TYPE: Twin-turboprop transport.

PROGRAMME: Originally known as SD3-30; first flight of first prototype (G-BSBH) 22 August 1974; CAA certification to full Transport Category 18 February 1976; US FAR Pt 25 and Pt 36 approval 18 June 1976; subsequent approvals from Canadian Dept of Transport, German LBA and Australian Dept of Transport. First order (three), by Command Airways of Poughkeepsie, New York, 14 August 1974; deliveries began June 1976; first entered service, with Time Air, 24 August 1976.

VARIANTS: 330-200: Standard passenger version, as detailed.
330-UTT: Military utility tactical transport version. Described separately.
Sherpa: Freighter version of 330, with ramp type full width rear loading door. Described separately.

CUSTOMERS: Orders and options for 330, 330-UTT and Sherpa totalled 179 by start of 1991; Sherpa used by US Air Force as C-23A and US Army National Guard as C-23B (described separately); US Army also leases six ex-airline 330s for operation in Kwajalein area of Pacific, four of which modified to military standards by Field Aircraft Services of Calgary, Alberta.

DESIGN FEATURES: Derived from smaller STOL Skyvan, retaining latter's proven characteristics, including large square-section unpressurised cabin with low floor level, braced high-mounted wings, twin tail unit, and safe-life concept and design philosophy for structural components, conforms with CAB Pt 298 (US); meets FAR Pt 36 noise requirements by substantial margin.
First 26 Shorts 330s powered by 875 kW (1,173 shp) PT6A-45AS; next 40 given PT6A-45Bs; subsequent aircraft fitted with more powerful PT6A-45Rs and higher equipment standard, optional Goodrich pneumatic hoot de-icing on wing and tail leading-edges.
NACA 63A series (modified) wing sections; thickness/chord ratio 18 per cent at root, 14 per cent on outer panels, dihedral 3° on outer panels.
Following description applies to standard 330-200 passenger version.

FLYING CONTROLS: Single-slotted ailerons with geared trim tabs; twin unshielded horn aerodynamic balance rudders; full span elevator, aerodynamically balanced by set-back hinges; geared trim tabs in elevator and starboard rudder (port rudder, trim only); single-slotted three-section flaps; fixed incidence tailplane.

STRUCTURE: All-metal safe-life construction; wing centre-section (integral with top of centre-fuselage) tapered on leading- and trailing-edges, and is two-spar single-cell box with conventional skin and stringers; strut braced wing outer panels are reinforced Skyvan constant chord units, each with two-cell box and having smooth outer skin bonded to corrugated inner skin; fuselage in two main portions: nose portion (including flight deck, nosewheel bay and forward baggage compartment), centre (including main wing spar attachment frames and lower transverse beams carrying main landing gear and associated fairings), and rear portion (including aft baggage compartment and tail unit attachment frames); nose and rear fuselage of skin/stringer design, remainder smooth outer skin bonded to corrugated inner skin and stabilised by frames; two-spar twin-fin tail unit, with reinforced tailplane leading-edge.

LANDING GEAR: Menasco retractable tricycle type, with single wheel on each unit. Main units carried on short sponsons, into which the wheels retract hydraulically. Oleo-pneumatic shock absorbers. Nosewheel is steerable ±50°. Mainwheel tyre size 34 x 10.75-16; nosewheel tyre size 9-6. Normal tyre pressures: main units 5.45 bars (79 lb/sq in), nose unit 3.79 bars (55 lb/sq in).

POWER PLANT: Two 893 kW (1,198 shp) Pratt & Whitney Canada PT6A-45R turboprops, each driving a Hartzell five-blade constant-speed fully feathering metal low-speed propeller. Fuel tanks in wing centre-section/fuselage fairing; total usable capacity increased from original 2.182 litres (576 US gallons; 480 Imp gallons) to 2.546 litres (672.5 US gallons; 560 Imp gallons) in January 1985. Normal cross-feed provisions to allow for pump failure. Single pressure refuelling point in starboard landing gear fairing, backed by three gravity refuelling points in fuselage spine.

ACCOMMODATION: Crew of two on flight deck, plus cabin attendant. Dual controls standard. Standard seating for 30 passengers, in ten rows of three at 76 cm (30 in) pitch, with wide aisle. Seat rails fitted to facilitate changes in configuration. Galley, toilet and cabin attendant's seat at rear. Large overhead baggage lockers. Entire accommodation soundproofed and air-conditioned. Baggage compartments in nose and to rear of cabin, each with external access and capable of holding a combined total of 500 kg (1,100 lb) of baggage. Passenger door is at rear of cabin on port side. Passenger version has two emergency exits on the starboard side, two on the port side (including passenger door) and one in the flight deck roof. Mixed traffic version has full access to these emergency exits. For mixed passenger/freight operation a partition divides the cabin into a rear passenger area (typically for 18 persons) and a forward cargo compartment, the latter being loaded through a large port side door capable of admitting ATA 'D' type containers. In all-cargo configuration the cabin can accommodate up to seven 'D' type containers, with ample space around them for additional freight. Cabin floor is flat throughout its length, and is designed to support loadings of 181 kg (400 lb) per foot run at 610.3 kg/m² (125 lb/sq ft). Locally reinforced areas of higher strength are also provided. Seat rails can be used as cargo lashing points. Freight loading is facilitated by the low level cabin floor.

SYSTEMS: Hamilton Standard air-conditioning system, using engine bleed air. Hydraulic system of 207 bars (3,000 lb/sq in), supplied by engine driven pumps, operates landing gear, nosewheel steering, flaps and brakes (at half pressure) and includes emergency accumulators. Air/oil reservoir pressurised to 1.72 bars (25 lb/sq in) at 20°C. Main electrical system, for general services, is 28V DC and is of the split busbar type with cross-coupling for essential services. Lucas 28V 250A DC starter/generator for engine starting and aircraft services, with separate 1.5kW 200V AC output for windscreen anti-icing and demisting. Special AC sources of 115V and 26V available at 400Hz for certain instruments, avionics and fuel booster pumps. Anti-icing standard for engine intake ducts, inlet lips and propellers. Optional de-icing of wing and tailplane leading-edges.

AVIONICS: Wide range of radio and navigation equipment available to customer's requirements. Typical standard avionics comprise duplicated VHF communications and navigation systems, two glideslope/marker beacon receivers, two ILS repeaters, two radio magnetic indicators, one ADF, one transponder, one DME, PA system and weather radar. Flight data recorder and voice recorder available as standard options.

EQUIPMENT: Passenger safety equipment standard.