Aero L-39 Albatros


The Aero L-39 Albatros is a high-performance jet trainer developed in Czechoslovakia by Aero Vodochody. It was designed during the 1960s as a replacement for the Aero L-29 Delfín as a principal training aircraft. It was the first trainer aircraft to be equipped with a turbofan powerplant. The type was exported to a wide range of countries as a military trainer.
The L-39 Albatros later served as the basis for the updated L-59 Super Albatros, as well as the L-139. A further development of the design, designated as the L-159 ALCA, entered production in 1997. To date, more than 2,800 L-39s have served with over 30 air forces around the world. The Albatros is the most widely used jet trainer in the world; in addition to performing basic and advanced pilot training, it has also flown combat missions in a light-attack role. The design never received a NATO reporting name.
At the Farnborough Airshow in July 2014, Aero Vodochody announced the launch of the L-39NG, an upgraded and modernised version of the L-39.

Development

In 1964, Czechoslovak aircraft manufacturer Aero Vodochody embarked on a new design project to meet the specified requirements for a "C-39", setting up a design team under the leadership of Jan Vlček. This aircraft was to serve as a replacement for the Aero L-29 Delfín, an early jet-powered trainer, as a principal training aircraft. Vlcek envisioned the type, a twin-seat single-engine aircraft, being adopted as the primary trainer throughout the Warsaw Pact nations.
On 4 November 1969, the L-39 conducted its maiden flight, for which it was piloted by Rudolf Duchoň, the factory's test pilot. Serial production of the initial model of the L-39, designated L-39C, commenced in 1971. In 1972, the L-39 Albatros was formally recognized by the majority of the countries comprising the Warsaw Pact as their preferred primary trainer, after which point, sizable orders from military customers throughout the bloc proceeded, many of which were from the Soviet Air Forces. In 1974, the first L-39 trainer entered service with the Czechoslovak Air Force.
Several specialised variants of the base L-39 design were quickly introduced. In 1972, a purpose-built target tug variant, the L-39V, conducted its initial flight. In 1975, the first L-39ZO training/light combat model, which was equipped with four underwing hardpoints as well as a strengthened wing and modified landing gear, performed its first flight. In 1977, the first L-39ZA light combat variant, which was fitted with a single Gryazev-Shipunov GSh-23 cannon mounted underneath the fuselage in addition to the four hardpoints and strengthening of the L-39ZO, made its maiden flight.
According to aerospace publication Flight International, roughly 200 L-39s were being sold each year upon the jet trainer market during the late 1980s. According to the Stockholm International Peace Research Institute, in 1993, the total export orders gained for the L-39 represented 80 per cent of the value of all Czech military product export sales made for that year. During the 1990s, shortly following the dissolution of the Soviet Union and the end of the Cold War, Aero Vodochody decided to develop versions of the Albatros equipped with Western-sourced avionics, engines, and weapon systems. Around the same time, Aero Vodochody formed an active partnership with Elbit Systems of Israel, under which a number of L-39s were delivered to Elbit to be equipped with modern electronics and onboard systems before being re-exported to end users such as the Royal Thai Air Force.
Sales of the L-39 declined during the 1990s. This downturn has been attributed to the loss of the captive Warsaw Pact trainer market, to which a substantial proportion of the total aircraft manufactured had been historically sold to; allegations about Czechoslovak banks being unable to finance the defense industry and inaction on the part of the Czechoslovak government; and concerns over the quality of manufacturing standards. In 1996, production of the L-39 came to an end. Since the end of production, Aero Vodochody has developed several improved variants of the L-39 to take its place, and has continued extensive support and overhaul operations for existing L-39 customers.
One of the replacements for the L-39 Albatros was the Aero L-159 Alca, a modernised version of the L-39. Originally, Aero Vodochody had intended to develop the L-159 in partnership with Elbit, but the Czech Ministry of Defense instead selected Rockwell Collins to partner on the program. The limited success of the L-159 led Aero to announce at the 2014 Farnborough Airshow that it was developing an upgraded version of the L-39, designated L-39NG, to compete with the Alenia Aermacchi M-346 and British Aerospace Hawk. The L-39NG replaces the AI-25 turbofan with a Williams FJ44 engine; the airframe is modified, the wingtip fuel tanks being eliminated, and a new suite of avionics will be provided. First flight of the L-39NG was in September 2015, with deliveries starting in 2020.

Design

The L-39 Albatros was designed to be a cost-effective jet-powered trainer aircraft, which is also capable of performing ground attack missions. For operational flexibility, simplicity, and affordability, the majority of onboard systems have been simplified to avoid incurring high levels of maintenance, as well as to minimize damage caused by mishandling when flown by inexperienced air crew. It could be readily flown from austere airstrips such as frozen lakebeds, enabled through the rugged design of the landing gear and favourable low landing speeds. The aircraft's flying qualities are reportedly simple, which is made easier by way of a rapid throttle response, making it easier for students who had never previously flown a jet aircraft before to successfully control. As a training platform, the L-39 itself comprised part of a comprehensive system which also used flight simulators and mobile ground test equipment.
The low-set, straight wing has a double-taper planform, 2½-deg dihedral from the roots, a relatively low aspect ratio, and fuel tanks permanently attached to the wingtips. The trailing edge has double-slotted trailing edge flaps inboard of mass-balanced ailerons; the flaps are separated from the ailerons by small wing fences. An automatic trimming system was present, the flaps and the trim system being connected in order to counteract the potentially large pitch changes that would otherwise be generated by vigorous movements of the flaps. The tall, swept vertical tail has an inset rudder. Variable-incidence horizontal stabilizers with inset elevators are mounted at the base of the rudder and over the exhaust nozzle. Side-by-side airbrakes are located under the fuselage ahead of the wing's leading edge. The flaps, landing gear, wheel brakes and air brakes are powered by a hydraulic system. Controls are pushrod-actuated and have electrically powered servo tabs on the ailerons and rudder. Operational g-force limits at are +8/-4 g.
A long, pointed nose leads back to the tandem cockpit, in which the student and instructor sit on Czech-built VS-1 ejection seats under individual canopies, which are opened manually and are hinged on the right. The rear seat, typically used by the instructor, is elevated slightly to readily enable observation and guidance of the student's actions in the forward position. The design of the cockpit, panel layout and many of its fittings resemble or are identical in function to those of other commonly-used Soviet aircraft; for example, the procedure for deploying the ejection seat is exactly the same as for the Mikoyan MiG-29. The cockpit is highly pressurized, requiring the air crew to wear oxygen masks only when flying in excess of 23,000 feet. A gyro gunsight for weapon-aiming purposes is typically present in the forward position only.
A single turbofan engine, an Ivchenko AI-25TL is positioned in the rear fuselage, fed through shoulder-mounted, semi-circular air intakes just behind the cockpit and the tailpipe below the horizontal tailplane. The engine has a time between overhaul of 1,000 flight hours; however, it is allegedly cheaper than the majority of turbine engines to overhaul. Five rubber bag fuel tanks are located in the fuselage behind the cockpit. Several heavy radio units are typically installed in an aft avionics bay; these are often removed on civilian-operated aircraft and replaced with a 70-gallon fuel tank. Additional fuel tanks can be fitted in the rear cockpit position and externally underneath the wings; the tip-tanks can also be expanded for a greater fuel capacity.
The aircraft is fitted with a hydraulically-actuated retractable nosewheel undercarriage which is designed to allow operation from grass airfields. The main landing gear legs retract inward into wing bays while the nose gear retracts forward. The basic L-39C trainer has provision for two underwing pylons for drop tanks or practice weapons, but these are not usually fitted. It can be armed with a pair of K-13 missiles to provide a basic air defense capability. Light-attack variants have four underwing hardpoints for ground attack stores, while the ZA variant also has an underfuselage gun pod. Mock UB-16 rocket pods can also be installed for visual appearance only.

Operational history

Abkhazia

In the spring of 2008, a number of Georgian drones were shot down by Abkhazian separatist forces over the Abkhazia region. The Abkhazian separatist forces claimed that one of its missile-equipped L-39s had shot down a Georgian Hermes 450 unmanned reconnaissance drone.

Afghanistan

The Taliban Air Force had managed to obtain around five L-39C aircraft from the remnants of the former Democratic Republic of Afghanistan Air Force; with foreign technical support and pilots, these were placed into combat operations during the later stages of the 1996-2001 phase of the Afghan civil war against the Northern Alliance. In early 2001, only two of these reportedly remained operational. Following the United States invasion of Afghanistan in 2001, a number of L-39s were inducted into the Afghan Air Force.

Azerbaijan

A quantity of L-39s, along with older L-29s, were used extensively by Azeri forces to perform ground attack missions during the Nagorno-Karabakh War in the 1980s and early 1990s. A number of these were reportedly shot down by air defenses employed by the Nagorno-Karabakh Defense Army. In September 2015, Aero Vodochody sought a large order for the latest model of the L-39 to Azerbaijan; by this point, Azerbaijan had a total of 24 airworthy L-39s remaining in service.

Chechnya

The newly de facto independent Chechen Republic of Ichkeria found itself with dozens of L-39s left at Khankala and Kalinovskaya airbases by the Soviet Air Force in 1992. Most of these, however, were reportedly abandoned or not in flyable condition, but during the August–November 1994 conflict between nationalist and pro-Russian forces L-39s were deployed and were possibly one of the few air attack elements on Dzhokar Dudayev's forces. At least one was reported as shot-down near Goragorsk on October 4 by a Strela-2 MANPADS fired by Doku Zavgayev's pro-Russian militia. The pilot, Col. Ali Musayev and the co-pilot Dedal Dadayev were killed.
One of the main reasons that prompted the first Su-25 air raids that destroyed the Chechen air force on the ground, and started the Russian intervention, were preparations being performed by Dudayev's air force, which had been spotted by reconnaissance Sukhoi Su-24MRs. There were fears that these aircraft could slow or deter the Russian air and ground campaign, as well as the capability of several aircraft to conduct kamikaze attacks on Russian nuclear power plants.

Iraq

Iraq became the first export customer for the L-39 Albatros. By mid 1970, the Iraqi Air Force had procured a considerable number of L-39 trainers, having transferred the bulk of their training activities onto the Czechoslovak aircraft. During the American-led invasion of Iraq in 2003, on 14 April 2003, a pair of United States Navy McDonnell Douglas F/A-18 Hornets attacked several L-29 and L-39 aircraft on the ground at an airfield near the city of Tikrit; these had been believed to have been modified to perform as delivery platforms for weapons.

Libya

Libya acquired some 180 L-39ZOs around 1978 which served at Sabha and Okba Ben Nafi flying schools along with Yugoslav-made G-2 Galeb for advanced jet training and Italian-made SF.260s.
The L-39s were deployed during the Chadian-Libyan conflict, mainly to Ouadi Doum air base. During the final Chadian offensive in March 1987, the Chadians captured Ouadi Doum along with several aircraft and Soviet SAM systems and tanks. A Chadian report to the UN, reported the aforementioned capture on 11 L-39s and the destruction of at least four of them.
In the midst of that conflict, on April 21, 1983, three LARAF Ilyushin Il-76TDs and one Lockheed C-130 Hercules landed at Manaus Airport, Brazil after one of the Il-76s developed technical problems while crossing the Atlantic Ocean. The aircraft were then searched by the Brazilian authorities: instead of medical supplies – as quoted in the transport documentation – the crate of the first of 17 L-39s bound for Nicaragua together with arms and parachutes, to support the country's war against US-backed Contras, were found. The cargo was impounded for some time before being returned to Libya, while the transports were permitted to return to their country. During the 1990s and 2000s, Libya made multiple attempts to get components and services for its air force in spite of an embargo placed upon the country by United Nations Security Council Resolution 748; by 2001, only half of Libya's L-39s were serviceable as a consequence.

Russia

Following the dissolution of the Soviet Union and the formation of the Russian Air Force in 1991, the newly formed service found itself with hundreds of L-39 aircraft, the majority of which were surplus to their training requirements. According to author Stephan Wilkinson, by 2005, Russia was seeking to potentially sell up to 800 of their L-39s, which were receiving only a basic level of maintenance once per month while their fate was being decided. Starting in the early 1990s, the Russian Air Force has pursued the development of a domestically-built jet trainer, for which the Yakovlev Yak-130 was selected; the Yak-130 shall eventually replace the L-39 in Russian service within its operational roles.

Syria

The Syrian Arab Air Force has operated a number of armed L-39ZA light attack variants. Since the early stages of the Syrian civil war, the Syrian Air Force's L-39 aircraft have been routinely deployed in counter-insurgency operations against various rebel ground forces, a number of these aircraft have also been shot down by ground fire. They were first used operationally during the Battle of Aleppo, launching several strikes upon rebel-held positions. It has been claimed the L-39 was the first fixed-wing aircraft to be employed against the rebels.
In February 2013, insurgents successfully captured a number of intact L-39s, along with their support equipment, after raiding and later taking over the Al-Jarrah airbase. In late 2013, reports emerged of claims by Islamist fighters that they had successfully flown two of the captured L-39s. In October 2014, the Syrian Government claimed that at least two rebel-held L-39s had been airworthy and had recently been destroyed by Syrian Air Force aircraft.
According to Reuters, by 2014 the L-39 had allegedly become one of the favoured platforms of the Syrian Air Force for performing ground attack missions due to its slower speed and higher agility over other aircraft in its inventory. In December 2015, following the securing of the Kweiris airbase by government forces, the resumption of ground-attack missions by L-39s in the vicinity of Aleppo commenced shortly thereafter.
On 26 December 2017, a Syrian L-39 was shot down near Hama airport.
On 3 March 2020, a Syrian Arab Army Air Force L-39 was shot down by a Turkish Air Force F-16 over Idlib province. Both Syrian and Turkish forces confirmed the downing.

Civilian use

While newer versions are now replacing older L-39s in service, thousands remain in active service as trainers, and many are finding new homes with private warbird owners all over the world. It has been claimed that the L-39's desirability stems from the fact that it is "the only available second-generation jet trainer". This trend is particularly evident in the United States, where their $200,000–$300,000 price puts them in range of moderately wealthy pilots looking for a fast, agile personal jet. Their popularity led to a purely L-39 Jet class being introduced at the Reno Air Races in 2002, though it has since been expanded to include other, similar aircraft.
In September 2012 there were 255 L-39s registered with the US Federal Aviation Administration and four registered with Transport Canada. Several display teams use the L-39 such as the Patriots Jet Team, the Breitling Jet Team and the Black Diamond Jet Team. There are also several L-39s that have been made available for private jet rides by various operators in Australia, Czech Republic, France, Germany, Spain and the USA. These L-39s are mostly in private hands, but some also belong to government agencies, such as those in Vyazma, Russia. In March 2018 there were five L-39s on the civilian register in New Zealand. One registered as an L-39 and four others registered as L-39C
Since 2004, the Defence & MRO Division of Aero Vodochody has performed a general maintenance, repair and modernisation program of civil-operated L-39s, as well as performing the demilitarisation of ex-military aircraft. Services offered to civil operators include life-extension programs, support for civil registration/certification, training of ground/flight crew, logistics and analysis, customization, routine inspection, condition-based maintenance support, and providing general expertise/consultancy work.

Variants

;L-39X-01 – X-07
;L-39C '
;L-39CM '
;L-39M1
;L-39V '
;L-39ZO '
;L-39ZA
;L-39ZAM
;L-39ZA/ART
;L-39MS/L-59
;L-139 Albatros 2000
;L-159
;L-39NG
;Skyleader UL-39 Albi

Operators

Notable accidents and incidents

;Czech Republic
;Germany
;Lithuania
;United States

Citations