Aircraft Maintenance Records: What FAR 91.417 Requires You to Keep

Ask an experienced owner what they’d grab first if they had to evacuate the hangar, and a surprising number say “the logbooks.” There’s a good reason. A well-maintained airplane with missing records can be nearly unsellable, and a gap in the paperwork can ground an otherwise perfect aircraft until the history is reconstructed. The records aren’t bureaucratic overhead bolted onto maintenance — under Part 91, they are a core part of keeping the aircraft legal to fly.

The rule that governs them is 14 CFR 91.417, “Maintenance records.” It’s short, it’s readable, and almost every GA owner-operator misunderstands one important thing about it: not all maintenance records are kept for the same length of time. Get that distinction right and the whole system gets simpler.

The rule, in plain language

Section 91.417 puts the responsibility for keeping records squarely on the owner or operator — not the mechanic, not the shop. Your A&P makes the entries and signs the work off, but you are the one required to keep, organize, and produce those records. If a logbook walks out the door with a shop that closes, that’s your problem to solve, not theirs.

The regulation then sorts everything you must keep into two groups, and assigns each group a different retention period. This is the part worth internalizing, because the two groups behave completely differently.

The core idea: 91.417 splits records into “work records” (every individual maintenance entry) and “status records” (the running picture of the aircraft’s total time, inspections, ADs, and life-limited parts). Work records can eventually be retired. Status records follow the aircraft for life and transfer to the next owner. Mixing these two up is the most common recordkeeping mistake in GA.

Bucket one: the record of each job

The first group, under 91.417(a)(1), is the record of maintenance, preventive maintenance, and alterations, plus the records of required or approved inspections — the 100-hour, annual, progressive, and so on. Every time work is done on the airframe, an engine, a propeller, a rotor, or an appliance, an entry gets made. Each of those entries is required to include three things:

A description of the work performed (or a reference to data acceptable to the Administrator); the date the work was completed; and the signature and certificate number of the person approving the aircraft for return to service. That last element is what turns a description of work into a legal approval — and it’s why only appropriately certificated people can make it. As an owner you can perform and log certain preventive maintenance yourself under Part 43, but the signoff still has to meet the rule’s requirements.

How long you keep the job records

Here’s the part that surprises people. These individual work entries under (a)(1) have to be retained until the work is repeated, until it’s superseded by other work, or for one year after the work was performed — whichever applies. In other words, the entry for a specific oil change doesn’t have to live forever; once that oil change has been done again, the rule’s minimum retention for the old entry has been met.

In practice almost nobody throws old entries away, and you generally shouldn’t — a deep maintenance history adds resale value and helps your mechanic spot patterns. But it’s useful to understand that the legal minimum for these records is limited. The records that truly must never be lost are in the second bucket.

Bucket two: the records that follow the airplane forever

The second group, under 91.417(a)(2), is the running status of the aircraft. These are the records that must be retained and transferred with the aircraft when it’s sold. They include:

The total time in service of the airframe, each engine, each propeller, and each rotor. The current status of life-limited parts of each airframe, engine, propeller, rotor, and appliance. The time since last overhaul of every item installed that’s required to be overhauled on a specified time basis. The current inspection status, including the time since the last required inspection. The current status of applicable Airworthiness Directives. And copies of the FAA Form 337 for each major alteration to the airframe and currently installed engines, propellers, rotors, and appliances.

On the AD record specifically: 91.417 requires that for each applicable AD you record the method of compliance, the AD number, and the revision date — and if the AD is recurring, the time and date when the next action is required. A note that just says “AD complied with” doesn’t meet the standard. This is exactly why a clean, current AD list is one of the first things a buyer’s mechanic asks for.

A note on “total time in service”

“Time in service” has a specific regulatory meaning that’s worth pinning down, because it’s not the same as tach time or Hobbs time. For maintenance records, time in service runs from the moment the aircraft leaves the surface of the earth until it touches down at the next point of landing — in other words, wheels-up to wheels-down. Tach time is an RPM-weighted engine reading, and Hobbs is typically clock time with the engine running. Many owners record and track all three, but when the regulation refers to total time in service, this airborne definition is the one it means. (We dug into the tach-versus-Hobbs confusion in a separate article — worth a read if those two ever blur together for you.)

When you sell: 91.419

The companion rule, 14 CFR 91.419, closes the loop. When you sell or otherwise transfer the aircraft, you’re required to transfer the bucket-two (a)(2) records — the total times, life-limited part status, time since overhaul, inspection status, and AD status — to the new owner. The buyer’s airplane is only as legal as the history that comes with it, which is why missing or disorganized status records can sink a sale or knock thousands off the price.

Why this matters at sale time. Two owners list nearly identical airplanes. Owner A hands the buyer’s mechanic a clean, current snapshot: total times, a complete AD list with method of compliance and next-due dates, life-limited part status, and the 337s for every major alteration. The pre-buy moves quickly and the deal closes.

Owner B has all the maintenance in the world but no organized status records — the AD compliance is scattered across years of entries and nobody can produce a current list. The buyer’s mechanic has to reconstruct it by hand, the pre-buy drags on, and the buyer either walks or negotiates hard. Same airplane condition; very different outcome, decided entirely by the records.

The mistakes that bite owners

Most recordkeeping problems aren’t exotic. They come from a handful of recurring habits:

Habits that create gaps:

• Treating the shop as the keeper of your records
• Letting AD status live only inside scattered work entries
• No running total-time figure you actually trust
• Recording “AD complied with” without number, revision, or next-due
• Discovering a missing logbook only during a pre-buy

Habits that build a clean history:

• You own and back up the records; the shop just makes entries
• A standalone, current AD status list maintained over time
• Total time, time-since-overhaul, and inspection status kept up to date
• Each AD logged with method, number, revision date, and next-due
• Status records organized and ready to transfer at any time

It comes down to a simple structure: 91.417 defines two record groups, each with its own retention rule. An individual work entry has a minimum retention of one year — or until that work is repeated or superseded — while the status records follow the aircraft for life and transfer at sale.

How to keep it audit-ready without the dread

You don’t need a complicated system — you need a reliable one. The goal is simple: be able to answer, on any given day, “what’s my total time, what’s my inspection status, and what’s the current state of every AD on this aircraft?” If producing that snapshot would take you an afternoon of digging, that’s the gap to close.

The reason the two-bucket structure maps so naturally onto software is that the bucket-two records — total times, inspection status, AD status, life-limited parts — are exactly the things a tracker can keep current as a running picture rather than something you reconstruct after the fact. That’s the idea behind TachMinder: every logged event updates the status records automatically, AD compliance is tracked as its own list with method, number, and next-due rather than buried in narrative entries, and the whole snapshot is ready to hand to a mechanic or a buyer whenever you need it. The point isn’t to replace your logbooks or your A&P’s signoff — those are the legal record. It’s to make sure the picture they add up to is always current and always at your fingertips.

However you do it — a tracker, a binder, or a spreadsheet your mechanic helps you keep — learn the shape of 91.417 once and the rest follows: know which records are the permanent status records, keep those bulletproof, log every job with a proper signoff, and never let “I’ll organize it before the annual” turn into a missing-paperwork surprise.