Question for B737NG rated pilots. [1]
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Question for B737NG rated pilots. [1]
Hi everyone,
from what I know, if Hydraulic system A leaks and fails, half of the flight spoilers dont work, Nose steering dont work, etc... because there is no fluid there to move them.
My question is:
Let say engine #1 fails and system A is working normally, engine driven pump is therefore inop but AC motor driven pump continue to operate, does the flight spoilers, nose wheel steering, autopilot A etc...still function?
the flow capacity of AC MDP is comparatively lower than the EDP, so I was wondering if the system functions would be afffected.
Thank you in advance
from what I know, if Hydraulic system A leaks and fails, half of the flight spoilers dont work, Nose steering dont work, etc... because there is no fluid there to move them.
My question is:
Let say engine #1 fails and system A is working normally, engine driven pump is therefore inop but AC motor driven pump continue to operate, does the flight spoilers, nose wheel steering, autopilot A etc...still function?
the flow capacity of AC MDP is comparatively lower than the EDP, so I was wondering if the system functions would be afffected.
Thank you in advance
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Oh, they all work, just a tad slower. The QRH for example will tell you that you can expect asymmetric thrust reverser deployment during landing, the left one in your example will take considerably longer to deploy. The landing gear also takes long to retract, thats why there is the Landing Gear Transfer Unit that uses System B fluid and pressure to raise the gear in case of a failure of engine one during takeoff and the initial climb.
Oh, and I am assuming ENG 1 LOW PRESS, nothing else.
Oh, and I am assuming ENG 1 LOW PRESS, nothing else.
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Also I think you'll find that the 737NG FCOM volume 2 states (correctly) that, with a high service demand on that hydraulic system (with the EDP inop), the 'low pressure trip' for the A autopilot may occur momentarily, dropping out the autopilot, but can be immediately re-engaged.
EW73
EW73
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thank you STBYRUD.
I guess the purpose of Landing gear transfer unit and the PTU is to speed up the retraction of gear and the extension of flaps/slats respectively, when system A & B are slow respectivaly. yes?
StudenATP
I guess the purpose of Landing gear transfer unit and the PTU is to speed up the retraction of gear and the extension of flaps/slats respectively, when system A & B are slow respectivaly. yes?
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Basically - the landing gear is operated by system A only, and because a failure of engine 1 would also remove the output of the engine driven pump it would take too long to raise the gear.
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In any case, as previously mentioned, its pretty unlikely that it will disengage due to low pressure, and even if it does you can reengage it right after. It might happen if you rip out the flight spoilers during descent, thats a pretty significant load on the hydraulic system.
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Originally Posted by excrab
Maybe because they dispatched with autopilot B u/s, in accordance with the MEL.
BOAC,
Sorry if I ruffled your feathers. At the three 737 operators I have flown for it was SOP for the captain to engage autopilot A and F/O to engage autopilot B.
Student ATP commented that auto pilot A droppping out was not cool, and you responded to it by asking him why he would be using autopilot A. That was nothing to do with post number 1. I was answering your question with a perfectly reasonable answer. Alternatively he could be a captain training on a new type in which case using autopilot A would be perfectly normal.
Now two reasonable answers to your post, which was actually totally irrelevent to the original question.
Sorry if I ruffled your feathers. At the three 737 operators I have flown for it was SOP for the captain to engage autopilot A and F/O to engage autopilot B.
Student ATP commented that auto pilot A droppping out was not cool, and you responded to it by asking him why he would be using autopilot A. That was nothing to do with post number 1. I was answering your question with a perfectly reasonable answer. Alternatively he could be a captain training on a new type in which case using autopilot A would be perfectly normal.
Now two reasonable answers to your post, which was actually totally irrelevent to the original question.
