Robinson Helicopter R44 N7094J accident near Charlotte, North Carolina

Probable cause

The inadequate inspections of the forward left control rod end attachment hardware to the stationary swashplate by the pilot and by maintenance personnel, resulting in an eventual loosening and backing out of the hardware and subsequent loss of helicopter control.

NTSB analysis

The purpose of the flight was to provide video training for a local staff meteorologist over a simulated news scene. About 5 minutes into the flight, the pilot began a series of left, 360° orbits over an interstate highway. During the third orbit, helicopter control was lost and the helicopter entered a steep descent until it impacted a grassy area adjacent to the highway. The pilot made a radio call before impact stating that they were “going down.” The helicopter impacted a grassy area adjacent to an interstate highway. There was no postaccident fire.

An examination of the helicopter’s flight controls after the accident revealed the forward left control rod end that should have been connected to the stationary swashplate on the main rotor was disconnected and the connecting hardware was missing. A metallurgical examination of the remaining components suggested that the connecting hardware, including a threaded bolt, nut, palnut, two washers, and two hat-shaped spacers were loose and backed out during the flight. It is unlikely that the hardware was secure before the flight and may have been loose for multiple flights before the accident.

Additional examination of the remaining hardware revealed that one of the two spacers was installed backwards, most likely during the field overhaul of the helicopter about three years before the accident. The subject hardware was required to be inspected for security by the pilot during each preflight inspection and by maintenance personnel at each 100-hour/annual inspection.

The pilot tested positive for quinine and the pain reliever tramadol and was under a physician’s care for arthritis and polyarthralgia that was unreported to the Federal Aviation Administration. However, based on the mechanical issues and the actions of the pilot immediately before the accident, performance impairments were not an issue. Thus, it is unlikely that the effects from the pilot’s use of quinine and tramadol were factors in this accident.

Text from the NTSB. Open the NTSB docket for ERA23FA070 for the full record.