"We've gotta take back the city! We have to take things into our own hands!"
― Ustio civilian

"Diapason" is the sixth campaign mission in Ace Combat Zero: The Belkan War. The player must liberate Directus, the capital city of Ustio, and win back the country's independence. The player must also shoot down the Belkan Air Force ace squadron Gelb Team.


Preparations to liberate Directus are now complete. I will now brief you on the Ustio 6th Air Division's role in regaining control of the capital. Directus is divided into five administrative wards centering on the River Crescere. Powerful weapons have been place in each ward, comprising the Belkan army's Ustio-branch headquarters. This battle will determinate our fate, as the annihilation of all enemy forces will mean liberation for the nation of Ustio. The enemy forces are primarily comprised of ground troops, but we have received information that, while not yet confirmed, there is also a squadron of hi-tech enemy fighters. Your orders are to destroy the Belkan forces and liberate Directus. We can't afford to lose.



Directus is separated into five different areas, each defended by many Belkan ground forces and a few bandits. The player's main objective is to destroy all AA GUNs, SAMs, and APCs marked as TGT. As the mission progresses, a group of tanks will convert to friendly as civilians retake the town.

Partway through the mission, a Belkan A-10A will engage a group of Allied ground units. If the player shoots down the A-10A before it destroys the ground units, the player's Ace Style gauge will receive a boost towards Knight.[1]

Mission Update

After the player liberates the city, Gelb Team will enter the airspace. They fly two powerful and fast Su-37 Terminators, each with the capability to fire missiles backwards. The player must shoot both of them down to complete the mission.

Enemy Lists

The following enemy lists are taken from the Ace Combat Zero: The Belkan War Perfect Guide Book.[1]

Standard Units

Section Unit Points Count Difficulty Other Notes
Initial Icon-AirEnemy.svg Typhoon 700 1
Icon-AirEnemy.svg MiG-29A 400 2
Icon-AirEnemy.svg MiG-29A 320 2 Very Easy/Easy
400 2 Normal/Hard
480 2 Expert/Ace
Icon-AirEnemy.svg A-10A 360 1 [note 1]
Icon-AirNeutral.svg CH-47 500 1 [note 2]
Icon-GroundTGT.svg SAM 120 9
Icon-GroundTGT.svg AA GUN 100 6
Icon-GroundTGT.svg APC 100 3
Icon-GroundEnemy.svg TANK 150 3 [note 3]
Icon-GroundEnemy.svg SAM 120 1
Icon-GroundEnemy.svg AA GUN 100 3
Icon-GroundNeutral.svg TENT M 200 19
Mission Update Icon-AirTGT.svg Su-37 "Gelb" 2770 2

Special Units

AR # Unit Points Campaign
Ace Style Notes
Icon-AirEnemy.svg 046 F-15C "Ibis" 960 Very Easy Mercenary
Icon-AirEnemy.svg 047 EA-18G "Wolkenmeer" 1140 Very Easy Soldier [note 4]
Icon-AirEnemy.svg 048 F-14D "Wildgans" 1000 Very Easy Knight
Icon-AirEnemy.svg 049 F-15 S/MTD "Wuerger" 1610 Ace

S Rank

Earning an S rank on this mission requires clearing it in 10 minutes or less.[1] Since the timer does not reset in the Mission Update, the player has only 10 minutes to destroy every TGT and Gelb Team. It is recommended to use bombs or XAGMs to quickly liberate Directus, allowing for plenty of time to shoot down Gelb.


Belka's Ustio-branch headquarters has fallen. Directus has been liberated. I just received a vintage bottle of Chateau Boloise for the Galm Team. It's a hard-to-find Cabernet. Perfect, I'd say, for celebrating an occasion such as this.


  1. This A-10A will attack two of the player's friendly ground units. If the player shoots down the A-10A before the units are destroyed, the player's Ace Style gauge will receive a boost towards Knight.
  2. This CH-47 spawns after the player destroys every TGT in the two southern-most sectors, and at least one in either of the middle two sectors.
  3. These three TANKs turn into friendly units after the player destroys all TGTs in three of the five districts.
  4. "Wolkenmeer" spawns when the player destroys all TGTs in any three sectors.