't have any books on aerodynamics and I feel kinda lost...


texts:
This is Ramstein air base in Germany,

Why would you want to have runways converging (or diverging) like that, doesn't seem to do you much good in terms of parallel usage (either the approach, or the go-around would be exciting).

The only reason I can think of is that it gives you more separation when launching aircraft in rapid succession, but then again only in one direction. And it's not like the military would bother much with separation anyway when there's a – shall we say – pressing reason to get in the air fast.


texts: I came across this photo but it doesn't have any other info. What type of plane is it? Also, is it some sort of seaplane perhaps? I say seaplane because it was tagged with the word "seaplane". Seems Cessna-ish to me but I'm clueless beyond that. Is it possible to identify the exact model?


texts: How does an airliner adjust and move exactly over the coloured lines before stopping in front of the jetways?


texts: Why did the altimeter in an F-16 jump suddenly as it passed through Mach 1?

texts:
In this video, Destin — the creator of YouTube channel Smarter Every Day — rides in an F-16 with a USAF Thunderbirds pilot. If you start watching the video at the 11:06 mark, you will see what happens when the aircraft passes through Mach 1, namely, that the altimeter reading suddenly jumps.
Destin explains that this jump in the altimeter reading is because the air pressure downstream of the normal shock wave that is impinging on the pitot-static tube of the aircraft is lower than the air pressure upstream, but by the laws of compressible airflow, this would be total air pressure, not static air pressure.
As static air pressure, which is sensed by the altimeter, is always higher downstream of a normal shock wave, why is it that the altimeter reading registers a sudden jump and not drop instead?


texts: Is it possible to have dual contra-rotating rotors on a gyrocopter or gyroplane? Are there disadvantages that would outweigh the extra lift?

texts:
Is it possible to have dual contra-rotating fixed-pitch rotors on a gyrocopter or gyroplane?

It would seem to me that it would provide a lot more lift.  I am wondering if any disadvantages would outweigh the extra lift?


texts: How does a student pilot learn the process of pre-flighting a Robinson R22?

texts:
I've watched a few youtube videos on pre-flighting a Robinson R22 helicopter, and I'm always impressed by the way the pilot methodically does the external checks and the internal pre-start, start-up and warm up.

For me, there's a big gap: knowing what to check (because the checklist says so), and being able to identify it (put your finger on it / point to it), and knowing how to check it.

How does a student pilot learn the process?
How long does it take to master the process?

Assuming being able to pre-flight is a pre-requisite for flying solo, and a private pilot has one lesson per week, and there are say 20 1-hour lessons before solo is even considered, then 20 opportunities to learn such a complex set of processes does not seem enough repetition and re-enforcement somehow, and the risk of stuffing it all up seems very high.


texts: Many 737 engines have an accessory gearbox on the 9'o clock position, which is part of why the engine has a flat-bottomed shape. What exactly is an accessory gearbox?


texts: Do the FACs compute every speed value shown on the PFD speed scale, or only stall speed and maximum speed?

texts: On an Airbus aircraft, the Flight Augmentation Computers (FACs) control the rudder and have windshear detection, and the FACs also are responsible for speed computations. I know the FACs continuosly compute stall speed and compute the maximum speed but do the FACs also compute every other speed on the speed scale; VLS, alpha protection, alpha floor, green dot speed, flap retraction, etc., so basically the FACs compute every speed on the speed scale?


texts: Could a plane with an electric turbine engine generate enough lift to provide a electric areodynamic lift and runway to space?

texts:
This question is similar to my previous ones but configuration is different and so is the question.

Could a modified electric turbine engine (E-Fan) plane create enough of its own lift not to burden an electric rail that is evenly supported by electric powered blimps and rail (similar to a 3rd rail of a train) while carrying a payload (like the space shuttle) to the edge of space? The problem with a high power electric engine is the is the supply of electricity and weight of the engine and battery . The blimps and rail are necessary to provide the amount needed without a huge battery. Rockets still can be used at the end of it.


texts: How do you calculate total drag on a wing?

texts:
I'm not an aeronautical engineer, but I am making a brave attempt to perform a preliminary design for an 4-metre wingspan radio controlled glider. With special thanks to @mns I have now learned a formula for calculating the coefficient of induced drag. The question now is how do I use it to calculate total drag.

Considering the formula below, how do I make a reasonable estimation of efficiency factor (e)

I've selected a prismatic inner wing with tapered outer wing to assimilate an ellipse? I understand that they state that (e) for a perfect ellipse is 1. What is 0 then, a square? Here is my wing planform:

They then state that I should add CDi to CD0 to offer me a total CD.

The question I ask now is why add CD0 (That is CD at 0 degrees AoA if my angle of incidence (setting angle of the wing) is 6.25 degrees?

I assume that I then run this through the lift formula to get drag in newtons.

The curve for CD / Alpha can be seen here


texts:
I am very interested in the principles of take-off performance optimization.
During my research I found an interesting picture, showing the software used by a European carrier.
However, the output presented shows a value I do not understand:

In the lower right corner, the following values are shown:

PTOW: 68.5
Field Length: 73.2
Sec. Segment: 71.0
Obstacle: 68.5

I do not understand what the Second Segment limit stands for.
I know about the different phases of the take-off run, however I am not aware how the Second Segment could be limited by any other weight than the Obstacle Clearing weight.


texts: How does compression ratio change, if at all, from sea level to higher altitudes?

texts:
As I understand it, compression ratio is the max pressure inside the engine divided by the ambient air pressure. This is for turbojets and turbofans.

Sea level pressure is about 100 kPa. An altitude of 10 km would have an ambient air pressure more like 26 kPa.

So you would think the compression ratio must drop 4x, but the thing is, does the turbine spin any faster at high altitudes to compensate?

So how does compression ratio change, if at all, from low to high altitudes?

Edit: Maybe I should have started with hard figures. What are typical compression ratios for turbojets and turbofans?


texts: Can bird strikes be dealt with by throttling down engines to idle?

texts:
From a related question, I got to thinking about bird strikes again and the fact that they are sucked into the engine at great velocity.

If a pilot had 5 to 10 seconds of warning time, would throttling down the engines to idle be a good idea? Would it save those engines even if a bird hit the intake fan? This would of course be a temporary measure, intended to prevent the birds being sucked in harder or faster than otherwise. Once the birds passed, the engines would be throttled up again.

I'm thinking about large commercial jets like the Airbus A320.

EDIT: one concern I have is that at high throttle, the engine will suck in objects from a wider area than just the engine inlet. Is this assumption true?


texts: Where are the flap track covers on this wing?

texts:
I don't see it has covers for the flap tracks, so,where are the covers for the flap tracks?

Image taken from the English for Aviation book (Oxford).

The aircraft is a Vickers VC10


texts: Does Active Thermal Imaging (NDI method) detect all types of structural faults in modern civil aircraft?

texts:
What are the weaknesses of Active thermal imaging in NDI of different composite materials used in aircraft structure ?

How much time and effort does it take to complete a full structure inspection with the latest portable equipment like (C-CheckIR)


texts: What happens when auto-pilot fails over the ocean?

texts:
Let’s assume the current location puts the aircraft 2 hours from the nearest airport, but the destination is 2 1/2 hours away.

Would the pilots hand fly the rest of the way?
Are they allowed to fly to their destination, although it’s just an additional 30 minutes?
And how difficult would that be (For the sake of the conversation, we can say I’m specifically asking about the 787, but I am generally interested in long distance capable aircraft)? Or is there tons of ways to fix the auto pilot?

In short, what I’m asking is: how difficult it may be for two pilots to manually fly for this long, is it a big enough deal to cut the flight short 30 mins to land elsewhere?

I'm not sure under what rules, and not sure how the auto-pilot fails either.


texts: What is the purpose of a small wing near the cockpit on the front of some planes?

texts:
I saw a plane leaving Luton Airport that I have never seen before.
It seemed to have an extra small rectangular wing near the front of the plane. What is it?


texts: What is the role of an intermediate fix?

texts: There are the IAF and the FAF, which has clear roles. One is where you start the approach and the other where you start to descent and end the approach. But what is the purpose of an Intermediate fix?


texts: How would one define or explain the term "unloading the controls?"

texts:
I've heard people say "unload the controls" or "unload the wing/propeller."

What does this mean exactly? It is usually followed by releasing back pressure on the elevators or starting/ending a turn.


texts: Is it feasible to recuperate energy from landing aircraft by using a runway sled with regenerative braking?

texts: Would it be feasible to land large (Boeing 747 and Airbus A380) and all other aircraft on a sled on the runway, the kinetic energy of the aircraft is then transferred to the sled, then the sled uses regenerative braking to produce electricity for use by other electric sleds that taxi the aircraft to the runway for taxi, given that a lot of fuel is used during taxi and that fuel is expensive, causes green house gas pollution when burnt. This would save costs on tire wear brake pad wear and if designed properly improve braking safety


texts: What is a typical Cd0 value for single-slotted flaps?

texts:
I've been having trouble finding any source for what a typical value would be for single-slotted flaps. I haven't been able to find any information within Anderson's Aircraft Performance and Design or any other resource readily available.

Thank you so much!


texts: How does the rudder on the Rutan Long-EZ work?

texts: I wonder if someone can explain how the rudder on the Rutan Long-EZ works. I have an idea that it is the induced drag which yaws the plane.


texts: Would An-72-like (or any anhedral wing multi-engine aircraft) cruising at high speed, roll counter intuitively right, if left engine suddenly dies?

texts: Assuming low angle of attack & anhedral wing configuration. (and as a consequence of natural left yawing moment)


texts: If I recall correctly, the best competition gliders have a L/D ratio as high as 60:1. What imposes this limit? Is there a maximum theoretical L/D ratio, or could sufficiently advanced materials allow a glider with a L/D ratio of, say, 200:1?


texts: Does the RA (resolution Advisory) from TCAS II take into account the stall margin required?

texts: A resolution advisory from TCAS indicates the vertical speed per minute that you must use to avoid conflict with the other traffic. Does this vertical speed given by the RA take into account the stall requirement for the aircraft?


texts: How far back from the final approach fix can you intercept the glideslope?

texts: I was looking for the point that you engage your auto pilot approach glide slope before the final approach fix in this question. How far back can you go?


texts: Could New York build a new mega airport?

texts: Both New York and London have insufficient air traffic capacity. One option for London is to build a new mega airport to replace LHR. However, this option is not discussed much in NY. Would it be feasible to build a new mega airport to serve New York?


texts: What is the meaning of "regular pitch" when applied to a propeller?

texts:
I am looking at parameters of a propeller that looks like this:

  3 blade xx inch diameter (regular pitch)

What does "regular pitch" mean?


texts: The Mig 21 and the Mirage III have been criticized for lack of range, is this a limitation of the wing configuration?

texts:
Mig 21
Range: 1,470 km (910 mi; 790 nmi) at 10,000 m (32,800 ft) with 2 × K-13A missiles and 800 l (180 imp gal; 210 US gal)
(Wikipeda)

J-7
Combat radius: 850 km (459 nmi, 528 mi) (air superiority, two AAMs and three drop tanks)

JF-17
Combat radius   1 350 km

The J-7 and JF-17 are developments of the Mig 21, why is their range greater?


texts:
I see lots of great questions related to Victor Airways, but I haven't seen any which indicate why someone would want to fly one or what really makes them special or unique.

I get that they are radial of a VOR to another VOR and that certainly provides an indication in determining what that radial is if you wanted to fly from one VOR to another, but I do not understand the value of defining it as an airway beyond that.

What is the purpose of indicating things such as width of the Victor Airway, or altitude or any other attribute? Is the concept that it would be frequently travelled and thus these attributes make it a little more controlled and thus safe?

In short: Other than providing an easy way to determine a radial from one VOR to another, what is the purpose of a Victor Airway?


texts: How is the same takeoff performance achieved by a specific engine type on aircraft of different sizes?

texts:
The entire B737Max family (B737Max7,8,9,10) uses CFM International LEAP-1B (Source) engines, despite the B737Max10 carrying up to 60 more people than Max8.

My question is how do all of the aircraft in the family achieve the same takeoff performance, despite such a remarkable difference in their size, with the same engines?


texts:
The diagram shows the B777-200LR Payload/Range for 0.84 Mach Cruise (P.41 of Source)

The maximum payload range is around 7600 nmi, and after that payload have to be reduced in order to increase range. While the Operating empty weight of 777-200LR is 320Klbs, the horizontal-coordinate(range) of the diagram is around 10500nmi at 350Klbs, and there is a gap of 30Klbs.

Does that mean B777-200LR has theoretical maximum range over 10500 nmi if OEW plus payload is below 350Klbs? And how far can it fly potentially?


texts: How do you know if an aircraft engine has a supercharger?

texts: The engine I'm specifically thinking of is for the C-130J Hercules, it's the AE-2100 D3.


texts: It was flying over Delhi, India 6:41PM IST May 22 2021


texts: How close is a pilot allowed to get to a runway without landing clearance?

texts: I heard it was 100 feet above minimums, I'd just like verification.


texts: Which American State Aircraft use the RVSM exemption?

texts:
Reading about RVSM, I noted the exemption for "state aircraft." This is summarize in wikipedia as

  "State aircraft", which includes aircraft used in military, customs and police service, are exempted from the requirement to be RVSM approved. Participating states have been requested, however, to adapt their state aircraft for RVSM approval, to the extent possible, and especially those aircraft used for General Air Traffic (GAT).[4]

The topic of RVSM has also been addressed here before. My question is specifically whether a particular United States "state" aircraft or mission regularly makes use of that exemption (INCONUS or OCONUS.) I would imagine that in order to avoid burdening ATC / ATS, military and government aircraft would try to operate above and below RVSM airspace as much as possible but perhaps there is an example of a case where that is not true?

I am particularly interested in knowing not only which aircraft (or models of aircraft) regularly make use of this exemption but what the justification is for doing so. After all, if FAA literature is true, flying a state aircraft at these altitude halves the capacity of the airspace. Would fuel economy be a sufficient argument?

I'm also curious about the "manufacturer" exemption. I'm sure that operating NON-RVSM would not be included on a Letter of Intent without good reason. What would those good reasons be? Testing new RVSM equipment? :)


texts: Should I inform ATC about minor deviations to maintain VFR while on practice instrument approaches?

texts:
When talking to approach control for the purpose of performing practice instrument approaches in VMC with a safety pilot, the pilot (and safety pilot) is required to "maintain VFR." However, the pilot is also required to follow the controller's instructions and vectors.

When maintaining cloud clearances in order to comply with the "maintain VFR" requirement, it is sometimes necessary to maneuver around, under, etc. small clouds. Sometimes the maneuvering involves a lot of small corrections: maybe a few thousand feet off course, or going under a cloud by 500 to 1000 feet.

Do controllers expect to be told every time a VFR aircraft in VMC has to maneuver around small clouds? What phraseology is required? For example, is "maneuvering to maintain VFR" sufficient, or do you have to state each turn descent/climb etc.? At busy approaches it seems like a huge annoyance to controllers to call with every little course correction/adjustment to maintain VFR, but perhaps that is what they expect.


texts: Is ultrasonic noise from small turbines painful to pets?

texts:
A question on another SE site prompted me to search for 'Aircraft engines untrasonic noise dogs', but with not much success.  The OP's dog barked like crazy at turboprops, but was not bothered at all by 'louder' noises from light GA planes with piston engines, even when led next to them as the engines ran up on the ground.

Does anyone know how much ultrasonic noise does a small turboprop put out?  I suspect that it may be worse, in proportion, to that from the large turbofans on airliners since the hp shaft revs so high on those little engines.

Maybe that noise that is merely an annoyance to humans is actually painful to dogs etc?


texts: How does one reverse direction on a VOR radial?

texts: Tracking inbound, say on R-270, how do I track outbound on the same R-270? What intercept heading shall I fly?


texts: I saw a video of a test flight of a GA plane and it stalled with max power and with a moderate AOA (angle of attack). How can a plane stall with max power (with the wings flying below the critical angle of attack)?


texts: What happens when two different control inputs are commanded in an aircraft with two control columns?

texts: For example, the captain starts pulling back and to the right to turn right. First officer initiates a left diving turn. What happens?


texts:
The seats leading to an emergency exit normally offer more legroom and, therefore, the airline can cash a fee for them.

But, shouldn't they pick passengers that would have the higher chance of being able to open the door in case of an emergency?


texts: What happened to the 737's cockpit skylights?

texts:
Older-model 737s had very distinctive set of upwards-facing windows above the main, forwards-facing cockpit windows; not unlike those you'd find on MD-80-series airliners and on 727s.

These windows appear to also be present on early-model NGs (or retrofitted classics; I have a hard time telling, and absent on later-model classics; specifically ones with high-bypass engines).

(Photo likely by Maor X on Wikimedia Commons)

On later-model NGs and the MAX, however, these windows are gone:

(Photo by Jpedreira on Wikimedia Commons)

Why would these windows, which are arguably useful in giving pilots a better vertical field-of-view, be removed? Has their usefulness in finding nearby air traffic been superseded by TCAS and ADS-B? Even then, why remove the windows when they act as (an extremely reliable, albeit less-precise) redundant system?


texts: Are there reference speeds like V1, Vr or V2 for a touch and go procedure?

texts:
Are there any reference speeds like V1, Vr and V2 on a touch and go procedure?

During takeoff, these are used to mark certain states of the takeoff, including the speed at which the aircraft starts pitching up (Vr -> rotate speed).

But during touch and go, are those predetermined values as well?


texts: What were the effects of the oil crises on the Concorde ticket prices?

texts:
One of the things that is considered to have greatly hampered Concorde's success were the dramatic oil price increases due to the 1973 oil crisis (the 1979 one surely didn't help either, but it was too late already).

Wikipedia tells me that the 1973 oil crisis resulted in crude oil prices being multiplied by four. How much could this have affected Concorde's projected ticket prices ?

This is a very complex question, because I'm really interested in how much this affected the commercial case of Concorde, meaning a standard occupancy rate would need to be considered (ideally what was considered initially for Concorde if anyone has any idea...). But due to the difficulties of Concorde, the occupancy rate was usually very low (surely much lower than projected without the oil crisis), to the point that actual ticket prices surely ended up reflecting that. But that is a triggered consequence I would like to be able to distinguish from the original factor (after that we can of course add the calculation when the occupancy rate gets reduced as a result).

Basically :

Do you know what were the pre-crisis projected stabilized (ie non-initial) ticket prices of a given long range Concorde flight ? That would be immensely helpful ;
Do you know how much a 4x increase in crude oil prices at the time would have affected this projected ticket prices, all other things being equal (same occupancy rate, etc) ? If we knew typical jet fuel prices at the time (pre- and post-crisis), seems like an estimate of the additional "first degree" cost per ticket could be reached by dividing fuel capacity over expected number of passengers. Adding benefit margin and we would have an estimate of price increase.

Thanks.


texts: Why have none of the US /UK/Japanese airlines ordered the Irkut MC-21 yet?

texts:
A new airliner was launched on June 8, 2016 by the Russian company Irkut Corporation.

Source: https://www.flightglobal.com/

The airliner looks good on paper:

Empty plane weight is reduced due to composite and prospective alloy materials and lighter new generation onboard systems
Wide cabin (3.81m), MC-21's cabin is wider than the cabin of an
Airbus A320 by 12 cm and a Boeing 737 by 28 cm. As a result, two
passengers can walk through the aisle without blocking each other.
The wide cabin also supports the biggest luggage racks in its class
in order to accomplish the goals of decreasing MC-21's turn-around
time at the airport (important for charter and low-cost carriers),
providing better comfort for passengers, and making the cabin more
suitable for carriers' purposes
Relatively to the current models MC-21’s engines will emit 20% less
СО2 per passenger seat
High cost operational effectiveness, international certification
under AR IAC, EASA, FAA requirements, individual logistic and
maintenance support during all life cycle will make the aircraft
attractive both for Russian and foreign carriers

Source: Wikipedia

Almost all of the orders look like they come from Russian airlines. But why haven't any US/UK/Japanese etc. airlines ordered any planes?


texts: Where is the official definition of pressure altitude?

texts:
I know that pressure altitude for a certain pressure is defined to be the altitude in the standard atmosphere which has that pressure.

But I can't find whatever standard, regulation, or glossary officially defines it to be so. I tried to look in the AIM, the P/CG, a search of the FARs for "pressure altitude" wading through a ton of results, and what searchable partial copies of the US Standard Atmosphere of 1976 I could find. I don't have access to a copy of the ISO standard that defines the International Standard Atmosphere.

Does anyone know of an FAA, ICAO, or ISO document providing this definition?


texts: What is this smoke coming from an airplane wing when it is landing?

texts:
I noticed that when an airplane is landing, the end of the wing emits a smoke like the one here: .

What is that?


texts:
I mean, on the one hand it seems kind of obvious, if you had a fuel tank that was mostly water then you would lack combustible materials for the engine, but I get the impression that having any water in the fuel tank at all is considered a really bad idea.

Why is that?  Is it all right to have a very small amount of water in the fuel tanks?  Is there a defined percentage of liquid in the fuel tank that must be fuel in order to operate safely? (say 99.87% or something?)  And does this differ from prop to turboprop to turbofan to jet?


texts: What is the equivalent height of a parachute landing?

texts:
I understand that this will vary depending upon the equipment used, the bodyweight of the jumper, barometric pressure etc, but what is the approximate equivalent height of landing from a parachute jump? I have heard people say the impact is equal to jumping from 6 feet up onto the ground - and yet I have seen members of the Red Devils land seemingly as easily as stepping off a kerb.

(Mods: I have seen this question which is why I ask here, please relocate to the appropriate SE if off-topic)


texts: When a pilot receives the message : THE RUNWAY IS STERILE, what is the meaning?


texts:
look at this   video from 18:00-21:00 ,Al Bowers talk about benefits of bell spanload compare to classic eliptical..Can someone explain what does it mean in practice examples when design aircrafts:

1)So if we have plane with 3000kg and we must have best L/D  and if wingspan  is not constrain,then we must choose bell spanload so our new wing will be 22%longer and it will has 11% smaller induced drag?

2)Why Al Bowers  talk like airplane overall weight and wing bending moment are  same thing?If some plane have bigger wing bending moment,that dont neccesery mean that it has larger weight than plane with lower wing bending moment...

3)Why all gliders use eliptical spanload if bell spanload has better L/D?

4)What do you think,when will aircraft  industry  switch to the bell spanload solution(if ever)?


texts: Is ADS-B UAT required below 18,000 ft for ADS-B ES equipped aircraft?

texts: If an aircraft is flying in the USA with 1090 MHz Extended Squitter (ES) and it is below 18,000 feet, does it then need to also have 978 MHZ Universal Access Transceiver (UAT) so that aircraft flying below 18,000 equipped with 978 MHz (UAT) can detect it?


texts: Help in understanding this velocity triangle of a propeller

texts:
I was reading a research paper and have had difficulty understanding something. How did the author get tan(phi) in these terms?
This is something I've been trying to figure out for a long time now.


texts: How HF wire antennas on older aircraft are protected from lightning and static discharge?

texts: For HF antennas installed on some older aircraft with wires running from points on the fuselage to the tail, what precautions are used to prevent lighting strikes or P-static accumulation from damaging the HF antennas or interfering with the communications? Are the wires shielded and would that be enough to prevent damage if lighting strikes?


texts: What flaps and throttle settings are used on takeoff, climb, cruise, descent, and landing?

texts: What degree of flaps and throttle setting are used on takeoff, climb, cruise, descent, and landing? This question is for private and general aviation aircraft. I have looked everywhere for FAA manuals on this but I can't find anything, if there is a manual please link it.


texts: Why isn't the point you begin descent part of the flight plan?

texts:
In This question there is discussion about how to determine when to start the descent from cruise. There are several factors at play and it is usually calculated for maximum fuel performance.

Would this calculation not be done ahead of time, especially for aircraft cruising in class A airspace (presumably by dispatch for part 121 ops)? Why is this not included in the filed flight plan? Wouldn't ATC want to know when to expect this, especially if you lose coms?


texts:
This may be a little off topic but I could not find a better community or website.

I have two photo postcards with a man in front of a plane. Pretty sure it's Charles Lindbergh but an exhaustive Google search for anything related visually has only turned up another picture of CL with a similar jacket on. So is this who I think it is? Can anyone come up with a "verifiable" narrative to accompany these photos? Perhaps the type of plane in the background?


texts: What is the flight that returned to base after dumping fuel due to toilet issues?

texts:
From this post I got to know one of the flight has emergency landed due to LAV tank full and Lavatory was In-operative.

Can someone please share the flight details that made emergency landing due to Lav in-operative or Lav is full? This will help in my study (white paper publish).


texts: I took this photo from the Wikipedia entry on afterburners. What's the circled aircraft in the background behind the Phantom?


texts:
I had a question regarding thrust calculation for an aircraft during cruise. For an aircraft flying at a constant cruise altitude and a constant Mach number (level unaccelerated flight), what exactly is the weight we use in the equation T = W/(L/D) while calculating the thrust?
What I understand is that since the mass of the aircraft is continually reducing due to constant fuel consumption, therefore the lift requirement will change. Assuming a constant L/D ratio, that implies the drag will change leading to a constant change in the thrust. Therefore the cruise thrust is not a constant value. So how can we apply the above equation for a calculation of the thrust anyway? Is it a thrust at some specific point during the cruise?


texts: What is this tube connected to a 757 for?

texts:
In this photo, there is a 757 at Narita Airport with a tube connected to the belly.

Source: Airliners.net
The tube is in the middle of the plane.
There is a similar question about this tube, but here it seems to be connected to the ground and not to the jet bridge.
Does anybody know something about this tube?


texts: On the new A320s when we do a brake check there is no need to call pressure 0 why?

texts: Why do we have a give a pressure 0 call out when checking brakes while taxi on the old A320s but not in the newer A320s.?


texts: Why do flying wires hum louder in a sideslip?

texts:
Page 50 of the Feb. 2021 issue of the EAA's magazine Sport Aviation reports that

Like any good vintage airplane, the Sea Bird likes to fly coordinated,
and the flying wires will sing out loud if the
ball
gets off-center.

Why would the wires hum or sing more when the airstream impinges from one side?
All else being equal, a sideslip converts some of the flow's transverse component to an axial component, from the wire's point of view.  (Like many airplanes, the Sea Bird's rigging is mostly parallel to the wing.)  That should reduce vibration, because axial motion in a wire under tension is hard to provoke: try bowing a violin with the bow nearly parallel to the string.


texts:
What's the shortest amount of time a commercial airplane will be on the ground in between flights?

After a commercial flight lands the passengers and luggage have to be unloaded, the airplane needs to be refueled and undergo mandatory inspections, etc.

With all of that going on between a commercial airplane's landing and takeoff, what's the shortest time it would take between flights?


texts: For the same airspeed does the attitude of an airplane change with varying wind directions?

texts: Should one maintain a constant attitude if he wants to hold a constant speed or does the attitude vary depending upon the wind direction?


texts: How is proper CG maintained in ultralight pusher aircraft?

texts: Considering pilot weight can vary 100lbs or more how do ultralight pusher airplanes maintain proper CG range?


texts: Does the first portion of a trip that was < 50nm count as XC on a long trip?

texts: I flew a long trip (> 900nm) but the first leg, where I had a full stop landing to pick someone up, was only 24nm away from my starting point. For the FAA, a cross country trip counts as > 50nm straight line distance from the starting point. How should I log this short leg of the greater XC trip? Just count it all as XC or just subtract the time of the short leg from the XC total in my log book?


texts: How does dropping ordnance affect the weight and balance of the aircraft?

texts:
During a mission, military aircraft often shed a lot of weight from takeoff to landing.

An F-15C (empty weight: 28,000 lbs) carries an internal fuel load of 13,455 lbs (almost a third of take-off weight not including pilot and ordnance).

A cargo plane like the C-17 may perform a combat off-load while airborne.

Meanwhile, the aircraft I worked on in the army were deadlined whenever 1% of total aircraft weight was removed, requiring either the part to be reinstalled or a total reweigh prior to next flight.

Operationally speaking, how are these "fat burning exercises" completed without jeopardizing crew and equipment due to shifting weight and/or CG?


texts: How are the wing control surfaces configured for takeoff?

texts: For regular aircraft (i.e. a typical airliner), how are the wings configured before or during takeoff? Are there any adjustments needed for climb?


texts: Where can I find data sets on jet fuel prices, including futures and options?

texts: I understand that most airline companies buy jet fuel using hedging instruments such as futures and options. I have been searching on the internet data sets of having both jet fuel and option prices. Can someone give me a link or a research paper which has these data values?


texts: Are the requirements for an initial type rating the same across types?

texts:
If a pilot wishes to obtain an initial FAA type rating - say, for a Boeing 737 - are the requirements to obtain that rating the same as if they were getting a type rating for an Airbus A320? If they are different, where can these requirements be found?

Assume that in both cases the pilot is ATP-rated.


texts:
I know about induced drag, parasite drag, form drag, skin drag, wave drag, and interference drag. But I don't encounter the term profile drag often, and I can't find a good definition of it.

Is profile drag the same thing as form drag? If not what is it?


texts: Are there any countermeasures for lasers or the people who use them to blind pilots?

texts:
Yesterday there has been another laser-incident at my local airport LOWG. The laser hit the cockpit twice, but the pilot managed to land the Dash 8 Q400 safely.

I'm taking this recent event as opportunity to ask, if there are any countermeasures at the time, be it in use already or in development, against these despicable people or their lasers?


texts: What are the Takeoff Minimums for aircraft operating under Part 91?

texts: What are the IFR Takeoff Minimums for aircraft operating under Part 91?


texts: What does "ACFT MAX 65/7 " means on lido charts?

texts: What does "ACFT MAX 65/7" on the minima box means? I found out that its related to wingspan and some vertical distance, but I still didn't get the vertical distance thing !!


texts: How do you know if a VOR is High, Low, or Terminal?

texts: Is there any way of telling on both a VFR and IFR chart what type of VOR we are looking at?


texts: How can filling a tube with foam help prevent buckling?

texts: How can filling the empennage (aluminium tube) with Styrofoam stiffen it to avoid buckling as seen in Whingding ultralight?


texts: How many of the airliners that ever existed have been lost in flight?

texts:
Another way of asking this is: Of all the airliners that have taken off and returned to the earth, what proportion have actually landed?

Or another way: If you were born as an airliner, what is the probability that you would die at work?

I'm specifically interested in:

airliners, being used as airliners (for example, not as emergency troop transports)
hull-losses
aircraft that took off and then crashed or were otherwise lost (i.e. not simply destroyed while on the ground)

We'd have to start with the total number of airliners constructed, which at a guess is a number in the region of 50-60 thousand - but perhaps someone has a reasonably accurate figure already collated from available sources.

Then we'd need to know the total number lost in flight - I guess it's just possible someone has such a figure.

It would be interesting to see how the figure changes for aircraft limited to particular eras.

Related questions

A related question has been pointed out in the comments, What percentage of airplanes are involved in a crash in their lifetime?

That's not explicitly about airliners, though in fact most of the discussion there seems to be based on airliners, and it contains some useful figures, including in one of the answers:

  That's a rate of 1.56 % aircraft with a fatal accident, or 1 / 64.

This is just an extrapolation from data about 2014, but it's a start.

However, it is based on incidents that kill people, rather than flights that damage airframes beyond repair, so it is about something slightly different.


texts: What parts of the 787 are produced with 3-D printing (besides air ducts and hinges)?

texts:
This article from 2013 states that about 30 parts of the Dreamliner are 3-D printed, mostly air ducts and hinges.

I wonder

what other parts are produced by direct manufacturing?
why it was deemed essential to resort to printing them instead of molding/stamping?


texts: If a helicopter's tail rotor fails, is it possible to perform an emergency landing?

texts:
In the event of a total failure of the tail rotor, is it possible to maneuver a helicopter to an emergency landing spot that is within, say, 30 minutes flying time?

What are the maneuvers required for a pilot to fly reasonably straight, and how do the aerodynamics work?


texts: Is there a standard that defines all Special Service Requests?

texts: I'm wondering if there's an international standard set of SSR codes. I see some references to IATA standardizing these, however, I can't find a reference to where IATA would publish these codes.


texts: What happens if only rudder is applied in a turn without ailerons? Do the two have to be applied together all the time?

texts: Fresh newbie in glider flying. I was told the joystick (aileron) and the pedal (rudder) should always be applied together when making a turn. My question is, what happens if I only pedals the rudder without applying the stick (aileron)? How is it different from applying only the aileron but not the rudder? And are there times when we should apply just one of the two?


texts: How to calculate ground speed using a map with a known scale and time?

texts:
If an aircraft flies from point A to B for a distance of 8cm on a chart of 1:1,000,000 in 18 minutes, What’s the ground speed?

It’s a multiple choice question and the possible answers are in ratios.
(#45 in the image)

  A. $1:1,105,550$
  B. $1:1,250,000$
  C. $1:1,740,740$
  D. $1:1,074,740$

I can’t change the question but I can explain how it is related to aviation.  The question is from flight dispatcher module Air Navigation, where by in dispatching the aircraft we must know about places where aerodromes are located passing etc and so we learn about maps and charts.. am not off topic the question is 100% aviation related


texts: Is a restricted airworthiness certificate required to operate a Cessna O-2A Skymaster in part 137 operations?

texts: Does a Cessna Skymaster O-2A need to be classified as "restricted" if it is to dispense chemicals over a congested area, in a part 137 operation? The O-2A we're currently flying is classified as standard and the category is normal. It is a surplus army aircraft if that makes any difference.


texts: What is the explanation of this airfoil phenomenon? Why the air from below the leading edge's tip deflected up?

texts: I have difficulties to understand this air phenomenon, why the air from below the leading edge's tip (from below the horizontal line) is deflected up and not just follow the bottom wing's surface? What is the physics explanation of it?


texts:
737 fuselages are built in Wichita Kansas and are transported by train to Renton, Washington, where the plane is assembled.

Why outsource the fuselage all the way to Kansas? The cost of moving the fuselages by rail can't be trivial. Perhaps it's because of state tax credits, or maybe because Boeing bought Spirit Aerospace which was in Wichita?

Apparently the 737 used to be built in Renton: b737.org


texts: Are two people required in cockpit at all times on large commercial aircraft?

texts: It would seem reasonable on large commercial airlines to require that there be two people in the cockpit at all times. For example when the pilot goes to the toilet a member of the cabin crew must enter the cockpit until the pilot's return. Such a rule would greatly reduce the probability of pilots being locked out and reduce problems should they be locked out. Do any airlines enforce such a rule?


texts: Are there any models for planning aircraft placement in hangars?

texts:
I work alone at night doing line operations (fueling, tugging/towing, etc.) and emergency services (police, fire and EMS) at my airport. When a pilot/customer comes in and wants to know if we have hangar space available for their aircraft, it would be nice when planning aircraft placement in those hangars to have figures to scale of various aircraft. That way you can see whether or not a specific aircraft can indeed fit, and in what configuration, before trying as I rarely (if ever) have a "spotter" or a wing-walker.

Or perhaps even software or a computer program. Put in the hangar dimensions and which aircraft are to be placed.


texts:
I've always wondered what the purpose of these "bars" on the nose of the F-16 (and some other military aircraft) are. Are they sensors (if so, what kind)? Are they lightning strips? I can't seem to figure out how to word my search query to find an answer, so I figured I'd ask here!

Source: af.mil


texts: What is the unit for ground speed reported by ADS-B?

texts: Strangely enough, I'm having trouble finding the unit reported by ADS-B on the Internet. Many sites simply refer to it as "ground speed". Is it measured in KPH?


texts: What are the abandoned technologies in aviation industry

texts: And technologies has come to end of to their life cycle  Especially technologies that developed for aviation. This could be a manufacturing technology or an engine rather than avionics or sensors.


texts:
I found this very small airplane in the desert on Google Maps. It appears to have about
a 10 foot wingspan, and is about the size of an SUV (compare to cars nearby).

Location in Google Maps: Google Maps


texts: Are there any calculations involved for designing pulse jets?

texts: Are there any requirements for calculations to determine things like exhaust length, combustion chamber size, etc? Also, does the end of the combustion chamber need to be a semi-sphere, or can it be flat?


texts:
Should an IFR-certified radio's automated nav aid identification feature be considered positive identification? Should manual identification still be performed? Does anyone know if this is addressed in any FAA regulation or publication?

An example of automated identification is found on the Garmin 430. When a nav aid is tuned automated identification takes place and the result is annunciated visually.


texts: When are flight tracks publicly available?

texts:
Is there a way to make sure a flight is tracked on flightaware.com or similar sites?
Similarly, is there a way to prevent a flight's track from being available to the public?


texts:
I'm looking for the average pitch of big planes like an Airbus A300. For horizontal travel, is the plane horizontal or does it have a pitch like 1 or 2° (or more)?

If the plane does not accelerate and has a constant speed, is the gravity of the passengers a little backwards?


texts: Are airline pilots worn out at an age of 55?

texts:
Lufthansa's pilot union is calling for a strike to defend pilot's right to retire at the age of 55. They argue that the stressful job of flying is too much for older people. This provokes two questions:

What fraction of pilots takes advantage of such a rule (if it is available to them)?
Is there really a steep decline in the capabilities of older pilots?

I would expect that many pilots continue to fly, so I wonder whether it makes sense for Lufthansa to risk full confrontation. Also, if the reasoning of the union is right, it would be prudent for airlines to retire older pilots before they are a safety risk.


texts: What is the definition of “airport boundary”?

texts: While flying in to KBTR in a helicopter, I called tower and stated “10 west, landing south ramp with information Mike”. They responded “proceed to the airport boundary”. When I was closer I got the landing clearance to the ramp. Does the phraseology “airport boundary” have a specific meaning, or is it simply in lieu of a pattern entry instruction. My local controllers typically give a reporting instruction like “continue inbound, report 1 west”


texts: If an airplane touches down short of the runway, and doesn't reach it, is it still a runway excursion?

texts:
In light of the two recent incidents where aircraft landed roughly 1000 ft short of their intended runways, Air Canada AC-624 at Halifax and Asiana OZ-162 at Hiroshima, I started thinking the definitions used when labeling them.

At least in the first case, the airline labeled it a runway excursion. Given that the airplane never actually exited the runway (it touched down short and slid onto the runway), I'm a little confused, what is the definition of a runway excursion? If an aircraft never actually comes in contact with the runway, is it still a runway excursion? At what point does it simply become an off airport landing?


texts: Certification of Aircraft Phone/Tablet Mounts/Holders

texts:
I would like to know, whether it is required for such items to be certified for application on genaral and/or commercial aircraft:

https://www.rammount.com/part/RAM-B-166-MP1U

https://mgfproducts.com/products/sport-mount-flex-suction?variant=10434660040819

In what countries is it necessary?
Is it compulsory or not for them to be certified?

I would be gratuful for any help!)


texts: How does the Bombardier CSeries compare to existing single-aisle jet-liners?

texts:
With news breaking in that Airbus will acquire a large part of Bombardier's CSeries program, I'm curious, just how much better are the new planes from Bombardier compared to single aisle planes like the 737 and 320 series?

Aircraft manufacturers drop superficial numbers in their press announcements like, "10% more fuel efficient", etc. It would be great to hear some more technical differences / flying characteristics etc.


texts: Why isn't the last known position of a black box continuously available?

texts: I have read that some GPS satellites receive this data. Where is that information recorded? Why would it not be used? Inmarsat covers all but the polar regions, why don't the airlines use that system to transmit and track aircraft location data? I don't think that cost would exclude this, as a crash is hugely expensive, especially counting downstream costs (search and recovery, collateral damage, etc.).http://www.inmarsat.com/about-us/our-satellites/our-coverage/


texts: Was it possible to land a Boeing 707 with 300 feet cloud ceiling in the 70s?

texts:
In the movie Airplane! (1980), the main characters had to land a Boeing 707 in Chicago airport in low visibility. The dialog says the pilot "should be able to see the runway at 300 feet".

Given the ground equipment and flight instruments of that era, is it possible to land a Boeing 707 in such condition? For example, did they have ILS? Or did they at least have VOR-DME approach that would allow the pilot to adjust the descend rate?


texts: What is the difference between a tail slide and a whip stall?

texts:
Can someone tell me what the difference is between a tail slide and a whip stall?

Whip stalls are prohibited as far as I know in the C152 Aerobat but watching a video of a whip stall it looks exactly the same as a tail slide. The thing is that my aerobatic instructor taught me how to tail slide and I distinctly remember him telling me to make sure that I held the elevator neutral or it could snap off or be damaged.


texts: Does an aircraft equipment suffix denote how many VOR radios are installed?

texts:
I'm studying IFR. Does an aircraft equipment suffix specify if and how many VOR radios are installed?

I'm guessing that the suffix is used by ATC to know if they can give you an RNAV or a an approach that requires DME, so maybe the number of VOR radios is irrelevant? Or maybe ATC assumes that you have a certain number of VOR radios installed?


texts: Are sudden turns and descents a standard emergency procedure?

texts:
First, I'm not looking for speculation on an accident, I just want to know if pilots are trained to make certain maneuvers in response to an emergency.

In reading about the jet that just went down in Egypt, the story stated

  "It turned 90 degrees left and then a 360 degree turn toward the right, dropping from 38,000 to 15,000 feet and then it was lost at about 10,000 feet," Kammenos added.

Assuming the report is accurate, are those maneuvers a standard procedure of some kind? Are pilots trained to maneuver like that in an emergency? If so, in what type of emergency would those maneuvers be useful?


texts: Checklists before take off - how often must they be performed?

texts:
Friday I was on a plane from MXP to Prague, should have been a 737-400, and the take off was preceded by something I'm not sure what it was: probably a pre-flight checklist, but it's the first time I see something like this:

The plane got pushed back by a tractor from ramps to apron - at least, I think it was the apron- and turned (still by the tractor) in the right direction for the taxiway
Engines thrust was increased and decreased a few times, keeping them at "high" levels for a bit
Control surfaces were checked as usual

I'm used to pilots checking control's surfaces either while still at ramps or on the taxiway while waiting for their turn to take off, or just at the beginning of the runway, but never seen anything different and never seen "testing" the engines that way, and it got me wondered about check list frequencies.

Was that routine some kind of checklist? And if so, is there a specific regulation about how often it must be performed? (and, by the way...I know that it's possibile to load fuel even with passenger on board, but...testing engines with plane full loaded? Isn't it a bit too dangerous?)


texts: How much water pressure can flight recorders withstand?

texts:
How deep can black boxes go under water and how much pressure can they withstand while under water before they get crushed?

I'm a layman in terms of aviation, so if it's not too much to ask, can you answer as easily understandable as you can?


texts: How does a long inlet affect a jet engine's performance?

texts:
How, for example, would the long inlet of the tail-engine on an MD-11 or an L-1011 affect its thrust production/performance, if at all?

(Source)

I am not well versed in fluid dynamics, so any insight on this would be helpful. I wouldn't be surprised if the effect of the aforementioned distance is negligible, as the airflow would not seem to be disrupted. Nonetheless, this piques my curiosity.


texts: Do fly-by-wire flight controls in airliners provide artificial feel?

texts:
Mechanical and hydro-mechanical flight control systems (cables, pushrods, hydraulics) all offer pilots some form of feedback – direct or, in the case of hydraulics, artificial – as the aircraft maneuvers and forces are applied to the controls.  I know that early FBW, like that in the F-16 prototypes, used a rigid system that often allowed pilots to over-control the aircraft.

Do fly-by-wire-equipped airliners, like their non-FBW siblings, use an artificial feel system to provide control feedback?


texts: How are the "medical communication" headset sockets on some airliners used?

texts:
I was recently on a flight during which a passenger had a medical emergency.  The passenger vomited and was reportedly unconscious.

The aircraft was either a Boeing 737-700 or 737-800.  I'm pretty sure it was the 800.  It had pretty blue lighting on the interior ceiling, including oval illuminated cutaways.

Located above one row of seats were two ports marked "Medical Communications" (or something like that).

During the emergency, one of the flight attendants connected a wired headset to these ports in order to communicate with others.

With whom was he likely speaking?

As an aside, the system was poorly designed.  One ports was black and the other gray; both ports otherwise looked identical and were the same size; the colors of the headphone connectors did not match the ports.  Both ports were required to make it functional.  The flight attendant had to try multiple times to get the correct wires into the correct ports.  I had to help the flight attendant get it connected properly.  Such a simple and important issue to fix.

Bonus question: Given that the multiple ports did not appear to be for redundancy, why was such a time-critical system not designed with a single port?


texts: Is it possible to split a NOTAM in two messages in case it is too long to fit in a single message?

texts: Would it be in accordance with ICAO norms to issue two different NOTAMs with the same year, series and number regarding the same subject and informing //PART 1 OF 2 PARTS// and //PART 2 OF 2 PARTS// in the NOTAMs bodies to inform that they are parts of a single NOTAM?


texts: Why does a 3D wing's CL keep increasing even after 50° AOA in XFLR5?

texts:
Can you please tell why my 3D wing in XFLR5 keeps increasing it's lift even after 50 degree AOA, while it's 2D profile stalls after about 10 degrees ?

More details on simulation setup:

Airspeed is 15 m/s (Re is about 20000-25000)
Wing chord length is 3 cm
Wing span is 12 cm
Wing is straight
Airfoil is symmetric (NACA-0009)


texts: By just going off the public information about a flight and what one knows about an aircraft, is it possible to construct a differ version of a flight recorder's data well enough to fool investigators?


texts: Why does the aspect ratio of a wing become less important at supersonic speeds?

texts:
My understanding is that an increase in the aspect ratio (AR) of a supersonic wing won't increase the efficiency like it would for a subsonic wing.

If the subsonic induced drag is:
$C_{D_i} = (C_L^2)/(\pi\times AR\times \epsilon)$

And the supersonic lift wave drag for slender bodies* is:
$C_{DWL} = 2\times \frac{C_L^2}{\pi\times AR}$

They're both proportional to $\frac{1}{AR}$ so why is the aspect ratio considered insignificant at supersonic speeds? ------> It seems like I'm missing something here.

*Does this term only apply things like fuselages and nacelles and not wings? If so, what does it mean for it to have an aspect ratio?

Peter Kampf please help


texts: Do airliners have integrated ladders that lead right into the cockpit?

texts: I was watching World War Z and when they were bailing out of Israel, a bunch of armed troops held up a Belarus Ariways Airbus A310 right on the runway.  The pilots dropped a ladder out from near the front of the plane and our heroes climbed up out of danger and directly into the cockpit.  Is this a real thing or just Plot Device™?


texts: As a quick follow-up question to my earlier one about the retail cost of chocks, which wheel(s) typically get the chocks on a GA tricycle-gear plane? Do you buy one roped pair for the nose wheel (make sure your chocks are away before starting up), or two pair for the main gear, or all three (I doubt this, especially on a small plane)?


texts: Did old propeller aircraft begin takeoff off-center to counter p-factor?

texts:
I have tried to ask this in chat and I have been invited to ask a full fledged question here.

Is it true that an old (say about between the two world wars) take-off technique, to compensate for the p-factor experienced at high throttle settings, was to put the aircraft misaligned to the runway and let the p-factor align the aircraft to the center-line?

Example: take an aircraft with a p-factor that makes it yaw to the left, the pilot would have placed the aircraft on the left side of the center-line, with the nose to the right (so, looking at the center-line).


texts: I know that gull wings are shaped how they are for maximum help with a decrease in induced drag and increase in lift, but how do they do it? This is my homework!!!


texts: Are ground crews at danger for radiation from WX radar?

texts:
I am under the impression that the radiation from a weather radar on the nose/wing of aircraft can cause enough radiation to render ground workers sterile/cause cellular damage if the pilot forgets to turn off the radar.

I know most pilots follow a checklist and probably turn it off...but what if one didn't turn it off and a person was marshalling the plane in standing close to the nose of the aircraft?


texts: What is the security policy for getting into a Control Tower in the US?

texts:
Are there any regulations the FAA has ruled to get into a Control Tower? Do people need any special kind of security clearance? Are there forbidden items or other special rules?

I'd also want to know if there's a way for non-pilots (your average civilian Joe) to get into a Control Tower.


texts: Do airline dispatchers pre-block seats for weight and balance on large wide body aircraft?

texts:
I was reading a Oman Air flight review and one of the bits intrigued me:

  I had earlier used ExpertFlyer to monitor both how busy the flight
  would be and the seat map. I selected a window seat when I checked in
  and noticed there were plenty of empty seats around me. On the day of
  the flight, I noticed the two seats next to me were showing as
  blocked, which I assumed was part of a weight and balance exercise.

This review is for a wide body aircraft (Boeing 787 Dreamliner) and I am just wondering if Dispatchers ever block seats for weight and balance like the review writer refers to.

I mean I have often seen large blocks of seats not available for selection sometimes in the online interface but I always assumed this was for commercial reasons and not technical. In smaller flights I have seen passengers being moved around for weight and balance but is this also done in the large wide body aircraft?

Does anyone know?


texts: How did this plane get into this position and orientation?

texts:
taken from https://www.google.com/maps/@-33.9418465,151.174248,945m/data=!3m1!1e3

A) Landing from the east, some crosswind and touchdown off center?
B) Taking off from the east, some crosswind "
C) Landed from the south, for some reason turning left onto runway 27R, heading to international terminal "Global Exchange"?


texts: Why do aircraft on a junk yard have blind windows (e.g. German "Landshut")?

texts:
Today I saw a picture of the “Landshut” (named after a German city, pronounced lund's hoot, not Land shut). The aircraft was hijacked in 1977 and now rusts at the airport of Fortaleza (Brazil) since 2008. German enthusiasts wanted to transfer the plane back to Germany as it somehow and sadly became part of German history, and the German government intends to do so as well.

(http://hessenschau.de/panorama/landshut-104~_t-1488105510615_v-16to9.jpg)
(Source)
I noticed the windows are blind. In an answer to an other question here I can also see a “retired” plane and Peter K. mentions the blind windows in a comment. This gave me the impression that all “retired” planes have blind windows.
Do the windows get blind simply because the planes are left on their own for years and wind, sun, etc. make them blind or are they made blind on purpose? If so, which purpose?

Addendum
After reading the good answers, I reviewed the video I already linked. This screenshot:

(Source: tagesthemen from Feb 23, 2017, 22:15h (German TV news magazine))
shows the cabin of the “Landshut” and it's clearly visible that the interior is removed and the windows are blanked from the inside and covered with grey foil. I just wanted to share this image.


texts: How do I determine the engine thrust required to give a specific climb rate?

texts:
New pilot here and I am playing around with a flight simulator game for the B737-800. I need some help understanding where/how one can find out if one has enough engine thrust (%N1) to meet a required climb gradient in feet per minute, not in degrees.

If an airport has a SID that requires, let's say, 1100 feet per minute climb how do I know that the thrust setting (%N1) that I get from the OPT program is enough to give me that 1100 feet per minute when I takeoff? Where do I find that information? Is it in the OPT or is it in performance manuals and, if so, which performance manual? Please explain it in simple terms and with references. Thank you.


texts: Can reverse-thrust be used to push back from the gate?

texts: Crazy idea, I know.  But instead of pushing back a passenger plane using a vehicle connected to the front wheel, what if I turn on the reverse-thrust and rev up the engine?  My logic is if it can slow down the plane during the landing, it can certainly roll the plane from a dead stop having it go backwards to clear the gate.  Would that be possible in terms of laws of physics?


texts:
Is there something like an ignition key for planes?
Or could one "just enter" and fly away if they could?


texts: What are the requirements for a 'complex' airplane?

texts:
Requirements for 'complex' airplane seem to vary between regulators and between pilots, so let's have this settled once and for all.

What is the definition of a 'complex' airplane as defined by FAA and EASA?


texts: What are the advantages and disadvantages of ruddervators?

texts: Can someone clearly explain the advantages and disadvantages of ruddervators? I cannot find the answer anywhere else.


texts:
New sources such as Seattle Times and Aviation Week provide a pretty good overlay of the MCAS function on B737 MAX. However, I'm unclear as to the issue that MCAS is attempting to fix. From what I can gather, the larger nacelle led to a shortening of the pylon height, leading to altered aerodynamics at the wing/pylon/nacelle junction. At high AOA, this leads to a higher pitch-up moment than on the NG (dispelling other popular theories, it has nothing to do with the thrust line or nacelle CG).

In Seattle Times, it talks about shock formation at the junction, indicating that this is not a low Mach problem. However, transonic regime is usually not limited by stall but by deterrent buffet. Can someone with the knowledge clarify? If it is a stall issue, is it a lack of stall identification (lack of distinct pitch down) or is the aircraft experiencing a pitch-up without MCAS?