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31 votes
Accepted

Which trigonometric algorithm does an FMS use to determine distance between waypoints?

Short answer Aeronautical data (fixes, waypoints, navaids, instrument procedures) are delivered to aircraft operators and avionics manufacturers referenced to the WGS-84 ellipsoid. To make is ...
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26 votes
Accepted

Why is air traffic control done manually by humans?

Having it explained to me briefly what exactly the tower does that cannot be handled by such a system would probably enlighten me somewhat. Fair warning, that's my job you're trying to replace with a ...
17 votes
Accepted

How do pilots set the exact amount of thrust needed for a reduced power takeoff?

The EMB-145 used a combination of FADEC settings and the thrust levers to select the desired thrust and to signify the need for additional thrust. The thrust levers had a detent that selected "100%"...
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17 votes

Why are true headings followed above 73N in the northern hemisphere, whereas in the southern hemisphere the change is made at 60S?

Earth's magnetic field is not symmetric north to south. In particular, the magnetic declination can get significantly larger at a given southern latitude than it does at the corresponding northern ...
12 votes

Does the Fokker 70/100 Flight Management Computer really contain the ability to play Pong?

The 'clip' is obviously a fake. Standards for avionics software development and testing are rigorous, with development of flight critical software being done by separate (independent) groups and ...
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8 votes
Accepted

What type of computers are in a flight system?

Historically, avionics manufacturers have used off-the-shelf processors on custom circuit cards. Processor selection has been based on getting a reliable processor (established history) at a ...
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7 votes
Accepted

Can SID/STAR have shortened names?

According to the Jeppeson chart legend[pdf] those are database identifiers. I'm presuming that's what would show on a menu in the FMS.
  • 27.8k
7 votes

How do pilots set the exact amount of thrust needed for a reduced power takeoff?

caseys answer nicely describes the procedure for the Embraer 145. Since you specifically mentioned the Boeing 737 and Airbus A320, here is how it works for these aircraft: Boeing 737 All Boeing ...
  • 47.3k
7 votes
Accepted

What is the relationship between "automatic flight control system AFCS", "autopilot", "flight director" and "flight management system FMS"?

Since you are studying maintenance, I would suggest you obtain a copy of ATA iSpec 2200, Information Standards for Aviation Maintenance ATA Standard Numbering System. Most large aircraft ...
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7 votes
Accepted

What are these "F,S,O" characteristic speeds?

F speed is the minimum speed at which flaps should be retracted from CONF 3 or 2 to CONF 1+F. S speed is the minimum slats retraction speed, i.e. the minimum speed at which a clean configuration ...
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7 votes

Why are the character keys on the Flight Management Computer in alphabetical order?

"we are all used to the QWERTY or QWERTZ layout..." or AZERTY. But which one? Universally there is no one standard, so whichever of these 3 (and others) is chosen, it will be wrong for some users. So ...
  • 4,497
7 votes
Accepted

Is the 737's autopilot part of the FMS or is it a separate entity?

In Boeing terminology, the FMS, Flight Management System, is comprised of: Flight Management Computer System (FMCS, which is essentially two FMC's, at least on the 737... other jets may have one FMC, ...
  • 42.8k
6 votes

How do pilots set the exact amount of thrust needed for a reduced power takeoff?

Usually power output for a jet engine is gauged from its low pressure turbine speed. In turbofans, this corresponds to the fan speed, displayed as N1. In general, the derated takeoff thrust will be ...
6 votes

Does the Fokker 70/100 Flight Management Computer really contain the ability to play Pong?

It's probably fake but there's no reason why it couldn't be in and why it couldn't be approved like that. An (The!) acceptable means of compliance to FAR/CS 23/25.1309 is DO-178. Airborne software is ...
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6 votes
Accepted

What is the ALT INTV on the 737's autopilot?

From the FCOMv2 4.10.10 (emphasis mine): Altitude Intervention (ALT INTV) Switch [Option - With speed and altitude intervention] Allows manual deletion of next FMC altitude constraint via ...
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6 votes
Accepted

What do the different types of approach abbreviations used on the A320 MCDU exactly mean?

CI = course to intercept CF = course to fix FI = fix to intercept CD = course to DME FD = fix to DME These are AIRINC 424 leg types. You can find more information on them here
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5 votes

What is the FMS Bridge Visual 28R approach at SFO?

Source: stilllearningtofly.org The FMS bridge visual is an RNAV charted visual approach to 28R that keeps aircraft offset to the north of the 28R localizer until they’re near the San Mateo bridge. ...
  • 81
5 votes
Accepted

Is it possible to disengage only one axis of a two-axis autopilot?

Some autopilots found on advanced aircraft can be engaged on selected axis only, for example Boeing 737, 747-200 & MD-11. There are three autopilot indicators on the Boeing autopilots: auto ...
  • 39.3k
5 votes

Is the flight management system software independent from the hardware?

If you are thinking of the analog of installing windows or linux on a given physical personal computer then the answer is more or less no. Not because its not possible but more because thats not how ...
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5 votes
Accepted

How did KAL 007 get so far off course?

Chapter 4 of Degani's Taming HAL covers some of the details of this disaster, and is on a NASA site The Crash of Korean Air Lines Flight 007 It details some of the interface deficiencies in the ...
  • 5,177
4 votes

Is the 737's autopilot part of the FMS or is it a separate entity?

They are separate systems, but the autopilot can be set to get guidance from the FMC (Flight Management Computer). For lateral navigation, the autopilot can be set to follow a heading, or a VOR/LOC. ...
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