The Il-78 tanker was developed and designed in the Ilyushin Aviation Complex in Russia. The main reason behind its development was an expansion of the transferable fuel load of an earlier version of tanker, the Il-76. The Il-78 has a total transferable fuel load of, which includes from a pair of tanks in the freight hold. In comparison, the Il-76 has a capacity of only. The Il-78 transfers fuel solely through deployment of the probe-and-drogue refueling method.
Variants
;Il-78: The Il-78 was the original production version with two removable fuselage tanks and a maximum transferable load of 85.72 tonnes. ;Il-78T: Alternative designation for Il-78 due to retention of all cargo handling equipment and convertible freight hold. ;Il-78M: The Il-78M entered service in 1987 as a dedicated tanker equipped with three permanent fuselage tanks, a higher gross weight of 210 tonnes, and no cargo door or cargo handling equipment. The cargo ramp is retained but non-functional. Total fuel capacity is 138 tonnes, of which 105.7 tonnes is transferable. ;Il-78M2: Modernization of Il-78/78M aircraft, using same parts as used in newly produced Il-78M-90A and Il-76MD-90A variants, to enhance service life from 30 to 40 years. First modernized aircraft was rolled out on 25 August 2019. ;Il-78M-90A : An upgraded variant based on the Il-76MD-90A. First prototype was rolled out on 29 November 2017, and performed its maiden flight on 25 January 2018. ;Il-78ME: Export version of Il-78M. ;Il-78MKI: Customized variant of the Il-78ME for the Indian Air Force. These Uzbekistan-built planes are fitted with Israeli fuel transfer systems and can refuel six-eight Sukhoi Su-30MKIs in one mission. ;Il-78MP: Multi-role aerial refuelling tanker/transport aircraft, with removable fuel tanks in cargo hold and UPAZ refuelling pods, for the Pakistan Air Force, and Chinese Air Force.
Angolan Air Force – 1 Il-78 ordered from Ukraine in 2001. Disposed of refueling equipment and rebuilt into the Il-76TD standard.
Chinese Air Force – 3 Il-78MPs in service
Indian Air Force – 6 Il-78MKIs in service. The Indian Air Force refers to the aircraft as "MARS" and has raised a new unit 78 Squadron. India is also considering procurement of six more Il-78 after scrapping deal with Airbus.
Libyan Air Force – 1 Il-78Es bought in 1989. The aircraft wasn't seen airborne since 2005.
Pakistan Air Force – 4 Il-78MPs were ordered from Ukrainian surplus aircraft stocks, fitted with removable fuel tanks and UPAZ refueling pods. The first of the four aircraft was delivered in December 2009. A total of four Il-78MPs have been delivered to the PAF as of May 2012.
Ukrainian Air Force – inherited 21 Il-78s after the collapse of the Soviet Union. Since 1993, some of the aircraft were disposed of their refueling equipment and used as cargo aircraft, others were sold to Algeria, India, Pakistan and China for air refueling operations.
* 106th Heavy Bomber Aviation Division – Uzyn Air Base, Kyiv Oblast
** 409th Aviation Regiment of tanker aircraft
An Il-78 of the Ukrainian Air Force was bought and imported by North American Tactical Aviation Inc in 2005, and flown to the United States in July 2006 with an intention to use the aircraft for contracted air refuelling operations to United States military. The aircraft latter passed under ownership of the Air Support Systems LLC and got an American civilian registration N78GF. Afterwards, it was mothballed at the North Texas Regional Airport, Texas for 2.5 years. In 2009, it departed from the airport with a Ukrainian crew hired by NATA and was heading to the Wittman Regional Airport, Wisconsin to refuel before leaving the United States on the way to Pakistan for phase aircraft maintenance. However, it was diverted to the Sawyer International Airport, Michigan where it is grounded until now. In 2010, the aircraft was repossessed by the Bank of Utah Trustee and in 2019 sold to Meridican Inc, an international consulting firm in Philadelphia, PA. The aircraft is currently getting a cockpit upgrade for international operations.
