There is no such thing as a "standard deduction."

If you own an aircraft of any age, especially if it has retractable gear, then it likely has some form of damage history. But how does that damage affect the overall value and what questions should you, as a buyer or seller, ask about that damage?

First, not all damage is created equal. An aileron that was damaged during a towing operation and then replaced with a new unit does not affect value the same way as wing damage caused by a fuel truck backing into the aircraft.

Why?

Because parts that are completely replaceable usually have no bearing on the structural integrity of the aircraft. The replaced parts have no damage, therefore the stigma associated with damage should not apply to that component or aircraft. This goes for flaps, rudders, elevators, gear doors, and even some pieces of aircraft skin. This applies only if the damage was isolated to that component and did not involve other structures.

Damaged structural components (ribs, stringers, spars, etc.) are a different story. Many times, these items must be repaired, not replaced. No matter how well they were repaired, they are not in as good a condition as an undamaged part (at least in the eyes of potential buyers). Whether this damage and repair occurred last week or 20 years ago has considerable bearing on any devaluation. Since old repairs have stood the test of time, and the aircraft has been largely depreciated anyway, the deduction amount is usually a lower percentage than for an identical and recent damage event.

The four most important questions to be asked about a damage event are:

• What was the extent of the damage? Was it just superficial or did it involve major structural components?
• How was the repair made? Did the mechanic thoroughly document the repair and used new, approved parts?
• When did this damage occur? Has the repair been able to withstand the stress of time?
• Is evidence of the repair visible? Are there any wrinkles in the skin? Are rivet lines around the damage consistent with surrounding rivets?

Regardless of whether you're buying or selling you should avoid summarily applying a 10 or 15% discount to the value just because the aircraft has previous damage. Major damage that occurred decades ago may only warrant a small decrease while recent moderate damage may sufficiently stigmatize that aircraft as to warrant a substantial deduction.

While it's true that you'll only know what effect damage has on the price when you get ready to make, or accept an offer, a trained appraiser may help you understand the true nature of the damage incident and how it really affects value.