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Buying a Mooney, very low time pilot. What to look for?


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If you haven't done a Mooney prebuy before I'll attach something I wrote here a long time ago. It should get you on your way 

 

Check that all the model numbers and serial numbers match on everything with the log book, engine, prop, airframe, I do radios also. Actually read the data plates and compare to the logs. Check that the parts actually installed match what is contained in the TCDS and/or the logs show an STC change for the big stuff and changes for radios and electronics. Anything added like engine monitors, fuel flow gauges, etc should show an STC listing in the log books. 

Pull the rear seat bottom and open up the inspection holes to check for corrosion on the spar caps. Look at the spars real well in the main wheel wells for same. 

As noted fill up fuel tanks the night before and look for leaks the next day.

If you can jack the airplane do a gear over center torque check. Make sure the A&P has the correct tools to do it.

While on jacks, move the main gears in and out toward the wing tips for excessive movement. Lift the main wheels to check for play in the donuts. The donuts should expand enough after 5 mins unloaded to not have much movement. Check the mouse boots for condition in the main wheel wells. While down by the main gear look at the spar bottom between the fuselage and wheel wells. Look for smoking rivets there. The rivets that hold the spar sandwich together. That can be a big $$$$$$. I found one in AU with almost every rivet loose on the bottom of the spar. It was grounded by the owner when Kerrville said it had to be repaired. 

Nose gear area - if on jacks this is easy- twist the nose wheel left and right to check for excessive play in the steering linkage. More than about 10-15 degrees either side of center before tightening up on the linkage is too much. You will see the slop way at the top of the nose gear on the rod end linkage up there.  

Most important on the nose gear! Look and feel for dents where the steering system touches on the tubing for dents where it touches. Turn the wheel by hand and you will see where it touches and stops. MAKE SURE THERE ARE NO DENTS THERE!

The limit is 1/32" depression. Any dents and the nose gear comes out for repair $$$$

On the tail surfaces grab the tip of the stabilizer and try to move it up and down and fore and aft. If it moves or clicks you might have work to do. Limits are about 1/10th of an inch either way. Usually fixed by changing out the "close tolerance bolts' in the hinge. As noted lift up on the rudder to check for play in the jackscrew. Same limit about 1/10 of an inch. Lots of times it is wear on the 2 bolt hinge bracket at the aft end of the jackscrew and not the jackscrew it self. I found one stabilizer that moved 1/2 inch either side of center!

Look over the outside surface of the entire airplane for dents, filliform corrosion, hangar rash (the elevator tips seem to be especially susceptible to this damage and NO repairs are allowed to control surfaces (no patches, partial skin replacement, etc). The FAA in one case here on MS made a big thing out of this stuff on a routine ramp check on one of our posters. Basically they said it didn't come that way from the factory so fix it. 

I check all the exterior control surface rod ends to see if they are loose enough to move or if dry and frozen. If dry and frozen I start looking at the logs real close to see if the lube and gear swing AD had been being done. 

One item missed almost always due to the effort but it can cause big headaches, is pulling the sidewalls inside and actually looking at the steel tubing frame for rust. If the windows are not sealed well, water gets in there and runs down inside on the tubes and rusts them. The insulation SB aside. There is actually a SB describing how to check for leaks by pulling the sidewalls and directing a water hose at the windows looking for leaks. 

Make sure everything, and I mean every switch, knob and button works as designed! Put power to it and try all radios in all modes, all lights, all warnings (landing gear warning horn, stall warning horn, etc), all exterior lights, everything that can be turned on or off or moved in and out. There was one write up on here a while back where someone bought a Mooney and the stall warning didn't work nor did the gear warning (IIRC). That makes the airplane unairworthy. 

If on jacks (and it should be) do a gear swing and make sure the gear works properly. I've seen them signed off 3 months ago and they hang 3" from the wells when sucked up. If its electric gear do a manual drop also to make sure it works. Had a couple on this board recently that went in for annual and the manual gear drop didn't work. So check it out. Look to see if the gear actuator has ever been removed, cleaned, checked for proper gear lash and relubed. If it hasn't you may be doing that on the next annual yourself  It's that important. Disregard if its a manual gear.

It goes without saying that a full log book check is required for all applicable ADs and required inspections even though the annual has just been done. The logs tell a story and knowing how to read them is a skill. Make sure you know what to look for or have someone that does. 

The engine stuff is the normal stuff. Compression check, oil filter inspection, looking for leaks, cracks, anything not normal. Pull the plugs and read them, they too have a story to tell. 

My caution to any whom I help buy an airplane? Trust no one selling an airplane period. Take nothing for granted. Don't trust anything even though it just had an annual. If you do, it will bite you in the arse. Check and verify everything before money changes hands. Once you pay for it , its yours!

Good luck and show us pictures even of the prebuy!   :-) :-)

 

 

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I don’t expect he will be soloing a 210, I concur insurence would be probably unlikely for a Student pilot, but the owner of Thrush had his kid taught in the company 210, he got his PPL in it, but was honestly dangerous he was so inexperienced. He only flew it once or twice, I figure he either scared himself bad or was smart enough to know he was in way over his head. But he got his ticket and could say he was a pilot I guess.

I assume it was possible from a Commercial insurence or maybe it wasn’t insured who knows?

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18 hours ago, AnAngryGoose said:

I'll be sure to find another A&P who has more experience with Mooney's than me. Thanks for the advice. 

Borescope is definitely planned. Hopefully that goes well. 

 

Any other specifics to look for?

Borescoping the engine won’t find airframe corrosion.  A corroded cylinder won’t scrap the plane, corroded wing spars and corroded fuselage tubing certainly can.

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Thanks everyone for the advice. I really appreciate it.

I did initial inspection today, more to come but so far everything seems good for the most part.

 

Logs all are up to date from what I've seen so far with STCs and P/Ns matching as they should. Wing spar in cabin and wheel well is in good condition, no notable corrosion found. Interior and exterior, including in inspection holes all looks great. I checked all flight controls for smooth, correct movement as well as excessive play in the rudder, horizontal stab, and flaps and they all look tight. I did a compression check on the cylinders and they all read nicely even after not running for quite awhile, better than expected. No notable leaks, cracks, etc in engine as far as I can see.

The only issue I have found is some light rust on super structure cage in the cabin, so far it doesn't seem bad. I think I should be able to polish it out with steel wool and coat with zinc chromate primer as none of it seemed very deep.

I still need to put it on jacks to check the compression disks but with it on the ground they seem to be in good condition. I plan on jacking it within the next few days. I also plan on doing a borescope inspection of the cylinders before I jack it.

Edited by AnAngryGoose
added info
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Some may disagree but I’ve had very good luck cleaning off most of the rust on a tube and then applying a rust convertor. It needs a slight bit of rust to remain. It chemically reacts with iron oxide and changes it I believe to iron phosphate, but it does stop further corrosion. Then paint over it if the black is ugly.

I think some surface rust on an aircraft this age is normal, just try to find deeper rust. The general rule is 10% of the thickness of a tube can be damaged, and as many tubes are awfully thin, there can’t be much damage without condemning the tube.

My J model had rust on a tube under the instrument panel, it confused me as it was isolated, then I realized the vent there was blowing on it, aircraft had done a lot of flying in the rain because some paint was missing from the leading edges, and I theorize that caused the tube to rust.

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On 9/25/2022 at 4:22 AM, bcg said:

I bought my C to finish my PPL in, nobody would even quote insurance for me while still a student.  They all said they will not cover a student pilot in a retract, end of discussion, thanks for calling.  I could afford to pay cash and self-insure, so that's what I did and am doing.  I've got 30 hours in it so far (16 of them being a trip from Tx to Ga and back last week) and I don't regret the decision at all, I absolutely love this bird.  There is a lot to manage in the pattern when you're practicing landings and pounding them out one after another, especially since this plane is so much faster than a trainer, so I'm extending downwind to slow things down and not feel rushed.  Other than that, I haven't really felt that it was that much more work than the Cherokee I was flying before and again, in the pattern the thing that's really increasing the workload is the speed of the plane, find a way to slow things down and it gets easier.  I say do it if you can, I think you'll be glad you did in the long run.

thank you so much for offering this.  I've been training in a cherokee 180, but have decided that it makes more sense to buy an M20c and just finish my training in that.  Flew a Cessna 172 yesterday and pretty much hated it.  would be fine to never get behind the yoke of one of those again.  i've got ~60 landings in a Cherokee in <14 hours of training.  Haven't had trouble yet (couple kinda ugly because...you know, student pilot), even had a tire blow out on one side on landing (on my first solo, no less). Not my fault, btw.  Perfect landing.  The aircraft owner is fairly aloof about some maintenance.  the tires were bald, the CFI was like "pish tosh", and then BOOM on the runway.  

Needless to say i fired that training outfit, and have decided to just buy a plane and hire an instructor (then i can be in charge of the tires).  

Really appreciate this post.  TY

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5 hours ago, A64Pilot said:

Some may disagree but I’ve had very good luck cleaning off most of the rust on a tube and then applying a rust convertor. It needs a slight bit of rust to remain. It chemically reacts with iron oxide and changes it I believe to iron phosphate, but it does stop further corrosion. Then paint over it if the black is ugly.

I think some surface rust on an aircraft this age is normal, just try to find deeper rust. The general rule is 10% of the thickness of a tube can be damaged, and as many tubes are awfully thin, there can’t be much damage without condemning the tube.

My J model had rust on a tube under the instrument panel, it confused me as it was isolated, then I realized the vent there was blowing on it, aircraft had done a lot of flying in the rain because some paint was missing from the leading edges, and I theorize that caused the tube to rust.

Ill ask around on this and try it in a small area and see how it works. I plan on replacing all window/door seals anyway to prevent this in the future. 

 

Thanks everyone for the advice. Both in flying and working on the Mooney. I'm excited for both. 

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Rusty tube is mostly a problem of the past…

When planes lived outdoors, uncovered…

When planes had an expected limit to their lifetime….

When fibrous insulation was left in place in contact with the tubes…

Light rust isn’t much of a problem…

 

water getting into the tubes and not draining out was a problem…

Tubes can corrode from the inside out when the plane is not cared for…

A simple cover works wonders…

:)

Read the logs, find the entry where the insulation was removed… then verify it isn’t in there…

And get a look at the fuel level sensors, see if there is any leaks….

The smell of fuel in the cabin is not normal… and not expensive to fix…

Best regards,

-a-

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9 hours ago, carusoam said:

Rusty tube is mostly a problem of the past…

When planes lived outdoors, uncovered…

When planes had an expected limit to their lifetime….

When fibrous insulation was left in place in contact with the tubes…

Light rust isn’t much of a problem…

 

water getting into the tubes and not draining out was a problem…

Tubes can corrode from the inside out when the plane is not cared for…

A simple cover works wonders…

:)

Read the logs, find the entry where the insulation was removed… then verify it isn’t in there…

And get a look at the fuel level sensors, see if there is any leaks….

The smell of fuel in the cabin is not normal… and not expensive to fix…

Best regards,

-a-

Thanks for the input. Insulation has been replaced so that's good. No apparent leaks so far from what I've but I still have a few other places to check

Thanks

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5 hours ago, AnAngryGoose said:

Thanks for the input. Insulation has been replaced so that's good. No apparent leaks so far from what I've but I still have a few other places to check

Thanks

Main leak point is the pilot’s window. It’s good to replace the seal every so often as it gets compressed. Water leaking here collects in the trim attachment channel beneath and rusts out PK screws attaching channel to the tubular frame and then gets inside frame collecting at bottom tube rusting it out from the inside. This is the reason for pulling the tension bolts and running a magnet inside the bottom tubes.At some point, Mooney sealed PK screws with proseal.

After removing any surface rust, repaint the tubes with epoxy primer. It’s much better that zinc chromate on steel.

Skip

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A few years ago replacing rusted tubes on a crop duster I learned that primer is not a sealer, it’s job is to prime the surface for the application of paint.

Yes two part Epoxy Polymide primer is the best primer there is but the protection isn’t fully complete until you paint the tube.

‘I’ve seen rust reoccur under primer because a tiny bit may have been left, but I’ve not seen rust reoccur when a rust convertor was used.

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