We went through the prestart checklist, and I engaged the starter only
to hear a loud clunk as the first blade went by. He had left the tow
bar on the front gear leg.

I saw a guy do that once.

Hitting the tow bar may not damage the prop, but it sure would damage
whatever the tow bar hit. In the case I witnessed, the prop whipped the tow
bar into the adjacent hangar wall with surprising force. It was only luck
that kept it from hitting a car or bystander.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"