We’ve all been very distracted and entertained by the recent FAA Airworthiness Directive issued against the power lever on our Cirrus SR series aircraft. In following a couple of the forum threads relating to it, I noticed some voids in the understanding of Airworthiness Directives (AD) on which I may be able to shed some light.

According to Title 14 Code of Federal Regulations Chapter 1 Subchapter F Part 91 paragraph 91.403(a) “The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition, including compliance with part 39 of this chapter.” (I’ll shorten to CFR 91 or similar going forward).  Part 39 is Airworthiness Directives and you, the owner/operator, are THE person tagged by the FAA as responsible to ensure that all ADs are complied with, not your mechanic.

It is true, and acceptable, that owners subcontract the AD research to their maintenance providers during an annual inspection. That works out fine because CFR 43 paragraph 43.15(a) (1) tells the inspectors to “Perform the inspection so as to determine whether the aircraft, or portion(s) thereof under inspection, meets all applicable airworthiness requirements…”.  However, this is only during inspections, not routine maintenance events. Oil changes, tire changes, engine repairs, software updates are all routine maintenance covered by CFR 43.11 and does not trigger an automatic aircraft wide airworthiness check with AD compliance or research. When the FAA issues an AD that might apply to your airplane, maintenance providers are also not responsible to inform you outside of an annual inspection.

Maintenance is only responsible to research ADs if they are contracted by the owner/operator to perform an inspection, such as an annual or required 100 hour.  Any routine repairs or servicing does not trigger an automatic AD compliance or search on the maintenance provider’s part.

The FAA website www.faa.gov has all ADs available for anyone to search and read. It can be a challenge to navigate, but everything is there, somewhere.  There’s no magic to reading an AD, just some patience. Compliance times can be confusing as well as compliance procedures. I’m not totally clear on how the content of an AD is produced, but I suspect several people are involved from various disciplines. The way most of these are written, it seems likely that mechanics, pilots, or English teachers were not consulted for proof reading.

The first paragraph to read on an AD is “Applicability”. This determines if it’s worth your time to read any farther. For the power lever AD applicability, it is important to note that it doesn’t call out any limited serial number group of Cirrus SR series aircraft. The subject of the AD is three specific part number power levers. These power levers are only installed on certain versions of Cirrus with certain avionics options but identifying by aircraft model and serial number could cause issues. While not a likely concern, it is possible that someone purchased an affected power lever from a salvaged aircraft to install in a legacy aircraft with updated avionics. This would give the capability of a “go around” switch in the power lever handle just like the newer planes have. This unlikely but very possible scenario is why the FAA identified the power lever as the subject of the AD instead of the aircraft.

There are four categories for Airworthiness Directives. A proper and complete research should include the airframe (Cirrus), engine (Continental), propeller (probably Hartzell) and accessories. Seems a lot of people forget about accessories which include things like magnetos, cylinders, brakes, GPS, autopilot servos, coffee makers, ignition switches, circuit breakers, etc.  Just because an accessory is attached to an engine does not always mean it is included in the engine AD search, just as avionics are not included in the airframe AD search. I recommend an owner/operator ask the maintenance provider to produce a detailed list of all the items, including accessories, that are part of their AD research. This ensures that the accessories are appropriately checked as well as the easy big three of airframe, engine and propeller. FAA Advisory Circular 39-7D is an excellent review on AD responsibilities for the aircraft owner/operator.

Contrary to popular understanding, ADs do not all conveniently come due during annual inspection. While the recurring AD might have a 12 month cycle, it is not directly connected to the scheduled annual inspection.  An annual inspection does not include AD compliance for the following year. The aircraft is declared airworthy only as of the date of the signature with no forward-looking requirements at all.  An annual can be legitimately signed off as airworthy with the newly issued power lever AD 2024-24-11 inspection required the next day or one flight hour away.

As the responsible owner/operator in charge of airworthiness, you want to know what the log entry should include. CFR 43 paragraph 43.9 gives the basics for a standard maintenance sign off. For an AD, you want more details than just the basics.  The description of the work performed should include the specific paragraphs of the AD that were complied with. The time of the next required compliance must also be included if it’s a recurring AD.

My version of the power lever AD compliance record entry looks like this:

“AD2024-24-11 amendment 39-22902 effective date December 23, 2024 complied with paragraph (g)(1) by initial visual inspection and paragraph (g)(3) by fluorescent dye inspection. No cracks or defects found at this time and report sent to FAA. Next due by AFTT: xxxx.x”

An odd detail is that the FAA requires mechanics to include the “revision” date of the AD in our entries. The odd part is that there is no reference on any AD to a “revision” date. The closest verbiage is the “effective” date, which is what we use.

I include the statement about sending the report to the FAA in part because the reporting is a requirement of this particular AD and reporting is part of the description of the work performed. Seems like a silly detail, but it gives an owner/operator some assurance that all the requirements of the AD were met. Reporting requirements are not very common so asking your mechanic to include such in the sign off helps him/her to remember to make the report within the 5-day limit as required by paragraph (h) in the AD.  The report is just a simple email stating this particular aircraft was inspected at this flight time on this date and had these findings. It takes about a minute to do.

Cirrus SR series power lever

FAA Airworthiness Directives and manufacture Service Bulletins (SB) are not the same in terms of regulatory requirement and recommended actions. An AD is always a legal requirement for aircraft airworthiness. For aircraft operated under CFR 91, a SB is not an FAA requirement and only a recommendation from the manufacturer, regardless of how urgent the SB title sounds.  The exception is when an AD references a SB.

An AD will not give a blanket statement that says, “comply with Cirrus SB”. This is because the FAA may have different requirements than the SB. What an AD may do, as it does on the Cirrus power lever AD, is reference specific parts of the SB for compliance. Any part of the SB not referenced by the AD may be ignored. The AD will also reference a specific revision of the SB so a newer version of the SB would not be an appropriate reference when complying with the AD.

Special Note – Just because a manufacturer’s SB is not required for compliance by the FAA doesn’t mean you should automatically ignore it. Every owner/operator should read and understand the implications of an SB to make a good decision as to whether compliance is important to them.

Initial compliance time requirements vary from one AD to another, but all are referenced to the “effective date” of the AD. This may be flight hours or a specific number of days, months or calendar year(s). If some sort of day or calendar time is required, it’ll be measured in the same way as other maintenance tracking or pilot information tracking. For time in service requirements, it can seem a bit more complicated.

Cracks in power levers can be detected through visual and dye penetrant inspections

CFR 1 defines Time in Service. “Time in service, with respect to maintenance time records, means the time from the moment an aircraft  leaves the surface of the earth until it touches it at the next point of landing.  The regulations don’t specify how this time in service is to be recorded or tracked.  Most legacy aircraft still use a mechanical tachometer as the sole recording device. Its clock speed changes based on engine speed but certainly didn’t start and stop as a result of aircraft flight. Some aircraft have an hour meter that is triggered by an oil pressure or an airspeed switch or even landing gear position for those with retractable undercarriage. Still, not technically complying with the definition of leaving the earth to touching the earth again (let’s don’t even think about a bounced landing with multiple touches). My SR22 G1 had a single HOBBS hour meter when I purchased it, but I’ve since upgraded to a more modern glass panel. The new hardware tracks Flight Time, Hobbs Time and Tach Time. I use the one that shows the least amount of time which happens to be Flight Time.

In the real world, the slowest recorder of time in the aircraft is going to be the one to use for tracking maintenance. If it isn’t actual flight time, it’ll be the one closest to true flight time. It’s very common to track maintenance by Flight and rental time by Hobbs. It’s also perfectly legit to track times using your watch or other time piece. Just note the takeoff time and the landing time and keep those recorded. You’ll find this method to be a problem when it comes time to sell the plane, but I’m just putting it out there so we know there are multiple acceptable ways of tracking time.

Due to the short leash the FAA put on initial compliance with the power lever AD, by the time this article is published, most of the fleet with 1200+ hours of time in service will have completed the initial compliance inspections.  We’re all very hopeful that Cirrus will produce a replacement part with a different design and different part number to be installed as terminating action. We’re also very hopeful that the reporting requirements to the FAA will result in a change in the recurring time requirement for repetitive inspections. The 110 hours is an odd and very restrictive requirement which is not likely to be supported by the evidence. Hope springs eternal.

©Paul New 2025