of new-built aircraft and the refurbishment and upgrade of 60 used and serving aircraft was expected to be complete by 2010–2012, as per the Pakistan Air Force Air Chief Marshal Tanvir Mahmood Ahmed. In April 2006, Janes Defence Weekly reported that the PAF may procure an additional 18 Block 52 aircraft. In July 2007, Commander of Central Command Air Forces, Lieutenant General Gary L. North (U.S. Air Force), and another U.S. aviator flew a pair of F-16s to Pakistan for Pakistan Air Force. In December 2009 the first F-16/D block 52 rolled out for PAF. The first batch arrived in Pakistan in May 2010, and 17 F-16C/Ds had been delivered to the PAF by the end of December 2010. One F-16D used for testing joined the PAF in 2012 along with two examples upgraded to MLU standards in the USA. In April 2014, the PAF received a batch of five second-hand F-16s bought from Jordan, from an order for 13 aircraft. In 2016, the US approved the sale of eight F-16 Block 52 (two C and six D models) to Pakistan for $700 million. Pakistan had hoped to acquire the 8 F-16s for $270 million instead, with the rest being subsidized by Coalition Support Funds, but the US declined to subsidize the sale, and the deal fell through. In 2019, the US approved a $125 million deal with Pakistan to provide technical support to existing F-16s. Singapore The Republic of Singapore Air Force began as a small F-16 user, but has a steadily growing fleet. It has operated the aircraft since 1988, when the first of its initial order for 8 F-16A/B-15OCU arrived. A Mid-Life Upgrading program is ongoing since 2015 when Lockheed-Martin was selected to upgrade the fleet, and expected to complete in 2023. The Singapore Foreign Military Sales program is known as PEACE CARVIN. South Korea Facing a need for advanced aircraft to counter North Korea's numerical superiority, the Republic of Korea Air Force ordered 36 F-16C/D Block 32 aircraft in 1981 (later four F-16Ds were added by profit from exchange rate fluctuation), making it the first operator of the C/D model outside of the United States. A more ambitious program (Korean Fighter Program) aiming to provide 120 new fighters was initially lost to the F/A-18 Hornet, but various difficulties led to the order going to the F-16C/D Block 52D (KF-16C/D), 72 of which were to be manufactured