Airfield Zeljava-short description

Airfield Zeljava was build in utmost secrecy between 1957-1968.
"Klek" is the name for the underground part of this airfield, largest in Europe even today.
It is situated near city of Bihac, right on border between Croatia and Bosnia and Herzegovina.
Complete lenght of underground tunels is 3500meters.
Complete underground facility had 4 entrance/exit tunells conected with passageways of which 3 were used for aircraft.
Tunnel 1, 2 and 3 could been hermeticaly sealed with electric movable heavy concrete and steel armored doors of dimensions;
~0.6meters (thickness), ~20meters (lenght), ~4meters (height), ~100tonnes (weight).
Tunnel 4 had heavy hydraulic movable concrete and steel armored door with dimensions;
~0.8meters (thickness), ~20meters (lenght), ~9meters (height), probably more than 100tonnes (weight) and they had covered full cross section of the 352nd.Recon SQDN gallery.

Airfield had 2 take-off/landing (ICAO standard) and 3 take-off runways.
It was protected against all conventional weapons and 20kt ground nuclear explosion.
For this reason 3 of 4 tunnels had built in so called "nuclear chamber" which amortised the blast so heavy doors wouldn't be hit with blast of more than 3 atmosphere.

Distance between two enty/exits was constructed so that it prevented simultaneous destruction of two tunnels.
Rooms inside the base were closed by 56 heavy armored doors.
3 main gallerys could contain about 60 planes and they were connected in shape of M with elongated middle line (Air forceTechnical workshop-for chekup and service of lanes) with additional gallerys on the side.
Dimension of the main gallerys is ~8meters (height), ~16meters (width).
Main junction point inside the object "Klek" (connection beetwen 124th. and 125th.Fighting SQDN gallery with central gallery) has ceiling about 15 meters.
Nuclear chambers have ceilling taller more than 15 meters.

Inside of the tunnels planes were moved by electric towing vehicles, outside by their own power.
Each parking place in the tunnel had its own fuel pump for kerosene.
Each of 3 strenghtened squadrons had it's own preparation space (briefing etc.).
Inside the underground facility was a kitchen and mess hall.

Basic living and working conditions for entire base (completly autonomus) were provided for 30 days:
-electric, water supply, sewage
-2 reserve diesel/electric generators (1000kVA and 625kVA)
-ammunition & spare part storage
-room for decontamination of airplanes
-13 clima-chambers with especially protected ventilation shafts (in the same time they use as a emergency exists from underground facility)
-also exists ventilation shafts for exhaust gases generated by diesel generators and similar
-accumulator charge station
-operations and communications centre
-parachute section and para storage
-station for rocket inscpection
-diesel fuel storage
-distribution network for kerosene
-boiler room
-...etc. (eveything what any underground base with 2000+ personell needs to have to be complety independant in case of nuclear war together with testing facilities....)

External ammunition depo was located in near by (5km distant) village of Vedro Polje.
Kerosene fuel was transported by special pipe line of ~20km long from underground fuel depot on Pokoj hill near city of Bihac.
Kerosene inside "Klek" facility was stored in 4 (100tonnes each) cilindric steel tanks based on so called "aqua-system" to minimise risk from fire or explosion.
Today those remain kerosene in the pipeline and tanks inside "Klek" cause polution of drinking water wells for city of Bihac, especially after heavy rain (wather has taste on an oil).

Base was extensivly used during war against Croatia and that was, ironicaly, only usage of this base in a war time.
With outbreak of war in Bosnia and Herzegovina geostrategical postion of the base was untenable.
YPA evacuated all planes, technics and personnel to Serbia & Montenegro.
Outside objects (command base) were given to Croatian Serb army and other parts of the oustisde objects was under control of Bosnian Army.

On saturday 16.may.1992, with 56 tonnes of explosives, YPA destroyed infrastructure of the airfield which was worth, most probably, about up to 4 billion US$.
Detonations, few hours long, was so strong that whole Bihac area was shaked like it was a strong earthquake.
The Europe's largest underground airbase was (most probably irreversible) destroyed.