1 Prof. Jones: I didn't know you could fly a plane, Junior.
2 Monty: You'd be surprised at what I can do if I try, dad.
3 GM: Errr... Your default skill in Piloting is only 6.
4 Monty: Like crash landing. I can do that.

2012-02-10 Rerun commentary: Default skill levels in roleplaying games are pretty much what they sound like: the skill level you have to roll against if you have no training whatsoever in the skill.

In GURPS, default skill use assumes that you are from a culture where the skill is actually known and used by some people, just not yourself. So you and I would get a default roll to try to land a plane safely*, because we know what a plane is, and we have a (very) rough idea of what might be involved in trying to land one.

If you involve time travel, then someone from the 17th century would not get a default roll to try to land a plane, because up until a week ago they'd never even seen or conceived of a plane before.

So next time you're on a flight and the cabin crew put out a desperate call for someone who can land a plane, put your hand up. You have a much better chance than any 17th century time travellers who might happen to be on board.

* This assumes you don't actually know how to land a plane. Anyone who's taken flying lessons and writes in to tell me, "Actually, I do know how to land a plane," will be summarily chimp-slapped.