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Photograph:
Air tractor AT-504 VH-FFS (c/n 504-4009) at the Australian international Airshow at Avalon, VIC on 25 February 2015 (David C Eyre)
Country of origin:
United States of America
Description:
Two-seat turbine-powered agricultural training aircraft
Power Plant:
One 559 kw (750 hp) at 2200 rpm Pratt & Whitney PT6A-34AG turboprop
Specifications:
- Wingspan: 15.84 m (52 ft)
- Length: 9.91 m (23 ft 6 in)
- Height: 2.99 m (9 ft 9½ in)
- Wing area: 29.01 m² (312 sq ft)
- Cruising speed at 2,438 m (8,000 ft): 243 km/h (151 mph)
- Working speed: 193 km/h to 233 km/h (120 to 145 mph)
- Stalling speed flaps up: 121 km/h (75 mph)
- Stalling speed flaps down at 3,629 kg (8,000 lb): 105 km/h (65 mph)
- Landing speed: 85 km/h (53 mph)
- Take-off distance: at 4,354 kg (9,600 lb) 351 m (1,150 ft)
- Rate of climb: 262 m/min (860 ft/min)
- Fuel capacity: 643 litres (141 Imp gals)
- Optional tanks providing capacity: 817 litres (180 Imp gals) or 885 litres (195 Imp gals)
- Range at economical cruising speed: at 2,438 m (8,000 ft) 978 km (608 miles)
- Hopper capacity: 1,893 litres (416 Imp gals)
- Empty weight: 1,950 kg (4,297 lb)
- Useful load: 2,150 kg (4,740 lb)
- Landing weight: 3,629 kg (8,000 lb)
- Loaded weight: 4,354 kg (9,600 lb)
History:
In about 2007 Air Tractor found there was a growing interest within the agricultural industry to train and prepare replacements for pilots who had been in the industry for many years and were coming to retirement time. Leland Snow set out to solve the problem and designed the AT-504 to meet the industry’s needs. Basing the design on the tried and proven AT-502B airframe, the aircraft utilised the same PT6A-34AG turboprop engine. The aircraft has been described as “a superior platform for aerial application and instruction without sacrificing performance or flight characteristics”.
The initial design of the AT-504 came about because of a requirement imposed by the Chinese Government to obtain an agricultural type aircraft from Air Tractor, the requirement being to acquire an aircraft with side-by-side seating to assist in the transition of military pilots into the field of agricultural aviation. Initially the single-seat of an AT-502B was replaced by two seats to see if they would fit and, as they did, a new expanded canopy was designed and installed. Dual controls were installed and the new aircraft met the Chinese requirement.It has since met the requirements of other operators in the agricultural market.
Similar to the AT-502B, the AT-504 had additional wing structure that permitted the installation of Hoerner wing tips which increased the wingspan to 15.84 m (52 ft), this resulting in an increased rate of climb and swath width for higher productivity. A new hopper rinse system was standard equipment. The first aircraft was modified in 2008 and attended the National Agricultural Aviation Association Annual Convention in December of that year. Early deliveries were to Australia, Indonesia, China and Costa Rica. Power was provided by the PT6A-34AG engine providing 559 kw (750 hp) at 2200 rpm driving a Hartzell HC-B3TN-3D/T1028 NS+ four-blade propeller.
A number of examples have been imported for operation in this part of the world. First aircraft in New Zealand became ZK-SKF (c/n 504-4015) and was assembled at Timaru for SkyFarmers Aviation of Methven, this aircraft flying in New Zealand for the first time on 3 August 2012.
Examples in Australia have included VH-FFS (c/n 504-4009) for Field Air (Holdings) Pty Ltd of Ballarat, VIC; VH-FEC (c/n 504-1504) for Dunn Aviation of Jandakot, WA; and VH-WXE (c/n 504-4001) for AirCare Aviation of Moree, NSW.
Air Tractor designed a variant of the AT-504 for the border security and surveillance role, this aircraft being clean without any spraying equipment, air conditioned, having two pilots and having an FLIR mounted to the firewall which could be extended into the slipstream as required. The hopper was converted into a fuel tank and gave the aircraft over 15 hours of endurance with a cruising speed of 296 km/h (184 mph).