Incident Overview
A pilot conducting a night takeoff experienced an unexpected event when the cockpit entrance door opened during the initial phase of the departure. Unable to close the door, the pilot decided to abort the takeoff. However, during the attempt to stop the airplane, the brakes did not function properly, according to the pilot's account.
Sequence of Events
The airplane continued beyond the departure end of the runway and subsequently collided with trees and fence posts. The pilot reported that the brakes were ineffective in bringing the aircraft to a halt before the runway ended.
Investigation Findings
An on-scene investigation of the aircraft's hydraulic system revealed that it was mechanically sound. However, the brake system hydraulic fluid reservoir was found empty of fluid. Investigators noted a lack of evidence indicating any leakage of brake fluid on the airframe or landing gear legs.
Conclusion
The events leading to the runway excursion involved a combination of an open cockpit door and brake system failure. The exact cause of the empty brake fluid reservoir could not be determined from the available evidence.