Md Helicopter 369E N155NR accident near Brainerd, Minnesota

Probable cause

The failure of the helicopter’s windscreen for reasons that could not be determined based on the available information, which resulted in substantial damage to the main rotor blades and horizontal stabilizer.

NTSB analysis

The commercial pilot reported that, during an aerial observation flight near known thunderstorms, the right center windscreen shattered. The pilot sustained multiple facial lacerations, but he was able to land the helicopter near a highway without further incident. The pilot reported that he did not see anything strike the windscreen and found no evidence of a bird strike.

Examination of the helicopter revealed that debris from the windscreen substantially damaged two of the main rotor blades and the leading edge of the horizontal stabilizer. Examination of the windscreen and its frame revealed evidence of cracking that originated in the center of the windscreen and propagated outward, consistent with impact forces from outside the helicopter.

DNA from samples taken from portions of the windscreen matched DNA from a Western Kingbird; however, given the extent of the damage to the windscreen, the small size of the Western Kingbird, and the pilot's statement, it is likely that this DNA was due to a previous bird strike and did not result in the failure of the windscreen. Therefore, the reason for the windscreen failure could not be determined.

Text from the NTSB. Open the NTSB docket for GAA16LA325 for the full record.