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All about Pre-Buy Inspections...

"Pre-Buy" is a common term often heard around aviation circles, yet a statement that has no real definition or meaning in reality. In addition, this term can be vastly understated and in many cases underrated.

For starters, there is no official FAA definition on the scope and detail utilized for a "Pre-buy or Pre-Purchase Inspection". That said, this is the single most important step in my opinion one should take and consider regarding any Aircraft purchase. If there is one step an Owner takes regarding the background of an individual’s qualifications this is likely the most important step in Aircraft Ownership. If an individual is going to be doing an evaluation of a potential Aircraft for you this is one item you don’t want to low budget or go into with blind trust. There is a new trend in service provider’s for this however that additional expense again gives one no guarantees or assurances. Just like vetting a new employee you really won’t know what you are getting until sometime down the road after being well vested. Discovering problems with an Aircraft after purchase is also much like this. These risks involved can be limited with a little bit of research typical to the time spent finding the "right Aircraft" for your mission needs.

Backing up a bit let’s compare a Pre-buy to an Annual. With an Annual Inspection there are basic guidelines that one needs to adhere to and at minimum, a complete check-list utilized during inspection process. This check-list is still no guarantee that the Aircraft hasn’t any hidden damage or internal failing components. I will go into further detail on how "Not all Annuals are the same" in yet another topic. So, essentially even an Annual Inspection may not reveal all the problems an Aircraft may have and still be considered "Airworthy" in the eyes of the FAA and documentation that supports this. You are however relying on the individual’s perspective, expertise and experience level performing this task to a large degree.

Specific knowledge of the particular Aircraft Model is paramount with an intimate knowledge of weak areas and expensive repairs including common wear items. This can be taken a step further with usage, environmental conditions and Aircraft history. Documentation is one area that needs to be considered during evaluation however this is a totally separate item in comparison the actual Aircraft integrity. It may look outstanding on the documentation however no relevance in regards to the actual Aircraft condition.

I want to expand on those three key areas mentioned. Usage, Environmental Conditions and Aircraft History. I see these as critical areas for initial consideration.


I often get inquiries about "High Time and Low Time" Aircraft. Starting with "High Time". I have seen FBI fleet replacement R182's & 210's that were in all respects excellent Aircraft. Some of these had 5-year Airframe Structural rebuilds by very competent facilities with a designed structures and quality program. When this heavy Maintenance is properly documented and implemented the end product integrity has not been compromised. With Governmental budgets that I have also been involved in they will allow funding for "Maintainability" however restrict new purchases. Military agencies are very familiar with this concept and they will rebuild the Aircraft due to funding at no expense spared often exceeding the new purchase cost in order to fall within the governmental established guidelines. So you get a very highly maintained Aircraft with more new parts than any other example of similar age on the market with high Airframe & component hours that by all practical standards is just as sound as a much newer model Airframe with low hours.

Now one critical item of concern here is the structural integrity and quality of the work that has been accomplished.

Let’s compare this to a Flight School Aircraft that has not been professionally flown and maintained by young aspiring A&P's or just Students trying to work off some of their payments in exchange for Flight time. These Aircraft are generally utilized for one purpose and that is training and by all practical reasoning "abuse". Service and Maintenance is generally maintained at minimal cost and only replacement items are as-needed. Plane club Aircraft in general are maintained in a similar manner as well as Pipe-line patrol and Survey Aircraft. Some of the later mentioned Aircraft may have much more hidden damage and considerations due to the heavy turbulence and low altitude operating environment.

Environmental conditions

I can’t speak on some of the extreme Cold climate conditions as there are specifics regarding this environment I am just not familiar with as I avoid such climates myself! That said I do see Aircraft and have evaluated Aircraft from literally all over the world and every Country and condition presents its own sets of issues to contend with. I am going to just address U.S based Aircraft and General Aviation to simplify.

Coastal region Aircraft in general may have corrosion issues. What some might consider a "Clean" Airframe from the Coastal areas in comparison to the same Aircraft located in Deer Valley Airport, Arizona. These can be two completely different scenarios? Now, this doesn’t mean you should concentrate your Aircraft search to Arizona only there are areas that need additional scrutiny during any pre-purchase on Aircraft with a high humidity level and in addition the corrosive Salt Air Environment. If an Aircraft is properly maintained with periodic corrosion treatments such as Corrosion-X or ACF, protected in a Hangar or not, frequent cleaning and sometimes even humidity controlled environments that can have little negative impact on an Airframe. Now compare this to an Aircraft that is sitting on a ramp 2 miles in off the Atlantic Ocean several years un-protected and you have serious corrosion and dissimilar metal issues. Many Aircraft are sold and relocated to various points of the country so the overall impact needs to be considered. I have had Aircraft come in where the Owner was completely unaware of the corrosion status shortly after having a major upgrade such as Avionics or new Interior. These types of investments in a heavily corroded Airframe would be better accomplished on a worthy Airframe as its useful life can quite often be very limited.

Since one of the areas I specialize in is Flight Control Rigging this literally brings in Aircraft from all points of the U.S. so I get to see a much broader group of Aircraft than the average local maintenance facility. I dislike very much being the individual that tells an Owner with this type of degraded Airframe that in my opinion I would not invest further funding in such an Aircraft. It is quite common that they want to bring the Aircraft in for Rigging as this is the last finishing touch after an extensive renovation. Sadly, they were completely unaware of the Airframe condition and years of environmental attack on the structure that should have otherwise rendered it an unlikely candidate for any upgrades.

Aircraft history

This is an area that not only includes the two groups previously mentioned but I would like to expand on the Structural impact as a result of accident history and repairs. Off Airport Landings, Ground-Loop's & Gear-Up incidents are the most common of these findings. Lightning Strikes and Severe Turbulence encounters as well are a completely different variable that should be considered. This type of encounter can cause significant damage that might easily remain undetected at first glance as this is generally un-documented.

Let’s discuss the obvious damage that is Structural repairs. This I can categorize as the good, bad and the ugly as I have seen it all. Some damage history is documented and other less than honest individuals want to disguise this or completely dishonest types just not document this entirely and unload the problem at a discount to the next unsuspecting individual that is after a bargain hunt. Getting back on track here, Damage History is just a common occurrence when looking for a used Aircraft. No damage history is preferred however when dealing with up to 50 year old Aircraft still flying today typical to an old Automobile, repair history is not necessarily a negative issue and if accomplished properly can be restored to the initial Aircraft configuration and as a bonus there may be a financial discount involved.

I just went through a repeated Gear Up repair history Aircraft that prompted me to write this article. The fact that there were two repairs wasn’t the biggest concern as was the level of workmanship utilized during the second repair. Unfortunately, this particular Aircraft was rejected during the pre-purchase due to the poor workmanship standards & practices utilized during repair. Had this been an Annual Inspection I would have given the Owner a list of discrepancies and not returned that Aircraft to Service since the repairs were that poor a quality. The Aircraft Owner was not at all aware of the actual condition and only relied on the individual that performed those repairs. The documentation thereof was in accord with all Aviation standards and practices. At least at face value this was accurate. The documentation of the repairs that were submitted had a fair account of the work performed however the key items such as Rivets and materials utilized vs what was installed and more importantly the overall workmanship itself never enters that particular equation.

It is quite common for the individual that completes and signs-off on the repair of the form 337 is the same individual. The repair work can be signed off on ones A&P rating and the completion of the work stating it is accordance with the repair procedure can be the same individual with an Inspection Authorization endorsement. I have submitted Major Repair and Alteration forms myself many times over the years in a typical manner. That said the Quality of such a repair is never scrutinized by any other individual other than the initiator. In this instance the Insurance adjuster was just as negligible as the individual performing the repair itself as they had no working knowledge of Engineering Standards and guidelines in performing such repairs let alone compliance with some of the associated repair process guidelines.

There were several items clearly visible to view from the exterior of the Aircraft that should have been obvious to someone with a working knowledge of these types of repairs. FAA Advisory Circular 43.13-1B is one guide to Acceptable Methods, Techniques, and Practices - Aircraft Inspection and Repair or the Cessna Structural Repair Manual would be a secondary source in this instance. These are two primary reference guidelines that were not followed and as a result several key elements were not adhered to in the repair process.

Now, let’s look at a proper repair in accordance with such standards accomplished at a high level of quality workmanship. Just as previously mentioned at the beginning of this article. A proper structural repair often is reflected as "damage history" at a reduced sale cost when in fact there it has no negative impact on the structural integrity of the Airframe at all.

There is one more area that needs to be considered in the "History" subject and that is "Maintenance History".

If one is looking at a 30-40 year old low time Airframe this is another area that requires specialized attention. Locating that "Barn-Find" may come with additional cost. Catching up on 40 years of neglect or non-existent maintenance comes with a cost. Over the years I have seen many a 20K-30K+ first time Annuals on Aircraft bringing up a poorly or minimally maintained Aircraft to the current maintenance standards.


Engine Condition is one of the second most critical areas. I find and many new owners facing a tremendous financial burden just shortly after a "pre-purchase" and "new Ownership".

There are primarily two Engine manufacturer designs out there for the Piston Aircraft World, Lycoming & Continental. There is no "one is a better product than the other" here as much as they both have slight variances and weak/strong areas. During a pre-purchase this is one area that may be quite controversial and there is a limit that many Sellers will allow any potential Owner or another Mechanic to do any evasive Inspection or intrusive disassembly on. Generally this is a case by case determination on just how extensive this evaluation can be. Preliminary checks by a competent Mechanic can help reduce the risk involved based on key elements during this evaluation.

It is standard practice to do a Compression Check however other than Compression Test, Borescope of Cylinders and a basic overall visual Inspection the Engine may still have many issues not detected by these basic means that can in instances be very marginal and destructive to the point of short term failure. This is where you need to consider risk and reward vs cost and allowances.

One example may be a fairly low time Engine with very low activity. These Engines may have hidden damage and corrosion. Not very apparent at initial purchase however once the Engine is put back in service can start to develop problems that will get progressively worse to the point of premature failure and eventual removal & replacement.

On the other hand it may be a very High Time Engine with minimal useful life remaining and a full discounted cost already taken into consideration with Sale cost. * I prefer this scenario as I will know the condition after rebuild.

Again, dependent upon Environmental Conditions and Usage just like the Airframe these issues may have a negative impact or not. This is where having expertise on the various issues and experience levels of the individuals performance is key to helping you make an informed decision prior to purchase. Familiarity with the various Engine Manufacturers strong & weak areas particular to model is paramount when doing this evaluation. There are some limited areas of Inspection and signs of potential deficiencies that only experience will detect. The level of intrusive inspection allowed by the Seller will also limit how far one can be allowed to complete this portion of evaluation. Many variables such as level of Inspection, preliminary conditions and findings will determine the outcome of your decision to request further evaluation or financial consideration and discounts for pending potential deficiencies.


I have had many prospective buyers state “The Avionics are old and need replaced however I plan to do this over time after purchase".

My advice regarding obsolete Avionics is generally old and dated Avionics especially on an old Aircraft not being utilized is more likely to fail immediately after placed back in service. Therefore your time limitation for taking action has just been decreased to the point of being grounded without any resources left for repairs. Try not to be put in this situation if at all possible. Today’s cost of Avionics can easily be 50% of the Aircraft value. Installing any new Avionics and resale value generally results in an immediate loss. Doing a complete Avionics upgrade and resale is much like a new Automobile purchase and driving it off the lot to re-sell. Probably a larger loss can be expected unless you own the Avionics Shop.

So Avionics should be considered at initial purchase and should for all practical measures meet your profile needs. Better to purchase an Aircraft with the equipment that meets your current & future mission needs and let the previous Owner take the negative impact on upgrade cost vs resale value.

This brings me back to my original statement that not all Pre-Purchase Inspections are the same and you should do your due diligence in finding the right individuals to accomplish this task dependent upon your risk level and budget. If you have a very minimal budget to start with then the pre-purchase may not be an area you can afford to cut cost on in the first place.

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