What happened
On April 2, 2023, an Airbus Helicopters EC130 T2 helicopter, registration N231SH, was operating as a Part 135 air ambulance flight when it crashed near Chelsea, Alabama. The accident resulted in 2 fatal injuries to the pilot and flight nurse, and 1 serious injury to the flight paramedic.
Witnesses observed the helicopter hovering parallel to a road, approximately 3 to 4 feet above the ground. The aircraft then rapidly ascended and turned toward the road, passing over a vehicle. After several seconds, the helicopter turned 180 degrees back toward a field, at which point it pitched nose-down and impacted the roadway. Dash camera footage from a local deputy sheriff captured the aircraft emerging from behind trees in a steep, nose-down attitude before striking the road and sliding approximately 20 feet into the grass.
The investigation
Examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have prevented normal operation. While the engine showed evidence of a free turbine overspeed, the investigation found no preimpact mechanical failures. The helicopter's crash-resistant fuel system remained intact, and the fuel tank was not breached.
An onboard cockpit image recorder was recovered and analyzed. The video showed that the flight was uneventful until the pilot began a hover over a gravel road. During the hover, the aircraft moved forward as altitude increased from 50 feet to 110 feet agl. The attitude indicator showed the aircraft reached a maximum of over 20 degrees nose-up pitch and 20 degrees right roll. During this period, there was no appreciable change in the pilot's pedal or cyclic position. The aircraft then transitioned from a nose-high attitude to an extreme nose-low attitude while continuing to roll right to a maximum of 30 degrees. The pilot's subsequent left and aft cyclic inputs were insufficient to recover the aircraft.
Toxicology testing of the pilot's blood and liver tissue revealed the presence of cetirizine, cyclobenzaprine, and diphenhydramine. These substances are all potential central nervous system (CNS) depressants.
Findings
- The pilot's delayed corrective inputs during maneuvering led to a loss of control.
- The pilot's use of multiple sedating medications likely contributed to a performance deficiency and delayed the application of appropriate control inputs.