AIM-9X Block II Performing Better than Expected

The Raytheon AIM-9X Block II Sidewinder is about halfway through its operational testing and, thus far, the weapon is performing better than expected with one exception, the US Navy says.

"AIM-9X Block II missile has accomplished approximately half the planned objectives of operational test (OT) and is on track to complete on schedule by the end of the [third quarter] of 2013," says the Naval Air Systems Command (NAVAIR), which manages the dogfighting missile for the US Department of Defense. "Analysis completed to date indicates that the missile is exceeding performance requirements in all areas, including lock-on after launch (LOAL)."

The Block II's improved LOAL capability, which allows a fighter to launch the weapon without the missile's infrared seeker head locked-on to the target, will help US pilots to engage enemy aircraft from increased ranges compared to the older Block I AIM-9X.

The Block II incorporates a data-link similar to the one found on the Raytheon AIM-120D AMRAAM, which enables it to receive target updates from the launching aircraft. The addition of the data-link helps to boost LOAL performance and enables pilots to take advantage of the full kinematic performance of the AIM-9X missile body-which is described as "near" beyond visual range.

So far, pending the final analysis of the test data, the new AIM-9X "has performed as designed in 21 of 22 combined developmental test (DT) and OT live fire events," NAVAIR says. "Seventeen of those 22 live fire attempts have resulted in the missile guiding to a lethal target intercept in aggressive scenarios, most of which exceeded the previous AIM-9X Block I capabilities."

NAVAIR notes that since the beginning of operational testing, five of seven live fire attempts appear to have guided to a lethal target intercept.

But there is one area where a software fix is needed. "Prior to the start of OT [operational test], a valid deficiency was identified regarding AIM-9X Block II helmetless high off-boresight (HHOBS) performance," NAVAIR says. "Although HHOBS is functioning well in Block II, its performance appears to be degraded from the superior performance seen in Block I and will be improved with a planned software clean-up build at the end of OT [operational test]."

The HHOBS capability is of critical importance to the US Air Force, which according to the Pentagon's director of Operational Test and Evaluation 2012 report, initially identified the short-fall. The USAF's prized Lockheed Martin F-22 Raptor air superiority fighter will not have a helmet-mounted cuing system when it receives full AIM-9X capability in 2017 (though a "rudimentary" AIM-9X capability is expected to be added in 2015). Thus Raptor pilots will need to rely on the AIM-9X's HHOBs ability.

NAVAIR notes the HHOBS deficiency does not impact any other Block II capabilities.

By:   Dave Majumdar Washington DC