37
votes
Accepted
Why aren't there simplified fly-by-wire helicopter controls?
Helicopter manufacturers seem to have been slow to adopt fly-by-wire systems. I used to work in the General Dynamics group which designed the fly-by-wire system for the F-16. That was the first ...
- 486
34
votes
Accepted
Would a wireless fly by wire system be practical?
The fly-by-wire is absolutely vital for control of the aircraft, and the three dominating factors here are safety, safety and safety. Weight is not one of them. The fly-by-wire system is triple or ...
- 61.3k
25
votes
Accepted
What kind of delay does the A320's fly-by-wire system add?
Yes there will be a delay, but the delay caused by the control loop is really tiny. I've seen position control loops run successfully and stable at a couple of hundred Hz for simulator motion systems, ...
- 61.3k
25
votes
Accepted
What is the difference between autopilot and fly-by-wire system?
An autopilot can fly the aircraft based on pilot selected modes. The autopilot therefore reduces the pilot's workload by replacing manual inputs via the yoke or sidestick. A fly-by-wire (FBW) system ...
- 54.3k
23
votes
What is the maximal acceptable delay between pilot's input and flight control surface actuation?
Excessive phase lag is a direct contributor to Type I Pilot-Induced Oscillation (PIO). Phase lag comes from:
Rigid body dynamics of the aircraft (e.g. delay between elevator surface and pitch rate ...
- 11k
22
votes
Accepted
How are fly-by-wire airliners controlled in case of complete electrical failure?
For the complete electrical failure in the aircraft, the following systems have to fail:
The onboard power generation system, usually a synchronous generator has to fail in all the engines.
The APU (...
- 100k
21
votes
Accepted
Do pilots use the pedals in flight on planes with a sidestick (Airbus)?
The rudder pedals are not usually used in flight, even with the autopilot off.
The rudder on the Airbus A320 can be controlled via a mechanical connection to the rudder pedals in the flight deck, but ...
- 54.3k
17
votes
What is the difference between autopilot and fly-by-wire system?
Fly-by-wire system removes physical link between cockpit controls and flight control surfaces. To do this, there must be some sort of rule how pilot's input is interpreted and converted into control ...
- 3,250
16
votes
Why can't the A320's computer-imposed limits be overridden?
Computer limits can be overridden on an Airbus as a ‘last resort’, though I have serious doubts that would have helped with the landing on the Hudson incident.
Granted, getting out of Normal Law is ...
- 7,935
14
votes
Accepted
Do Airbus pilots have to practice flying in alternate law?
It appears in both situations that the PF had trouble stabilizing the aircraft roll attitude.
Note that roll control is secondary when recovering from a stall.
Restoring normal pitch and roll, he ...
- 26.3k
13
votes
Would a wireless fly by wire system be practical?
That will be very unlikely simply because wireless is much less reliable by several order of magnitude.
considering the current day an age of terror threats if the encryption (and you will need ...
- 27.4k
13
votes
Are there any fly-by-wire airliners with negative or near-neutral pitch stability?
No.
Modern FBW airliners use less static stability than what the early jets were used to, but stability is still positive. The negative camber at the root airfoil of sweptback horizontal tails might ...
- 230k
13
votes
What kind of delay does the A320's fly-by-wire system add?
I don't have an answer for the timings (I personally don't think that's publicly available information), but I can answer this
is the delay noticeable by pilots?
as I have some direct experience, ...
- 32.4k
13
votes
Accepted
Why did fly-by-wire systems take so long to implement?
A simple answer is that the aircraft control system has ultimate responsibility for survival of the aircraft. If it completely fails, you are as good as dead in most cases. Short of in-flight ...
- 9,013
13
votes
Accepted
How does the Boeing 777's yoke of both the captain and the first officer have synchronized movement?
From the FCOM v2 (9.20.1):
The primary flight control system uses conventional control wheel, column, and
pedal inputs from the pilot to electronically command the flight control surfaces.
The ...
- 54.3k
13
votes
Do pilots use the pedals in flight on planes with a sidestick (Airbus)?
Side stick or no, once airborne, you never touch the rudder pedals in any airliner when flying except during landing where independent rudder inputs are used to keep the airplane lined up during the ...
- 126k
13
votes
Accepted
Under what circumstances does the F-16 and possibly similar fighters deploy leading edge slats?
Technically, F-16 and "similar fighters" have leading edge flaps (LEF) (or droop flaps), rather than slats. The difference is that they don't form a gap between themselves and the main ...
- 9,013
12
votes
Which CPUs and programming languages are used in new airliner flight control systems?
Note: I focused more on changes in aviation hardware and software than what's currently used since the question linked about programming languages is still current for "new" aircraft. I do not wish ...
- 6,725
11
votes
Accepted
How is a fly-by-wire system realized in big planes?
In fact, ARINC 429 is used in the "federated" avionics, this is the "old" system used in many aircraft like A320, B737, ...
Federated avionics require a lot of wires which generates a lot of weight. ...
- 635
11
votes
What is the difference between autopilot and fly-by-wire system?
You have already received a number of excellent answers, and I just want to add something very short and to the point, regarding the question you pose in your title:
What is the difference between ...
- 5,700
10
votes
Why aren't there simplified fly-by-wire helicopter controls?
There are two extremes:
No augmented controls, i.e. most normal aircraft. Pilot controls control surfaces and engines directly.
Heavily augmented controls (left, right, up down shifts exactly like ...
- 33.2k
10
votes
Accepted
How are Airbus pilots trained for using the mechanical backup control systems?
In my particular case:
I probably did 10 minutes of demonstrating mechanical backup during initial type rating
I cannot remember for sure, but it never reappeared in any recurrent sim, and even if I ...
- 7,935
10
votes
Is A380's center of gravity really too far back?
No. Positive lift on the tail does not necessarily mean that the center of gravity needs to be aft of the aerodynamic center of the aircraft. Only when the lift per area of the tail surface is higher ...
- 230k
10
votes
How much computing power is needed to keep commercial and military planes flying?
For commercial airliners: the computing power is set during development and certification of the type. The A320 was developed in the 1980s and still uses Intel 80186 and Motorola 68020 processors. ...
- 61.3k
9
votes
Do Airbus pilots have to practice flying in alternate law?
When I did my initial type rating on the Airbus it was rare to find the aircraft in normal law. The thing is most of the complex failures such as dual hydraulic failures, emergency electrical ...
- 1,943
9
votes
Do Airbus pilots have to practice flying in alternate law?
Air France 477 was in a fully developed stall. In a normal flight attitude. All the way from 40,000 feet to the surface of the ocean. The aircraft was falling like a leaf from a tree, with an angle of ...
- 61.3k
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