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flapsforty
3rd Jan 2002, 21:00
After landing yesterday the captn of the flight sighed and said they'd had 4 FMC failures.

The lads had to run to make their next flight, so I never did get a chance to ask him what that was all about.

If FMC means flight management computer (does it??) what does 4 failures mean?
Anyone care to explain this to a simple trolley dolley? <img src="wink.gif" border="0">

static
3rd Jan 2002, 21:43
Hi!
Good to see Jenny was holding up her end of the bargain....
An FMC failure is not a big thing. Until about 3 years ago we could dispatch a 737 without an FMC. It`s not a vital part. I still don`t know why it`s a no-go now. Probably has someting to do with B-RNAV.
An FMC is basically a navigation computer with some peformance optimisation extra`s.
In the old days we used to fly from radiobeacon to radiobeacon until we arrived at the destination. Nowadays, with the help from the FMC we can fly from waypoint to waypoint, without needing radiobeacons. The FMC calculates the position of the aircraft and the course needed to arrive at the next waypoint. It does this with the help of a lot of techno-gizmo`s I won`t bore you with.
So if one fails, you simply fall back on the old way of navigating: tune the next beacon and follow the needle. Or in the absence of beacons, you ask the air traffic controller for a radar-heading (i.e. he tells you where to go).

So, it`s really not a big thing, just means some extra work for the guys up front. And for maintenance once on the ground.

CU

static