Horrible things could be missing from your plane's log book.. and still be perfectly legal. FAR 14 91.417

You're buying a plane, you and your broker carefully study the logs and are very happy with the spectacular history the plane has. What a deal!

But what if...a bunch of nasty stuff has been removed from the logs. And it's done completely legally? FAR 14 91.417 Maintenance Records clearly lists what record keeping is required. The question we will answer here is what's not needed. Let's start with looking at minimal set of what's needed:

• Must keep "permanent records" forever on engine, air frame and props:
• Total time in service
• Time since overhaul
• Time since last inspection
• AD directives

Here';s an example of an engine log that is very minimal but completely legal:

• 1150 total time in service
• 1150 since last overhaul
• 150 hours since last inspection
• ADs list that has been complied with
• Manufactured in 2001

These can be written on a napkin, you don't need a logbook. Notice there are no entries from a mechanic, these are only necessary for last 12 months in operation. If the plane has been sitting for 366 days all records can be destroyed. As for the times above? They need to be written down.. somewhere. On a napkin is technically legal.

Expiring Records

Everything else is an "expiring record", to be kept for 12 months after work is done, or, if same work is repeated, superseded by previous.

If a seller wants to increase the price of a plane with a spotty history, they can make a whole new log book. There are no regulations about "selective" record keeping.

Hard landing inspection? Remove it.

Prop strike? Remove it.

Collapsed landing gear? Remove it.

Upgraded to a new starter? Keep it.

Oil changes? Keep them all.

Next big question: Why do you care?

1. If the FAA asks you to provide them with maintenance records, you don't need to give them full log books, just the minimums listed above. 12 months of records, running times, and inspection status.
2. If you're a buyer, assume that someone has altered record and removed bad stuff.
3. If you're a seller you could increase value by making records seem nicer than they really are.
4. If you're an owner and you think you know your plane's history, think again.

Looking at this from FAA perspective it makes sense. The plane must be kept in airworthy condition to fly, and life limited parts and inspections must documented. What happened 5 years ago to the plane? They don't care. Even if there was some incidents, the plane was brought to airworthy level again if it's flying today, so the details of history are not important to the FAA.

I think the the big misunderstanding for owners is that we incorrectly assume log books are an absolute source of truth designed to provide information to future owners. Really, they're for FAA and airworthiness status. Not for valuation purposes.