What is the most expensive part of your plane? Logbooks!

Three of the major factors that affect value are airframe time, engine time and damage history. Without a set of COMPLETE and ORIGINAL logs, it's no longer possible to prove any of the above. The only way to positively confirm airframe time is to start on page 1 of the first log, and check the math at each and every annual. Read all the entries carefully, looking for a replacement tach or hour meter. If you have an aircraft with less than average TTAF, and you lose even one of the airframe logs, any value premium your aircraft was entitled to just went away. There's just no way to prove it.

DO NOT rely on mechanics math - usually they will just take the previous figures as gospel when entering the annual times- you'd be surprised how often an error is carried forward for many years!

The disappearing engine log can be a bit more complex. If you have the airframe logs showing it's installation at the last major (along with other records indicating that it WAS a major overhaul), you're in pretty good shape, and any doubt about the engine's time since major overhaul will go away at the next major. If you have neither airframe nor engine log, a prudent buyer has to assume that the engine is past TBO, and value it accordingly.

Any time an aircraft is repaired after a damage incident, the repairs will be entered in the airframe log along with a 337 ("Major Alteration or Repair") form. While a copy of every 337 is supposed to be filed with the FAA, it does not always happen, and even a 337 search with the FAA cannot be relied upon to be complete. Since the owner is actually not required to keep the 337 after one year, the only damage evidence left will be in the airframe log. If it goes away, so does any "No Damage History" value- the prudent buyer must then assume that the aircraft HAS a major damage history, and that this damage and repairs occurred just prior to the beginning of the earliest available log. In spite of sellers' desperate claims, reconstructed logs do NOT constitute "Complete and Original" records, and do not hold the same validity.

Here's a few tips for current (and future) owners to protect your investment:

ALWAYS carry a photocopy of the last annual inspection results and signoff, as well as the AD note list. (mostly for the purpose of those pesky ramp checks).

NEVER leave your logs with your mechanic to be "signed off later". In fact, you should let them work with the copies, and bring in the originals only when the work is finished and they're ready to be signed. Then take them away- FAR away!

LOGS CAN ACCOUNT FOR UP TO 50% OF YOUR AIRCRAFT'S VALUE!
NEVER carry the originals in the aircraft,
NEVER leave the originals in the hangar, and
NEVER carry them around in your car!

Sadly, we have seen logs lost under every one of these circumstances. The prudent owner keeps the logs in the same place as he/she keeps other important papers (we recommend a safe deposit box), and exposes them to potential loss only when absolutely necessary.

For some intruguing stories about missing and/or reconstructed logs, read the Plights of Planes horror stories on our web site.