Pegasus Quik, G-CWIK, 12 May 2012

31� Crown copyright 2013 AAIB Bulletin: 1/2013 G-CWIK EW/C2012/05/02 ACCIDENT Aircraft Type and Registration: Pegasus Quik, G-CWIK No & Type of Engines: 1 Rotax 912 ULS piston engine Year of Manufacture: 2004 (Serial no: 8018) Date & Time (UTC): 12 May 2012 at 1013 hrs Location: 100 ft below summit of Ben More, Stirlingshire, Scotland Type of Flight: Private Persons on Board: Crew - 1 Passengers - 1 Injuries: Crew - 1 (Fatal) Passengers - 1 (Fatal) Nature of Damage: Aircraft destroyed Commander’s Licence: Private Pilot’s Licence (Microlights) Commander’s Age: 63 years Commander’s Flying Experience: 826 hours (of which 1 was on type) Last 90 days - 12 hours Last 28 days - 6 hours Information Source: AAIB Field Investigation Synopsis The aircraft was being flown by an experienced microlight pilot accompanied by the owner, who was a passenger, occupying the rear seat. They were transiting from Perth to Glenforsa, on the Isle of Mull, at about 6,000 ft, above scattered cloud. Approximately 2 nm east of Ben More mountain, in Stirlingshire, the aircraft descended in good visibility, remaining clear of the cloud. The descent and flight up to one second before impact was recorded on a video camera attached to the aircraft. The aircraft levelled off below the cloud base and approximately 100 ft above the summit of the mountain. It continued towards the mountain and encountered severe turbulence in the lee of the summit. This appeared to cause the pilot to lose control of the aircraft, which impacted the south side of the summit, fatally injuring both occupants. History of the flight A group of friends had agreed to fly from Perth Airport to Glenforsa, an airfield on the Isle of Mull, using four weight-shift microlight aircraft. The owner of G-CWIK had purchased the aircraft in October 2011 and was taking flying lessons in it. On the day of the accident the pilot and the owner (his passenger) arrived between 0700 and 0730 hrs and prepared their aircraft. G-CWIK had been refuelled the day before the accident and at about 0800 hrs the group met to discuss the flight. They would not be flying in formation, or as an organised stream, 32� Crown copyright 2013 AAIB Bulletin: 1/2013 G-CWIK EW/C2012/05/02 that the aircraft descended slightly, to about the same height as the summit and heading directly towards it, as if to pass over the top. The flight path appeared stable until about 300 m before the summit, when the aircraft began rolling from side to side, with some pitching motion. The engine speed increased significantly and the aircraft banked rapidly left and right and then pitched rapidly nose-down before impacting the mountain side. A witness on top of Ben More saw the last moments of the aircraft’s flight but did not see or hear the impact. He described the wind at the summit as “very strong” and that when he removed an item of clothing from his rucksack it was nearly “ripped” out of his hand by the wind. He did not realise that the aircraft had crashed; the noise of the wind had probably masked the sound of the impact. Shortly after this he met two other hill walkers and they came across the wreckage some time later. They reported the accident to the police, who mobilised the Search and Rescue response. Both occupants had been fatally injured. Aircraft description The Pegasus Quik is a tandem two-seat weight-shift microlight, powered by a Rotax 912 ULS piston engine driving a Warp Drive three-bladed propeller (Figure 1). Figure 1 Accident aircraft G-CWIK but would make their way independently, meeting at Glenforsa for lunch. According to the ATC movements log, the group of aircraft departed to the west, between 0917 and 0927 hrs with G-CWIK departing at 0920 hrs. The pilots described the weather at Perth when they departed as having good visibility, with scattered clouds at about 4,000 ft. One of the pilots later reported that he initially climbed to 4,000 ft, where he estimated, from his GPS groundspeed and his indicated airspeed, a headwind component of about 15‑20 mph with moderate levels of turbulence. Due to the turbulence, he climbed to between 6,000 and 7,000 ft, where the flying conditions were smoother. G-CWIK was last seen by one of the other aircraft at about 6,000 ft to the northeast of Ben More, where it was seen to descend. A GoPro Hero video camera, attached to G-CWIK and facing forward in the direction of flight, was later used by the investigation to reconstruct the later stages of flight. The final camera recording commenced 3 minutes and 21 seconds before impact and showed the aircraft descending above a small patch of stratus cloud, with the snow-capped summit of Ben More (elevation 3,850 ft amsl) clearly visible through a gap. The local terrain was visible in sunshine with the slow‑moving shadows of the scattered cloud. There was no smoke or other visual means to indicate the direction and strength of the wind, and no snow ‘spindrift’ 1 was being blown from the summit. The aircraft manoeuvred to the right and left avoiding entering cloud and then passed clear of the edge of a cloud, heading towards the top of the mountain. The aircraft levelled off and engine speed increased just below the cloud base, which was about 300 ft higher than the summit. The recording shows Footnote 1 Spindrift is the movement of the surface snow particles due to the effect of the wind. 33� Crown copyright 2013 AAIB Bulletin: 1/2013 G-CWIK EW/C2012/05/02 G-CWIK was fitted with the optional electric pitch trim system and the GoPro Hero video camera was mounted on the forward strut. The Permit to Fly had been renewed on 3 May 2012 and the airframe and engine had accumulated 438 hours. The wing, which had been replaced in July 2010 following an accident, had accumulated 62 hours. Accident site and wreckage examination The aircraft had struck Ben More mountain on its south‑eastern side 100 ft below the summit (Figure 2). The accident site was consistent with the aircraft having hit a small rock in a steep nose-down attitude with some left bank. The nosewheel and parts of the nose structure were embedded in the ground by the rock and the main aircraft wreckage was lying inverted 8 m away from the rock in the direction of 225°(M). The fuel tank had split and was empty but there was a distinct smell of fuel at the accident site. All three propeller blades had failed near the root. The wreckage was recovered from the mountain by helicopter on 16 May 2012 and then transported to the AAIB’s facility in Farnborough for more detailed examination. All the failures within the airframe and wing structure could be explained as a result of impact forces. The pylon had failed aft due to buckling loads which permitted the propeller to strike the wing. The aft end of the keel and the aft end of the fin tube had been deformed as a result of propeller strikes indicating significant energy in the propeller. All failures within the rigging were due to overload resulting from impact forces or propeller strikes. The electric motor for the pitch trim system was found set to ‘six turns’. According to the aircraft manufacturer this trim setting, with two occupants, would result in an approximate trimmed airspeed of 60 to 65 mph. Figure 2 Accident site location, 100 ft below summit of Ben More (image extracted from video camera fitted to G-CWIK) 34� Crown copyright 2013 AAIB Bulletin: 1/2013 G-CWIK EW/C2012/05/02 The lap straps from both seats had failed in overload. However, the harnesses on UK microlights are only required to restrain occupants in the case of 9.0g forward loading and 4.5g upward loading – the impact loads in this accident would have been considerably higher. Recorded data Devices from the aircraft A number of electronic devices were recovered from the accident site, including a GPS eTrex Legend C and a GPS-enabled iPad. However, the only relevant recordings that were recoverable were from the memory card of the GoPro Hero

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Pegasus Quik, G-CWIK, 12 May 2012

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