Originally Posted by
Doc Holliday
Does the Q400 not have a standby hydraulic pump that works of the batteries? so if the engine driven pump goes u/s there is no back up from a DC pump? why could they not switch on the batteries (or plug in an GPU) then turn on the standby pumps and charge up the system? just interested as I have never flown the dash.
The Q400 does not have a DC pump. There is an AC pump in the no1 system called the SPU (standby power unit) and there is a PTU that pressurises the no 2 system from no 1.
The normal ground power is DC on the nose but AC can be connected on the right nacelle.The usual way to top up the parking brake is with the hand pump in the right nacelle.
If the maintenance guys had just done a "Line Check" (75hrs or 10 days I think) then the brake pressure would have been depleted to check the N2 charge in the accumulator (500psi). The hand pump needs to be used to top up the pressure again.