Aero Vodochody L-39 N39WT accident near Boulder City, Nevada

Probable cause

An in-flight emergency followed by a collision with terrain for reasons that could not be determined because postaccident examination of the airframe, engine, and forward and aft canopies revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

NTSB analysis

Upon arrival at the airport, the pilots of the accident airplane and of another airplane flying at the same time briefed the passengers on what to expect during their adventure flight, and they subsequently began the first of four planned flights. The first two flights were uneventful. The accident occurred during the third flight of the day.

A review of the UNICOM radio communications revealed that, shortly after the airplanes took off, the accident pilot announced, "canopy, canopy." The lead airplane pilot asked the accident pilot if he was heading back; the accident pilot's response could not be understood. The accident airplane subsequently made a right descending turn and impacted a berm in desert terrain at a high descent rate and then bounced about 200 feet before coming to rest about a 1/2 mile from the airport. The airplane came to rest between two sets of power lines next to an access road. First responders to the accident site reported that both of the airplane's canopies were closed and that the engine remained running for about 20 minutes before it shut down on its own.

A postaccident examination of the airplane, engine, and forward and aft canopies revealed no mechanical malfunctions or failures that would have precluded normal operation. If one of the canopies had somehow become displaced, the canopy illumination warning light would have activated, and the pilot should have followed the emergency procedures, which state, in part, to land as soon as practical, and likely would have been able to control the airplane and land. The reason for the pilot's radio transmission about the canopy and his initiation of a right descending turn could be determined.

Text from the NTSB. Open the NTSB docket for WPR12FA216 for the full record.