The L-139 aircraft, which was developed from the L-39ZA, is powered by an Allied Signal TFE-731.4 turbofan engine. Similarly to the L-59, it has got Bendix-King/Flight Visions avionics including HUD, a modern WDNS of US provenance, OBOGS, fatigue monitoring system, VS-2A zero/zero ejection seats, armament system corresponding to NATO standards, etc.