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Questions tagged [redundancy]

For questions about the use of multiple similar components to keep a single failure from being catastrophic.

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10 votes
6 answers
9k views

Why are many parts of an airliner required to be triplicated, but not the "parts" most likely to malfunction (i.e., the pilots)?

Many components of airliners are installed with three redundant systems to reduce the risk of equipment failure causing accidents. However, there are only two of the "components" most likely ...
Someone's user avatar
  • 7,097
0 votes
2 answers
183 views

How to identify the faulty GPS-INS in dual redundant installation?

If we have two GPS-INS sensors on an aircraft, how can we decide which one is giving the correct measurement? I know that for sensors, we can vote, but what if we have two sensors? Please give me a ...
ahmad khansari's user avatar
8 votes
4 answers
2k views

Are there wool threads for displaying angle of attack?

Like there is a wool thread on a glider's canopy for showing relative wind on yaw axis. Are there or have there been a wool thread as a long term mean of showing angle of attack? For instance placed ...
user avatar
5 votes
2 answers
958 views

Do aircraft have backup systems to trim when they don't have trim wheels?

What happens if the motor that trims the elevator of an airplane fails and there are no trim wheels in the cockpit (like in the Boeing 747). Is there a backup system or hidden trim wheels?
manarinian's user avatar
2 votes
1 answer
222 views

What is the Correct Procedure to Test Portable Backup Airband Radio (US)?

I recently obtained a portable air band radio for use as a backup radio in flight. As this is a backup, it isn't much use without being tested. I'm trying to determine the proper way to test the ...
AJ Henderson's user avatar
6 votes
2 answers
527 views

Have attitude indicators ever had triple failure in a commercial aircraft?

I'm wondering about couple of well known crashes (mainly AF447 and AirAsia 8501) and thinking: is there any case where triple redundant attitude sensor failure has ever occurred? In those accidents it ...
Mikko Rantalainen's user avatar
0 votes
0 answers
223 views

How is the control surface configuration of predator/reaper for redundancy system?

In commercial aircraft like Airbus or Boeing, there are several control surfaces that work in the same function such as for roll control capability, the control surfaces are aileron and spoiler. Also ...
Zahi Azmi's user avatar
1 vote
1 answer
424 views

How many Angle of Attack sensor vanes should a commercial passenger airliner have? [closed]

The ill fated MAX of recent news had 2 angle of attack vanes, with the MCAS computer picking the worst one. It seems a "software patch" may not be the only improvement option available. Sensible ...
Robert DiGiovanni's user avatar
26 votes
5 answers
10k views

What is the rationale for single engine military aircraft?

In aeronautics, redundancy is of primary concern. Having at least two engines is common for civilian aircraft. I expect the military to have at least the same level of redundancy. Moreover military ...
Manu H's user avatar
  • 16.5k
0 votes
1 answer
240 views

How reliable is keeping flight maps on an iPad in the cockpit? [duplicate]

Are flight maps no longer kept on a shelf in the cockpit as a back up in case the iPads malfunction? One story that I managed to research highlighted that this was under debate to rely only on a ...
user avatar
1 vote
4 answers
372 views

Why don't nonrigid airships have multiple gas cells?

Nonrigid airships (blimps) differ from rigids and most semirigids in having the entire envelope form a single large gas chamber, rather than dividing the lifting gas among several redundant gas cells. ...
Vikki's user avatar
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2 votes
1 answer
321 views

What kind of flight-control redundancy does the Tu-204 have?

The Russian Tupolev Tu-204 and variants are reported to be digital fly-by-wire. Are they quadruplex redundant? Do they have manual or analog back-up systems?
KGN's user avatar
  • 21
18 votes
4 answers
4k views

Why is not every airplane equipped with 3 angle-of-attack sensors?

For critical systems, redundancy is built into the system. It is common knowledge among designers/architects to have three different inputs so in case one is faulty, input from the remaining two can ...
Regmi's user avatar
  • 925
2 votes
2 answers
602 views

Why don't aircraft carriers have multiple sets of arresting wires?

On this answer to this question regarding the merits of angled flightdecks on aircraft carriers, @JanHudec makes this interesting observation: You don't really have "two flight decks". The ...
Vikki's user avatar
  • 28.4k
0 votes
1 answer
339 views

Why does the DHC-6 have only one set of elevator cables?

Air Moorea Flight 1121 crashed because its up-elevator cable broke, allowing the elevator to blow to its faired position and thus be unavailable to counteract the pitch-down moment caused by the flaps ...
Vikki's user avatar
  • 28.4k
3 votes
3 answers
415 views

Can horizontal stabilizer trim be worked independently (each side)?

I notice most jetliners have a big trim wheel on each side of the center console. This wheel is black with white stripes, and notably turns on its own via the autopilot. Two large trim wheels: And ...
Harper - Reinstate Monica's user avatar
6 votes
1 answer
11k views

What is the difference between redundancy and fault tolerance?

What is the difference between redundancy and fault tolerance in the context of aviation ?
summerrain's user avatar
  • 3,434
54 votes
4 answers
13k views

How dissimilar are redundant flight control computers?

Facts On Airbus aircraft there are computers to secure the flight envelope, or to move the control surfaces. FADECs totally control the engines. Computers take decisions in place of the pilots, or ...
mins's user avatar
  • 74.5k
13 votes
5 answers
3k views

What alternative methods are there for controlling a plane when flight control surfaces have failed?

I saw a TV show once about Japan Airlines flight 123, in which the aft pressure bulkhead ruptured, disabling hydraulics and ripping off the vertical stabiliser. So the flight crashed after some time ...
Craig McQueen's user avatar