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Topic: The 767's Whining Wings
Username: BRUspotter
Posted 2007-04-11 11:00:52 and read 2409 times.

Why do the flaps and wings on the 767 continiue to whine and whirr during the whole slow down after landing? I have noticed it several times but only on this particular plane. Explanations greatly appreciated.

Topic: RE: The 767's Whining Wings
Username: Nyskymasters
Posted 2007-04-11 23:44:14 and read 1992 times.

I just saw your post and I will take a try at answering your question.

I am assuming you are hearing the hydraulics coming alive. Unlike the 757, the 767 's hydraulic systems are arranged differently. The right and left systems are driven by an engine driven pump and an electric pump that is a demand pump. In otherwords, the engine driven pump, which is high volume and high pressure, runs continuously with the engine. However, when a high load system is used then the electric demand pump starts up to assist and backup the engine pump. The brakes are on the right system so perhaps that is what you are hearing.

Same can be said with the center hydraulic system. The flaps are on the center system which, when activated, brings the center Air Driven Pump on line. That causes a lot of noise as well. Now for the spoilers, each panel is powered by one of the hydraulic systems. So, they are causing all demand pumps to activate as well.

Hope this helped.

Topic: RE: The 767's Whining Wings
Username: Boeing767mech
Posted 2007-04-12 10:12:09 and read 1694 times.

You most likely hearing the flap drive motor. The flaps and slats are driven by a hydraulic motor which turns rotary actuators on the flaps and slats. The Drive motor for the flaps in the wheel well so you get alot of noise in that area. Like the ohter person posted the center pumps are in the wheel well and the ADP is on the Left side of the fuselage behind the wing.

Hope this helps
David


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