Advanced Medium-Range Air-to-Air Missile

The Advanced Medium-Range Air-to-Air Missile, or commonly called XMAA, is a kind of special weapon in Ace Combat that appears since Ace Combat 04, and has been featured in almost all the games since then. The prominent feature of XMAA is that it has a medium-long range (15000 feet/1850 in Ace Combat 04), and an ability to lock-on to multiple air targets at once. Combined with the fact that it has a damage double of a standard missile, it can easily one-shot most airplanes from afar with ease. However, its maneouverability is very limited compared to Standard Missiles, so that XMAAs are much less effective when launched from angles other than head-on/tail-on

In Ace Combat 6 and Assault Horizon, there are two variants of XMAA: XMA4 (4AAM in AH), and XMA6 (6AAM in AH) that lock-on to 4 and 6 air targets respectively. However, as in Assault Horizon, it is still unknown whether the 6AAMs are XMAAs or XLAAs as they all appear on aircraft equipped with XLAA (Su-35S, F-14D, and EF-2000).

Those missiles are based on AIM-120B/C AMRAAM for US Aircraft, and Vympel R-77 (AA-12 Adder) on Russian Aircraft

Ace Combat 04: Shattered Skies
The XMAA first appeared in Ace Combat 04 as an SP weapon of F/A-18C, which is unlocked after the 6th mission, so that it is pretty easy to acquire. However, due to its considerably shorter lock-on distance than XLAAs there's much less time to launch it before the target can get too close. Especially at high speed.

List of aircraft equipped with XMAA in AC04:
 * F/A-18C
 * F-15C
 * F-15E
 * F-15 ACTIVE
 * Rafale M
 * F-22A

Ace Combat 5: The Unsung War
The XMAA probably appears for the first time on F-16C Block 60, which is available after filling the killbar of F-16C family

List of aircraft equipped with XMAA in AC5:
 * F-16C Block 60
 * F-15 S/MTD
 * F/A-18E
 * F-22A