Just days before a Super Stallion helicopter crashed in the Gulf of Aden, on Sept. 1, 2014, a Marine maintenance crew was sent ashore to do some repair work on the aircraft, to replace a broken engine.
A Marine Corps investigation has found
that some maintenance decisions before the mishap “deviated from established standards,” but the repair work was ultimately not to blame for the engine failure.
Nobody was disciplined in the aftermath.
The investigation, however, could not answer the key question: What caused the catastrophic failure of the Super Stallion’s No. 2 engine?
What officials do know is that one of the engines that failed during that flight has been a “persistent problem” on this type of aircraft for years.
The Super Stallion, which is primarily used to move cargo and Marines, is one of the military’s most powerful heavy-lift helicopters. It’s also one of the most “maintenance-intensive” aircrafts in the fleet, requiring “more than 35 hours of work” on the ground for every hour in the sky, according to officials.
Having entered service in the early 1980s, it’s also among the oldest. Despite the issues reported, the Super Stallion is expected to remain in service through at least 2025. The military has hired the aircraft’s manufacturer, Sikorsky Aircraft Corp., a half dozen times since the early 1990s to study problems with its design.
The majority of Super Stallion and Sea Dragon engine failures are due to foreign-object damage, the report stated.
In response to past engine failures, the military several years ago equipped the helicopters with sensors to warn pilots when the No. 2 engine is overheating, in theory giving them time to shut it down and land.
The Super Stallion has been under intense scrutiny lately. According to hamptonroads.com, officials ordered intensive inspections to “find and replace chafing fuel lines and wires” in every Super Stallion and Sea Dragon. Investigators pointed to that mechanical defect as the cause of a deadly crash off the coast of Virginia last year.
In the September 1, 2014 incident off the coast of Djibouti, several of the Marines and sailors were disoriented while trying to get free of the sinking aircraft. One said he vomited repeatedly after inhaling helicopter fuel. All 25 Marines and sailors were recovered by inflatable boats sent from the USS Mesa Verde to get them — according to documents obtained by the Washington Post.
The Super Stallion was never recovered. It sank more than 4,000 feet in the Gulf of Aden. It would have cost about $8 million to retrieve it. So, the mechanical cause will never be known and it’s now known whether the engine failure was related to past problems.