OK...long story short
I dusted off my old INVID INVASION RPG book, went to a friend's place, made them roll up OCC's and dumped buckets of Invid on them

Then I scored a critical hit on one of the pilots.
He opted to make a Tilt Dodge roll (-12% on his skill) to avoid the hit.
This smelt of rancid cheeze!!!
1) I opted against it simply for the fact that it seemed a bogus way of negating a critical hit.
2) On the same topic, don't you have to be engaged in "dog fighting" maneuvers to utilize the special Pilot: Jet/Veritech modifiers listed under the skill description?
In the end, I ruled that only another natural 20 on a defense roll can negate a critical 20 roll. You cannot substitute a skill roll to do it.
I'm wondering if anyone else (more than likely) has encountered this and what they've done. OR perhaps the Palladium Rules Overlords have already answered this topic on another thread.
I'll be checking back for any replies. Thank you all!!!