Gulfstream American Corp. G-1159A N155MM incident near Farmingdale, New York

Probable cause

Progressive cracking from an undetermined initiation source, which resulted in the failure of the No. 4 cabin window outer pane, and the subsequent foreign object ingestion to the right engine.

NTSB analysis

The pilot-in-command stated that while passing through 35,000 feet mean sea level, the flightcrew heard a sound similar to a compressor stall, followed by a loss of power to the right engine. He immediately declared an emergency with air traffic control and initiated the checklist items for engine shutdown in-flight. Shortly thereafter, the cabin service representative informed him that the No. 4 outer window pane on the right side of the airplane had separated. The flightcrew made a visual approach back to the departure airport and landed without further incident.

A bore scope examination of the engine revealed that it had experienced a compressor stall and flamed out as a result of debris from the No. 4 outer window pane being ingested into the engine. Review of the airplane logbooks revealed that all required inspections had been conducted on the window and no anomalies were noted. Further examination of the window revealed fractures in the outer pane, which originated from an area of preexisting progressive cracking, emanating from the exterior surface of the window. The initial cause of the cracking could not be determined.

Text from the NTSB. Open the NTSB docket for ERA10IA170 for the full record.