Accident Overview
On July 15, 2010, at 1600 eastern daylight time, a Robinson R22 Beta, registration N74603, experienced a hard landing near West Melbourne, Florida, resulting in substantial damage. The helicopter was operated by Blue Hole Helicopters Inc. under 14 CFR Part 91 and was registered to Eric A Spitzer LLC. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight. The certificated private pilot and passenger were not injured.
Pilot Account
The pilot reported taking off from an area of flat pasture. Approximately 5 seconds after takeoff, at an altitude of 80 to 100 feet above ground level, the clutch caution light illuminated briefly and then extinguished. The light illuminated again, and the pilot felt the aircraft vibrate. As the pilot initiated a descent and lowered the collective, he heard a loud pop and grinding noise from the rear of the aircraft. Engine rpm increased while rotor rpm decreased, and the nose tucked forward with limited aft cyclic response. The pilot autorotated, and the helicopter impacted the ground in a nose-low attitude.
Witness Observation
A witness reported seeing a belt, approximately 4 to 5 feet in length, falling from the helicopter around the time of the incident.
Post-Accident Examination
An FAA inspector examined the helicopter and found substantial damage to the landing gear, main rotor blades, and tailcone, consistent with a hard landing. One of the V-belts was broken with a clean break; a section was recovered away from the main wreckage, and the remaining portion was entangled in the other V-belt system. The unbroken belt was separated from its sheave and damaged by the broken belt. The belts were described as "not new" and had taken on a gray color.
A representative from Robinson Helicopter Company conducted a more detailed examination of the drive system. One half of one V-belt (a single vee) was found resting on the clutch shaft forward of the upper sheave, with a large portion of backing material still attached, including the area that carried the other vee. The other vee of that belt was located inside the cabin, peeled away from the backing. This vee had a partial break, while the other vee was completely disconnected. When the vees were matched together, the disconnect and partial break were in different positions.
The clutch actuator was disconnected at the upper support bearing mount, with angular and jagged fracture surfaces consistent with an overload fracture. The actuator extension measured 1.7 inches (normal range 1.1–1.4 inches; maximum 1.85 inches).
Maintenance History
A logbook entry indicated that the drive belts were removed and replaced 22.9 flight hours before the accident. It was not clear whether the same belts were reinstalled or replaced with new or used belts. The R22 Maintenance Manual requires inspection of the sheaves prior to installation of drive belts and cautions about the consequences of using an unserviceable sheave. For the upper sheave to wear from a serviceable condition to its observed condition in 22.9 hours, the aircraft would have to have been operated in very extremely sandy conditions. However, none of the other components appeared to have been subjected to such an environment.