the only passenger operator of the CL-44J, variant of CL-44D4 stretched on request by Canadair. It was the largest passenger aircraft flying over the Atlantic Ocean at that time. Loftleiðir marketed the CL-44J under the name "Rolls-Royce 400 PropJet". This led to the confusion that the CL-44J is sometimes referred to as the Canadair-400. Loftleiðir Icelandic Airlines merged with Air Iceland in 1973 and became today's Icelandair. In 1981 a Baku, Azerbaijan-based Soviet Union interceptor deliberately rammed an Argentine Canadair CL-44 from Transporte Aéreo Rioplatense, killing the three Argentines and one Briton on board; the aircraft was delivering arms from Israel to Iran (the Soviet pilot ejected and survived). The CC-106 Yukons retired in March 1971 and were replaced by the Boeing 707 (CC-137). The Yukons might have served longer with the Canadian Forces Air Transport Command but for two factors: the need for an aircraft which could operate as an in-flight refueling tanker, and the chronic shortage and high cost of spares, the latter resulting because the CL-44 had never gone into large-scale production. All Yukons were sold to South American and African operators as they could not be registered in Northern America or Europe since the FAA refused to certify the original windshields which came from the Bristol Britannia because they did not meet flight crew vision standards. The General Dynamics CV880/990 windshields were compatible enough to be adopted into the flight deck structure, but the cost was prohibitive. The CC-106 had the original Bristol Britannia windshield and, on its retirement from RCAF operations, the cost of conversion was estimated at $250,000.00 per unit, cost alone precluding its use in North America and Europe. In 1974, a special exclusion was granted for the CC-106 (Cargo) for civil operations in Canada. Variants CL-44-6 Version built for the Royal Canadian Air Force as the CC-106 Yukon, 12 built CL-44D4-1 Civil, commercial cargo aircraft, civil prototype and production aircraft for Seaboard World Airlines, eight built. CL-44D4-2 Civil, commercial cargo aircraft originally built for Flying Tiger Line, 13 built. CL-44D4-6 Civil, commercial cargo aircraft originally built for Slick Airways, four built. CL-44D4-8 Civil aircraft for Icelandic Airlines Loftleidir, two built (civil passenger version) CL-44J Four CL-44D4 aircraft stretched by Canadair on request of Icelandic Airlines Loftleiðir, with a section, 10 ft 1 in (3.07 m) forward of the wing, and another section of 5 ft 1 in (1.55 m) aft of the