What happened
On 11 October 2003, a Sikorsky S76C Spirit, registration G-JCBJ, was involved in a heavy landing at Cranfield Airfield during a training flight. The flight was being conducted as a proficiency check for the handling pilot, involving various instrument and engine-inoperative procedures.
During the session, the crew attempted a practice rejected takeoff following a simulated engine failure, utilizing a short-field takeoff profile. As the aircraft reached approximately 130 feet, the examiner used a training switch to simulate the failure of the right engine. In accordance with the procedure, the handling pilot lowered the nose and adjusted the collective to manage rotor RPM. However, the aircraft entered a rapid descent. Both crew members noted an abnormally high rate of descent and observed that the aircraft failed to achieve translational lift. Despite applying full collective in an attempt to cushion the impact, the helicopter struck the ground heavily on its left main landing gear, followed by the right main gear and nose gear. The impact resulted in structural damage to the tail cone.
The investigation
Because the aircraft was not equipped with a Flight Data Recorder, investigators relied on data retrieved from the Cockpit Voice Recorder (CVR) and witness accounts. Spectral analysis of the CVR recordings allowed investigators to monitor rotor RPM (Nr) fluctuations. The investigation also included an examination of the engines at a manufacturer facility in the USA, which found no defects or malfunctions.
Investigators also reviewed the meteorological conditions, noting that while surface winds were light, the aircraft's position near airfield hangars could have influenced local wind direction. The investigation examined the specific mechanics of the OEI (One Engine Inoperative) training switch and the procedures outlined in the Rotorcraft Flight Manual (RFM) for short-field rejected takeoffs.