April 27, 2013: Singapore has ordered another 20 AIM-9X Block II Sidewinder and 100 AIM-120C7 AMRAAM air-to-air missiles for its 98 American F-15 and F-16 fighters. The AIM-9X-2 is the latest version of the Sidewinder, a missile that has come a long way since it first appeared in the 1950s. The 9X-2 can lock-on-after-launch. That is, the missile can be fired and then directed to a target via a datalink. That means it can be fired at ground targets or at an enemy aircraft behind you. The X-2 version also makes improvements in the warhead fuze and other components. As impressive as all these features, most are already found in similar missiles made in several other countries (including Russia and China). In effect, the X-2 version is just keeping up. What the U.S. sells, in addition, is an impressive track record of reliability and actually performing as expected in combat. Over 4,000 X model Sidewinders have been built since it entered service in 2003. Block II (X-2) entered service four years ago. Singapore has already ordered nearly a thousand AIM-9 and AIM-120 missiles. The current order is costing $1.8 million per AMI-9X and $2.1 million per AIM-120C7. This includes technical services and support.

The AIM-9 is a heat seeking missile and the heat sensors have become much more sensitive since the first AIM-9s. The current versions of the missile work by detecting a heat source at the point where the pilot is looking. This is done using the JHMCS (Joint Helmet Mounted Cueing Systems), which allows a pilot to see, displayed on his visor, critical flight and navigation information. Sort of like a see-through computer monitor or HUD (Head Up Display). Most importantly, the pilot can turn his head towards a target, get an enemy aircraft or ground target into the crosshairs displayed on the visor, and fire a missile that will promptly go after the target the pilot was looking at. For Sidewinder the pilot has to be looking at something giving off enough heat to catch the attention of the missile's heat sensor. With the X-2 the pilot can launch the missile before he has located the target via the JHMCS, saving a critical few seconds.

AMRAAM is a longer range radar guided missile that weighs 172 kg (335 pounds), is 3.7 meters (12 feet) long, and 178mm (7 inches) in diameter. This is considerably larger than the 85.3 kg (188 pound) Sidewinder, which is about the same length but only 127mm in diameter. AMRAAM has a max range of 70 kilometers. U.S. aircraft use the AIM-120D while export customers get the C7 version.

Eight years ago Singapore decided to order a dozen two-seater F-15SG fighter-bombers and then 12 more to complement the 74 F-16s it already had. The last of the F-15SGs arrived last year. The F-15SG variant was a configuration that was unique to Singapore and was the most advanced variant of the F-15. The two-seat F-15SG had high-end electronics comparable to the F-15E it was based on.