Narrative:

Earlier in flight a high pitched squeal started and first officer noticed what appeared to be a 1 inch crack at the lower corner of the window. As a precaution we descended to FL210. FL230 was recommended by maintenance and dispatch which had us landing ZZZ with less than far 45 mins. We notified ATC of minimum fuel and were cleared direct ZZZ. Shortly after checking in with ZZZ center they advised us that we would have to declare an emergency or return to our original route. We opted to declare the emergency at that time rather than fly the route anticipating that we would have less than 30 mins when landing in ZZZ if we did so.

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Original NASA ASRS Text

Title: AFTER AN A319 WINDOW CRACKED; THE CREW DESCENDED; DECLARED AN EMER TO GET ROUTING DIRECT TO THEIR DEST BECAUSE OF FUEL CONSIDERATIONS AT THE LOWER ALT.

Narrative: EARLIER IN FLT A HIGH PITCHED SQUEAL STARTED AND FO NOTICED WHAT APPEARED TO BE A 1 INCH CRACK AT THE LOWER CORNER OF THE WINDOW. AS A PRECAUTION WE DSNDED TO FL210. FL230 WAS RECOMMENDED BY MAINT AND DISPATCH WHICH HAD US LNDG ZZZ WITH LESS THAN FAR 45 MINS. WE NOTIFIED ATC OF MINIMUM FUEL AND WERE CLRED DIRECT ZZZ. SHORTLY AFTER CHKING IN WITH ZZZ CTR THEY ADVISED US THAT WE WOULD HAVE TO DECLARE AN EMER OR RETURN TO OUR ORIGINAL RTE. WE OPTED TO DECLARE THE EMER AT THAT TIME RATHER THAN FLY THE RTE ANTICIPATING THAT WE WOULD HAVE LESS THAN 30 MINS WHEN LNDG IN ZZZ IF WE DID SO.

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.