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View Full Version : 3 VERY EASY questions HYD system 737 classic


W.SHIRRA
14th Aug 2003, 20:04
Hi all! I'd like to ask 3 questions about the hydraulis system:

1] The "B" tank is damaged and has lost all of its fluid.
The FLT CONTROL switch is positioned to STBY RUD.
The using units return the STBY fluid to the "B" reservoir, but
this fluid goes lost.
The consequence could be the total loss of STBY fluid in case
of extensive usage.
Is it for this reason that the Leading Edga Devices can be
extended but not retracted by the STBY system?


2] Despatch with Antiskid inoperative.
Is it necessary to manually brake in order to stop the wheels
from spinning before raising the gear?


3] Total loss of system "A" fluid after lift off, but with no engine
failure.
Since the NOSE WHEEL STEERING switch (as installed) acts on
the Landing Gear Transfer Valve, would it be possible to use
it in order to raise the gear with system "B" pressure?

Thanks a lot, Gentlemen, for your inputs.

Regards
W.Shirra

Rananim
14th Aug 2003, 20:19
1)About 1 US gallon is saved for PTU operation(autoslats) and that is all.Nothing to do with Stby sys.

2)NO

3)NO

avioniker
14th Aug 2003, 23:26
Here's a very simple answer to your #1

http://www.b737.org.uk/hydraulics.htm

The using units return the fluid to the resivoir from whence it came. B to B and Standby to Standby. (Okay spoilers, brakes, reversers are exceptions - quit hollering, I'm simplifying)
The standby resivoir is serviced by the B system resivoir at the 72% level but it is a stand-alone system when used and the fluid doesn' t intermingle with the other systems. (Please see parenthetical statement above)
The leading edge devices, when actuated by the standby system are a relatively low drag device without the penalties in speed that the trailing edge flaps cause. If they are extended by the standby system you're looking for a place to land because things have really gotten bad. You won't be needing to retract them in the near future.