bongo
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Window Cracked In Flight, Procedure? (pic)

Sat Jun 16, 2007 11:13 pm

What is the procedure in this case?
Three hours before landing, over the atlantic, must be scary!


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xjramper
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RE: Window Cracked In Flight, Procedure? (pic)

Sat Jun 16, 2007 11:22 pm

This thread needs to be moved over to tech ops.

But my recollection says that its actually a two pained glass. This has been discussed before. But lets atleast get this to the correct forum.

XJR
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aileron11
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RE: Window Cracked In Flight, Procedure? (pic)

Sun Jun 17, 2007 12:32 am

From looking at the picture, I say the visabality is bad, but if he can use the wipers the visabality will improve. Most of the blurr is from the rain not the cracks.
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OPNLguy
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RE: Window Cracked In Flight, Procedure? (pic)

Sun Jun 17, 2007 12:48 am

Unlike what the movies show ("Cliffhanger" and "Eraser" come to mind), aircraft windshields are not single pane glass and do not shatter, per se. They are made from multiple layers with heating elements in between, and the inner and outer panes are glass.

IIRC from a previous thread, the picture in question shows that the outer pane has cracked, and the rest of the window is fine. If an inner pane cracks, one usually has to lower the cabin pressure differential and one decends to a lower altitude. I say "usually" because I'm not familar with every QRH for every different aircraft out there.
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MD11Engineer
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RE: Window Cracked In Flight, Procedure? (pic)

Sun Jun 17, 2007 7:19 am

Aircraft windshields resemble bullet proof glass. They usually consist of 3-5 layers of mineral glass alternating with acrylic (total thickness about 1-2 inches and very heavy).
Between the outer (mineral glass) and the next layer there is a conductive layer, through which electric current is routed for windscreen heating. The temperature is being regulated by a window heat controller unit (WHCU) using a small temperature sensor laminated into the window. In this case I think that the WHCU or the sensor were defective, causing the outer layer of window to overheat and crack. Obviously the window will have to be changed on ground.

Jan
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mohunk
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RE: Window Cracked In Flight, Procedure? (pic)

Sun Jun 17, 2007 11:17 am

Try:

www.acaptainslog.blogspot.com/2007_04_01_archive.html

for more on shattered windshields.
 
A320ajm
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RE: Window Cracked In Flight, Procedure? (pic)

Mon Jun 18, 2007 5:46 pm

Quoting Bongo (Thread starter):
What is the procedure in this case?

I think for the procedures you descend to a lower altitude to relieve the pressure of the screen. You are supposed to turn the heating off the windscreen because this can cause the crack to get worse. Finally, i would suspect that the crew, both cabin and flight, would be prepared for an emergency descent and procedures in case the screen broke, such as what happened on BA flight 5390. This would then be classed as a rapid decompression and the procedures would be taken from there.
Thanks
A320ajm
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greasespot
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RE: Window Cracked In Flight, Procedure? (pic)

Mon Jun 18, 2007 6:01 pm

Quoting A320ajm (Reply 7):
think for the procedures you descend to a lower altitude to relieve the pressure of the screen

 no  On the B727 and B737 You just fly normally. The MEL even lets the airplane be dispatched on the capt's discretion if there is no maintence avaliable at the base. It says something about as long as the pilot vies is not distorted...

GS
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jamesbuk
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RE: Window Cracked In Flight, Procedure? (pic)

Mon Jun 18, 2007 8:55 pm

Quoting A320ajm (Reply 7):
lower altitude to relieve the pressure of the screen

Just out of interest, isnt that a bit of "6 and 2, 3's" ? If your higher up you have a bigger pressure diferential but if you descend you have denser air hitting the screen maybe forcing a crack further. Thoughts?

Rgds --James--
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flymatt2bermud
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RE: Window Cracked In Flight, Procedure? (pic)

Tue Jun 19, 2007 1:03 am

Our SOP in the event of a cracked windshield is pretty straight forward.....1) JUMP.

Sorry, I couldn't help myself. All aircraft windshields by certification must be able to withstand cracking beyond typical exposure. I flew the Challenger 601 and 604. They had acrylic windshields which have a history of failure. Most incidents of 601 or 604 cracked windshields are within tolerance for dispatch or continued trips with an hourly and/or short calendar limitation. We found the best way to prevent cracking was to wax the windshields once a month. This would prevent moisture from getting between the windshield layers and we never had a problem with our aircraft. The waxing of windshields was also bery beneficial as the Challenger 600 models do not have wipers.
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A320ajm
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RE: Window Cracked In Flight, Procedure? (pic)

Tue Jun 19, 2007 1:38 am

Quoting Jamesbuk (Reply 8):
Just out of interest, isnt that a bit of "6 and 2, 3's" ? If your higher up you have a bigger pressure differential but if you descend you have denser air hitting the screen maybe forcing a crack further. Thoughts?

Rgds --James--

But there is less of a differential from the outside to the inside, as the pressure in the cabin is similar to that of a low altitude.
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A320ajm
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HAWK21M
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RE: Window Cracked In Flight, Procedure? (pic)

Wed Jun 20, 2007 8:24 pm

Quoting Greasespot (Reply 7):
On the B727 and B737 You just fly normally. The MEL even lets the airplane be dispatched on the capt's discretion if there is no maintence avaliable at the base. It says something about as long as the pilot vies is not distorted...

Any MEL reference.
regds
MEL
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