Incident Overview
Following maintenance on the right engine manifold pressure differential controller, a test flight was performed. During climbout, the right engine upper cowling detached and became wrapped around the right horizontal stabilizer. The pilot reported difficulty controlling the aircraft until airspeed was reduced, after which he returned to the airport and landed safely.
Maintenance Actions
The aircraft had been in maintenance for an adjustment to the right engine manifold pressure differential controller. The procedure required uncowling the engine. A certificated airframe and powerplant mechanic removed the cowling and made the required adjustments, then left for the day. Subsequently, a noncertificated mechanic replaced the cowling before the pilot conducted the post-maintenance test flight.
Cowling Separation Details
Inspection of the cowling after the event revealed that the inboard latches on the upper cowling were not damaged. The cowling separated during climbout and became entangled with the right horizontal stabilizer, leading to handling difficulties. The pilot was able to regain control by reducing airspeed and subsequently landed without further incident.
Pilot's Statement
In a written statement, the pilot noted that his failure to detect the unlatched inboard cowling fasteners resulted from poor preflight inspection habits and a failure to follow the checklist. No further analysis or causal links were provided in the source material.