A role almost unique to New Zealand was the Ag-Dak. The use of DC-3's for top dressing was pioneered by James Aviation. Ossie James saw the increased efficiency in using a larger aircraft when most topdressing was being carried out with Tiger Moths and Austers. He convinced the government to part with an RNZAF aircraft in May 1954 (c/n 16568/33316 NZ3545 ZK-AZL), and after civil conversion by de Havilland at Rongotai, the aircraft was modified for its new role in Hamilton. The first load was dropped on December 1, 1955, and the concept was so successful that other companies chartered the aircraft. James Aviation also pioneered the conversion to allow single pilot operations in 1959, with changes to the undercarriage and flap controls, and the addition of hopper controls. At a 29000lb MTOW, the aircraft carried a 5 ton load. Fixed static loaders were eventually fitted at the aerodromes frequented by the ag-daks, some of which were in remote areas. (James Aviation are reported to have provided vehicles (Fiat 500 Bambina/ BMC Mini) loaded through the cargo door for operators away from home). Thirteen aircraft were eventually used in this manner. In 1960 James Aviation, Rural Aviation, and Fieldair formed 'Airland', who took over use of AZL. Airland purchased a number of DC-3 aircraft for conversion. ZK-BYF (c/n 20051) went into service on Mar 4, 1961, followed by ZK-CHV (c/n 17093/34360) on Sep 21 1964, ZK-APB (c/n 15945/32693) on December 8 1965, ZK-CQA (c/n 14585/26030) on August 13, 1966, ZK-AWO (c/n 33480/16732) on October 15 1968, and ZK-APK (c/n 34227/16967) on October 13, 1970. James Aviation had reclaimed AZL in 1963, and purchased a further aircraft , ZK-AOI (c/n 34226/16966) in December 1966 which worked for a short period in early 1967. This aircraft was stored in Hamilton till June 1970, when it worked from Ardmore and Rukuhia, and then in early 1971 went into service for James Aviation's subsidiary Southern Super Air. Fieldair began acquiring there own ag-daks, when ZK-BKD (c/n 13521) went into service on Aug 28 1971, and ZK-CAW (c/n 18293) on Nov 22 1972. James Aviation put two more aircraft into service. ZK-AZA (c/n 27144/15699) entered service on March 5 1973, and ZK-AWP (c/n 33135/16387) on July 27. The latter was a replacement for AOI which had crashed near Clarence on February 23, 1973 after the starboard wing seperated from the aircraft. The last ag-dak to enter service was ZK-BBJ (c/n 16962/34222) which had been purchaed by Fieldair in October 1971, but was not converted until December 1974. By this stage, the early ag-daks were being phased out of service. Age and economic changes were catching up with the aircraft. AZL was retired in September 1974, CQA (July 8, 1975), CHV (March 29, 1979), AZA (October 10, 1979), BYF (June 20, 1981), APK (July 3, 1981), APB (November 16, 1981), BKD (23January, 1983), AWO (March 1, 1984), CAW (October 29, 1984) and AWP (May 27, 1985). Fieldair absorbed the Airland operation in 1978, so from 1979 they were the sole ag-dak operator. The last of the ag-daks was ZK-BBJ, which Bruce Thompson worked from Gisborne until May 1987, when it was flown to Palmerston North to be converted to a freighter. (The fates of these aircraft are described in the survivors section below).
