The Savvy Aviator #23: Maintenance Records

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Maintenance records are a pivotal element of your aircraft's maintainability and resale value. Are yours in good shape? AVweb's Mike Busch says the FAA's regulations may not be thorough enough when the time comes to sell the plane.

The Savvy Aviator

No aircraft is considered airworthy by the FAA until the weight of its paperwork exceeds its maximum certificated takeoff weight (or so goes the old joke). We in aviation are always complaining about the amount of paperwork that the FAA, in its infinite wisdom, makes us do. Any aircraft owner who has gone through the process of getting an IFR-approach-certified GPS installation approved knows that it sometimes it seems excessive and burdensome.

But the maintenance records for our aircraft -- what most of us call aircraft and engine logbooks -- are different. They're a fundamentally important responsibility of aircraft ownership. They're vital to our ability to maintain our aircraft properly. They also play a crucial role when we want to sell our aircraft or buy another -- if you doubt this, just try selling an aircraft whose logbooks have been lost.

The FAA requires us to keep maintenance records for our aircraft. In fact, there are more than a dozen separate FARs that define what records must be kept, for how long, and by whom.

These regs define the minimum records that we as aircraft owners must keep. But they also leave quite a bit to the judgment of the folks doing the recordkeeping (the aircraft owner and his mechanic). As conscientious aircraft owners, I believe we can and should be doing more than the bare-bones minimum required by the FARs. In this article, I'll start by discussing what the FAA says our maintenance records must contain, and then offer some personal observations about what I think they should contain.

Whose Responsibility?

Most aircraft owners assume that maintenance records are the responsibility of their A&P or maintenance shop. In fact, many owners leave their maintenance records "on file" at the shop and never look at them. The FARs, however, are very clear in placing primary responsibility for both maintenance and recordkeeping squarely on the shoulders of the aircraft owner, not the mechanic or shop. If you're not entirely clear on this concept, you should haul out your FAR book (or click here) and brush up on the following regs:

  • 91.405 -- Maintenance required.

  • 91.407 -- Operation after maintenance.

  • 91.409 -- Inspections.

  • 91.411 -- Biennial altimeter/Mode C certs.

  • 91.413 -- Biennial transponder certs.

  • 91.417 -- Maintenance records.

  • 91.419 -- Transfer of maintenance records.

  • 91.421 -- Rebuilt engine maintenance records.

Owners who never look at their maintenance logs may not be in compliance with the FARs. For instance, FAR 91.405 says:

"Each owner or operator of an aircraft ... (b) shall ensure that maintenance personnel make appropriate entries in the aircraft maintenance records indicating that the aircraft has been approved for return to service."

and FAR 91.407 says:

"(a) No person may operate any aircraft that has undergone maintenance ... unless ... (2) the maintenance record entry required by 43.9 or 43.11, as applicable, of this chapter has been made."

How ya gonna do that without looking at the logbooks? In my seminars I strongly recommend that owners always keep their aircraft maintenance records in their personal possession (preferably in a fireproof lockbox), and never keep them on file at their maintenance shop (as so many owners do). Another huge no-no is carrying the maintenance records in the aircraft -- don't ever do that.

Some of these regs contain hidden "gotchas" that every owner should know about. For example, FAR 91.407 requires that the initial flight after any installation that "may have appreciably changed its flight characteristics or substantially affected its operation in flight" must be a "maintenance test flight" during which no non-crewmember passengers may be carried, and must be logged as such. In particular, any installation that requires a Form 337 and an approved Airplane Flight Manual Supplement (such as a horsepower increase, STOL kit, vortex generators, or even an approach-certified GPS) probably meets the requirements of this reg.

When I had an approach-certified GPS installed in my T310R, the avionics technician who did the installation came along with me on the test flight. Was that legal? Hmmm.

While the FARs place sole responsibility for maintenance recordkeeping on the aircraft owner, they simultaneously place responsibility for recording and signing off maintenance work on whomever actually does the work -- generally (but not always) an A&P mechanic. Those regulations appear in FAR Part 43, a portion of the regs you may not have studied unless you're a mechanic. But since you, as an aircraft owner, are held responsible for the adequacy of your aircraft's maintenance records, this is really stuff you should know. The pertinent Part 43 regs include:

  • 43.2 -- Overhauled vs. rebuilt.

  • 43.3 -- Persons authorized to do maintenance.

  • 43.5 -- Return to service after maintenance.

  • 43.7 -- Persons authorized to return to service.

  • 43.9 -- Maintenance records (general).

  • 43.11 -- Maintenance records (inspections).

  • 43.12 -- Falsification of maintenance records.

Specifically, FAR 43.3 is what gives you -- as an aircraft owner who holds a pilot's certificate but not an A&P license -- the authority to do preventive maintenance on your aircraft without any requirement for an A&P to be looking over your shoulder or signing off your work. FAR 43.9 says that when you do such preventive maintenance, you are required to log it and sign it off. FAR 43 Appendix A(c) defines precisely what kinds of maintenance is defined as "preventive maintenance" and therefore legal for a non-A&P owner/pilot to perform without supervision.

In short, if you're an owner who sometimes swings wrenches on your airplane, you need to bone up on Part 43.

What Must Be Logged?

For the majority of us who operate under FAR Part 91, the basic requirement to keep maintenance records comes from FAR 91.417. This reg specifies both what information must be recorded and how long those records must be preserved.

Specifically, you (as the aircraft owner) are required to keep records of any maintenance, preventive maintenance and alterations -- plus records of 100-hour, annual, progressive and other required or approved inspections -- for the airframe and each engine, propeller and appliance of the aircraft.

What the heck is an "appliance?" I didn't know either, so I looked it up in FAR 1.1:

"'Appliance' means any instrument, mechanism, equipment, part, apparatus, appurtenance, or accessory, including communications equipment, that is used or intended to be used in operating or controlling an aircraft in flight, is installed in or attached to the aircraft, and is not part of an airframe, engine, or propeller."

Basically "appliance" is a catch-all phrase the FAA uses for aircraft parts that aren't airframe parts, engine parts, or propeller parts. For example, instruments and avionics are considered "appliances." All maintenance on such appliances must be logged.

For all such maintenance and inspections, FAR 91.417 requires that the following items be recorded:

  • A description of the work performed, or a "reference to data acceptable to the Administrator." (Examples of the latter would be, "Adjusted voltage regulators in accordance with Cessna 310 Service Manual," or, "Tested KT-76A transponder in accordance with FAR 91.413.")

  • The date the work was completed.

  • The signature and certificate number of the person approving the aircraft for return to service. (In the case of preventive maintenance performed by a non-A&P owner, this would be the owner's signature and his pilot certificate number.)

In addition, FAR 91.417 requires the following additional information to be maintained in the aircraft maintenance records:

  • Total time in service of the airframe plus each engine and propeller.

  • Current status of any life-limited parts. (Older aircraft certificated under CAR 3 generally do not have life-limited parts unless they're pressurized. Newer aircraft certificated under FAR 23 often have life-limited parts; for example, the whole airframe of the Cirrus SR20 and SR22 is life-limited.)

  • Time since last overhaul of all items required to be overhauled at a specified TBO.

  • Current inspection status of the aircraft, including the time since the last required inspection.

  • Current status of applicable Airworthiness Directives, including method of compliance and, for recurring ADs, the time and date when the next action is required.

  • Copies of all Form 337s required for major alterations (including any items approved via STC, even innocuous ones such as aftermarket strobe lights and sun visors).

Kept For How Long?

FAR 91.417 goes on to define how long such maintenance records must be retained by the aircraft owner:

  • Records of maintenance work and inspections performed must be kept until the work is repeated or superseded by other work, or for one year after the work is performed.

  • Records of total times-in-service, times since overhaul, current inspection status, current AD compliance and 337 forms must be retained permanently and transferred with the aircraft when it is sold.

  • If the aircraft flunks an annual or 100-hour inspection and the inspector furnishes the owner a list of defects, that list must be kept until the defects are repaired and the aircraft is approved for return to service.

Now I find this rather interesting. The FAA is saying that whenever I change my engine oil and oil filter, I can legally throw away any records of prior oil and filter changes. Or when the aircraft goes through annual inspection, all records of previous annual inspections may be discarded. It also says that if I replace three cylinders at mid-TBO, records of that fact may be destroyed a year later. Does any of this make sense?

I suppose it does from the FAA's regulatory perspective. As far as the FAA is concerned, an aircraft is either airworthy or unairworthy. If the aircraft has just gone through an annual inspection and been signed off by an IA, that's all the FAA needs to know. It doesn't matter to the Friendlies whether the aircraft spent the preceding five years hauling cancelled checks every night, or if it was inactive and out of annual for those five years, rotting away in some hay field.

But suppose you bring your plane to the shop for maintenance:

"Boy, that left main tire looks pretty worn," says the mechanic. "How long has it been since you replaced it?"

"Beats me," you reply. "All I know is that it has been more than a year. All maintenance records older than that have been destroyed by authority of FAR 91.417(b)(1)."

Or suppose you were a prospective purchaser. You ask to inspect the aircraft logbooks and find that only the most recent annual is logged, and that all record of maintenance work going back more than a year has been destroyed by the aircraft owner. How would you feel about buying that aircraft?

I don't know about you, but when I'm shopping for an aircraft, I want to see detailed maintenance records going all the way back to when the aircraft first rolled out of the factory. Although not required by the regs, such records can provide an excellent "feel" for how the aircraft was taken care of by its previous owners. Conversely, maintenance records that are missing or sketchy tend to raise all sorts of red flags in the mind of a prospective purchaser.

Beyond the FARs

I think it's vitally important for every aircraft owner to take control and responsibility for his or her aircraft's maintenance records. I make a point of keeping unusually detailed and complete maintenance records ... the kind I'd like to see if I were buying an aircraft. While I don't log every cotter pin and tie-wrap, I do try to err on the side of completeness in my recordkeeping.

Let me show you what I mean. Here is the airframe logbook entry for my 1992 annual inspection, made by my IA before I took control of my maintenance records. It's pretty typical of what I see in most aircraft logbooks I look at:

BEFORE: Logbook entry for my 1992 annual

These days, I do virtually all my own maintenance work and sign it off myself as A&P/IA. But long before I became an A&P, I decided to start preparing all the maintenance logbook entries myself for sign-off by the A&P or IA approving the work. Here's the entry I prepared for my 1994 annual inspection:

AFTER: Logbook entry for my 1994 annual.
As you can probably tell, I prepared the entry on a self-adhesive sticker using word processing software and an inkjet printer. This lets me fit a lot more detail into a reasonable amount of logbook space, and also gives my IA a chance to review the wording and request any changes before the entry gets pasted into the logbook. It's a technique that seems to work well both for me and for the mechanics with whom I've worked.

You may notice that one habit I've developed is to include part numbers whenever I log work that involves parts replacement: lamps, filters, spark plugs, ELT batteries, etc. This has proven to be a great time-saver because next time I need to replace the same part, I can quickly find the part number in my logbook rather than having to search through a huge aircraft parts manual and then go through a "when exhausted use" wild goose chase when it turns out the original part number has been superseded two or three times!

The adlog System

When I first bought my T310R in 1987, its maintenance records were still being kept in the little airframe and engine logbooks that Cessna provided when the aircraft was new:

Original maintenance records for my Cessna T310R.

I continued to use those same logbooks for several years, until an IA suggested that I consider changing over to a system called "adlog" offered by AeroTech Publishing of Southhold, Long Island, N.Y. I took one look at the adlog system, fell in love with it, and have been using it ever since.

The adlog system consists of a three-ring binder with ten color-coded index tabs:

The adlog binder.

The first four sections contain maintenance logbooks for the airframe, engines, propellers and avionics. For my twin, there are two engine logbooks and two propeller logbooks, making six books in all:

Some adlog logbooks.

The cover of each logbook is color-coded to match the corresponding index tab, so it's hard to refile a log in the wrong section of the binder. Each of these logbooks is a full 8 by11 inches, so they provide lots of room for the sort of long-winded maintenance entries I prefer, plus room to staple in yellow tags and other pertinent forms and documents:

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Typical page from one of my adlog engine logbooks.
(Click for larger version.)

The fifth section of the adlog binder is earmarked for filing any applicable service bulletins that you may want to keep on file. Just three-hole-punch them and stash them in the binder. I keep the TCM service bulletins for torque values and fuel-injection adjustments here, for example, plus a "cheat sheet" on Cessna 310 landing-gear rigging adjustments.

Keeping Track of ADs

The next two sections of the adlog binder are used to keep track of Airworthiness Directives, and account for how the system got its name. The AD tracking system starts with a computerized print-out of all ADs that apply to your particular make and model of aircraft; AeroTech Publications prepares one for you when you first subscribe to the adlog service, and then sends you an updated listing every year:

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An adlog listing of applicable ADs.
(Click for larger version.)

It then contains a separate page for every applicable AD, each containing the text of the AD and a place to log compliance. ADs that have been permanently complied with are filed in the sixth binder section (green tab), while ADs requiring further or recurring action are filed in the seventh section (red tab):

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Typical adNote page. The red heading denotes that this is a recurring AD.
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Once again, AeroTech sends you a complete set of applicable AD sheets when you sign up for adlog, and then mails you additional sheets throughout the year as new ADs come out or old ones get revised. The cost of this annual update service is astonishingly reasonable -- presently $18/year for singles and $21/year for twins.

Whenever you receive a new or revised AD in the mail, you check the fine print to determine whether the AD is actually applicable to your particular aircraft. (Do you have the affected component installed? Does your a/c serial number fall within the applicability range of the AD? Etc.)

If the AD doesn't apply to your aircraft (which is the case more times than not), you simply mark the sheet with the reason it's inapplicable (e.g., "N/A by serial number") and file it at the end of the green-tab section (ADs permanently complied with). If the AD does apply -- or if you're not sure whether or not it does -- you file it at the end of the red-tab section (ADs requiring further action) and plan a chat with your mechanic.

At annual time, of course, your IA has everything needed in one place, and the usual "AD search" becomes a trivial exercise.

Other Records

The eighth section of the Adlog binder is used for filing copies of all applicable Form 337s as required by FAR 91.417. These forms are required for any major alteration or repair, including any installation that requires an STC. For example, I have 337s here for my Brackett air filters, Whelan strobes, Boundary Layer Research VGs, Rosen sun visors, and both of my IFR approach-certified GPS navigators.

The ninth section of the binder provides a place for filing weight-and-balance records. Although it's not required, I keep a complete historical record of every W&B change since the aircraft was new in this section.

The final section of the binder is for miscellaneous maintenance records. I keep my oil analysis records here, for example. I also have a three-hole-punched clear plastic envelope in which I keep the old pre-adlog logbooks that I inherited when I bought the airplane, so I have the total maintenance history of the airplane in one place.

I heartily recommend the adlog system to all aircraft owners. It's a terrific, well-thought-out system that quickly pays for itself by saving your IA valuable time at annual, and (if properly kept up) can add immensely to the resale value of your aircraft as well. If you prefer not to use adlog, you can at least adopt some of its ideas -- such as the three-ring binder format and the 10-section structure -- in organizing your own maintenance records. You'll find it time well spent.

See you next month.


Want to read more from Mike Busch? Check out the rest of his Savvy Aviator columns.