Accident Overview
On December 11, 2019, at about 1630 mountain standard time, an Enstrom F28F helicopter, registration N65RS, was substantially damaged in an accident near Riverton, Utah. The pilot sustained minor injuries. The helicopter was not registered and was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Statement
In an interview, the pilot stated that he did not hold a pilot's certificate and had not flown the helicopter 'in years.' He intended to relocate the aircraft on his property. During the approach to land, while about 6 feet above ground level, the tail rotor may have struck an object. The pilot initially increased collective to execute a go-around, but the main rotors struck a tree. He then lowered the collective to land, resulting in a hard impact that caused substantial damage to the fuselage, main rotor, and tail rotor assemblies.
Witness Account
A witness located across the street from the pilot's residence observed the helicopter attempting to land in an open field. The witness saw the helicopter get close to the ground, then climb to about 30 to 40 feet above ground and begin rotating about the main rotor. The helicopter then descended and struck a tree before falling to the ground.
Aircraft Examination
Examination of the wreckage revealed that the tail rotor gearbox housing was broken across the gear interface, consistent with a severe ground strike while the tail rotor was turning. The left tail rotor control cable was separated, and the right cable was intact; both cables had been unbolted from the tail rotor controls by the owner to simplify recovery. Both tail rotor blades remained attached to the hub but were damaged, with skins separated from spars. Bending on one blade was consistent with rotation during impact. The tail rotor control system from the cable attachments through the blades was intact and operated smoothly. The separated left cable exhibited marks consistent with being cut by a blunt object with high energy, such as a tail rotor blade. Marks on the tail rotor drive shaft appeared to match the cable, consistent with the cable contacting the rotating shaft. No other preaccident mechanical failures or malfunctions were found that would have precluded normal operation.
Maintenance History
The helicopter was manufactured in 1990. The last registration certificate on file with the FAA was for the prior owner, dated October 26, 1993; registration was canceled on September 6, 2012. The last airworthiness certificate was dated February 21, 1990. The helicopter had been stored outdoors and not maintained for about four years. The last recorded maintenance for the aircraft and engine was September 18, 2015. One entry described a 100-hour inspection that initially found the engine unairworthy but later signed off as airworthy. Another entry described an annual inspection that found the airframe unairworthy, with a list of discrepancies provided to the owner on June 2, 2015, but the owner did not provide a copy. The entry also noted that the customer declined a main rotor blade track and balance check, deemed unairworthy by technicians due to excessive downtime.