According to an Air Force inquiry, a damaged engine part caused the devastating fire that destroyed a B-1 Lancer bomber this spring, costing $15 million.
The 7th Aircraft Maintenance Squadron at Dyess Air Force Base, Texas, was running the bomber's jet engine while replacing its hydraulics on April 20, according to an accident report approved Dec. 19.
The maintenance check failed due to a crack in the engine's disk, which holds the fan blades. After publishing the report, the Air Force did not announce it.
Air Force Times reviewed the report Friday. At 2 p.m. local time, B-1 pilots noticed a potential problem with one of the plane's four engines when a nozzle that should have fully opened was still closed during "hot refueling."
Propulsion specialists were summoned. Lancers use four General Electric F-101-GE-102 engines.
The report stated, “When the... pilots moved the #1 engine throttle to intermediate power, [its] nozzle... returned to its correct open position when the throttle was returned to idle.”
“Satisfied that the issue was rectified, the propulsion specialists departed.”
However, the nozzle closed again shortly after. A propulsion control component defect was suspected by one specialist.
That was disproven.
The component failed due to hydraulic system issues, which they fixed at 10 p.m.
According to the Air Force report, “The [aircraft] then required a maintenance engine augmenter run... to check proper operations of the engine hydraulic pump and to ensure it did not leak fluid.”
After training with the Japanese Air Self-Defense Force at Dyess Air Force Base, Texas, a B-1B Lancer taxis on the flightline.
(Air Force/Airman 1st Class Ryan Hayman) The Dyess fire chief provides additional facts on last month's catastrophic B-1B bomber fire.
When fire firefighters arrived, flames on the bomber's left side reached 75 feet. Cohen, Rachel S.
After 30 minutes, the engine ran nicely again. A warning light illuminated. The jet's left side caught fire.
Engine pieces were thrown 1,000 feet distant by 200-foot flames. One airman's right leg was injured by hot shrapnel. Airmen shut down the engine and firefighters arrived.
A local hospital treated the injured man and advised a week of recuperation at home.
The Air Force reported that another injured airman was treated and released from a nearby hospital.
The plane's skin and metal components melted where the left wing joined the bomber's fuselage.
According to the report, it burned vital mechanical, electrical, and hydraulic components.
According to the report, the malfunctioning fan disk broke at an unknown time.
The engine was recently refurbished in 2017 and could fly for much longer until its next substantial maintenance, according to the report.
It was shipped from South Dakota to Dyess in April 2021 to patch an oil leak and reinstalled on the B-1 that would catch fire months later.
According to the assessment, the fan disk had used 25% of its anticipated service life.
However, "high-cycle fatigue" caused by plane acceleration and deceleration wore the metal.
That shattered the disk, which deformed to approximately 1 inch deep.
When it failed, it punched a hole in the B-1's engine, destroying other parts and sparking sky-high flames.
Red Flag 22-2 at Dyess Air Force Base, Texas, March 3, 2022, features a B-1B Lancer taxiing on the runway. Reilly McGuire/Air Force Senior Airman B-1B bomber fires at Dyess, injuring two.
Two people were treated for non-life-threatening injuries at a local hospital and released. Cohen, Rachel S.
According to the findings, human error did not cause the mishap. The airmen were competent and following maintenance procedures.
After the crash, the report did not specify what happened to the roasted airframe. The Air Force is retiring 40 B-1Bs, which do not carry nuclear missiles. In 1998, it used its first B-1B to fight Iraq. The planes are based at Ellsworth AFB and Dyess.
B-1Bs have had ejection seat and fuel tank concerns. In 2018, a Lancer crew of four awarded the Distinguished Flying Cross after landing their aircraft with a burning wing.
Due to plane downtime, the fleet's readiness rates are low.
In the weeks before the crash, investigators found that less than 70% of the 7th Bomb Wing's B-1s could complete at least one basic mission.
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