Incident Description
A student pilot stated that during the takeoff roll, she heard a popping sound. Almost immediately afterward, the aircraft door came open. The pilot attempted to close the door, but when that was unsuccessful, she decided to abort the takeoff. She reduced the throttle and attempted to apply braking. However, the braking was not effective, and the aircraft departed the side of the runway and traveled down an embankment.
Examination Findings
An examination of the wreckage, conducted by the operator, determined that the popping sound the pilot heard was caused by the pilot's seat belt striking the outside of the pilot's door. The seat belt had been banging against the door during the takeoff roll.
Further inspection of the brake system did not reveal any evidence that would explain the pilot's report of a brake deficiency. The reason for the ineffective braking was not identified in the examination.