Introduction
On 23 February 2006, a Bell 206L-3 helicopter, registration ZS-HSX, was involved in an accident during a chartered sightseeing flight. The helicopter was operated by an airline transport pilot with 1660.9 total flying hours, including 1417.8 hours on the Bell 206 type. The flight departed from and was scheduled to return to the Victoria and Alfred Waterfront in Cape Town, South Africa.
Flight Sequence
The helicopter carried one pilot and six passengers. The takeoff was uneventful, though the pilot noted to the passengers that the helicopter felt "a bit heavy." The helicopter climbed normally to an altitude of 2500 feet above ground level (AGL) and maintained that height. While flying over the Scarborough area, the pilot heard an "engine out" audio warning, followed by a low rotor rpm warning. The pilot immediately informed the passengers and began searching for a suitable landing area. He lowered the collective pitch lever and initiated an autorotation toward an open sandy beach.
Accident
A passenger seated in the front, who was also a private pilot, described the autorotation as normal and under control, with no apparent panic from the pilot. The helicopter was flown at 60 knots indicated airspeed (KIAS). However, shortly before touchdown, the helicopter contacted the ground hard. The skid toes struck first and dug into the soft sand, causing the helicopter to skid forward uncontrollably. It came to rest on its starboard side a few meters from the initial impact point. All seven occupants egressed from the helicopter.
Damage and Injuries
The helicopter sustained extensive damage. The skids failed during the impact sequence. The main rotor blades severed the tailboom, and the tailboom and tail rotor assembly failed upon ground contact. The under-fuselage and cabin structure areas were also damaged. All seven occupants sustained serious injuries and were transported to a hospital for medical treatment. There were no fatalities.
Investigation Findings
The last mandatory periodic inspection (MPI) was certified on 23 December 2005 at 6771.2 airframe hours. The helicopter had accumulated an additional 99.5 hours since that inspection. The investigation determined that the engine experienced substantial power degradation due to a failure of the P3 air pipe connecting the governor unit and the fuel control unit (FCU).
Probable Cause
The probable cause of the accident was a hard landing during an emergency autorotative landing. Contributory factors included substantial engine power degradation due to the failure of the P3 air pipe adjoining the governor unit and the FCU, and the pilot's failure to cushion the touchdown impact forces accordingly, which resulted in a hard landing.