History of the Flight
The aircraft, an Avions Pierre Robin DR400-180 (registration F-GDYD), departed from Chavenay, France, on a seven-day journey to Oshkosh, USA, to attend the Experimental Aircraft Association's Fly-In Convention. The first leg to Cherbourg was uneventful, where the aircraft was refuelled to full tanks (350 litres). The pilot amended the flight plan to Inverness because Stornoway, the planned stop, was due to close before their estimated arrival.
Departing Cherbourg at 1110 hrs, the aircraft flew north over the English Channel at 3,000 ft amsl on a direct track to Bournemouth, feeding fuel from the main tank. After passing Bournemouth, it climbed to FL65 towards Welshpool. At level, the pilot selected fuel from the left wing tank. Forty litres from the main tank had been consumed, leaving 70 litres. The wing tanks each held 40 litres; the crew intended to run the left tank dry to refine fuel consumption calculations made two weeks earlier.
After 20 minutes at FL65, the crew requested clearance to FL85 to avoid cloud but were denied, so they descended below cloud base to between 2,500 ft and 3,000 ft amsl. The route continued east of Bristol, over Welshpool, towards Rhyl. Throughout, carburettor heat was applied every five minutes, with rpm dropping and recovering when returned to COLD. After descent, the co-pilot noted the carburettor temperature gauge in the amber band, indicating icing risk, and selected HOT; the temperature moved above the amber band, engine rpm reduced 100 rpm then recovered.
While manoeuvring to avoid high ground north of Welshpool, the pilot altered course left. The left wing tank low-level warning light illuminated; the pilot estimated 15 minutes of fuel remaining. The engine suddenly ran down to 1,500 rpm. The pilot switched the electric fuel pump ON and moved the fuel selector a quarter turn anti-clockwise to the main tank, expecting recovery in one or two seconds. The co-pilot recalled the selector move before the pump and that the fuel pressure gauge read similarly before and after. The engine did not accelerate, so carburettor heat was selected HOT. The engine still did not restart, though the propeller windmilled. The pilot lowered the nose to 230 kph (127 kt) and moved the selector further anti-clockwise to the right wing tank. He exercised the throttle and confirmed mixture RICH. Later, the pilot was unsure whether he left the selector on the right tank or returned to main. He had no indication of electric fuel pump operation but did not recall a low pressure light.
The aircraft descended from 700-800 ft agl; the pilot selected a field for forced landing, continuing to exercise the throttle. He approached but did not recall selecting flap. Just before touchdown, the co-pilot switched off the magnetos. After a gentle touchdown, the aircraft yawed left; the pilot applied full right rudder. The aircraft descended into a depression in the far corner, struck a bank nose-first, yawed further left, and came to rest upright but substantially damaged. Both crew suffered serious leg injuries.
Post-Accident Response
A householder 200 metres away heard the forced landing and called emergency services, staying with the crew until help arrived. Other members of the public also assisted. There was a significant fuel leak but no fire. All three emergency services attended; both crew were airlifted to hospital and later recovered. The Emergency Locator Transmitter was triggered and switched off by an air ambulance crew member, who also located the battery for the fire crew, who removed it. Fire services laid two layers of foam for safety.
Recorded Data
Four independent GPS units were recovered and downloaded. One was panel-mounted; three were handheld, two in the wreckage and one nearby. Each logged GPS position over time; some recorded altitude, groundspeed, and heading. Radar data from Clee Hill and St Annes provided aircraft position and pressure altitude corrected by QNH 1,009 mb to give altitude amsl (approximate due to 100 ft resolution).
At 13:27:23, the aircraft was 15 nm from the accident site at 3,300 ft amsl. Over eight minutes, it descended to 2,500 ft over rising terrain, at one point 415±50 ft agl. At 13:35:07, GPS groundspeed indicated suspected power loss; radar confirmed descent from 2,500 ft amsl at 13:35:16. Airspeed decayed from 98 kt, then stabilised at 74 kt with a rate of descent of about 900 ft/min. The aircraft passed over Llanfihangel Glyn Myfyr at 13:36:28 at GPS altitude between 1,375 ft and 1,530 ft amsl.
Using three GPS units and ground marks, touchdown was estimated at 13:36:58 with a groundspeed of about 63 kt at terrain elevation 1,230 ft amsl. Over 111 seconds from suspected power loss to touchdown, the average rate of descent was 680 ft/min over 2.5 nm.
Meteorological Conditions
A Met Office aftercast indicated high pressure over the eastern Atlantic and low pressure over the North Sea, with fresh to strong Polar Maritime airflow over Wales. Visibility was about 25 km, reducing to 6 km in showers and under 200 metres in cloud and hill fog. The pilot recalled outside air temperature of 17°C, no rain, and blue sky ahead. At that temperature, moderate icing risk at cruise power and serious icing at descent power.
Aircraft Information
The Robin DR400-180 is a predominantly wood monoplane with fabric covering, a cranked wing, and sliding perspex canopy. It has tricycle landing gear and seats four in normal configuration. The accident aircraft had a 110 litre main fuselage tank under the rear seat, a 50 litre supplementary tank in the rear fuselage, and 40 litre wing root tanks. It was modified with an additional fuel tank replacing the rear seat for extended range.