Hydrolic transfer B737NG
In response to VD8 his question, altough a bit late (only just read it now), maybe this is what you are looking for:
When accepting the aircraft and finding the hydraulic quantity indication over maximum (106% on the NG) in e.g. System A:
To transfer from system A to B:
ELEC A pump ON
ParkBrake SET
ELEC A pump OFF (pressure drop)
ELEC B pump ON
ParkBrake RELEASE
ELEC B pump OFF (pressure drop)
repeat as needed (usually 3-4 times suffice)
Although this was an overfull SYS B, an overfilled hydraulic system has at least once led to an evacuation after vacating the runway, putting the flaps to up, causing hydraulic vapor to enter the cabin (check valve failure). Bad press and very sick customers.
As correctly pointed out, quantity indications vary with configuration and with diff temperatures, and fluid does seem to travel from system to system.
Good thread!
Last edited by Jetdriver; 7th Nov 2013 at 12:11.