The areas where Wojskowe Zakłady Lotnicze Nr 4 S.A. (Military Aviation Works No. 4 JSC) has been placed were under ownership of State Treasury and from 1945 under management of Ministry of Defense.
It was back then when Soviet Overhaul Military Base was set up to deal with overhaul of aircrafts stationed on Bemowo airfield. But as soon as on June 27th 1951 the base was handed over to Polish Army and renamed Aviation Overhaul Base (abbreviation in Polish – LBR), Military Base No. 1317.

Evolution of company’s name

1951 - 1954

Aviation Overhaul Base

1954 - 1957

Military Aviation Overhaul Base

1957 - 1982

Overhaul Aviation Works No. 4

1982 - 2008

Military Aviation Works No. 4

2008 - now

Military Aviation Works No. 4 JSC
In July 1954 the name LBR was changed to Military Aviation Overhaul Base (WLBR) and on 1st April 1957 changed again to Aviation Overhaul Works No. 4 (LZR-4). That name lasted until 1982 when once again new one was introduced, this time Military Aviation Works No. 4 (WZL-4).
Then in the process of commercialization based on the act issued by Minister of Treasure on 26th October, 2007 Wojskowe Zakłady Lotnicze Nr 4 S.A. (Military Aviation Works No. 4 JSC) has emerged. The name has been in force since 2008.

Serviced by WZL-4 between 1951-2019


50s and 60s were periods of growth for Aviation Overhaul Base.  Back then company performed MRO services of: airframe, engines and arms to aircrafts used by Polish Army. At the very beginning those were aircrafts from II World War era but since mid-50s radical technological change took place in aviation sector that manifested itself through introduction of jet engines. Those engines quickly displaced piston engines on war planes therefore as soon as in 1954 WLBR introduced MRO services of jet engine RD-500 powering Jak-17 and Jak-23 aircraft.

The growth of WLBR was simultaneous to development of polish military aviation. In the next few years company expanded its offer to MRO of: MiG-15, MiG-15bis and Lim-1, Lim-2 , Lim-5 aircrafts and RD-45 and WK-1 engines and their polish equivalent: Lis-1, Lis-2 and Lis-5 engines. In 1957 also overhaul of IL-28 bomber started.


In the mid-60s, because of separation of LZR-4 from its airfield, MRO services of aircraft’s airframes were ceased and company focused on engines. In 70s and 80s MRO of new generation engines was mastered. Those were: R-11, R-13 and R-25 engines to jet fighter MiG-21, turboshaft GTD-350 engine powering Mi-2 helicopter and MRO services of low-power turbines to military land vehicles were introduced (DG4M-1, GTD-5(M), 2PW8-1 and 9I56-3).

Also company provided overhaul of airfield equipment and produced tutorial accessories for land forces.


90s were another prolific period for WZL-4 S.A. Company perfected already implemented MRO processes and introduced new ones along with new technologies for more sophisticated and more powerful jet engines.

Apart from continuation of MRO services of “R” series and GTD-350 another three engines were introduced: AL-21F3 (SU-22), TW2-117 A/AG (Mi-8) and RD-33 (MiG-29).

The enterprise also put a lot of effort and money to expand its services to jet engines’ ground testing. In 1992 new facility was built that could run tests of jet engines of performance up to 15 000 daN. It was used to test AL-21F3 engine and after small upgrade also R-11 R-13 and R-25 engines.

90s were also the times when WZL-4 began overhaul and repairs of starter engines: TS-21 (SU-22) and , AI-9(W) (Mi-24).

New investments, new markets

This period lasts since the end of 90s and has started with another upgrade of engines’ testing facility the purpose of which was to enable testing of RD-33 (MiG-29) engine (after MRO) with digital control and recording of its parameters.

In 2000s company business model changed as an effect of changes in Polish Air Forces and Polish Army in general. It was the time when strategic decisions were made to change the supplier of arms and martial technology in favor of those from ‘western’ side of the world. As a result the company first service performed on ‘western’ military aircraft engine was a series of control tests of F100-PW-229 (F-16 C/D) engines.

Significant breakthrough moment was opening for new, commercial markets which effected in joint project of: WZL-4, Central European Engine Services, General Electric and Polish Airlines LOT to build new, sophisticated engines’ testing facility which could be used to test new generation military and commercial jet engines with a mass air-flow up to 600 kg/sec and maximum thrust of 330 kN. First product tested was Boeing 737 engine CFM-56-3.

Another important collaboration was 2010 offset agreement with Avio S.p.A to participate in the production process of the GE90 and GEnX-2B PIP – nozzle guide vanes to low pressure turbine of engines powering Boeing 777, 747 and 787.

Into the future

The company has a huge potential for development. It continuously invests in: new facilities, equipment and employees to expand its capabilities and offer. All to keep current customers and reach out to new ones.