Non-annual inspections

The annual inspection for my Warrior is approaching.

As I’ve mentioned before, as a Canadian private aircraft owner, I have the final responsibility for determining that the annual inspection has been completed. In the U.S., on the other hand, it’s not the private owner but an Inspection Authority (IA) who makes that determination and signs a logbook entry returning the plane to service after the inspection. In both countries, of course, the pilot is ultimately responsible for airworthiness before each flight, no matter who has written and signed what in the logs.

In Canada, the Aircraft Maintenance Engineer (AME) performing the annual inspection will typically follow CAR 625, appendix B: part 1 lists a set of standard inspection tasks for any small airplane, such as testing cylinder compression or the torquing and safety wiring of propeller attachment bolts. However, most aircraft manufacturers also publish a customized inspection list for each aircraft, that goes into more detail and includes additional tasks (unfortunately, the manufacturers’ inspection lists are rarely, if ever, available free online).

I’m skipping the 100 hour/annual inspection here, since it isn’t all that different than the generic one in the CARs (aside from a bit more detail). What is more interesting is that the checklist for the PA-28-161 Piper Warrior II includes tasks for 50 hours (i.e. at each oil change), 500 hours (~4-5 years), and 1,000+ hours (~8-10+ years), all inspections not specifically covered in the CARs and not necessarily familiar to owners. I don’t agree with all of these — for example, I’m not automatically going to recondition a fixed-pitch propeller at 1,000 hours if it’s still in excellent shape — but overall, these look like intelligent recommendations, and I’m going to try to make space for them in my maintenance planning. At best, I might avoid a forced landing or worse; at a minimum, I’ll be able to pass on a better-maintained plane to the next owner, and will be able to hold my head up during the prepurchase inspection.

The 50 hour inspection

This one looks huge, but most of the tasks are simple ones, and a good number qualify as elementary work (I’ll post on that in the future). Some of these are things any pilot would do before every flight, such as checking the tire pressure, oleo extension, and alternator belt, and others are part of a normal oil change, like draining the sump or cleaning the plugs. Because my Warrior is blessed with a fully-opening cowl (rather than just a tiny oil door), I can also perform a good visual inspection of the engine, hoses, sparkplug leads, and engine mount before every flight. Still, there’s a lot here that is not part of my normal 50-hour oil change. If I’m changing the oil anyway (say, in the late fall), and already have the plane up on jacks to remove the nosewheel fairing, I think it might make sense to pay for 2 hours or so of an AME’s time to perform the other tasks in this list. It looks like a relatively easy way to maintain a safe plane, and a lot less expensive than the questionable fairy-dust-style safety expenditures many owners make, like backup vacuum pumps (for fixed-gear planes) and traffic alerting systems.

  • Inspect [propeller] spinner and back plate for cracks.
  • Inspect [propeller] blades for nicks and cracks.
  • Remove and inspect engine cowling for damage.
  • Drain oil sump.
  • Clean suction oil strainer at oil change. Inspect strainer for foreign particles.
  • Clean pressure oil strainer or change full flow (cartidge type) oil filter element. Inspect strainer or element for foreign particles.
  • Inspect oil lines and fittings for leaks, security, chafing, dents, and cracks.
  • Fill engine with oil per information on cowl or service manual.
  • Inspect spark plug cable leads.
  • Inspect rocker box covers for evidence of oil leaks. If found, replace gasket, torque cover screws 50 inch-pounds.
  • Inspect condition of carburetor heat air door and box.
  • Inspect all air inlet ducts and alternate heat duct.
  • Remove, drain, and clean fuel filter bowl and screen. (Drain and clean at least every 90 days.)
  • Inspect condition of flexible fuel lines.
  • Inspect exhaust stacks, connections and gaskets. Replace gaskets as required.
  • Inspect engine mounts for cracks and loose mountings.
  • Inspect condition and tension of alternator drive belt.
  • Inspect security of alternator mounting.
  • Check condition and security of hydraulic line and fluid in brake reservoir; fill as required.
  • Reinstall engine cowl.
  • Check landing, navigation, cabin and instrument lights.
  • Inspect battery, box and cables (Inspect at least every 30 days). Flush box as required and fill battery per instructions on box.
  • Remove, drain, and clean fuel strainer bowl and screen. Drain and clean at least every 90 days.
  • Lubricate [fuselage and empennage] per lubrication chart.
  • Check emergency locator transmitter battery replacement date and transmitter for operation.
  • Lubricate [wing] per lubrication chart.
  • Inspect oleo struts for proper extension (N-3.25 in./M-4.50 in.). Check for proper fluid level as required.
  • Check tire pressure. (N-30 psi, M-24 psi.)
  • Lubricate [landing gear] per lubrication chart.
  • Inspect all hydraulic lines and attaching parts for security, routing, chafing, deterioration, wear, and correct installation.

The 500 hour inspection

The 500 hour inspection includes only three tasks not already in the 100 hour/annual inspection:

  • (400 hours) Remove rocker box cover and perform a valve inspection.
  • Remove and flush oil radiator.
  • Replace auxiliary vacuum pump.
  • If installed, replace central air filter.
  • Clean and lubricate stabilator trim drum screw.

I have my stab trim screw cleaned and lubed regularly because it becomes stiff in cold weather, but I can find no record of the oil cooler ever having been removed and flushed — any gunk caught in it can circulate back into the cylinders, wearing them down and forcing an early overhaul; this year, I plan to have this work done as cheap insurance for my engine. I don’t have an auxiliary vacuum pump in the plane, only the main engine-driven one.

The 1,000+ hour inspection

There are only a few 1,000+ hour tasks:

  • Recondition propeller.
  • Replace magneto.
  • Overhaul or replace engine driven and electric fuel pumps.
  • (2,000 hours) Complete overhaul of engine or replace with factory rebuilt.
  • Replace engine driven vacuum pump.
  • Clean and lubricate all exterior needle bearings.

OK, now it’s time to be realistic. I am not going to replace my engine at 2,000 hours if it’s still going strong. In fact, I think that doing so would actually be more dangerous — the only forced landing I’ve ever seen happened right after a new engine was installed, because the shop attached something incorrectly; two other local forced landings I’ve heard about had similar causes. As long as my compressions are good and there’s no metal in the oil filter, I’d rather stick with an engine that has all its bugs shaken out than a new, unproven one. The vacuum pump, on the other hand, is cheap to buy (a few hundred dollars) and easy to install (about 30 minutes of an AME’s time) — I’ve already had one fail on me, and preemptive replacement here might make sense. I’ll have to think about that one.

Just in case anyone has the mistaken idea that I — who, as a teenage boy, preferred reading books to fixing cars — actually know much about nuts-and-bolts (so to speak) of maintenance, I’ll finish with a simple question: What’s a needle bearing?

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10 Responses to Non-annual inspections

  1. Paul Tomblin says:

    I’m surprised you’re so dismissive of a backup vacuum pump (and what does it have to do with whether your gear is fixed or not?). Many people say they won’t fly real IFR without one. It’s hard to think of a single item that is both so fragile and so likely to kill you if it fails as the primary vacuum pump.

  2. David Megginson says:

    Can you point me a single accident — fatal or otherwise — caused by the loss of a vacuum pump in a fixed-gear plane flying IFR? So far, I’ve come up empty looking in both Canada and the U.S., though I’m sure that one or two must have happened somewhere. As far as safety goes, I think there are many more productive areas to spend your money.

    It’s a different story for retracts, of course, since they can spiral out of control so fast (unless you lower the gear to add some drag).

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  4. Thomas Cain says:

    I am confused regarding the perfor,mance of a such an indepth 50 hour inspection and so little oncern for the 100 hour inspection. I have worked warriors for 25 years. In that time I have found thaht the moset import tasks are cleaning the spark plugs, changining the oil and filter, and lubricating pivot poits and spraying electroncic cleaner in the starter. Jusy mu thoughts.

  5. Dio Santos says:

    is very nice the information,you posted,but you forget to put pre-buy inpection and also fase out.
    best regards

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  7. Niss Feiner says:

    How much does an anual usually cost? And I am probably correct in saying that it must be performed once a year hence the term annual?

    Its been a couple of years since my ground school LOL


  8. david says:

    From what I’ve seen and heard, the actual annual inspection will typically cost CAD 600-1,200, depending on what it covers and how thoroughly it’s done. Unless it’s owner-assisted, the CAD 600 annual will be pretty minimal. There are two ways to go for the Warrior (I’m not sure about the 140) — Transport Canada publishes a minimal inspection list that most of the fixed-price inspections use, but Piper also publishes a much more detailed one.

    When most people talk about an “annual”, though, they mean not just the legally-required inspection but all of the repair and maintenance work that they save up and do at the same time. The inspection will always show up some airworthiness issues, as well as some preventative maintenance issues that you decide to take care of before they get too expensive, and new or recurring Airworthiness Directives may also require extra work. I’ve heard of annuals (in the broad sense) go as high as CAD 10,000 for a fixed-gear plane (a Cardinal, in that case), but maybe CAD 3,000-4,000 is more typical. You can get a cheaper annual by doing a lot of the work yourself under the supervision of a sympathetic AME, if you actually know how to handle tools and do repairs (most of us owners are not as good as we think we are), or by deferring as much as possible and hoping that you’ll sell the plane before it breaks. You’ll always defer some items, though, especially ones that wear slowly and predictably, and will keep a running list of things you plan to replace next year or the year after.

  9. Niss says:

    David – Thanks again for the info. Is the annual scheduled by years or by hours?




  10. david says:

    For privately-registered aircraft, the annual is scheduled by calendar time (every 12 months), but is often referred to as a “100 hour inspection”. There are also a couple of things that happen every two years, such as having your ELT and transponder mode C checked. You should change your oil every 50 hours flying time or six months (whichever comes first), but that’s not a regulation, and you can do the changes yourself if you want (again, that’s on a privately-registered aircraft, not a commercially-registered one).

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