MELBOURNE, Australia — The U.S. Air Force has completed regeneration work on the last of 24 Lockheed Martin F-16 Fighting Falcon aircraft for Indonesia, ending a five-year program that has brought the former U.S. Air Force and Air National Guard jets up to modern standards.

The jets will now be delivered to Indonesia via a five-day trans-Pacific flight and will require midair refueling and two overnight stops from the Ogden Air Logistics Complex in Utah, which regenerated the Block 25 aircraft and upgraded them to Block 52ID standard.

The aircraft, consisting of 19 single-seat F-16Cs and five F-16D two-seaters, were drawn from former U.S. Air Force and Air National Guard aircraft that had been withdrawn from service and stored at the 309th Aerospace Maintenance and Regeneration Group boneyard located at Davis-Monthan Air Force Base in Tucson, Arizona.

These were offered to Indonesia in 2011 under the U.S. Excess Defense Articles program, with the upgrade package including the installation of a new modular Mmission computer, Link 16 data links, Raytheon AN/ALR-69 radar warning receivers, Terma AN/ALQ-213 Electronic Warfare Management Systems and BAE Systems AN/ALE-47 Countermeasures Dispenser Systems under a Foreign Military Sales package worth $750 million.

The aircraft’s AN/APG-68 radar is also being upgraded with enhanced capabilities under the upgrade program.

Deliveries of the first aircraft to Indonesia began in mid-2014, with further deliveries in 2015, 2016 and March this year. One F-16C was written off in April 2015 when its undercarriage collapsed and the aircraft caught fire during takeoff at Halim Perdanakusuma air base near the capital Jakarta, reportedly due to the poor condition of the runway.

The Indonesian F-16s are currently serving with the Indonesian Air Force’s 3 and 16 squadrons alongside the survivors of eight Block 15 F-16A/B aircraft acquired in the 1980s.

Indonesia recently announced it will be acquiring the Lockheed Martin Sniper Advanced Targeting Pod for its F-16s, and the country has been cleared to acquire both the Raytheon AIM-9X Sidewinder and AIM-120 air-to-air missile.

The Southeast Asian country, which comprises of a vast archipelago with more than 17,000 islands, has requirements for more fighters although it favours the Russian Sukhoi Su-35 Flanker, which it is negotiating to buy under a partial barter scheme. Indonesia already operates the older Su-27 and Su-30 versions of the Flanker in its Air Force.