Flight Details
The flight was conducting a practice nondirectional beacon (NDB) approach to runway 34 at Great Falls under visual meteorological conditions. While abeam the final approach fix, the aircraft was observed 4 miles right of course. After being advised by ATC, the pilot corrected back to the final approach course using a 60-degree intercept angle and subsequently rolled out on course approximately 3 miles from the runway.
ATC Communications
The pilot then called for a missed approach. In response, a local controller who was a trainee instructed the pilot to execute a 360-degree right turn to enter a right downwind for runway 3. The pilot acknowledged this instruction. Shortly thereafter, the controller trainee amended the instruction to a 180-degree right turn to enter a right downwind for runway 21, then further amended it to a 180-degree right turn to enter a right downwind for runway 3. The crew did not acknowledge the amended instructions.
Collision Sequence
Controllers subsequently observed that the aircraft had crashed. Witnesses reported that the airplane entered a steep descent from a right turn and impacted the ground at a steep angle.
Investigation Findings
Investigators found no evidence of any aircraft malfunctions. The flight was described as recurrent training required by the owner's insurance. However, the second occupant of the aircraft—who held an airline transport pilot and flight instructor certificate—had those certificates revoked and was operating with only a private pilot certificate at the time of the accident.
The probable cause, as determined by the official investigation, was the flight crew's failure to maintain aircraft control.