A Lockheed C-130J Hercules transport aircraft operated a 5 sector mission conducting medical evacuation flights in Afghanistan. Onboard a crew of 11 and two mobile patients for the third sector of the day.
The accident aircraft after the fire was extinguished (© USAF)
After a successful flight, the aircraft approached the runway at the Shank Forward Operating Base. The runway is located at 6809 feet MSL (Mean Sea Level, the height above mean sea level). The weather conditions at the destination were;
Visibility 5000 meters with dust and haze
Temperature 29 ºC
Altimeter setting 30.04 in-hg
wind 240º/18 knots gusting 26
For the first approach, the configuration was briefed as a Maximum Effort Landing (100% Flaps landing at speeds lower than normal), giving a shorter landing distance. On that first approach to runway 34, the crew determined they were high and too fast so a go-around was executed. While the aircraft was on the downwind leg for the 2nd approach ATC reported the wind at 250º/23 knots, gusting 28 knots. A straight crosswind. Due to the crosswind, the crew decides to fly a 50% flap approach, providing better roll control during high crosswind landings however the higher speed requires longer landing distances.
Just after turning base leg, another aircraft receives the latest wind, 230º/19 knots gusting 28 knots. This resulted in a tailwind component of 10 knots. (FDR Data later revealed a tailwind component of ~17 knots at touchdown.) When turning final the aircraft overshot the extended centerline, this was corrected and at 1/2 miles from the runway the aircraft was established on final approach, All looked normal, except the speed which was ~20 knots too fast. Just prior to touchdown the copilot called "100 feet, you're fast". The touchdown was normal and occurred 1500 feet from the threshold at a speed of 148 knots (27 knots above the calculated touchdown speed) with 5500 feet of runway remaining.
The accident aircraft after the fire was extinguished (© USAF)
During the landing roll, an alert came on for an "ANTI-SKID FAIL", which was not noticed by the crew. During the landing roll the crew encountered some directional control issues after braking and full reverse was selected. This was corrected by the crew. The brakes felt abnormal and the deceleration was not enough to stop the aircraft on the runway. At a speed of ~49 knots, the aircraft left the runway. After ~440 feet the aircraft struck a ditch, causing the nose gear to collapse and the right main landing gear to be ripped from the aircraft. The right outboard engine struck the ground, causing fuel and oil lines to break, spraying their contents over hot engine parts. causing the right-wing to catch fire. ~544 feet past the runway the aircraft came to a stop. All occupants safely evacuated the aircraft.
The accident aircraft being dismantled (© USAF Sgt B. Yarbrough)
The accident was investigated by the USAF Aircraft Accident Investigation Board and on the 17th of September 2013, they published their report (available by clicking here).
Summarised, they concluded;
"The causes of the accident were poor Crew Resource Management (CRM) and mishap pilot one's (MP1) late power reduction causing a 27 KIAS fast touchdown at a high altitude airfield (6,809 ft MSL).
The following contributing factors were identified;
Channelized Attention
Risk Assessment
Delayed Necessary Action
Response Set
Procedural Error.
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