The ADP's must be in Auto. The FCU R will signal Hyd Sys 1 & FCU L will signal Hyd Sys 4 through there associated HYDIM card. On GE and P & W aircraft the pumps will run continously in flight with flaps extended. On the ground they will only run until flap position matches that of flap handle. As you say there is no FCU redundancy for this feature. If either FCU L or R is inop the flightcrew would have to select ADP 1 or 4 to On manually during landing/take-off. Not sure about the RR equipped aircraft, can you help us out here Spannersatcx?
The B747-200 has none of the above and just uses EDP low presssure (2600psi) as a signal to run the ADP in Auto, it runs for 10 to 12 seconds afgter 2800psi is attained.
As for the Body Gear Steering, we tow with the ADP at Auto so would run all the time.
Hope this is of some help.
Last edited by Denzil; 1st Jun 2002 at 12:45.