The Sky Fortress Pack Add-on for Just Cause 3 has 7 achievements.
Defeat the "Old Friend" (Boss at the end of "Taking Control").
Earn at least 1 Gear in all Challenges of the Sky Fortress Expansion.
Defeat 1 of each Drone type.
Use the Barrel Roll to evade 10 incoming missiles.
Use the Bavarium Wingsuit to take off from water.
Beat the last mission of the Sky Fortress Expansion and complete the story arc.
Earn 5 Gears in all Challenges of the Sky Fortress Expansion.