hi yall

i have a 601xlb w/0235 lycoming w/wooden prop i landed in tall 

grass.engin did not stop.a small pc 8" LONG By 1/2" wide

broke out of the trailing edge of prop.i replaced with a warp drove

ground adjustable and flew it back to my home ap have flown

15 hrs since .i dont think this constitutes a prop strike.

what say you.

thanks for your input


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It's a prop strike..... that said, it doesn't sound too severe and the likelihood is that the engine is OK.  You could have an engine shop check the run out for peace of mind.


Just curious,,  do AD notes apply to Lycomings and Continenals installed on experimental acft??

yes its a prop strike but not a metal prop/sudden stoppage/under power. That one is a no brainer. you can go in the Lyc manual and see what it says and do exactly that which can probably be interpreted to mean a complete teardown which many engine shops will say has to be done.. but they got CYA to worry about. or you can go the common sense/experimental category/you're the man route...its a wooden prop with an 8" sliver knocked off the trailing edge. you could knock a ladder over against it in the shop and do that. would you do a teardown for that?

if you wanta ease your mind just put a dial indicator on the flange and check the runout as already mentioned but personally i would do it myself.  if there's any there it likely existed before the sliver broke out.

you will get answers all over the map on this. its your baby


If you want to check it yourself and don't have the tools to check the run out. Here is a procedure they taught at one of the classes I went to. It came from FAA Advisory Circular AC 43.13-1B which you can probably reference on line. It also referenced a drawing for the procedure.

Here is the procedure from the AC:

1. Chock the aircraft so it cannot be moved.

2. Remove one plug on each cylinder making the prop easy and safe to turn.

3. Rotate one of the blades so it is pointing down.

4. place a solid object (e.g. a heavy wooden block that is at least a couple of inches higher off of the ground than the distance between the propeller tip and the ground) next to the propeller tip so that it just touches.

Rotate the propeller slowly to see if the next blade "tracks" through the same point (touches the block).Each blade track should be within 1/16" inch (plus or minus) from the opposite blades track.

5. If the propeller is out of track, it may be due to one or more propeller blades being bent, a bent propeller flange, or propeller mounting bolts that are over or under torqued.An out of track propeller will cause vibration and stress to the air-frame and engine, and may cause premature propeller failure.

Under number # 4 above they also indicated you could use a pointer/indicator attached to the cowling itself, instead of the wooden block.


You can do what Jim says and isolate it down to the items listed in #5 but the only way that I know of to find out if the flange is bent is a dial indicator. Theoretically, it could track perfectly against the block and the flange still be bent. It just didn't show up cause the prop happened to be out of track just right to cover the bent flange. Yeah, I know not likely but possible. The dial indicator will eliminate any doubt.

You must have missed it...Bent flange is also one of the items under #5. 

well, actually, nosir,  I didn't miss it. #5 narrows it down to 3 possibilities. There is no way that I can see to determine which of the 3 possibilities is the actual problem using the block method. It could be any one or all of the 3. I believe the OP is concerned solely about a bent flange. Again, the only way that I know to determine if the flange is bent is by dial indicator. The blocks/prop  won't reliably tell us that.

The block check was only a way to do it if he wanted to check it his self and didn't have a dial indicator. Since he already eliminated the prop blades by installing new ones, and of course re-torquing eliminated the possible over/under torque, then a bent flange is the only thing left. If it still  checked bad he would want it checked further at that point anyway.

Also remember that this is a quick easy check from an FAA AC that is not meant to repair or isolate a problem, but just tell you there is a problem.

Well,  actually a perfect block check doesn't necessarily mean the flange is not bent as I noted a couple replies back. The prop being used as the measure is still a variable...new blades and fresh torque do not eliminate those as variables. One variable can mask another as has been proven many many x in the past and as I mentioned in the same post a couple replies back... Murphy's Law.  If we dial the flange there are no variables in between the measure point and the result. I wouldn't rely on a block check to check for a bent flange, nosir. Only value I can see in the block check is to first dial a suspect flange and if it dials straight then do the block check to determine if the prop is tracking. Regardless the FAA AC

How bout this, Jim...you use the blocks; I'm gonna use the dial indicator so I'll know exactly what I got. Yessir...

Since I've never had a prop strike, I'm not sure what checks I would do first. I would probably use a dial indicator at least once, since I used one at least weekly in a previous job. The block check was presented in an aircraft maintenance course, and I wasn't aware of any of the faults you pointed out associated with the procedure. I now feel compelled to notify the FAA Technical team of these faults they have presented in the AC. Could you please email me your contact information and technical expertise to "depfer at yahoo dot com", in case the technical team requires any addition info or has any questions.  I'm sure I wouldn't have the necessary knowledge to point out the flaws in their procedure. Thanks.

LOL that cracked me up

I'm done here Jim...it's a dead horse. But feel free to PM me if you like


Yes it is a prop strike if the engine was even slowed down by the grass. Almost all manuals and service letters will tell you to do an engine teardown and get the crankshaft Magnetic particle inspected or some other NDT method of inspection. What you also have to look out for is damage to accessory drive gears and components. Magnetos can get their gears cracked, accessory and camshaft drive gears can get cracked teeth. In short, without a teardown inspection most manufacturers would consider you flying on borrowed time. As an experimental you could do a tear down inspection yourself if you have the knowledge and tools. One aspect no one seems to have addressed is how does your insurance company feel about it? If you continue to fly the plane and the crank breaks or some other mishap and they find out about the prop strike what will their view be on any insurance claim?


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