Cleveland, TN, USA
N112EC
Hiller UH-12E
According to the pilot, the externally slung, hydraulically operated fertilizer bucket stopped dispensing. With no ground handling crewman available, the pilot set the rotorcraft down to troubleshoot the problem. With engine rpm near maximum to run the hydraulic pump to its maximum output, the pilot climbed out of the left seat, onto the left skid to read the externally mounted hydraulic pressure gage. While egressing the cockpit, the pilot accidentally bumped the collective control to the "increase rotor pitch" position, and the rotorcraft became airborne without him aboard. The rotorcraft climbed to about 500 feet agl, in circling flight until the loaded fertilizer bucket began swinging in ever-divergent oscillations causing rotorcraft instability and eventual main rotor-to-boom strike and crash.
On January 5, 2001, about 1500 central standard time, a Hiller UH-12E, N112EC, registered to B and S Air, Inc., operating as a Title 14 CFR Part 137 aerial application flight, crashed in the vicinity of Cleveland, Tennessee. Visual meteorological conditions prevailed and no flight plan was filed. The rotorcraft was destroyed, and the commercially-rated pilot, was not injured. The flight originated about 15 minutes before the accident. According to the pilot, he was applying fertilizer to pine trees from a hydraulically operated Simplex bucket on a 25-foot external sling when the bucket stopped dispensing. He landed the rotorcraft to try and determine if the malfunction was hydraulic or mechanical. To do so, since he was the sole occupant aboard, and the ground handler was running an errand, he had to set the craft down, keep operating power on the engine, step out of the cockpit onto the skid, and read the externally mounted hydraulic pressure gage. As he exited the cockpit, he slipped and somehow during the fall, he bumped or grabbed the collective. As the unmanned rotorcraft lifted off, the left landing skid struck him in the face, and by the time he could react, the rotorcraft was at 100 feet agl, and climbing. The craft stayed airborne for about 30 to 45 seconds while attaining an altitude of about 500 feet agl, in a right spin before the main rotor collided with and severed the tail boom. According to an FAA inspector, the engine power had to be near 100 percent operating rpm to effectively check hydraulic pump output. As the left-seated pilot swung his right leg over the cyclic, he tripped and fell. While falling, his left hand, which was positioned aft of the collective's pivot point, somehow engaged the collective control column to the full up position. Once the rotorcraft was airborne and climbing in right circling flight, the loaded fertilizer bucket began ever-diverging oscillatory motions until it caused the main rotor to severe the tail boom and the rotorcraft crashed about 1,500 feet from its liftoff point.
The PIC's failure to follow safe operating procedures for the maintenance of the rotorcraft's external aerial application equipment, resulting in inadvertent activation of collective as he egressed the rotorcraft, causing unmanned flight, in-flight break-up, and collision with terrain.
Source: NTSB Aviation Accident Database
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