Narrative:

Due to a thunderstorm approaching bwi; told we could not hold at the gate. We taxied to deicing pad to wait while the field was closed. Captain asked me to send dispatch a message informing them of this. Expected delay was to be around 40 mins. While I was typing the dispatch message; the captain shut down both engines without calling for the shutdown checklist. Upon noticing the engines shutting down; I did my after lng and shutdown flow; turning off the window heat during this process. When we started up and departed; we used the appropriate checklist but never turned the window heat back on. During departure; we went through light; maybe occasional moderate rain; but got speed below 250 KTS below 10000 ft. We climbed to FL410. During cruise; we heard 3 loud bangs/pops that sounded like something heavy dropped in the cockpit or maybe a flight attendant slamming their bins. The captain said it was probably aircraft popping(?) upon descent into los angeles; the windows started to freeze up and the captain noticed the window heat was off; so he turned it on and we opened up our window vents while increasing the cockpit air temperature. During descent we went through 1 cloud with light turbulence but no rain. We landed uneventfully. Upon leaving the aircraft; I noticed that both windows over each pilot's head were shattered. We feel that the popping noise during cruise was when the windows broke but can't be sure. In fact; we can't say for sure that the windows were not broken when we got the aircraft. We flew 2 legs prior to this but these windows are covered by green sun filters and I think the only reason I noticed the windows in los angeles was that the overhead gate lights were shining through these and I had recently flown another aircraft with these windows broken on MEL. Maintenance thinks they broke when we turned the heat on and suggested that if a similar situation arises; don't turn heat on with an already cold window. The MEL for inoperative window heat says only to keep speed below 10000 ft; which we did. The windows should not have broken by the way we flew the plane and we are wondering if we should have turned the heat on or not once airborne for a long time. Also; our procedures for shutting down an engine say not to move any switches except those called by the shutdown checklist. Does this mean that we keep the start switches in left continuous for the entire time we are shut down; or is an after shutdown flow expected?

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Original NASA ASRS Text

Title: B737-700 FLT CREW NEGLECTS TO TURN THE WINDOW HEAT ON. THE ACFT BECOMES COLD SOAKED AT FL410. FLT CREW TURNS ON WINDOW HEAT UPON ENTERING ICING DURING DSCNT. UPON ARR IT IS NOTICED THAT THE EYEBALL WINDOWS HAD SHATTERED.

Narrative: DUE TO A TSTM APCHING BWI; TOLD WE COULD NOT HOLD AT THE GATE. WE TAXIED TO DEICING PAD TO WAIT WHILE THE FIELD WAS CLOSED. CAPT ASKED ME TO SEND DISPATCH A MESSAGE INFORMING THEM OF THIS. EXPECTED DELAY WAS TO BE AROUND 40 MINS. WHILE I WAS TYPING THE DISPATCH MESSAGE; THE CAPT SHUT DOWN BOTH ENGS WITHOUT CALLING FOR THE SHUTDOWN CHKLIST. UPON NOTICING THE ENGS SHUTTING DOWN; I DID MY AFTER LNG AND SHUTDOWN FLOW; TURNING OFF THE WINDOW HEAT DURING THIS PROCESS. WHEN WE STARTED UP AND DEPARTED; WE USED THE APPROPRIATE CHKLIST BUT NEVER TURNED THE WINDOW HEAT BACK ON. DURING DEP; WE WENT THROUGH LIGHT; MAYBE OCCASIONAL MODERATE RAIN; BUT GOT SPD BELOW 250 KTS BELOW 10000 FT. WE CLBED TO FL410. DURING CRUISE; WE HEARD 3 LOUD BANGS/POPS THAT SOUNDED LIKE SOMETHING HVY DROPPED IN THE COCKPIT OR MAYBE A FLT ATTENDANT SLAMMING THEIR BINS. THE CAPT SAID IT WAS PROBABLY ACFT POPPING(?) UPON DSCNT INTO LOS ANGELES; THE WINDOWS STARTED TO FREEZE UP AND THE CAPT NOTICED THE WINDOW HEAT WAS OFF; SO HE TURNED IT ON AND WE OPENED UP OUR WINDOW VENTS WHILE INCREASING THE COCKPIT AIR TEMP. DURING DSCNT WE WENT THROUGH 1 CLOUD WITH LIGHT TURB BUT NO RAIN. WE LANDED UNEVENTFULLY. UPON LEAVING THE ACFT; I NOTICED THAT BOTH WINDOWS OVER EACH PLT'S HEAD WERE SHATTERED. WE FEEL THAT THE POPPING NOISE DURING CRUISE WAS WHEN THE WINDOWS BROKE BUT CAN'T BE SURE. IN FACT; WE CAN'T SAY FOR SURE THAT THE WINDOWS WERE NOT BROKEN WHEN WE GOT THE ACFT. WE FLEW 2 LEGS PRIOR TO THIS BUT THESE WINDOWS ARE COVERED BY GREEN SUN FILTERS AND I THINK THE ONLY REASON I NOTICED THE WINDOWS IN LOS ANGELES WAS THAT THE OVERHEAD GATE LIGHTS WERE SHINING THROUGH THESE AND I HAD RECENTLY FLOWN ANOTHER ACFT WITH THESE WINDOWS BROKEN ON MEL. MAINT THINKS THEY BROKE WHEN WE TURNED THE HEAT ON AND SUGGESTED THAT IF A SIMILAR SITUATION ARISES; DON'T TURN HEAT ON WITH AN ALREADY COLD WINDOW. THE MEL FOR INOP WINDOW HEAT SAYS ONLY TO KEEP SPD BELOW 10000 FT; WHICH WE DID. THE WINDOWS SHOULD NOT HAVE BROKEN BY THE WAY WE FLEW THE PLANE AND WE ARE WONDERING IF WE SHOULD HAVE TURNED THE HEAT ON OR NOT ONCE AIRBORNE FOR A LONG TIME. ALSO; OUR PROCS FOR SHUTTING DOWN AN ENG SAY NOT TO MOVE ANY SWITCHES EXCEPT THOSE CALLED BY THE SHUTDOWN CHKLIST. DOES THIS MEAN THAT WE KEEP THE START SWITCHES IN L CONTINUOUS FOR THE ENTIRE TIME WE ARE SHUT DOWN; OR IS AN AFTER SHUTDOWN FLOW EXPECTED?

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.