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Prop Strike Engine Has Run 1200 Hours

JackW794

Member
I'm considering purchasing a Lycoming IO-360 that had a prop strike in 2004 and has run 1200 hours since then without incident. The engine log has the following statement, "AD2004-10-14C C/W after prop strike N/A by condition."

I'm not sure what that statement means, and it makes me a bit wary to use such an engine without a tear-down inspection. Or perhaps since the engine has run so long after a prop strike, the engine is probably reliable since there hasn't been a problem since then.

Any advice?
 
Crankshaft

Angle valve or parallel valve?? At least four different cranks for parallel valve.
Thin flange with lightening holes
This flange without lightening holes
Heavy flange (mostly aerobatic airplanes
Solid front main bearing area will not support constant speed prop.
At a minimum I would want to check the flange runout and thickness
 
I'm thinking I would ask seller to produce a copy of that bulletin for clarification.
If I were considering that engine, I'd assume it was a core, that it would have to go for prop strike disassembly & inspection per SB533C, that it complied with SSP-1776-5, and that it was probably going to be expensive, might as well be a total overhaul.

But, my view is influenced by the engine I'm waiting to be delivered as I type this... coming back from a prop strike repair, done by a reputable shop... & it was expensive...
 
Prop Strike

The engine is a C1C that come off a Piper Arrow. Other than that, I don't know any particulars about the engine. There is no record of doing a flange runout.
 
Reading that log book entry raises red flags for me. A prop strike requires a compliance tear down and inspection by a qualified person. Sounds like that was not done, just a visual inspection of whatever was done and a log book entry that there was no visible exterior damage. Just my humble opinion.
 
AD

Here is the AD.

http://www.yeeles.com/Reference/AD/Lycoming/2004-10-14.pdf

Perhaps they meant complied with after prop strike not required by condition of the propeller. The AD defines a prop strike as

Definition of Propeller Strike

(i) For the purposes of this AD, a propeller strike is defined as follows:
(1) Any incident, whether or not the engine is operating, that requires repair to the propeller other
than minor dressing of the blades.
(2) Any incident during engine operation in which the propeller impacts a solid object that
causes a drop in revolutions per minute (RPM) and also requires structural repair of the propeller
(incidents requiring only paint touch-up are not included). This is not restricted to propeller strikes
against the ground.
(3) A sudden RPM drop while impacting water, tall grass, or similar yielding medium, where
propeller damage is not normally incurred.

(j) The preceding definitions include situations where an aircraft is stationary and the landing
gear collapses causing one or more blades to be substantially bent, or where a hanger door (or other
object) strikes the propeller blade. These cases should be handled as sudden stoppages because of
potentially severe side loading on the crankshaft flange, front bearing, and seal.

You would need the details of the actual strike, perhaps there was only minor dressing of the propeller (i 1) and there was no RPM drop and (j) did not apply.
 
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I'm curious what defect or abnormal occurrence caused that sign-out. Hit a sparrow or other small bird is a vastly different prop strike compared to a sudden stoppage on a concrete block. Sometimes the only evidence is a little red stain on the propeller's paint or some feathers stuck to a spinner screw.
 
the C/W seems to me that the AD was complied with, the N/A throws the red flags. Not Airworthy?
 
Prop Strike, Walk Away!

It will be fine.....Till it's Not! OP doesn't state hours before prop strike. 1200 since prop strike. For arguments sake lets say it was half life 1000 hours, that puts this engine just over TBO. IO-360C1C is 200hp, The cost of rebuilding this engine, your not too far off from a new one from Vans. Walk Away!
 
1200 hours since the prop strike is a likely indicator that it's mostly OK - but it still a high time motor with a questionable background.

Core value.
 
Prop Strike

I asked the seller about the engine "prop strike" notation. He said a lot of engine logs have some similar wording about the AD being complied with (C/W) because of the condition that no prop strike occurred (N/A). This AD was in a list of a few other ADs that needed compliance at the same time. I guess the ADs were issued during the same time period.

So, does this explanation make sense to you that are A&Ps or have some knowledge of how AD compliances are addressed?
 
I asked the seller about the engine "prop strike" notation. He said a lot of engine logs have some similar wording about the AD being complied with (C/W) because of the condition that no prop strike occurred (N/A). This AD was in a list of a few other ADs that needed compliance at the same time. I guess the ADs were issued during the same time period.

So, does this explanation make sense to you that are A&Ps or have some knowledge of how AD compliances are addressed?

So he’s saying no prop strike occurred thus the AD was not applicable? The verbiage used by whoever wrote the log entry is very strange if that’s the case, particularly the words “after prop strike.”
 
The Lycoming Mandatory Sudden Stoppage SB and AD has the criteria for defining a prop strike. A previous post listed them. An aircraft that has been run through tall grass can meet the criteria for a Sudden Stoppage requiring inspection.
It's not cheap so right away, there is the impulse to ignore both using the rationalization "it's Experimental Amateur built" so SBs & ADs do not apply. FAA wise this is true.

Start off by asking your self this question:
What is the difference between a Certified engine failure and an Experimental engine failure?
Ans: NOTHING the outcome is identical. Experimental's do not get Mulligans!!!!

Has the Builder and holder of the Repairman's Certificate been signing the Condition Inspections? This has a completely different Risk/Liability picture than a none builder A&P. The builder/repairman signs it off and assumes all personal risk for his decisions. A surviving spouse that is getting it all anyway, isn't going to sue just for kicks.

I have had aircraft show up at my shop for Condition Inspections with this very issue. They were turned away, I will not touch them. There are a number of very good reasons why Lycoming issued Mandatory inspection for this. They have decades of failure and engineering data supporting their position. There is no way to convince a jury of my piers that I know better.
This bring you to the next question:
Who are you going to get to sign it off?

After 1200 hrs it is easy to decide your pretty sure it's OK. There is a very good series of TV commercials with humorous analogies for the short comings of "pretty sure".

My opinion is like stated previously. It's got 1200 hrs on it with a compromised history. View the engine as nothing more than a a core for overhaul or replacement. Research the cost and make an offer accordingly.
 
When I had my prop strike it left a very small Nick and a propeller and I was thinking of just letting it go. I talked to my mechanic and he showed me a picture of a prop that had less damage than mine. The owner refused to rebuild the engine, the crank was cracked and some time later split and caused the front two cylinders along with the prop to leave the aircraft. Unfortunately without survivors. Could be a wives tale but who knows?
 
Maybe a rush to judgement

So if you pick up a rock or two running up and they hit the prop, is that a prop strike? By definition it is. Say the damage requires minor dressing of the propeller and the A&P dressing the propeller feels compelled to write down why the dressing was required.

It is possible the mechanic wrote down that something hit the prop but by condition it does not constitute a tear down analysis.

Again the AD states

(i) For the purposes of this AD, a propeller strike is defined as follows:
(1) Any incident, whether or not the engine is operating, that requires repair to the propeller other than minor dressing of the blades.

Without knowing the history of the maintenance requirement it is not possible to know if the engine is airworthy. Certainly the logbook entry could be clearer.
 
I'm considering purchasing a Lycoming IO-360 that had a prop strike in 2004 and has run 1200 hours since then without incident. The engine log has the following statement, "AD2004-10-14C C/W after prop strike N/A by condition."

I'm not sure what that statement means, and it makes me a bit wary to use such an engine without a tear-down inspection. Or perhaps since the engine has run so long after a prop strike, the engine is probably reliable since there hasn't been a problem since then.

Any advice?

My read of that statement is that they complied with it, but they further state that it was not applicable. I would have to assume from this that a tear down was not completed. With a proper procedure, making a prop strike engine reliable again is very doable. However, regardless of the hours since the strike, I am not sure that I would fly behind that engine without the tear down and proper inspection.

Larry
 
A friend who was an Automotive Engineer and was a member of the original design team for several OEM engines, explained the widely varying results from "prop strikes". It is all about timing. If the "impediment to rotation" :D occurred just as a cylinder fired, the "loads" on the propeller "go to Valhallla".

Because fractures can occur "deep", i.e. below the depth range of magnaflux inspection machines, the only way to definitively check the crank for "fracture planes" is by commercial X-ray.

FWIW
 
Prop Strike

The annual inspection was signed off by an AP. I take his sign off to mean that the prop strike notation was either a minor propeller nick or there was no prop strike at all.
 
The annual inspection was signed off by an AP. I take his sign off to mean that the prop strike notation was either a minor propeller nick or there was no prop strike at all.

And with that, looks like you've resolved your course of action.
You will have time to do a thorough external examination (like prop flange run out measurement) as you convert the engine for RV fitment. Good luck.
 
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I asked the seller about the engine "prop strike" notation. He said a lot of engine logs have some similar wording about the AD being complied with (C/W) because of the condition that no prop strike occurred (N/A). This AD was in a list of a few other ADs that needed compliance at the same time. I guess the ADs were issued during the same time period.

So, does this explanation make sense to you that are A&Ps or have some knowledge of how AD compliances are addressed?

Yes, this explanation makes sense. I wouldn't have done it (I'm an IA), but I can see where someone might have felt it was necessary to address the AD. I guess I would probably call the mechanic and ask him to verify that was his intent.
 
Well.... The engine is off a Piper Arrow. What's the most typical prop-strike damage to a retractable airplane? Core value.

-Marc
 
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