Prop Strike according to Mike Bush

[AmigOne]

In his article in the December 2013 issue of the EAA magazine, Mike Bush states that, "when properly dealt with in accordance with manufacturer's guidance" he considers "propeller strike a plus not a minus". The reason being all the inspections on the engine components and parts replacement, including most likely a new prop, that will be paid by the insurance plus the fact that "there is no physical evidence that this ever happened (except for paperwork)". He also states that a prop strike does not qualify as damage history because damage history impairs the fair market value of the aircraft while a prop strike actually enhances the value.

What do you think?

Mike Bush was the 2008 National Aviation Maintenance Technician of the Year, his articles can be found at mike.busch@savvyaviator.com

[Cruiser]

From an equipment point of view I agree to the extent the manufacturer's guidance mitigates the risk of hidden/latent defects. The main purpose is to inspect and verify there is no internal damage. 

Assuming there is no additional damage, the tear down and inspection provides a most recent status of the engine condition. Certainly a plus over the airplane offered for sale with a 1000 SMOH completed twenty years ago.

 

The same logic goes for gear ups and other damage history when properly repaired.

[N33GG]

Hypothetically, all things being equal, I have a choice between two aircraft, one without a prop strike, and another with a prop strike...

Hmmm, I really can't imagine thinking to myself: "Hey, good news, that aircraft has a prop strike, now that's a real plus!"

But if it works for you, knock yourself out!

IMHO YMMV etc.

[jetdriven]

Look at the airplane after its done. One has 900 SMOH, one is Zero SMOH or 900 SMOH and zero since IRAN.  I know which one I would buy.  All the damaged parts have been replaced. The insurance compnay's term for this is "betterment".

 

Especially after seeing the condition of midtime engines at prop strike teardown.  Most have serious issues with cam/lifter spalling.

[flyboy0681]

Interesting topic, but don't prop strikes cost us all in terms of higher premiums?

[N33GG]

Look at the airplane after its done. One has 900 SMOH, one is Zero SMOH or 900 SMOH and zero since IRAN. I know which one I would buy. All the damaged parts have been replaced. The insurance compnay's term for this is "betterment".

Especially after seeing the condition of midtime engines at prop strike teardown. Most have serious issues with cam/lifter spalling.

Wait a minute. A prop strike with a 0 SMOH is a whole different deal than zero since IRAN. Different discussion altogether to me...

Part of my problem with all of this is not knowing exactly how well they found everything. I could care less that paperwork is in place and the insurance company is happy. Doesn't make me feel better that I saved a few bucks when the engine starts running bad in the middle of the night...

[jetdriven]

You are right, they are whole different animals, but I think both are better than a 900 SMOH engine that hasnt been apart and looked at. The IRAN engine wont add much value, but it has been reassembled with a lot of new parts, bearings, rings, etc. Its a real plus when it gets a new cam and lifters.

[aaronk25]

You are right, they are whole different animals, but I think both are better than a 900 SMOH engine that hasnt been apart and looked at. The IRAN engine wont add much value, but it has been reassembled with a lot of new parts, bearings, rings, etc. Its a real plus when it gets a new cam and lifters.

That's exactly what happened with mine . Engine got inspected with all new seals (no more oil leaks) overhauled prop governor, new main bearings, crank re-tuned up, new CAM AND LIFTERS, new rings and case gets checked for cracks.

My engine was at 1,400 hours now at 1,600hours and if I decided to sell I would think that the (IRAN inspect and repair as necessary) would be an advantage, maybe not add value but certainly help get it sold as a buyer could be more confident on what they were buying.

Also now since it pretty much got a bottom end overhaul all it might need is cylinders at some point so I'm planning on running 2000 hours from time of IRAN.

[orionflt]

I agree that it can be a double edged sword, if the iran is done properly and the engine has been torn down you will probably end up running the engine well past TBO and only have to worry about the top end. But if they do the minimum required by the AD, then they are just doing a crank run out, changing the dow pin and putting the engine back in service with a sign off of the AD and a new prop. Thankfully the insurance companies know the value of the tear down and inspection because they are willing to pay for it, but if the plane wasn't insured or the owner is trying to pocket some of the insurance money they may do just what is manditory not what is recommended. I am always suspicious of a prop strike and will look closely at the repair write up and who did the repair, if everything was signed off in house by the local mechanic I get a little concerned.

[FlyDave]

If Mike Busch said it I'll defer to NotarPilot

[phecksel]

Am I buying or selling?

 

LOL

[pinerunner]

I think you have to take Busch as being a bit tongue in cheek here. Prop strike is still a bummer. Going all the way to TBO with minimal inspections doesn't work out well either so every cloud has its silver lining. Better not tell that to someone who just had a prop strike.  Of course getting a bunch of fresh new dental work might actually be a good thing, too.

[pinerunner]

In his article in the December 2013 issue of the EAA magazine, Mike Bush states that, "when properly dealt with in accordance with manufacturer's guidance" he considers "propeller strike a plus not a minus". The reason being all the inspections on the engine components and parts replacement, including most likely a new prop, that will be paid by the insurance plus the fact that "there is no physical evidence that this ever happened (except for paperwork)". He also states that a prop strike does not qualify as damage history because damage history impairs the fair market value of the aircraft while a prop strike actually enhances the value.

What do you think?

Mike Bush was the 2008 National Aviation Maintenance Technician of the Year, his articles can be found at mike.busch@savvyaviator.com

Will the insurance usually pay for this? That's the question I ask myself most, under what circumstances will they blow off honoring the insurance policy and leave you paying it all.  The mechanic who does my annuals said the insurance companies are  not as bad I fear since they don't want to get famous for stiffing their customers. Otherwise almost any airplane could be declared not airworthy if you hunt hard enough for an excuse.

 

I bet a prop strike after landing on the beach and you'd be footing the bill on your own.

[aaronk25]

Will the insurance usually pay for this? That's the question I ask myself most, under what circumstances will they blow off honoring the insurance policy and leave you paying it all. The mechanic who does my annuals said the insurance companies are not as bad I fear since they don't want to get famous for stiffing their customers. Otherwise almost any airplane could be declared not airworthy if you hunt hard enough for an excuse.

I bet a prop strike after landing on the beach and you'd be footing the bill on your own.

It's difficult for Insurance companies to not honor a claim. Unless something is specifically forbidden in a policy (such as commercial opps ex.) they can't deny a claim.

The states have government agencies that in a way police insurance companies because states require a license to sell insurance and if they get blacklisted in the state, there done.

Chartis Aerospace (aig) tried pulling some crap and I got MN dept of Commerce involved and 2 days later I got a call from my adjuster mad a hell but, I got what was due to me.

mn.gov/commerce/insurance/

Also insurance is for covering pilots stupid decisions too almost without regard to how foolish it may be as long as your intent wasn't to cause a loss.

If you crash your car going 120mph, the insurance company can't deny the claim because you were breaking the law.

[QuentininVA]

I would appreciate someone clarifying the AD's that describe what exactly is required after a prop strike. 

One service center/sales operation stated that only the crankshaft "run out" be checked, and the crank bolt in the accessory case be replaced. Another certified service facility tells me that total disassembly for an IRAN is required, and that I might as well have the engine rebuilt, for the extra expense and have a zeroed engine.

 

Having seen the statistics that led to the conclusion that a person is better off NOT getting their engine rebuilt - because of serious, and multiple component failures of rebuilds - and reading comments on forums of the many problems experienced by owners post rebuild, I don't like the prospects of having a rebuilt engine put in a plane I am buying on one coast of the US, and immediately flying it back to my home base on the other coast.  

 

Educated opinions anyone?

[QuentininVA]

BTW: I looked up the AD the first service center quoted, and what I was told was correct. I just wonder if there is another AD that supersedes or overrides that first one, and which requires engine removal and IRAN.

 

I've read some of some nightmarish failures experience in the first 100 hours of a rebuild operation. Having that happen in the middle of nowhere is not something I want to experience.

[Guest]

I wonder if anyone has correlated engine failure rates with regard to who did the overhaul, A&P or shop? As with annual inspections there seems to be a fair amount of discretion.

Not being critical, just curious, my local engine shop is a one man show with 40 plus years, never heard of one of his failing at birth.

Clarence

[ryoder]

Mine had a pro strike in the 80s and the owner overhauled the prop, inspected the engine, did a top overhaul, repainted it, and put it to sleep for fifteen years with an annual every five. Then it was bought and flown for a while and upgraded and now I own it. I am glad for that prop strike.

[BKlott]

One aspect of this is how thorough the inspection is and is it even possible to determine all of the stress that was applied to the indiividual parts?

There have been reports over the years that seemed to indicate a higher incidence of airframe structural failures involving aircraft that have had prior damage history. Now, supposedly, all of those aircraft were also inspected, had repairs done and were signed off as airworthy when they were returned to service. Yet, many years and hours later, the hidden damage reared it's ugly head and the airframe failed.

I am not convinced that we have the capability (or if we do, that we take full advantage of those capabilities) to ascertain the true impact on metal parts caused by accidents. That is why damage history or prop strikes create some measure of doubt. Is it REALLY safe? If we are going to be totally honest with ourselves, we cannot be sure.

Some pilots address the issue by avoiding aircraft with damage history of any kind or missing log books. That approach doesn't give you any guarantees either but it does eliminate some potential problems.

Take it to the extreme and say, okay I've had a prop strike. Buy a new engine and propellor. You are then making the assumption that the parts in the new engine and the propellor assembly are all metalurgically sound and were properly assembled. Right?! So how do we determine that they are?

No easy answer to this stuff.

[chrisk]

My plane had a prop strike before I bought it, however the engine was overhauled at Triad long after the prop strike.  It wasn't a problem for me.  If a  plane is for sale with less than 250 hours on it since a prop strike, I would be very cautious and have to look into the details.  If it was a well known engine shop, I would probably be ok with it.  If I didn't know the shop, I'd probably pass.

[N601RX]

How does anyone know that their newly overhauled engine from Lycoming isn't a prop strike engine? It's even possible that the parts from a prop strike engine might be spread out among several engines.

[mooniac15u]

Not all prop strikes are equal.  Was the engine running?  Was it a sudden stoppage?

 

http://www.avweb.com/news/features/The-Prop-StrikeSudden-Stop222325-1.html

[Guest]

Here are the 2 service bulletins covering prop strike on Lycoming and Continental engines as viewed by them. The FAA has issued an AD on Lycoming but not Continental. Most insurance companies I've dealt with will pay for S/B compliance, its cheaper than troubles down the road.

http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20533B%20(10-04-2012)/Recommended%20Action%20for%20Sudden%20Engine%20Stoppage,%20Propeller-Rotor%20Strike%20or%20Loss....pdf

http://www.tcmlink.com/pdf2/SB96-11B.pdf

Clarence

[BKlott]

I'll share a real life example of hidden, un-discovered damage to an airplane that was involved in an accident. In fact, it was the 1964 C model Mooney that my Dad purchased in 1970.

The story goes that the Mooney was on a trip down to Mexico and was operating off of a strip down there. The airplane ran off the end of the runway, through a fence incurring wing damage and front fuselage damage along with a collapsed nose gear. The airplane was transported back to California and was rebuilt at Norman Larson Beechcraft at Van Nuys Airport. The rebuild took some one and one half years.

When my Dad and I spotted the Mooney for sale it had a brand new paint job, a zero time rebuilt Lycoming and an overhauled propellor. My Dad had the seats recovered and that Mooney looked better than new.

Shortly after he purchased it he asked me to steer the plane while we were taxiing. I pushed on the right rudder pedal and it went full forward but didn't feel quite right. in fact, it was stuck in the full forward position as it had broken.

The mechanic removed the entire rudder pedal assembly which I believe was a torque tube type assembly. He magna fluxed it and found several large stress cracks in the assembly. When he reported this to the FAA, they wanted to see the part. Subsequently there was either a Service Bulletin or Airworthiness Directive issued (or something, I was thirteen at the time so bear with me) that required this part be inspected on all Mooneys that had suffered a nose gear collapse.

The airplane had undergone a year and a half rebuild and that damage from the stress had not been discovered. Either somebody cut a corner or didn't forsee all of the potential problems that the accident could have created. Or they did and did check that part, the testing wasn't up to snuff or no defects were uncovered at that point in time.

The point is that when something like an accident or a prop strike occurs, the parts are subjected to stress and forces which they were not designed for. Consequently, the event introduces some unknown variables into the equation. How do any of us begin to quantify or mitigate the risks that these unknowns carry with them? I don't know the answer.

My thinking on the prop strike issue is that if the engine was running then you better have a very thorough tear down and inspection by someone that you trust implicitly AND that has all of the testing equipment needed to thoroughly check / magna flux/ eddy current, whatever, all the parts. If your engine is mid-time or closer to TBO, maybe you are better off buying new. Emphasis on "maybe".

[jetdriven]

A new lycoming engine is 50,000$. Fwiw