Training Helicopter Crashes at Rand Aerodrome During Autorotation Exercise

Casualties unknown • Rand Aerodrome, ZA

A Robinson R22 Beta sustained substantial damage after a student pilot's incorrect recovery technique led to a loss of rotor RPM during a training flight.

What happened

On 16 February 2010, a Robinson R22 Beta, registration ZS-HAI, was conducting a visual flight rules (VFR) training flight at Rand Aerodrome. The flight, operated by a training organization, involved a flight instructor and a student pilot performing various engine-off emergency sequences, specifically focusing on autorotation.

During an autorotation exercise at approximately 500 feet above ground level, the main rotor RPM began to decay. As the aircraft entered a turn, the student pilot executed an abrupt left turn and, in an attempt to manage the situation, pulled up the collective pitch lever. This action caused the rotor RPM to decay even further. Although the instructor attempted to intervene by lowering the collective pitch to stabilize the rotor, there was insufficient altitude and time remaining to prevent the impact. The helicopter struck the ground on its left skid and rolled onto its right side.

The investigation

SACAA AIID investigators examined the wreckage and the flight profiles of both occupants. The investigation confirmed that the aircraft was properly maintained and held a valid Certificate of Airability. The investigation also noted that the aircraft was operating slightly above its maximum certificated takeoff mass, weighing approximately 93.63 lbs over the 1300 lbs limit.

Review of the training organization's documentation revealed that the school's manual of procedure did not align with the official SACAA syllabus regarding specific flight exercises. However, the investigation found no mechanical defects in the flight controls or the engine that contributed to the loss of rotor RPM.

Findings

  • The primary cause of the accident was the incorrect recovery technique initiated by the crew, which allowed the main rotor RPM to decay without sufficient time for recovery.
  • The student pilot's decision to pull the collective pitch lever upward during the low RPM state exacerbated the decay.
  • The aircraft was operating in excess of its maximum allowable takeoff weight.
  • The flight instructor sustained minor injuries, including a broken elbow and a concussion, while the student pilot remained uninjured.
  • The Robinson R22 Beta sustained substantial damage to the tail boom, skid gear, and main rotor blades.

Probable cause

The crew failed to maintain adequate main rotor RPM during an autorotation maneuver because the student pilot applied incorrect collective pitch input, leading to a decay that could not be recovered before ground impact.

Frequently asked questions

What happened in the 2010-02-16 Robinson R22 Beta accident near Rand Aerodrome, ZA?

A Robinson R22 Beta sustained substantial damage after a student pilot's incorrect recovery technique led to a loss of rotor RPM during a training flight.

What aircraft was involved and where did it happen?

The accident on 2010-02-16 involved a Robinson R22 Beta, registration ZS-HAI, at Rand Aerodrome, ZA.

What was the probable cause of the accident?

The crew failed to maintain adequate main rotor RPM during an autorotation maneuver because the student pilot applied incorrect collective pitch input, leading to a decay that could not be recovered before ground impact.

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