Narrative:A Beechcraft MC-12W Liberty reconnaissance plane crashed northeast of Kandahar Airport (KDH) in Afghanistan, killing all four crew members.
The airplane was based at Kandahar and operated by the US Air Force on a combat intelligence, surveillance, and reconnaissance (ISR) mission.
The airplane, callsign Independence 08, departed Kandahar at 11:57 and entered orbit at 12:29. Upon entering the operating area about 12:29, they encountered a cloud deck partially covering their orbit area and a large, rapidly building towering cumulous cloud in the center of their orbit area from 17,000 ft to 24,000 ft mean sea level (MSL).
The towering cumulus clouds began to grow and drift into the airplane's orbit, prompting a request to climb from 20,000 ft to 23,000 ft. This translates to climbing from 13,800 to 16,800 ft above ground level.
The airplane was in a left hand orbit, preparing to shift the orbit, when the pilot initiated the climb with the autopilot on at 12:40:40.
While or just after initiating the climb, the pilot continued working an orbit adjustment to better service tracking an active target, and approximately ten seconds after the climb was initiated, the climb rate increased. Fifteen seconds afterward the pilot noticed he had allowed the airspeed to decrease during the climb, stating, "A little slow, correcting." Seven seconds later, the mission commander in the right hand seat said, "Alright, firewall," meaning to advance the throttles as far forward as they would go, and one second later, the auto-pilot was disengaged.
The propellers on the MC-12W do not counter-rotate, and advancing the power in the MC-12W produces left-handed torque and P-factor, creating a left yaw and making the aircraft to want to turn left; the airplane was already in a left-hand turn and left bank. Two seconds after calling to "firewall" the throttles, and one second after auto-pilot disengagement, the bank angle warning tone sounded, indicating the left bank had rapidly increased to greater than 50 degrees. The mission commander again called for full power, and four seconds later, he directed "eyes inside," telling the pilot to refer to his instruments for attitude and airspeed information; contemporaneously, the stall warning sounded. The stall warning horn stopped after five seconds, and a second later, background noise indicates items began flying around within the cockpit and the bank angle warning stopped. The pilot stated: "Whoa, pull up".
The mission commander then advised the pilot to look at his airspeed and took over the aircraft, calling for a reduction in power. Four seconds after the mission commander took the aircraft, the aircraft overspeed warning sounded, followed by the landing gear horn sounding. The landing gear horn indicates the throttles were reduced toward idle, and it did not sound until 15 seconds after initial stall warning sounded. The MA reached a maximum recorded height of 20,900 ft. and lost approximately 15,000 ft before impacting the ground.
The airplane impacted with the fuselage slightly nose-low, in a left bank, with minimal forward momentum. The airplane was destroyed upon impact and burned during the post-crash fire .
"I find by clear and convincing evidence the cause of the mishap was a stall due to insufficient airspeed, while in a climbing left turn, which developed into a left spin followed quickly by a high-speed spiral, from which the crew was unable to recover. Additionally, I find, by a preponderance of evidence, each of the following three factors substantially contributed to the mishap: (1) orbit weather that impeded visibility and masked the horizon; (2) pilot inexperience in the MC-12W; and (3) known MC-12W program risks associated with sustaining required combat capability in theater."
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