What would bend prop blades forward?

[poadeleted3]

What could cause this kind of damage? Some background, this is part of an accident report from a Skyhawk that crashed, reasons unknown so far, while on pipeline patrol. This damage description just seems a little unusual to me. It's like the airplane was going backwards.

"One propeller blade was bent approximately 90 degrees forward at mid-span. From mid-span outward, the non-cambered side exhibited polishing. There was no leading edge gouging or chord-wise scratching. The other blade was bent slightly forward at mid-span towards the cambered side. There was no leading edge gouging or chord-wise scratching."

 

[Henning]

What could cause this kind of damage? Some background, this is part of an accident report from a Skyhawk that crashed, reasons unknown so far, while on pipeline patrol. This damage description just seems a little unusual to me. It's like the airplane was going backwards.

"One propeller blade was bent approximately 90 degrees forward at mid-span. From mid-span outward, the non-cambered side exhibited polishing. There was no leading edge gouging or chord-wise scratching. The other blade was bent slightly forward at mid-span towards the cambered side. There was no leading edge gouging or chord-wise scratching."

That meant the engine was making power when it hit the ground. When you sink a prop into the ground with a load of power, the ground doesnt compress, this coupled with the fact that the rest of the aircraft is typically decellerating VERY quickly, causes the prop blades to bend themselves forward by "climbing" forward on their pitch. If the all the blades are bent backwards, it means that the engine was turning, but not producing power. Next thing you do is check the fuel sumps, probably dry, occasionally not. One or no (or 2 of 3...) bent back means the engine wasn't turning when it went in.

EDIT: Just as I posted I read the bottom closely, soft mud. I'd like to read a bit more and know what the conditions surrounding the damage. It sounds like it was a soft/rough field nose drop into some real boggy ground, probably Indiana or Illinois farm country, some where predominantly alluvial with a low sand/ rock content in the ground.

 

[John J]

Henning


Thank you for your post I do remember that when the prop strikes the ground under power it is "pulling" and the blades will always bend toward the front. "S" bending and scratches on the back side tell there was power on the prop. I do remember so well when I was on a search mission to find one of my flying buddies dad who had flown into a side of a mountain trying to scud run. Yes there is so much to learn.


John J