Crush a Flyer

"Crush is a focused witchfire power with a range of 18". Roll
2D6. The target model suffers a hit with a Strength equal to the
result (a score of an I I or l2 wounds automatically or, in the
case of a vehicle, causes an automatic penetrating hit) wlth an
AP equal to the result of a separate D5 roll."

"WITCHFIRE
Witchfire powers manifested during the Psyker's Shooting
phase instead of firing a weapon. Witchfire powers are often
referred to as psychic shooting attacks. Manifesting witchfire
counts as firing an Assault weapon (unless otherwise noted).
A witchfire power must roll To Hit, unless it is a Blast or Large
Blast, in which case it scatters as normal, or is a Template weapon,
which hits automatically. Saves can be taken against'S7'ounds
from witchfire in the same way as for any other shooting attack.
The Psyker must be able to see the target unit (or target point),
cannot be locked in combat, must not have Run in the Shooting
phase and must shoot at the same target as his unit, if he wishes
to manifest witchfire. In the same way, if a Psyker targets a unit
with witchfire, then he and his unit can only charge that target
in the ensuing Assault phase. Note that, as witchfire is a Shooting
affack, a Psyker embarked on a vehicle can target an enemy
outside that vehicle by using a Fire Point.
Even if a Psyker has a special rule allowing him to manifest
more than one psychic power per turn, he can manifest only
one witchfire power
-
regardless of its subtype (see below).
However, if he can shoot more than one ranged weapon per
turn, he can use a different witchfire power in place of each
(assuming he has enough warp Charge).

There are several different sub-types of witchfire, each applying
slightly different targeting restrictions. If the witchfire does not
list a subtype, or simply describes itself a psychic shooting
attack, use the rules given above to resolve it. If it has one of the
following subtypes, use the rules for that subtype."

Focussed Witchfire
Some witch fire powers can pick out models in an enemy
unit
-
these are called focused witchfire powers. They follow
all the normal rules for witchfire, but you can choose the
specific model in the target unit that you want the power to
affect. This isn't guaranteed, however, as such powers require
great concentration whlch can easily be broken. Accordingly,
when the Psychic test is taken for focused witchfire, pay close
attention to the actual number rolled. If the total is 5 or less and
the Psychic test is passed, then the power is resolved against the
model you chose. If the total is greater than 5 and the Psychic
test is passed, randomly select a different model in the same
unit for the power to be resolved against.