Questions tagged [fly-by-wire]

A technology which moves control surfaces by processing pilot input via software.

Filter by
Sorted by
Tagged with
35
votes
14answers
12k views

Why do passenger jets accept input that will cause the aircraft to perform dangerous maneuvers it was not designed for?

Examples: A bank angle > 45 degrees is considered an “upset,” putting the plane in a position that can lead to a loss of control. A pitch > 20 degrees can possibly be dangerous and cause the ...
20
votes
2answers
9k views

How are fly-by-wire airliners controlled in case of complete electrical failure?

In this comment, it is postulated that even fly-by-wire aircraft (Airbus) are demonstrated to fly without any electrical systems. All Airbus aircraft are demonstrated controllable with complete ...
22
votes
1answer
8k views

How does the Airbus flight computer's voting system work?

From what I've read about Airbus planes is that their fly-by-wire system works by having three different flight control computers calculate what the plane should be doing and then vote on all the ...
7
votes
1answer
835 views

Are there any fly-by-wire airliners with negative or near-neutral pitch stability?

Are any modern commercial airliners with fly-by-wire flight control systems designed with negative or near-neutral pitch stability so that they can take advantage of the capability of such systems to ...
15
votes
2answers
4k views

Which CPUs and programming languages are used in new airliner flight control systems?

Are the new systems of today built with the same CPUs and programming languages and development software as those of 20 or more years ago? By new I mean that these systems are currently being ...
29
votes
6answers
5k views

Why aren't there simplified fly-by-wire helicopter controls?

I was discussing helicopter control with relatives over the holidays, particularly regarding how difficult it is to fly one and how changing any control requires adjusting the other two main controls. ...
4
votes
1answer
6k views

How does auto-trim work on fly-by-wire aircraft?

As I understand, you trim to reduce the effort needed to maintain the stick in the right position. Thus, you may reach steady flight before moving the trimming wheel. In fly-by-wire aircraft (to fix ...
13
votes
2answers
1k views

How are Airbus pilots trained for using the mechanical backup control systems?

The A320 and friends have mechanical-only control capability (manual pitch trim + rudder pedals) for cases of total fly-by-wire computer or electrical failure. Obviously, this would be covered in ...
35
votes
6answers
8k views

Why can't the A320's computer-imposed limits be overridden?

Under the investigation section of US Airways Flight 1549, it is noted that [The pilot] asserted that insufficient credit was given to the A320's fly-by-wire design, by which the pilot uses a side-...
34
votes
1answer
6k views

Why is it not recommended to hold the nose up on the A320 after touchdown?

I was recently told by a trainer in my airline that on the A320 if we hold the nose up after main gear touchdown then the flight control laws logic will memorise that pitch attitude after 5 seconds ...
29
votes
3answers
4k views

What kind of delay does the A320's fly-by-wire system add?

More precisely, I am wondering if there is any kind of data on how long it takes between moving the sidestick and observing a reaction on the ailerons or elevator. I know that the physical control ...
21
votes
3answers
3k views

Could fly-by-wire protect against a takeoff tail strike?

If the takeoff weight is underestimated, rotation will be done too early and may result in a case of tail strike. One example of such mistake is a 747-400 (F-HLOV) in 2006 (case 8 in this study). The ...
13
votes
1answer
1k views

Is the A380 ailerons' kinematic modified in alternate law?

I was looking at a video of a A380 display that led me to the "valse des ailerons". This strange ailerons behaviour is available in normal law, but what happen when some fly-by-wire features are not ...
1
vote
2answers
5k views

What does stick fixed and stick free longitudinal stability mean in simple terms?

What is the significance of stick fixed and stick free terms in aircrafts with mechanical control and modern fly-by-wire control?
16
votes
8answers
5k views

Would a wireless fly by wire system be practical?

Given that most modern aircraft are controlled using the fly by wire system, what is the likelihood or the drawbacks of transmitting those fly by wire instructions from the cockpit and or cockpit ...
20
votes
1answer
3k views

Why do flaperons 'move down then up' on takeoff roll on a 787?

The flaperons on the 787 go through certain motions once the TO/GA is pressed. I've always seen it when the 787 is viewed from behind on takeoff. The motions are completely symmetrical, i.e., not ...
12
votes
2answers
2k views

Is A380's center of gravity really too far back?

I have searched and even studied plans from Airbus itself, but I was not able to confirm the following and would like to ask if the information I have is correct. TLDR version so you don't have to ...
5
votes
1answer
1k views

Does the 787 gust alleviation system make a more comfortable ride or for a more stable aircraft?

The 787 active gust alleviation system, similar to the system used on the B-2 bomber, improves ride quality during turbulence. Ride quality in a B2 bomber means a more stable weapons platform. Ride ...
4
votes
2answers
2k views

What exactly happened with the Flight Computers on XL Airways Germany Flight 888T?

I recently saw a documentation about XL Airways Germany Flight 888T. This made some questions rising in my mind: Two AOA-Sensors failed (freezed) simultaneously. From Wikipedia: Two out of three ...
13
votes
3answers
5k views

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

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 ...
12
votes
1answer
3k views

What are the “channels” on the A320 Rudder Travel Limit Unit?

The KNKT's final report on last year's Air Indonesia QZ-8501 crash repeatedly mentions that the faulty solder joint on the Flight Augmentation Computer (FAC) caused an open circuit on "both channel A ...
6
votes
1answer
3k views

Why don't the A380 and A350 have trim wheels?

(wikimedia.org) A350 thrust levers without the flanking trim wheels. Why don't the Airbus A380 and A350 have trim wheels? On the other fly-by-wire Airbus aircraft the trim wheels are there for ...