Drone Propeller Claims Life of Air Force Contractor: Investigation Reveals Lack of Communication

An Air Force civilian contractor, Stephanie Cosme, tragically lost her life on September 7, 2023, when she walked into the moving propeller of an MQ-9 drone at Gray Butte Airfield in California. The final accident investigation report by Air Force Materiel Command revealed that Cosme’s death was due to her losing situational awareness and supervisors skipping crucial parts of the safety briefing in a rush to complete testing, according to Task and Purpose.

Lack of Communication and Improper Training

The report found that the situation worsened due to a “clear lack of communication among the test team and ground support personnel.” Cosme, who was working for Sumaria Systems LLC, a contractor hired by the Air Force, “was incorrectly instructed or trained on how to take telemetry readings when approaching the MQ-9A while the engine was running,” according to a statement from Air Force Material Command.

Rushing to Complete Tests

Ground crews were rushing to complete their tests following a dry run on September 6. As a result, the mission and safety briefing on September 7 skipped several steps, including crucial parts about emergency procedures and what the AIB called “aircraft keep out zones.”

Attempts to Warn Cosme

While conducting tests on a hand-held device near the MQ-9 drone, Cosme got dangerously close to the aircraft without noticing. Other members of the test crew noticed her walking toward danger and tried to wave her down, but were unable to reach her before she walked into the spinning propeller.

Simulation Reveals Visibility Issues

As part of its investigation, the AIB staged a simulation of the conditions and layout at Gray Butte Airfield on the night of the incident. Investigators found that “the spinning propeller was not visible when looking to the rear of the aircraft from the trailing edge of the right wing.”

Remembering Stephanie Cosme

Stephanie Cosme, who was 32 at the time of her death, is survived by her parents, two siblings, a fiance, and a stepdaughter. Her obituary shared on Legacy.com states, “Throughout her life, Stephanie touched the hearts of everyone she encountered with her warmth, kindness, and unwavering love. She had an innate ability to make those around her feel special and valued. Her capacity to love and care for others knew no bounds. Her gentle spirit and radiant smile brought comfort and joy to all who had the privilege of knowing her.”

The tragic death of Stephanie Cosme serves as a reminder of the importance of proper safety briefings, clear communication, and maintaining situational awareness in high-risk work environments. The Air Force Materiel Command’s accident investigation report highlights the need for contractors and military personnel to prioritize safety protocols and ensure that all team members are adequately trained and informed to prevent such devastating accidents from occurring in the future.

Photo courtesy of Wikipedia.


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Haye Kesteloo
Haye Kesteloo

Haye Kesteloo is a leading drone industry expert and Editor in Chief of DroneXL.co and EVXL.co, where he covers drone technology, industry developments, and electric mobility trends. With over nine years of specialized coverage in unmanned aerial systems, his insights have been featured in The New York Times, The Financial Times, and cited by The Brookings Institute, Foreign Policy, Politico and others.

Before founding DroneXL.co, Kesteloo built his expertise at DroneDJ. He currently co-hosts the PiXL Drone Show on YouTube and podcast platforms, sharing industry insights with a global audience. His reporting has influenced policy discussions and been referenced in federal documents, establishing him as an authoritative voice in drone technology and regulation. He can be reached at haye @ dronexl.co or @hayekesteloo.

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