M20J pre-purchase comparisons

[tcope]

I’m looking at buying a M20J and I’ve narrowed it down to a 1984 model with 5000 TT, 150 SMOH, original paint for about $86K or a 1989 model with over 10,000 TT, 650 SNEW, new paint but was used as a trainer for $65K. Both have what looks like stock avionics. I’m leaning toward the 1989 model since it is significantly less expensive and 5 years newer. I’m not concerned about it having twice as many hours as much as I am about it probably making several times more landings during training. What are your thoughts?

Edited August 24, 2020 by tcope

[carusoam]

Welcome aboard tcope...

I like the new Ovations...

That’s my thoughts...

What are your thoughts..?

There are different reasons for selecting a plane....

age and hours of the airframe don’t mean very much... if it has been taken care of like a forever-plane...

If it has been uncared for... unliked... ran out of money... age and hours aren’t a good thing...

Best regards,

-a-

[shawnd]

Schools typically leave their planes outside - so question for the trainer a/c would be what kind of weather did have to sit in, if it was sitting outside.

[tcope]

Good point. It was used as a trainer in St Louis, MO. So, probably hot and humid in the summer and cold and humid in the winter.  The older one is in Minnesota, so similar conditions but it says it was hangared. 

 With the 1984 model as a baseline, I see the value of the 1989 model as:

Engine 850 SMOH (I listed it wrong above) vs  150 SMOH: -$10,500

Newer paint: +$8,000

Not hangared: ? (Just guessing -$5k-10k. Corrosion, rubber seals, ?)

Used as a trainer: ? (Guessing -$5K-10K for landing gear parts if needed)

So, I’m guessing the newer one is worth about $12K-22K less and is selling for $21K less.  I have very little fixed wing experience so I’m looking for some help on my estimations and any insights on what you would expect from a airplane used as a trainer  

 

[shawnd]

Not hangared doesn't just mean dropping the purchase price by 5-10K. I am sure others will chime in here, but you need a really thorough pre-buy inspection. Corrosion can result in repair bills far higher than 10K. Sometimes, there no option but to junk the airplane.

For hard landings, there's gear rigging, parts etc. But there's also the issue of stress those landings cause on the rest of the frame. Were the tanks sealed recently? If so, who did it? Are they reputable?

Did the plane encounter prop strike b/c a student though they could force the plane down? If so, who did the repair work and what they did they replace? People / insurance companies can take the cheaper way out in these cases. 

Have you done a logbook inspection? Was the plane serviced by a reputable shop or a Mooney Service Center? Which one and how often? To save money, they have taken the cheaper road.

These may sound discouraging but now is the time to be vigilant. Better to have walked away from the plane now than having a $70-$80K stone sitting in your hangar. Getting a "really" good deal has more or less always proven to be a bad deal in the long run.

 

[PT20J]

Here's a neat spreadsheet that shows M20J changes by year. Somewhere in the mid-80's, the factory switched from zinc chromate to epoxy primer on the tubular structure.

The way I think about it that I'm really buying three components: Airframe, engine, avionics

For what it's worth, Mike Bush recommends getting the newest lowest time airframe you can afford (that's the part you can't change). There are so many factors regarding the engine that it may be best to purchase an airplane with a high time engine (appropriately discounted) and reserve enough money to replace the engine with one where you control the overhaul. Avionics upgrades are expensive. The previous owner will not be able to get anywhere near full value in a sale for what they put into recent upgrades. So, the best deal there is to buy one with avionics you can live with for a while -- you're getting any recent upgrades at a deep discount. Keep in mind that the first year or two usually have maintenance surprises no matter how thorough your pre-purchase inspection was.

Skip

201hist.xls

 

 

[tcope]

Thanks for the input.  All good things to consider before deciding if I want to spend the money for a pre-buy.  Neither ad mentions the tanks being resealed, and the avionics are about the same.  Both claim no gear up landings.  I checked on the epoxy primer date and found one source that said Mooney started using it post 1986 and another source said post 1987.  Either way, the 1989 plane I am looking at would have the epoxy primer and the 1984 plane would have zinc chromate (unless it has been repainted IAW Service Bulletin M20-208 in 1979).  Therefore the 1989 plane should have better corrosion protection, but it has been sitting outside for most of 31 years.  

So, it looks like greater likelihood of problems with the newer airplane but it does have some updates the older one doesn't, like inner gear doors, round corner windows, 28V electrical system, electrically operated cowl flaps, redesigned interior and stormscope. (Thanks for the spreadsheet, PT20J.)  I will request the logbooks for both airplanes and see if I can determine how they were cared for.  

[carusoam]

There may actually be a poll around here for how many hours are on your airframe...

Some Mooneys have done daily flights as traffic watch accumulating 10k hours...

So... airframe hours don’t give a hint to how the plane wears...

 

Your price for corrosion is an indication that you didn’t understand how evil the corrosion can be in airplanes... (not Mooney specific)

When doing a PPI there are certain types of corrosion to be looked for first...

There isn’t a need to finish the PPI after some types of corrosion are found...

PP thoughts only, not a mechanic...

Best regards,

-a-

[tcope]

Would an A&P normally find any corrosion during an annual inspection?  Is that something that would show up in the logbook or something I could find out from talking to the mechanic who has been working on the airplane?  Or do you have any other ideas on how I can reasonably find out if it has significant corrosion before I pay for a pre buy inspection?  

[PT20J]

There was a traffic reporter in the SF Bay area that flew an early M20J in the late 80's/early 90's. It was involved in a midair with a C-150 that was on a training flight with a student and instructor. The C-150 nosewheel bent the Mooney vertical stabilizer/rudder in half. Both planes landed and everyone survived to have a great story to tell. That Mooney was maintained by Top Gun. When it racked up 10,000 hours, Tom Rauch called the factory and asked them if there was anything special to look for and they said, "Dunno, never seen one with that many hours. Let us know what you find." Plane was fine and is still flying and owned my a MSer. Wonder how many hours it has on it now?

Skip

[carusoam]

I think MSer numero uno May have owned the above referenced Mooney... Ask Craig... 

He adorned it with the nicest all electric multi-color screen panel... one of the first to go all electric.

Before having to move up the aviation ladder...

Best regards,

-a-

[PT20J]

Just now, tcope said:

Would an A&P normally find any corrosion during an annual inspection?  Is that something that would show up in the logbook or something I could find out from talking to the mechanic who has been working on the airplane?  Or do you have any other ideas on how I can reasonably find out if it has significant corrosion before I pay for a pre buy inspection?  

A good A&P will look for obvious corrosion at annual and it should be an area of investigation during the pre-purchase inspection. The scary corrosion is anything involving the spar. The wheel wells expose the spar and should be carefully checked. Spilled soda in the back seat can be problematic as the plane sits about 5 deg nose high so any liquid runs downhill and soaks the lower spar cap with phosphoric acid (doesn't that make you want a Coke right now?). 

The tubular structure can get water soaked and the tubes externally corroded if the windows leak and the insulation hasn't been replaced with the foam. Inspection for that requires pulling the interior which isn't normally done during a pre-purchase unless there is reason to suspect a problem. According to Don Maxwell, the biggest problem is leaking pilot's storm windows (replace the seal). Water gets in and sits on a channel that is used to attach the interior plastic panels. The channel is PK screwed to the tubes. On the later epoxy primered planes these screws were sealed but on earlier ones they can rust out allowing water to enter the tubes and migrate to the bottom longitudinal where it sits and rusts out from the inside. The only way to check for this is to pull the rear seats, open the inspection holes between the spars and pull the tension bolts and run a magnet inside the tubes.

Personally, I would not buy a plane with zinc chromated tubes unless it had a recent reputable 208 inspection and foam insulation. Been there, done that, spent a lot of money to have a tube replaced.

Skip

[carusoam]

TCope...

The insidious nature of corrosion... it can occur fast enough to happen between annual inspections...

So...

To defend your wallet from corrosion issues... get your PPI to include this in their search...
 

While reading the logs, you won’t find active corrosion... you may find something they fixed...

Surface corrosion...

Inter granular corrosion...

One is worse than the other...

One is more common...

PP thoughts, not a materials engineer...

Best regards,

-a-

[tcope]

5 minutes ago, PT20J said:

A good A&P will look for obvious corrosion at annual and it should be an area of investigation during the pre-purchase inspection. The scary corrosion is anything involving the spar. The wheel wells expose the spar and should be carefully checked. Spilled soda in the back seat can be problematic as the plane sits about 5 deg nose high so any liquid runs downhill and soaks the lower spar cap with phosphoric acid (doesn't that make you want a Coke right now?). 

The tubular structure can get water soaked and the tubes externally corroded if the windows leak and the insulation hasn't been replaced with the foam. Inspection for that requires pulling the interior which isn't normally done during a pre-purchase unless there is reason to suspect a problem. According to Don Maxwell, the biggest problem is leaking pilot's storm windows (replace the seal). Water gets in and sits on a channel that is used to attach the interior plastic panels. The channel is PK screwed to the tubes. On the later epoxy primered planes these screws were sealed but on earlier ones they can rust out allowing water to enter the tubes and migrate to the bottom longitudinal where it sits and rusts out from the inside. The only way to check for this is to pull the rear seats, open the inspection holes between the spars and pull the tension bolts and run a magnet inside the tubes.

Personally, I would not buy a plane with zinc chromated tubes unless it had a recent reputable 208 inspection and foam insulation. Been there, done that, spent a lot of money to have a tube replaced.

Skip

What is a 208 inspection?  It sounds like the 1989 model plane may be better equipped to prevent corrosion since it has the epoxy primer, but it also has been exposed to the elements more.  

[carusoam]

208 is an inspection of the tubes...

A few planes sat outside without cover...

A simple window leak could allow water inside...

Some crappy insulation can hold moisture next to the tubes...

Newer planes have done really well at coming up with solutions to these challenges...

Owners with excess dough have come up with good solutions as well.... they call them hangars... 

Best regards,

-a-

[tcope]

The ad for the older plane says it has always been hangared, but I just looked at the pictures again and all the pictures show it tied down outside. Makes me wonder. 

[carusoam]

1 minute ago, tcope said:

The ad for the older plane says it has always been hangared, but I just looked at the pictures again and all the pictures show it tied down outside. Makes me wonder. 

 

Proof that you are smarter than they think you are.... 

Outside may be for pictures...

Tied down outside... may have been a really windy picture day...?

 

Buying a plane is going to feel like a full time job...

That you work at while working your other full time job...

Best regards,

-a-

[PT20J]

Here’s a link to Service Bulletin M20-208B.

https://cdn2.hubspot.net/hubfs/4147179/technical_documents/service_bulletins/sbm20-208b-1.pdf

There might be a clue to which serial numbers have epoxy primer by noting the effectivity for part B. The effectivity is strange because, I believe all M20Js have flush windows. 

I wouldn’t hesitate to call Jimmy Garrison at GMAX for his take. He’s a long time Mooney broker, very familiar with the market and a straight shooter. https://www.gmaxamericanaircraft.com

Skip

[tcope]

Yes, it is taking a lot of time to research different models, avionics, engines and maintenance problems. I find it interesting, though, and think I’ll probably be researching issues more after I get an airplane. Mooney space seems like a great community. 

[carusoam]

Airplane ownership will be one of the highlights of your life...

Somewhere after being married and having kids...

Probably before having your own business...

Best regards,

-a-

[tmo]

The business analogy I like.

[jlunseth]

11 hours ago, tcope said:

The ad for the older plane says it has always been hangared, but I just looked at the pictures again and all the pictures show it tied down outside. Makes me wonder. 

Is that the J at Thunderbird? If it is, I can tell you for sure it has always been hangared - right next to mine. 

[tcope]

It says it’s at Flying Cloud Airport in Minnesota. 

[carusoam]

Winner! https://www.airnav.com/airport/KFCM
 

-a-

[tcope]

Ah, ha! So, there is Thunderbird Aviation there.  That’s good to know that that airplane was actually hangared.