Diamond Aircraft DA 40 N489RS accident near Portsmouth, New Hampshire

Probable cause

The instructor’s multiple applications of the airplane’s brakes during high-speed taxi over a short duration, which overheated and ignited the right main landing gear wheel brake assembly.

NTSB analysis

After landing, the flight instructor assumed control of the airplane during the roll, taxied to the hold-short line at the approach end of the runway, and waited for landing traffic. Soon after, the pilot of the landing airplane announced over the tower radio frequency that the airplane holding short was “on fire.” The instructor confirmed that smoke was rising from beneath the right wing and both he and the pilot receiving instruction egressed the airplane without injury.

Examination of video revealed fire emanating from the right main landing gear wheel and brake assembly, wheel pant, and involved the right wing, which was substantially damaged.

Data downloaded from the airplane’s multifunction display revealed high groundspeeds during taxi after landing, and rapid decelerations consistent with hard braking actions before the airplane reached the hold short line. Postaccident examination revealed normal wear of the brake pads and no pre-accident mechanical anomalies. Examination of the fuel cell directly above the right main landing gear wheel and brake assembly revealed that it was intact with no leaks and contained about 15 gallons of fuel. Based on the available evidence, it is likely that the instructor’s high taxi speeds, which required multiple brake applications, resulted in the right brake assembly overheating and catching fire.

Text from the NTSB. Open the NTSB docket for ERA21LA099 for the full record.