Several compressor vanes, turned out of position in the fourth and fifth stages of a Pratt & Whitney F100-PW-229 engine, cost the Air Force Thunderbirds an F-16CM. Air Force accident investigators concluded that the misaligned vanes set off a chain of blade failures that left the jet without enough thrust to stay airborne. The pilot ejected and survived with minor injuries; the aircraft, valued at $33.46 million, was a total loss.
The jet, serial 92-3881, went down on Dec. 3, 2025, crashing into a lakebed near Trona, California, during a training sortie. The Accident Investigation Board’s report was completed on Sept. 1, 2026, and released publicly on Sept. 21, 2026.
The board’s findings were laid out by The Aviationist in a Sept. 25, 2026 report by Parth Satam, which quotes the investigation directly. Details of the sequence and the findings below are as The Aviationist reported them unless another source is named.
A stall during a formation rejoin
The planned mission was to fly “loops and rolls” in a “Delta formation,” according to The Aviationist’s reading of the report. The mishap aircraft broke away as planned with a 360-degree right turn and was rejoining the formation when the engine stalled in a way the pilot could not recover from.
At low altitude and without enough thrust to hold level flight, the pilot tried to climb toward an alternate airfield. Switching the engine to its Secondary Engine Control caused fuel flow to spike, and the engine flamed out. The pilot switched back to primary control and restarted it, but the report found the thrust it produced was insufficient to sustain flight. The ejection came about 4 minutes and 21 seconds after the initial stall.
The 57th Wing at Nellis Air Force Base, home of the U.S. Air Force Air Demonstration Squadron, gave the first official account on the day of the crash. As quoted by The War Zone on Dec. 3, 2025, the wing said that at approximately 10:45 a.m. “a Thunderbird pilot safely ejected from a F-16C Fighting Falcon aircraft during a training mission over controlled airspace in California,” and that the pilot was in stable condition.
Inside the F100’s high-pressure compressor
The vanes in question sit in the engine’s high-pressure compressor, and turned vanes disrupt the airflow that reaches the blade stages behind them, in The Aviationist’s summary of the findings. The board found that “multiple vanes were turned at several locations along the 4th and 5th stages of the HPC,” according to The Aviationist.
The damage then cascaded. Per the report as quoted, “single blade separations occurred at its 5th and 6th stages, resulting in subsequent damage through the 7th stage.” Task & Purpose, in its coverage of the report’s release, described the finding as three misaligned, or turned, variable vanes in the 4th and 5th stages, and named the board president as Col. J.C. Brooks.
The engine type has a long service record. Pratt & Whitney’s F100 product page calls it the engine of choice for the F-15 and F-16 and says more than 3,800 F100 engines are in service with 23 air forces, with more than 30 million flight hours flown.
Why an inspection could not catch it
The board did not pin down how the vanes were turned. The Aviationist reports that investigators concluded it was impossible to conclusively determine the cause of the turning, and that the engine had last been inspected during a 50-hour inspection on Oct. 1, 2025, with no defects noted.
That inspection could not have reached the damage. The board found that the inability to inspect the affected compressor stages “without removing the engine from the aircraft and opening the rear compressor case” substantially contributed to the mishap. Task & Purpose characterized those stages as a blind spot, reporting that they can be checked only during major overhauls.
The Accident Investigation Board’s finding, released on Sept. 21, 2026, closes the public record on the loss of aircraft 92-3881: turned vanes, a cascading compressor failure, a successful ejection, and $33.46 million in hardware written off.
Top image: Two U.S. Air Force Thunderbirds F-16s fly the mirror-image maneuver in 2014. Not the aircraft lost on Dec. 3, 2025. Image Credit: U.S. Air Force photo by Staff Sgt. Brandon Shapiro — Public domain / Wikimedia Commons
This article was produced with the assistance of AI and reviewed by Combat Rated editors prior to publication.