Amateur-built T 18 N1488 accident near Independence, Oregon

Probable cause

A separation of the canopy mechanism during flight, which resulted in the pilot’s precautionary landing and the airplane’s subsequent collision with a fence post.

NTSB analysis

The pilot departed on a local flight; during initial climb, the canopy partially disconnected from the airplane and the airplane vibrated violently. The pilot made a precautionary landing in a field, and the right wing impacted a fence post. Postaccident examination revealed that the mechanism that allowed the canopy to move fore and aft and retained the aft portion of the canopy during flight separated at a weld, which resulted in airflow into the cockpit. The components were not made available for metallurgical examination and the failure mode could not be determined; however, it is possible that the separation was due to repeated loading on the canopy over time. According to the pilot and a representative of the airplane type club, the canopy design was unique to the accident airplane, and was likely the only one of its kind.

Text from the NTSB. Open the NTSB docket for WPR16LA023 for the full record.