An Accessory to the “Crime” or

Standing on My FAA AD Soapbox

I heard a preacher tell a story of a parishioner who complained about too many duplicated sermons. Apparently, the same message was repeated several services in a row, and the parishioner was getting pretty tired of hearing all the bad stuff that he shouldn’t be doing. The preacher calmly responded that as soon as the congregation responds to the warnings, he’ll move on to a new topic. I feel a little like that preacher when it comes to proper FAA Airworthiness Directive research (Reference my article for the CPA magazine June 2007 titled “Paper Airplane”). I hope you’ll forgive me for  beating this horse again, but I can tell it isn’t quite dead yet.

I continue getting new owners in my shop with “new to them” airplanes that are not in full compliance with FAR 91.403 which puts the owner in charge of the aircraft’s airworthiness, including compliance with FAR Part 39.  These aren’t suggestions or guidelines; this is the FAA Regulation stating you, as the aircraft owner, are REQUIRED to have the plane in compliance with FAR Part 39.  Unfortunately, many aircraft owners have no idea what FAR Part 39 is or how to tell if they are in compliance.

The FAA requires pilots train extensively on how to fly and includes recurrent training to be sure they stay on top of their game. For some reason, that same conviction doesn’t hold for training future or current aircraft owners about the FAA requirements of aircraft ownership. This article is my attempt to provide you with enough information to make a good effort toward ensuring your plane is at least in compliance with the Airworthiness Directives ­ aka FAR Part  39

Most owners subcontract the AD research to an FAA certificated A&P mechanic with Inspection Authorization whom one assumes will do a proper detailed job.  The vast majority of inspectors do an excellent job. Unfortunately, there are some inspectors that don’t fully grasp the depth of effort required and ignore some areas of research.

Some owners employ a company called AdLog to keep up with your airworthiness directives. The AdLog system is very convenient and an excellent service overall, but it’s only as good as the information the aircraft owner provides..  By their own admission, AdLog is not an AD research company, they are a records keeping company.

AdLog will ask a new client to complete a checklist of particular components on the plane. This is where the system loses some continuity. AdLog knows what the most likely items are that need to be recorded, but they don’t have access to the actual airplane.  The owner has access to the plane but doesn’t always understand the need for detailed and complete information. Adlog also has a very good idea what was standard installation on a plane when it was built but no idea what’s been done to it in the last thirty years. A really good listing of all the accessories on the airplane is the common missing link.

The use of AdLog doesn’t negate the need to include the inspector in the process. Missing an AD is a serious offense for an inspector, so they will not likely, and shouldn’t, just accept whatever Adlog data the owner might present. The inspector’s signature at the end of the annual inspection entry puts almost all the liability for the AD research on his/her shoulders. Your inspector  will need reasonable evidence that all needed information is correct. Adlog does not currently supply a listing of all the components included in their research. As a minimum, the owner could give the inspector a copy of the AdLog checklist that was filled out when the service was initiated.


There are four categories for Airworthiness Directives. They are airframe, engine, propeller, and accessories. An accessory can be most anything attached to an airplane that isn’t the airframe, engine, or propeller. However, an accessory can be a part of any of those other three categories. An example will help explain the misunderstanding.

Let’s imagine your forty year old Cessna 182 was delivered with a Continental O­470 engine, and that is reflected in the AD research listing.  The current AD research accessory listing may not accurately reflect the last 4000 hours and four decades of changes to that engine. Instead of the original Continental parts, the current engine may have some ECI cylinders, Superior pistons and piston pins, Slick magnetos, shower of sparks ignition, S­Tec starter. None of these items show up in the engine category search under Continental.  This is entirely normal, as all of these engine components would be found in the accessory category. They won’t get searched if they’re not documented in the accessory listing.

The airframe is loaded with more diversions from its original equipment list than the engine. Your accessory search list should include airframe related items such as GPS, transponders, autopilots, nav/com, altimeters and airspeed indicators. There are several seat belt ADs that are not covered in the airframe category. If your belts don’t have data tags or plates, you won’t be able to confirm they are certified parts, much less determine if any of the ADs apply.

My favorite and most commonly found accessory miss is the ignition switch. It’s often assumed a Bendix brand ignition switch is installed, which can have a 100 hour recurring requirement for an operational check. We find the AD compliance dutifully recorded in the maintenance record entries every 100 hours for the last 35 years.  After actually looking at the switch to complete a proper equipment list, we find an ACS brand switch is installed with a 2000 hour recurring AD requirement for disassembly and lubrication. Assuming the ACS switch is an original equipment part, these planes have been flying around in an unairworthy condition for a long time.

Research Software

There are several companies providing Airworthiness Directive research software. All are very good and are designed specifically to assist the AI in the task of finding all the possible ADs that might apply.

The software I use breaks down the accessory category into many subcategories. These subcategories have some fairly unexpected titles: tires, heaters, ignition systems, coffee makers, fire extinguishers, turbochargers, wheels, brakes, servos, air filters.

Other software might list accessories by manufacturer. Some unexpected names include Kollsman (altimeters), Rapco (pneumatic pumps and other stuff), Shadin (fuel totalizers), Leigh Systems (ELT), Garmin (GPS, transponder, autopilot), United Instruments (altimeter), Whelen (lighting), Wood Electric (circuit breakers), and even Briggs & Stratton (ground power generators).

The FAA allows research software to parse directives using the components manufacturer name, the model, and/or component part number. They do not allow software search down to serial number but instead leave that to the reader.

Be an Accessory to the Solution

Aircraft owners are likely the least trained to gather the information needed to generate this listing of components.  FAA certified mechanics with Inspector Authorization are the ones generally tasked with this effort, and they get almost no official training in this matter either.  I am continually amazed at how many new clients’ airplanes arrive at our shop with documentation showing only the airframe, engine and propeller have been searched. There is often no mention of accessories at all.

As the owner you can, and should, get very involved in the Airworthiness Directive research on your plane. Step one is to create a comprehensive list of all the possible components on the airplane for the research. If you subcontract this effort to your A&P with Inspector Authorization, he/she should supply you with a list of everything included in the research.  It should be a pretty long list with many items that may not have any ADs against them.  This is at least one way to have some confidence a good search is done.

As an industry, we make a big “to do” discussing whether manufacturers’ mandatory bulletins are truly FAA required. Some will spend an exorbitant amount of time researching the bulletin and starting a new thread on the forums just to explore potential options. A small amount of that effort would easily generate a proper equipment list and AD research.  We should be at least as interested in keeping the plane safe and FAA airworthy as we are in being cost efficient with bulletin compliance.  I may check back in another five years to see how we’re doing, but I’ll step down off my soapbox for now.

Copyright © Paul New 2013. All rights reserved.