Narrative:

Emergency window separated from aircraft during straight and level cruise. 1972 piper aztec. Note: aircraft annual completed approximately 40 mins prior to event. Did mechanic fail to latch window? If so, I failed to notice during preflight.

Google
 

Original NASA ASRS Text

Title: PLT FLYING AN AZTEC HAS 'EMER WINDOW' SEPARATE FROM ACFT INFLT. ACFT ANNUAL JUST COMPLETED PRIOR TO FLT.

Narrative: EMER WINDOW SEPARATED FROM ACFT DURING STRAIGHT AND LEVEL CRUISE. 1972 PIPER AZTEC. NOTE: ACFT ANNUAL COMPLETED APPROX 40 MINS PRIOR TO EVENT. DID MECH FAIL TO LATCH WINDOW? IF SO, I FAILED TO NOTICE DURING PREFLT.

Data retrieved from NASA's ASRS site as of July 2007 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.