The pilot of an Air Force F-16C had just seconds to act after the plane’s engine abruptly died a minute after take-off from a New Mexico air base last year.
“Engine failure,” the pilot radioed to three other F-16s moments after a loud clap rocked his plane and left it unflyable just a thousand feet off the ground.
An Air Force report released Wednesday on the investigation of the April 2024 crash laid out the “catastrophic” mechanical failures that brought the plane down and how the pilot survived the mishap.
As the F-16’s engine rapidly lost power, the pilot spent 40 seconds looking for clues on what had gone wrong. But at less than 1,500 feet in the air, he realized there was no hope of restarting the engine and he would have to eject.
“Three’s gonna punch,” he radioed.
As his three wingmen circled overhead, they watched his ejection seat rocket free of the plane and his parachute catch in the air.
A ‘blind spot’ for engine mechanics
The final report from the Air Force formal accident investigation board pinpoints the cause of the crash as a broken fan blade in a uniquely hard-to-reach spot inside the F-16C’s engine. Notably, the report found that all the Air Force personnel at Holloman involved in the crash — the plane’s pilot, mechanics and leaders who oversee flying at the base — were blameless in the mishap.
Maintenance personnel, the report said, could not have spotted the defect before the crash, even in inspections dating back almost a decade. And on the day of the crash, the report found that the pilot — who parachuted safely to the ground — had no hope of saving the $21 million jet once a small fan blade snapped off and caused the engine to stall in the air.
“The [pilot’s] only possible favorable outcome was ejecting before running out of altitude or airspeed,” the report concluded.
The plane’s Pratt & Whitney F100-PW-220 engine sputtered and died, the report found, when a fan blade known as a variable stator vane broke free and instantly caused “catastrophic engine damage at low altitude with no ability to recover.”
The stator vane sits in the center of the F100 Engine, the Air Force’s most widely used jet engine which has powered F-16s and F-15s for decades, the report said.
The F100 produces its power by compressing and heating air through 13 separate compartments, known as stages, along its length.
Critically, the board found, the trouble occurred in the engine’s fifth stage, which — uniquely among the engine’s stages — is almost never inspected.
Maintenance crews at Holloman and other F-16 bases, the report said, routinely inspect the first four stages of the engine from the powerplant’s front, while the sixth through 13th stages are accessed from the plane’s rear. All 12 of those areas are inspected after every 100 hours of flying with special camera scopes, the report said.
But the fifth stage of the engine sits in what the report called a unique “blind spot” that mechanics at bases like Holloman cannot reach.
The engine’s fifth stage can only be accessed during “depot” level maintenance when the engine is removed from the plane and sent to Tinker Air Force Base, Oklahoma, where technicians take the engine completely apart.
The F100 in the Holloman F-16 last underwent depot-level work in 2016.
As a result, the report said, it was impossible to know when the blade inside the fifth stage was damaged. The report noted that the Holloman engine — when installed in a different plane — had ingested foreign object debris, or FOD damage, in 2022. After that incident, mechanics found no damage from the FOD in the 12 engine stages that could be reached, but no inspection was made of the fifth stage.
The board also speculated that the misaligned blade might have been installed incorrectly during the 2016 depot inspection. But engineers told the investigators that an incorrectly installed blade would not have passed a depot inspection.
In the end, the report found, the misaligned blade remains a mystery.
“I find the cause for the turned vane impossible to determine,” wrote Air Force Col. James B. Stewart, the accident investigation board’s president.
From routine flight to ejection in 109 seconds
The April 30, 2024 mishap began as a routine training sortie at Holloman for four planes in the 8th Fighter Squadron, one of three F-16 squadrons that train new Air Force pilots to fly the fighter plane in the F-16 Basic Course, or B Course. About half of the Air Force’s F-16 pilots learn to fly the plane at Holloman, where students and instructors fly about 10,800 sorties each year to qualify about 180 fighter pilots.
The F-16’s pilot was a B Course instructor with 700 flight hours. The jet was the third plane in a formation of four F-16s flying together on a morning training flight. Instructors in two of the planes would each fly alongside a student in another jet, grading them in simulated attacks on ground targets.
Nothing about the morning flight was out of order, the report noted.
“The pilot was current, qualified, medically fit, and performed appropriate actions,” the report noted, and the same was true for the plane and the mechanics who took care of it. The jet had no pending maintenance issues and the crew chiefs who launched the plane did their jobs correctly.
“The scheduled mission was supervised correctly and released by pertinent authorities,” the report found.
Even the weather, the report said, was great: “clear skies with unrestricted visibility and light winds.“
According to the report’s narrative of the crash, the four planes took off from Holloman’s Runway 25 under full afterburner, spaced out by 15 seconds, then cut back their engines when they reached 300 knots, flying in shallow left turns towards the desert ranges of White Sands National Park.
But trouble struck the third jet almost immediately.
Just 33 seconds after its wheels left the ground, as it reached 1,000 feet in altitude, the pilot heard “a loud bang and felt a loss of thrust, violent shaking, and engine vibrations.”
The pilot rolled the jet out into a straight heading to begin to process what had just happened and radioed to his flight to “knock it off” — an emergency phrase to cease training because of a problem.
But within seconds, the pilot realized his engine was dying, and the plane would quickly crash without it.
Just 105 seconds after taking off, the pilot announced he was “gonna punch” and four seconds later he rocketed upwards in his ejection seat as the plane traveled at 156 knots
Because of the low altitude, sensors in the ejection seat automatically deployed the pilot’s parachute as soon as he ejected.
As the pilot floated to the ground, sore but largely unhurt, his two-minute run of bad luck finally began to change.
Flying on an unrelated training mission nearby was a flight of Army helicopters. On board one was a flight surgeon. Circling above, the remaining F-16 instructor directed the Army flight toward the parachute’s landing spot and the helicopters reached the Air Force pilot less than five minutes after he landed.
After a quick check from the flight surgeon, the report said, the pilot walked to the helicopter.