Overview
On 7 September 2023, at approximately 7:57:57 p.m. local time, a contractor test engineer (MTE1) came into contact with the propeller of an MQ-9A unmanned aircraft (tail number 12-4209) while the engine was running during ground testing at Gray Butte Airfield, California. The mishap resulted in fatal injuries to MTE1.
Sequence of Events
The mishap occurred during a ground test (MGT) conducted by the Air Force Life Cycle Management Center (AFLCMC) Detachment 3. The purpose of the test was to assess electromagnetic interference/compatibility (EMI/EMC) with a new software version loaded on the MQ-9A. The test consisted of two objectives; the first was completed before a midday break. After the break, the test team restarted the aircraft engine. At 7:51 p.m., the Mishap Test Director directed MTE1 to take telemetry readings from weapons on the aircraft for EMI/EMC evaluation. MTE1 proceeded to weapons station 6 on the right wing without checking in with the Crew Chief. After taking measurements with a handheld meter, she walked toward the rear of the aircraft to access weapons stations on the left wing. Without looking up to assess her position relative to the propeller, she walked directly into the rotating propeller, sustaining fatal injuries.
Causes
The Accident Investigation Board (AIB) President found, by a preponderance of the evidence, two causes of the mishap: 1. MTE1 was incorrectly instructed or trained on how to take telemetry readings from loaded weapons on the MQ-9A while the engine was running. 2. MTE1 lost situational awareness while taking telemetry readings.
Additionally, two factors substantially contributed to the mishap: a clear lack of communication among the test team and ground support personnel, and a rushed testing environment due to previous delays and cancellations.
Background
The MQ-9A (tail number 12-4209) was operated by contractors from a Ground Control Station (serial number 08-5049). The aircraft and GCS were assigned to AFLCMC Detachment 3 at Gray Butte Airfield. The Mishap Test Director and Mishap Test Engineer were civilian contractors employed by Sumaria Systems LLC.
Investigation
The AIB conducted a thorough investigation, reviewing training records, procedures, and human factors. The report concluded that improper training and loss of situational awareness were the primary causes, with communication failures and time pressure as contributing factors.