Questions tagged [flight-controls]

The methods or mechanisms used to control an aircraft's movement in roll, pitch, and yaw.

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1answer
56 views

How much force is produced by control surfaces?

Context: For some context, I'm a game developer and I'm building a flight sim game. My goal is to have realistic -- not arcade -- physics. The game is in Unity. Unity handles the actual application ...
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1answer
292 views

How does the F-16 side stick convert pilot input to an electrical signal?

In What is the motivation behind designing a control stick that does not move? the F-16's control stick is discussed. What is the method that is used to sense the pilot's input to the stick and ...
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What is the maximal acceptable delay between pilot's input and flight control surface actuation?

While I was watching a cockpit video of an A330 landing in which the pilot was frenetically moving its sidestick, I wander what was the reaction time of this flight by wire system. Indeed, the time ...
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What is the motivation behind designing a control stick that does not move?

According to Wikipedia (and various other online sources), the control stick on the F-16 does not move. The input values are determined by the amount of force acting on the stick, rather than the ...
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2answers
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What does it mean to move a single flight control to its full deflection?

It is the speed below which you can move a single flight control one time, to its full deflection, for one axis of airplane rotation only This is part of the explanation of maneuvering speed. What ...
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2answers
527 views

Are thrust levers synchronized by default when pushed/pulled? [duplicate]

When I watched this video about the last flight of Juergen "J.R." Raps from SFO to FRA in an A380 (before his retirement) I noticed he lines up or synchronizes the four thrust levers as shown between ...
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1answer
121 views

What is the difference between autopilot and autoflight?

Can you please give me some explanations about autopilot and autoflight system?
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70 views

How did the Caproni Ca.60 electrical communication system work?

On the wikipedia page for the Ca.60 it says: The two nacelles also housed a cockpit for one flight engineer each, who controlled the power output of the engines in response to the orders given by ...
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1answer
164 views

What are the maximum possible stabilizer and elevator deflections for the A320?

For research purposes I would like to know the maximum deflection angles (in both positive and negative direction) of the A320-200's stabilizer and elevator. I am trying to analyse what flight ...
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1answer
124 views

Do Airbus avionics give good deadstick landing outcomes? [closed]

We have recently had a second good outcome, in Russia, of a no power landing of an Airbus aircraft. The first was the "miracle on the Hudson". It appears to me that the avionics of this aircraft are ...
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What sort of sensors are used for sensing the positions of the control surfaces for the ECAM F/CTL page on Airbus aircraft?

During the pre-flight flight-controls-check how does the ECAM F/CTL page report on the actual positions of the control surfaces? What sort of sensors are these? Is it a proximity sensor? This is ...
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Could sidesticks be linked?

A sidestick is spring-loaded to the centre position. If there were servos under the stick, connected to the other side stick, so instead of being spring-loaded to centre, it was spring-loaded to the ...
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1answer
324 views

What happens to thrust and drag in a straight and level flight?

Straight and level flight means when an aircraft is flying at a constant speed without changing its attitude. Its lift is equal to the weight of the aircraft. It is flying at a constant altitude. Then ...
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1answer
179 views

Why are the spoilers used as the backup controls instead of ailerons on the Boeing 777?

While reading this question, I ran across an interesting unanswered comment. Why did Boeing choose to use some of the spoilers as mechanical backup controls rather than the ailerons?
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1answer
385 views

What flight controls should be used to counter asymmetric yaw?

How should the autopilot or pilot handle asymmetric yaw, as with one failed engine on a multi-engine turboprop whose engines are not on the centerline? Should one apply roll control or rudder control?
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3answers
267 views

Why do some helicopters have such complicated flight control mixers?

Image source Some helicopters have a very complicated set-up that mixes flight control inputs to many or all of the swashplate actuators, like in the picture above for the S-76. Why are all the ...
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1answer
166 views

On coaxial helicopters, how exactly does the yaw mechanism work?

This question asks how coaxial helicopters achieve yaw. The accepted answer correctly states that this is done by increasing pitch on one rotor while decreasing pitch on the other rotor, which leaves ...
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4answers
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Why would a pilot use ailerons for countering asymmetric thrust in mid-flight?

A inexperienced 747-400 pilot used ailerons for counteracting asymmetric thrust in 1998 aboard United Airlines Flight 863 (YouTube recreation). Why would an airline pilot do such a mistake? Why would ...
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11answers
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Why force the nose of 737 Max down in the first place?

Can someone here explain a pretty basic question that I have had ever since this controversy came to light? I don't understand why any aircraft manufacturer, engineer, software developer, would make ...
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2answers
118 views

What is the future for auto-pilots? [closed]

What is going to change with auto-pilots on commercial aircraft in the next decade or so? Will airlines allow an auto-pilot to control an aircraft when it lands and takes off? Will we start using
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5answers
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Why is the UH-60 tail rotor canted?

The Sikorsky UH-60 (S-70) has a tail rotor that is canted 20 degrees upwards. Why is that? Picture source
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2answers
309 views

Why did Boeing keep using yokes while Airbus moved on to sidestick?

The first Airbus had yokes but they changed to the sidesticks after a while But Boeing is still stuck with yokes even with 777-300ER decades later. The sole purpose of the yokes are seemingly for the ...
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2answers
217 views

Why are the flaperons on the 787 located so far in-board?

Why are the flaperons positioned in between the outboard and inboard flaps (see 2nd picture)? Why not have them located as far outboard as possible to achieve maximum roll authority? I would think the ...
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6answers
4k views

What's the minimum number of sensors for a hobby GPS waypoint-following UAV?

I would like to develop my own guidance, navigation and control (GN&C) flight software on a Raspberry Pi, for a small hobby fixed-wing UAV. From a physical standpoint, what is the minimum set of ...
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1answer
132 views

Does the MU-2 have a crossover airspeed?

Airplanes generally have a crossover airspeed (a minimum airspeed below which directional control of the airplane cannot be maintained in the event of a rudder hardover). This is because, as airspeed ...
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1answer
43 views

How to calculate variation of Z force with elevator deflection (Zδe) in Nelson for pitching dynamics?

I have been trying to model the pitching dynamics of a General Aircraft (Nelson : Flight Stability and Control) but during the modelling, I find that I need to use the ...
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1answer
371 views

Did the Douglas SBD Dauntless have a second set of controls?

In the book Never Call me a Hero, the author mentions that there were controls in the rear seat of the Douglas SBD Dauntless. However, I don't recall ever hearing this before, though I know the TBD ...
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1answer
3k views

What happens to Cessna electric flaps that are moving when power is lost?

On final in a C182T you move the flap control arm from 20 to FULL, and when halfway there, the breaker pops (or BUS1 fails, a wire falls off, etc.) Does the flap stay where it is, slide back to 20°, ...
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2answers
288 views

B777- In emergency mechanical back up how does the flight controls manage engine failure

In case of engine failure above the ocean with multiple electrical failures and after having exhausted the batteries the fly by wire mechanical backup with available hydraulics if left with the THS ...
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2answers
165 views

Are modern commercial airliners flyable without operational computer systems?

Do modern commercial airliners have manual control capability to fly and land if electric power remains on but all computer systems and digital communication/guidance fails?
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3answers
4k views

How strong someone should be in order to fly without “power steering”?

Planes these days use fly by wire systems while older ones had a mix of hydraulics with electronic assistance like the MD-11 (And maybe 737-800?). But what would happen if you lost the electronic ...
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1answer
322 views

Why isn't a human required to confirm visually that flight controls are moving?

On this A380 flight after pushback and engine start and before taxi, Capt Juergen Raps and and Sr FO Harald Tschira rely solely on their FID to check flight controls. On a regular flight without ...
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What failure modes did Airbus seek to eliminate or mitigate when they changed the design of the A310/A300-600's rudder travel limiter?

In the NTSB report on the crash of American Airlines Flight 587, it is mentioned (in the context of the changes between the A300-B2/B4's rudder system, on the one hand, and the A310/A300-600's rudder ...
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138 views

Would a long pole help stablize a jet pack?

Jet packs are classically worn like a book-bag on the back. Would it be more stable if the exhaust ports were separated? Would the jet pack be easier to control if the turbines were at the ends of a ...
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4answers
2k views

What could be the cause of an uncommanded roll at high speed?

I have a problem with a T-38. There is uncommanded roll to the left when the aircraft flies at 250 knots. But as the aircraft speed goes up around 500 knots, the uncommanded roll is now to the right. ...
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1answer
197 views

How will the alpha lock function intervene when performing a takeoff at heavy weights on the A320?

In the FCTM for the A320 family of aircraft's under the SOP Takeoff chapter it is mentioned that the alpha lock function can intervene when performing a takeoff at heavy weights. Can someone please ...
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1answer
187 views

Why is the speedbrakes rate of retraction 25 seconds when used at speeds greater than 315 knots/.75 Mach on the A320?

While I was routinely reading the FCOM normal procedures I came across a note with regard to the speedbrakes retraction time going up to 25 seconds when we use them at speeds at or over 315 knots / ....
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1answer
151 views

What is the input range of common fly-by-wire controls?

What's the range that typical fly-by-wire controls (let's take A320 and B777 as examples) allow inputs in? The A320 controls in the y-axis of the side stick (forward/backward axis) the g load - what'...
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2answers
187 views

What is the THS deflection speed?

Let's restrict this question to best sellers airliners (A320 and B737). On this aircrafts, the THS is used for pitch trim. The speed requirements may not be has intense as for elevator as it control ...
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6answers
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Why not use the yoke to control yaw, as well as pitch and roll?

(Inspired by this question about rudder hand control on joystick-equipped aircraft.) Most civilian fixed-wing aircraft (post-1987 Airbus airliners being the primary exceptions) use a yoke (...
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1answer
373 views

What is the Space Shuttle's command law?

The Space Shuttle was fly-by-wire. In today's fly-by-wire systems, the command law commands either the load factor and the roll rate (e.g., A320's normal law), or the surface control deflection (e.g., ...
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1answer
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Why did AF447 never return to normal law?

Air France Flight 447 degraded from normal law to alternate-2B law when its pitot tubes were temporarily filled with ice crystals, resulting in a loss of airspeed data. As a consequence of being in ...
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2answers
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Does load factor affect roll rate?

To be clear I am referring to a given aircraft at a given weight, speed, attitude, etc everything else the same except one is at say 0.5g and the other at 2.5g will there be a difference in roll rate ...
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0answers
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Do aircraft use some kind of stability control to keep the aircraft on the runway during landing? [duplicate]

Modern automobiles use an electronic system called ESP to keep the car on track in slippery situations. Do modern jet liners have a similar system to aid the pilot in keeping the aircraft on the ...
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0answers
87 views

Would throttle steering of a forward-swept-winged aircraft be possible?

Fortunately (or perhaps unfortunately, given the number of crashes that had to occur for us to figure it out), the use of throttle manipulation to control an airliner with disabled primary flight ...
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4answers
566 views

Why would Boeing's MCAS be preferable to a modified Feel and Centering Unit?

According to some sources, the purpose of MCAS on Boeing's 737 MAX variants is to increase the back-force needed to further raise the nose when flying manually at high angles of attack, in order to ...
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2answers
563 views

Why can't the 737 MAX's horizontal stabilizer autotrim be cut out by control yoke inputs?

According to this article, a horizontal stabilizer runaway on the 737 MAX, unlike with all other 737s, cannot be countered with yoke inputs: Older 737s had another way of addressing certain ...
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1answer
670 views

Why does the flight controls check come before arming the autobrake on the A320?

As per SOP on the A320 we first perform the flight controls check and then arm the autobrake to max. What is the reason behind this?
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1answer
250 views

How do you disable plane AI when the plane goes crazy? [duplicate]

This came to my mind when I learned 737 MAX crash was caused by the AOA indicators giving faulty info to the AI which crashed the plane. So how do you completely disable the flight computer when it ...
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3answers
491 views

What does rudder input control in normal law in an A320?

I understand form documentation that in normal law, pedal input is not necessary to keep coordinated flight. It is merely said that using the pedals is not necessary. Later in the documentation it is ...