Airforces Monthly - February 2017

WZL-2 MRO FACILITY
Polish
MRO Experts
BASED IN the Polish city of Bydgoszcz,
Wojskowe Zakłady Lotnicze 2 (Military
Aviation Maintenance Works No 2;
WZL-2) is perhaps the finest maintenance,
repair and overhaul (MRO) facility of its
kind in Eastern Europe. It’s currently
occupied with routine maintenance,
service life extensions and avionics
upgrades for Soviet-era combat jets.
A primary partner of the Siły Powietrzne
Rzeczypospolitej Polskiej (SPRP; Polish
Air Force), WZL-2 ensures safe, continued
operation of the Su-22 Fitter fighter-bomber,
MiG-29 Fulcrum fighter and C-130E Hercules
transport fleets. It repairs and overhauls
60 different parts and assemblies for Polish
F-16s and is preparing to take on depotlevel
maintenance and repair for this type.
The state-owned plant has an 800-strong
workforce and is controlled by the Polska
Grupa Zbrojeniowa (PGZ; Polish Armaments
Group). Set up by the government in
2014, PGZ united the state-owned defence
industry to ensure growth in capability.
Wojskowe Zakłady Lotnicze 2 is well
equipped to carry out overhauls,
service life extensions, inspections and
upgrades on the MiG-29 and Su-22M4/
UM3K, although it receives no technical
assistance from the types’ design
bureaus or manufacturing plants.
It compensates for this through
co-operation with aircraft repair plants
and spare parts suppliers in former
Soviet countries including Ukraine,
Moldova and Belarus, purchasing vital
spares and gaining maintenance knowhow
and engineering assistance.
Overhauls involve disassembly, detailed
inspection and repair of aircraft structures
and associated stripped-down parts and
systems, followed by reassembly. Ground
and flight testing complete this process,
the organisation using SPRP pilots for
post-maintenance functional check flights
(FCFs) or developmental test work.
Most damaged or worn-out parts are
repaired in WZL-2’s workshops, which
have a production capability that currently
manufactures 20,000 different parts. The
plant’s catalogue varies from simple seals and
packings in rubber and plastic to complex
metallic parts and electronic components.
It’s equipped with modern, digitally
controlled machinery, including threeand
five-axis milling machines and lathes
to produce complex, load-bearing metallic
parts such as components for the airframe
and landing gear of the Su-22 and MiG-29.
In most cases the parts are reverseengineered,
the dimensions and shape
of the original being acquired through
precise measurement by 3D laser
scanner. A digital model is then created
and the original material analysed before
stress tests are conducted to select
material for the new component.
Production usually employs new materials
selected by WZL-2’s engineers. The
digital model is then used in
conjunction with computercontrolled
milling machines
and lathes, and finishing
processes are followed
as required.
New parts pass
through a strict certification process
before final approval from the SPRP’s chief
engineer. Most are produced for MiG-29s
and Su-22s undergoing heavy maintenance
or life extension, but the SPRP occasionally
orders them for installation at squadron level.
Ground support equipment, including
complicated electronic test stands for the
MiG-29, have been developed, manufactured
and repaired. The plant’s Fulcrum equipment
replaced 1970s-vintage Soviet kit.
Production Director Jędrzej Kowalczewski
says that, after 25 years at WZL-2, he
believes overhauling old aircraft is
more difficult than manufacturing new
airframes. He told AFM that frequent
manufacturing defects, damage and wear
and tear must all be fixed at the plant.
This is sometimes a protracted and
difficult process, but Kowalczewski says
WZL-2 has robust capabilities to overcome
issues. It also has the most modern paint
80 FEBRUARY 2017 #347
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