Question for the QF 747-400 guys
Saw a QF 744 on the bay in HK doing a control check before pushback, is this normal if you have a pushback delay or would it be a problem, no engines running.:confused:
Just of interest it was morning of 24/2 if crew see this. |
G'day bugsquash1,
Unlke the older B747s the B747-400 can pressurise all four hydraulic systems before engine start and complete the control check before pushback. This is standard procedure for QF. There is a combination of engine driven pumps, air driven pumps and electric pumps to pressurise the various systems. Regards, BH. |
Thanks
It just seemed strange to do it before start, but I suppose on the bus we wait for the computers to screw up on start before the control check :E Fly by wire :mad: |
Do you complete a second control check prior to T/O? Or just the one on the bay?
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Just one on the bay
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I don't know why you bother on the bus... who knows what input they will send to the flying controls from one second to the next! :}:}
(FWIW the 767 does the same - preflight procedure is to get a clearance to pressurise the hydraulics and do a control check) Why on the bus do you need to do a brake check when you taxi (like a cessna 172) - is it because you are checking the hydraulics ? Or you are checking the computers are sending a signal to the brakes? |
. . . and what happens if the brake test fails?
Is it a bit like, :ok:if at first you don't succeed, so much for skydiving. |
re, A330
Blueloo
The check is done to ensure there is no residual pressure in the brake system that may cause a dragging brake. . . . and what happens if the brake test fails? If the test fails, ie, you have a dragging brake, you will know pretty much the moment the wheels turn. cheers 'n beers:ok: |
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