The Air Force Thunderbirds pilot killed in April when his F-16 crashed during a training flight in Nevada lost consciousness during a strenuous maneuver moments before impact, according to a service investigation into the wreck.
Maj. Stephen Del Bagno “became completely incapacitated for a period” as he practiced the “High Bomb Burst Rejoin” maneuver alongside five other Thunderbirds pilots April 4 at the Nevada Test and Training Range near Las Vegas, according to Air Combat Command, which released the investigation Tuesday. In that maneuver, four Thunderbirds jets fly together straight up in the air in a diamond formation before darting in opposite directions at high speed.
Though Del Bagno was able to recover slightly, he never made an attempt to eject from the aircraft, according to investigators.
Del Bagno, 34, was training for his first season with the Thunderbirds, the Air Force’s squadron of elite fliers who tour the country providing aerial demonstrations to the public. He was a longtime pilot who went by the call sign “Cajun.” He had most recently spent nearly three years flying F-35A Lightning II stealth fighters in Florida as part of an evaluation and instruction team.
Though the squadron had experienced three crashes in recent years, Del Bagno was the unit’s first flying in death since 1982.
The Thunderbirds canceled several planned show at the beginning of their 2018 season, but they resumed flying in May.
During the training flight, Del Bagno flew inverted for some 22 seconds at an altitude between 5,500 and 5,700 feet, experiencing gravitational force, or g-force, at about a negative two before beginning a Split-S, or half loop, maneuver that rapidly took him to a g-force of more than 8.5, according to the 32-page investigators’ report.
At that point, he lost consciousness, investigators concluded, noting Del Bagno made no attempts to control the plane until about one second before impact.
Two main factors contributed to the crash, according to the report. The first was the “push-pull effect” of moving from the negative g-force — the impact of gravity on the body upside — to the extremely strenuous g-force of 8.56, or more than 8.5 times the normal pull of gravity on the body, which forced Del Bagno unconscious. Secondly, investigators determined the diminished tolerance to the high g-force contributed to his inability to perform maneuvers that help pilots’ bodies counter those forces, called anti-g-force straining maneuvers.
Investigators found no evidence that Del Bagno’s physical fitness level played any part in losing consciousness. It also determined his F-16 was in proper flying condition with no reported maintenance deficiencies that would have contributed to the crash.
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