Questions tagged [avionics]

Avionics is applied electronics to aviation. Radars, radios, instruments, dashboards, they all belong to this category.

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51
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3answers
20k views

Why is Python used on aircraft although it may not be certifiable?

I recently had a discussion with people who were active in the aviation industry and told me that one of the main languages/tools they use is Python. On the other hand I have always known that people ...
50
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3answers
10k 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 ...
47
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4answers
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What programming languages are used for equipment onboard aircraft?

Generally speaking, What programming language is used in aviation for (ATC Radio, Radar, ILS, Auto-pilot and on-board avionics)? Is there a standard enforced by ICAO? Does every plane manufacturer ...
40
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12answers
30k views

Why don't all commercial aircraft transmit GPS data in real time?

It seems strange that trucks and taxis can be set up to transmit GPS data in real time but aircraft cannot. Wouldn't this be a useful function and feasible to implement?
34
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1answer
7k views

How does WiFi work on an aircraft?

I've noticed that when a WiFi system is set up on an aircraft, a small bulbous structure is added. What does it contain and how does this WiFi system work?
33
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3answers
2k views

Could the CVR and FDR record to the cloud?

Another enthusiast question. I watch a lot of the National Geographic Channel's "Air Crash Investigation", for better or worse, and it seems accident investigators make tremendous use of the Cockpit ...
32
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2answers
7k views

What exactly did this mechanic sabotage on the American Airlines 737, and how dangerous was it?

An American Airlines mechanic sabotaged a 737 in Miami An American Airlines mechanic accused of sabotaging a navigation system on a flight with 150 people aboard at Miami International Airport was ...
32
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3answers
30k views

Are fighter jets designed to be so inherently unstable that a human can't fly one unassisted?

I'm told that in order to be more maneuverable fighter jets are designed in a way that makes them impossible for a human to control without the help of a flight computer. Is this actually true? ...
32
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3answers
5k views

Are there common standards for aviation graphical user interfaces?

I'm searching for graphical user interface in aviation guidelines. Yet I miss the correct terms and I don't really know where to start. Let's take an example: what's the meaning of the green ...
31
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2answers
5k views

What are these boxes built into the tails of some fighters?

In looking at European-designed fighters of the 4th and 4.5th generation, I keep seeing a common design feature; a box-like structure built into the tail, often in the top half or third. Some examples:...
29
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3answers
7k views

Why are on-board computers allowed to change controls without notifying the pilots?

Recently we've had the 737-MAX debacle, where it increasingly appears that the MAX on-board MCAS system repeatedly would issue nose-down events, leading to the Lion Air crash, and possibly another ...
29
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2answers
51k views

How does an alpha (AoA) vane work?

The alpha vane (also called AoA vane) is an external probe used to measure the angle of attack. I have been trying to understand how exactly it works, but I can't find any clear explanation or ...
29
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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 ...
28
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6answers
16k views

Is it possible for a modern commercial airliner to stop being tracked without substantial mechanical failure?

I was speaking to someone about the MH370 incident, and they suggested that a hijacker could turn off the device that sends the plane's current position, resulting in the appearance of a catastrophic ...
28
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3answers
3k views

What's the UX in modern airliner avionics for diversion choices, and does it integrate to autopilot?

This question mentions a flight that had to divert, in that case to Iqaluit (YFB). I was wondering: in modern large airliners, what is the user interface like when diverting? How is the case of "what ...
23
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5answers
6k views

Do safety-critical avionics systems run Linux?

I have heard diverse things about this. Some people claim that running Linux on safety-critical avionics systems is a very bad idea. On the other hand some people (who are rather unfamiliar with ...
23
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3answers
2k views

Why are FDRs and CVRs still two separate physical devices?

Given the histories of flight data recorders and cockpit voice recorders, I somewhat understand their origins as two separate physical devices. Given their separate tracks of development, regulatory ...
22
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3answers
2k views

What is ADS-B and who needs it?

I read that ADS-B is required by the year 2020. What does this mean? What is ADS-B used for, and who needs it?
22
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1answer
5k views

Do aircraft manufacturers produce their own black boxes?

Do the manufacturers who build airplanes use their own "black boxes" in the planes, or are there companies whose sole purpose is to develop black boxes? For example, in 2010 in the Airblue Flight 202 ...
22
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5answers
4k views

Could a Personal Locator Beacon or EPIRB carried by a passenger aid in locating a downed airliner?

There've been a lot of questions lately about tracking aircraft, and after a conversation with a friend of a friend I started wondering: Could a PLB or EPIRB carried by a passenger or crew member aid ...
20
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4answers
11k views

Like transponders, can flight recorders be turned off?

I never knew much about airplanes before the tragic incident of Malaysia 370. I have been spending a lot of time on Twitter reading various articles and investigations; in one of the articles I read, ...
19
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12answers
6k views

Why are critical flight computers redundant?

At least in airliners, the truly critical computers are redundant. Typically three identical copies of the autopilot computers run in parallel and compare results; if one computer disagrees with the ...
19
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3answers
4k views

Do planes have odometers?

I'm curious to know if planes have distance counters similar to the ones in cars indicating how many kilometres/miles the plane has flown since being put in service.
19
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1answer
13k views

What exactly distinguishes a beacon light from a strobe light?

Different sources seem to have different opinions: Wikipedia: Aircraft warning lights: These lights include landing lights, red or white flashing beacons, wingtip strobes, and wingtip navigation ...
18
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2answers
23k views

How does TACAN work?

How does the Tactical Air Navigation (TACAN) system work? How is it different from the VHF Omnidirectional Range (VOR) system? Please explain in the simplest possible way.
17
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2answers
3k views

How does an aircraft derive winds aloft on its own?

The G1000 has a feature where it can put up a winds aloft arrow/speed in the PFD. I've been sort of wondering how exactly this is determined. My guess is that the aircraft (or the G1000) knows your ...
16
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6answers
5k views

Is it possible to accurately measure airspeed without pitot tube?

This is a follow-up to my previous question: How does this IMU work and how to convert its output into meaningful information? for which many people asserted that I need a pitot tube and a static ...
16
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1answer
2k views

Why is it hard to see G1000 with sunglasses?

I got checked out in the G1000 172 at my flight school just so I could schedule to fly when the two steam gauge 172s were booked. I'm very impressed by the G1000, but I can't wear sunglasses when I ...
16
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1answer
3k views

Why do helicopters and airplanes use different headset plugs?

If the headsets and microphones for general aviation have the same impedance for helicopters and airplanes, then why do they have different connectors on them? Is it simply to make more money from ...
16
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2answers
4k views

When should a transponder be used?

When should a transponder be turned turn on? On the ground? Always in flight? Only when required: during radar service (flight following), above 10,000ft MSL, inside the Mode C Veil, or on IFR flight?...
15
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3answers
2k views

What does “synoptic” mean in avionics?

I came across a mention of a display of "graphical aircraft system synoptics" on this page. I think in context that it means "status display" or "summary page"- the page that shows flap position, ...
15
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3answers
3k views

Why shouldn't you use HF radio while refueling?

FCOM limitations for many aircraft state: DO NOT USE HF RADIO WHILE REFUELING Why is this? I have heard from people that it's because most of the big airliners have a 'notch' antenna for HF; it's ...
15
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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 ...
14
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2answers
11k views

How precise are altimeters?

How precise and how accurate are typical altimeters these days? That is, if two planes are flying (side-by-side, very near each other), and both altimeters show the same Flight Level, what is the ...
14
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1answer
855 views

Did the contemporaries of the F-14 also have automatic swing wings?

The F-14's Central Air Data Computer was a innovative design, using microprocessors for its implementation. This computer was used to control the swing wings of the F-14. How did the contemporary ...
13
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1answer
871 views

What coming changes might render current IFR equipment worthless in the foreseeable future?

I'm shopping for my first aircraft. I have found a very well cared for 172 that is VFR. I also found an IFR-certified 172 that is higher time and cosmetically is showing its age. I inquired about ...
13
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3answers
1k views

How are avionics updates delivered?

I'm idly curious to know what type of physical storage medium (e.g. is it a "mini-CD", USB key, a little hard drive, maybe a tape) is used for delivering avionics updates, for an as-recent-as-possible ...
13
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2answers
962 views

How is an on ground lightning strike test conducted?

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. ...
12
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1answer
5k views

How is varying modulation depth achieved by localizer ground transmitters?

An approaching aircraft's navigation receiver uses the difference in depth of modulation between the 90Hz and 150Hz signals which are amplitude modulated onto an RF carrier (on a channel between ...
12
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3answers
3k views

What's the difference between orientation and position?

In INS (Inertial navigation system) sensors, is there a distinction between the following? Orientation (heading, pitch and roll) Position (latitude, longitude and altitude) Is the orientation ...
12
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2answers
2k views

Are there any accident reports that mention hacked/compromised avionics as a factor?

Does anyone know of any documented examples of airline accidents caused by hacked or otherwise deliberately compromised avionics?
12
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3answers
4k views

What is the history of glass cockpits?

All glass cockpits seem to have the same basic setup for the primary instruments. Altitude tape on the right, air speed tape on the left, turn coordinator on top and an artificial horizon in the ...
12
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2answers
1k views

What do the gyroscopes used in commercial aircraft actually look like?

I pretty much grew up watching Air Crash Investigation and Seconds From Disaster and every other episode had a mention of the aircraft’s gyroscopes, but I always wondered how did FAA rated industrial ...
12
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2answers
1k views

Do military jets' radar jammers block their own radar? And, if not, why not?

Will a noise jammer block the fighter's own radar? If I have understood it, a noise jammer, e.g., a barrage jammer, will emit a noise signal across a wide frequency band. Won't this make it hard to ...
12
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1answer
400 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., ...
12
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1answer
2k views

How do I tell a Garmin 430 not to exit a hold?

Let's say that we're directly west of CATLI and have been cleared direct CATLI for the RNAV approach. We load the approach into ...
12
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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 ...
11
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3answers
1k views

Is VOR identification automated in modern avionics?

Is the VOR identification via audible Morse code automated in modern autopilots / avionics? Or does a pilot in an A380 still sits in there, listens and compares the .-. .. -.. to her charts?
11
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2answers
14k views

What is the difference between CAN and ARINC?

I want to know the difference between CAN and ARINC, I'm confused about their usage. For example, the communication between the cockpit and the controllers is done using ARINC protocols. And the data ...
11
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1answer
2k views

What causes the phase to change in a VOR?

I get the light house analogy, and how the VOR essentially works, although I'm wondering what actually causes this phase shift? As it hits magnetic north the variable and reference signal are in phase,...