BRUspotter From Belgium, joined Jan 2004, 145 posts, RR: 0 Posted (8 years 7 months 3 weeks 4 hours ago) and read 2865 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.
I never think of the future - it comes soon enough.
Nyskymasters From , joined Dec 1969, posts, RR:
Reply 1, posted (8 years 7 months 2 weeks 6 days 15 hours ago) and read 2448 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.
Boeing767mech From United States of America, joined Dec 2000, 1037 posts, RR: 3
Reply 2, posted (8 years 7 months 2 weeks 6 days 5 hours ago) and read 2150 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.