What happened
On 22 August 2023, an unmanned MQ-9A (T/N 14-4267) operating from Kanoya Air Base, Japan, was destroyed following a sequence of automated flight logic transitions and pilot error. The aircraft, operated by a Launch and Recovery Element from the 319th Expeditionary Reconnaissance Squadron, touched down normally on Runway 08 at 02:02:11Z. Following touchdown, the pilot moved the throttle to ground idle to begin deceleration.
Three seconds later, the ground control station lost the uplink to the aircraft. This loss of signal triggered the High Speed Lost Link Logic (HSLLL), an automated system that immediately applied full engine power to initiate a go-around maneuver. Because the pilot's manual throttle setting remained at ground idle, the aircraft accelerated via automated power settings and lifted off the runway.
Six seconds after liftoff, the uplink was restored. Upon reconnection, control reverted from the automated logic back to the pilot's manual inputs, which were still set to ground idle. This sudden drop in power caused the airspeed to decay, leading to an aerodynamic stall. In an attempt to recover, the pilot commanded full throttle and a steep pitch-up attitude, which further exacerbated the stall. The aircraft impacted the runway 17 seconds after liftoff, causing the landing gear to collapse, propeller blades to bend, and the left wingtip to be severed upon striking a light box. There were no fatalities or injuries, but the loss of the aircraft was valued at $21,500,000.
The investigation
The investigation examined the technical state of the datalink systems and the crew's response to the emergency. Investigators identified that a damaged connector on the Upper Directional Antenna Cable had degraded performance, forcing the crew to use a suboptimal antenna configuration. Additionally, discrepancies in the ground data terminal alignment and degraded fiber optic connections contributed to the signal instability.
Findings
- The primary causes of the mishap were the loss of uplink during the landing phase and the failure of the crew to execute proper go-around procedures or verify throttle and pitch settings during the lost link period.
- The crew failed to execute the required go-around procedure or disconnect the ground data terminal when the automated logic took over.
- The crew overlooked critical warning indicators, including an audible alarm, a red "LOS uplink-LOST" display, and the transition of the camera feed from daylight to infrared.
- The pilot's attempt to recover from the stall involved an excessive pitch-up command that worsened the aerodynamic condition.