Cornish Jack
3rd Aug 2001, 11:44
My aging and rapidly decaying brain cells can't cope with an apparent anomaly in the 400 hydraulic QRH drills.
QRH 1 - "HYD OVHT SYS ( )"
EDP - OFF
Demand pump - AUTO
QRH 2 - "HYD PRESS SYS ( )"
EDP - OFF
Demand pump - ON
Obviously the above are extracts and not the complete drills but the post drill conditions are the same - EDPs switched OFF and, therefore, the aircraft is reliant on the demand pumps to provide hydraulic 'muscle'. Sooooooo... the question is:-
Why does one case have the demand pumps in AUTO and the other (essentially same conditions) have the demand pumps at ON.
The HYDIM logic triggers would provide continuous running for either case, since the demand pump AUTO logic is looking for > 1600 psi from the EDP to switch off the demand pump. So WHY !!!
This is with Boeing at the moment and am awaiting a reply (and have been for several weeks) but would anyone like to hazard an educated guess ? PLEASE!! :confused:
QRH 1 - "HYD OVHT SYS ( )"
EDP - OFF
Demand pump - AUTO
QRH 2 - "HYD PRESS SYS ( )"
EDP - OFF
Demand pump - ON
Obviously the above are extracts and not the complete drills but the post drill conditions are the same - EDPs switched OFF and, therefore, the aircraft is reliant on the demand pumps to provide hydraulic 'muscle'. Sooooooo... the question is:-
Why does one case have the demand pumps in AUTO and the other (essentially same conditions) have the demand pumps at ON.
The HYDIM logic triggers would provide continuous running for either case, since the demand pump AUTO logic is looking for > 1600 psi from the EDP to switch off the demand pump. So WHY !!!
This is with Boeing at the moment and am awaiting a reply (and have been for several weeks) but would anyone like to hazard an educated guess ? PLEASE!! :confused: