I don't know about the Aluminum Overcast engines but the Nine O Nine hit
a runway sign (one of those big lighted ones made of heavy aluminum) at
Long Beach a couple of years ago with the #2 prop putting a little ding
in the prop. They dressed the prop and checked the crankshaft runout
and the FAA blessed 'em to keep flying...no teardown. Granted, the gear
collapse did more damage to the prop, but when the 909 hit she was still
at a pretty good power setting.

I'm no mechanic, but looking at the video I would think that the weight of
the plane coming down on those prop blades, imparting such a bending force
on the prop hubs, would require a tear down.

Not to mention the cowlings being crushed into the bottom row of cylinders,
and the exhaust system being broken off.

Did 909's engine actually stop when it hit the sign, or did it keep running?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"