The L-39 Albatross succeeds the L-29 Maya/Delfin. The L-39 basic and advanced jet trainer first flew on 4 November, 1968. The aircraft is the standard jet trainer for former Warsaw Pact countries. It is designed for initial and advanced training. Several modified and upgraded versions have been developed since 1968, known as L-39C, L-39V, L-39ZA, L-39MS and L-39ZO. From 1971 to 1999 a total of 2921 units of L-39/59 family were delivered. A low-wing aircraft with tandem seating and a classic all-metal airframe, it is equipped with a three-point hydraulically operated retractable landing-gear. Trapezoidal wings have fuel tanks on their tips. The wing has double-slotted flaps with a takeoff deflection of 25° and landing deflection of 44°. The fuselage consists of two construction parts - the forward and the rear one. The rear fuselage and tail are removable. The electronic equipment and oxygen system are located in a dielectric nose cover. In L-39, the canopy of the cockpit is hinged to the right. In newer development types L-59 (originally L-39MS) and L-139 it is hinged hydraulically upwards to the rear. The power plant is an Al-25TL by-pass double-shaft turbojet engine with max. static thrust of 16.87 kN. The engine is started by a Saphire 5 single-shaft gas turbine. The types with maximum takeoff weight of 5,700 kg are equipped with a more powerful DV-2 engine with max. thrust of 21.57 kN. There is a classic mechanical control system with power transmission over levers and pull rods from both pilot posts. The electrical equipment is powered by the main generator (9 kW) from an accumulator enabling autonomous operation. The electrical net includes inverters (115 V and 3x36 V). Radio equipment of the aircraft consists of radio, communication, radionavigation and identification devices. For the training of landing and approach, a RSBN-5S close navigation system and ILS landing system are used. The aircraft is also equipped with the RKL-41 radio compass, RV-5 radio altimeter, MRP-56PS marker and an identification device. Specifications: Max. speed at 11,000 m-850 km/h; at 5,000 m-755 km/h; at sea level-720 km/h; Max. range (w\out auxiliary fuel)-1000 km; Max. range (with auxiliary fuel)-1750 km; Service ceiling-11 500 m; Max. climb (full load)-22 m/s; Flt. endurance (auxiliary fuel)-3 h 50 min; Flt. endurance (w\out auxiliary fuel)-2 h 30 min; Engine-AI-25TL Progress (Ivchenko); Thrust-16,87 kN; Max. takeoff weight-4700 kg; Empty weight-3540 kg; Wingspan (including fuel tanks)-9,46 m; Capacity of auxiliary fuel tanks-2x420 lit.; Length-12,13 m; Height-4,77 m; Wing area-18,8 m2; Max. permitted g- -4/+8g.