PROGRAMME: First flight (X01/OK-130) 28 December 1988; five development aircraft (X02/OK-WZA, X03/OK-024, X05/OK-134, OK-XZA and OK-136), plus one for static test (X04) and one demonstrator (OK-CZD). Two versions originally planned: L 610 M with 1,358 kW (1,822 shp) Walter M602 turboprops and L 610 G with General Electric CT7s; contract 18 January 1991 for General Electric to provide CT7-9Ds for L 610 G (first two delivered shortly afterward); first flight of this version (OK-XZA) 18 December 1992. Programme for L 610 M abandoned 1996. In November 1999, Swiss marketing agency Airlines Partners SA sold two aircraft to Burundi, using marketing name Ayres 7000. Certification to FAR Pt 25 was then expected about nine months after contract signature by first US customer, but not achieved by mid-2003. Twelve production aircraft were in various stages of completion by June 2000, but Let and Ayres bankruptcies later that year followed by entire L 610 programme (including putative L 610 M) being offered for sale in March 2001. Aircraft was not included in July 2001 sale of Let to Moravan Aeroplanes, but L 610 G added to LZ portfolio in early 2002.
CURRENT VERSIONS: L 610 G: General Electric CT7-9D turboprops, four-blade propellers and Rockwell Collins digital including EFIS, weather radar and autopilot. First prototype used for Czech and US certification testing; second prototype (OK-CZD) completed and was exhibited at Farnborough Air Show in September 1998; third (first series production) aircraft under construction at that time.
Ayres 7000: Described by Ayres as 'face-lift' upgrade of L 610 G; also projected in freighter (7000F) and military (7000M) versions: with different details from current version. No production.
CUSTOMERS: Seven, including two prototype L 610 Gs, flown by mid-2000. Options for 30 from several (unidentified) operators, but no deliveries by early 2003.
COSTS: US$9,5 million (2002).
DESIGN FEATURES: Intended to meet FAR Pt 25 requirements; high wing for propeller ground clearance and pannier-mounted landing gear to reduce mainwheel leg length and simplify loading/unloading; high-mounted tailplane for optimum control authority.
Wing sections MS(1)-0318 at root, MS(1)-0312 at tip; thickness/chord ratios 18.29 (root) and 12 per cent (tip); dihedral 2°; incidence 3° 8' 38" at root, 0° at tip; quarter-chord sweepback 1°.
FLYING CONTROLS: Conventional and manual. Ailerons are horn balanced. Rudder trim tab and both aileron trim tabs actuated by electromechanical strut. Elevator trim tabs actuated mechanically by screw-nut mechanism. Automatic spring tab in rudder. Electrohydraulically actuated single-slotted Fowler flaps. Ground spoilers. Lateral control spoilers deflected proportionately to aileron deflection. Electrically actuated gust lock.
STRUCTURE: All-metal, fail-safe stressed skin structure; circular-section fuselage between flight deck and tail; wing contains high-grade aluminium and high-strength steel; honeycomb spoiler panels.
LANDING GEAR: Retractable tricycle type, with single wheel on each unit. Hydraulic actuation, mainwheels retracting inward to lie flat, without doors, in fairing each side of fuselage; nosewheel retracts forward. Oleo-pneumatic shock-absorber in each unit. Mainwheels are type K 34-3100-7, with 15.00-16 (16 ply) or 1050x390-480 tubeless tyres; type K 35-1100-7 nosewheel has a 720x310-10 or 29x11.00-10 (10 ply) tubeless tyre. Hydraulic disc brakes and electronically controlled anti-skid units. Minimum ground turning radius 18.33 m (60 ft 1¾ in) about wingtip, 7.83 m (25 ft 8¼ in) about nosewheel.
POWER PLANT: Two 1,305 kW (1,750 shp) General Electric CT7-9D turboprops, each driving a Hamilton Sundstrand HS-14RF-23 four-blade fully feathering metal propeller with reversible pitch. Fuel in two integral wing tanks, combined usable capacity 3,420 litres (903.5 US gallons; 752 Imp gallons). Pressure refuelling point in fuselage, gravity points in wings. Oil capacity 30 litres (7.9 US gallons; 6.6 Imp gallons).
ACCOMMODATION: Crew of two on flight deck, plus one cabin attendant. Standard accommodation for 40 passengers, four-abreast at seat pitch of 76 cm (30 in). Galley, two wardrobes, lavatory, freight and baggage compartment, all located at rear of cabin. Alternative mixed (passenger/cargo) and all-cargo layouts available; latter can accommodate five 1.63 x 2.08 x 1.57 m (64 x 82 x 62 in) containers or pallets in main cabin plus a further 200 kg (441 lb) in aft bulk cargo area at rear of main cargo hold. Military version has capacity for 30 fully equipped troops, 30 paratroops plus jumpmaster, 19 stretchers or five critically ill patients plus medical attendants, or up to 5,000 kg (11,023 lb) of cargo plus a loadmaster.
Passenger door at rear of fuselage, cargo door at front, both opening outward on port side. Inward-opening service door on starboard side, opposite passenger door, serving also as emergency exit; inward-opening emergency exit beneath wing on each side. Paratroop version has inward-opening/sliding door aft of wing on port side. Entire accommodation pressurised and air conditioned.
SYSTEMS: Dual Hamilton Sundstrand R 79-3W air conditioning systems using engine bleed air. Nord Micro digital, fully automatic pressurisation system gives 0.36 bar (5.2 lb/sq in) differential at flight level of 7,200 m (23,625 ft) and a cabin altitude of 2,400 m (7,875 ft). Duplicated hydraulic systems (one main and one standby), operating at pressure of 210 bar (3,045 lb/sq in). Optional 20 kW Safir 5 K/G APU in tailcone, for engine starting and auxiliary on-ground and in-flight power.
Electrical system supplied by two 28 V 400 A air-cooled, brush-type engine-driven starter/generators and two 37 or 43 Ah Ni/Cd batteries for ground and emergency operation. Starter/generators are connected to two main bushbars; distribution busses supplied via circuit breakers. Brushless, air-cooled 26 kVA frequency-wild alternator on each engine, for heating and de-icing engine intakes, propellers and windscreen, and serving also as emergency power supply for 28 V DC via transformer/rectifier unit. External power receptacle for DC standard; optional for AC. APU (alternator for on-ground AC power) also optional. Two inverters for 26/115 V AC at 400 Hz. One 2.5 Ah EPU supplies flight instruments in event of malfunction of AC or DC generators, batteries or TRU. Gumotex Breclav or Goodrich pneumatic de-icing boots on wing and tail unit leading-edges; ACT electric anti-icing system for engine inlets; electric de-icing of propeller blade roots, windscreen, pilot static system and horn balances. Oxygen system for crew and four passengers.
AVIONICS: Rockwell Collins Pro Line II suite and EFIS-86 standard.
Comms: Dual 760-channel VHF; single HF (optional); ATC transponder; intercom/PA system; cockpit voice recorder.
Radar: WXR-350 weather radar.
Flight: APS-65 autopilot; AHS-85 AHRS; dual ILS with two LOC/glideslope receivers and two marker beacon receivers; single or dual ADF; dual compasses; single or dual radio altimeters; navigation computer; flight data recorder; Cat. II approach aids.
Instrumentation: Five-tube EFIS-86 with EADI and HSI for each crew member and central MFD; weather radar data can be displayed on HSI and/or MFD.