a single crew on a single day, representing an average of one drop every three minutes for the duration of eight hours. Commanders Commanders of the Croatian Air Force since its establishment in 1991: Imra Agotić (1991–1996) Josip Čuletić (1996–2001) Josip Štimac (2001–2002) Viktor Koprivnjak (2002–2007) Vlado Bagarić (2007–2011) Dražen Šćuri (2011–2016) Miroslav Kovač (2016–2017) Mato Mikić (2017–2019) Michael Križanec (2019–present) Structure Air Force and Air Defence Command, in Zagreb Command Company, in Pleso (Zagreb Airport) 91st Air Force Base, in Pleso Command Company Fighter Aircraft Squadron, flying MiG-21bisD/UMD Multirole Helicopter Squadron, flying Mi-171Sh (at 94th Air Force Base, in Lučko) Aeronautical Technical Battalion 93rd Air Force Base, in Zadar Command Company Transport Helicopter Squadron, flying Mi-8 MTV-1 (at 95th Air Force Base in Divulje) Aircraft Training Squadron, flying PC-9M, Zlin 242L Firefighting Squadron, flying CL-415, AT-802A/F FireBoss Combat Helicopter Squadron, flying OH-58D, Bell 206B-3 Aeronautical Technical Battalion Airspace Surveillance and Control Battalion, at 91st Air Force Base Airspace Surveillance Center, in Podvornica, reports to NATO's Integrated Air Defence System CAOC Torrejón in Spain Sector Operation Center, in Split to coordinate with the Croatian Coast Guard Mount Sljeme, Borinci, Papuk, Učka and Mount Rota radar posts with AN/FPS-117 radars Radio-technical Maintenance and Support Company, at 91st Air Force Base Air Force Training Center "Rudolf Perešin", at 93rd Air Force Base MiG-21 replacement acquisition Although the MiG-21 was perceived as an outdated fighter by the Croatian Air Force even in the late 1990s, budget constraints have been continuously deferring any final decision on the acquisition of a new fighter type. As Croatia was no longer facing any military threat, serious talks were started with Israeli firms to extensively upgrade the fleet of 24 MiG-21bis/UM fighters to a "Lancer 3" standard instead of buying a completely new combat aircraft. Although the initial information suggested that such a decision was practically final, no agreement was reached. By late 2002 all 24 MiG-21's were reaching the end of their service lives and it was decided that the fleet be overhauled and lightly upgraded in Romania. A first squadron of 12 aircraft was therefore sent for 10-year life prolongation repair to Aerostar after which the second squadron was to follow. But after the first squadron arrived to Croatia, no further moves were made in order to revamp the second squadron. As the fleet of 12 overhauled MiG-21s was originally planned to remain active only until