One of the most frequently asked, and most frequently debated, questions our maintenance team receives is: Which Cessna Citation maintenance items are mandatory, and which aren’t? This is heavily debated because even some FAA interpretations seem to differ when it comes to Cessna’s Part 91 directives.
Today, we’re diving into what is required and what is simply considered “maintenance”. It’s important to note that, at the time of posting this article, all information is accurate to the best of our abilities. As we know with service directives, things can change. It’s important to always talk with your trusted MRO partner about your Cessna Citation, its upcoming inspections, and all airworthiness directives.
Understanding Your Responsibility
FAA regulations state, under Sec. 91.403, that:
- The owner or operator of an aircraft is responsible for maintaining the aircraft in an airworthy condition
- No person may perform maintenance, preventative maintenance, or alterations on an aircraft other than as prescribed in applicable regulations (i.e. a MRO)
- No person may operate an aircraft which a manufacturer’s maintenance manual or instructions for continued airworthiness has been issued, which contains airworthiness limitations unless the mandatory replacement times, inspection intervals, and related procedures have been complied with (as laid out in Sec. 91.409)
- A person may not alter an aircraft based on a supplemental type certificate unless the owner or operator is the holder of that certification or has written permission from the holder of the certificate.
Essentially, this means that, as the owner or operator, it is your responsibility to maintain an aircraft’s airworthiness and comply with all maintenance regulations.
Keeping a piston-powered aircraft airworthy is generally considered straightforward. Most aircraft require an annual inspection, as well as other inspections for vital systems such as the transponder and emergency locator transmitter. Airworthiness and requirements get more complicated, however, when considering turboprops and jets.
Airworthiness Limitations, Defined
Most turbine aircraft have airworthiness limitations as a part of their maintenance manuals. This section is typically found in chapter 4 of the maintenance manual and it lists inspection and parts limits for what determines a safe and reliable aircraft.
According to 91.403(c), if your aircraft has airworthiness limitations in either the maintenance manual or ICA, you must comply with all of the replacement and inspection intervals outlined in those rules—not just an annual inspection.
It’s important that you carefully review your maintenance manual and instructions for continued airworthiness to ensure all inspection and replacement requirements are being followed.
Cessna Citation Inspection Program
There are many inspections that occur at routine intervals for Cessna Citations, but the most comprehensive inspection for the 525 is the Inspection Document 10. The Doc 10 inspection is performed every 36 months, or every 1,200 flight hours, whichever occurs first. With close to 50 tasks, this inspection program assesses a Cessna Citation from nose to tail. During this inspection, aircraft technicians thoroughly inspect the aircraft’s systems and components, and the inspection involves disassembling the aircraft’s interior to check the wiring harnesses and flight controls. Additionally, technicians will inspect the engine and seal the fuel cells.
The inspection tasks laid out in the Inspection Document 10 are mandatory as directed by the FAA and federal regulation, as are all other Inspection Documents laid out in the Cessna Citation maintenance manual.
Mandatory Inspection Tasks vs. Optional Maintenance Tasks
What about the aircraft maintenance tasks that aren’t mandatory? This is, of course, where it gets complicated. Maintenance manuals vary from manufacturer to manufacturer—meaning terminology that is listed in the Cessna Citation maintenance manual may be completely different from terminology written throughout a King Air maintenance manual.
This is what often leads aircraft owners and operators scratching their heads, wondering what is mandatory versus what is simply suggested.
The FAA has weighed in on this, however. In an advisory circular published in 2017 in regards to Part 91 inspection programs, the FAA states that manufacturers will typically provide recommended “maintenance” tasks in addition to “inspection” tasks in the section of their maintenance manual that’s designated for their inspection program (like Cessna Citation Chapter 4). The FAA states that while manufacturers are not prohibited from incorporating those maintenance tasks into their maintenance manuals, they do not fall under the scope of the inspection program and are not mandatory for an operator to include as part of their approved inspection program (AIP). However, if scheduled maintenance items are included in the AIP, they become mandatory and must be accomplished in compliance with all Part 91 regulations.
The FAA generally refers to an inspection program approved under Part 91, which is mandatory, as an Approved Inspection Program (AIP). The AIP term is based on language used in 91.409(f)(4) and (g) where it states, “inspection program…approved by the administrator”. So, as you’re reviewing your maintenance manual, specifically look out for the AIP terminology as a way to pinpoint mandatory inspection items.
As you’re reviewing your Cessna Citation maintenance manual, or any maintenance manual for that matter, be sure to pay close attention to the distinction of inspection programs versus maintenance tasks. Inspection program related tasks will always be mandatory, whereas manufacturer maintenance tasks may not be. In fact, the FAA states that even overhauls are a form of maintenance and are not mandatory for part 91 operators. According to the FAA, overhauls are a form of maintenance, not inspection, and are not included in an inspection program. Overhauls are part of a maintenance program, and part 91 operators are not required to comply with the manufacturer’s entire maintenance program.
Perhaps one of the more confusing aspects of understanding mandatory inspection tasks versus optional maintenance tasks is functional checks. Functional checks can be called for in a number of different situations, which makes classifying them difficult. If a functional check is included in a maintenance program, it is mandatory. However, if a functional check is performed as part of a return to service after a specific maintenance activity, then it falls under a “maintenance task” and not a mandatory inspection program. Functional checks could also be part of an operator’s pre-flight or post-flight check, and not be a maintenance item at all. When considering functional checks for your Cessna Citation, or any other aircraft, reference your maintenance manual. If it is listed in the inspection program, it is mandatory. If it is listed under maintenance, it is a maintenance item and not mandatory (though still recommended).
Manufacturer’s Service Bulletins
Manufacturer’s service bulletins also come into question as to whether they are mandatory or not. For Part 91 operators, compliance with manufacturer service bulletins is not required to be completed within any specific time frame. What is mandatory, however, is that once an operator chooses to perform the service bulletin, they must strictly follow the methods, techniques, and practices described within the service bulletin, unless they are using some other FAA-approved method.
Manufacturer service bulletins are mandatory, however, when:
- All or a portion of the service bulletin is incorporated as part of an airworthiness directive.
- The service bulletin is incorporated directly into an FAA-approved inspection program
- The service bulletin is part of the FAA-approved airworthiness limitation section of the manufacturer’s manual.
Always Consult A Trusted Aircraft Maintenance Technician
We’ve only scratched the surface of what is a mandatory inspection item versus an optional maintenance task. What is outlined above is only applicable to Part 91 operators, and there is an entirely separate set of rules for Part 135 operators.
Always consult a trusted aircraft maintenance technician when navigating the ins and outs of your aircraft’s inspection and maintenance needs. At Winner Aviation, our maintenance technicians have decades of experience and can help you follow inspection guidelines for your aircraft. Talk with us today about your maintenance schedule.