AAIB investigation to Piper PA-31, G-UKCS
Uncommanded cabin door opening in flight, near Hull, Yorkshire, 23 July 2021.
Summary:
The aircraft’s lower cabin door came open in flight when a screw forming part of the door’s forward latching mechanism fractured. The aircraft landed safely and the investigation determined that the cabin door’s rear latch was probably not locked when the cabin door was closed, allowing the door to open when the screw fractured. The screw had not been securely fastened and was loose, which contributed to a fatigue failure of the screw. The operator has taken a number of safety actions intended to detect unsafe conditions of the cabin doors on its PA-31 fleet.
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