The pilot of a Duke Life Flight medical helicopter that crashed in northeast North Carolina more than three years ago, killing all four people aboard, likely got confused by an array of emergency indicators about a problem with one of his two engines and mistakenly shut down the other one, according to federal investigators.
The helicopter, which was based at Johnston Regional Airport in Smithfield, was en route to Duke University Hospital in Durham from Sentara Albemarle Medical Center in Elizabeth City on Sept. 8, 2017, when it crashed in a grassy field outside the town of Belvidere, south of the Perquimans-Gates county line, officials said.
Pilot Jeff Burke, flight nurses Kris Harrison and Crystal Sollinger and patient Mary Bartlett were killed.
In their final report on the crash, which was released last month, National Transportation Safety Board investigators said damaged roller bearings in the No. 2 engine likely caused the engine to malfunction during flight.
Because investigators couldn't recover any recorded data from the flight – the battery on a recorder installed on the aircraft may have died, according to the report – they said they couldn't know exactly which indicators went off and in what sequence. But they said Burke likely misread his instruments and believed he was losing power from the No. 1 engine, prompting him to shut it down.
"A failure of the rear bearing in the No. 2 engine ... created multiple and likely unexpected and confusing co*ckpit indications, resulting in the pilot's improper diagnosis and subsequent erroneous shutdown of the No. 1 engine," the report states.
The damaged No. 2 engine then likely lost all power, according to the report, and the wreckage "indicated that the helicopter was in a near-vertical descent before impacting the ground."
"[T]he helicopter would have been able to fly to a suitable landing location with only one engine operative," the report states. "However, the helicopter would not have been able to hover to land, which would have required the pilot to make a running landing onto a smooth, firm surface."
NTSB investigators couldn't determine the reason why the No. 2 engine failed because of a combination of damage from its continued operation and the crash, as well as a subsequent fire.
Witnesses told investigators that they saw a trail of dark smoke coming from the helicopter before the crash, but the NTSB couldn't determine if the No. 2 engine was on fire during flight.
Investigators also noted that metallic contaminants were found in oil from the No. 2 engine during routine tests in the months before the crash, indicating a potential bearing failure. But the amount of contamination never rose to the level specified by the engine manufacturer to warrant action.
"The oil test evaluation procedures did not include steps to monitor trends of contaminant concentration levels over time. If the engine manufacturer’s procedures had included appropriate trend monitoring criteria, the impending bearing failure in the No. 2 engine might have been detected and mitigated," the report states.
The helicopter had its last scheduled maintenance a week before the crash.
The families of all four victims have filed lawsuits against the helicopter's manufacturer, Airbus, and the engine maker, Safran. All of them aside from Burke's family also have sued the aircraft's operator, Air Methods. The lawsuits focus on the engine failure, the confusing instrumentation during an emergency, the operation of the aircraft and maintenance.
WRAL anchor/reporter Cullen Browder contributed to this report.
