Frost Forming In The Cabin Of Ryanair Flight

[BMI701EGCC]

Evening everyone,

I want to comment on the experience i had on my flight from BUD to LPL (738 flt no 4233) yesterday evening, We departed approx 20:00h local time. Our flight was delayed about 15 minutes due to two passengers being late, once the straddlers where onboard the crew shut the doors, we then started a much needed deicing procedure.

Anyway, we where about half way through our flight (-40 OAT), when i saw what i thought was a sticker on the panel just under the window line (sat centre of the right wing, behind the exit), i touched it as i was curious to what it was, it was defiantly frost forming. I glanced over to the seat in front to see if it was the same and it was, but much worse. I didn't call the FA as i wasn't sure if they're was something wrong.

As a side note, i want to thank the crew for a great landing, was extremely windy, just about managed to land the plane. great crabbing!

Hopefully someone could shed some light on this.

PS. the frost was about 2 inch by 10 inch on each panel

scott

[tescoapp]

Its proberly the bracket that attaches the panel to the airframe. The metal conducts the heat to the outside and chills the patch down to below freezing.
All the pax sweat and breath condenses and forms the frost.

Up the front on sometypes you have to watch putting your arm/hand anywhere near the window fittings on the unheated ones. You only do it once but it is quite possible to get a cold burn or even stick to DV window rails. And once you go through the freezing level you have cold dripping water down your arm for much of the approach.

[BMI701EGCC]

cheers for the clarification tescoapp, much appriciated!

scott

[rasobey]

Tescoapp - I ALWAYS wondered why, at the end of a FR flight, I was wet. Cheers :)

PS - I'm sure it applies to other operators using the same type :p

[tescoapp]

To be fair its not just a feature of ryans or that aircraft type.

All aircraft will get it forming on the hull where you can't see it. Usually they have valves at the bottom of the hull which open at somepoint after landing which vents the condersate which has melted and run down into the belly.

Which is why you sometimes see patches of water under the aircraft on a dry ramp on stand.

It is quite a common question from new ramp handelers what the patches are.

Usually we wait until they have stuck thier finger in the puddle to see if its oil/fuel before we kid them on its overflow from the toilets before telling them the truth.

[3bars]

Usually they have valves at the bottom of the hull which open at somepoint after landing which vents the condersate which has melted and run down into the belly.



REALLY???? Valves opening????:E Not in any airplane I was an engineer on.

[tescoapp]

Go on then educate me how its done. You get told on your type ratings then you never think about it again.

Current type its a load of flap valves which get pushed shut when the plane pressurises then spring open again when you de-pressurise

[Storminnorm]

It's a common event on freight aircraft, especially carrying fruit and flowers.
Aren't the spaces between the inner scratch panel and the outer pressure
panels supposed to be "filtered" via silica gel or some other form of drying
medium?

[Fargoo]

REALLY???? Valves opening???? Not in any airplane I was an engineer on.

All the boeings i've worked on have them. Small screw in plastic valves that are spring loaded open and shut themselves with cabin pressure.

[IFixPlanes]

... Small screw in plastic valves that are spring loaded open and shut themselves with cabin pressure.
B737:
http://img132.imageshack.us/img132/3244/b737drainagevalvejv8.th.jpg (http://img132.imageshack.us/my.php?image=b737drainagevalvejv8.jpg) http://img129.imageshack.us/img129/5669/b737drainagevalvepositihh3.th.jpg (http://img129.imageshack.us/my.php?image=b737drainagevalvepositihh3.jpg)

[BMI701EGCC]

cheers guys for the replies, great depth.

[ChristiaanJ]

Aren't the spaces between the inner scratch panel and the outer pressure panels supposed to be "filtered" via silica gel or some other form of drying medium?Yes, although they don't necessarily use silica gel!
This discussion is about condensation > frost inside the cabin itself.

[fruitloop]

Thanks IFixPlanes.I'm trying to decide which model 737 you have displayed.First thought was a 100 but didn't think any-one else was as old as me !!! BTW usually closed around 1.5 psid..:D:D

[IFixPlanes]

...I'm trying to decide which model 737 you have displayed. ...It is an overview out of 737CL AMM (51-41-00 Page 2)

...BTW usually closed around 1.5 psid ...
AMM 21-00-05 Page 103 (AIRPLANE/STRUCTURE AIR LEAKAGE)
BTW : it is helpful to read fact before nitpicking ;)