Much like Bomber Intercept missions and Ace Battle missions, you have to pursue the Aconcagua as it moves around the map screen. It stays within the Intercept missions east of Daeira Airbase and using a plane with a range of at least 2 will make it easier to catch up to. This mission can be difficult since there are numerous moving ground targets that constantly shoot bullets and, in the case of the Aconcagua, numerous missiles at you. A slow plane like the F-117 Nighthawk is personally recommended for this mission by me since they make it easier to follow the enemy vehicles from a safe distance behind without getting too close and destroy them. The mission is completed once all vehicles are destroyed.
- Destroy all vehicles before they escape.
The reward for this mission is 200,000 credits plus a variable amount depending on the number of enemies taken out and, in the case of the planes, how they were taken out. Under a Cloud Umbrella is unlocked. The F-22 Raptor and the Tornado ADV are also unlocked for 410,000 credits and 310,000 credits respectively.
It seems the United Forces has moved a new type of mobile battle fortress to the front. The new fortress is called "Aconcagua," and possesses both attack capabilities and the ability to act as an aircraft carrier. We have information that it is moving freely about the deserts in Elesia (erroneously written as 'Elcia' in-game). Since we are currently in a deadlock over control of the deserts, we cannot allow the enemy to bring such a high concentration of military strength to bear. Your duty is to find this "Aconcagua" and neutralize it. Over and out.
Delta Leader: (When mission is selected on the map) We have confirmed the location of the enemy mobile fortress "Aconcagua," and are now taking strategic action. We're expecting heavy anti-aircraft activity, so take care.
Unknown: 18 bogeys confirmed. Could be first wave of Allied Forces attack!
Aconcagua Commander?: Intercept! Don't let them approach!!
[three Allied Forces planes appear and approach the Aconcagua and one of them tries to attack it with bullets]
Flight Leader?: Number 3, your altitude is too low! Number 3, pull up!!
Number 3: I can't! Aaaahh! [crashes into the Aconcagua and is apparently killed]
[pre-mission cutscene ends]
Delta 2?: Pursue the enemy aircraft carrier! (If the Aconcagua is not destroyed within approximately 4 minutes and 2 seconds into the mission) Enemy aircraft carrier escape successful.
[mission fails once time is up and that coincides with the Aconcagua's escape]
[mission is completed once all targets are destroyed]
Main article: Fortress on the Sands/Soundtrack
- This is the only mission in the NTSC-U version of the game to have a time limit of five minutes instead of the usual ten. In the PAL and NTSC-J versions, secret missions have time limits of seven minutes and intercept missions and Bomber Intercept missions each have time limits of five minutes while other missions except this one have time limits of ten.
- The Aconcagua, Trisul and Logan all appear to be named after mountains. Of the three, the Aconcagua is the largest (And is, in fact, the largest mountain in the southern hemisphere).