Low Rotor RPM Incident Involving Robinson R22 Beta at Grootvlei

Casualties unknown • On the South-Westerly runway in a farm aerodrome in the Hoopstad district, ZA

A private helicopter flight experienced a sudden loss of rotor RPM during its final approach, resulting in a hard landing near Grootvlei.

What happened

On 31 July 2005, a Robinson R22 Beta, registration ZS-HXS, was conducting a private visual flight rules (VFR) mission from Rand Aerodrome toward a private landing site in the Grootvlei area. The flight was carrying one pilot and one passenger under favorable meteorological conditions, characterized by clear visibility and light winds.

As the aircraft descended to approximately 10 feet above the ground while circling a farm, the pilot's door unexpectedly swung open. The pilot attempted to manage the situation by requesting the passenger to secure the door. Shortly after this distraction, a low rotor RPM audio warning was triggered. Despite the pilot's immediate efforts to recover the engine speed by adjusting the throttle and lowering the collective, the aircraft lost altitude rapidly, leading to a hard landing.

The investigation

SACCA AIID investigators examined the circumstances surrounding the loss of rotor RPM and the subsequent impact. The investigation confirmed that the aircraft was airworthy, with a valid certificate of registration and airworthiness at the time of the event. Maintenance records indicated that the aircraft had completed 34 hours of flight time since its last maintenance inspection. Furthermore, all required airworthiness directives and service bulletins had been addressed, and the maintenance organization responsible for the aircraft had a satisfactory audit history.

Findings

  • The primary cause of the incident was the decay of rotor RPM during the landing approach.
  • A significant contributing factor was the diversion of the pilot's attention and increased tension following the sudden opening of the cockpit door.
  • There were 0 fatalities and 0 injuries resulting from the impact, though the aircraft suffered significant structural damage to the lower fuselage, skids, and cross tubes.

Probable cause

The pilot allowed the rotor RPM to decay during the approach to landing, a situation exacerbated by a loss of focus when the cabin door opened.

Frequently asked questions

What happened in the 2005-07-31 Robinson R22 Beta accident near On the South-Westerly runway in a farm aerodrome in the Hoopstad district, ZA?

A private helicopter flight experienced a sudden loss of rotor RPM during its final approach, resulting in a hard landing near Grootvlei.

What aircraft was involved and where did it happen?

The accident on 2005-07-31 involved a Robinson R22 Beta, registration ZS-HXS, at On the South-Westerly runway in a farm aerodrome in the Hoopstad district, ZA.

What was the probable cause of the accident?

The pilot allowed the rotor RPM to decay during the approach to landing, a situation exacerbated by a loss of focus when the cabin door opened.

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