What happened
On 7 May 2002, an MBB BO-105, registration ZS-RAW, was engaged in a South African Police Service (SAPS) rescue mission over the Johannesburg Central Business District. The crew had responded to reports of a building fire and were circling the structure to monitor for trapped individuals. Upon observing approximately six people on the roof, the pilot and crewmember coordinated a plan to facilitate a rescue.
As the aircraft approached the building from a southerly direction, the crewmember opened the left-hand sliding door. Despite increasing smoke density, the pilot continued the approach toward the building's ledge. While the aircraft was hovering near the rooftop, the crewmember assisted the first person onto the helicopter. During this maneuver, the aircraft encountered turbulence, causing the main rotor blades to strike a staircase located on the roof.
The investigation
The investigation examined the flight path, the environmental conditions, and the mechanical response of the aircraft following the impact. Investigators reviewed the pilot's account of the mission, noting that the crew was actively monitoring obstructions, such as a washing line and the staircase, prior to the incident. The investigation also looked into the impact of the turbulence encountered during the boarding process.
Findings
- The aircraft was performing a specialized rescue operation for the SAPS.
- The crew was aware of the proximity of the rooftop staircase and other obstructions.
- Turbulence caused the aircraft to drift laterally during the hover.
- The main rotor blades made contact with the staircase during this period of instability.
- Following the strike, the aircraft experienced significant vibrations, prompting the pilot to abort the mission.
- The pilot successfully executed a semi-autorotative landing on a nearby rooftop, maintaining control of the MBB BO-105 despite the increased vibration levels.
- There were no injuries to the crew or the person being rescued, and no third-party property damage was reported.