Background
The aircraft involved, a Cessna A152 (registration G-BHAC), was manufactured in 1978 and powered by a single Lycoming O-235-L2C piston engine. The flight was a private trip with a crew of one and one passenger. The pilot, aged 60, held a Private Pilot’s Licence and had 116 total flying hours, of which 114 were on the type. His recent flying experience included 12 hours in the last 90 days and 6 hours in the last 28 days.
History of the Flight
On the morning of the accident, the pilot and passenger arrived at Shobdon, intending to fly to Caernarfon Airfield and return later. The pilot had not previously flown to Caernarfon but had visited as a passenger three years earlier. After checking weather via the flying club’s internet, they departed Shobdon at approximately 1100 hrs, flying via Colwyn Bay and the Menai Straits, arriving at Caernarfon at 1200 hrs. The pilot reported en-route conditions at 2,500 ft as good, with little cloud, hazy visibility, and no turbulence.
After lunch, they observed increased cloud cover and discussed the return route. At 1505 hrs, they departed Caernarfon on a southerly heading, intending a direct return. However, the pilot recalled nothing after takeoff due to injuries; subsequent events are based on radar data and witnesses.
Ground radar showed the aircraft heading south, but about 10 minutes later the pilot transmitted that he was returning to Caernarfon due to inability to penetrate weather to the south. He landed back at 1530 hrs and announced plans to return via the northern coast of Wales after refueling. The aircraft was refueled to full tanks. A recently departed aircraft provided a weather update indicating the Menai Straits were negotiable beneath cloud until Bangor, where the cloudbase was 3,000 ft with unlimited visibility.
At 1605 hrs, G-BHAC took off from Runway 26, turned right, and tracked approximately 070°M, climbing to 1,800 ft amsl. At 1611 hrs, the pilot contacted RAF Valley ATC for a Flight Information Service, requesting a heading of 190° at 1,800 ft, routing to Shobdon via Colwyn Bay. The controller corrected a misread QNH, which the pilot acknowledged. No further transmissions were received.
Approximately five minutes later, a fell runner near Bethesda heard an aircraft flying close but could not see it due to low cloud. The engine sounded normal, then pitched up for a few seconds, followed by a bang and silence. She alerted rescue services. At 1745 hrs, a Police Air Support Unit helicopter located the wreckage; the pilot was flown to hospital, and the passenger was fatally injured.
Meteorology
An aftercast from the Met Office indicated a moist south-westerly flow over the British Isles, with a slow-moving frontal band covering Ireland and the south-west approaches. In the accident area, wind at 2,000 ft was estimated from 330° at 15 kt, with a broken strato-cumulus cloud base at 1,700 ft amsl, likely more extensive over high ground. Surface visibility was 15-20 km. RAF Valley, 20 miles west, reported at 1550 hrs visibility better than 10 km and a broken cloudbase at 1,700 ft agl.
The Met Office Form 215 forecast for 1400-2300 hrs indicated visibility generally 15 km with haze reducing to 7 km, occasionally to 3,000 m in mist or drizzle, and isolated sea and hill fog. Broken strato-cumulus base between 1,500 and 2,000 ft amsl was forecast, with occasional broken stratus base between 200 and 700 ft amsl. The TAF for RAF Valley forecast visibility over 10 km and small amounts of cloud at 2,000 ft amsl.
The fell runner reported the cloudbase at approximately 2,000 ft, with significant drop in the preceding two hours and little wind. Other aircraft reported a cloudbase in the Menai Straits of about 1,000 ft amsl with 15 km visibility; one aircraft noted that the Snowdonia mountains were obscured by low cloud.
Pathology
The post-mortem examination of the passenger determined the cause of death as aspiration of stomach contents into the airways. The aviation pathologist stated that the passenger sustained injuries in the crash, but none were necessarily fatal, and the pilot survived similar injuries. No additional safety equipment would have changed the outcome.
Impact Conditions
The aircraft struck gently rising ground at approximately 1,970 ft amsl, near the local summit, on a track of about 070°M. Ground impact features and deformation patterns indicated the aircraft was in substantially level flight, banked approximately 10° to the left, and pitched slightly nose up relative to its flight path, which was horizontal at impact. Forward momentum caused the wings to move forward and swing downward, and the cabin roof and wings lay just above the engine cowl. The left wing rear spar attachment fittings failed in overload due to inertial in-plane loading. These deformations indicated a substantial impact velocity in the horizontal plane, consistent with normal level flight at impact.
Wreckage Examination
In-situ inspection showed the fuel valve selected ON. The left wing fuel feed pipe was broken due to rotational wing movement. The right fuel tank was empty; the left tank contained a small quantity of fuel to the outlet level, with fuel likely draining from the left tank via the fractured pipe and from the right tank through the same fracture. The throttle linkage was damaged; the carburettor lever could have been driven toward the throttle-closed position during impact, so the throttle setting at impact could not be determined. The mixture control was at fully rich, and the hot air control was set to COLD. The alternator showed rotational scoring, indicating the engine was running at impact.