window-seat

Could any Airbus pilots (or anorach's) please tell me what the small hatch, located behind and below the rear starboard passenger door (A320 etc) is, as it always appears to be open as the aircraft is taxying out to the runway?

Techman

It is the outflow valve.

Used to regulate cabin pressure.

Always open on ground since aircraft must be depressurized on ground.

window-seat

Cheers Techman!

tva164

Techman

Does it automatically open and shut or is it manually controlled from the f'deck. Didn't see any switch for it so its probably not directly switchable, if you know what I mean. Any action or combination of actions leading to it? Cheers

Old Dog

Many years ago when I flew to China, the Beijing air traffic controller enquired about why was the 'door' wide-open on the left side of my fuselage, while my DC-10 was taxiing out for departure. I asked him which door? He said the small square door about half-meter by half meter on the port side of my fuselage. I think he was referring to the pressurisation dump valve, so I told him this is normal for DC-10, and the door will be automatically closed during the t/o run.

It seems they have never seen a DC-10 before.

AffirmBrest

The Outflow Valve is usually automatically controlled, however it can be manually controlled in the event of problems with the CAB PR SYS - using the switch in the lower right of the overhead panel marked 'CAB V/S', as long as MAN(ual) contol of the cabin pressure has been selected

FLY BY WIRE

Ditching switch also closes Outflow valve, (when not under manual control)- great for Deicing

AffirmBrest

and ditching

FLY BY WIRE

I wouldn't know, I've never tried it