Ferranti, had x2.5 and x10 magnification. The APX Bezu sight unit was also evaluated but rejected, although it was adopted for use on the Westland Wasp. Additional testing and trials were carried out with the Swingfire anti-tank guided missile. Initial firings were carried out in early 1972, to test the "Hawkswing" system for the Westland Lynx, the associated AF.530 gyro-stabilized sight was subsequently trialled in 1974. The Hawkswing system was cancelled in 1975 due to its manual command to line of sight (MCLOS) compared to the semi-automatic (SACLOS) system used by the MILAN missile. In the casualty evacuation role (CASEVAC), the Scout could carry two stretchers internally or two on externally mounted pods, the co-pilot's seat could also be reversed to allow an attendant to face the casualties. Although the general design of the aircraft was robust, with an airframe fatigue life of 7,200 hours, the cockpit ergonomics were less than perfect. An example of this was the cabin heater switch being mounted next to the fuel cock; this led to the loss of at least four aircraft when the pilot inadvertently closed the fuel cock instead of switching off the cabin heater, causing the engine to shut down. The autorotational qualities of the Scout have also been described by some pilots as 'startling'. In service trials and testing were carried out by the AAC's Development Wing at Middle Wallop, Hampshire. A wide variety of weapons and equipment were evaluated, although many were never adopted. Amongst these were the 7.62mm General Electric Minigun and the two-inch rocket pod. The rocket pods were mounted either side of the central fuselage section on the multi-spar weapon booms and both smooth tube and fin-stabilised rockets were tested, although the accuracy was described as "indifferent". Studies were also carried out for a pintle-mounted M2 Browning machine gun in place of the standard 7.62 GPMG, and the French AME.621 20mm cannon. Another was the installation of a Bendix R.100 lightweight weather and ground-mapping radar, which had a range of eight and 40 miles. This was mounted behind the fibreglass nose access panel along with a small viewing screen in the cockpit. The radar antenna was moved further forward later in the development to improve downward scanning. During the development of the WG.13 Westland Lynx, two Scouts were used as testbeds and fitted with full-scale, composite construction semi-rigid Lynx main rotor heads as the Scout had