Accident Overview
On 26 May 2002 at approximately 1040Z, a Piper PA32-300 aircraft registered ZS-JGH was on a private flight from Bloemfontein Aerodrome to Lanseria Aerodrome. The pilot, aged 45 with 68.7 total flying hours (45.4 hours on type), was accompanied by two passengers. While descending to 7500 feet AMSL to fly below the Johannesburg Terminal Control Area, the engine did not respond to throttle inputs, maintaining a manifold pressure of 13 inches of mercury. This power setting was insufficient to sustain level flight, necessitating a forced landing in an open field. During the landing, the undercarriage sustained damage. None of the three occupants were injured, and none were killed.
Meteorological and Site Information
The accident site was located near Shaft 4 of the Westdene Mine, at GPS coordinates S26°21.82' E027°41.51'. Meteorological conditions at the time included light and variable surface wind, temperature 17°C, and visibility CAVOK.
Investigation Findings
On-site investigation revealed that the throttle cable rod end fitting had separated from the throttle arm. The rod end bearing had seized onto the ball end, and the bearing came loose in the rod end fitting. The larger washer was not fitted to the assembly, allowing the rod end to slip over the bolt head.
The last Mandatory Periodic Inspection (MPI) prior to the accident was certified on 27 July 2001 at 2701 airframe hours, with an additional 48 hours flown since then. As far as could be determined, all applicable Airworthiness Directives and Service Bulletins/Letters had been complied with. The Aircraft Maintenance Organisation held a valid approval expiring on 4 March 2002.
Probable Cause
The probable cause was the separation of the throttle cable rod end from the throttle arm, causing the engine to be unresponsive to pilot power demands. The throttle arm positioned the engine to deliver only reduced power, inadequate for level flight. A contributing factor was the seized/worn throttle cable rod end fitting, which was not detected or rectified during the last MPI.