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View Full Version : B777 Why is so quiet while turning R demand pump on?


sm165019117
10th Oct 2023, 11:00
i found when we need to pressurize the hydraulic system before pushback, after turning on the R demand pump to auto, there will be quiet in cockpit for a while ( sounds like fans stop working), i am confused...
any logic within the demand pump, fans and noise in that situation. thanks a lot!!!!

applecrumble
10th Oct 2023, 17:57
i found when we need to pressurize the hydraulic system before pushback, after turning on the R demand pump to auto, there will be quiet in cockpit for a while ( sounds like fans stop working), i am confused...
any logic within the demand pump, fans and noise in that situation. thanks a lot!!!!

ELMS load shedding while the demand pump comes up to speed.

sm165019117
13th Oct 2023, 06:22
ELMS load shedding while the demand pump comes up to speed.
Thanks a lot, you are right. I checked the electric synoptic during turning the R demand pump to auto, there was a load shed showed. it seems that galley doesn't work or stop working at that moment.