by Allan Ng
(with ST Priestley)
Canadian Defence Procurement – December 2003
The CF18 Incremental Modernization Program – In Detail
Follow-Ons to the Engineering Change Proposal 583 – Short-Range AAMs?
Allan Ng reviews DND's CF18 fighter aircraft
modernization plan (Part 8)
AAM – X Marks the Spot?
In order to take advantage of a JHMCS (Joint Helmet- Mounted
Cuing System ), the CF would need a next- generation short-range air- to-air missile (AAM) as well.
The CF's currently-serving short-range AAM – the infrared-guided AIM-9M Sidewinder –
is simply incompatable with the JHMCS.
As previously mentioned, the field-of-view of a Sidewinder infrared seeker-head is restricted to
a cone fanning outward roughly 30° from that missile's nose. Any
AIM-9M fired outside those para- meters is unlikely to successfully track its target. Newer short-range AAMs
with a wider field-of-view slaved to the JHMCS would allow pilots to gain a missile 'lock' with a
glance. In tests, successful locks have been gained on targets more than 90 degrees off the nose infrared seekers
of this new generation of AAMs.
The US short-range AAM designed to integrate with the JHMCS is the AIM-9X, an extensive redesign of the AIM-9M.
The key differences are the AIM-9X's use of MIL-STD-1760 link
(like the AIM-120 medium- range AAM) and, most importantly, an
ability to take infrared cuing from the JHMCS.  These 'Off bore- sight' launches require
much more manoeuverability. To allow the AIM-9X to make such hard turns, thrust vectoring – ie:
redirecting the rocket motor's efflux – has been added to assist the missile to manoeuvre.
 The AIM-9X can be used without the JHMCS but then operates basically as an AIM-9M. An AIM-9X
interface does require modification of CF18 launch rails. Raytheon was contracted ($21M) to modify
CF LAU-115 (wing pylon) and -116 (fuselage station) launchers for the "latest weapons" between 2001 and 2006.