What is the small hole under A320 rear door?
 

Hi all, I flew from LIS to LHR yesterday (BA 501) and I noticed for the first time a small, open 'hatch/door' just underneath the very last rear door on A320's and 19's, I saw 6 aircraft taxiing to the runway with these open. Im quite knowlegeable on aircraft but I must admit I have no idea what these are, can someone answer this?

I apologise in advance if this is achingly obvious.

Thanks!
:ok:

AlexB,

The door you see is part of the pressurisation system for the aircraft.

The valve is scheduled open/closed by the same logic that controls the pressurisation.

Normally open on the ground, it closes after take-off and re-opens on touch-down. It ensures that the cabin pressure is equalised with the amosphere outside to allow door opening etc.

Regards,

Shuttlebus

Thanks very much Shuttlebus, I presumed it was something to do with ventilation.

I presume it is only the case on Airbuses as I have never seen it on the old 757's I used to use on the route :confused: It seemed a bit large, like a maintenance door! hehe anyway thanks for the answer!



:O

Was it an aer lingus 320 by chance??? Could be the door for the little fellers to get out!!! :}

A similar question if I may ..... a Bombardier Challenger lines up ready for takeoff ...... a nice amount of liquid is discharged from below the rear of the fueselage, just before departure ...... what is the liquid? :confused:

It's the pressurisation outflow valve, and yes the 757's have them too - albeit I think it is on the opposite side to the A32X series.

Much appreciated.


Hobie- due to the location of the liquid discharge from the challenger, it could possibly be from the onboard lavatory :confused:

It is definitely not from the lavatory. Lavatory waste is kept on board until removed by the honey cart. But all aircraft have drain masts. These are connected to the galley and lavatory sinks. What you saw was the cabin crew emtying the coffee pot down the sink before take off. A practice which us engineers frown on. We insist it goes down the lavatory, because coffee grounds clog drain lines

ALL large passenger aircraft have Outflow Valves.. Some even have 2!

Here is an excerpt from the A340-200 Maintenance Manual


21-30-00 PB 001 - PRESSURIZATION CONTROL - DESCRIPTION AND OPERATION
1. General

The pressurization control system controls the pressure in the fuselage. It operates fully automatically and has a manual backup. The pressure change rate is controlled to give satisfactory pressure values of safety and comfort for the passengers and crew.
2. System Description

The pressurization control system has the subsequent subsystem:
- pressure control and monitoring.

The pressure control and monitoring system (Ref. 21-31-00) makes sure that the pressure in the fuselage is safe and comfortable for the passengers and crew. Cabin pressure controllers control the quantity of air that flows out of the fuselage through two outflow valves. Two safety valves and a negative-pressure relief valve are installed for safety.

Hope this helps.

PLM

Edited because I'm a plank!

'PondLifeMan', In response to 'is this thread a wind up?'I did say- I apologise in advance if this is achingly obvious.

Or is this not the correct forum for non professionals to ask questions?:confused:

I seem to have recently misplaced my A340 maintenance manual, I am terribly sorry .:hmm:

Phew ..... I thought for a moment my post on the Challenger having a 'wee wee', was going to be attacked .... :p

Alex - pondweed probably has problems with his sexlife and feels the need to take it out on people in anonymous forums...... 'twas a great question and one that caught me out as a turboprop F/O once when taxiiing out!!! I asked my skipper what the open hatch was on the 757 up ahead and he didn't know so we called tower and "helpfully advised the crew" who sat there for a few minutes thinking about it and it turned out to be an outflow valve. So there you go - it's even caught out experienced turboprop crews in the past so yes it WAS a good question! ;)

Thanks WC Fowler :ok: , pondlifeman will be pleased to know I found a maintenance manual now, so no more 'simple' questions :8



P.S- any word on what those large cigar shaped objects with wings are, flying through the sky??? :ouch:

No worries alex ;)

Answer to your next question

[here

Never be afraid to ask questions!

I once sat in my nice warm tower after watching an a/c pushback and said

"ABC123 there appears to be a panel open on the rear port side of your a/c, just infront of and below the level of the rear door."

There was much head scratching ensued, the ground crew couldn't find it, the headset man was completely confuddled. Approximately 10 mins passed blocking the taxiway.

In the end, we got an engineer out to the aircraft, who identified the panel as " something to do with the air conditioning system".

At the time I felt silly. However, looking back on it, I am so glad i mentioned it at the time, and, if I was ever unsure again I would always ask.

The last thing I would want is to try and save my own embarrasement at the time incase I was being silly, and when the a/c commited to the air a whacking great panel fell off!

If in doubt ask - ALWAYS.

As has been said many times before on this website, there are no stupid questions, only stupid answers.

I agree with WCF et al,

A few years ago I was wobbling down a taxiway behind a pax jet in my fat, heavy helicopter, waiting for an IFR departure when me and the co noticed an open panel at the back of the jet.

Rapid discussion within the cockpit led to the answer of ' I'm sure it's sommit normal, let's not bother him with it. He'll only laugh at the thrashing bumble bee behind him anyway.'

Upon take off said jet got an inspection panel warning, turned round, landed again and s***wed up our departure slot!

Just goes to show, there are no stupid questions and occasionally it needs a swift one from the side of the field to perk up the old grey matter and brush complacency aside.

Ask away ( can't always guarantee not to give stupid answers tho!)

:p

Chaps,

I do apologise if I upset anyone. Of course, this is the ideal forum for this kind of question. I have no reasonable excuse for my behaviour.

Anyway, I hope the AMM snippet was helpful.

PLM

Good man Pondie..... Well done! :ok:

While we are preparing for a time of 'goodwill to all men' I think it is time to pull the blinds down on this one.

AlexB - please DO continue to ask questions - I am pleased to see you were not intimidated by some responses :ok:

I too, like 'Turn It Off', have asked about what I thought was an open panel on an aircraft - it wasn't - but I'm glad I asked. Since you began this thread I have explored pics of AB a/c (not my type) and can see what you were asking about. It has been added to my cranial database.:D