When attacking Vehicles, Knights, Titans, Aircraft or Fortification, instead of making a wound roll in the attack sequence at Step 2, you instead must roll to penetrate. First, check visibility to determine if you are hitting the Vehicle's Front, Side or Rear (if unsure it's best to stoop down and check from behind the attacking model). If you cannot determine which facing, make your attack against the unit's Front Armour Value (FA).
To determine if you penetrate the Vehicle, Knight, Aircraft or Fortification, roll a dice and add the attacking weapon's Strength. If the total is equal to or higher than the Vehicle, Knight, Aircraft or FortificationsArmour Value (FA / SA / RA) characteristic, you score a penetrating hit and roll on the Vehicle damage chart (see 10.1). If you do not equal or exceed the vehicle's Armour Value Characteristic, the attack fails, and the attack sequence ends.
Vehicles, Knights, Aircraft, Fortifications do not have Armour Saves but they may still make any Cover Saves or Invulnerable saves they may qualify for. These saves are made after determining if a hit Penetrates but before rolling on the Vehicle Damage chart (see 10.1) to determine the result of the Penetrating hit.