Description

On 11 February 2009, two civil registered Grob 115E Tutors being operated for the UK Royal Air Force (RAF) and based at RAF St Athan near Cardiff were conducting Air Experience Flights (AEF) for air cadet passengers in uncontrolled airspace near Porthcawl in day Visual Meteorological Conditions (VMC) when they collided. Both aircraft were sufficiently damaged that they could no longer be controlled and they impacted the ground in the vicinity of the collision killing both pilots and both passengers and resulting in a fuel fed fire in one of the aircraft.

Investigation

An Investigation into the accident was carried out by the UK AAIB. It was established that the two aircraft, which had both been aware of the presence of a second AEF aircraft in the vicinity, had collided at an altitude of approximately 3,000 feet when within the normal operating area for RAF St Athan AEF sorties to the north-west of Cardiff Airport located between about 10 and 20 nm from St Athan. One aircraft had been on a westerly heading whilst the other had been closing from the south, probably whilst still turning left. The pilots of both aircraft were qualified military pilots and had been occupying the right hand seats of their respective aircraft.

It was determined that the right hand wing of the turning aircraft had struck the aft fuselage of the other, which had then become detached from the aircraft. The right wing of the other aircraft also appeared to have detached at, or very soon after, the point of collision. Both aircraft were thus rendered uncontrollable.

It was noted that the operating area for the St Athan AEF flights was restricted by a number of factors, some of which were unique to St Athan. These resulted in the AEF flights routinely operating in a relatively small area. At the time of the collision, there were no specific operating procedures in place to ensure AEF aircraft de-confliction from each other either before or during flight. The RAF has subsequently recommended that specific de-confliction measures be introduced.

It was noted that control of AEF flying was the responsibility of the RAF’s Number 1 Elementary Flying Training School, headquartered at RAF Cranwell, Lincolnshire and that the 12 UK AEFs were co-located and incorporated within 14 University Air Squadrons based at 12 locations. It was noted that AEFs are established to provide cadets with powered flying experience in an RAF environment. In accordance with normal practice, all four occupants were wearing parachutes, but their deployment had not been attempted.

It was also noted that an RAF Service Inquiry had been convened under the provisions of Section 343 of the Armed Forces Act 2006 and the Panel thereby constituted had made a total of 15 recommendations to its convening authority after working in parallel with the AAIB Investigation. These Recommendations included the following:

• On De-confliction: “Measures should be identified and implemented to deconflict flights from all AEF units based on unit activity, tasking, ATS availability, local flying area and period of operations”.
• On Collision Warning Systems: “… consideration be given to fitting a suitable collision warning system to the RAF Tutor aircraft”.
• On Aircraft Conspicuity: - a review of the previous Tutor conspicuity options and alternative colour schemes should be undertaken to determine what measures to improve the aircraft’s conspicuity are technically possible and practical.
• On Survival Training: - RAF Tutor emergency egress and parachute training should be reviewed to ensure motor actions required to jettison the canopy and deploy the parachute are reinforced.

The Service Inquiry also made further recommendations in areas including lookout training, Service policy on contact lenses, cockpit design of the Tutor and future aircraft, and notification to other airspace users about AEF flights.

The AAIB Findings included the following:

• Neither pilot was in contact with ATC, and was not required to be
• Neither aircraft was equipped with an electronic CWS
• The primary method of collision avoidance was visual - see and be seen
• The physical size of the Tutor, together with its all white colour scheme would have made it difficult to acquire visually in the prevailing conditions
• It is likely that each aircraft was physically obscured from the other pilot’s view at various times leading up to the collision, thus opportunities to visually acquire the other aircraft were limited for both pilots
• Neither aircraft appeared to take avoiding action

The AAIB Investigation identified the Causal Factor of the accident as being that:

• Neither pilot saw the other aircraft in time to take effective avoiding action, if at all.

Four Contributory Factors were also identified by the Investigation:

1. The nature of the airspace and topography of the region reduced the available operating area such that the aircraft were required to operate in the same, relatively small block of airspace.
2. There were no formal procedures in place to deconflict the flights, either before or during flight.
3. The small size of the Tutor and its lack of conspicuity combined to make visual acquisition difficult in the prevailing conditions.
4. At various stages leading up to the collision, each aircraft was likely to have been obscured from the view of the pilot of the other aircraft by his aircraft’s canopy structure.

In view of “the wide-ranging recommendations” made by the parallel RAF Service Inquiry, the AAIB considered that no further Safety Recommendations were necessary.

The Final Report of the Investigation was published on 3 November 2010

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