TYPE: Light fighter/advanced jet trainer.

PROGRAMME: Designed started late 1992; F124 turbofan selected as power plant mid-1994; Rockwell North American (now Boeing) awarded avionics contract late 1994. Development approved by Czech government 7 April 1995, followed by production commitment later the same month and 72-aircraft production contract 4 July 1997. Two prototypes (plus two airframes for static and dynamic test) built. First (two-seat) prototype/engine demonstrator (5831) rolled out 12 June and made first flight 2 August 1997.
Second (single-seat) prototype (5832), in Czech Air Force configuration (first flight 18 August 1998) named ALCA (Advanced Light Combat Aircraft); is first with full avionics and is avionics/weapons trials aircraft. Official first flight of 5832 was 20 August; public debut during Czech International Air Fest at Hradec Kralove 29 August 1998. Gun firing in Czech Republic followed by air-launched weapon trials in Norway in April and May 1999; nav/attack system trials August/September 1999. Weapons qualification tests at Cazaux, France, from May to July 2000.
First flight of production L159A (6001) 20 October 1999. Deliveries to CzAF due to have begun late 1999 (five aircraft, followed by 16 in 2000, 26 in 2001 and final 25 in 2002); however, first two (6006 and 6007) not delivered (to 4 Tactical Fighter Base at Caslav) until 29 December 2000, with first pilot conversion training beginning in mid-March 2001. Deliveries then rescheduled as 37 by end of 2001, 21 during 2002 and final 14 during first half of 2003. However, in May 2001, during which month aircraft evaluated by US Navy Test Pilot's School, Czech defence minister stated that CzAF will operate only 37 aircraft. Situation has taken many turns since then, and is still not clear; latest estimate (early 2003) was that between 24 and 36 aircraft would be offered for export.
The L159A fleet (then 25 aircraft) was grounded on 14 November 2001 following incidents to two aircraft apparently due to suspected avionics malfunctions. No other significant problems had been registered by the end of 2002, when co-production offer made to Polish industry.
First production L159B (6073) achieved maiden flight on 1 June 2002 and made international debut at Farnborough Air Show in following month; was due to complete 125 flight hours by end of that year.

CURRENT VERSIONS: L159A ALCA: Single-seater.
Detailed description applies to L159A except where indicated.
L159B: Tandem-seat trainer version, designed primarily for advanced and operational training; can also be configured to customer requirements from basic to lead-in fighter training, reconnaissance or ground attack. Further US$15 million invested by Boeing in July 2001 to develop software for this version.

CUSTOMERS: Czech Air Force order for 72 L159A valued at approximately US$1 billion. Production lots 1 and 2 comprised five and 10 aircraft respectively, of which 12 delivered by 31 March 2001. CzAF due to take delivery of L159A No.58 by end of 2002. Primary roles will be close air support, counter-insurgency, anti-ship missions, tactical reconnaissance, point air defence, air defence against slow/low-flying targets and border patrol. Initial order for L159B being negotiated with Czech MoD in late 2002. Prospect of exports to other East European and Baltic countries, including Poland, to whom a Maverick-armed version was offered in late 2000. Company said to be preparing offsets for sale to Slovak Air Force in July 2001, and to be negotiating with other 'very potential' customers. L159B being evaluated by Indian Air Force from May 2002 as possible (and cheaper) replacement for stalled order for BAE Systems Hawks. Greece also being targeted.

COSTS: L159B (baseline configuration) US$9.5 million (2002).

DESIGN FEATURES: Configuration generally as L-39/L-59 except for larger, redesigned nose to accommodate radar; longer fuselage; single-seat armoured cockpit; HOTAS controls; Western avionics; 297 kg (655 lb) additional fuel tank in lieu of second seat; permanent wingtip fuel tanks; seven external stores stations.
Wing section NACA 64A-012; sweepback 6o 30' on leading-edges; dihedral 2o 30'; incidence 2o; twist 0o.

FLYING CONTROLS: Conventional primary surfaces; ailerons and elevators actuated hydraulically, rudder mechanically with electrically operated trim tab. Artificial feel standard. Twin underfuselage airbrakes and double-slotted trailing-edge flaps, also actuated hydraulically. Maximum flap deflection 44o.

STRUCTURE: Based on that of L-59, but substantially modified. Approximately 200 Czech subcontractors involved in programme.

LANDING GEAR: Hydraulically retractable tricycle type, with single wheel and oleo-pneumatic shock-absorber on each unit. Main units retract inward into wings, nosewheel forward. Moravan K36 wheels and 610x215 tyres (pressure 6.00 to 8.00 bar; 87 to 116 lb/sq in) on main units; nose unit has Moravan K37 wheel and 460x180 tyre (pressure 3.52 to 4.48 bar; 51 to 65 lb/sq in). Moravan K52 air-cooled hydraulic brakes with anti-skid system. Nose unit hydraulically steerable ±59o. Minimum ground turning radius 5.70 m (18 ft 8½ in).

POWER PLANT: One 28.2 kN (6,330 lb st) Honeywell/TTEC F124-GA-100 turbofan with dual-redundant FADEC. Internal fuel of L159A (total capacity 1,980 litres; 523 US gallons; 436 Imp gallons) is contained in six fuselage and two wingtip tanks and protected by OBIGGS (onboard inert gas generation system); L159B omits one 350 litre (92.5 US gallon; 77.0 Imp gallon) fuselage tank, internal capacity thus 1,630 litres (431 US gallons; 359 Imp gallons) and does not have OBIGGS. Up to four external tanks can be carried underwing: two 500 litre (132 US gallon; 110 Imp gallon) tanks on inboard stations, two 350 litre (92.5 US gallon; 77.0 Imp gallon) tanks on inboard or centre stations. Pressure fuelling point in port side of lower front fuselage; gravity points in upper fuselage aft of canopy and in each wingtip tank. In-flight refuelling capability began flight testing on L159B in August 2002.

ACCOMMODATION: Single VS-2C ejection seat in armoured cockpit (L159A); two VS-2B seats and no armour in L159B. Canopy opens sideways manually in L159A, upwards hydraulically in L159B.

SYSTEMS: PBS simple cycle environmental control system, using engine bleed air; Honeywell cockpit pressure control system (maximum differential 0.28 bar; 4.1 lb/sq in). Dual hydraulic systems, each at pressure of 210 bar (3,045 lb/sq in), actuating ailerons, elevators, flaps, airbrakes, landing gear, wheel brakes and nosewheel steering. System maximum flow rate 35 litres (9.25 US gallons; 7.7 Imp gallons)/min. Hydraulic tank pressurised by nitrogen at 2.50 bar (36.3 lb/sq in). Pneumatic system (1.80 bar; 26.1 lb/sq in) for canopy sealing.
Hamilton Sundstrand 40kVA integrated drive generator provides 200/115 V three-phase main AC power at 400 Hz; 28 V DC power from 6 kW VUES LUN-2134 back-up generator and Varta/Aero 25 Ah battery. Intertechnique OBOGS oxygen system. Windscreen and air intakes de-iced by engine bleed air. PBS Safir 5F APU, operable up to 9,000 m (29,520 ft) altitude, for engine starting and emergency hydraulic or electrical power.

AVIONICS: Integration of complete avionics suite by Boeing.
Comms: Two Rockwell Collins ARC-210 UHF/VHF radios; Honeywell AN/APX-100 IFF.
Radar: Galileo Grifo L multimode pulse Doppler radar (L159A only).
Flight: Bendix/King KNR 634A VOR/glideslope/MKR, KDM 706A DME and air data computer; Honeywell H-746G ring laser gyro INS with embedded GPS.
Instrumentation: Flight Visions FV-3000 HUD; dual Honeywell 102 x 102 mm (4 x 4 in) liquid crystal colour head-down MFDs; Astronautics mechanical ADI and HSI. Optional helmet-mounted display/sight and NVG-compatible lighting.
Mission: Dual Flight Visions 6400-100 mission computers with HUD symbology generator; provision for reconnaissance and jamming pod. Hamilton Sundstrand weapon delivery system. Dynamic Control Corporation stores management system.
Self-defence: BAE Systems Sky Guardian 200 RWR; Thales (Vinten) Vicon 78 Series 455 countermeasures dispenser.

ARMAMENT: No built-in armament. Seven external storesstations: one under fuselage and three under each wing. Fuselage station stressed for 300 kg (661 lb) load; inboard, centre and outboard wing pylons stressed for 550, 320 and 150 kg (1,213, 705 and 331 lb) each repectively (L159B centre pylons 500 kg; 1,102 lb only). Primary armament comprises AIM-9 Sidewinder AAMs, AGM-65 Maverick ASMs, and SUU-20 or CRV7 unguided rocket pods. Has also been trialled with Brimstone missile and TIALD targeting pod.