Pre-Purchase Inspections:  WHY THEY ARE IMPORTANT & HOW I DO THEM
By : Don Maxwell
Don Maxwell Aviation
I wish this article could start out, "Once upon a time," but, unfortunately, this is a true story. Hopefully one man's mistake in purchasing his Mooney will warn others of the pitfalls of purchasing a Mooney without a prebuy inspection by a knowledgeable Mooney mechanic.

Frank had been flying for years and the time had come that he could purchase a plane of his own. Frank saw an ad on the Internet for a modified "E" model Mooney with lots of mods, a turbo-charger and long range tanks. Just what he was looking for. With the pictures and description on the net, Frank knew this would not last for long. A call to the seller and a time was set up to meet.

Not knowing a Mooney-specific mechanic, Frank called around and found an A & P that would go with him to check out the plane. Once they arrived at the seller's hangar, the plane looked every bit as good as the pictures. The owner pointed out the various mods, 201 cowling and windshield, wing tips, inner gear doors, gap seals, aileron trim, electric trim, autopilot, good radios, Stormscopes, long range tanks, low time engine with turbo-charger and intercooler.

Frank was hooked and the seller knew it. Frank asked his non-Mooney mechanic what he thought about the plane and his reply was, "Looks good to me." The deal was done for top dollar. The seller threw in an annual by his mechanic and Frank was off in the plane of his dreams.

Back home with his new pride and joy, Frank found a mechanic with Mooney experience. This is where the dream turns into a nightmare. There was a recall on the newly installed cylinders. They needed to be removed and returned to the overhaul facility. A brief walk-around by the mechanic pointed out wing damage that had been improperly repaired and a wing tip that had been installed improperly because of the wing damage. Both ailerons had been damaged in an apparent attempt to rig the controls by bending the trailing edges with wide jawed pliers.

Frank called me for some ailerons and after a long conversation, he decided to bring his plane to us to install the ailerons and to see what else might be wrong.

Frank arrived with the plane a few days later and after a quick walk around, I knew we had a major problem on our hands. The left outboard wing panel had been repaired and was now pointing up. Wing tips had been installed and on the left wing the tip and aileron were offset by 1-1/2 inches. The inner gear doors were not installed correctly and were binding against the outer doors. The trailing edge of both ailerons were squeezed nearly flat by pliers. The horizontal stabilizer had excessive travel both back and forward and up and down. Back at the rudder, again excessive up and down travel.

Removal of the tail to replace the bushings revealed excessively worn attach points requiring replacement, an expensive undertaking. Up front, removal of the cowling revealed a questionable cowl installation, unlike any I have seen before. My first thought was how did they get this approved? In the cockpit, a nice overlay had been fabricated for both sides of the instrument panel. One item that caught my eye was that the overlay covered up the original CHT gauge and oil temp gauge in the cluster. An engine analyzer had been installed and when I questioned Frank about the original gauges, he said the seller told him the analyzer took their place. Not so!

We placed the plane on jacks for a retract check, and found the gear out of specs and excessive wear through out. The retract truss on the left side was worn so bad, the gear would hang below the wing when retracted. To compensate for this the leading edge of the gear doors had been bent up to close the gap.

Having seen more than we wanted, we headed to the office to review the logs and paperwork. The folder contained all of the original logs and a mountain of receipts, invoices, STC's and 337's. Unfortunately, the STC's and 337's did not pertain to many of the items currently installed on the aircraft. The questionable installation of the 201 cowling? No STC or logbook entry was found. The wing repair? No entry. The turbo installation? A copy of a Xeroxed STC and a 337 with very vague references to the STC were found. The wastegate had been replaced by a fixed wastegate. No paperwork.

The intercooler? No paperwork. If a 337 for the intercooler had ever been received by a FSDO office, I assure you that mechanic would have received a call or visit from the Feds. The engine analyzer? No papers or log entry. If you ever question whether a 337 has been approved, you can request copies of all 337's filed from the FAA in OKC. Remember, just because there is a 337 with the plane doesn't necessarily guarantee the 337 was filed with the FAA.

So what can Frank and others like Frank do? In some cases, such as the turbo installation, he can purchase the necessary paperwork, and if the installation conforms to the paperwork, he's ok. The same holds true for the cowling, but the key word the Feds understand is CONFORMS. In this installation, I know it will not conform to the STC's that are available, and it would not pass field approval. In this case we will have to alter the installation to conform to an STC.

Well, what can you do to keep yourself out of Frank's dilemma? First, look past that paint job. My father always said, "Beware the Sherwin-Williams overhaul". Beauty may be only skin deep. When you find a plane that catches your eye, try and look past the glitter, it may cost you some gold. So much for the cliches. Weekly, I receive calls regarding prebuy's, "How much do they cost and how long do they take?" Personally, I think a prebuy should be an annual, but usually there is some time restraint that makes it impossible.

On a prebuy inspection. The first thing I do is fly the plane. I take my legal pad, and make notes as to what works and what doesn't. Does it fly straight? Is the ball centered? How does it indicate speed wise? Noise, vibration? Ground handling on takeoff and landing. Back on the ground, I take my legal pad and give the plane a good walk around inspection, I make note of signs of damage such as irregular rivet patterns and spacing, paying close attention to the trailing edge of all control surfaces. I make a list of all mods such as cowlings, closures, gap seals, tips, strobes, shoulder harness, anything that has been installed since the plane left the factory. Later on I'll check this against the aircraft equipment list and for STC's and 337's. Remember, every item that is installed on an aircraft must have some sort of documentation. Most STC's will refer you to a drawing and parts list. If you doubt whether or not a part is legal, check this parts list or installation drawing. Also, if the mod or alteration has an STC, is it the original? When purchased, most STC's are issued to a specific "N" number. If the STC does not have the "N" number of the aircraft you are considering, a call to the STC holder will tell you if the paperwork is good or bogus.

Reviewing the logs, I prepare the same as I would for an annual inspection, I take a marker pen and if the pages of the log books are not numbered, I number each page. I then note on my legal pad when each AD, Service Bulletin, major repair or parts such as Mags, fuel injection have been replaced and reference the page number. During inspections this information helps make the AD search go a little faster. I find that most owners think that mechanics just open a book or a computer program and it instantly tells us every AD for a particular aircraft. We wish. These books tell the individual AD's for the airframe, the engine, the propeller, with minimal effort. The majority of the time is researching the appliance section. This section lists AD's on mags, carbs, fuel injection, tire's wheels, brakes, seat belts, circuit breakers, transponders, batteries, ELT's standby vacuum systems, anything that is installed other than the airframe, engine and prop. So in effect, this is not one AD search per air aircraft, but four.

Back in the hangar, we continue the inspection. I check for corrosion in the wheel wells, flap hinges, and empennage. Has SB 208 been complied with?

I check the condition of the landing gear shock disc, and position of the nose gear. The prop to ground clearance should be in the 9-1/2" to 10-1/2" range. If the plane is pre-1966, does it have the new or old style landing gear disc? The old style disc are no longer available and to convert to the new style runs approximately $1900 plus labor to install.

Finally I jack the aircraft to check the landing gear for movement and operation of the retract system, followed by a thorough visual inspection of the airframe, engine and prop.

I hope this article will give you some ideas of what to look for before buying a Mooney. When you find that perfect plane, remember, take a breath, check the paperwork, and then get a prebuy inspection by someone who knows Mooneys. There are approximately 50 Authorized Mooney Service Centers in the US and countless other good shops that know Mooney's. You want the purchase of your Mooney to be a happier experience, than the day you sell it.

Don Maxwell