Narrative:

While en route to ZZZ from ZZZ1 at cruise altitude FL360; the pilot monitoring heard an abnormal cracking sound in the cockpit. After investigating; the pilot monitoring (first officer) noticed that the #4 first officer eyebrow window appeared to be cracked. After careful removal of the sunshield; it was confirmed. The QRH was referenced and the affected cracked window checklist was completed. The flight crew relayed the event to company via comrdo. The flight continued to ZZZ1 with a higher cabin altitude selected as per the QRH. Flight landed without incident and no further damage was discovered. After landing and discussing the event with maintenance and other flight crews; it was learned that aircraft had a logged bird strike earlier near the area in question. No damage from that strike could be found; confirmed; or logged. I suspect that the window was weakened by the strike and eventually failed. That is my assumption. Callback conversation with reporter revealed the following information: reporter stated the sound was very different from normal cockpit noise; almost similar to crunching up a sheet of dry newspaper. The abnormal sound lasted only a couple of seconds and was gone. He has not heard from maintenance; which side of the window actually cracked -- the inner or outer pane.

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Original NASA ASRS Text

Title: A B737-700 PILOT REPORTS OF HEARING AN ABNORMAL CRACKING SOUND IN THE COCKPIT. THE #4 EYEBROW WINDOW WAS FOUND CRACKED.

Narrative: WHILE ENRTE TO ZZZ FROM ZZZ1 AT CRUISE ALT FL360; THE PLT MONITORING HEARD AN ABNORMAL CRACKING SOUND IN THE COCKPIT. AFTER INVESTIGATING; THE PLT MONITORING (FO) NOTICED THAT THE #4 FO EYEBROW WINDOW APPEARED TO BE CRACKED. AFTER CAREFUL REMOVAL OF THE SUNSHIELD; IT WAS CONFIRMED. THE QRH WAS REFERENCED AND THE AFFECTED CRACKED WINDOW CHKLIST WAS COMPLETED. THE FLT CREW RELAYED THE EVENT TO COMPANY VIA COMRDO. THE FLT CONTINUED TO ZZZ1 WITH A HIGHER CABIN ALT SELECTED AS PER THE QRH. FLT LANDED WITHOUT INCIDENT AND NO FURTHER DAMAGE WAS DISCOVERED. AFTER LNDG AND DISCUSSING THE EVENT WITH MAINT AND OTHER FLT CREWS; IT WAS LEARNED THAT ACFT HAD A LOGGED BIRD STRIKE EARLIER NEAR THE AREA IN QUESTION. NO DAMAGE FROM THAT STRIKE COULD BE FOUND; CONFIRMED; OR LOGGED. I SUSPECT THAT THE WINDOW WAS WEAKENED BY THE STRIKE AND EVENTUALLY FAILED. THAT IS MY ASSUMPTION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE SOUND WAS VERY DIFFERENT FROM NORMAL COCKPIT NOISE; ALMOST SIMILAR TO CRUNCHING UP A SHEET OF DRY NEWSPAPER. THE ABNORMAL SOUND LASTED ONLY A COUPLE OF SECONDS AND WAS GONE. HE HAS NOT HEARD FROM MAINT; WHICH SIDE OF THE WINDOW ACTUALLY CRACKED -- THE INNER OR OUTER PANE.

Data retrieved from NASA's ASRS site as of January 2009 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.