Last week I was at a shop doing a clinic on engine rigging with the maintenance technicians. Conveniently, there was a King Air in the shop with engine rigging issues, and everyone benefited from the hands-on experience. We also looked at the other King Airs in the shop. We discussed squawks that had been found and how best to troubleshoot and remedy them.
One King Air had a highly unusual maintenance background – somewhere between intermittent and non-existent. The owner acquired it eight or nine years ago. It was based in the western U.S. and made frequent trips to Mexico. Reportedly, at one point it flew for three years with zero maintenance! I’ve seen my share of airplanes that were parked for an extended period during which maintenance was deferred but to fly regularly for three years with no maintenance at all is just plain crazy.
They were finally getting all the maintenance caught up, so this King Air was on its third visit to that shop. I’m told the owner bought it from a buddy who told him “everything worked” on the airplane, and that was it. Clearly there was no pre-buy inspection. At the very least, I would have expected the new owner to think his newly acquired aircraft needed an annual inspection.
King Airs don’t get “annual inspections”
I’ve worked with aircraft owners acquiring their first King Air for decades. Many are transitioning from the piston to the turbine world; therefore, they are firmly dialed in on the FAA-required annual inspection. And because some maintenance items on a King Air come due every 12 months, new King Air owners keep calling maintenance requirements “an annual.”
It’s just a nomenclature issue, but the difference is important. Normally I don’t kick up a fuss about the proper term for this or that, but when it comes to “annual” versus “phase” it is a sticking point for me.
An annual inspection, as specified in FAR Part 43, is performed by a licensed aircraft mechanic, but it must be signed off by an authorized inspector (an A&P who also holds an inspection authorization certificate). IA certs must be renewed regularly.
The four phases
Phase inspections on a King Air are part of a factory-recommended program per 91.409(f)(3). An IA certificate is not required for the logbook sign-off. There are four phase inspection checklists, and all four must be completed in a 24-month time span. Additionally, if a King Air does a lot of flying, a phase must be done every 200 hours (more on that later).
Each phase has a checklist of items to be inspected. The phases are not identical. Some basic inspection items are repeated at every phase, but each checklist has inspection items unique to that phase. All four phases must be done every two years to maintain airworthiness.
There are a variety of special inspections that also apply to the various King Air models. Compliance requirements can be hour-based, calendar-based or they may come due after a certain number of landings (cycles).
I have weaned many a new King Air owner off the “annual inspection” idea and got them thinking in terms of phase inspections, special inspections and tracking cycles in addition to hours.
The alternate phase inspection program
Most King Airs out there (Part 91, at least) are on the alternate phase inspection program. Phases 1 and 2 are done one year and phases 3 and 4 the next, and so on. Provided your average use stays around 16.5 hours/month or less, you qualify for this plan. The calendar requirement of all four phases in a 24-month period trumps the 200-hour requirement in this case. Since you’re doing two phases every year, it may seem like an annual inspection on a piston aircraft, but it is not.
In addition to the phases being done, there are special inspections coming due at every phase inspection visit. Some of these are 12-month items such as the capacity check on the battery or the ELT (emergency locator transmitter) check per FAR 91.207(d). 
Other special inspections come due every 24 months, such as your avionics check (the pitot-static and transponder checks, aka the 411/413). The engine nozzle clean and flow check is a 400-hour item. Special inspections of the landing gear are often cycle-based (1,000-cycle inspection of the main gear and nose gear clevis) or are a cycle/calendar combination (actuator end-play and lube at 1,000 cycles or 30 months, whichever comes first).
The 200-hour phase inspection program
High-use King Airs must do a phase every 200 hours. King Airs that fly around 33 hours/month or more fall into this category. At this use rate, a King Air could get all four phase inspections done, one at a time, in a 24-month period. Completion of the four phases every two years is a requirement for all King Airs, no matter how much or how little they fly. When average use fluctuates between 17 and 32 hours/month (approximately), you have to keep an eye on that 24-month deadline and plan how to get all four phases done.
Here’s an example with a King Air averaging 22 hours/month: They do a Phase 1 and fly 200 hours over the next nine months. They do a Phase 2 and fly another 200 hours over another nine months. Now they are 18 months into the 24-month period. There are six months left and phases 3 and 4 still need to be completed. They can do phase 3 now and put it down again after six months for the phase 4; or they can do the phase 3 plus the phase 4 right then and not have to put the aircraft down for another 200 hours. The 24-month parameter resets from that point. Either choice is correct but the latter saves downtime.
Why can’t I do a phase 1-4 every other year?
You can! Beech calls it the biennial inspection program.
There are three requirements to be eligible for this program:
First, are you flying fewer than 200 hours in a 24-month period? That’s an average of 8.5 hours per month or less. This program is for low-use King Airs.
The second requirement is an interim inspection at the 12-month mark in alternate years between the biennial phase 1-4. There’s a checklist for it in the maintenance manual. Essentially, it’s a thorough operational check on the aircraft. Of course, any discrepancies noted must be remedied.
The third requirement is a declaration in your logbooks that the aircraft is on the biennial inspection program. You can’t go two years without a phase and then suddenly decide you are doing the biennial program.
I don’t come across many King Airs on the biennial program, but when I do they are usually in bad shape. Often, the interim inspection hasn’t been done or if it has, it’s been pencil-whipped. Special inspections are ignored or glossed over. Too many owners think it’s a Phase 1-4 every other year and little else. Following the biennial program correctly with interim inspections, special inspections, etc. doesn’t save much money in the long run. I’m not a fan.
I’ve had many low-usage customers who could qualify for the biennial program, but they chose the alternate phase inspection program (two phases each year, completing all four phases in 24 months). When they go to fly their King Air, they want to have confidence in it. They prefer an airplane that is looked at regularly and thoroughly. The less they fly, the more they want this assurance.
Whatever inspection program you use should be declared in your logbooks.
Special inspections and MORE
Regardless of which inspection program your King Air is on, you can see that King Airs have quite a few components subject to special inspection, overhaul or replacement. For example, the hydrostatic test on the oxygen bottle is calendar-based, due at 36 or 60 months depending on your bottle. The instrument air filter replacement is hour-based at every 600 hours. Your starter generators need to be sent for overhaul every 1,000 hours. Replacement of the flap flex shaft is cycle-based, due every 5,000 cycles.
Likewise, major items like landing gear, props and engine maintenance are not covered by the phase checklists. If you have an engine on the MORE program, additional maintenance requirements are specified by that program. The MORE program (Maintenance On Reliable Engines) is a supplemental type certificate that comes with its own manual. Detailed checklists of engine maintenance items are included. It is very clear, and it all must be done.
STCs and your POH
King Airs have been around for a long time. There are lots of FAA-approved modifications and upgrades that can be done. Propellers can be changed (four-blade or swept-blade), engines can be changed (as in a Blackhawk conversion) and, of course, Raisbeck offers many performance-enhancing upgrades. All such modifications or STCs have operational and maintenance instructions that must be followed to maintain airworthiness.
They come with the STC paperwork and are known as the instructions for continued airworthiness, or the ICA. STCs, with their corresponding ICAs, are kept in the supplements section of the pilot operating handbook. This is a vital point! The airworthiness of your King Air depends on the applicable ICAs being followed. The ICA supersedes the maintenance manual and gives the pertinent maintenance requirements for that modification. If you put Commuter Air Technology’s Soft Touch Tires on your King Air, don’t look in the manual for tire pressures. Soft Touch Tires are STC’d so to service them correctly, check the ICA.
This is really important. Not every shop is familiar with King Airs. Time after time I find well-meaning mechanics following the maintenance manual without realizing the item they are working on is an STC modification with an ICA in the POH. The mechanic remains focused on the MM, unaware they are making incorrect settings or adjustments. On two separate occasions I had to condemn a pair of four-blade props because the mechanics set the low idle improperly. They followed the MM, which applied to the three-blade props original to the aircraft. The four-blade props were an STC’d upgrade, and the proper low idle setting was in the ICA.
Maintenance tracking
Keeping track of these calendar, hour and cycle requirements may seem overwhelming, but it doesn’t have to be. When I had my shop, I tracked the maintenance status for King Airs that came to me on a regular basis. I developed a simple three-page form showing the required maintenance items, when they were last done (date, hours or cycles) and when they were next due (date, hours or cycles). At the end of every phase, I debriefed my customer on everything accomplished in that maintenance visit and gave them an updated status sheet. Customers loved it. Pilots flying multiple King Airs went home and made their own Excel spreadsheets for each King Air they flew.
Many shops do something along these lines for their regular customers. I did it at no charge, except for the first visit, which required extensive logbook study to ascertain the maintenance status of that King Air, and I charged a nominal fee for that.
There are, of course, maintenance tracking services and you’ll find several to choose from. They research your logbooks for a baseline report and update it based on maintenance records you provide. Their reports are extensively detailed and can run 100 pages or more. These services are great for managing a flight department with multiple aircraft, but they may seem like overkill for a King Air owner/operator.
You can hire a maintenance manager to keep track of what is coming due on your aircraft. I have done this. My customer (or their pilot) sends me the log entries from the last maintenance visit, I update the status report and I email it to the pilot before he plans the next one.
Bring the logbooks to maintenance
I can’t emphasize this enough: Even if you return to the same shop every time, the mechanic needs your logbooks – and your POH – for reference. Inevitably, when the logbooks aren’t there, something pops up during inspection and your mechanic needs to research something. It’s Murphy’s law. So please, please bring them.
In closing, remember this from FAR 91.403(a): “The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition …” Aircraft owners who are not pilots must take heed of this responsibility. Clearly, the owner of the King Air with no maintenance for three years was remiss. That said, I wish you many happy and safe hours in your King Air.