A Valencia pilot who flew for the U.S. Air Force’s Thunderbirds lost consciousness during a training flight just before fatally crashing in April, according to an Air Force investigation. The report, released this week, found that Major Stephen Del Bagno, a Saugus High School graduate, experienced a high G-force maneuver and was incapacitated for five seconds just before the impact. He was conducting a routine Thunderbirds aerial demonstration in his F-16 Fighting Falcon at the Nevada Test and Training Range. An air demonstration, with up to eight pilots, is a mix of formation flying and solo routines. During what’s called the “High Bomb Burst Rejoin,” a routine conducted toward the end of the demonstration, Del Bagno flew for about 22 seconds in inverted flight at more than 5,500 feet above the ground. The pilot then experienced “a change in force due to acceleration measured in multiples of the acceleration of gravity felt at the earth’s surface,” or minus-2 Gs, and the aircraft began to descend in a half-loop maneuver called the Split-S. At that point, the report read, Del Bagno reached a maximum of 8.56 Gs after five seconds in the Split-S and lost consciousness. Just before crashing to the ground, he recovered and attempted to control his F-16CM but was unsuccessful. “(Del Bagno) impacted the ground at 57 degrees nose low with 89 degrees of left bank and the MP was fatally injured on impact, without an ejection attempt,” the report read. The Accident Investigation Board determined that the “pull-push effect” of switching from minus-2 Gs to more than 8 Gs significantly diminished his tolerance of G-forces, affecting his ability to maneuver the aircraft. No issues with the plane or other health conditions were found before takeoff, the report said. In April, Brig. Gen. Jeannie Leavitt, 57th Wing commander, said in a statement posted on the Thunderbirds website that the pilot “was an integral part of our team and our hearts are heavy with his loss.” Del Bagno logged more than 3,500 total flight hours in over 30 different aircraft, with 1,400 hours as an Air Force pilot. He was a 2005 graduate of Utah Valley State University and in 2007 he commissioned from Officer Training School, Maxwell AFB, Alabama. Before joining the Air Force, he was a civilian flight instructor, corporate pilot, skywriter and a banner tow pilot. He enjoyed snowboarding, water sports and spending time with family and friends.