The Air Force on Tuesday released an accident investigation board report determining the cause of a fatal F-16 Thunderbird crash this past April.

Maj. Stephen Del Bagno, an F-16CM pilot assigned to the Thunderbird squadron, fatally crashed after suffering loss of consciousness while performing in a routine aerial demonstration training flight April 4 at the Nevada Test and Training Range (NTTR) near Creech Air Force Base, Nevada, the board determined.

A U.S. Air Force F-16. Photo: Air Force.
A U.S. Air Force F-16. Photo: Air Force.

The mishap took place during a practice of the ‘High Show’ version of the Thunderbirds aerial demonstration in the south part of the NTTR,” according to an Air Force statement issued Oct. 16. “During the ‘High Bomb Burst Rejoin’ maneuver near the scheduled end of the aerial demonstration training flight, the pilot spent approximately 22 seconds in inverted flight between 5,500 and 5,700 feet above the ground level. After transitioning into a descending half-loop maneuver (Split-S) the pilot experienced a gravity induced loss of consciousness (G-LOC), became completely incapacitated for a period, and was fatally injured on impact without an ejection attempt.”

Del Bagno was incapacitated for about five seconds, and made “no deliberate flight control inputs” as the aircraft headed toward the ground, the report said. About one second before impact, the pilot began to work the controls again.

The pilot’s gravity-induced loss of consciousness was determined to be the main cause of the mishap, the report said.

Del Bagno was a qualified aerial demonstration pilot with training dated back to 2008 with more than 500 flight hours in the F-16. The report states that he completed the High Bomb Burst Rejoin maneuver 29 times without incident prior to the mishap.

The accident investigation board review was conducted by analysis of available flight data, the crash report performed by F-16 manufacturer Lockheed Martin [LMT], mishap animation technology, witness testimony, engineering analysis, and academic research on human factors, the report said. The Thunderbirds will incorporate the findings of this report into future procedures and process improvements, a statement by Air Combat Command said.