Airborne planes' windshields crack in cold in Denver


#1

cnn.com/2007/WEATHER/02/17/w … index.html

Story about an ‘epidemic’ of cracked windshields at Denver in the cold this last storm. This link talks about airborne airplanes, but other stories were saying some were on the ground. Sounds like it was just so fast moving that windsheilds were just brittle. This link also talks about a Council Bluffs Iowa Cessna 340 that went down. I can believe it–the cold and winds were pretty nasty these last few days. Just found it interesting.


#2

This one talks about some of the ones on the ground that cracked. Very strange.


#3

Tried the link but it says the page can not be found.


#4

He added “” as part of the link. Take that away, and it should work.


#5

Fixed it now. Thanks. Not enough coffee yet.


#6

As usual, I have a theory based on nothing solid but a not-so-scientific wild guess.

The sun has been shining and heating up Denver pretty seriously during the day. I suspect the lapse rate is pretty serious. Is it possible that the extreme change in temp from flight to ground and back is the culprit?

How fast and big of a swing in temp would it take to crack one of those windows?


#7

The temperature change from altitude to landing is pretty gradual. More than likely the windscreen problems come from pilots turning on the anti ice. Most systems have a low setting to slowly warm the window before you take it to high and blast it with heat, with either bleed air or a heating element. If you go straight to high then you are more likely to break the windscreen. Typical pilot error is my guess.


#8

So much for global warming!


#9

Consider yourself globally warned.


#10

Okay, heard two new(?) theories.

One is windscreen heater malfunction, but the odds of such a huge cluster suddenly appearing on different planes in different fleets seems to cancel this one out to me.

The other is that the power supplied by the airport to the planes is somehow causing the problem due surges or something.

There was an aborted take off today. Has anyone seen data on whether all these planes are leaving the airport or not. I have not heard of any of these being on arrival, they seem to be on ground, or on departure.

My initial theory seems to be lame to me now, but I got nothin better than the dirty power idea. I don’t have the knowledge if these systems to understand how bad power could cause this.


#11

If the ground power isn’t putting out just the right juice the airplane won’t accept it. At least that’s how it worked on the 737’s and 319/320’s I used to work with. It will just click off.
It is lame, mooney.
…though I have no better answer.


#12

Heres a nice picture.

CRACK


#13

This was only a mystery because they claimed it wasn’t FOD.

Well, it was FOD. They found sand in the cracks from the deicing of he runways and taxiways.

Man, that takes all the fun out of it, don’t it?


#14

So they’re saying sand broke the windshields? :question:


#15

They said they found sand in the cracks, and are blaming FOD from the sanding for ice.

I suppose the cracks were caused by larger bits of sand that rebounded after impact, leaving little bits behind. Some of the breaks were probably post impact due to other stresses acting on the impacted area, like change in temp?