MINOT AIR FORCE BASE, N.D. — A catastrophic engine failure is the likely cause of a Jan. 4 incident in which a B-52 lost one of its eight engines, top Air Force leaders confirmed to Defense News on Thursday.



A Boeing B-52 Stratofortress assigned to Minot Air Force Base's 5th Bomb Wing was conducting a training mission over North Dakota when one of its Pratt & Whitney TF33-P-3/103 turbofan engines fell from the plane, the service confirmed late Wednesday. The pilots were able to land the plane safely, with no injury to the five-person crew.



The Air Force continues to investigate the root cause of the mishap, but it appears that the engine began breaking down from the inside, eventually cracking the protective casing around it and detaching from the plane, Air Force Secretary Deborah Lee James said in an exclusive interview.



In a separate interview at Minot Air Force Base that morning, head of Air Force Global Strike Command Gen. Robin Rand offered a similar assessment."The engine didn't just fall off. The engine had a failure inside the engine, and it shelled itself," he said.



The B-52's eight TF33s are mounted under the wings of the bomber, in pods of two engines encased by the protective structure called the "cowling." Initial evidence suggests the engine was not lost as a result of being improperly mounted. Rather, it's likely that an internal problem with one of the engines could have caused the cowling to begin crumbling apart, Rand said.



"But we don't know why yet, and I won't know" until the investigation concludes, he said.



An Air Force spokesperson also confirmed to Defense News that the "leading edge" of the wing and cowling of two other engines were damaged as a result of the mishap.



The B-52 impacted by the engine problems was manufactured in 1961, but the engine has cycled through many rounds of overhauls since then, Rand said. "This engine had its last extensive work only 300 hours of flying time [ago]. … It's not like an engine that has been on the aircraft since 1961."



A UH-1N Huey on Wednesday found the wreckage of the engine in a riverbed about 25 nautical miles northeast of Minot AFB. But the service has not solidified when and how it will collect it, Rand said, adding that "recovery is going to be a challenge."





Rand is a strong proponent for replacing the Stratofortress’ engines but made it clear that Wednesday’s mishap should not be used as the justification for procuring new propulsion systems.

"Unfortunately in the aviation business there are failures. Structural, mechanical things fail, and that's what I want to chalk yesterday up to, and there's no evidence that would support otherwise that there's now a systemic problem with the safety of our engines," he said.

"Re-engining the B-52s makes sense from an operational and an efficiency [standpoint] because there is better technology today than there was when we made the B-52s," he said. "It would reduce the time maintenance [personnel] has to spend on working an airplane. It would reduce fuel costs and the amount of fuel that is consumed, because these engines are just better technology. So over the course of decades there would be a lot of savings that would be gained."

The problem, Rand said, is the cost, which the Air Force estimates as at least $5 billion to $7 billion.

Global Strike Command is working with the service’s acquisition wing to look at alternate payment options that would prevent it from having to procure the engines upfront, such as leasing the systems or a public-private partnership. Some of those options could require congressional approval, said James, who added that the service should further explore the possibilities.

"There could well be a business case to be made that re-engining could become a longer-term investment to the American taxpayer," she said.

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The Air Force in its 2017 budget did not allocate any funds for the re-engining effort, "however we are actively evaluating options for future years and remain committed to keeping the B-52 safe and combat-mission ready," said service spokesman Capt. Michael Hertzog.

The 2018 budget plans currently do not include funding for re-engining the inventory of 78 B-52s, although the next administration could make changes, James said.

As much as Rand acknowledged that he would like to see the B-52s get new engines, he said that the service will have to weigh that need against priorities in combat aviation, space, cyber and other missions.