Incident Overview
On 10 June 2002 at 0930Z, a Beech 65-A90 aircraft, registration ZS-IRJ, was operating a domestic charter flight from Karens Camp (private aerodrome in the Waterberg region) to a private aerodrome near Messina. The aircraft, with one pilot and five passengers on board, departed under fine weather conditions with no cloud cover and calm winds.
Sequence of Events
After take-off from Karens Camp, which has a grass runway, the pilot experienced difficulty retracting the undercarriage and could not obtain a positive indication that the gear had retracted. He subsequently extended the undercarriage again and diverted to Wonderboom aerodrome with the gear in the extended position.
Upon arrival at Wonderboom, the aircraft's undercarriage was inspected from the ground. It was observed that the right-hand main gear torque link had failed. The pilot then executed a successful precautionary landing on Runway 11. Despite the torque-link failure, the right-hand main gear continued tracking straight. No injuries were sustained and no further damage was caused to the aircraft.
Probable Cause
The investigation determined that although parts of the fracture surface sustained severe damage subsequent to the failure of the torque-link, the available evidence suggests that failure occurred as a result of an overload shear fracture, which could have resulted from operating from the uneven/bumpy runway surface. The presence of a pre-existing crack could not be ruled out entirely, as the fracture surface containing the threaded hole for the grease nipple, which would have acted as a stress riser, was severely damaged and could not be analyzed.