Questions tagged [avionics]

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

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33
votes
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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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? ...
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?
47
votes
4answers
23k views

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 ...
28
votes
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 ...
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?
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.
4
votes
1answer
11k views

What's the difference between FMS and FMC?

What's the difference between FMS (Flight management System), and FMC (Flight management computer)? Can the flight management computer be thought of as what's manipulating the input information from ...
29
votes
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 ...
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 ...
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?
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 ...
5
votes
3answers
6k views

How many antennae are there on a typical small aircraft, and how are they connected to the avionics?

As far as i know there are a bunch of antennas on board of a small (EASA CS-23) plane: GPS is for GPS navigation in MHz VHFVOR is for NAV and Glideslope/Localizer ADF is for ADF DME is for DME ...
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 ...
9
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3answers
5k views

What data does ACARS send back to base? Can it be used to track a plane?

An aircraft's Aircraft Communications Addressing and Reporting System uses line of sight HF via ground stations or satellites to communicate with its base station. This system allows for three types ...
12
votes
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 ...
9
votes
2answers
591 views

Why can't flight management systems receive instructions directly from the controller?

If an aircraft's flight management system has auto pilot and auto thrust coupling, and it can make changes to the aircraft speed and direction along the entire route without pilot intervention, then ...
16
votes
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?...
13
votes
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. ...
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 ...
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 ...
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 ...
19
votes
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 ...
16
votes
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 ...
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 ...
7
votes
1answer
11k views

What connector standard is used for aviation headsets?

The typical aviation headset features two cords with connectors that at first glance are identical. One is a standard 1/4" (0.25 inch) stereo audio jack. What kind of connector is the slightly ...
7
votes
1answer
6k views

How does the ADF null positions find where the NDB is?

I understand how it operates for the most part, although I don't understand how the null positioning works. This image below doesn't include the sense antenna that limits it to one null position, ...
7
votes
2answers
1k views

Could a terrorist hack the ILS?

I'm reading all these reasons why consumer electronics can't be on during takeoffs and landings and one specific reference that is made over and over again is the sensitivity of the ILS equipment. I ...
5
votes
2answers
6k views

What is the encoding difference between ARINC 429 BNR and BCD formats?

I think I have an understanding of the differences between the types of ARINC word formats, but would just like to get some input to see if my understanding is correct. In the ARINC 429 specification, ...
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, ...
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 ...
11
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2answers
11k views

How can I tell if a G430 or G1000 has WAAS or not?

Both the GNS430 and G1000 are/were available with and without WAAS, and I believe it's even possible to upgrade a GNS430 to add WAAS support. When I get into an unfamiliar rental aircraft, is there a ...
8
votes
2answers
2k views

What's an estimate for the cost of the cockpit technology on a 747 or 777?

Can anyone share what the percentage cost or dollar costs of cockpit instruments and related software is within a 747 or 777? PS- I'm a physician working in medical safety. Physicians can no longer ...
8
votes
1answer
4k views

Which airplanes are exempt from Europe's 2015 CPDLC (Link 2000+) requirement?

In February 2015, all flights above FL285 in EU airspace are required to have CPDLC/Link 2000+. However, I have been told by an avionics provider that some aircraft types are exempt from the ...
5
votes
1answer
2k views

What type of computers are in a flight system?

I know there are many types of flight computer systems, with varying names and capabilities. I'm more interested in knowing what the computers, themselves, are made of? They certainly are not "off ...
51
votes
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 ...
13
votes
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 ...
11
votes
2answers
3k views

Airbus control architecture - where does the actual autopilot live?

I'd like to ask for confirmation about the A320 (and, generally, Airbus family) control architecture. The book Aircraft Systems provides the following overview of A3XX computing architectures: ...
29
votes
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 ...
7
votes
3answers
819 views

Is it possible to ping ACARS repeatedly and track an aircraft?

This is a followup to What data does ACARS send back to base? Can it be used to track a plane? I had asked this as a part of the earlier question, but it seems to be a large enough issue to be ...
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.
10
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1answer
460 views

How do airliners facilitate in flight calls for mobile phones?

How does an airline facilitate in-flight calls for mobile phones? I would guess that over open water in flight calls are relayed by an on board link to a communications satellite. Such a system ...
9
votes
2answers
24k views

What is the difference between Line-Replaceable Unit (LRU) and Integrated Modular Avionics (IMA)?

I'm studying the Integrated Modular Avionics (IMA) and the Line-Replaceable Unit (LRU), but I don't get the difference.
6
votes
2answers
2k views

Why doesn't civil navigation equipment support TACAN?

Now even handheld aviation radios have GPS, VOR and ILS! I wonder why modern LCD screens with radios and navigation doesn't have TACAN? Is it coded, not useful, not certified or not used anymore? I ...
5
votes
1answer
409 views

Is there any reason to have ADS-B out that is not based on GPS?

The ADS-B system is only as accurate as the location data source it uses. In the US the 2020 ADS-B mandate requires that horizontal location data be from a GPS source with minimum performance ...
5
votes
4answers
3k views

How are pitch angle and pitch rate measured in an airplane?

What equipment or method is used to obtain measurements of the pitch angle (θ) and pitch rate (q) during flight? Edit: I am asking about how the aircraft systems sense these quantities
4
votes
1answer
1k views

Why does Boeing 737 use 2 Inertial Reference Systems (IRS) and GPS?

According to this website the Boeing 737 aircraft use 2 IRS and 2 GPS: IRS L & IRS R. Why? Apparently they are totally independent of each other. Could somebody explain a little bit why they need ...
3
votes
1answer
249 views

What is the behaviour of ILS when there is an unmodulated interfering carrier signal?

Let us assume we have a localizer (identifier I-STK) transmitting at 110.10MHz and a matching glideslope at 334.40MHz. If a device aboard an aircraft tracking the I-STK ILS were to emit an ...
0
votes
2answers
984 views

Will the new Part 23 changes reduce the cost of avionics for existing aircraft?

Will the part 23 changes coming in August help to reduce the cost of IFR GPS avionics? I'm looking to upgrade the IFR avionics in a 1978 Cessna 182.
12
votes
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 ...