[AVIATION RELATED] Circuit of a FMC (Flight Management Computer)

Thread Starter

mytree123

Joined Oct 6, 2023
2
Hello everyone!
I am currently planning a presentation for uni and sadly can't find any circuit drawings online for a FMC. I am a newbie when it comes to circuits so I would find it very helpful if anyone could send me a circuit drawing of a FMC and maybe even describe a bit on how e.g. the insertion of data by the pilots theoreticaly works circuit wise.

What I did find on the internet was that the FMC consists of a few PCB depending on the type. Is that correct?
Thank you in advance and have a nice day!

Cheers
Niels
 

Alec_t

Joined Sep 17, 2013
14,335
Welcome to AAC!
The FMC is a complex thing, so I doubt you will find any circuit drawings for one online. It would require inputs and outputs from/to hundreds, if not thousands, of sensors, switches, motors and control devices. In addition, critical systems are triplicated for safety, requiring three computers whose outputs are compared in a 'voting system'.
I guess the best you could hope for would be a block diagram.
Pilot input is via keyboards, switches and position encoders.
 

Thread Starter

mytree123

Joined Oct 6, 2023
2
Welcome to AAC!
The FMC is a complex thing, so I doubt you will find any circuit drawings for one online. It would require inputs and outputs from/to hundreds, if not thousands, of sensors, switches, motors and control devices. In addition, critical systems are triplicated for safety, requiring three computers whose outputs are compared in a 'voting system'.
I guess the best you could hope for would be a block diagram.
Pilot input is via keyboards, switches and position encoders.
Hey!
Thank you for the swift reply, this is the info I was looking for. Would you happen to have a block diagram for the fmc? or maybe a circuit drawing for one certain action within the fmc?
Thank again, really appreciate it!
 

WBahn

Joined Mar 31, 2012
30,082
Hey!
Thank you for the swift reply, this is the info I was looking for. Would you happen to have a block diagram for the fmc? or maybe a circuit drawing for one certain action within the fmc?
Thank again, really appreciate it!
You need to do some legwork.

Identify some companies that make these devices and start contacting them. Explain to them that you are a university student and what you are being asked to do and then ask who you can talk to that might help you. You may have to talk to several people before getting the right person. Do not expect them to put in a lot of time, but you have a good shot at finding someone that is willing to speak (or trade e-mails) with you and probably send you some information to base your talk on.

When I was taking a thermodynamics course back in 1990, I wanted to do a presentation on how the bootstrap turbine in an F-15's air conditioning system was used to improve system performance. All I knew about it was that the turbine drove a compressor that compressed the air, which then went through a heat exchanger and, from there, was used to drive the very turbine that was running the compressor. So I called McDonnel Douglas (no Internet or e-mail back then -- not in any meaningful sense) and got bounced around a few places, but ended up talking to the chief engineer on the F-15 program who spent about an hour talking to me and then mailed me system diagrams, some blue prints, and a couple of industry papers on the system.
 

Jon Chandler

Joined Jun 12, 2008
1,055
If you approach professionals for some help/guidance, I suggest you first do some substantial homework, outlining the system as you think it should do.

Break down the functions.

Break down what these functions need –
> I/O, some kind of display and keyboard
> sensors to measure what?
> actuators to operate what?

If you think it though and make an detailed outline that shows some effort and thought, you might get a response other than a hung-up phone or ignored email.
 
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