the latter half of 1964. The third prototype participated in a series of accelerated wear trials to establish component endurance and overhaul lifespan, while the fourth prototype was assigned to further tests of equipment for the naval environment. By July 1964, the French Government had placed an initial order for the Super Frelon, intended to perform logistic support duties at the Centre Experimental du Pacifique; negotiations for a further order was already being negotiated for the naval version, which were to be equipped for anti-submarine duties. However, West German support for the Super Frelon programme had already declined by this point, partially due to interest in the rival Sikorsky SH-3 Sea King, which was evaluated against the type. Both civilian and military versions of the Super Frelon were built, with the military variants being the most numerous by far, entering service with the French military as well as being exported to Israel, South Africa, Libya, China and Iraq. Three military variants were produced: military transport, anti-submarine and anti-ship. The transport version is able to carry 38 equipped troops, or alternatively 15 stretchers for casualty evacuation tasks. Design The Aérospatiale SA 321 Super Frelon is a large, heavy-lift single-rotor helicopter, furnished with a relatively atypical three-engine configuration; these are Turboméca Turmo IIIC turboshaft engines set on top of the fuselage, a pair of turbines positioned side by side at the front and one located aft of the main rotor. The naval anti-submarine and anti-ship variants are usually equipped with navigation and search radar (ORB-42), and a 50-metre rescue cable. They are most often fitted with a 20 mm cannon, countermeasures, night vision, a laser designator and a Personal Locator System. The Super Frelon can also be fitted for inflight refueling. The front engines have simple individual ram intakes, while the rear one is fitted with a semi-circular scoop to provide air; all three bifurcated exhausts are near to the rotor head. The three engines and the reduction gearbox are mounted on a horizontal bulkhead and firewall which forms the roof of the cabin and upper structural member of the fuselage. The engines are isolated by multiple firewalls, including transverse firewalls separating front and rear engines from the rotor gearbox, and zonal engine firewalls. Eight sturdy hinged doors provide access to the compact Turmo engines, which have ample space around them to enable ground crew to service them without using external platforms.