View Full Version : Leaky Pressure Hull In Flight

14th Jun 2008, 11:05
Last week my parents were returning to the UK on a 73? when upon reaching cruise altitude the flight crew announced that there was a problem with leaking 'seal'. It seems unclear what the specifics were, however, the word 'seal' appears to have been used. The captain announced that they were able to compensate for the pressure loss and would continue to destination since returning would incur at least a 6 hour delay.

As the flight progressed, the cabin announcements could barely be heard, apparently due to the loudness of the additional pressurization airflow and the first officer appeared in the cabin to re-assure the pax that the problem was under control. (He had to progressively move done the cabin to make himself heard).

As a humble flying instructor who has never flown anything other than light twins, I feel unqualified to comment on the seriousness of this type of problem, but it concerns me enough to solicit remarks on PPrune since I fly quite a lot with this airline myself. Intuitively, leaky pressure seals don't seem like something I'd want to be continuing a flight with in a pressurized environment but I'd appreciate any remarks from anyone more qualified.

Many thanks !

Carnage Matey!
14th Jun 2008, 11:27
No drama at all. All aircraft leak. Probably just a noisy door seal.

one post only!
14th Jun 2008, 11:33
As carnage says the aircraft is never fully "plugged" anyway, the outflow valve (does what it says!!) is always open a certain amount. If a door seal leaks the outflow valve will still be open but by a reduced amount therefore controlling the pressurisation. Noisy but safe.

Notso Fantastic
14th Jun 2008, 11:37
Noisy door seal trapped when the door was closed and allowing a leakage. The loud noise is distressing loud, but totally irrelevant as far as safety is concerned. It is just a comfort thing, nothing more. It happens very infrequently. Certainly not worth disrupting a flight for when the cure is simply earplugs and a good book! Unless you are willing to open the door yourself and reseal it maybe?

14th Jun 2008, 11:51
Agreed, but not an insignificant cost when the drag penalty of various pressure outflows around the pressure cabin and the extra bleed load on the engines are considered; the incremental fuel burn is not insignificant.

Notso Fantastic
14th Jun 2008, 11:54
Like I said, just a comfort thing, nothing more! The extra cost of the bleed load and any imagined drag is completely irrelevant. The outflow valve will compensate with reduced release of air. The only implication is noise and comfort, not any safety effect at all. People- don't start making a drama out of nothing! It can be alleviated by putting wet blankets around the leaky area on the door (if you can identify it) in the hope that moisture leaking out will condense and freeze and block the gap. Purely to cut down the noise nuisance. It used to happen regularly on the 747 and was always dealt with that way.

14th Jun 2008, 12:05
Many thanks for the responses. I am at ease :ok:

14th Jun 2008, 12:05
The instant answer is usually to stuff wet paper towels around the area of the leak. This usually stops the leak and the noise. Renew the paper towels as necessary until repair can be effected.

14th Jun 2008, 12:16
The instant answer is usually to stuff wet paper towels around the area of the leak. This usually stops the leak and the noise. Renew the paper towels as necessary until repair can be effected.

I don't worry about paper towels, but using pillows or blankets can be problamatic when they disappear.

14th Jun 2008, 12:55
When I was flying those old leaky 737's I used my mike in interphone mode to find windshield leaks so maintenance could seal them. It was quite annoying on a six or eight leg day. One day the crew flew from Cancun to LAX at 10,000 feet unpressurised because of a broken door seal with a full airplane with at least one fuel stop. Just the noise from the high IAS must have been awful.

14th Jun 2008, 13:01
An old MX trick to find a leak during a ground pressure run was to have somebody smoke a cigarette inside the cabin around the suspected area. The smoke would then be drawn to the leak and thus identify it.

Notso Fantastic
14th Jun 2008, 13:09
Smoking? Aeroplanes? Heart palpitations! Hidden away in your hangars only please!
But I can see it would work....and let the smokers get 'relief on the job'.

dont overfil
14th Jun 2008, 13:30
Flew as pax few years ago in a Northwest Airbus 320 DTW MCO next to a loudly whistling rear toilet. Door secured with duct tape. No explanation given.

Notso Fantastic
14th Jun 2008, 13:48
Was it whistling a nice tune?

El Grifo
14th Jun 2008, 14:04
An obscure mental leap (or stumble) to "Whistling Rufus" has just taken place.

but that was a long, long time ago on a very different planet. :confused:

14th Jun 2008, 22:21
Whistlin' Rufus???

I seem to recall having that on a 78RPM disc in a recording by Chris Barber's Jazz Band??? "Flashes from the Archives of Oblivion" Yes!!! that it certainly was. Phew, I'd better go and have a lie down after that memory blast. Or, perhaps I'll see if I can find the 78s ... :p

El Grifo
14th Jun 2008, 23:57
The very fellow indeed !!!

Have a little lie down and a stiff single malt, after which, you will be as right as rain :ok:

Happy Daze

El G.

15th Jun 2008, 07:34
Confession time...

Decades ago, in a galaxy far, far away... 737-200 with a faulty door seal at rear left: Howled like a banshee during climb, then settled to a shriek during cruise on our first, outbound sector. Unsurprisingly, customers at rear went nuts - who wouldn't? Tricky sector for us FA's.

The prospect of the return, inbound sector filled us all with some dread - and then a party of 30 deaf customers checked-in and were promptly allocated the back rows. The inbound sector passed without significant comment, apart from the toilet queue.

It was a practical solution to a problem: It worked and nobody got hurt - and to this day I feel uncomfortable about it.


Flight Detent
15th Jun 2008, 08:48
In a general sense only, in line with what "NotsoFantastic" mentioned, the outflow valve(s) will be noticed to be a higher percentage closed in cruise flight with a higher percentage of pressure hull leakage.
And therefore the airplanes capability to maintain differential with only one pack operating, or conversly, with no packs, the time the cabin will take to reach 10,000 feet, from the approximately 8,200 feet at cruise.


keel beam
15th Jun 2008, 18:11
I say BRING BACK SMOKING ON AIRCRAFT. It is easy to see leaks with the nicotine trail.

17th Jun 2008, 09:45
The instant answer is usually to stuff wet paper towels around the area of the leak. This usually stops the leak and the noise. Renew the paper towels as necessary until repair can be effected.

I wonder how much blue-roll the RAF VC10 fleet get through?

18th Jun 2008, 22:22
Came back from Vienna today on a 737-700. Sat next to window at exit row and noticed that window was wet on the inside. When aircraft started to move I got covered in drips from the overhead panel. Anyway take off fine, as we climbed the window started to hiss, the lady behind me got very worried and called one of the crew, i think her words wore something like, don't worry it's just a dodgy seal. There was clearly a leak of some kind, i'm no expert but it seems there are 3 layers? What interested me was that as we got higher the hiss stopped, but the window was froxen solid, could see nothing. As we started to decend, ice melted and the hiss came back.

Why would the hiss stop as we got higher?

18th Jun 2008, 23:54
MarcJF, the leak was likely plugged by the frozen water you speak of.