Amateur-built AVIPRO BEARHAWK N652BH accident near Roxbury, Maine

Probable cause

The pilot’s unstable approach which resulted in a landing with insufficient runway remaining to stop and subsequent impact with a river embankment. Contributing was the engine coolant system anomaly.

NTSB analysis

The pilot reported that after takeoff he climbed and proceeded to complete a circuit of the airport traffic pattern. While in the traffic pattern, he saw a puff of white smoke, indicative of burned coolant, near the rudder pedals and he elected to perform a precautionary landing. On approach to the runway the pilot was above the glide path but he elected to continue the approach. During the landing flare the engine lost power completely, and the airplane continued to float about ¾ of the way down the runway before touching down. As the airplane approached the end of the runway the pilot elected to force a “ground loop” to prevent the airplane from exiting the runway and going into a river.

A postaccident examination of the airplane by a Federal Aviation Administration (FAA) inspector found substantial damage to the fuselage from impact with the river embankment. The FAA inspector also noted that there was residual coolant in the cowling. The pilot reported that there was also residual coolant around the radiator cap. The pilot speculated that the automotive, rotary engine’s the rotor coolant seal may have been compromised, which allowing air from compression to enter the coolant system, and resulted in an over pressurization of this system and subsequent coolant expulsion through the radiator cap.

Text from the NTSB. Open the NTSB docket for ERA24LA355 for the full record.