Be an Airplane Detective PDF Print E-mail
Written by Kathie Brosemer   
Wednesday, 18 July 2012 13:14

As a pilot, it’s your responsibility to see that the airplane you’re flying is in airworthy condition. In practice, if it isn’t your airplane, how can a pilot really know? It comes down to doing a thorough preflight inspection, checking the documentation, and trusting that the documents are telling the truth. So, we look for the airworthiness certificate, registration, operating handbook, and weight and balance data (known as AROW documents), and we check the maintenance records. The airplane has to have passed an annual inspection within the previous 12 months and, if a rental, a 100-hour inspection within the last 100 hours of logged time. We look for the ELT check (12 months), transponder and pitot/static system check (24 months), and VOR check if we’re flying IFR (30 days). As long as all of these items check out, and our preflight walk-around doesn’t turn up any snags, we’re saying it’s airworthy.

But according to FAR 91.403, an owner/operator is responsible not only that these inspections have been signed off, but that the craft actually is airworthy. You might think it’s your mechanic’s responsibility, but if you own your craft, it’s your job.


Set the Record Straight

Vintage aircraft come to us with a past, and, as with many of us, it’s not always a proud one. Have you read all of your maintenance records? For an older aircraft that comes to you after several changes in ownership, it’s almost a given that there will be interesting details contained in these logs.

Commonly found in the attestation of an annual inspection is: “All ADs complied with.” That’s a sweeping statement that should offer you no comfort. ADs should be specified by number, compiled in a list stating how compliance was achieved and on what date, as well as show the next due date or time for recurring ADs. Even if you have such a master list, the maintenance entry for each annual or 100-hour inspection should specify which ADs were carried out at that inspection, and specify them by number.

With some of the logbooks I’ve read, “All ADs complied with” could be considered one of the three biggest lies in aviation. The other two being the one about the FAA being here to help you, and something I keep overhearing about a “mile-high club” (ahem).

My airplane’s logs had that type of entry, as well as some specific listings of ADs complied with, that on my first annual were proven to be untrue. For example, the recurring AD for inspection of the hollow crankshaft for corrosion pitting had been repeatedly signed off by the mechanic for the previous owner. However, when my mechanic had a look inside, he found a layer of thick grey mud, 3/8 inch thick, lining the crankshaft. This had not collected within the few hours I’d flown the airplane. The previous mechanic had obviously never looked at the crankshaft; he couldn’t have seen it through the gunk. Yet he’d signed off the AD — repeatedly.

You may have heard how difficult and expensive it is to import an airplane to Canada. Several discussions on ownership boards attest to this. But the import process is simply creating a new certificate of airworthiness in a new jurisdiction, for an old aircraft.

So, the process fully investigates all airworthiness issues that concern that craft and its accessories, examining the paper trail around them, and verifying the accuracy of these records. Why should that be time-consuming or costly if the airplane has been properly maintained and proper records have been kept? It shouldn’t be, yet I continually hear horror stories of the expense and time required to do an import. I help with the paperwork for my mechanic who does imports, and I am fascinated by what I’ve learned in doing this.

It’s surprising how many airworthiness issues crop up in almost every importation process. So think about this: If almost any importation process turns up airworthiness issues, it’s worth going through the exercise of examining airworthiness for any older craft or a craft for which you haven’t been the sole owner. Nearly every craft has a skeleton or two in its logbooks, and it’s well worth the time you’ll spend in tracking them down and setting them right. It is your responsibility.

The good news is that you can do this almost entirely yourself. Some weekend, when a cold front occludes a winter warm front and freezing rain moves in, build yourself a nice fire in the woodstove and settle in for several hours of maintenance log private investigation.

The first step is to read the logbooks. An older airplane with a lot of time on it, or several ownership changes, will have interesting entries; these will not put you to sleep. Keep a stack of sticky notes at hand to flag anything you want to check out further. You might find an old STC you had no idea was there, or an interesting repair detail that tells a story if you read between the lines.



Airworthiness Directives

Keep a notepad beside you to record AD numbers as you come across them, along with the date they’re mentioned. You can return to the entry for more details later if you need to, since you have noted the date. You’ll soon begin to recognize the recurring ones.

Next, check your maintenance records for the complete list of applicable

ADs; it should be in there somewhere, especially if you’ve had the airplane for a while and your mechanic is conscientious. If you can’t find it, you’ll need to create one. It’s not that hard. If you do find the list, it’s worth a run through the following steps anyway, just to be certain that nothing’s been missed. It’s what we do for an import.

You can find complete lists of ADs applicable to your airframe, engine(s), prop(s), and accessories (alternator, carb, mags, etc) online. It will help to be armed with the airplane’s equipment list, so you have the manufacturer of those accessories at hand. It will take a bit of work to determine which ADs apply to your particular craft, as the lists you’ll generate will include many that don’t. The Applicability section of the AD will tell you which model or serial numbers the AD applies to, or other specific details by which you can rule out that AD for your craft (cylinders overhauled by

Joe’s Engine Shop between 1995 and 1998, for example).

A few ADs have been superseded by revised versions. Note that, and note the new number when you find those.

Some ADs will refer to service bulletins that you will also need to look up to ensure you’re in compliance. Service bulletins are put out by the manufacturer (of the aircraft, engine, or accessory), and, although they’re called “mandatory service bulletins,” they’re not actually mandatory until or unless they become incorporated by reference into an AD.

Go through the AD list, one by one, to determine applicability. For those that apply to your craft, check compliance. This means both paperwork and actually having the work verified. You can check the paperwork. Where in the logs or in the AD list does it indicate the date the AD was complied with and the method of compliance? Date and method are the two facts that must be in your AD listing. How was it complied with? Did you replace a part, or complete an inspection? Is it a one-time thing, or does it recur? Inspections tend to be recurring, but, sometimes, otherwise- recurring ADs can be permanently complied with (PCW) by replacement of a part. At your next annual or other inspection, have your mechanic verify that the PCW items were, indeed, done.

For ADs on accessories, you may need to make a trip out to the airplane. Not every part on our airplanes gets its serial number recorded in the maintenance logs or updated on the equipment list when the part is changed, and its yellow tag may also have gone astray. Often, AD applicability hinges on a serial number or other specific configuration of the accessory. It may be necessary to go out with a mirror and a flashlight and read serial numbers off the part in order to finish this job.


Other Airworthiness Issues

A lesser-known requirement of FAR 91.403 is the manufacturer’s instructions for continued airworthiness.

These are also mandatory and usually apply to accessories or STCs to maintain the airworthiness of the specific item. Some mechanics are unaware of them, so an informed owner is essential on this one. Because they apply to STCs or accessories, they’re not covered in the original aircraft manufacturer’s technical data or inspection sheets. Therefore, they are specifically required in the FARs. Think of them as recurring ADs. For example, a specific shoulder harness STC requires periodic checks to the functioning of the inertial reel, usually done during the annual inspection.

Because of this and other issues, the next step in your forensic logbook examination is to make a complete list of the STCs that are referred to in the logs or that you find in the file. Then, check on them. Is all of the paperwork complete? Is there a Form 337 to match all of the STCs? Is the technical data there? Do the numbers match up? I once found a logbook entry for an STC with the wrong number; the STC number entered in the books applied to a different engine than the one in the aircraft. It took quite a bit of detective work to discover the correct number and obtain that STC for the craft, especially as it had been orphaned. The company listed on the FAA site as holding the STC had gone out of business, and I had to track down a new STC holder through the FSDO. Then, I had to find someone in that company to give me information. You can see how paying an importer to do this work could add up!

Is the technical data there for each STC? You need this for the STC paperwork to be complete, as it will contain the provisions for proper installation and any instructions for continued airworthiness.

If the technical data has gone missing, you will need to find replacement documents, usually obtained from the certificate owner.

Placards are another ownership issue. Are yours all there? Check. There is a list that’s required as part of the type certification, so it is an airworthiness issue. And, often, placards can go astray or severely deteriorate during the decades our airplanes have been flying, giving flight training, and sitting on the ramp in the sun. You will find the complete list of required placards in your pilot’s operating handbook (for a Piper) or in the type certificate data sheet (for a Cessna).

When you’re out at the airplane looking at placards, make a list of any equipment that’s inoperative. Has it been placarded as such? If there is any inoperative equipment aboard, be sure that it’s not required equipment. There’s a list of required equipment in FAR 91.205 for various types of flight (day, night, IFR). Anything that’s on those lists must be repaired or replaced before flight.

Of course, your compass card is probably installed, but it’s worth checking to see that it’s been revised to accommodate any changes to your avionics. What’s the date those numbers were last revised? Does it precede the last time a new radio or GPS was installed? If so, get it done again.

In the paperwork exercise, gather the weight and balance amendments and put them in order by date, if they aren’t already. Do you have a continuous sequence with no gaps? Is the most recent one the current one? Examine the logbook entries subsequent to the date of that most recent weight and balance amendment to ensure that no work has been done that would change the weight and balance, and that should be reflected in a new amendment sheet.

If you are considering redoing the paint and interior on your craft, it would be a good idea to have the airplane re-weighed at the same time. Older airplanes tend to gain weight, just like older people. It’s good to start from real data again after a few decades of paperwork amendments based on doing the math for items added or taken out.

After taking the time to go through the logbooks, the ADs, SBs, STCs, and placards, you’ll really know your craft. You’ll be certain it meets all airworthiness requirements. And, who knows, maybe someday you’ll want to sell it to a Canadian!