Well, for the fireball, try the effectpack from Maxpain, providided with the ORCS Zil-131
ftp://www.gamezone.cz:8021/ofpd/unofaddons2/zil10.rar
If the link doesn't work, remove the :8021
When you've installed at least the Effects.pbo from the rar file, put a plane in the editor, and put this in its init field - [This] exec "\Effects\planevzriv\planevzriv.sqs"
When the unit gets over 0.7 damage, watch what happens.
Other effects -
[This] exec "\Effects\vzriv\vzriv.sqs" <----- General explosion
[This] exec "\Effects\vertolvzriv\vertolvzriv.sqs" <----- Midair explosion (Maybe only for choppers?)
[This] exec "\Effects\Planesled.sqs" <----- Fuel-loss/smoke for aircraft?