ShopTalk - November 1999

This month's ShopTalk will attempt to dispel the misunderstandings of purchasing an airplane with damage history. It seems that very few mechanics understand what to look for and even fewer buyers understand what will affect their aircraft resale value. I will address both of these issues in this article.

First, let's talk about the easy part, the mechanical aspect. As the GA fleet ages, it is getting harder and harder to find a used airplane that does not have some type of colorful event in its history. When I look at the logbooks of a used airplane I read every log entry before I look at the airplane. By doing history research and making notes of all the special moments that this airplane has been through, I can inspect the aircraft better than if I had no logbook to look at. Twenty years ago, Certified Repair Stations were only required to list their work-order number when doing major repairs, so it can often be difficult to find detailed information in the logbooks about what really happened to the airplane you are thinking about buying. The FAA frowns on this practice, so research on a newer airplane should be easier. Unfortunately, some people just don't do the paperwork properly even though this is a clear violation of FAR 43.2.

After my research is done, I know what specifically to look at. At this point, I go out to the airplane and look for clues as to how the repair was accomplished. One of the more common occurrences is the gear-up landing. On most Mooneys with a fixed step, the right underside of the wing and flap are usually saved because the bottom of the step takes all the punishment. The commonly damaged items are the bottom of the pitot tube, the nose gear doors, the bottom of the left inboard flap (because the flaps are usually down), the main landing gear door and the left brake caliper, most of the belly skins, the bulkheads that the belly skins attach to and sometimes the small fuselage cross tube under your gear-down indicator window on the floor. When a gear collapse is the cause of the incident all of the landing gear retract rods and rod ends need to be inspected for damage. Usually, a complete gear rigging with resetting the gear down lock tensions must be accomplished. Sometimes the aft bracket that holds the gear motor in place will get ground down also. Hartzell and McCauley both have requirements for a complete replacement of the propeller assembly if it was involved in any kind of in-motion strike that results in blade damage. If the engine has counterweights on the crankshafts (most do) then a complete disassembly of the engine is mandatory if the engine was turning (even wind-milling). If the engine was dead and the prop has stopped (with no prop damage) when the aircraft landed, then a crankshaft dial inspection is all the engine may need but these occurrences are very rare. A typical gear-up landing where the pilot forgot to put the gear down is usually not a big deal. The power setting is typically low and the touchdown speed is usually low.

I have seen a lot of damaged aircraft and have rebuilt many different types of airplanes. After repair, always verify that the airplane flies straight and level with your hands off the control yokes and your feet flat on the floor. The ball in the turn and bank should also be centered. Pull out the P.O.H. and check that the airplane meets book numbers for airspeed, fuel burn, and altitude. Look at the wings and see that all the control surfaces line up even with the wingtips and that the wings are level with the horizon. Just because the airplane may not fly straight does not mean it's a bad airplane, it may just need proper rigging. But don't let an improperly rigged airplane (improperly repaired) fool you. Always fly the airplane after re-rigging (as per the service manual).

When the airplane has been in or underwater, it is a different story compared with a gear-up landing. Silt and water get into everything! The engine is easy to solve, just replace it. The steel tube fuselage used in Mooney airframes is very difficult to inspect properly because water or moisture can get into the tubing. Somehow you must remove all of the moisture and treat the inside of the tubing with preservative oil. The electrical harnesses will continue to corrode over the years and cause you endless problems in almost every system. Flight controls can be drained dried but the silt in them may be impossible to get out unless they are de-skinned and cleaned. As you can see, a gear-up landing is typically no big deal but a gear-up landing in the water is a whole different story.

Another typical accident is taxing into a pole with the wing. On a Mooney, the rear spar is very strong and is seldom damaged. If you are looking at a Piper, you must check the rear spar under the back seats because it is probably bent. Mooney wing skins are stamped out in a press to set the leading edge radius, so you usually need to buy new skins. You can't easily make your own. The logbooks should refer to the 337 form for more information on how extensive the repair was. The buyer must look at when the repair was completed and how many hours have been flown since then. If the repair was finished last week, you have to ask yourself the question, "Do I really want to be a test pilot?" If the repair was five years ago with sixty hours per year or more flown you probably have nothing to worry about. That pretty much explains how the damage history affects the value. If the aircraft is flight-proven, the damage history is no more than a colorful event years ago in the logbooks and is worth no discount. If you are going to be a test pilot for the next year or two, you'd better get a healthy discount on the price of the airplane!

Always ask the seller if the aircraft comes with a warranty. This is unheard of in the used aircraft sales business, but all my rebuilt airplanes come with a full warranty. Typically, I will fly one to three years off the airplane before I sell it. By then, I have already worked out all the bugs. This is not always the case with other used aircraft sales so it is very important for you, the purchaser, to not become the test pilot. The old saying "time heals all wounds" is very true for a damaged airplane. Just be sure the flight hours are there also. Try to remember that airplanes are hand-built and the quality of the job always comes down to the person doing the job. If they take the time to do it right and take pride in their work, you will get a good aircraft. If the airplane was involved in a fire or exposed to intense heat, you can have a real problem. Aircraft aluminum is heat-treated and sometimes can be damaged but not show signs of damage. This type of airplane requires a complete inspection of all areas; not just the obviously damaged areas. I personally tend to stay away from these types of airplanes, but if repaired properly, the fire aircraft can be just as good as any other correctly repaired aircraft.

Let's take a look at how much time it takes to repair or rebuild an aircraft. My TLS is a good example of an extreme case. You will find the complete story in the March 1998 MAPA Log, but here is the Reader's Digest version. I had to disassemble the aircraft after trucking it in. The next step was to figure out just what needed to be replaced and then order all the parts. Once at this point, you can start from scratch building a new TLS using the good salvaged parts along with all of the new Mooney parts. This process took my helper and me eighteen months! Mooney can build you a new TLS in about 6 weeks on a production basis. But out in the field, the process works a little differently. The bottom line in purchasing a damage-history aircraft is to never believe what the salesman tells you. Always review the logbooks very carefully. If you think something is not quite right and you cant get a good answer from the salesman, then place a phone call to FAA registry and request all documents on file for the N-number of the airplane. Do not be pressured into an airplane you are not sure of. I tell everyone the story behind my airplane, not because I am a salesman but because I am a mechanic that takes pride in my work.

I outlined repairs from the basic gear-up slide to the extreme rebuild (my TLS). If done correctly, you can end up with an award winner just like I have (MAPA 11-97). It is a matter of time, money, dedication, and hard work. So don't be afraid of that colorful event in the logbooks, just make sure it has been fixed correctly. If you have questions about this or any other ShopTalk article, please e-mail me at shoptalk@knr-inc.com or call me at my aircraft repair shop, 307-789-6866. All ShopTalk articles can be read here at www.knr‑inc.com. Until next time, enjoy flying your Mooney.