Airframe and Powerplant

ADs for the Owner

December 1, 2001

Perseverance and a bulldog-like attitude are required to keep up with airworthiness directives

When John Q. Public bought a 1981 Cessna 172RG last summer he made the leap from airplane renter to airplane owner. At the airplane's first annual, his mechanic called and told Public that there was a new airworthiness directive (AD) requiring a detailed inspection of the landing-gear pivot assemblies. How bad can that be? wondered Public.

The pivot assemblies are expensive, forged aluminum parts that transmit motion from the hydraulic actuators to the landing-gear legs by pivoting through approximately 180 degrees of motion. Because they support the main landing-gear legs, these pivots bear the brunt of hard landings. AD 2001-06-06 requires the removal of the left and right pivots for inspection and replacement of the pivots if cracks are discovered. If both pivots are cracked, the estimated cost to replace them is more than $7,000, or approximately 10 percent of the value of Mr. Public's new airplane.

Public has instantly learned about one of the differences between renting and owning. Like it or not, ADs are part of aircraft ownership. Owners can and should oversee AD note compliance and, if necessary, develop a comprehensive AD compliance record for their airplanes.


An airplane is not airworthy unless every applicable AD has been complied with in the appropriate manner. While most owners leave this task to a mechanic, some homework on the owner's part will pay off.

When a mechanic is forced to spend time creating an AD compliance record, the owner pays for it. "I had a [Cessna] Cardinal customer who came in here with his records in a box," said Jim Musgrove, director of maintenance at Boeing Field's Wings Aloft in Seattle. "I can easily spend four to five hours getting it straightened out."

Motivated owners who are willing to spend a few evenings overhauling and organizing their AD records will reduce costs and face fewer surprises related to future maintenance requirements.

Each time an annual is signed off, the authorized inspector (AI) is affirming that the airplane is airworthy. Plane Sense, a general aviation information publication (FAA-H-8083-19), defines airworthy as being in compliance with the type design (type certificate) and being safe to fly. AD notes are additions to the type design. The regulations place the responsibility for an airplane's airworthiness squarely on the shoulders of the owner (or operator). Actually, creating a list like this is pretty easy, but it does require perseverance and a bulldog-like attitude. Here's an example: There is an AD note that applies to more than 30,000 altimeters (marketed by United Instruments) that were installed in general aviation airplanes in the 1970s. To determine whether an altimeter is affected, the model, part number, and serial number must be researched. This means the altimeter must be removed from the panel or some very interesting under-panel convolutions with a flashlight and mirror must be performed.

The big ADs that are applicable to the engine, airframe, and propeller are rarely missed, but airworthiness is often compromised by the lesser-known ADs listed in the appliance section. The appliance section is the catchall listing — three AD notes against various types of circuit breakers, two against magneto switches, and a couple against commonly used fire extinguishers are examples of appliance ADs.

New AD notes are issued every two weeks and are numbered according to the date and order of issuance. The first set of digits indicates the year of issuance; the second group indicates the week of issuance; and the third group of digits indicates the sequential position in the weekly grouping. The United altimeter AD mentioned above is listed as 74-24-13. AD notes issued after January 1, 2000, have the two-digit year designator changed to a 4-digit designator, e.g., 2000-01-01.

The big picture

As an AI, I'm delighted when an airplane's records are well organized and annotated. When I see sloppy or poorly organized records, I cringe and hope the airplane is in better condition than the paperwork.

What I'm looking for when I check an airplane's AD compliance record is a list of every applicable AD and detailed notes on what action was taken to comply with each. I want to see a notation for every AD that's ever been listed. If some of the AD notes listed in the index don't apply to the airplane I'm working on, I want to see the notation D/N/A (shorthand for does not apply) written in the "method of compliance" box on the compliance worksheet. That way I know that the AD hasn't been ignored or missed.

A section of the aircraft records must be dedicated to AD recordkeeping. The four main categories of ADs are airframe, engine, propeller, and appliances. Each category has two sections. The first lists all the ADs that can be complied with by a single action. These are called one-time ADs and, after completion, do not require further attention.

The second section lists the ADs requiring recurring action. Most recurring ADs require a complying action at every 100 hours or at each annual inspection. Others may require the action at a future calendar date or accumulation of engine or airframe hours. AD 96-09-10, which addresses Lycoming engine oil pumps, is an example of an AD with a future compliance date. This AD requires replacement of oil pump parts "at the next engine overhaul, or within five years of the effective date of this AD." Although this is a 1996 AD, as long as the owner didn't overhaul his engine before July 15, 2001, he could continue to operate his airplane up to that day and still be in compliance with the AD.

The layout

To make your own list, start by creating a page or template with a header for the component name (such as airframe, engine, prop, magneto, carburetor, vacuum pump, or prop governor) and its make, model, and serial number.

Each page should have a series of columns for entering information. Common forms have headings listing the AD number, amendment number, title or subject of the AD, the method of compliance, two narrow columns for noting whether the AD is one-time or recurring, date and time of compliance (tachometer, or component time since new or major overhaul), date and/or hours that next inspection is due (if recurring), and space for the signature and certificate number of the person certifying compliance. Starting with the oldest AD note that applies, list the ADs in order down the page.

Sounds simple, doesn't it? If your mechanic has created a detailed list using a CD-ROM — available from firms such as Aircraft Technical Publishers, Avantext, Summit Aviation, or Tdata — you may be OK. But I'd double-check even the best-organized list.

The Catch-22

If you're interested in creating your own list, here are a couple of hints. You can access all the ADs by going to the official government Web site ( Here you will find an index for each type of airplane by specific model number, e.g., Cessna 172E. If you own a Cessna 172E you may think that all you have to do is check all the ADs listed in that index. Wrong! There also will be an index for the Cessna 172 and one for the Cessna 172 series. All of the ADs listed in each of these indexes must be checked against the airplane. I don't know why things aren't simpler, I just know that all possible listings must be checked.

For another example of the same Catch-22 scenario, let's take a look at all the indexes for the Lycoming IO-360-A1B6 engine. There are five different Lycoming indexes that must be checked. They are as follows: all series, O-360 series, IO-360 series, direct-drive piston-engine series, and an AD listed under all four-cylinder equipped with rear-mounted prop governor and external oil line. Simple? No. Required? Yes.

Ex post facto

Even an AD that, at first glance, doesn't seem to apply to your airplane could affect you. For instance, AD 71-09-07 R1 (the R1 means that it's been revised once) directs the owners of all turbocharged Cessna single-engine airplanes to pressure test their cabin heaters for leakage every 50 hours. The applicability section of the AD lists serial and model numbers of Cessna turbocharged singles produced as early as 1966. The FAA thought this AD was so important that it was made retroactive to cover turbocharged Cessnas produced before 1971. Are these retroactive AD notes unusual? Yes. And they illustrate that nothing can be taken for granted when researching AD notes.

Owners who don't have access to a computer can order a list of ADs from AOPA's Title and Escrow service at 800/654-4700 or 405/682-2511. Many mechanics will allow owners to use their libraries to do AD research.

The AD book

One reason a shop may charge more for the first annual inspection on an airplane that they have not seen before is because of the time it takes to ensure AD compliance. How does a mechanic know about all the obscure AD notes that apply to an airplane? Mechanics (and owners) who haven't studied the format of the indexes and who aren't familiar with all the components listed in the appliance indexes may miss an important entry. For instance, there's an AD on paper inlet-air filters that mandates the installation of a new filter at 500 hours time in service.

The point is that every component has the potential to be affected by an AD. I doubt if there's an AI who hasn't found at least one AD that hadn't been complied with or was complied with incorrectly. These inspections aren't rocket science — they're just time consuming.

Keeping current

Once the book is set up with the four categories — and the one-time and recurring divisions of those categories — how does an owner keep up with his AD responsibilities?

Usually, the registered owner will be notified by mail of new ADs that may affect his aircraft. However, owners who have recently bought their airplanes or who have changed addresses may be out of the loop for up to a year while the FAA's aircraft registry office catches up with the change. You can keep up during such a transition by visiting the FAA Web site . Type-specific clubs are knowledgeable about the ADs affecting their airplanes and post this information on their Web sites.

The scope of topics covered by ADs has been expanded from focusing exclusively on mechanical items into areas that can't have been foreseen by those who created the AD process.

Following the October 31, 1994, crash of an ATR 72 that went out of control while holding in icing conditions over Roselawn, Indiana, the FAA conducted an extensive study of in-flight icing (see " WxWatch: Winter Wise," page 109). Based on what it found, AD notes were issued for a wide variety of high-performance single and twin-engine general aviation airplanes (98-04-26 for the Piper PA-46-310 and PA-46-350, for instance). These AD notes require an amendment to the airplane pilot's operating handbooks (POHs). ht requires pilots to "immediately request priority handling from ATC to facilitate a route or altitude change to exit from.severe icing conditions." To my .nowledge that AD is the first one written that mandated operational reactions by the flight crew or pilot of a general aviation airplane.

The tone of AD notes has also changed since 1947. The semi-technical ADs written in the 1940s and 1950s were replaced by directives that, over time, gave less information on compliance procedures. Instead, convoluted legalese directed the owner to comply with the procedures in a manufacturer's service bulletin. Recently, the FAA has replaced the legalese with a plain-language format. Spend a few minutes reading ADs from different eras and you'll see what I mean.

Owners who take responsibility for organizing their airplanes' AD compliance records will help lessen the cost of annual inspections and gain insight for planning future maintenance.

E-mail the author at [email protected].

An AD Campaign

Sources for help in building and maintaining an AD list.

AeroTech Publishers Inc., Post Office Box 1359, Southold, Long Island, New York 11971-0965; telephone 800/235-6444 or 631/765-9375; fax 631/765-9359;

Aircraft Technical Publishers, 101 South Hill Drive, Brisbane, California 94005-1251; telephone 800/227-4610 or 415/330-9500; fax 415/468-1596;

AOPA Aircraft Title and Escrow Service, 4300 Amelia Earhart Lane, Oklahoma City, Oklahoma 73159-1140; telephone 800/654-4700 or 405/682-2511;

Avantext Inc., 340 Morgantown Road, Reading, Pennsylvania 19611; telephone 800/998-8857 or 610/796-2383; fax 610/796-2392;

Summit Aviation Inc., Post Office Box 759, Golden, Colorado 80402-0759; telephone 800/328-6280 or 303/425-5994; fax 303/425-7138;

Tdata Corporation, 60 Grace Drive, Powell, Ohio 43065; telephone 800/783 2827 or 614/885-1169; fax 614/885-4342;