What happened
On May 22, 2016, a SAAB-340A operated by SprintAir SA was performing a scheduled flight from Warsaw Chopin Airport (EPWA) to Gdansk (EPGD). At approximately 20:05 UTC, while cruising at flight level 200, the outer heating layer of the left cockpit window cracked. The incident did not result in a loss of cabin pressure.
Upon discovering the crack, the flight crew decided to terminate the flight and return to the departure airport. The return flight and subsequent landing at Warsaw were completed without further complications.
The investigation
The investigation, conducted by the operator, examined the circumstances surrounding the window failure and reviewed the maintenance history of the aircraft type. During the review of the 12 months preceding the incident, it was established that three other instances of cockpit window failures had occurred on this aircraft type, all of which required window replacements. These previous incidents included one case of delamination, one crack, and one instance of heating system malfunction.
Findings
- The crack was limited to the external heating layer of the window.
- No decompression occurred during the flight.
- The most probable cause of the incident was operational wear of the window heating system.