What happened
During a landing operation, a heavily loaded fuel tanker encountered a 3-knot tailwind, causing the aircraft to overshoot the departure end of the runway. The runway, which consisted of gravel, was approximately 3,150 feet in length, with the final two-thirds of the surface covered in ice. After overrunning the runway, the aircraft came to a stop on a frozen river.
Findings
Investigations into the incident focused on the braking and deceleration capabilities of the aircraft. The crew reported that the propellers either failed to engage reverse pitch or were slow to respond during the landing roll. However, a physical examination of the aircraft confirmed that all propeller blades were in the reversed position at the time of the accident.
Several contributing factors were identified regarding the landing calculations and environmental conditions:
- The ambient temperature was extremely low, ranging between -30 and -35° F.
- The performance charts utilized by the crew to determine required landing distances were intended for use on concrete runways rather than ice-covered gravel.
- The calculations for stopping distance did not account for the use of reverse propeller thrust.
- Post-accident analysis using the same performance charts indicated that the required landing distance for the specific weight of the flight was approximately 100 to 200 feet longer than the available runway length.