FMS and FMC

[md-100]

Which is the difference between a FMS and a FMC?

[belowMDA]

To begin the FMC is the Flight Management Computer. The FMS is the Flight Management System. The FMC is just a computer that calculates various things chiefly the navigation of the aircraft and is displayed on the CDU(control display unit). The FMC uses inputs from the FMS to do this. The FMS incorporates things such as the IRS the Air Data Computers and the FMC. Don't have my books infront of me so this is the best I can come up with.

[QNH1013]

The FMS (Flight Management System) is made up of 4 parts.

1) FMC (Flight Management Computer)
2) Autopilot and Flight Director System
3) IRS's
4) Autothrottle System

Each part can work collectively or independantly.
FMS is the term used when combing all these components to work together to make up the Flight Management System as they are all the systems used to obtain performance data and to fly and navigate the aircraft by automation.

So the Flight Management Computer (FMC) is just a part of the whole FMS.

Hope that helps and I describe as per 737 aircraft. Airbus use differnet terminology (FMGS) though I think the logic is the same.

[Capt Pit Bull]

As an approximate analogy, think of your PC.

The FMC is the base unit.

The FMS is the whole thing including - all the input/output/control stuff. e.g. your printer, connection to the internet, monitor, keyboard etc etc.

CPB

[Intruder]

The FMS (Flight Management System) is made up of 4 parts.

Plus:

5) Control Display Units
6) GPS
7) VOR/DME/LOC