Airforce base Željava-Bihać was the most important and most expensive military object of
former Socialist Federal Republic Yugoslavia. It was built significant veil of secrecy, as well as
all former Yugoslav’s cold war objects of special purpose, in the period from 1948. to 1968.,
modeled on the Swedish airfield Save near Göteborg, which is today highly visited
aeromuseum (
The main purpose was defense and distraction of potential aggressor on former republic, so
it was always in the interest of foreign secret agencies which is proven today with declassified
records of CIA spy satellites, which was monitoring for years the construction of this object
from orbit.
SFRY was using the airfield to demonstrate power through publicing selected photo and video
materials of object, either in native or foreign publications without announcing where do
materials come from and what they mean. The phrase “underground airfield” was used
frequently, which has contributed to creating an urban myth about planes that ascend directly
from the mountain. Although it is clear that it was only shelter for planes, however really
sophisticated for the time in which it was produced, the myth is still outspraded.
SFRY was also using this airfield, together with other similar objects as a demo, representing
the capability of it’s architectonic-tehnical executive ability, and based on that it was getting
requisitions for building similar objects in other friendly countries as Iraq and Libya.
Complex of the airfield comprises of outer plateau with runways in the foothill of the mountain
Plješevica, underground object “Klek” located in granite womb of the mountain and barrack
remoted 3 km accommodating command base where were situated soldiers and services who
served the airfield and underground object “Klek”.

At Baljevački plateau under the mountain Plješevica, which is naturally furrowed by numerous
sinkholes, there is 5 runways/lanes in total. 2 of them are takeoff-landing (TOL) and other 3
are only takeoff (TO).

 photo zeljava-pregled_hrv_eng-v2014_600x_zpsqfxzhktl.jpg

Direction, lenght and width:
TOL1: 141°-321°, 2500x45m
TOL2: 141°-321°, 2500X24m
TO3: 077°-257°, 2050X24m
TO4: 004°-184°, 2000X15m + 779x12m
TO5: 077°-257°, 2061X15m

TOL1 has system of approaching lights CALVERT in the lengt of 900 metres in front of
groundsill 141° as well as system VASIS lined for the same route 141°, set for supersonic-jet
aircrafts with slope of 3.5°.

The underground object “Klek” was called “Object 505” in the proces of building and it was
delivered uncompleted in full to the use of army during dramatic events of Czech crisis
in 1968., when the invasion of SSSR and Warsaw Pact forces were also threating Yugoslavia.
The unit located there was 117.lap (hunting aviation regiment), and it was moved in a
relatively short period of time from former stem base Plesu to Zagreb during the July of 1968.
117.lap comprised of 124. and 125.lae (hunting aviation squadron) and 352.iae (scout
squadron). It was an elite air force unit of the Ex Yugoslavia which originates from
II. World War and battle of Tito’s partisans against nazis i fascists.
The transfer from airfield of base Pleso to airfield Željava-Bihać was preformed with newly
arrived airplanes MIG-21 F13.

Underground object “Klek” comprises of 4 main interconnected tunnels-galleries (A, B, C i D)
shaped in form of letter “M” and they form the core of object. They are wide 15 to 16 meters
and high 8 to 12 meters (depends of the location). The thresholds of the galleries are also
entrances of “Klek” marked as “entrance 1, 2, 3 and 4”. The core of object provides shelter
and accommodation for 3 mentioned squadrons of airplane 117.lap - and in practice it
approximately meant number of 60(!) airplanes MIG-21.
Dimensions and weight of the doors were truly impressive. Three doors, for galleries A, B and
C were thickness of 60cm, width of 20m and height ~4m, weight of ~100 tons and they are
driven by an electric way. The door to the gallery D are working on the principle of hydraulics
and had a thickness of 80cm, width 20m, height ~9m and weight them was assumed to
exceed 100 tons. These door are covered whole profile of gallery D unlike all others.
125.SQDN was located in the gallery A, 124.SQDN in the gallery C and 352.SQDN in the
gallery D.
The core of object is protected from outside world and completely hermetically separated
(in case of nuclear war) by dint of four heavy concrete-reinforced armored doors which
protected entrances of the galleries, and they were powered by electro-mechanic-hydraulic
Dimension and weight of the doors were truly impressive. Three of doors for galleries A, B i C
were 60 centimetres thick, 20 metres wide and ~4m tall, heavy ~100 tons and were used by
electricity. The doors of the gallery D worked on hydraulic principle and they were 80
centimetres thick, 20 metres wide and ~9 meters tall. The weight was assumed to be more
then 100 tons. Unlike others, those doors covered all profile of the gallery D.
Today, after the destruction of the airfield on 16.05.1992., all these doors are destroyed,
except the one on the entrance in the gallery C (entrance 3), and by its remains it is evident
how impressive concrete-reinforces structure was.

Approching hallways of object’s core are derived in mild radius and end with extesions, in
front of the armored doors, located overside. Approching hallways are arhitectural made so
its main purpose is to reduce percussive, destructive wave that would arise after detonation
of nuclear weapon near airfield.
Available data suggest that such protection could effectively protect the core of the object in
case of detonation of a nuclear device with power of max. 20kt at the plateau Baljevac where
the runways are located.
Except three squadrons in the galleries with ~60 planes, there were located ancillary services:
-aircraft workshop (VTR in the exstension of the entrance 2, at the end of the gallery "B" and
the second one in the access hallway for gallery A, entrance 1) and other and other facilities
that were used by mechanics to maintain the aircraft
-fuel warehouse with 5 large tanks at the entrance 3 with pipelines to aircraft parking spaces,
so that the aircrafts could be refueled inside the facility
-station for missile testing and weapon preparation for airplanes in acces hallway of entrance 2
-13 air conditioning stations with specially protected ventilation exists on hillside of mountain
-two diesel power stations: DIT-1 at the entrance 1 (625 kVA) and DIT-2 at the entrance 3
(1000 kVA)
-11 to 13 verticals that were using air chambers for intake of outside air, outlet for noxious
gases from diesel generators and a few with unknown purpose. All verticals are coming out
vertically from the underground facility on the slopes of the mountain above and some were
as high as 200m(!)
-boiler room and battery charging stations
-fighter regiment command
-technical operational center (TOC) charged for maintenance of facility

In the command part "Star", whose entrance is located in the gallery D, there were:
-operating center
-photo laboratory for developing films exposed on reconnaissance flights
-communication center with teleprinters and cryptography
-parachute section and storage
-squadrons commander offices and classrooms for pilots
-kitchen, doctor ...

The speciality of the underground object "Klek" is acces to airport control tower (AKL), which
is constructed in the form of elevator entry from gallery C on 60metres of height from the
level of the entrances and runways outside. The space itself and control tower window is
buried in rock slopes of the mountain Pljesevica.

Within the airfield there was the mentioned barrack, located 3 km from the complex of
runways and object "Klek". There were 34 buildings, garages, workshops, boiler rom, auxiliary
objects for accommodation of active military personnel and techniques. The barracks was in
the exclusive function of the the AFB.
Radar stations and communication centers at the top of the mountain Plješivica, on the hill
Čalopek, object "Jasen" on angle 377 and position "Abdić hill" were also an integral part of
the AFB complex.
As part of the AFB and its function were also underground fuel tanks in the hill Pokoj above
the Bihać city and warehouses ordnance : air bombs, missiles, cannon and machine-gun grain
in the Vedro Polje.

All together mentioned locaities have experienced evil fate when the whole complex was
mined and extremely damaged with more than 50 tons of explosives on 16th May 1992. in
the beginning of the outbreak of war in Bosnia and Herzegovina.
Top army leaders of the Yugoslav army, whose structure was severely compromised in
previous war events in Slovenia and Croatia, made the decision about the dislocation of
planes, equipment, units and civilians affected by war threats on location in Serbia.
All that is left on the ground should have been mined and permanently disabled.

Today, in the post-war period "Holes", how this location call former and current residents of
this regions, gradually reveal their secrets to curious researchers of artificial underground
objects. Researchers are fascinated with construction (because this is certainly an example of
military architecture that deserves more attention and care through the formation of
museums and inclusion in the tourist offer), complexity, but also simplicity and functionality of
the details (air conditioning, ventilation systems, sewage, fresh water, electricity).
The effort invested in finding a variety of documents, as well as the testimonies of people who
have worked on this AFB complex made exclusively for military use, requires a good deal of
time of cabinet work after research in the field.
So in this context we from LYBI group of enthusiastic researchers (
have a special honor to present a series of photo-documents which show very beginning of
operations of this AFB complex. This is a real rarity from 1968., 1969. and in 1970., which we
haven't encountered anywhere during many years of reashrces.
We got an exclusive license for public presentation of these materials for
educational purposes.
Used photos are the property of Croatian State Archives (CSA) from the Collection of photos
of 5th Army District HR HDA 1211
On these photographs can be seen brand new AFB Željava-Bihać and part of them were made
during visit of Josip Broz Tito on 3rd May 1969.
Through the presentation of these photos and its details we have introduced one section of
photo-video documents that we have made all these years, which shows the current state
of locations from those photos.
As time goes by nature itself back what was taken away from her.

On the end of these text we send a special greeting to all our friends we met while working
on this issue...especially to those from Bihać city area.