Boeing 767 Stabilizer Trim and Pitch Enhancement System
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Boeing 767 Stabilizer Trim and Pitch Enhancement System
Hello,
I have a few quick questions about B-767 stabilizer trim and PES.
In the event that normal L and C hydraulic pressure is lost, I understand that the Pitch Enhancement System automatically begins operating. It uses R system hydraulic fluid to drive a motor that in turn powers a hydraulic pump which utilizes trapped L system hydraulic fluid to to operate the stabilizer at 1/4 normal rate and is controlled only by the yoke electric trim switches (alternate and autopilot trim inop).
My questions are: if there is a loss of all 3 HYD system pressures, L, C, & R, is it correct to say that no stabilizer pitch trim is available? Is there also no stabilizer trim available if the L&C fail but the trapped L system fluid somehow leaks or is otherwise unavailable? Also, in the above two scenarios, do any of the three stabilizer trim methods (yoke, alternate, autopilot) do anything if activated?
Thank you.
I have a few quick questions about B-767 stabilizer trim and PES.
In the event that normal L and C hydraulic pressure is lost, I understand that the Pitch Enhancement System automatically begins operating. It uses R system hydraulic fluid to drive a motor that in turn powers a hydraulic pump which utilizes trapped L system hydraulic fluid to to operate the stabilizer at 1/4 normal rate and is controlled only by the yoke electric trim switches (alternate and autopilot trim inop).
My questions are: if there is a loss of all 3 HYD system pressures, L, C, & R, is it correct to say that no stabilizer pitch trim is available? Is there also no stabilizer trim available if the L&C fail but the trapped L system fluid somehow leaks or is otherwise unavailable? Also, in the above two scenarios, do any of the three stabilizer trim methods (yoke, alternate, autopilot) do anything if activated?
Thank you.
Join Date: Jan 2012
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You are correct: if the L & C fail, and the L loses all of its fluid, then the PES won't have anything to work with; you will not have pitch trim.
If you completely lose L, C, & R hydraulic pressure... then you have much bigger problems than just pitch trim. Like primary flight controls.
If you completely lose L, C, & R hydraulic pressure... then you have much bigger problems than just pitch trim. Like primary flight controls.
