kommers Posted August 27, 2015 Report Posted August 27, 2015 Question to all Mooney experts: I am on a market for M20J and recently came across quite decent 1986 bird that landed gear up due to the pilot error which, of course, resulted in a prop strike. Plane has been repaired and put up for sale by the Mooney shop. I came very close to signing a deal on it when my local mechanic who used to service my M20C stopped me with one simple question: has the engine been overhauled after the prop stirke? The answer was "no" and then my mechnic told me that such engine poses a serious danger of prop stoppage especially at takeoff. I asked Mooney shop owner and he replied that repairs have been conducted in accordance with AD 2004-10-14c1 and since then the plane has been flown for quite a bit. Since I don't have enough knowledge to make determination who is right and who is wrong here, I ask you folks to express your opinion here. Considering, that, unlike a cat, I have just one life, what my mechanic said may be a show stopper for this deal unless I hear something positive here on this forum. Thanks in advance ! Quote
KSMooniac Posted August 27, 2015 Report Posted August 27, 2015 Lycoming publishes documentation on what must be done after a prop strike. It does NOT mandate a full overhaul. but many folks choose to do so because the incremental cost to go from a tear-down inspection to an overhaul is not very large in aviation terms. You need to see the documentation of the work that was done after the prop strike, and compare that to Lycoming's publication and then make a decision. Quote
M20F Posted August 27, 2015 Report Posted August 27, 2015 Speaking strictly for the engine/prop and the strike itself. If it happened 29yrs ago and it hasn't caused the engine to fly apart yet, I wouldn't worry too much about it. Did you tell your mechanic the date when you asked the question about the strike? My bigger concern would be the engine has gone at least 29yrs without the case being split which is a long time. Quote
kommers Posted August 27, 2015 Author Report Posted August 27, 2015 This is what Mooney shop owner said exactly in his message: "We complied with everything that the factory requires. AD 2004-10-14c1 has been done" " Quote
philiplane Posted August 27, 2015 Report Posted August 27, 2015 Lycoming does not require a tear down. You are subject to the crank gear AD as a result of the prop strike. That is simply removal of the accessory case, inspection of the gear, and replacement of a bolt and lock tab. It is recommended to inspect the magnetos if the engine was subject to sudden stoppage. In any event, insurance companies are always happy to foot the bill for the inspections and repairs but not for a full overhaul. It gets an insurer off the hook for future claims. So the question is, why didn't the engine get a tear down inspection? When they said the repairs were done due to the AD, that is the minimum level of repair and doesn't involve any internal engine inspection other than the single gear on the back of the crankshaft. If there was no tear down done, you have no way of knowing that the crank and rods are unaffected. More than one crankshaft has failed just behind the propeller flange as a result of an old prop strike where the engine was not torn down. A simple run-out check will tell you only if the flange is straight, not if it has been overstressed. You need a magnetic particle inspection of the crankshaft which can only be done during a tear down. Again, any insurance company is happy to pay for this. Of course, the owner may not have had hull insurance, and wouldn't pay the $8k or more cost out of pocket. In which case the shop simply does the gear AD and bolts on a new prop. Cheap. By the way, if the propeller had damage requiring blade replacement, the hub is considered scrap and you would have to replace the prop. Was that done? Quote
Guest Posted August 27, 2015 Report Posted August 27, 2015 In addition to the AD and the associated SB 475, here is what Lycoming says about prop strike inspections: 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 Here is SB 475C: http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20475C%20(01-30-2003)/Crankshaft%20Gear%20Modification%20and%20Assembly%20Procedures.pdf SB 475Cis the minimum required and is driven by the AD, SB 533B is technically optional but most insurance companies are willing to pay for complete tear down and inspection. It is possible that the owner did not have insurance and therefore did the minimum required by the AD. In many cases there is nothing wrong internally, engine are extremely tough, but at a minimum I would have the magneto overhauled and the carbon vacuum pump replaced. Clarence Quote
jetdriven Posted August 27, 2015 Report Posted August 27, 2015 I would deduct the right number to value the airplane as runout. Not because of the gear-up, sudden stoppage, and the cheap engine inspection. But because th engine was last verhauled 29 years ago and its time for another one. It only has core value. Quote
Guest Posted August 27, 2015 Report Posted August 27, 2015 How are we determining the age of the engine? Unless I'm missing something the airframe is a1986, with no mention of the engine time or date either way. All we know is compliance with the 2004 AD. Clarence Quote
M20F Posted August 27, 2015 Report Posted August 27, 2015 How are we determining the age of the engine? Unless I'm missing something the airframe is a1986, with no mention of the engine time or date either way. All we know is compliance with the 2004 AD. Clarence I read it as occurring in 1986, my bad. Quote
kommers Posted August 27, 2015 Author Report Posted August 27, 2015 Well, I can add that the engine is 700 SMOH this is what is known Quote
kommers Posted August 27, 2015 Author Report Posted August 27, 2015 That unfortunately I am not aware of. Quote
Cruiser Posted August 27, 2015 Report Posted August 27, 2015 from the OP it sounds like this engine has a little time since the recent prop strike. IF the tear down inspection was performed by a reputable, experienced engine shop, and returned to service as airworthy the odds are it will continue to perform as expected. There is always risk. Some people are unwilling to accept this type of "known damage" risk. That is a PERSONAL decision you must deal with. The FAA says the engine is airworthy. Do you think the engine is airworthy? Will you trust it every time you leave the ground? Any more or less than any other engine? Safety aspects aside........ This aircraft has a huge black stain on it that will never go away. Do you plan to own it forever? Because if you want to sell it, you will limit the population of buyers by those that will never own it because of the prior damage history. A bad thing? Maybe, it will limit your ability to sell and by doing so, more likely devalue the plane unless you keep it past engine replacement, then the stain goes completely away. (except for the gear up) Quote
jetdriven Posted August 27, 2015 Report Posted August 27, 2015 That unfortunately I am not aware of.i would ask that question before discussing particulars of a prop strike inspection Quote
kommers Posted August 27, 2015 Author Report Posted August 27, 2015 Yes, this is a very wise elaborating on a balance between what is okay by the standards and what gut feelings a person may have... having lost my M20C due to the gear collapse after the landing and getting through that experience emotionally and pschycologically thereafter, I don't think that either my wife or myself want to put ourselves into the state of doubt every time we pull the yoke... I need a plane which damage history will be limited to the cut in the seat upholstery, that's about it, I don't want to live by expectation, however little the chance is, that iit may fail any moment because cranks and rods were affected but it was not detected.. 2 Quote
jetdriven Posted August 27, 2015 Report Posted August 27, 2015 You should consider a brand new Cirrus. No chance of anything having even been been damaged, and if it quits a parachute. In all seriousness You are looking at a 29 year old plane. You can't be sure about anything. I'd find out how old the engine is and go from there. 1 Quote
KevinR Posted August 27, 2015 Report Posted August 27, 2015 'Legal' and 'safe' are two different concepts in aviation. Sort of like when my 19 year-old self took off in marginal VFR weather, at night, with two (non-pilot) friends, three hours after passing my private pilot check-ride and headed out to a short runway on an island. Legal? Yes. Do you really want to be wondering about that prop strike every time you take off? Two hundred feet off the ground is a lousy time for a catastrophic engine failure. A prop strike from a gear-up is about as severe as it gets. Engine running, prop instantly stops. Ouch. I've heard of significant internal engine damage from just hitting some thick grass. Try punching the runway with your bare knuckles, then imagine doing that with 60 horsepower pushing your arm (idle power). As for the damage history, it all comes down to the quality of the repairs and the reputation of the repair shop. Structural or cosmetic? Mooney's are tough birds. If the damage history is factored into the price, it's reasonable to assume you will be ok at resale. In my experience, the more time that passes since damage, the less impact the damage has on the price. Now is the perfect time to deal with the problem. If I were buying, I'd negotiate an overhaul into the price. Quote
Bravoman Posted August 27, 2015 Report Posted August 27, 2015 I for one agree with cruiser. I would not buy an aircraft with a damage history such as a gear up. My feeling in this regard may not be logical to everyone, but I have spoken with lots of aircraft owners who feel and act the same. That is why I have never bought the argument that the value diminution evaporates over time. There is a distinct segment of the market which are not takers at any price and that has to negatively effect value. 1 Quote
PTK Posted August 27, 2015 Report Posted August 27, 2015 The way I see it Kommers is that this is a case of a 29 yo engine that suffered sudden stoppage from a prop strike. The seller did the cheapest bare minimum in order to get it "legal" and sell it. What other repairs were done on the cheap? How will you feel every time you apply power and pull the yoke? Would you trust it with your family and pax? How will they feel when you tell them? What do you think you should do? Hint: start by listening to your mechanic! Quote
Shadrach Posted August 27, 2015 Report Posted August 27, 2015 Yes, this is a very wise elaborating on a balance between what is okay by the standards and what gut feelings a person may have... having lost my M20C due to the gear collapse after the landing and getting through that experience emotionally and pschycologically thereafter, I don't think that either my wife or myself want to put ourselves into the state of doubt every time we pull the yoke... I need a plane which damage history will be limited to the cut in the seat upholstery, that's about it, I don't want to live by expectation, however little the chance is, that iit may fail any moment because cranks and rods were affected but it was not detected.. You need a brand new or nearly brand new plane... In the pool of airplanes that are 25 years of age or older, a significant number have some type of damage history, many even have the repairs logged (tongue in cheek). You can never "know" that plane has no damage history. The best we can do is to verify that the condition of the plane does not deviate from the picture painted in the logs. I don't understand the issue with keeping your current bird. If you buy it back and repair, you will "know" this bird far better than any other on the market. What's more, I'd bet the chances of landing the plane again without ensuring the gear is locked are minimal. Quote
Guest Posted August 27, 2015 Report Posted August 27, 2015 This all boils down to your risk tolerance. If you buy this plane and have a new engine installed, it has huge risk of infant mortality. The installing mechanic may screw up and cause problems, the airframe may have unresolved problems form the accident or some hidden error from construction at Mooney all those years ago. If you buy a new aircraft it contains just as many unknowns. Also, if you don't get type specific training in this very model you are at equal risk of being the cause of the next accident. There is no one size fits all answer. Clarence Quote
DAVIDWH Posted August 27, 2015 Report Posted August 27, 2015 Wise Chinese philosopher: " Some of best deals are deals that are never made". Many many grains of sand on beach, no need to fixate on one. My plane was purchased with run-out engine, but was priced accordingly. So as stated above, it just depends. Quote
kommers Posted August 27, 2015 Author Report Posted August 27, 2015 The issue is very easy to explain - or very hard whichever you prefer: no one was able to tell us why the gear collapsed. FAA conducted its own investigation and cited mechanical failure as possible cause. There were at least three factors in that incdident, both human amd nechanical, that might have played the critical roile but nobody will ever know for sure which one was the real culprit. I don't want to land the plane having back thoughts every time that the next moment my plane may turn into the pile of metal on the runway. For my wife, who was actually in left seat on that day, getting back into this airplane even on the ground, brings very painful memories. So, my bird has to fly... away Quote
Parker_Woodruff Posted August 27, 2015 Report Posted August 27, 2015 We live in a fallible world where mechanical things fail. However, the nice guys at Mooney engineered us a pretty good M20B-TN that will typically keep the three wheels rolling in a straight line if the gear is maintained per the Mooney maintenance manual. Based on the write-up in the previous thread, it doesn't sound like the gear was being adjusted in a precise manner IAW the manual. This can reduce the risk of such traumatic events taking place. Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.