Incident Overview
On 8 March 2017, at 1729Z, a Beechcraft King Air 90 (registration ZS-MHM) experienced a landing gear collapse during landing at Rand Aerodrome (FAGM), resulting in a runway excursion. The aircraft sustained damage to the lower fuselage, landing gear doors, flaps, both propellers, and lower engine nacelles. The sole occupant, the pilot, was not injured.
Flight History
The pilot had repositioned the aircraft from Lanseria Aerodrome (FALA) to Rand Aerodrome after a flight from Sir Seretse Khama International Airport (FBSK) in Botswana. On approach to runway 11 at FAGM, the pilot noted a landing gear unsafe warning indicated by an illuminated landing gear switch light and an intermittent warning horn. A go-around was performed, and ATC was requested to observe the landing gear position during a low-level fly-past. ATC reported that the nose gear was only partially extended and the main landing gears were not visible. The pilot then proceeded to the general flying area to troubleshoot.
Landing Gear System and Manual Extension Attempt
The normal landing gear extension uses an electric motor to drive actuators; a green light indicates locked gear. During the incident, this system failed. The pilot followed the manual extension procedure from the pilot's operating handbook (POH) Section 3, which involved cycling the gear, then using the emergency engage handle and pumping the extension lever. After approximately 40 minutes airborne, three green lights were not obtained. A second fly-past at dusk made observation difficult; ATC reported the gear appeared down, but the pilot still lacked cockpit indication. The pilot chose to land on the longer runway 29, shutting down both engines and feathering propellers on short final.
Probable Cause and Contributing Factors
The probable cause stated in the report is that the landing gear could not be lowered into the down and locked position via the normal or emergency system, causing the gear to collapse after touchdown and a runway excursion to follow. Contributing factors included a collapsed commutator end bearing in the landing gear motor, which caused excessive current flow and deactivated a circuit breaker located underneath the floor structure—out of sight and reach of the pilot. Additionally, a missing screw on a securing plate near the manual extension hand crank mechanism allowed the plate to shift, partially jamming the crank. This may have been interpreted by the pilot as the required pressure indicating full extension, potentially preventing the gear from locking fully.
Conclusion
The incident occurred under night conditions (sunset was at 1533Z). The pilot held a valid commercial pilot license and medical certificate with adequate experience. The aircraft had a valid certificate of airworthiness. Weather conditions had no bearing on the incident. No safety recommendations were issued.