Pre-buys, Pre-Sales, and Consultation on Amateur Built Aircraft
Many times a pilot buying an Amateur-built aircraft isn’t certain of what to look for. Fancy paint jobs can hide
damage or poor construction. Between my building, flying, and DAR experiences I can help you decide what
is right for you and what potential problems you may see with a particular aircraft, whether they are
maintenance/safety issues, flying qualities, or even supportability problems.
Please do not get emotionally attached to the airplane until we have completed the pre-buy examination.
A surpisingly large portion of the airplanes for sale will not pass a pre-buy examination. I have performed
hundreds of these examinations over the years and can help you make an informed purchasing decision.
I am recognized as the go-to guy for pre-buys, especially on RV-type aircraft. I've traveled all over the
USA (30 States) via airlines or RV-10. Every single customer will tell you it was worth it, and sellers have asked me
to do their next pre-buy examination. Both the seller and the buyer win, as we will all understand the quality
of the aircraft along with any potential safety items that need to be fixed.
It does appear that some types of airplanes are getting snapped up as soon as they are presented for sale.
Don't fall into that trap. There are gems, but be patient and together we will find the right aircraft for you.
All of my customers will tell you it is money very well spent.
As for RV's, all of them really need a prebuy examination, especially the earlier models that were not
prepunched (RV-3, RV-4, RV-6, RV-6A, and early RV-8's). The later models such as the RV-7, RV-7A,
RV-8, RV-8A, RV-12, RV-10, RV-14, and RV-14A, were pre-punched, but still need to be checked for proper
assembly and Service Bulletin compliance. All of them have some very critical areas requiring examination
of proper building technique.
See my article on Pre-buy Inspections in the Kitplanes October 2014 issue and the updated articles in
KitPlanes July & August 2016. The 2014 Article is at the end of this web page. I recently examined an RV-10 kit
advertised as 95% complete. The riveting was so bad throughout the entire aircraft that it is a restoration project.
The buyer dodged a big bullet on this one. Unfortunately, a first-time buyer purchased this kit a few months later without a prebuy examination. He got a second opinion, confirming my results. He was out $35K.
needs, and types of aircraft you are interested in.
time in the future. This examination is to help you make a purchasing decision.
in order to command a fair market price. About 50% of the airplanes I examine end up not being bought due
to the list of discrepancies discovered during the pre-buy process. Almost all of them are fixable, but it tends
to delay or even sour the prospective buyer on the airplane. By getting this examination completed before you
even list the aircraft you are way ahead of the game, and I will talk to any prospective buyer for you. It will
certainly shorten the sales cycle for you, and perhaps even command a higher price.
Thank you Vic! I'm very glad we decided to take it to an expert for this inspection. You don't know what you don't know and we trust our lives to these machines. Good to have someone who really knows them do a proper inspection!
-Ian C (Alabama)
I hired Vic to complete an inspection on an RV-10 prior to purchase and from my perspective the plane was in great
shape. Vic flew to the home airport of the plane and did a very thorough inspection, checking areas that I would have
never thought of looking at since I had not personally built the plane. He advised me that this plane needed much
work and was concerned with the craftsmanship. Based on his advice, and what he showed me in the visual inspection, I did not purchase this plane. I am so glad because the owner had to spend several thousand dollars to get some of the items on Vic's report corrected for safety reasons.
Vic's services did not stop there. He got on the internet and looked for other RV-10's, unbeknownst to me and
called me a couple of days later and said that a RV-10 had just become available, looked great and recommended someone
on the west coast that could go do a visual inspection right away. That very night I made a conditional offer, set up the inspection
and bought my ticket to fly out and pick it up if all worked out well. I now own this almost perfect RV-10 and love it!
I have called Vic many times over the last two years for advice and he has always willing and able to help me out. He is a master
at Advanced Flight Systems, The Garmin GPS systems, and avionics. Having built many RV's and mastering incredible panels, he is the go to
person for advice.
I would highly recommend Vic's services to anyone.
-John P. (South Carolina)
I recently sold my RV-10 aircraft. As we all know an important aspect of any aircraft ownership change is the pre-buy inspection.
In my case the pre-buy inspection was done on behalf of the buyer by Vic Syracuse of Base Leg Aviation.
Vic’s inspection of my aircraft was thorough, and efficiently completed. The result of his work was instrumental in the sale being completed smoothly.
I believe the buyer is confident he is getting a good airplane and I am confident he is in good hands as he becomes safely acclimated to his new airplane.
I can without reservation recommend Vic to anyone looking for someone to complete a pre-buy inspection or any of the other many services offered by Base Leg Aviation.
Kitplanes Article from October 2014:
So why do I need a pre-buy inspection, you ask? You've already seen the airplane, you really like the paint scheme and the panel has most, if not all, of what you want. And you went and flew it for 30 minutes and she handled great! I would ask how many of you got married after one date, but I fear there is always one who would raise his/ her hand. Instead I will share with you some of my thoughts on the need for a pre- buy inspection and why I think they are becoming even more important as time passes on. Then you can decide if you should take this step prior to buying. Remember, we're supposed to be having fun here, so no so sense taking the beauty home only to find out it wasn't all that we thought it was.
My experience has led me to believe there are 3 critical areas that need to be closely scrutinized: the airframe, the engine compartment, and the aircraft wiring/plumbing. And each area has it's own areas of specialty. And to accomplish a good prebuy the aircraft should be opened up as if ready for a Condition Inspection, and performed by a knowledgeable and experienced person relative to the specific aircraft.
I like to start with the airframe, which is a little different than in the Certified world. Why? Because Amateur-Built aircraft aren't built on assembly lines where we can be reasonably sure that everything aft of the firewall is the same. Here we can be reasonably assured that every aircraft IS going to be different. And a good place to start is with the tail, as that is where the builder usually started, and this is where you can see how the progression of skills begins. There are some critical holes in the tail that don't leave a lot of room for proper edge distance if not done carefully. I have seen some tails on aircraft that had boltholes mis-drilled and covered up, and some even missing bolts and/rivets. I have seen one that I thought was not even airworthy enough to be flown home. I had one customer whom I really felt sorry for, as he had purchased the aircraft sight-unseen. It took him a while to make things right but eventually it sold. The rear spar bolts are another very critical area to check for proper edge distance. I think it is important to check and see if the aircraft has been built according to plans, or if there have been any modifications, especially those that might affect the structural integrity, such as drilling holes into longerons for equipment without adhering to edge distance rules, or removing too much bulkhead material behind the instrument panel to fit all of the wiz-bang equipment.
The landing gear is another area to check, especially if the airplane has been routinely operating off of grass or unimproved strips. These types of operations do take a toll and lead to cracks in weldments and wheel pants brackets, as well as corrosion due to the moisture from dew or wet grass. A good cleaning followed by and inspection with a bright light and magnifying glass will usually do the trick here. On fabric aircraft the age and type of fabric, as well as the covering process should be considered. With regards to composite aircraft, checking for bad bonds and/or possible delamination in structural areas should be a high priority. Again, an aircraft-specific knowledgeable person is critical.
When it comes to plumbing, wiring, and systems, my experience has shown that these aren't really the strong areas for a lot of builders. The proverbial rats
nest of wiring can make it difficult to chase down problems, and sometimes is the source of unexplained gremlins, such as instrument gyrations when the microphone is keyed. It seems not everyone understands that the rubber motor mounts not only dampen the engine vibrations, but also electrically isolate the engine from the airframe thus requiring a bonding strap from the engine to the mount/ firewall to insure electrical continuity. And just because the bonding strap was initially installed doesn't mean it is still intact. It needs to be checked regularly for structural and electrical continuity. I really like it when I see two bonding straps. :)
Sometimes I see prospective buyers thinking they are going to buy a cheap airplane and spend money upgrading the panel, not realizing that it could take a substantial amount of rewiring, sometimes having to replace all of the old copper automotive wire with aircraft grade wiring and proper grounding in order for the new stuff to work properly. Sad to say, but electrical systems do not seem to be a strong point for many builders. And the simple electrical needs of the early VFR-only aircraft are a far cry from the requirements of all-electric glass panels and entertainment systems in today’s aircraft. Wire routing, antenna distances, and grounding are so much more critical to insure proper performance and reliability.
I'm also seeing a common theme among the older types of aircraft, especially RV's. Early RV kits were a far cry from the pre- punched kits of today. And many of the pre-punched parts in today's kits actually had to be made out of raw materials, requiring more refined metal-working skill sets as well as an understanding of the various types of metals and where and how they could or could not be used. I don't mean this as disparaging in any way, but I think the last generation was more frugal when it came to aircraft building. It was a generation with not a lot of extra spendable income, so build times were longer and there were many trips to OSH scrounging for the deals in the Fly Market. I know. I was one of them! I'm seeing this show up now as the fleet ages and many of builders are selling their airplanes. I see a lot of surgical tubing behind instrument panels that has become very brittle with age. When used in vacuum systems it is a recipe for disaster. I've seen hoses with date stamps of 3Q 76 going to oil coolers. Sloshing compounds in wing tanks are also a prime candidate for problems.
The bottom line on the airframe is to make sure it is solid. While all things probably can be restored to flying status with some time and money (Glacier Girl is certainly a prime example), most likely you are not interested in a project. Fixing a poorly built airframe can take a lot of time, unlike an engine compartment, which can be completely replaced in a couple of days.
Speaking of the engine compartment, let's zero in on some prime candidates in this area. Certainly a compression check and a visual/sensory check of the oil, as well as cutting open the filter, should be mandatory. Lots of kudos here for builders/owners who have had the aircraft on an oil analysis program! Looking at the spark plugs will also yield some clues as to how the fuel and ignition system are working, as well as some insight regarding internal cylinder health. Are they oily? Worn? Lead fouled? Be sure to check the baffling for security and cracking, the engine sensors for proper mounting and the oil and fuel hoses for age and wear. Don't forget to check the propeller leading edge as well as the spinner, and especially the spinner bulkheads for cracks. And here are a couple of things that routinely get overlooked: the carburetor or fuel servo inlet screens, the gascolator screen, and the oil sump screen. I had one original O-320 (no dash number) on an rv-6 that still had the original blue paint on the oil sump screen AN-900 crush gasket. Hard to believe but it appears that I was the first one to remove it in many, many years!
The rubber motor mounts are also an area that needs looking at for 2 reasons: they do age and some builders used less-than-ideal rubber mounts for the initial installation. I've replaced a number of these with real Lord mounts and the owners really notice an improvement with regards to engine vibration.
In the end, a list of discrepancies should be presented to the prospective buyer, and any potential safety issues should be discussed with the current owner. Some may need to be fixed right away, and some may be able to be addressed in hue he future as a budget allows. Either way, everyone is more informed, and hopefully the flying fun can begin!
Kitplanes CheckPoints Column by Vic Syracuse September 2016 Part I
I was in the process of performing a pre-buy inspection on a high-priced RV-7 that the builder/owner had flown to my place. I think I actually felt a rise in my heart rate when I noticed that the horizontal stabilizer was not even properly bolted to the fuselage. I queried the owner about doing aerobatics and he said, "All the time!" I decided I wanted his guardian angel, and that episode, amongst others, keeps prompting me to help educate our readers with regards to pre-buy inspections. This month and next I'll show you some insight on a methodical approach to buying an Amateur-Built airplane. I'll even intersperse it with some stories that will make you want to laugh and cry at the same time.
Vic Syracuse inspects Bruce McGregor's RV-12. It is really important to check the continuity of the control system, along with any known wear areas.
Why Do a Pre-buy?
It seems as though the continuing improvement in the economy has positively affected the aircraft market, and I've been busy doing pre-buys, especially on RV-10s. I want to share with you a sampling of the egregious things I am seeing for a couple of reasons.
First, as owners and operators of Amateur-Built aircraft, we don't yet have a repository of information where we can all seek out service difficulty reports. While builders are usually aware of the numerous forums and type clubs, and know how to retrieve and share information on their particular model (VansAirForce.net and the Matronics email lists are two such examples in the RV world), typical second owners who are not involved in building usually are unaware of these resources. If the buyer comes from the certified world, where they are used to having an A&P take care of their airplanes, they assume the A&P will do the same for their Amateur-Built aircraft. Now a licensed mechanic in lieu of the repairman certificate holder will perform the condition inspection. However, the mechanic may not be aware of the intricacies of homebuilt aircraft. As a member of the EAA Homebuilt Aircraft Council, I can tell you that we have identified such a resource as a high-priority item and are working to create one in the near future.
The tail section can usually be a good view into the rest of the airplane. Hopefully these crooked rivets and poor edge finishing did not continue throughout the rest of the project.
Second, in a past column I mentioned that I am really an advocate of a task-based Phase I, instead of the current hours-based Phase I that we are all familiar with. These have been pioneered and proven by some of the ELSA manufacturers, with the RV-12 being a great example. I am seeing a rapid rise in the appeal of the RV-10 to the non-builder market. When compared to the cost of any new certified four-place single-engine airplane, the RV-10 is about one-third the price and has almost the same capabilities. Consequently, a number of them are being sold immediately after the 40-hour Phase I completion. These aircraft are being presented to the new buyer with some very serious problems. I know I am seeing a small cross section of the available aircraft, but of late I have been looking at airplanes all over the USA, and I am a little concerned that the deficiencies are a widespread problem.
Personally, I think signing off an airplane with known problems borders on unethical, but a bigger concern is that someone might get hurt. In the case of an aircraft like the RV-10, we are talking about families, perhaps even unsuspecting families. Not right and not fair. I am a huge advocate of Experimental aviation, but the time and place for experimenting is without passengers. Here are a few examples and some ideas for a pre-buy checklist you might be able to use.
An inspection mirror and bright flashlight can be your friend and help you see critical areas for construction quality.
Missing Fuel Pressure
One recent and very interesting phone call I received was from a new owner who said his fuel pressure was indicating zero. Upon further inquiry, he couldn't remember when he first noticed it was missing (yes, missing), as he had just spent about 8 hours in the airplane flying it back to its new home. In the process of sitting in the airplane to understand the glass cockpit, he configured the fuel pressure to be added to the display, where it now read zero. Since this was an injected engine, I had a high degree of confidence that his fuel pressure was not really zero, as we verified the engine ran just fine at full power. He proceeded to fly to my place, and upon arrival, I quickly removed the top cowl to verify the type of fuel pressure sender. It was clearly of the 12-volt variety, and a quick check with a voltmeter verified the presence of 5 volts. Yep, 5 volts! I then checked the engine monitoring system and verified it was in fact wired to the 5-volt supply instead of the 12-volt supply. A quick rewire to the 12-volt supply and it now displayed the proper fuel pressure. A phone call to the builder confirmed that it had never worked, so he had in fact deconfigured it from the display! In my wildest dreams I cannot imagine making even one flight in an aircraft with a fuel-injected engine without the fuel pressure readings, let alone flying for 40 hours and then signing it off. Fuel pressure is a checklist item in every injected engine I have flown. I think some of us are keeping our guardian angels working overtime!
The vertical fin cap on this RV-10 stuck out over 3/8 inch and acted as a fixed trim tab. The forces in cruise were so strong that the pilot's leg would cramp after 20 minutes.
In another case, an aircraft that had been flying for 500 hours over a six-year period exhibited some pretty serious wiring issues. The GPS steering information never presented itself to the EFIS, and the VOR/ILS information was only partial and, in fact, appeared to be reversed. The right-wing strobe light came on when the nav light switch was activated. The builder/owner said he was aware of the erroneous indications and operations, and was frustrated with them, but had learned to fly the airplane just by looking at the moving map. Quite honestly, if I hadn't thoroughly checked the avionics as I usually do during the pre-buy inspection, it could have been very confusing for the new owner.
The vertical fin on the RV-10 and most rear spars on wings require a castellated nut and cotter key due to the movement caused by flight loads. Far too many have an AN365 stop nut.
High Oil Temperature
The last example came from a conversation with a builder/owner regarding engine-operating temperatures. The comment was made that the engine temps never go into the "red." As most of you know, with our new glass cockpits, we can configure the temp ranges anywhere we wish. I know some people who just keep changing the numbers until the alarms go away! When asked for actual numbers on oil temps, the reply was that it usually runs 205-239°F in cruise. Yikes! I know redline is 240° for this particular Lycoming engine, but is there really a difference between 239 and 240? Take a look at the tolerance on the engine sensors and you might be surprised. I politely explained that it really wasn't operating in the normal range for the majority of his type of aircraft out there, and that he might want to take a look at it. He graciously agreed, thankfully.
Here's an example of a misdrilled and poorly attached vertical fin, coupled with two different sizes of nuts and four washers on one bolt alone. Max should be three, or else use a shorter bolt.
The Inspection Process
One of the first things I tell every prospective buyer is that they should not get emotionally attached to any particular aircraft until we have performed the pre-buy inspection, and that they should be prepared to be disappointed. Sometimes we hit it right on the first try, but about 50% of the aircraft I inspect fail to meet expectations. While there is usually a buyer for any aircraft out there, typical non-builders coming from the certified world want an airplane they can immediately hop into and go fly, so mechanical soundness, build quality, and avionics capabilities are paramount. Most aren't looking for a project.
Let me explain my role in this process. I make it clear that I do not accept any commissions from the buyer or the seller. I am paid for the pre-buy. I will not represent any aircraft. I wish to be the objective third party who can ensure that the aircraft is safe and is as represented. When asked, I will advise on what current market values are as observed from the completed transactions I have been involved with. Rarely do they match the posted prices in the various sales publications or web sites. I am not here to drive the price up or down, as it really makes no difference to me. However, most airplanes end up getting pretty close to a condition inspection in the process, and all owners are very appreciative and work to rectify any discrepancies, even if the current sale should fall through.
Hidden underneath the "spacer" was actually a binocular shaped hole formed from two holes drilled too closely together.
So, let's get started. Most of my questions begin with trying to understand who actually did the initial construction, how it has been maintained and operated, how it is equipped relevant to the buyer's needs, and has there been any damage history. If we can get past the phone conversation, we usually then try to schedule a mutually convenient time for all parties to meet. Yes, sometimes a phone conversation will determine that the aircraft will not meet the needs of the buyer, and in a couple of cases the prospective buyer was even told that it wouldn't pass if you were bringing Vic Syracuse. While that might be good for the current buyer, I hope another buyer is just as willing to seek out real expertise prior to purchase.
Look closely and you will see two open holes on the left side. They require AN4 bolts and have been found to be missing in far too many RVs.
What do I mean by real expertise, you ask? Don't forget that these are Experimental aircraft and are mostly built by amateurs. Even with as many airplanes as I have personally built, I still consider myself an amateur and very much capable of making mistakes. I know, as I've seen me do them! Just because someone has built one aircraft doesn't qualify him or her as an expert on inspecting one built by someone else. Who's to say his/her aircraft is built correctly? Find someone who is really experienced on the specific type and has a good reputation. Good examples are DARs, EAA technical counselors, and qualified "repeat offenders"—builders who have completed more than one project. Most, but not all, of my experience is on the Van's and Kitfox series of aircraft, so much of my focus in this series will be centric to those, but the inspection process is applicable to most other aircraft.
The bolt into the longeron did not meet the minimum edge distance required. Van's provided an engineering fix that should be trouble free and much stronger.
I am going to separate the inspection checklist into four distinct categories: airframe, engine, avionics, and logbooks/documentation. I usually start with either the engine or airframe, depending upon the builder's experience, as well as what I've already gleaned from the initial phone conversation. A good place to start is at the tail. This is where most builders begin construction and develop skills used throughout the rest of the construction process. In the case of metal airplanes, it is easy to see misdrilled or improperly placed holes and overdriven rivets. On composite airplanes look for poor or sloppy layups. For tube and fabric aircraft, welding skills are really put to the test around the tight tubes and clusters in this area. Fabric covering skills are also put to the test here, with all of the sharp bends around small tubes. It is also a view into the builder's application of best practices such as the use of torque seal on bolts and jam nuts.
Loose jam nuts on control rods are a too-common occurrence, even on airplanes that have been flying for a while. They should be tightened during final assembly and then marked with torque seal.
Review the Plans
Be sure to familiarize yourself with the aircraft plans. As an example, some aircraft in the Van's series require a washer in the vertical stabilizer attachment on one side to offset the vertical fin. Some of the vertical fins, like on the RV-10, require the use of a castellated bolt and nut on the forward fin attach, much like the rear spar, due to the movement of these structures imposed by flight loads. About half of the ones I inspect are improperly secured. Loose jam nuts on the rod end bearings are another common finding and, in fact, have even generated a service bulletin by Van's Aircraft. Over time the loose jam nuts will cause cracking of the flight control spars if not caught. So far my record stands at finding 12 loose jam nuts on a single airplane! Torque seal can be your friend here. If there's no torque seal, better get the wrench out.
Don't forget to inspect the airplane either before or after it is disassembled. This misalignment can cause cooling problems with the engine, as well as reduce power.
Check the Controls
While at the tail, it is a good time to check for complete and full control movement. Here again, I am amazed at the number of airplanes that have problems in three particular areas relative to flight controls:
Control surfaces that bind prior to reaching full deflection.
Controls that do not even reach full deflection due to improper rigging or interference, of which improperly installed autopilot servos are the biggest contributors.
Reversed trim, which comes to light in about 30% of the inspections for new aircraft. However, I inspected one aircraft that had been flying reversed for seven years, and the pilot stated he had just become used to it. I promptly rewired it for him on the spot, and he was very appreciative.
In a couple of cases, I actually had to argue with the builders long enough that I questioned out loud if they were really pilots. One builder tried to convince me that the stabilator trim on an RV-12 worked in reverse because it was a stabilator. Huh?
In the case of a Storm 320E, which happened to be the first kit completed in the U.S., I was uncomfortable with the five degrees of up elevator travel. Enough experience building model airplanes and real airplanes told me that five degrees just didn't seem like enough, especially if needed to break a bad flare in this nosegear aircraft. We both agreed that a call to the manufacturer was in order, and sure enough, a more reasonable 15 degrees of up elevator was specified, requiring an adjustment of the stabilator pitch and antiservo mechanism.
Wherever a bolt is subject to rotation, it is best to use a castellated nut and cotter key, especially here at the rudder cable attach points.
For taildraggers, pay particular attention to the tailwheel. It's usually fairly easy to lift it off the ground to perform a thorough inspection and should be done regularly. Check for loose or worn wheel bearings, improper spring tension, proper lubrication, and sound structural integrity where it attaches to the fuselage. I've seen many center-locking tailwheels fail prematurely due to improper lubrication.
From the tail, inspections usually progress to the tail cone and/or baggage area. In the past one could expect to find only ELTs and strobe power supplies behind the baggage bulkhead. It is much more complicated today. In well-equipped airplanes remote avionics such as ADS-B receivers and transponders are the norm, and sometimes they even include air conditioners and complicated battery backup systems. On top of the complexity, they are installed in areas that don't normally receive inspections during the course of a year, and can also have an adverse impact upon the aircraft CG. It is typical for me to find loose jam nuts here, especially on the autopilot servo linkage, as well as missing safety wire or lock washers on the servo bolts. It is also important to check that the autopilot linkage does not allow an over-center position when the controls are moved throughout their full deflection. While back there, take a close look at the static system to insure it is routed properly to avoid any potential water collection.
ELTs need to be checked for proper operation (during the first 5 minutes after the hour), and the battery needs to be checked for replacement dates. The required annual logbook entry for ELT checks is the most often missed entry that I see. I see a fair number of inoperative ELTs, and in one case during a condition inspection, the ELT was discovered to be completely missing! By the way, this was on an airplane that was sold after 25 hours to a non-builder. The new owner had been unknowingly flying her newly built RV-9A all year without an operative ELT. Not cool.
Be careful to ensure that autopilot servos will not travel over center when the controls are fully deflected. One aircraft had intermittent jamming due to this condition.
Inspecting the Wings
Next, I move on to the wings. There are a couple of critical areas here, not the least of which is their attachment to the fuselage. After all, it's not really an airplane without wings, so we might want them to stay attached! Here again, it is important to understand the designer's intentions and directions. In the case of the RV series, so many people have forgotten to install four bolts into a particular wingroot spar location that Van's has recognized the need for a service bulletin. And just as in the forward attach point of the RV-10 vertical stabilizer, the rear spars require the use of a drilled bolt and castellated nut due to the movement on the rear spar caused by flight loads. About 20% of the aircraft I inspect erroneously make use of fiber lock nuts here. I have come to the conclusion that by the time builders mount the wings at the airport, they are no longer referring to the plans, either due to overconfidence at that part of the journey or due to the fact that the plans were left at home during the move. Airplanes such as the RV-12 and Kitfox series, with removable wings, need to be closely inspected for proper security of the attachment hardware.
Most of you already know this, but just in case, do remember that the red nav light goes on the left wing, and the green one goes on the right wing. Yes, I inspected one airplane that had them reversed!
Flight control freedom of movement, along with the proper amount of deflection, needs to be verified. The flaps also need to be checked for proper operation, and in the case of electric flaps on the Van's series, there is a service bulletin detailing the requirement to drill and safety wire the flap actuating motor, another often-missed item. While underneath the wings look through the inspection panels to check for corrosion, especially on airplanes that have been repainted. Sometimes the stripper can run down inside the wings and cause problems, as can Alodine when not appropriately rinsed.
While under the wing it is easy to check the pitot tube for proper mounting, and for proper operation in the case of heated pitot tubes. While having someone apply aircraft power with the pitot heat turned on, you can usually feel the tube begin to warm up. Don't forget to turn it off quickly. I also check the landing gear while I'm already squatted on the floor for the wings. Most homebuilts, and even some certified airplanes such as the Grummans, Cirrus, and Columbias, make use of a castering nosewheel for ground steering, requiring attention in a couple of areas. Brake wear is usually high in the initial hours as the pilot gets used to the free-castering nosewheel, and the breakout force of the nosewheel needs to be properly set according to the manufacturer's specifications. If left unchecked, brake pad wear can get to the point that it allows the actuator puck to deploy far enough out that the o-ring seal is broken, followed by loss of brake fluid and braking ability, the results of which can lead to bad consequences. It can take some discipline by the operator to regularly remove tight-fitting wheelpants in order to carefully inspect the brakes. I highly recommend this to new owners.
This pitch servo is mounted without the use of locknuts or safety wire.
Missing Cotter Keys
I'll leave you with another sad-but-true experience with one RV-7. I noticed that neither wheel had a cotter key installed in the axle nuts. When I pointed it out the builder stated, and I quote, "We really cranked them down and have already performed our taxi tests. They aren't going anywhere!" Yikes! Better get some new bearings on order soon.
Next time we'll continue with the wings, engine, and paperwork. If any of you just have to buy your airplane between now and then, send me an email and I'll work up a checklist for you.
Kitplanes CheckPoint Column by Vic Syracuse October 2016 (part II)
I know you have all been waiting for the second part of my pre-buy article so you can run out and perform your own inspections. Based on the example of a customer who brought his RV-10 to me for a panel upgrade, I hope you will still seek out experience to help you. In this case, the customer had paid for a pre-buy and was told the wiring was fine. I removed solid copper Romex house wiring with screw splices in multiple places and ended up rewiring the entire aircraft! So, hopefully you've been patient with your purchase since last month and we can continue our education.
Finishing the Airframe Inspection
Continuing where we left off, the forward tank attach fittings on the Van's series are another area that requires some attention, as they must be built to provide both some measure of safety in the event of an accident as well as security from movement during normal operations. This is accomplished by a slot in the physical attachment, along with the use of drilled-head bolts tightened into a nut plate and then safety-wired. Depending on the vintage of the aircraft, some have slots cut by the builder into fabricated aluminum attachments, and the newer ones have metal pre-stamped parts with the slot already cut. One aircraft made a strong "pop" right at takeoff (yes, very unnerving) until we discovered the forward attach fittings were loose. We were able to duplicate it on the ground.
Don't forget to take the time to either remove the wheelpants or use a bright flashlight to look for cracks in the brackets.
Speaking of fuel tanks, many builders forget to label the caps with the type and amount of fuel.
The last things to closely inspect on the airframe are the landing gear attach points. In the case of a retractable-gear airplane, a retraction test on jacks is a definite requirement.
The flap actuator seen here, and used on many varieties of aircraft for flap and trim actuation, requires safety wire between the housing and the bolt in case the locknut should come loose.
Van's has issued a number of service bulletins pertinent to the landing gear on various models, and it is wise to pay attention, especially if the aircraft has been routinely operated off of grass and at high gross weights, both of which can induce cracking on the engine mount weldments. A bright flashlight is our friend here.
On aircraft with bungee-cord shocks, pay attention to the age of them, as they are usually life-limited.
Deformed pitot tube. Surely we can do better than this for a device that is so critical.
Once I am satisfied we have a sound airframe, it is time to move onto the engine compartment. This is the area where the builder usually receives the least guidance from the kit provider. Many do not even know where to look for service bulletin or airworthiness directive applicability to their engine. A fair number of them do not understand that there is an oil screen on the engine, along with a fuel inlet screen on carburetors and fuel servos, that need to be checked and cleaned regularly.
Look closely and you will see a very common crack on the rear baffling that is used to support this oil cooler.
I like to understand the history of the engine before I even start looking at anything, and also inquire as to whether or not it has been on an oil analysis program, especially for an aircraft that is infrequently flown. The worst-case installation I inspected had an engine that had been removed from another aircraft and had not been run in at least 20 years, and the hoses were approximately the same vintage. This engine was installed on a high-performance Lancair aircraft, with the planned initial test flight on a 3000-foot runway. I politely persuaded the builder that it was really a risky endeavor, and it might be wiser to have the engine fully inspected or torn down prior to the first flight.
The forward tank attach actually moves, much like the rear spar, and calls for a drilled-head bolt and safety wire.
By the way, some safety advice here: Be sure to verify the ignition systems are turned off and ask when the last grounding check was performed. If unsure, assume the ignitions are hot and be very careful around the propeller arc until the spark plugs have been removed. Ask if the fuel system has been modified in any way and if it has been flow checked to exceed 150% of takeoff power.
Many builders are surprised to learn that the rear spars actually have some movement on them due to flight loads and require a castellated nut and cotter key.
Looking for Clues
Sometimes it is fun to play Dick Tracy. On one RV-10 with a nicely painted engine, I noticed that one of the bottom spark plugs was a different manufacturer than the other five. By itself this shouldn't be a problem. Someone could have dropped a plug, and this was the available replacement. But I had to ask. The owner feigned ignorance, but upon later inspection of the logbooks, I found an entry that reflected a cylinder replacement due to damage from a hangar collapse! Interestingly enough, there weren't any details as to cylinder break in. On the same aircraft I noticed the scat tube to the firewall cabin heat box was actually touching an unprotected area of the main fuel line. I asked if they noted any anomalies of fuel pressure during flight or ground operations, especially since they were based at an airport with an elevation of 6000 feet. Not unexpectedly, they were experiencing vapor lock unless the electric fuel pump was left on. I showed them the likely cause and how to rectify it.
A thorough inspection of the engine compartment can yield clues as to abnormal operating temps. Hotter than normal temps can usually be noticed by brittle hoses, especially the Lycoming intake hoses since they are so close to the exhaust systems. Intake gaskets can also become brittle and leak. Telltale signs are usually a blue fuel stain at the top of the intake tubes and high EGTs when the throttle is reduced for landing. The gaskets are fairly easy to replace, and I've had more luck with longevity using the red Superior gaskets as opposed to the original Lycoming black ones.
Never, ever use RTV around fuel or oil as it can dissolve and get into the system.
Engine Controls, Baffles, Seals, and Exhaust
A surprising number of aircraft I have inspected have less than full movement of the engine controls, with the throttle and the mixture being the highest offenders. Most of the arms on the fuel servos and/or carburetors can be drilled with a new hole to allow complete movement from stop to stop. On one particular RV-8 the owner was telling us how fast it accelerated at takeoff, and how he "really had to hold on." I showed him he had at best 2/3 of full throttle movement on the fuel servo. This was after flying 240 hours and four years, so it was missed on multiple condition inspections. I couldn't help but wonder if the cylinders were properly broken in, but I did tell him to expect even more acceleration on the next takeoff!
High EGTs at idle and rough idling engines can be caused by leaky intake gaskets or, as in this case, a missing bolt.
The baffles and baffle seals need to be inspected with careful attention paid in a few areas. The baffles must be sealed to the engine (high temp RTV works well here), they must form a tight seal to the upper cowling, they should be free to move between the cylinders, and they must be inspected thoroughly for cracking if they are supporting any weight such as an oil cooler. Attaching an oil cooler to the rear of the last cylinder is a common practice, but I don't like it. It invariably will lead to cracking of the baffling and oil cooler supports. You will find all kinds of information on various forums and boards on how to add cross-members to the engine in order to support the cooler, but if you've ever seen some high-speed photography of cylinder movement while the engine is running you will realize the futility. Besides, I don't really think it is good to be tying the cooler to other parts of the engine that are not moving, such as the crankcase. Picture a wet dog shaking water off. Get the idea? On the other hand, oil coolers mounted on firewalls rarely have any cracking problems. Don't forget to inspect the upper and lower engine cowlings. Check the top cowling for signs of baffle rubbing. It will not only eventually rub through the cowling, but it is a good source of engine vibration transference to the airframe. The lower cowling, if not properly protected by heat shielding and some form of epoxy paint, will usually show signs of heat and oil damage.
This hot air duct is way too close to the unprotected part of the fuel line and, in fact, was causing vapor lock for the owners unless the electric fuel pump was left on. Better routing or fully covering the fuel line with firesleeve should help.
Exhaust systems need to be checked for proper mounting and to ensure there are no cracks, especially in welds or under heat muffs. Regular application of mouse milk on all exhaust joints is a really great preventative measure, and I apply it anytime I have the cowling off on my own aircraft. Be sure to check the exhaust nuts and gaskets at the cylinder attach points. Magnetos should be checked for proper timing and in the case of Slick magnetos, compliance with the 500-hour service bulletin.
Alternator and Engine Ground
The alternator is another item that requires some attention. Just as the engine has a very big job to do, so does the alternator. It must be capable of supplying ample power to recharge a battery after starting the engine and then continue to carry the full electrical load of the aircraft. Today's all-glass cockpits can require steady state 25–30 amps during the daytime and rise to 40–50 amps at night with the pitot heat activated and lights illuminated. It is important to have the proper size wire with very secure connections, along with an engine ground of the same size or larger than the starter wire. On one very nicely equipped RV-10, there was a 14 AWG wire being used as the main feed from the alternator. It was not only improperly sized, but also a potential fire hazard, as it was attached to a 60-amp alternator breaker. Clearly, the wire would have melted before the breaker could have activated.
Alternator wires should be adequate to supply the full load from the alternator. Normally an 8 AWG or 6 AWG wire will work—definitely not a 14 AWG as discovered here.
Also check the alternator belt for proper tension and any signs of wear, and the pulley for alignment with the flywheel.
Many builders forget to attach a ground wire to the engine, assuming that bolting the engine mount to the firewall takes care of that. Little do they realize that the rubber engine mounts, which help to isolate the airframe from engine vibrations, also electrically isolate the engine. Alternators will not work without a good ground, and an improperly grounded engine can also cause the instrument senders to be very inaccurate. Bad or improper grounds are usually first noticed by poor cranking during starting, the initial reaction being that the battery must be bad. The engine should be grounded to the firewall via one or more flexible cables.
Spark Plugs and Prop
Upon removing the spark plugs for a compression check, perform the usual inspection and look for worn, oily, or lead-fouled plugs. They can be indicators of improper operation such as ground leaning, and other problems such as poor sealing piston rings. I always perform the first compression test on a cold engine, as engines that are flown regularly and properly cared for will usually have compressions in the 70s. Sticky or leaking valves and rings are easier to find on a cold engine. If anything is out of the ordinary, I will then run the engine to see if the problem clears itself. If not, further investigation is warranted, and in the case of a sticking valve or continued low compression, follow-up might be immediately required.
Here is a real example of a low compression test that resulted from a sticking valve. Lots of air could be heard coming out of the exhaust pipe.
Don't forget to check the propeller and spinner for proper mounting (regular seasonal torquing of wooden propellers is especially important), leading edge damage, and proper lubrication intervals for certain constant-speed propellers. If the assembly has been dynamically balanced, make sure the weights are still attached. The proper size and location of them should be found in the aircraft/propeller logbook. Constant-speed propellers also have a recommended TBO, and it should be checked. Sometimes it is necessary to remove the spinner to check for proper safety wire. Speaking of safety wire, there are lots of places in the engine compartment that need safety wire, and often it is missing.
Removal of the spinner disclosed this disaster waiting to happen. The forward bulkhead was severely deformed due to over-torquing of the propeller bolts on a wooden prop.
On aircraft with Rotax engines there are some inspections required for the gearbox that should be checked and recorded, and there have been numerous service bulletins regarding carb floats and fuel pumps that require compliance.
Avionics and Controls
Now it's time to look at the avionics. While current databases aren't actually required, it is another indicator as to whether the airplane really is flown regularly. I like to take my Michel avionics tester to pre-buys. It enables me to verify proper operation of any VOR/ILS, audio markers, com radios, and intercoms. In one case I discovered very weak volume on the com 1 audio, which was caused by a ground short on the wire to the audio panel. An improperly assembled back plate connector on the rear of the unit was the culprit.
Ever wonder why some of those engine sensors are intermittent? Here's a good example of unsupported wiring that will eventually lead to failures.
Once in the cockpit, a thorough check, much like what is performed during a preflight runup, can highlight any problems. A potential safety area I often see in amateur-built airplanes pertains to control movement. Flight controls need to move throughout their entire range of motion without interference. I've seen many control sticks, especially on RV-10s, that will activate switches when moved to the full-forward position. I often wonder who performed the initial airworthiness inspection, as control stick interference should be disqualifying.
All controls and switches should be appropriately labeled. Imagine your passenger pulling this knob back just as you start your takeoff climb—yes, it was connected to the throttle.
Here's an example of an unlabeled button potentially having serious consequences—the green button on the stick grip was the starter button.
Another problem area pertains to controls, switches, and circuit breakers that aren't labeled. The worst one had an unlabeled starter button on the control stick. I did manage to convince the new owner to remove it before a propeller inadvertently struck someone. I managed to accidentally bump it twice myself while doing cockpit checks!
The control sticks should never have interference with anything in the cockpit. This one should never have received an airworthiness certificate in this condition.
From the cockpit you can begin the final stages of the inspection, and that is the paperwork. Just as in the certified world, the airworthiness certificate should be visible, and the registration card should be on board and current, as well as the weight and balance. The word "Experimental" should be visible at the entry to the cockpit, and the operating limitations should be on board as well. Too many non-builders are unaware of the requirement for the operating limitations to be in the aircraft, and others claim they have never seen them or don't remember where they are. I point out to them that the airworthiness certificate is not valid without the operating limitations. Far too many new builders find them in their original paperwork folder instead of in the airplane. A new set can usually be acquired from the FAA in Oklahoma City if needed. Don't forget the passenger warning label required in view of the passengers.
Next are the logbook inspections. I want to see that Phase I was appropriately signed off (the proper wording is in the aircraft operating limitations), and I want to know who did the flight testing and what exactly was done. I inspected one aircraft that had been flying over seven years across three owners and never had Phase I been signed off! There have been times when I really question the thoroughness of the Phase I testing, especially including loading at different weights and CGs. Some builders have figured out that it is easier to copy VX and VY from other internet pilot operating handbooks, rather than take the time to correctly determine them for their specific aircraft.
While in the logbooks, other entries should include the required transponder and static checks, a check for completion of any applicable service bulletins or ADs, and any notated repairs from damage. Also, check for any major changes that perhaps should have required the aircraft to go back into Phase I. As an example, the requirement to notify the FSDO when changing from a fixed-pitch propeller to a constant-speed propeller is one that is often overlooked.
Once I've determined that the aircraft is in a safe, legal, and airworthy condition, it is time for a flight test. I like to watch the owner operate it as it gives me real insight as to the owner's confidence with the aircraft. I can also spend more time focusing on the engine and flight instrumentation to verify proper operation. Engines should run within normal operating temps as per the manufacturer of the engine, so it is a good idea to familiarize yourself with those specifications prior to the flight. Engines that reach maximum operating temps within a few thousand feet of the ground probably do not stand a good chance of reaching TBO. Flight controls and trim should be approximately neutral in cruise flight depending upon CG and loading, and there should be no required adverse control inputs required when flaps are deployed. One RV-10 that had flown for over 80 hours required so much right rudder pressure in cruise flight that my leg was actually cramping after 20 minutes. I eventually determined that the cap on the vertical stabilizer was offset 3/8 inch and was acting as a fixed trim tab. Removal and replacement with proper alignment fixed the problem.
Listen for changing engine/prop vibrations at various rpm, and verify accuracy of the aircraft tachometer with an optical tachometer from the cockpit. This is especially important on aircraft equipped with propellers that have restricted rpm ranges. Don't forget to check the radios for clarity and functionality. I like to turn the radio squelch off to check for any ignition noise. On well-equipped airplanes I will verify that an autopilot-coupled approach really does work as expected.
So there you have it. By following this guide to purchasing an Amateur-Built aircraft, you should feel confident that there shouldn't be any major surprises soon after you bring it home.