ATR 42

TYPE: Twin-turboprop airliner.

PROGRAMME: Joint launch by Aerospatiale (now in EADS) and Aeritalia (now Alenia) in November 1981, following June 1981 selection of P&WC PW120 turboprop as basic power plant; first flights of two prototypes 16 August 1984 (F-WEGA) and 31 October 1984 (F-WEGB); first flight production aircraft 30 April 1985; simultaneous certification to JAR 25 by France and Italy 24 September 1985, followed by USA (FAR Pt 25) 25 October 1985, Germany 12 February 1988, UK 31 October 1989; deliveries began 3 December 1985 to Air Littoral.
Series 500, with 'new look' interior, announced at Paris Air Show 14 June 1993; first flight F-WWEZ (c/n 443) 16 September 1994; French and UK certification 28 July 1995; first delivery (F-OHFF to Air Dolomiti) 31 October 1995. FAA certification 13 May 1996.

CURRENT VERSIONS: ATR 42-300: Initial version; phased out of production in 1996. Two Pratt & Whitney Canada PW120 turboprops, each flat rated at 1,342 kW (1,800 shp) for normal operation and 1,492 kW (2,000 shp) OEI; Hamilton Sundstrand 14SF four-blade constant-speed fully feathering and reversible-pitch propellers.
ATR 42-320: Identical to 42-300 except for optional PW121 engines for improved hot/high performance; OWE increased/payload decreased by 5 kg (11 lb). Phased out in 1996.
ATR 42-400: P&WC PW121A engines with six-blade Hamilton Sundstrand 568F propellers; maximum cruising speed 266 kt (493 km/h; 306 mph); maximum range 825 n miles (1,527 km; 949 miles) with full payload. First flight 12 July 1995 (F-WWEF/OK-AFE); two Srs 420s ordered for CSA, and both delivered 14 March 1996, having received DGAC certification on 27 February. No further civil aircraft.
ATR 42-500: Principal ATR 42 version from 1996. Compared with Series 300, has more powerful engines, reinforced wings to allow greatly increased cruising speed and higher weights; all systems improvements of ATR 72, including flight management computers; cockpit, elevators and fin from ATR 72-100; strengthened landing gear; electrically operated main doors; reinforced fuselage and wing centre-section.
Description applies to ATR 42-500, except where indicated.
ATR 42 Tube (formerly Cargo QC): Quick-change (1 hour) interior to hold nine containers. Available as new-build or retrofit. Conversion programme includes installation of 2.95 x 1.80 m (9 ft 8 in x 5 ft 11 in) cargo door and modification of cabin into an E-class cargo compartment with strengthening of floor to 400 kg/m2 (82 lb/sq ft); total volume for cargo transport 56 m3 (1,978 cu ft); maximum payload 5,883 kg (12,970 lb); parallel cabin section 10.25 m (33 ft 7½ in) long, tapered section 4.47 m (14 ft 8 in) long, with positions for up to four spider nets. MTOW in this configuration 16,900 kg (37,528 lb), MLW 16,400 kg (36,156 lb), MZFW 15,540 kg (34,260 lb). Launch customer, DHL Aviation of South Africa, received first of two converted -300s in October 2000.
ATR 42 Large Cargo Door: As ATR 42 Tube, but with 2.79 x 2.95 m (9 ft 2 in x 9 ft 8 in) upward-opening cargo door in port front fuselage aft of cockpit to permit loading of four pallets or five LD3 containers. Weights as ATR 42 Tube. Conversions by Aeronavali in Italy; first retrofit (for Farnair Europe) was due late 2001.
ATR 42F: Military/paramilitary freighter with modified interior, reinforced cabin floor, port-side cargo/airdrop door can be opened in flight; can carry 3,800 kg (8,377 lb) of cargo of 42 passengers over 1,250 n miles (2,315 km; 1,438 miles). One delivered to Gabon 1989.
ATR Calibration: Projected navaid calibration version.
ATR 42L: Projected freighter with lateral cargo door; available as ATR 42 Large Cargo Door (see above).
ATR 42 Surveyor: Maritime and rescue version; described separately.

CUSTOMERS: Total 376 firm orders, of which 369 delivered, by mid-June 2003. Four ordered and 10 delivered in 1998; 14 ordered and 12 delivered in 1999; six (plus four options) sold in 2000; five (all -500s) delivered in 2001 and five in 2002.

COSTS: ATR 42-500 development cost US$50 million; unit price US$13.8 million (2000).

DESIGN FEATURES: Designed to JAR 25/FAR Pt 25; high wing of medium sapect ratio, with constant-chord centre section and tapered outer panels; T-type tail with tapered tailplane and sweptback fin and fillet; pannier-mounted main landing gear.
Wing section Aerospatiale RA-XXX-43 (NACA 43 series derivative); thickness/chord ratio 18 per cent at root, 13 per cent at tip; constant-chord, no-dihedral centre-section with 2o incidence at root; outer panels 3o 6' sweepback at quarter-chord and 2o 30' dihedral.

FLYING CONTROLS: Conventional and manual. Lateral control assisted by single spoiler surface ahead of each outer flap; each aileron has electrically actuated trim tab; fixed incidence tailplane; horn-balanced rudder and elevators, each with electrically actuated trim tab; two-segment double-slotted flaps on offset hinges with Ratier-Figeac hydraulic actuators.

STRUCTURE: Two-spar fail-safe wings, mainly of aluminium alloy, with leading-edges of Kevlar/Nomex sandwich; wing top skin panels aft of rear spar are of Kevlar/Nomex with carbon reinforcement; flaps and ailerons have aluminium ribs and spars, with skins of carbon fibre/Nomex and carbon/epoxy respectively; fuselage is fail-safe stressed skin, mainly of light alloy except for Kevlar/Nomex sandwich nosecone, tailcone, wing/body fairings, nosewheel doors and main landing gear fairings; fin (attached to rearmost fuselage frame) and tailplane carbon structure; CFRP/Nomex sandwich rudder and elevators; dorsal fin of Kevlar/Nomex and GFRP/Nomex sandwich; engine cowlings of CFRP/Nomex and Kevlar/Nomex sandwich, reinforced with CFRP in nose and underside; propeller blades have metal spars and GFRP/polyurethane skins.
EADS France originally responsible for design and construction of wings and engine nacelles, flight deck and cabin layout, installation of power plant, flying controls, electrical and de-icing systems, and final assembly and flight testing of civil passenger versions; wing manufacture and testing reallocated to EADS Sogerma at Bordeaux from late 2001. Alenia Aeronautica builds fuselage and tail unit, installs landing gear, hydraulic system, air conditioning and pressurisation systems. ATR 42/72 manufactured at St Nazaire and Nantes (France), Pomigliano d'Arco and Capodichino (Italy), and assembled in Toulouse.

LANDING GEAR: Hydraulically retractable tricycle type, of Messier-Dowty trailing-arm design, with twin wheels and oleo-pneumatic shock-absorber on each unit. Nose unit retracts forward, main units inward into fuselage and large underfuselage fairing. Goodrich wheels and multiple-disc mainwheel brakes and Hydro-Aire anti-skid units. Mainwheel tubeless tyres, size 32x8.8R16 (10/12 ply), pressure 8.69 bar (126 lb/sq in) or H34x10.0R16 (14 ply). Nosewheel tubeless tyres, size 450x190-5 (10 ply), pressure 4.34 bar (63 lb/sq in) or 450x190R5 (10 ply). Minimum ground turning radius 17.37 m (57 ft 0 in).

POWER PLANT: Two 1,790 kW (2,400 shp) Pratt & Whitney Canada PW127E turboprops; ATR 72-210 nacelles; six-blade Ratier-Figeac/Hamilton Sundstrand 568F propellers with new electronic control giving faster response and better synchrophasing (as for ATR 72-500 from 1996). Propeller brake on starboard engine to enable engine to be used as auxiliary power unit for internal air conditioning.
Fuel in two integral tanks in spar box, total capacity 5,736 litres (1,515 US gallons; 1,262 Imp gallons). Single pressure refuelling point in starboard wing leading-edge. Gravity refuelling points in wing upper surface. Oil capacity 40 litres (10.6 US gallons; 8.8 Imp gallons).

ACCOMMODATION: Crew of two on flight deck; folding seat for observer. Seating for 42 passengers at 84 cm (33 in) pitch; or 46, 48 (standard) or 50 passengers at 76 cm (30 in) pitch; compared with Series 300, ATR 42-500 has completely new interior with new ceiling and sidewalls, indirect lighting, more sound damping; call buttons and reading lights relocated; overhead bins lengthened to 2 m (6 ft 6¾ in) accommodate skis, golf clubs and fishing equipment carried as hand baggage. Baggage volume increased by 40 per cent. Active noise control system, previously offered as an option, is no longer available. ATR 42-500s have structural acoustic treatment comprising reinforcement of seven fuselage frames adjacent propeller plane; dynamic vibration absorbers in this area; and internal aluminium skin damping material forward and aft of wing.
Passenger door, with integral steps, at rear of cabin on port side. Front baggage/cargo compartment between flight deck and passenger cabin, with access from inside cabin and separate loading door on port side; lavatory, galley, wardrobe and seat for cabin attendant at rear of passenger cabin, with service door on starboard side; rear baggage/cargo compartment aft of passenger cabin; additional baggage space provided by overhead bins and underseat stowage. Entire accommodation, including flight deck and baggage/cargo compartments, pressurised and air conditioned. Emergency exit via rear passenger and service doors, and by window exits on each side at front of cabin.

SYSTEMS: Improved in parallel with development of ATR 72; following refers to baseline aircraft. Honeywell air conditioning and Softair pressurisation systems, utilising engine bleed air. Pressurisation system (nominal differential 0.41 bar; 6.0 lb/sq in) provides cabin altitude of 2,040 m (7,000 ft) at flight altitudes of up to 7,620 m (25,000 ft).
Two independent hydraulic systems, each at pressure of 207 bar (3,000 lb/sq in), driven by electrically operated Abex pump and separated by interconnecting valve controlled from flight deck; system flow rate 7.9 litres (2.09 US gallons; 1.74 Imp gallons)/min; one system actuates wing flaps, spoilers, propeller brake, emergency wheel braking and nosewheel steering; second system for landing gear and normal braking. Kleber-Colombes pneumatic system for de-icing of wing leading-edges, tailplane leading-edges and engine air intakes; noses of aileron and elevator horns have full-time electric anti-icing.
Main electrical system is 28 V DC, supplied by two Auxilec 12 kW engine-driven starter/generators and two Ni/Cd batteries (43 Ah and 15 Ah), with two solid-state static inverters for 115/26 V single-phase AC supply; 115/200 V three-phase supply from two 20 kVA frequency-wild engine-driven alternators for anti-icing of windscreen, flight deck side windows, stall warning and airspeed indicator pitots, propeller blades and control surface horns. Eros/Puritan oxygen system. Instead of APU, starboard propeller braked and engine run to give DC and 400 Hz power, air conditioning and hydraulic pressure.

AVIONICS: Rockwell Collins com/nav equipment. Improved in parallel with development of ATR 72; following refers to baseline aircraft.
Comms: CVR, PA system.
Radar: Honeywell P-660 weather radar.
Flight: Honeywell DFZ 600 AFCS; AZ-800 ADCs; AH 600 AHRS with avionics standard communication bus; Hamilton Sundstrand GPWS; L-3 digital FDR; Rockwell Collins DME; Honeywell FMZ-800 flight management system and dual GPS receivers installed in four Continental Airlines ATR 42s to allow autonomous approaches.
Instrumentation: EZ-820 electronic flight instrument system.


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