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Prop Strike engine potential Problems

S

Sibirsky

Well Known Member
I have long had this question , I couldn't help but ask ,
I have a Prop strike engine installed in my RV9A, it is overhauled to factory new limits , has 2800 hours TT and about 100 SMOH ,
what are the problems I can potentially , possibly face in the future ?
I am leaning towards getting a brand new engine once paint is done .
Thank you
 
Assuming that the appropriate metal parts were magna-fluxed during the overhaul and assuming the overhaul shop performed all prop strike inspection points/replacements and assuming the overhaul was after the prop strike, you should expect no issues that you wouldn't also have with a non prop strike engine. Time has shown that magnetic penetration testing will show any defects created by the prop strike event. Lots of prop strikes with tested parts placed back in service and VERY FEW broken cranks. While I have no data to back it up, I would expect as many or more broken cranks from manufacturing defects as from prop strikes, assuming those cranks were tested before being placed back in service. New is not always a panacea either; ask the guys who bought XP-400's.

I purchased a prop strike core for my 10. I have all confidence that the testing and re-condition that ASI did will net me a crankshaft just as reliable as a new one. Others will certainly disagree, so you'll need more research than just responses to this thread.

Larry
 
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If your engine was indeed overhauled to "factory new limits" by a reputable person or facility AND all the supporting paperwork is in order, then you should certainly have no reason to believe your engine will not go the distance. I have seen too many so called overhauls that have a logbook entry stating as such, but in reality there is no paper trail to prove the claim. A proper engine overhaul should have virtually every part accounted for, including part #'s, serial #'s where applicable, 8130's, yellow tags and whatever else is necessary to determine what's inside your engine. If the engine was overhauled by a repair station, they may reference a W/O #, if so you should contact them, and they are required to provide you with all the details of the overhaul. In that case I would obtain hard copys of these documents. Yes, new is not necessarily better, but it's origin is unquestionable. If indeed your engine passes muster, then spend the money on something else, avionics are always fun!
 
Sibirsky said:
I have a Prop strike engine installed in my RV9A, it is overhauled to factory new limits , has 2800 hours TT and about 100 SMOH ,
Click to expand...

Context can be difficult with written word at times.....

The answer depends on whether the overhaul was done before or after the prop strike.

If before, there could be numerous different monsters hiding inside.
If the overhaul was done after, and it was done properly, I would have no problem using it the same way I would a new engine.
 
Personally, if it was me, I would sell the engine and buy a new one.
(if I couldn't afford a new engine I'd at least replace the crank and associated hardware)
I fly a bunch of cross country with wife and some IFR sprinkled in, a prop strike engine ain't gonna cut it for my peace of mind.
 
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Many many many pilots fly thousands and thousands of hours on prop struck overhauled engines. If the parts were inspected and mandatory parts replaced it's the same as a regular overhaul. During a new build or overhaul parts are inspected and new parts (bearings, bolts, etc.) are installed. The real question is not if a prop stuck engine is just as good, but was the overhaul done right, and this would apply to a non prop struck engine, too.
 
When you say prop strike, what did it hit. I understand that now if a running engine's blade hits tall grass it's considered a prop strike.
 
Prop Strike

A story from long ago: almost new Twin Commanche landed gear up. I did the airframe repairs. Shop manager dialed the cranks and after removing the mags looked in the accessory case. No other work on engines. At the time there was no requirement other than dialing the crank.
I got my multi rating in that airplane and flew it a couple hundred hours. It recently became inactive in FL.
A more recent story: 135 operator had a serious prop strike on Twin Cessna. Locked the airplane in a hangar while the prop was being overhauled. NO engine inspection.
When one rents an airplane they have no idea of the damage history of the airplane.
I will close with this: If I had to chose between a prop strike homebuilt and a Boeing I will take the homebuilt.
 
jrs14855 said:
...A more recent story: 135 operator had a serious prop strike on Twin Cessna. Locked the airplane in a hangar while the prop was being overhauled. NO engine inspection.
...
I will close with this: If I had to chose between a prop strike homebuilt and a Boeing I will take the homebuilt.
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I had to do an emergency landing at night when one of my helicopter engines blew up in flight less than an hour after the Lead Mechanic was told by the DOM in another state that it was ok to fly with that grinding noise at start up.

At another company, after trying to get management to do the right thing for over a year, I was "retired" from that job after whistleblowing to the FAA because that carrier continued pencil whipping inspections (BTW, thanks for the awesome settlement money :) .

So I concur that if it was overhauled outside of the 121/135 world I would be fine with it.
 
135

Sometimes a FAA ramp check at 0700 can be the start of a wonderful day. I finished a scheduled freight run a couple hundred feet from the local FSDO office. Inspector showed up and very politely asked to look at the airplane. I showed him all the paperwork and he started looking the airplane over inside. The pilots shoulder strap looked like a rat had chewed half way thru it. The Fed asked me "what do you think I should do about this?" My reply was I think you should ground the airplane. Which he did. The phone call I made to my boss was one of the most rewarding phone calls I have ever made. It was my get even time and not a thing the boss could do about it.
A couple of other gems: Private pilot flying a scheduled freight run in a Cherokee 6. Twin turbine engine blew up near the airport and scattered parts all over the "hood". Company tried to get away with not reporting the event. Event was on the front page of big city newspaper.
I had an engine blow up in a Twin Cessna. I made a personal visit to the local FSDO. They would not let me in the office because I did not have an appointment, came outside and talked to me. Stated they were not interested in the event. Few weeks later I got a phone call from the same FSDO wanting to know why I had not reported the incident.
AS THE PROP TURNS. I have enough material for at least two books. I have had an unusually high number of contacts with the FAA. Most have been very positive. The few bad ones have been very ugly.
One of the funniest was a routine FAA line check, Atlantic City weather busted the forecast, was up and down at and below mins. Fed says "I sure need to get home tonight. I'm going in the back to check on the Flight Attendants and I won't be back".
 
It also depends on what the e of prop hit. Wood and composite will come apart before transmitting lots of destructive energy into the engine.
 
jrs14855 said:
Sometimes a FAA ramp check at 0700 can be the start of a wonderful day. I finished a scheduled freight run a couple hundred feet from the local FSDO office. Inspector showed up and very politely asked to look at the airplane. I showed him all the paperwork and he started looking the airplane over inside. The pilots shoulder strap looked like a rat had chewed half way thru it. The Fed asked me "what do you think I should do about this?" My reply was I think you should ground the airplane. Which he did. The phone call I made to my boss was one of the most rewarding phone calls I have ever made. It was my get even time and not a thing the boss could do about it.
A couple of other gems: Private pilot flying a scheduled freight run in a Cherokee 6. Twin turbine engine blew up near the airport and scattered parts all over the "hood". Company tried to get away with not reporting the event. Event was on the front page of big city newspaper.
I had an engine blow up in a Twin Cessna. I made a personal visit to the local FSDO. They would not let me in the office because I did not have an appointment, came outside and talked to me. Stated they were not interested in the event. Few weeks later I got a phone call from the same FSDO wanting to know why I had not reported the incident.
AS THE PROP TURNS. I have enough material for at least two books. I have had an unusually high number of contacts with the FAA. Most have been very positive. The few bad ones have been very ugly.
One of the funniest was a routine FAA line check, Atlantic City weather busted the forecast, was up and down at and below mins. Fed says "I sure need to get home tonight. I'm going in the back to check on the Flight Attendants and I won't be back".
Click to expand...

I wish they would have done ramp checks when I was flying for a living. Hopefully the Boeing 737 issue will shine a light on FAA Inspectors in bed with the companies they should be checking on.
 
Get Writing

"AS THE PROP TURNS. I have enough material for at least two books."

Better write those books. Just a little every day and they will be done.

I can see a new roller cam IO 390 in your RV, lots of fuel and plenty left over for a very fine retirement. :D

Let this forum know when the first copy is available.
 
He should write a book !! I'd write one but my last job gave me so much money after I signed an NDA that I don't want to get sued and have to return the money :D:D:D:D
 
Sibirsky said:
I have long had this question , I couldn't help but ask ,
I have a Prop strike engine installed in my RV9A, it is overhauled to factory new limits , has 2800 hours TT and about 100 SMOH ,
what are the problems I can potentially , possibly face in the future ?
I am leaning towards getting a brand new engine once paint is done .
Thank you
Click to expand...

I agree with the statement about "who did the overhaul". If the engine was overhauled to factory new limits by a reputable engine shop than every component was inspected to ensure it meet "new" limits not just overhaul limits. If this in fact accurate, how is this engine suspect?

I know of at least one RV that suffered crank failure in the first 25 hours of a factory new engine.
 
sahrens said:
... If the engine was overhauled to factory new limits by a reputable engine shop than every component was inspected to ensure it meet "new" limits not just overhaul limits. If this in fact accurate, how is this engine suspect?
Click to expand...

Need to be cautious here. There are no "factory limits" on the size of microscopic cracks in a crankshaft. The key is a reputable shop that will do reputable work. Every crankshaft should have magnaflux testing before being reinstalled at overhaul. However, this is not outlined in an overhaul manual and is not required (it is required for an official prop strike inspection though). Overhauling to factory limits, just means that the journals are of a certain size tolerance and a couple of other dimensions.

Be careful in what you take comfort in. Prop strike damage to a crank is usually microscopic and can only be detected by magnetic particle inspection. A "factory limits" crank can have several microscopic stress cracks and will be just waiting to fail. The limits are most wear limits and are really more about longevity.

Larry
 
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My 8 has a rebuilt prop strike donk, I've done 550 hrs behind it and runs perfect, I wouldn't touch it, leave well alone I say:)
 
Well in that case I went and checked the exact hrs, 559.7, I'm flying my RV tomorrow, if I'm not back here to check in I guess you may well be correct:D
 
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