Narrative:

While climbing to 7;500 ft MSL at an indicated airspeed of 140 KIAS; a window on the left side of the aircraft that has the ability to be opened on the ground; but was secured and locked closed; suddenly opened and extended the lower portion of the window approximately two inches into the slipstream. The passenger seated next to the window tried to pull the lower portion inboard and re-latch it; but was unable to do so. In a matter of ten seconds; the window dislodged from the brackets holding the upper part of the window to the aircraft and the window flew off the aircraft passing above the left horizontal stabilizer and into the air. I elected to maintain a slow speed of 150 KIAS and descended to 5;500 MSL and continued the flight without further incident. This incident occurred over open farmland in a sparsely populated farming community. I chose not to circle; as I felt I would not be able to determine the location of the window and felt it much more important that I determine the need to return to departure airport or proceed to destination where the aircraft is based in order to affect repairs. The aircraft was stable and completely controllable at all times. In many years of owning this aircraft; I have never had one of the side windows open during flight. In view of the fact that the aircraft can be operated with the rear passenger doors removed; I felt that it was perfectly safe to proceed to my destination for repairs. I did not notify ATC during approach; as I felt I required no special handling in the event of a go-around during my approach. Approach and landing were accomplished without a problem.

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Original NASA ASRS Text

Title: A B58 pilot reported losing a window in flight. He chose to continue to destination where a normal landing was made.

Narrative: While climbing to 7;500 FT MSL at an indicated airspeed of 140 KIAS; a window on the left side of the aircraft that has the ability to be opened on the ground; but was secured and locked closed; suddenly opened and extended the lower portion of the window approximately two inches into the slipstream. The passenger seated next to the window tried to pull the lower portion inboard and re-latch it; but was unable to do so. In a matter of ten seconds; the window dislodged from the brackets holding the upper part of the window to the aircraft and the window flew off the aircraft passing above the left horizontal stabilizer and into the air. I elected to maintain a slow speed of 150 KIAS and descended to 5;500 MSL and continued the flight without further incident. This incident occurred over open farmland in a sparsely populated farming community. I chose not to circle; as I felt I would not be able to determine the location of the window and felt it much more important that I determine the need to return to departure airport or proceed to destination where the aircraft is based in order to affect repairs. The aircraft was stable and completely controllable at all times. In many years of owning this aircraft; I have never had one of the side windows open during flight. In view of the fact that the aircraft can be operated with the rear passenger doors removed; I felt that it was perfectly safe to proceed to my destination for repairs. I did not notify ATC during approach; as I felt I required no special handling in the event of a go-around during my approach. Approach and landing were accomplished without a problem.

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.