History of the Flight
On 7 November 2003, a Eurocopter EC 120B helicopter, registration EI-IZO, was operating in the Swansea area in support of the Wales Rally Great Britain 2003. The helicopter, powered by a single Turbomeca Arrius 2F engine, had departed Cardiff Heliport at 0735 hours and visited several designated landing sites during the day. The pilot, a 36-year-old private pilot with approximately 350 hours of flying experience, occupied the right seat. A safety pilot, who held a Commercial Pilot's Licence and was a qualified instructor on type, sat in the left seat and handled radio communications and navigation assistance. Dual controls were fitted. The flight carried four passengers.
In the early afternoon, the helicopter flew to Swansea Airport for refueling and a lunch stop. Approaching from the east, the pilot executed a descending right turn to a hover into wind on the south side of the airfield. After being cleared to cross active Runway 10, the pilot hover taxied in a north-easterly direction with a crosswind of 090° to 120° at 15 to 20 knots, then came to a stationary hover over the apron. The safety pilot contacted the tower to request clearance to park in their current position; the controller agreed and suggested they could turn into wind if desired. The safety pilot indicated a suitable parking area to the right, but before the pilot could initiate a right turn, the helicopter unexpectedly yawed approximately 20° to the left and pitched nose-down.
The helicopter accelerated forward a short distance, and the nose and right skid contacted the paved surface. Both pilots applied full aft cyclic control but could not prevent ground contact. The passenger behind the pilot reported seeing the ground through the canopy above the pilot's head, indicating a steep nose-down attitude. The main rotor blades struck the ground, and the helicopter slewed around and slid on its right side. The tower controller, who had a clear view, initially thought the helicopter was transitioning to forward flight but then realized control was lost. He activated the crash alarm and took cover as the helicopter rolled over and slid toward the base of the tower.
The helicopter came to rest on its right side against a small airport tractor. Fire services arrived and assisted all five occupants in evacuating through the left rear door. No injuries were reported.
Meteorological Information
At the time, the region was under an unstable airmass with an easterly flow. The Swansea Airport weather observation at 1309 hours recorded surface wind 110°/20 knots, CAVOK conditions, temperature 12°C, and dewpoint 6°C. At 1537 hours, 66 minutes after the accident, the wind was 090°/14 knots. ATC recordings captured two surface wind reports just before the accident: 100°/20 knots and 120°/15 knots, one minute and 30 seconds prior, respectively. Another helicopter pilot on the south side reported gusty winds varying in direction and strength up to 25 knots.
Impact and Ground Slide
Initial ground contact occurred on the paved apron approximately 60 metres south of the control tower. The helicopter came to rest about 15 metres from the tower. Light ground markings indicated that extremities of the helicopter or rotor system contacted the surface for most of the distance. Examination of wreckage and markings suggested the fuselage initially contacted the pavement with light force in a steep nose-down attitude, slightly banked to the right, with low descent rate and limited forward speed. The main rotor blades then struck the ground. The inclined rotor disc and blade reaction likely caused the helicopter to accelerate northward (parallel to its initial longitudinal axis) and rotate about the rotor axis, resulting in tail-first motion. Damage to the tail-boom showed that main rotor blade tips severed the fenestron. The helicopter rolled to the right, and backward motion stopped when the lower rear fuselage collided with a steel plate on a tractor, displacing it sideways. This impact severed the aft skid attachment, allowing the skid assembly to rotate forward about 270°, and the helicopter slid to a halt on its right side.
The main rotor blades were reduced to root sections less than one metre long. Dense debris (tip weights, erosion strip fragments) was projected up to 150 metres. The bulk of the composite blades were shredded over a wide area. Light damage from debris was sustained by two vehicles, three parked aircraft, a fuel installation, and a hangar; one damaged vehicle was outside the airport perimeter. No evidence indicated any components separated before initial ground contact.
Helicopter Examination
The cabin structure was complete with no permanent distortion or intrusion; transparencies were slightly damaged. No pre- or post-impact damage was found in the flying control system. Cyclic and collective controls from pilot inputs to hydraulic servos were correctly connected and functional. The hydraulic pump/reservoir unit was tested: after replenishing hydraulic fluid and achieving sufficient shaft speed, the low pressure warning light extinguished, and full control range was observed. No hydraulic leakage was evident.
Weight and Balance
The helicopter's maximum authorized weight was 1,715 kg. Equipped Empty Weight was 1,058.5 kg with a CG at 4.183 metres aft of the datum (datum defined as 4 metres forward of mast centroid). No weight or balance exceedances were noted in the report.
Certification
The EC 120B is certified under JAR 27. The manufacturer stated that during certification, personnel weight of 80 kg was used, and the most critical wind condition was a left tailwind. The maximum demonstrated wind at critical CG was 30 knots (JAR requires 17 knots), which was not considered limiting. The Approved Flight Manual contains no specific wind limitations but states compliance with JAR 27.