Bell 206L-3 Hard Landing During Practice Autorotation

Casualties unknown • Grand Central Aerodrome – Helicopter General Flying Area, ZA

A private Bell 206L-3 helicopter sustained substantial damage during a practice autorotation at Grand Central Aerodrome after the pilot failed to maintain rotor RPM.

What happened

On 1 September 2007, a Bell 206L-3 helicopter, registration ZS-RUM, was involved in an accident while performing training maneuvers near Grand Central Aerodrome. The pilot, who also owned the aircraft, was practicing autorotations in the helicopter general flying area. The weather was clear with light winds.

During the third attempted autorotation, the pilot initiated a flare at an altitude of approximately 50 feet above ground level. At this stage, the aircraft was traveling at an airspeed between 70 and 80 knots. The pilot attempted to increase throttle to recover the declining main rotor RPM, but was unable to stabilize the engine power and rotor speed in time. Consequently, the aircraft executed a hard landing on a slightly downhill slope.

Upon impact, the main rotor blades struck the aircraft's vertical stabilizers and the tail-rotor driveshaft assembly. The force of the impact caused a section of the driveshaft to detach and land roughly 20 meters away from the primary wreckage. The pilot, who was the sole occupant, escaped the incident without injury.

The investigation

SACAA AIID investigators examined the aircraft's maintenance history and the circumstances of the flight. The investigation confirmed that the Bell 206L-3 had been maintained according to the approved schedule, with the most recent mandatory periodic inspection completed only four and a half hours prior to the accident. The maintenance organization held valid approval at the time of service.

Technical analysis of the flight revealed that the aircraft was in a serviceable condition with no recorded mechanical defects that could have contributed to the event. The investigation also noted that the pilot was experienced on the type and was performing a familiar maneuver intended to sharpen flying skills.

Probable cause

The pilot allowed the main rotor RPM to drop below the minimum safe operating range during a practice autorotation while at a low altitude, leading to a hard landing and subsequent contact between the rotor blades and the airframe.

Frequently asked questions

What happened in the 2007-09-01 Bell 206L-3 accident near Grand Central Aerodrome – Helicopter General Flying Area, ZA?

A private Bell 206L-3 helicopter sustained substantial damage during a practice autorotation at Grand Central Aerodrome after the pilot failed to maintain rotor RPM.

What aircraft was involved and where did it happen?

The accident on 2007-09-01 involved a Bell 206L-3, registration ZS-RUM, at Grand Central Aerodrome – Helicopter General Flying Area, ZA.

What was the probable cause of the accident?

The pilot allowed the main rotor RPM to drop below the minimum safe operating range during a practice autorotation while at a low altitude, leading to a hard landing and subsequent contact between the rotor blades and the airframe.

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