What happened
On 14 August 2004, a Gazelle Mk 1, registration G-PAGS, was departing from a private site near the Stansted Control Zone for a flight to Cornwall. The flight was being conducted under good visibility and light northerly winds. Shortly after takeoff, while climbing through approximately 700 feet during a right-hand turn, the pilot and two passengers heard a loud bang. Following this noise, the aircraft exhibited a fishtailing motion, and the flight controls became light and unresponsive.
Fearing a potential failure in the drive train or a transmission overtorque, the pilot initiated an autorotation. Due to the lack of altitude and time to perform a 180-degree turn, the pilot opted to land in a cornfield directly ahead. The aircraft was flying downwind at the time. The pilot performed a progressive flare at roughly 80 feet above the ground, attempting to level the aircraft at the height of the crop. However, the helicopter subsequently dropped several feet through the corn, resulting in a heavy landing. Despite damage to the landing skids, fuselage, and tail boom, there were no injuries to the crew or passengers, and no fire occurred.
The investigation
The investigation focused on identifying the source of the audible bang and the subsequent loss of control effectiveness. Investigators examined the engine, drive train, and transmission for signs of mechanical failure or overtorque. Additionally, the possibility of a bird strike was considered. The investigation also noted a report from another pilot regarding the pilot's door occasionally popping open during flight, which can produce a significant noise.
Findings
- The investigation found no evidence of mechanical failure or bird strike within the aircraft's systems.
- The source of the initial loud noise remained unidentified.
- The pilot's door may potentially pop open under specific flight conditions, creating a loud noise that could be mistaken for a mechanical issue.