Investigators have determined that a series of of “missteps, oversights and miscalculations” led to the fatal Marine chopper crash right outside Twentynine Palms in California, on Jan 23.
The two Marine pilots on board who were killed — Maj. Elizabeth Kealey, and Capt. Adam Satterfield– were taking the 49-minute flight from their home base in Camp Pendleton to participate in an exercise with the rest of their squadron, at the Marine Corps Air Ground Combat Center.
According to the accident report, the aircraft plummeted 200 feet, just 400 yards away from the Marines’ intended landing spot. The UH-1Y Venom helicopter fell vertically, slamming into the ground right-side-up. The aircraft then rolled to its right side, and members of a Marine squadron working in a hangar just 1,000 feet away, rushed to the scene to try to save the victims.
Both pilots were transported to local hospitals ,where they later died. Kealey was a captain at the time and Satterfield a first lieutenant. The two were posthumously promoted during a February ceremony, Marine Corps Times reports.
While the investigation found that pilot error and improper aircraft maintenance were factors in the crash, the investigating officer wrote: “I do not believe there should be any punitive action taken against any members of HMLA-169,” referring to Marine Light Attack Squadron 169.
About 34 minutes into the short flight, the pilots noticed that their oil pressure gauge fluctuated and then “plummeted to zero.” The warning lights usually indicate an emergency, but because the pilots didn’t try to land at two other nearby airports – on the way to Twentynine Palms- they must have assumed the problem was due to a faulty gauge, not actual fluid loss.
“This is indicative of a pilot who thinks they have an instrument indication problem, not one that has a full-blown emergency on their hands,” the investigating officer wrote.
At that point their intended destination was more than 15 minutes away, however “Loss of MRGB oil pressure will render the helicopter unflyable within 15 minutes,” the aircraft’s Naval Air Training and Operating Procedures Standardization manual states.
A maintenance error involving a faulty filter cover is at the heart of this tragedy too. A new filter cover, which was “improperly installed” three days before the deadly crash, leaked or came off in flight.
However, the “root cause” of the trouble with the filter was a maintenance error made “long before the accident.” The filter housing must be uninstalled to change the filter. But the Times reports that “at some point, an unapproved epoxy was used to seal the filter body, preventing Marines from removing it.”
Three waivers were issued over months to go without a filter change. A post-crash investigation supported an earlier assumption that it was “unlikely the filter was dirty.” So, the filter itself was not a contributing factor. “However, during one failed attempt to change the filter while it was still installed in the aircraft, the cover was damaged,” the article said.
When three Marines worked to install a new cover on Jan. 20, they apparently did not realize that a retaining ring that holds the cover on was not seated properly.
That ultimately led to massive fluid loss during flight, investigators concluded.
While investigators did find “oversights in judgment in various areas that do need to be addressed through mentoring and leadership,” they did not find any negligence.