What happened
On May 12, 2021, an Aerospatiale AS350 B2 (registration N841BP) was involved in an accident near Yukon, Oklahoma. The flight was being conducted as a public aircraft instructional flight for the US Customs and Border Protection. The flight crew had departed Will Rogers International Airport (KOKC) and proceeded to Clarence Page Municipal Airport (KRCE) to perform training maneuvers, including approaches and simulated emergencies.
During the simulated emergency procedures, the crew practiced turning the hydraulic system off and on using an unguarded, push-button cut-off switch located on the end of the pilot's collective stick. Following these procedures, the crew performed a series of "quick stops."
As the pilot completed a final quick stop and entered a climbing left turn, the helicopter began to yaw left. The pilot reported that as he adjusted his grip on the collective, he felt the hydraulic cut-off button with his thumb. This action caused the hydraulics to go offline, resulting in a hard left spin. The flight instructor noted that the aircraft began yawing approximately 25 feet above ground level and that control loads became excessive immediately after the hydraulic warning light illuminated.
Despite the instructor's instructions to reactivate the hydraulics, the pilot attempted to press the button three times without success. The instructor attempted to take control of the aircraft, but the pilot did not relinquish control. The helicopter continued to spin, impacted the ground in a nose-down attitude, and rolled onto its right side. Both occupants were not injured, but a postimpact fire consumed much of the aircraft.
Findings
An examination of the airframe and engine revealed no preimpact abnormalities, though the investigation of the wreckage was limited by the intensity of the postimpact fire. The US Customs and Border Protection Air and Marine Operations Division noted that their selection process had failed to identify that the pilot receiving instruction was not properly qualified for the program.