Aviation Accident Summaries

Aviation Accident Summary DEN07LA024

Melrose, NM, USA

Aircraft #1

N24CF

Bell UH-1H

Analysis

The helicopter was in cruise flight approximately 600 feet agl (above ground level) when it experienced "moderate to heavy" vibration. The pilot said he knew the tail rotor had failed because the anti-torque pedals would go to the floor with no effect. He also knew the tail rotor had failed when he attempted to make a run-on landing. As they got nearer to the ground, the check pilot "got on the controls" and would not relinquish them. The check pilot pulled back on the cyclic and slowed the helicopter, which immediately started "spinning violently to the right." The pilot-in-command "slammed the collective down" in an attempt to hit the ground hard and turn the helicopter over and stop it from spinning. He tried to roll off the throttle (which is the proper procedure for loss of tail rotor thrust in accordance with the Pilot Operating Handbook), but the check pilot was on the controls and he could not override him. The pilot-in-command turned off the main fuel control in an attempt to shut down the engine and stop the helicopter from spinning. The helicopter impacted terrain and rolled over on its side. Examination of the helicopter revealed both tail rotor blades were missing. The 90-degree gearbox was still attached and the tail rotor drive shaft showed no damage. Despite an extensive search, the tail rotor blades were not recovered. No other anomalies were found.

Factual Information

On November 13, 2006, approximately 1110 mountain standard time, a Bell UH-1H, N24CF, registered to and operated by World Jet, Inc., of Fort Lauderdale, Florida, and piloted by a airline transport certificated pilot, was substantially damaged when it impacted terrain and rolled over following an autorotation 12 miles north and 2 miles east of Melrose, New Mexico. Visual meteorological conditions prevailed at the time of the accident. The business flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91, and no flight plan had been filed. The pilot was seriously injured, but the second pilot was not injured (received minor injuries). The cross-country flight originated at Fort Lauderdale with an en route refueling stop in Longview, Texas, and was en route to Albuquerque, New Mexico. The helicopter departed Longview at an undetermined time. The following is based on the accident report submitted by the company's owner (the pilot was still in the hospital). The helicopter was in cruise flight approximately 600 feet agl (above ground level) when it experienced "moderate to heavy" vibration (it is believed that this is when "the first tail [rotor] blade came off"). Airspeed was reduced. A few minutes later, the "vibrations almost went away" (it is believed that this is when the "second tail [rotor] blade came off"). The pilot made an autorotation to a corn field. The helicopter impacted the ground and rolled over on its right side. The crew exited the helicopter through the main door and was taken to a nearby hospital for treatment. A farmer, who was planting wheat nearby, said he saw the helicopter "flying about 100 to 150 feet above the ground," and heard the "rotors popping real loud." He watched as the helicopter "veered north from its westerly heading," which he described as a "gliding left descending turn." He got off his tractor and ran to the crash site. "One [of the pilots] stated he had tail rotor trouble," the farmer wrote. An FAA inspector interviewed the pilot in his hospital room on November 18, and the following is based on that interview. Prior to departing Fort Lauderdale, the main and tail rotor blades were "tracked." He personally inspected and greased the tail rotor hub. They took off and flew to Longview, Texas, where they spent the night. They planned to fly to Albuquerque, then on to Baja, Mexico, to film the Baja car race. The pilot said he knew the tail rotor had failed when he felt a "big vibration," then it diminished and he felt no resistance in the anti-torque pedals. He said the pedals would go to the floor with no effect. He also knew the tail rotor had failed when he attempted to make a run-on landing. As they got nearer to the ground, the check pilot "got on the controls" and would not relinquish them. The check pilot pulled back on the cyclic and slowed the helicopter, which immediately started "spinning violently to the right." The pilot-in-command "slammed the collective down" in an attempt to hit the ground hard and turn the helicopter over and stop it from spinning. He tried to roll off the throttle (which, according to the FAA inspector, is the proper procedure for loss of tail rotor thrust in accordance with the Pilot Operating Handbook), but the check pilot was on the controls and he could not override him. The pilot-in-command turned off the main fuel control in an attempt to shut down the engine and stop the helicopter from spinning. FAA examination of the helicopter showed both tail rotor blades were missing. The 90-degree gearbox was still attached and the tail rotor drive showed no damaged. Despite an extensive search, the tail rotor blades were not recovered.

Probable Cause and Findings

the in-flight failure and separation of both tail rotor blades. Contributing factors in this accident were the check pilot interferring with the controls and his failure to relinquish control to the pilot-in-command.

 

Source: NTSB Aviation Accident Database

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