FlyerTalk Forums - View Single Post - Strange "valve-like" sound on 747 before landing

Aug 23, 2011 | 7:13 am

#13

BingBongBoy

FlyerTalk Evangelist

Join Date: Dec 2008

Location: Home: East Mids UK - Work (Base): Accra, Ghana.

Programs: BAEC: Silver - Marriott: Titanium

Posts: 12,086

Quote:

Originally Posted by BApilotinsider

Well I have trained on the 747...

If its in the final 3000 feet for example and it's slightly turbulent with convection currents the pressurization can make the odd noise you describe.
The reason is the cabin has already adjusted to the landing altitude, at LHR it's 82 feet asl. If you pick up an up or down current on your approach, the pressurization will have to vent to maintain that landing altitude.

Hope that helps...

I think that is what I was trying to say... But not quite as well...

It happens on the 767 too? I have heard, what I think is the same noise, often on the 767 when in the cabin preparing for landing.

Reply