US air force finds two causes in death of contractor who walked into propeller

A US air force civilian contractor had become disoriented recording data at an airport in California last year when she walked into a jet’s rotating propeller and was killed, officials said Friday.

In a statement outlining the findings of a report into the contractor’s death, the air force materiel command said that 32-year-old Stephanie Cosme was mortally injured on 7 September when she inadvertently walked into the rotating propeller of an MQ-9A that was parked at Gray Butte airfield.

Related: US military names five marines killed in California helicopter crash

The report described the MQ-9A as an “armed, multi-mission, medium-altitude, long-endurance remotely piloted aircraft that is employed primarily against dynamic execution targets and secondarily as an intelligence collection asset”.

At the time she was killed, Cosme was employed by Sumaria Systems and was providing test support services for the air force’s Life Cycle Management center, one of six centers reporting to the air force materiel command.

In its findings, the air force materiel command accident investigation board said it found two causes for the incident.

“First,” the board said, “the test engineer was incorrectly instructed or trained on how to take telemetry readings when approaching the MQ-9A while the engine was running. Second, she lost situational awareness while walking around the mishap aircraft taking telemetry readings with a hand-held measurement device.”

The report said that Cosme “was looking down at the testing device the whole time, and appeared to be pressing buttons, possibly to keep the backlight on”. It added that someone began walking towards Cosme, “shouting and waving his arms in an attempt to get [her] attention”.

“Others began shouting and waving to get [Cosme’s] attention as well,” the report said. It added: “Without looking up to determine her position relative to the aircraft, [Cosme] proceeded to walk directly into the propeller … sustaining fatal injuries.”

In its statement, the air force materiel command revealed two factors that “substantially contributed” to Cosme’s death, including a clear lack of communication among the contractor test team and ground support personnel, as well as rushed tests that were conducted on that day due to previous delays and cancellations.

It also said the investigation board conducted a simulation recreating Cosme’s deadly mishap, and that the spinning propeller was not visible when looking at the rear of the aircraft from where she approached.

Cosme’s survivors include her parents, two siblings, a fiance and a stepdaughter.

Her Legacy.com obituary says “family was the center of Stephanie’s world”.

“She was known for her passion for crafting, baking, aviation and all things strange and unusual,” the obituary said. “Whether she was planning a party or working on an art project, she approached everything she did with dedication and enthusiasm, leaving a lasting impact on those she encountered.”