A pre-purchase inspection is not an annual inspection, although the buyer and seller could agree to such an arrangement. The object is to examine the aircraft for damage and wear that might not be evident to an untrained eye and to form an educated guess as to maintenance problems that might arise in the future.
Obviously, the outcome of a pre-purchase inspection is likely to affect price. If a mechanic discovers a serious problem, the buyer is not likely to close the deal without a reduction in price equal to the cost of the repair. For that reason, the seller may be wary of such an inspection. Nevertheless, it is to the buyer's advantage to insist upon one. The aircraft may be found to be unairworthy because of faulty equipment or lack of compliance with an airworthiness directive. Once the deal is closed and the buyer takes possession of the aircraft, it will be extremely difficult to force the previous owner to bear the cost of repairs that should have been performed before the sale.
The extent of a prepurchase inspection depends upon the complexity of the aircraft and the wishes of the buyer. Because of the complexity of its systems, a late-model, turbocharged Cessna 210 requires a more thorough check-out than a simple Ercoupe. A wood-wing aircraft should be inspected for rotting or drying of the wooden components. Fabric-covered aircraft should be subjected to punch tests.
The buyer should specify the shop conducting the inspection or annual, but it is often the seller who rules in this decision. If that is the case, the buyer is well advised to evaluate the shop's credibility and reputation. The inspection could amount to a "paperwork annual" in which the mechanic does his work looking through an office window, fingers attached to a coffee cup.
Poor annual inspections technically may not be fraudulent, but there have been incidents of improper repairs using stove bolts, hardware-store pop rivets, and other atrocities that cost a new owner with a fresh annual more than $5,000 to rectify. There is legal recourse in such cases, and the Federal Aviation Administration probably will be interested in a visit with the inspector, but the aircraft owner still loses money and use of the aircraft.
Following is a link to a printable checklist of items that should be covered on a thorough pre-purchase inspection. Many of the checks can be performed by the buyer, but a properly qualified authorized inspector (AI) or airframe and powerplant mechanic (A&P) should be retained to examine critical items such as the engine and logbooks.
The following is a link to a printable checklist that has been designed to assist you and your mechanic in evaluating the condition of an aircraft. A pre-purchase inspection can be as simple as a glance or as complex (and expensive) as an annual inspection. With this in mind, ALWAYS discuss your intentions and what you expect from the mechanic first. An unsatisfactory condition is not necessarily cause for rejection of the aircraft, but it should be treated as a point for further investigation and/or negotiation with the seller. The money spent on a pre-purchase inspection can be well worth the price when compared to the size of your investment and the potential for loss.