Utility bus..fuel pump 744
Thread Starter
Joined: Nov 2004
Posts: 72
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From: Australia
Utility bus..fuel pump 744
Okay can't be bothered looking up the manual...er I mean I can't find it in the manual...but why does the no 2 FWD fuel pump fail when one of the utility buses is switched off? (747-400) Any ideas? Just curious.
Joined: Feb 2000
Posts: 1,995
Likes: 512
From: UK
If you are asking why it happens, it's because it's fed from the No 2 galley bus which is one of the first items to be shed when load shedding is required. If you're asking why it's fed from the galley bus .... well, that's one for the guy who designed the electrial system!!
Note that the 'old chestnut' 400 question of "what indications are there of electrical load shedding?" is usually answered as "None", meaning no ELCU messages, becausethey're inhibited. Of course, the correct answer is that if it goes deep enough, you'll get various fuel pump messages starting with FUEL PUMP 3 FWD, then FUEL OVRD 2 FWD etc.
Note that the 'old chestnut' 400 question of "what indications are there of electrical load shedding?" is usually answered as "None", meaning no ELCU messages, becausethey're inhibited. Of course, the correct answer is that if it goes deep enough, you'll get various fuel pump messages starting with FUEL PUMP 3 FWD, then FUEL OVRD 2 FWD etc.
