Pre buy concern

[billy hellcat]

I have read everything I can about this subject but always like other opinions.  I like this 1998 ovation I found for sale but am concerned about the engine and the plane not flying that much.  It has been in a heated hanger its whole life up in the Northeast area  and no expense spared MX performed. TT 1300 SMOH 700. Overhaul done 15 years ago.  It's original avionics which doesn't bother me as I can get the panel I want.   My concern is looking at the compressions over the years they have been slowly going down which is normal.  As of 2 months ago they are as follows: # 62 #62 #3 67. #4 60 #5 65 #6 60.   They were in the low 70'S  11 years ago at 350 hours SMOH.  I know continentals have lower compressions and it doesn't tell you much.  What items should be done at prebuy (Boroscope, oil analysis, go fly it for a hour and half then do compressions, etc.)?  Anything else to do to protect me in the  pre purchase?    

[GeeBee]

Nice thing about a Continental is you can pull a lifter and look at the cam without pulling a cylinder. If you are concerned about corrosion, start with a borescope of the cylinders then look at the cam from the lifter holes.

[billy hellcat]

Thanks!  Boroscope pictures will be a must then for sure!

 

[NickG]

9 minutes ago, billy hellcat said:

Thanks!  Boroscope pictures will be a must then for sure!

 

Boresope. Also, lapping the cylinders might really help. Flying it and running the engine and operating it properly will help the most. As long as compressions are above the master orifice youre OK, I believe. 

[Utah20Gflyer]

I wonder why it had a major engine overhaul at 600 hours?  That seems really early.  
 

Depending on how the compression check was done the low numbers could be a result of the engine not being properly warmed up right before the test.  Also compression is only one factor in determining the health of a cylinder.  Cylinders in the 60s with normal oil consumption wouldn’t bother me at all.  Not even a little bit.  
 

I’d want to do my own compression test with the engine warm and then bore scope the cylinders.   Oil consumption can be difficult to determine objectively unless the owner tracks adding oil between oil changes like I do.  I’d ask if he has records of that.  

[billy hellcat]

45 minutes ago, Utah20Gflyer said:

I wonder why it had a major engine overhaul at 600 hours?  That seems really early.  
 

Depending on how the compression check was done the low numbers could be a result of the engine not being properly warmed up right before the test.  Also compression is only one factor in determining the health of a cylinder.  Cylinders in the 60s with normal oil consumption wouldn’t bother me at all.  Not even a little bit.  
 

I’d want to do my own compression test with the engine warm and then bore scope the cylinders.   Oil consumption can be difficult to determine objectively unless the owner tracks adding oil between oil changes like I do.  I’d ask if he has records of that.  

it had a prop strike so the owner overhauled it to be safe.  that happened at around 600

[PeteMc]

4 hours ago, billy hellcat said:

it had a prop strike so the owner overhauled it to be safe.  that happened at around 600

Have a someone that knows take a REALLY CLOSE LOOK at the logs.  When I went to buy my plane it was being sold as X hrs SMOH, but even when I looked at the logs it raised some red flags.  It also had had a prop strike and when they did the teardown they did a LOT of work on anything that looked worn or concerning.  But it was just very close to an overhaul, but not quite.  So just make sure it was an real, official overhaul and not a teardown and rebuild due to the prop strike. 

[gabez]

I bought a j35 few years back, didn't fly much with previous owner (lost medical .. the usual deal), always hangared. compression were low flew it as much as I could, next annual compressions were much better.  

[Falcon Man]

If I was in the market for an airplane right now I would hire SAAVY to orchestrate the pre-buy inspection. They have a very good data driven approach.

I have bought and sold 7 Mooney airplanes over the last 40 years and something is always missed, even by MSC inspections. 

The advice over the years has been to avoid a hangar queen like this Ovation you are interested in. My current 1986 252 was a hangar queen with 1700 hrs TT and recent IRAN from a prop strike when I bought it 4 years ago and it has had the least amount of airframe or engine issues of any of my other aircraft.

There is a lot to be said for low time airframes if they have been hanged and maintained well.

[dkkim73]

I did not use savvy for pre buy because I'd already started the process and they won't jump in after the fact. 

But my experiences with their mx program make me think they'd be very valuable in the pre buy phase. 

Definitely second getting an expert to help you with the logs. 

Also Mooney specific mechanic when/if it gets to the point of looking at airframe specifics. 

[billy hellcat]

4 hours ago, Falcon Man said:

If I was in the market for an airplane right now I would hire SAAVY to orchestrate the pre-buy inspection. They have a very good data driven approach.

I have bought and sold 7 Mooney airplanes over the last 40 years and something is always missed, even by MSC inspections. 

The advice over the years has been to avoid a hangar queen like this Ovation you are interested in. My current 1986 252 was a hangar queen with 1700 hrs TT and recent IRAN from a prop strike when I bought it 4 years ago and it has had the least amount of airframe or engine issues of any of my other aircraft.

There is a lot to be said for low time airframes if they have been hanged and maintained well.

I actually have signed up with savvy to help with the prebuy!

[1980Mooney]

On 5/7/2025 at 6:07 PM, billy hellcat said:

I have read everything I can about this subject but always like other opinions.  I like this 1998 ovation I found for sale but am concerned about the engine and the plane not flying that much.  It has been in a heated hanger its whole life up in the Northeast area  and no expense spared MX performed. TT 1300 SMOH 700. Overhaul done 15 years ago.  It's original avionics which doesn't bother me as I can get the panel I want.   My concern is looking at the compressions over the years they have been slowly going down which is normal.  As of 2 months ago they are as follows: # 62 #62 #3 67. #4 60 #5 65 #6 60.   They were in the low 70'S  11 years ago at 350 hours SMOH.  I know continentals have lower compressions and it doesn't tell you much.  What items should be done at prebuy (Boroscope, oil analysis, go fly it for a hour and half then do compressions, etc.)?  Anything else to do to protect me in the  pre purchase?    

No-one has mentioned it so I am going to state what may seem obvious to current Mooney owners but many not be to someone new to Mooney's.  Although the owner may claim that the plane has been in a heated hangar its whole life in the NE, you still need to have a thorough inspection for corrosion by a Mooney expert.  Another MooneySpace member bought a Mooney in the NE in 2022 (from another MooneySpace member) and he shared his sad story with us.  The Buyer (located in Texas) had a pre-buy inspection done by a Mooney Service Center (MSC) in the North East.  Everything looked good so he purchased it.  It needed an Annual before going to Texas, so the Buyer had the MSC continue the Pre-Buy and turn it into an Annual.  During the Annual, the MSC (yes the same one that did the Pre-Buy) found heavy intergranular defoliation corrosion on the lower cap on RH wing stub spar assembly inside inspection panel area directly behind RH gear wheel well.  Metal had flaked away. 

I can't find all the posted detail now, but the Buyer said that the corrosion was not easily visible from the inspection ports.  A pro needs to know where to look and to use mirrors on an extension or a borescope.

The plane was now Not Airworthy.  It had to be ferried to Don Maxwell in Longview for major repair.  He posted that the repair cost was $27.5k and took 1 year. That doesn't include the cost of the useless Annual done by the shop that missed the corrosion to begin with, the cost of the Ferry, the Buyer's fixed costs, the Buyer could not stay current without renting a plane and by the time the wing was repaired it needed another Annual.  I bet he spent another $10k+ in the meantime.  The Buyer had to pay it - the Seller and the MSC had no liability since the sale had already closed. 

A PreBuy is not a guarantee.  It is just an opinion.

 

Edited May 9 by 1980Mooney

[jetdriven]

Thats why a prebuy and an annual are not the same.  You should spend more time looking for corrosion and damage and skip the servicing.  Since most people are not following the factory checklist, and not looking at it too in depth, this stuff gets missed.

[MikeOH]

I'm pretty much a cynic when it comes to the whole pre-buy/annual discussion.  Warning: the following is my OPINION only and based on my SINGLE purchase experience combined with countless tales/stories/nightmares read here on our hallowed forum

1) Many looking for a pre-buy are newbies like I was nearly 8 years ago.  As such, I didn't know what I didn't know. Pretty poor position to be in when dealing with A&Ps for such a significant purchase with possible financially dire consequences post purchase.

2) No specific meaning or requirements for a pre-buy. And, see #1, how do you know what to specify when you've never done this before??  My pre-buy at a MSC revealed only a few minor issues that, even as a first time owner, didn't strike me dealbreakers .  However, the MSC completely missed a leaking prop hub!  That was a pricey thing to miss and one I think they should have found as part of a pre-buy.  But, I'll admit that I didn't  specifically ask them to check the prop. Having never purchased before all I told the MSC was to look for 'show-stoppers'/corrosion.  Live and learn, I cynically say.

3) Annual is the WRONG thing to have done.  While it is a defined check-list my opinion is that it can (and has) failed to uncover MAJOR issues even if followed to the letter. (Sure, after purchase if you want 'fresh' annual, go ahead.  My point is I think it's a waste of money as a pre-buy)

4) What I did before spending a dime on a pre-buy was to look for consistent and frequent use over the last 3 to 5 years.  My logic is that that history 'proves' the plane was decently maintained, reliable and, in my case, safe enough that the owner flew his family around without concern.

5) If I had it to do over again as a first time buyer, I'd hire Savvy to handle the whole thing.  They are going to know where to take the plane and what to tell the shop to look for.

6) Now, as an 'experienced owner' if I was looking at another Mooney purchase I'd do the same recency of use screening, look the logs over myself (now that I know how to do that), borescope the cylinders and valves myself (I own a borescope), inspect for corrosion and skip spending the money on a pre-buy.

7) Bottom line: It's a bit of a crap shoot NO MATTER WHAT YOU DO!  Being able to come up with $50K, worst case, after purchase (especially if financed) is important to your sanity, IMHO.

All of the above may only be worth $0.02 on a good day

 

I would be curious if @KLRDMDwould share if he routinely paid for pre-buys on the multitude of aircraft he has purchased over the years.  Seems whatever his method, it's been pretty successful based on sheer volume

[A64Pilot]

8 hours ago, jetdriven said:

Thats why a prebuy and an annual are not the same.  You should spend more time looking for corrosion and damage and skip the servicing.  Since most people are not following the factory checklist, and not looking at it too in depth, this stuff gets missed.

I’ve said that so many times here for many to decry that I don’t know what I’m talking about etc that I’ve stopped. An Annual is not a maintenance activity or servicing, it’s an Inspection activity, it’s in the name.

Sure there can be excellent pre-buys, however there is no definition of a pre-buy, as far as the FAA is concerned there is no such thing. There is no list of things that must be inspected. A Pre-buy can be a pre-flight or a nearly complete tear down, if you insist on a Pre-buy for God’s sake have a written contract where every inspection you want performed is listed and signed off with results noted.

I won’t perform a Pre-buy myself without the purchaser participating, but I’m Retired and not having to make a living turning wrenches.

However the Annual is defined, it has a min performance requirement etc. Any IA that’s not a fool treats an Annual seriously as their Professional License is on the line, pre-buy they may have the new kid do because they are busy and the purchaser wants it done now, who knows? 

Any decent mechanic if conducting a pre buy can tell you on day one if you ought to give this airplane a pass or it’s most probably a good one. If they say it’s most likely a good one, then in my opinion you turn that pre-buy into an Annual, which of course takes an IA. If they tell you they keep running into sloppy maintenance and unairworthy items, then let it pass.

Ideally you want the person who you intend to care for the airplane to conduct the pre-buy / Annual. That way they have skin in the game.

There have been many posts in this forum that I have read that talk about the serious issues found on the first Annual, that were missed on the pre-buy. Most mechanics take an Annual more seriously, because it’s legally defined and has a list of items that must be inspected. They can get into trouble with an Annual, but not a pre-buy.

I’m not sure why but apparently an annual for many people has turned into a major maintenance activity where there is a lot of services performed, instead of the inspection activity it’s supposed to be, maybe it’s to increase revenue, or more likely it’s because the owner wants to get all that over with at one time, rather than performing such servicing themselves as preventative maintenance.

Most pilots I guess will not even change oil, some shouldn’t.

[DCarlton]

19 minutes ago, A64Pilot said:

I’ve said that so many times here for many to decry that I don’t know what I’m talking about etc that I’ve stopped. An Annual is not a maintenance activity or servicing, it’s an Inspection activity, it’s in the name.

Sure there can be excellent pre-buys, however there is no definition of a pre-buy, as far as the FAA is concerned there is no such thing. There is no list of things that must be inspected. A Pre-buy can be a pre-flight or a nearly complete tear down, if you insist on a Pre-buy for God’s sake have a written contract where every inspection you want performed is listed and signed off with results noted.

I won’t perform a Pre-buy myself without the purchaser participating, but I’m Retired and not having to make a living turning wrenches.

However the Annual is defined, it has a min performance requirement etc. Any IA that’s not a fool treats an Annual seriously as their Professional License is on the line, pre-buy they may have the new kid do because they are busy and the purchaser wants it done now, who knows? 

Any decent mechanic if conducting a pre buy can tell you on day one if you ought to give this airplane a pass or it’s most probably a good one. If they say it’s most likely a good one, then in my opinion you turn that pre-buy into an Annual, which of course takes an IA. If they tell you they keep running into sloppy maintenance and unairworthy items, then let it pass.

Ideally you want the person who you intend to care for the airplane to conduct the pre-buy / Annual. That way they have skin in the game.

There have been many posts in this forum that I have read that talk about the serious issues found on the first Annual, that were missed on the pre-buy. Most mechanics take an Annual more seriously, because it’s legally defined and has a list of items that must be inspected. They can get into trouble with an Annual, but not a pre-buy.

I’m not sure why but apparently an annual for many people has turned into a major maintenance activity where there is a lot of services performed, instead of the inspection activity it’s supposed to be, maybe it’s to increase revenue, or more likely it’s because the owner wants to get all that over with at one time, rather than performing such servicing themselves as preventative maintenance.

Most pilots I guess will not even change oil, some shouldn’t.

Why the heck then are mechanics required to remove the wheels every annual and repack the bearings.  That's always seemed like excessive "maintenance" to me.  

As an owner, anything that takes more than a week (two weeks to a month) feels like major maintenance even if it's only 24 billed hours of work.   Remove the cowling, belly pain, inspection panels, spinner, wheels, oil filter, plugs, injectors, along with putting it up on jacks, and heck you might as well dive in big time.  

[EricJ]

45 minutes ago, DCarlton said:

Why the heck then are mechanics required to remove the wheels every annual and repack the bearings.  That's always seemed like excessive "maintenance" to me.  

There is no requirement to remove wheels or repack bearings for an annual or 100-hour inspection.

FAR 43 Appendix D describes the scope and detail of 100-hour and annual inspections.  Item (e)(7) in the landing gear section says:

(e) Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the landing gear group:

... (7) Wheels—for cracks, defects, and condition of bearings.

Many inspection items are done blind, like inspecting the condition of rings and valve seats via a compression test, or the condition of seals or gaskets by leak checks, etc.  Likewise "condition of bearings" can be tested without removing the wheels, and wheel crack inspections may be done visually, with mirrors or borescopes for parts that are otherwise difficult to see, etc.   All of this is done to the satisfaction of the IA, and some may feel that it is necessary to remove the wheels to be comfortable with assessing the conditions of the components, and I think some do it just to assure that the bearings get adequately lubed as that is an oft-neglected component sometimes.    The bottom line is that there is no requirement in FAR 43 Appendix D to service anything, except that it is required to "thoroughly clean the aircraft and engine" in Section (a), the very first item in the list.  Everything else is just inspection.

There may be components, like propellers, that require or suggest annual maintenance in their ICA, and most folks let those coincide with the annual inspection, although it is not required to do so, and ICAs aren't mandatory for Part 91, anyway.   Some ADs might have annual requirements, or requirements that are just dealt with at annual for efficiency.

I think annual inspections tend to grow in scope because many use it as an opportunity to catch up on deferred maintenance, i.e., they just leave stuff unaddressed to be handled at annual.   An airplane with no deferred maintenance would be expected to have an easier time at annual, but even so, if the deferred items aren't airworthiness concerns or covered in Appendix D, they don't really even need to be addressed at annual inspection.   It is in a shop's interest to point out as many things as they think they can get hired to fix, so often that's what they do.   

[N201MKTurbo]

I was told by an FAA guy once that the only way to inspect the condition of the bearings was to clean them and visually inspect them. Of course this requires that they be repacked.

It does seem like a ridiculous waste of time doing it every year. But there is no required inspections with a greater time span than the annual. You could try to get an AIP for your airplane with a longer inspection interval.

[DCarlton]

2 hours ago, EricJ said:

There is no requirement to remove wheels or repack bearings for an annual or 100-hour inspection.

FAR 43 Appendix D describes the scope and detail of 100-hour and annual inspections.  Item (e)(7) in the landing gear section says:

(e) Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the landing gear group:

... (7) Wheels—for cracks, defects, and condition of bearings.

Many inspection items are done blind, like inspecting the condition of rings and valve seats via a compression test, or the condition of seals or gaskets by leak checks, etc.  Likewise "condition of bearings" can be tested without removing the wheels, and wheel crack inspections may be done visually, with mirrors or borescopes for parts that are otherwise difficult to see, etc.   All of this is done to the satisfaction of the IA, and some may feel that it is necessary to remove the wheels to be comfortable with assessing the conditions of the components, and I think some do it just to assure that the bearings get adequately lubed as that is an oft-neglected component sometimes.    The bottom line is that there is no requirement in FAR 43 Appendix D to service anything, except that it is required to "thoroughly clean the aircraft and engine" in Section (a), the very first item in the list.  Everything else is just inspection.

There may be components, like propellers, that require or suggest annual maintenance in their ICA, and most folks let those coincide with the annual inspection, although it is not required to do so, and ICAs aren't mandatory for Part 91, anyway.   Some ADs might have annual requirements, or requirements that are just dealt with at annual for efficiency.

I think annual inspections tend to grow in scope because many use it as an opportunity to catch up on deferred maintenance, i.e., they just leave stuff unaddressed to be handled at annual.   An airplane with no deferred maintenance would be expected to have an easier time at annual, but even so, if the deferred items aren't airworthiness concerns or covered in Appendix D, they don't really even need to be addressed at annual inspection.   It is in a shop's interest to point out as many things as they think they can get hired to fix, so often that's what they do.   

I need to revisit FAR 43 Appendix D which I assume is the basis for the 20-24 hours typically charged for a Mooney annual.  That seems to be industry standard.  

I'm not a licensed mechanic but repacking the wheel bearings every year always seemed too frequent to me.  Same with the fuel injectors and gascolator if you don't fly that many hours; hate to see those removed every year.  I would much prefer a progressive maintenance program if parts were readily available and you could schedule a task and get in and out of the shop in a few days.  However, if going into the shop means weeks or month(s), you might as well preorder parts and plan ahead for the annual.  A year flies by.

[EricJ]

12 minutes ago, DCarlton said:

I need to revisit FAR 43 Appendix D which I assume is the basis for the 20-24 hours typically charged for a Mooney annual.  That seems to be industry standard.

Appendix D is the minimum regulatory requirement.   There is also a regulation that an inspector must use a checklist, and Appendix D is the minimum checklist.   Other checklists can be used, like the factory checklist, but they must contain all of the items in Appendix D.

12 minutes ago, DCarlton said:

I'm not a licensed mechanic but repacking the wheel bearings every year always seemed too frequent to me.

I came to the same conclusion, especially after repeatedly repacking bearings that were still full of good grease.   There's a tradeoff between doing useful maintenance and increasing the risk of maintenance-induced failures, and doing stuff too often is not productive and adds risk.

12 minutes ago, DCarlton said:

Same with the fuel injectors and gascolator if you don't fly that many hours; hate to see those removed every year.

Agreed.   The Lycoming service document on cleaning injectors warns that excessive cleaning of the injectors is detrimental.

[midlifeflyer]

15 hours ago, MikeOH said:

I would be curious if @midlifeflyer would share if he routinely paid for pre-buys on the multitude of aircraft he has purchased over the years.  Seems whatever his method, it's been pretty successful based on sheer volume

Huh? 

[A64Pilot]

10 hours ago, DCarlton said:

Why the heck then are mechanics required to remove the wheels every annual and repack the bearings.  That's always seemed like excessive "maintenance" to me.  

You have had some good answers already. I’ll tell you what I do on most Annuals now, but of course this is what I do, I’m not saying it’s what should be done by others, but I believe each aircraft and the conditions and frequency it’s operated and stored in should be taken into consideration.

Realize my Annuals I do are for older Retired guys with Champs, Cubs and the like, not fire breathing twin turbo complex aircraft that fly in the flight levels and fly hundreds of hours a year, none fly 100. They also almost never spend a night outside or in the rain.

The problem as I see it is there is an attempt to cover every aircraft flown in every environment under every condition with one yearly inspection, then add in the most conservative response is to do it and we see why wheels are pulled on aircraft that fly less than 50 hours a year and have never been rained on. The FAA relies and gives mechanics the ability to use their experience to adjust the scope of an inspection, but not the frequency.

I jack up the wheel, check for radial and axial play, spin it, check for noise and smoothness, in my opinion I have inspected the bearings. Fuel injectors, comply with the AD of course, check for condition and security, leaks and if operation is normal I don’t remove them. I do clean, inspect and repack bearings if the wheels are removed like for example tire replacements. If aircraft wheels were sealed as well as automobiles are then we could not bother but they aren’t, if water ever gets to the axle for example, they need to be repacked.

I do check engine oil filters / screens and we usually change the oil, but if it was changed last month and 5 hours ago I recommend we don’t. Compression test, borescope, check / adjust timing. Rarely bead blast plugs, I’m of the dig the carbon / lead out and don’t blast myself. I do check resistance.  Condition and security of everything else. I do require checking of all flight and engine control ends as in every bell crank pulley etc, run a Cossosion-X soaked rag over every inch of control cables looking for meat hooks, pulleys for wear / play etc. Gascolators are just too easy not to do, and occasionally I find evidence of deteriorating fuel lines, looks like black granular bits. I think that’s often what clogs injectors (opinion)

Owner does all of the manual work, cleaning, and usually if we have to pull mags etc they do so under my supervision, now not all are at the level I’m comfortable with, for those I do the technical stuff myself.

For that I charge $300 and I approach Annuals as a teaching event for the owner. Not that I want or expect them to do more than they should unsupervised but I think it helps understand how things work if you took it apart and put it back together yourself.

Those that own and fly twin Comanche’s, Bonanza’s and the like there are local Professional shops that usually specialize in a Type that I recommend for them.

 

Edited Sunday at 12:42 PM by A64Pilot

[MikeOH]

4 hours ago, midlifeflyer said:

Huh? 

@midlifeflyer

My bad; I confused you with another poster that has owned a size-able number of aircraft. Wish I could remember his name!

[midlifeflyer]

18 minutes ago, MikeOH said:

@midlifeflyer

My bad; I confused you with another poster that has owned a size-able number of aircraft. Wish I could remember his name!

Best one of those I've seen was a local business journal that did a local aviation article that said I owned a jet. 

[Fly Boomer]

15 hours ago, A64Pilot said:

Most pilots I guess will not even change oil, some shouldn’t.

Too true.  That made me smile.