ENGINE EXPLOSIONS
Though the scientific reality of fusion engines prevents them from exploding, the dramatic effect of such an expensive piece of machinery blowing up in a huge ball of fire is so appealing
to the majority of BattleTech players that this rule was created to satisfy the common desire for a good explosion.
The fusion engines that power ’Mechs and certain vehicles are well protected from damage. Designed to operate under heavy fire, they can withstand direct hits from enemy weapons. Fail-safe devices and the basic physics of magnetic plasma confinement present in all fusion engines prevent them from exploding when damaged; instead, the engine shuts down immediately when catastrophic damage occurs (as described in detail on pages 36-37 of
TechManual). However, secondary effects may sometimes create massive explosions.
The fusion engine of a ‘Mech may explode any time four or more of its slots are destroyed in the same phase of a turn, usually when the center torso location is destroyed (also destroying the equipment contained therein).
When the fusion engine of a ‘Mech takes four or more critical hits in the same phase, roll 2D6. On a result of 10 or higher, the engine explodes. In the case of fusion-powered Combat and Support Vehicles and aerospace fighters, the engine explodes on a 2D6 result of 12 after an engine critical hit.
The explosion destroys the unit and all other units in the same hex, and also starts a fire in the hex, regardless of the terrain (see p. 43). Any units in adjacent hexes take damage equal to the engine’s rating divided by 10 (rounded to the nearest whole number; round .5 down). Units 2 hexes away take damage equal to the engine’s rating divided by 20. Units 3 hexes away take damage equal to the engine’s rating divided by 40. Divide this damage into 5-point Damage Value groupings and randomly determine each location; determine the direction of the attack from the direction of the hex where the engine exploded.
Area-Effect Weapon: An engine explosion is treated as an area-effect weapon, and so all rules that apply to such weapons also apply to an engine explosion.
Buildings, Levels (Hills) and Mobile Structures): Use the rules for Buildings, Levels (Hills) and Mobile Structures as they interact with artillery when determining the outcome of an engine explosion’s interaction with such terrain features (see p. 184).
Water: Use the rules for Area Effect Weapons against buildings (see p. 172, TW) when resolving the damage from an exploding engine if the target is in a water hex. If the target is not in a water hex and an adjacent hex is a water hex, no damage is applied to completely submerged targets in that adjacent hex.
Woods: Woods hexes provide no protection against damage from engine explosions, even if the Woods Cover (see p. 84) rules are in use.
Tactical Operations pages 77 & 78