Originally Posted by
alcan60283
Silliest thing on an aircraft really. Don't know why they couldn't have just gone with a regulated pump that ran full time instead of the on demand thing they came up with. If you look at the PTU in service, and watch the lines, EVERYTHING moves drastically when it kicks on too. Odd design that thing
Yes you are right, after being sensitized to this sound and knowing its origin it hurts the engineering/physics
part of my brain each time it kicks in ;-)