What happened
On 23 April 2020, a C-1COJ-30, tail number 11-5736, assigned to the 37th Airlift Squadron, 86th Airlift Wing, was conducting a routine periodic evaluation flight at Ramstein Air Base, Germany. The mission involved a single-ship takeoff and a maximum effort (assault) landing using a specific painted landing zone as part of a pilot's evaluation process.
During the maximum effort landing, the aircraft experienced a severe hard landing. The vertical acceleration reached 3.62g, significantly exceeding the aircraft's structural limit of 2.0g. Additionally, the sink rate was recorded at 834 feet per minute, surpassing the allowable limit of 540 FPM. Following the impact, the crew immediately initiated a go-around and coordinated with Air Traffic Control for a visual approach to complete a full-stop landing. There were no fatalities or injuries reported.
The impact caused extensive damage to the aircraft, including the center wing, both outer wings, the engine mounting structures, and both main landing gear assemblies. The total estimated damage is approximately $20,917,089.
The investigation
The Air Force Accident Investigation Board examined the flight parameters, maintenance records, and environmental conditions. Investigators analyzed the aircraft's performance data, including sink rate and g-load, and reviewed the crew's actions during the approach.
The board also looked into maintenance software, specifically the DTADS system used for post-flight reporting. While it was noted that a failure to update the Desktop Debrief Workstation Computer (DDWC) prevented the timely detection of landing exceedances, the board determined this was not a substantially contributing factor to the accident itself.
Weather analysis showed that winds were within operational limits, with no significant wind shifts or tailwind components strong enough to cause the mishap. The investigation focused primarily on the pilot's energy management and power settings during the final stages of the landing.
Findings
- The primary cause of the mishap was the pilot's premature reduction of engine power, which began at 70 feet AGL and reached flight idle by 45 feet AGL.
- Substantially contributing factors included the crew's failure to identify the excessive sink rate and their failure to execute a timely go-around or arrest the descent before touchdown.