What happened
During the takeoff roll, the aircraft began to veer left of the runway centerline. In an attempt to correct the deviation, the pilot applied the right brake, but there was no response from the braking system. The pilot then attempted to regain directional control by applying throttle to utilize tail rudder control; however, this maneuver proved ineffective.
The aircraft continued to veer off the runway and descended down an embankment. As the aircraft tipped over the edge of the embankment, the pilot's knee inadvertently pushed the throttle forward, providing a burst of engine power. This surge of power contributed to the aircraft continuing down the embankment until it ultimately nosed over.
The investigation
An on-scene investigation revealed that there was no brake fluid present in the right brake reservoir. Despite the lack of fluid, investigators found no evidence of leakage throughout the brake system, and an examination of the brake system did not reveal any mechanical anomalies.
The pilot reported that a brake check had been performed prior to takeoff, during which no malfunctions were observed. At the time of the accident, the aircraft had been operated for 153 hours since its last annual inspection, which had occurred 11 months earlier.