Prebuy Effective Use of Time

[bigmo]

I have a contract on my plane I'm selling, so it's time to get serious.

I was only looking at J's originally, but have found 3 pre-J's that are serious contenders. All meet all my requirements (clean logs, no damage history, mid time motor, autopilot w/ altitude hold). This comes for a price, right at $100K...but it's hard to beat the bang for the buck. There's still one turn-key J I have my eye on, but it's literally double the $ and aside from having a J with killer aesthetics, it doesn't get me much.

I have a longstanding relationship with my A&P. Experienced, detail oriented, retired military mechanic. I've done all the initial logs review - no red flags. 

All have good pedigrees, no log shenanigans, and all are in great shape. One is sitting with Jimmy @ Gmax.

Assuming we have 6-8 hours to do a solid once-over - where do you spend your time?

Two of the three have recent bladders (< 10 years).

All three have seen a decent amount of maintenance at well known MSCs.

This is my third a/c purchase, so I'm not going in blind. But, I'd like to know from experience where the big dollar items are that we should focus our efforts on.

2 are IO-360, 1 is O-360 - carbs don't scare me and it has at JPI EDM900

 

All three are "fly away ready" - that being said, I have some minor avionics plans to add GPSS/roll steering and ADSB-in.

 

Keen to hear a 1-n list of areas you'd start with based upon time. We'll spend 2+ hours on the motor and verify compression and borescope cylinders. All will be flown and all systems checked. After that, where's my (well, my A&P's) time best spent?

MANY thanks...we're almost there!

 

[KSMooniac]

Corrosion is the number one deal-breaker to check. Steel tubes in the cabin behind the plastic. Spar under the back seat and wheel wells, and inside the wing inspection panels.

Maintenance and operating history is next... Sitting long periods of time can lead to cam failure, but there is no easy way to inspect that in a Lycoming.

Sent from my motorola edge plus 2023 using Tapatalk

[PT20J]

There are a couple of good articles here 

https://knr-inc.com/shoptalk-articles.html

[redbaron1982]

Based on my own personal experience, corrosion, corrosion, corrosion. 

A corrosion free airplane with an engine that doesn't have hidden problems (oil analysis, borescope, compression test), can't give you in my opinion a lot of bad surprises. 

I'm a new owner, so don't have a ton of experience, but the experience I have has been quite painful. 

[bigmo]

23 minutes ago, PT20J said:

There are a couple of good articles here 

https://knr-inc.com/shoptalk-articles.html

This is gold - thanks so much!

[Fritz1]

Second corrosion, stub spar, wheel wells, fuselage tubes under window, cylinder barrels, then comes oil analysis, cylinder leak test and coloration of exhaust valves, before you go disect the logs, they will tell you if the birds are worth looking at

[cliffy]

Engines can be fixed- corrosion kills Mooneys!

The usual places-  Steel tubing inside the side walls under the windows, under the rear seat on the spar (access holes ),

in the wheel wells along the spar These are usually the big culprits.

One that most miss (and I have found one unairworthy because of) are the rivets in the spar between the main wheels.

Ask your A&P to check here for "smoking" rivets. It means they are loose in their holes.  If the airplane has had a good detail

cleaning you may not see these rivets smoking if they do. 

Make sure everything operates and works as it should Moe every knob and switch and see every light. 

Once money changes hands its all on you. 

[dkkim73]

4 minutes ago, cliffy said:

ound one unairworthy because of) are the rivets in the spar between the main wheels.Ask your A&P to check here for "smoking" rivets. It means they are loose in their holes.  If the airplane has had a good detail  cleaning you may not see these rivets smoking if they do. 

@cliffy thank you for the point-out on smoking rivets. 

[Andy95W]

 

[Zippy_Bird]

When I bought my M20E from GMAX two years ago, like you I did the log reviews myself with help from experienced professionals. I then hired a local AP to go onsite and do the pre buy. We prioritized the airframe first, engine second. He removed exterior airframe panels and some choice interior panels to inspect for aluminum corrosion and steal tubular corrosion. Airframe came up solid. Engine inspection and test runs also came up solid. With those inspections plus the logs I closed the deal. Hired a local Mooney instructor who ferried the plane to my airport and also did the insurance required transition training with me at home. Now, I am happy with my plane and the price, but this approach missed some things. Had we arranged to fly the plane and test all the instruments and systems, we would have caught some surprises before closing. We didn’t miss any deal killers, but I would have liked to negotiate a few squawks. Assuming the priorities of airframe and engine come good, recommend flying and testing everything.

One specific thing I’d look for (and test) is the fuel indication system. If it’s been upgraded awesome, but if original definitely test. Problems can be in gauges or senders and can result in an non-airworthy condition. Flight instruments can often be replaced one for one without much fuss, but repairing the fuel indication systems sucks for many reasons.

Good luck and keep us posted on the purchase!

[jetdriven]

A Problem with hiring a local mechanic is he’s likely inside the sphere of influence of the seller and if he blows up the deal, he  pisses off the seller and it’s his local reputation so I don’t think you can get a totally unbiased honest evaluation that way. 
 

[bixmooney]

For what it is worth, I wanted a Prebuy and kind of quick but could not find someone not related to the airplane. 
I found this someone who would do a mobile Prebuy and got more than I expected and very good information for me and hundreds of pictures and videos of the process, Mike Teager. 
idk if I can post his contact information but feel free to message me if anyone is interested.