Czech Aircraft Works Sportcruiser N334BB accident near San Diego, California

Probable cause

The inadvertent opening of the aircraft canopy during the takeoff climb, which distracted the pilot and resulted in his failure to maintain aircraft control. Contributing to the accident was a lack of guidance in the manufacturer's pilot operating handbook addressing an open canopy during flight.

NTSB analysis

The pilot reported that the airplane was about 50 feet above ground level during the takeoff climb when the right side of the canopy opened about 4 to 6 inches. As he reached to lower it, the left side of the canopy opened. The canopy was moving up and down erratically as the pilot attempted to stabilize it, and the airplane began pitch oscillations. The pilot notified the air traffic control tower controller that the canopy was open and that he needed to return for landing immediately. As the pilot turned onto the downwind leg of the traffic pattern, the pitch oscillations became increasingly erratic. The airplane lost altitude and subsequently collided with power lines, which pitched the airplane upside down into the street below.

Postaccident examination of the canopy noted that it was hinged in front of the cockpit and rotated forward when open. Examination of the latch mechanism revealed no mechanical anomalies.

The pilot reported that he followed the takeoff checklist and ensured that the canopy was closed and locked by pushing up on it, although this instruction was not in the pilot operating handbook (POH). Further examination of the POH noted a lack of guidance for verifying that the canopy was locked or for operating the airplane when the canopy inadvertently opened. It is likely that during the preflight, the canopy latches could have been partially engaged such that the pilot felt enough resistance to believe that the canopy was locked. The vibration encountered during the takeoff roll and the aerodynamic flow over the canopy at liftoff may have caused the canopy to become loose and open. After the accident, the manufacturer issued guidance indicating that if the canopy opened in flight, it would raise about 2 to 3.2 inches, but the airplane should remain fully controllable.

Text from the NTSB. Open the NTSB docket for WPR10LA276 for the full record.