What happened
On February 20, 2007, an MBB-BK-117 helicopter, registration ZS-HSD, was conducting aerial work when it experienced a hard landing at the Gauteng Police Provincial Office in the Johannesburg CBD. The flight originated from the Johan Coetze Heliport (Police College).
As the pilot attempted to land at the unlit landing zone, the aircraft approached from the west. While maintaining a high hover at approximately 15 feet, the pilot lost visual contact with the ground. During this period, the aircraft began a steady descent while simultaneously drifting backward and to the left. This movement resulted in the aircraft making forceful contact with the ground.
The investigation
The investigation examined the aircraft's maintenance history and the environmental conditions at the time of the incident. The pilot was found to be commercially licensed, medically fit, and fully qualified for the operation. The aircraft had accumulated 3,086.9 total airframe hours, with the most recent maintenance inspection completed approximately four months prior.
Regarding the damage, the impact affected the rubber boots and the cross tube on both sides of the aircraft. Subsequent repairs by the Approved Maintenance Organization (AMO) focused on the undercarriage, where the rear tubes were replaced; the investigation noted that the skids and cross tubes themselves were found to be undamaged during the repair process.
Findings
- The primary cause of the hard landing was that pilot vision was obstructed by a dust inversion created by the main rotor blades during the hover.
- The landing zone was unlit at the time of the approach.
- Environmental conditions were characterized by high dust levels, which contributed to the loss of visual references during the final descent.