NTSB Factual Report

On June 6, 2005, at 1800 eastern daylight time, a 1966 Hughes TH-55 helicopter, N2KX, was destroyed during an attempted takeoff from the Paintsville-Prestonsburg-Combs Field Airport (3I6), Paintsville, Kentucky. The certificated private pilot/owner received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91.

In a telephone interview, the pilot/owner explained that the purpose of the flight was to perform a cyclic-rigging check, and a rotor-rpm check during autorotation.

The pilot/owner loaned the helicopter to a friend for about 20 hours of flight instruction. The friend returned the helicopter, and said that it "didn't feel right," but was unable to identify the reason for his discomfort. The two then flew the helicopter, and the owner said the cyclic felt "out of rig" because it was aft of its nominal position during cruise flight. During autorotation, the main rotor reached its rpm limit, and nearly over sped.

The pilot and his friend subsequently met on the day of the accident to troubleshoot the helicopter. They each performed a preflight inspection, and neither noted any mechanical deficiencies.

The pilot started the helicopter, and performed the run-up checks, to include the magneto check and the rotor-engagement check. These checks were performed at operating rpm, with the helicopter "light on the skids."

The pilot then completed the before takeoff checks, and initiated a takeoff to a hover. According to the pilot, "I pulled it up to a hover, and I'm not sure what happened after that. I mean, I pulled up on the collective, and it went all to pieces."

As the pilot applied collective pitch and power for takeoff, he felt a few bumps. He was aware of the phenomena of ground resonance, and continued applying collective pitch and power, but the helicopter would not take off. Within seconds, he had no control of the helicopter, as it disintegrated around him. He also recalled sensing that the main rotor struck the tailboom, but couldn't recall when in the sequence that it took place.

The pilot's friend stood about 100 feet away and witnessed the accident. His version of the events leading up to the accident was consistent with the pilot/owner's. He described the engine start and the run-up checks, and said that he anticipated the takeoff.

According to the witness, "It happened so fast! It started to shake, a blade hit the tailboom, and it shook to pieces." He added that the helicopter never left the ground, and that it rocked side-to-side two or three times before it came apart.

The helicopter had accrued 4,848 total flight hours. Its most recent annual inspection was completed April 24, 2005, at 4,822 aircraft hours.

The pilot held a commercial pilot certificate with ratings for airplane single engine land, and instrument airplane, and a private pilot certificate with a rating for rotorcraft-helicopter. He also held a flight instructor certificate with a rating for airplane single engine, and mechanic certificate with a rating for airframe.

The pilot was issued a Federal Aviation Administration (FAA) second-class medical certificate on December 9, 2003. He reported 2,200 total hours of flight experience on that date. The pilot estimated that he had 170 total hours of experience in helicopters, 150 hours of which were in make and model.

At 1753, the weather reported at Julian Carroll Airport (JKL), Jackson, Kentucky, about 27 miles west, included clear skies, calm winds, and 10 statute miles of visibility.

NTSB Probable Cause

the pilot's inadvertent encounter with ground resonance which resulted in destruction of the helicopter.