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 ...
- 71k
27
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 ...
- 36.2k
18
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%"...
- 35.2k
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 ...
- 1,722
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 ...
- 19.4k
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 ...
- 54.3k
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.
- 28.4k
7
votes
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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 ...
- 19.4k
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 ...
- 8,070
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 ...
- 4,608
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, ...
- 49.8k
7
votes
Accepted
What does flight ID mean here in the picture? It stated in brackets for Performance
Since you tagged diamond-da40, I assume this is about the G1000 avionics as installed in the DA40. The manual for that G1000 unit is available on the Garmin website. According to the manual, the ...
- 54.3k
7
votes
Accepted
Why did autopilot switch to CWS P on a LNAV/VNAV approach, and why didn't it reduce descent rate to comply with CDU alts when VNAV was re-engaged?
That behavior, VNAV switching off and going into ALT HOLD or even CWS PITCH, can happen when the VNAV "gets lost" and no longer can draw a vertical path from where it is to its End-of-...
- 49.8k
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 ...
- 72.9k
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 ...
- 54.3k
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
- 4,837
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. ...
- 91
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 ...
- 39.7k
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 ...
- 100k
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 ...
- 5,551
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. ...
- 71.8k
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