TYPE: Agricultural sprayer.
PROGRAMME: Developed as stretched AT-401. First flight of AT-502 April 1987; certified 23 June 1987.
CURRENT VERSIONS: AT-502: Original version.
Description refers to AT-502, and is generally as for AT-401, except that below.
AT-502A: Similar to AT-502B but with 820 kW (1,100 shp) PT6A-45R; slow turning (1,425 rpm) five-blade Hartzell (HCB5MP-3C/M10876AS) propeller; enlarged vertical tail surfaces. For operation in mountainous terrain or short strips. Prototype first flight February 1992; certified April 1992; 26 delivered by end 2002.
AT-502B: Stronger wing than AT-502, with 0.61 m (2 ft) longer span and Hoerner wingtips, which are stated to increase width of spray pattern by 0.91 m (3 ft).
AT-503A: Dual control, tandem-seat trainer; PT6A-34AG engine. Prototype designated AT-503. In low-rate production.
CUSTOMERS: Total of 549 AT-500 series delivered by December 2002, including out-of-production AT-501 (nine), AT-502 (208), AT-503 (one), plus AT-503A (three). Production continued in 2003. Total 666 AT-500/AT-600 family built by mid-2003.
COSTS: Standard AT-502B US$594,500 with PT6A-15AG, or US$639,900 with -34AG; or US$299,900 with customer-supplied PT6A-15AG, -27, -28, -34AG (2003).
DESIGN FEATURES: See AT-401. 1,892 litre (500 US gallon; 416 Imp gallon) hopper handles low-density nitrogen-based fertilisers such as urea; safety glass centre windscreen with wiper. Alloy steel lower spar cap and bonded doubler on inside of wing leading-edge for increased resistance to impact damage, and glass fibre wingroot fairings.
LANDING GEAR: Non-retractable tailwheel type. Heavy-duty E-4340 spring steel main gear, thickness 37.2 mm (1.31 in); flat spring for castoring and lockable tailwheel. Cleveland mainwheels, tyre size 29x11.0-10, pressure 3.45 bar (50 lb/sq in); tailwheel tyre size 5.00-5; Cleveland six-piston with heavy-duty discs.
POWER PLANT: One 507kW (680 shp) Pratt & Whitney Canada PT6A-15AG, PT6A-27 or PT6A-28, or 559 kW (750 shp) PT6A-34 ot PT6A-34AG turboprop, driving a Hartzell HCB3TN-3D/T10282+4 three-blade metal propeller. Standard fuel capacity 644 litres (170 US gallons; 142 Imp gallons). Optional capacities 818 litres (216 US gallons; 180 Imp gallons) and 886 litres (234 US gallons; 195 Imp gallons). AT-502A has 818 litre (216 US gallons; 180 Imp gallons) tanks as standard.
ACCOMMODATION: One or two persons (see Current Versions). Has quickly detachable instrument panel and removable fuselage skin panels for ease of maintenance.
SYSTEMS: Two 24 V 42 Ah batteries and 250 A starter/generator.
AVIONICS: Comms: Optional avionics include Bendix/King KX 155 nav/com/glideslope and KR 87 ADF, KY 196 VHF radio, KT 76A transponder and ACK E-01 emergency locator transmitter.
EQUIPMENT: Agricultural dispersal system comprises a 1,892 litre (500 US gallon; 416 Imp gallon) hopper mounted in forward fuselage with hopper window and instrument panel-mounted hopper quantity gauge; 0.97 m (3 ft 2 in) wide Transland gatebox; Transland 6.4 cm (2½ in) bottom loading valve; Agrinautics 6.4 cm (2½ in) spraypump with Transland on/off valve and five-blade variable-pitch plastics fan and 38-nozzle stainless steel spray system with streamlined booms. Optional dispersal equipment includes 7.6 cm (3 in) spray system with 119 spray nozzles, and automatic flagman; spray swath 25.91 m (85 ft 0 in).
Standard equipment includes safety glass centre windscreen panel, ground start receptacle, three-colour polyurethane paint finish, strobe and navigation lights; windscreen washer and wiper; and twin nose-mounted landing/taxi lights. Optional equipment includes engine-driven air conditioning system, night flying package, comprising night working lights, retractable 600 W landing light in port wingtip; fuel flowmeter, fuel totaliser and ferry fuel system. Alternative agricultural equipment includes Transland 22356 extra-volume spreader, Transland 54401 NorCal Swathmaster, 40 extra spray nozzles for high-volume spraying, and eight- or 10-unit Micronair Mini Atomiser unit; hopper rinse tank is standard. New crew seat is also optional.