Liberty Aerospace Incorporated LIBERTY XL-2 N519XL incident near Camarillo, California

Probable cause

The cruise flight separation of the canopy door. Contributing to the incident was the pilot's failure to ensure that the left side door was securely closed prior to takeoff.

NTSB analysis

Prior to takeoff, the pilot, who was receiving instrument flight instruction, closed the left side canopy door. The door is composed of a composite material that can be torsionally deformed during the closing and locking process if both the forward and rear door pins are not fully engaged in their respective fuselage frame receptacles. During the door closing operation, the door's aft locking pin was not completely engaged into its receptacle in the door frame. The airplane's flight manual's "Before Takeoff" checklist contains the line item that the doors are to be "CLOSED AND SECURE." The pilot and flight instructor departed for the flight and initially the left side door remained closed; however, the door popped open when the airplane entered an area of moderate turbulence. Thereafter, the left side door's structure ripped apart with the majority of the door separating from the airplane. A portion of the door impacted and dented the left stabilator, and a portion of the door became lodged in the airplane's empennage. The flight instructor took control of the airplane and, unable to maintain altitude, descended and landed at a nearby airport without further incident. After this event, the airplane's manufacturer enhanced the checklist to include the following statement: "Canopy Doors (Both FWD pins and both AFT pins) ENGAGED AND SECURE. [[NOTE]] Verify doors are closed by pushing on aft section of both doors." Also, the manufacturer issued Service Document number SB-09-003, indicating the availability of a tapered aft actuator door pin that, when installed, will facilitate the door's locking pins' engagement into the door frame receptacle.

Text from the NTSB. Open the NTSB docket for WPR09IA187 for the full record.