What happened
On February 19, 2009, a US Customs and Border Protection (CBP) General Atomics MQ-9 unmanned aircraft, registration CBP-108, experienced a hard landing and tailstrike during a Launch and Recovery training mission. The incident occurred at Libby Army Airfield in Sierra Vista, Arizona, while the crew was performing the seventh of eight planned touch-and-go landings.
During the descent from approximately 1,200 feet, the aircraft was being hand-flown with autoflight modes disabled. As the aircraft descended through 400 feet, the pilot reduced power to 27.4%. At approximately six feet above the ground, the aircraft's airspeed was 74 knots, and a 9-knot tailwind component was present.
The instructor pilot instructed the student pilot to flare more to arrest the descent rate and to add power to initiate a go-around. However, the aircraft experienced a peak acceleration of +3.76g, coinciding with a hard touchdown. The instructor attempted to assist with the controls, but the aircraft stalled and impacted the runway. Following a second increase in acceleration to 4.8g, the aircraft bounced and entered heavy pitch and roll oscillations. The instructor took control of the aircraft, successfully executed a go-around, and climbed back to pattern altitude. The crew then completed a full-stop landing on runway 26.
The investigation
Data logger files were reviewed by General Atomics Aeronautical Systems, Inc. to analyze the sequence of events. The investigation found that the aircraft's vertical fin, including the rudder and tailwheel, sustained damage. Additionally, the propeller blades were bent, the left main landing gear wheel hub showed crush damage, and two cracks were identified in the lower cowl.
There was no evidence of pre-existing mechanical anomalies or maintenance issues. The aircraft was operating under a FAA Certificate of Authorization at the time of the event.