The Croatian Air Force ( or HRZ) is a branch of the Croatian Armed Forces whose primary task is to ensure the sovereignty of the airspace of the Republic of Croatia and to provide aviation support to other branches in the implementation of their tasks in joint operations. It is also the carrier and the organiser of the integrated anti-aircraft defence system of the Republic of Croatia. Aviation history The Croatian Air Force as it is known today was established on 12 December 1991, during the Croatian War of Independence. After 2003, a large portion of the fleet was modernised or completely overhauled and the rest of the outdated fleet was retired. Croatia also acquired new-build transport helicopters, fire-fighting aircraft and basic training aircraft during this time. The planned acquisitions for additional fixed and rotary-wing transports and fighter aircraft were repeatedly postponed due to a difficult economic situation. Duties The primary role of the Croatian Air Force is securing the sovereignty of Croatian air space and providing air support to other services during joint operations. It operates the integrated Croatian Air Defence system. Other tasks include providing help in natural, humanitarian and technological disasters, search and rescue operations, and support to other government agencies. Status The core of the air force is a squadron of 12 modernised MiG-21 fighters. In 2003, a minor upgrade and an extensive overhaul were performed in Romania, incorporating navigation and communication elements of the Lancer standard to make them interoperable with NATO air forces. The aircraft received no upgrade to their weapons systems. Despite initial plans to replace the MiG-21 fleet with a multirole aircraft in 2013 (delayed from 2011 due to the financial crisis) and an official tender having been issued in 2008, ongoing budgetary constraints have resulted in an abandonment of these plans. As a cost-saving measure, a decision was made to again overhaul seven serviceable airframes already in service and supplement them with five additional airframes from Ukrspetsexport. This temporary measure will see the fleet remain in service only until 2019–2020. Pilot training is conducted on two types of aircraft. During late 2007, five new Zlin 242L Aerobatic basic trainers were acquired in order to replace a fleet of seven old Utva 75s (four had already been retired previously). The deal was worth just under $2 million. An option for three additional basic trainers was considered but has not been exercised. The