What happened
The pilot was operating a flight from Fairbanks to Kantishna, Alaska. Upon arrival at the destination, the runway conditions were muddy, prompting the decision to return to Fairbanks. During the return leg, the pilot elected to land at an abandoned mine strip for a comfort stop.
During the landing roll, a hydraulic line supplying the right brake failed, rendering that brake inoperative. To avoid a head-on collision with an embankment, the pilot intentionally ground looped the aircraft. The tail section struck the embankment, resulting in substantial damage to the airframe.
The pilot reported that the hydraulic line had been leaking prior to takeoff and that he had attempted to tighten the fitting. He stated that the flared end of the rigid line failed, causing a rapid loss of pressure.
The investigation
Examination of the aircraft revealed that the hydraulic line to the right brake had failed. The pilot indicated that the line was leaking before departure and that he had tightened the fitting. The failure occurred at the flared end of the rigid line, which permitted a rapid loss of hydraulic pressure.
Findings
- Hydraulic system failure due to a failed flared end on a rigid line.
- Inoperative right brake during the landing roll.
- Substantial damage to the aircraft tail section from striking an embankment.
- Pilot-initiated ground loop to avoid collision with terrain.