On April 13, 2018, one of America’s relatively small fleet of F-22 Raptors belly flopped on the runway at Naval Air Station Fallon in Nevada. While images of the stealth fighter quickly made their way onto the internet, what exactly caused the fifth-generation fighter to end up in such a predicament has remained a mystery to the public until now.

According to a new report released by the U.S. Air Force on Monday, the F-22A, which hailed from the 90th Fighter Squadron, 3rd Wing, Joint Base Elmendorf-Richardson, Alaska, was attempting a takeoff from runway 31 Left (31L) at Naval Air Station (NAS) Fallon, Nevada at approximately 10.45 a.m. local time. The fighter was set to participate in Naval “Top Gun” exercises, in which the F-22 would be pitted against the Navy’s workhorse fourth-generation fighter, an F/A-18 Super Hornet piloted by a student.

However, as the F-22 (using the call sign, “Topgun 65”) was about to take off, the pilot apparently retracted the landing gear too early — slamming the $138 million aircraft into the ground on its belly. As the report indicates, the F-22 behaves as though it was leaving the ground before it’s actually able to, and the pilot utilized visual cues to determine that it was climbing. However, the fighter had not yet reached the necessary speed to create sufficient lift, causing it lift off the ground just slightly enough to allow the wheels to retract without tripping the weight-on-wheels sensors tied to the Flight Control System that would usually prevent such mishaps.

Immediately after main landing gear (MLG) retraction, the MA [Mishap Aircraft] settled back on the runway with the MLG doors fully closed and the nose landing gear (NLG) doors in transit. The MA impacted the runway on its underside and slid approximately 6514 feet (ft) until it came to rest 9,419 ft from the runway threshold,” the AIB report, released on Nov. 15, 2018, says.

According to the report, the incident was caused by a litany of issues, including overconfidence on the part of the pilot, a lack of training, and organizational culture.

The report concludes:

The Accident Investigation Board (AIB) President found by a preponderance of the evidence that the causes of the mishap were two procedural errors by the MP. First, the MP had incorrect Takeoff and Landing Data (TOLD) for the conditions at NAS Fallon on the day of the mishap, and more importantly, he failed to apply any corrections to the incorrect TOLD. Second, the MP prematurely retracted the LG at an airspeed that was insufficient for the MA to maintain flight. Additionally, the AIB President found by the preponderance of the evidence that four additional factors substantially contributed to the mishap: inadequate flight brief, organizational acceptance of an incorrect technique, formal training, and organizational overconfidence in equipment.