History of the Flight
The Vans RV-9A, registration G-CCGU, departed at 1200 hrs for a short local flight before a planned departure to Dunkeswell. On return, the pilot positioned to land on Runway 06 at Henstridge Airfield. The pilot turned finals at approximately 500 ft agl and considered the approach normal. Having operated from Henstridge since 2006, the pilot was aware of the road crossing the Runway 06 undershoot but did not observe any vehicles at the start of the approach.
Shortly before touchdown, the pilot saw a heavy goods vehicle (HGV) very close to the right of the aircraft. The right wingtip struck the rear of the HGV trailer. The HGV was crossing the undershoot from left to right. The pilot recalled nothing further until noticing the aircraft inverted on the ground with the canopy broken. A roll bar kept the cockpit off the ground, and the harnesses restrained both occupants. A car following the HGV stopped, and its occupants helped break canopy perspex to clear an exit path. Ambulance personnel from the Air Ambulance base at Henstridge arrived quickly, followed by local emergency services. There was no fire. Both occupants were taken to hospital by ambulance; the pilot was released that evening with minor injuries, while the passenger remained in hospital for three days due to a broken wrist requiring surgery.
Accident Site
The collision occurred at the unlicensed Henstridge Airfield in Somerset. The aircraft was approaching Runway 06, which is 728 m long with a threshold displaced by 22 m. The access road leads to an industrial site south of the airfield and sees significant traffic, including approximately 300 HGV movements per day. The road converges with the runway centreline from the left at an angle of about 20°. The low wing configuration of the aircraft and the HGV's shallow-angle convergence likely impeded the pilot's view of the road. The accident site was about 70 m from the runway threshold.
Obstruction Clearance Information
For licensed airfields, CAP168 specifies obstacle clearance requirements. According to ICAO guidance, all roads are considered obstacles extending to 4.8 m above the crown of the road. Obstacles must not penetrate a surface that begins 30 m from the threshold and has a 1 in 20 slope. At Henstridge, the collision occurred about 70 m from the threshold; any obstacle more than 2 m tall would penetrate the clearance surface. A 3° approach path from the threshold would cross the road at 3.7 m agl. As Henstridge is unlicensed, it need not comply with CAP168.
Safety Action
In response, the airfield operator displaced the threshold of Runway 06 by an additional 100 m. The incident site is now about 170 m from the threshold, the obstacle clearance surface is 7 m above the road, and the approach complies with CAP168 obstacle clearance requirements. A 3° path from the new threshold would cross the road at about 9 m agl.
Analysis
The pilot recalled a normal powered approach. The aircraft struck the top of the HGV, indicating it was about 4 m above ground, consistent with a 3° approach. The road's shallow convergence angle and the aircraft's low wing made it unlikely the pilot could see the HGV during the approach. Upon crossing the road, the pilot saw the HGV very close and had no time to avoid. The aircraft struck the HGV and came down inverted. The roll bar protected the occupants, and they exited with bystander assistance.
Conclusion
The aircraft struck an HGV in the latter stages of approach to Runway 06 at Henstridge Airfield and came down inverted on the road short of the runway. Both occupants escaped. The pilot sustained minor injuries; the passenger suffered a broken wrist. The airfield operator's safety action makes the approach compliant with obstacle clearance provisions of CAP168, though not required for an unlicensed airfield.