Window heat

Regarding a picture, I have just sent an email enclosed with, I believe it is a heating film arcing which initiates from laminated bus bar, would you concur with that?

 

Would you concur with the conclusion that the heating film arcing boils down to either faulty window heat control unit or relevant faulty wiring?

Three things normally end a window's life. Both temperature sensors go open, the heater element goes open, or the window cracks.

None of these are uncommon.

It looks like yours cracked. I wouldn't blame the controller as I have never seen one to apply voltage beyond what is required to keep the window warm.

On a side note: Why are window's heated? Beyond the obvious of keeping visibility clear...... window heat keeps it pliable. When a bird hits it, the window will flex and hopefully let the bird bounce off. If the window was cold or frozen, the window will shatter and possibly have the bird come through.

Regarding pages of task card I have just emailed, the observed damage is not similar to typical pattern of cracked outer pan, inner pan and vinyl interlayer

Does it really matter where it cracked? We don't examine or are we concerned about what layer let go. We just change it.

The repair facility might look it over and determine if engineering changes are required, but these types of windows have been used 30+ years now.

They have a pretty good track record.

Well it does matter when an air carrier needs to tackle root cause of unreliability of cabin window anti icing, CWAI,(I.e. whether it boils down to faulty wiring/controller or to the structural integrity issues), Given that PPG has modified the sliding window to address the safety concern that FAA sets out in AD2008-09-15.

Way above my pay grade.