Photograph:
Air Tractor AT-400 VH-ACQ (c/n 400-0285) at Moree, NSW (David C Eyre)
Country of origin:
United States of America
Description:
Single-seat agricultural monoplane
Power Plant:
One 507 kw (680 shp) Pratt & Whitney PT6A-15AG turboprop
Specifications:
- Wingspan: 14.97 (49 ft 1¼ in)
- Length: 8.99 m (29 ft 6 in)
- Height: 2.59 m (8 ft 6 in)
- Wing area: 25.08 m² (270 sq ft)
- Max speed at sea level in clean condition: 322 km/h (200 mph)
- Cruising speed at 55% power at 2,440 m (8,000 ft): 264 km/h (164 mph)
- Normal operating speed: 209 – 233 km/h (130 – 145 mph)
- Stalling speed flaps down, at 2,721 kg (6,000 lb): 99 km/h (61 mph)
- Max rate of climb at sea level: 495 m/min (1,625 ft/min)
- Max rate of climb at 3,565 kg (7,860 lb): 247 m/min (810 ft/min)
- Landing run: 122 m (400 ft)
- Empty weight: 1,696 kg (3,739 lb)
- Normal loaded weight: 2,721 kg (6,000 lb)
- Max operating weight: 3,538 kg (7,800 lb)
History:
By 1981 the advantages of turbine-powered aircraft in the agricultural field were being realised throughout the world. Companies producing large agricultural aircraft considered ways of fitting their designs with turbine power plants to take advantage of more economical operation. In September 1976 Air Tractor commenced to design the Model AT-302, which was basically similar to the AT-301 except for the installation of a Lycoming turboprop engine in lieu of the radial unit. Structural modifications were necessary for the installation of the new engine.
In 1979 a new model was introduced, known as the AT-302A. The hopper size had been increased from 1,211 litres (266.3 Imp gals) to 1,514 litres (333 Imp gals), and a 0.97 m (3 ft 2 in) wider gatebox had been fitted for higher application rates of dry chemicals. The Lycoming engine fitted was the LTP-101-600A1 providing 448 kw (600 shp). Max cruising speed of the AT-302 and AT-302A was 266 km/h (165 mph) and max take-off weight was 3,266 kg (7,200 lb). Shortly after a new model appeared, the AT-400, incorporating the larger hopper and gatebox of the AT-302A, but fitted with the more powerful 507 kw (680 shp) Pratt & Whitney of Canada PT6A-15AG turboprop driving a three-blade Hartzell propeller.
The first piston-engine example of the AT-301 was registered in Australia in 1979, and the first AT-400 was placed in service by Aircair of Moree, NSW in 1981. This aircraft, VH-ACQ, the second of the type to be delivered by the manufacturer, entered service on cotton spraying operations in north-west New South Wales. In later years the AT-402 model was developed and, although only one example of the AT-400 has been registered in Australia, a number of AT-402s have entered service.
At one stage New Zealand operators sought a new model with a second seat for the ground-crew member, and this model became the AT-402B, the rear cockpit area being re-designed and a seat installed. Access was via a door on the left-hand side of the canopy. The first AT-402B imported became ZK-SAT (c/n 402B-0992), this change to two-seat configuration being an option thereafter on the manufacturer’s production line. Later the AT-402A model was fitted with the Pratt & Whitney PT6A-11AG engine of 410 kw (550 shp) and was basically a lower-cost model, the first of this model to arrive being VH-PTG (c/n 402A-1035).
The turbine version was the AT-402, the prototype (N1005V) flying in December 1988 with a 507 kw (680 shp) PT6A-15AG engine. This was followed by the AT-402A, the first of which (N10189) flew in January 1990 with a 410 kw (550 shp) PT6A-11 turboprop.
Examples registered in Australia have included: Model AT-402A VH-PTG (c/n 402A-1035); Model AT-402 VH-LRK (c/n 402-0826); Model AT-402A VH-PTS (c/n 402A-1101); Model AT-402 VH-ZYF (c/n 402-0788); and Model AT-402B VH-FLD (c/n 402B-1165).
New Zealand registered AT-402Bs have included: ZK-JHG (c/n 402B-1021), ZK-PCC (c/n 402B-1049) and ZK-SAT (c/n 402B-0990).