Narrative:

I was in the right seat performing the duties of flying pilot. We first noticed a brownish streak rapidly develop along the lower edge of the 1L window with some arcing in it. A small bubble was developing on the left end of the brownish stripe. The bubble on the left end expanded rapidly and before we could turn off the power to the 1L window heat; with a loud pop the window cracked and the power failed. We ran the window damage QRH and reviewed; but did not accomplish; window heat QRH. After conferring with dispatch; we determined that the cracking was on the outside pane; that there was no evidence of deformation or air leak; it was not structural and it was; therefore; safe to continue. We did raise the cabin altitude manually to approximately 8;700 feet; in order to reduce the differential pressure and requested expedited service from ATC in order to shorten the flight in our degraded condition. We also operated at reduced speed after mach/airspeed crossover. After an uneventful landing; we taxied to the gate and; after shutdown; I entered the window failure in the aml. I believe the cause of the event was the shorting of the 1L heating elements; causing excessive heating and subsequent failure of the outer window pane. I would like to see some guidance in the QRH for additional things to consider if a descent/diversion is not required or performed such as manually reducing the cabin differential pressure by raising the cabin altitude.

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Original NASA ASRS Text

Title: A B757-200 Flight Crew encountered a cracked and delaminated outer pane of the Captain's windshield on an ETOPS flight. Due to the long range nature of the flight they took non QRH directed precautions by reducing cabin pressure differential; reducing airspeed and requesting/receiving expedited handling from ATC.

Narrative: I was in the right seat performing the duties of flying pilot. We first noticed a brownish streak rapidly develop along the lower edge of the 1L window with some arcing in it. A small bubble was developing on the left end of the brownish stripe. The bubble on the left end expanded rapidly and before we could turn off the power to the 1L window heat; with a loud POP the window cracked and the power failed. We ran the Window Damage QRH and reviewed; but did not accomplish; Window Heat QRH. After conferring with dispatch; we determined that the cracking was on the outside pane; that there was no evidence of deformation or air leak; it was not structural and it was; therefore; safe to continue. We did raise the cabin altitude manually to approximately 8;700 feet; in order to reduce the differential pressure and requested expedited service from ATC in order to shorten the flight in our degraded condition. We also operated at reduced speed after Mach/Airspeed crossover. After an uneventful landing; we taxied to the gate and; after shutdown; I entered the window failure in the AML. I believe the cause of the event was the shorting of the 1L heating elements; causing excessive heating and subsequent failure of the outer window pane. I would like to see some guidance in the QRH for additional things to consider if a descent/diversion is not required or performed such as manually reducing the cabin differential pressure by raising the cabin altitude.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.