Burden of proof

Data plates are the legal foundation of the airplane and engine. The regulations require manufacturers affix them to the airframe and engine, and mechanics are required to verify their presence during the annual inspection. Owners of experimental aircraft may have more leeway, but those of us flying certificated aircraft must have them.

Curiously, when I called a few mechanics during the purchase process, I was told it’s a common problem with antique aircraft, and not to worry too much about it. So, I didn’t. My ability to don’t worry, be happy only lasted a few months, as my concern of whether my chosen mechanic would sign off the annual without it took over. Then I began the process to replace the Continental A-75’s data plate.

The process for ordering a replacement is clearly spelled out in advisory circular 45-3A. In short, an inspector from your flight standards district office must write a letter authorizing the replacement, which you then send to the manufacturer (Continental in my case), which will then make the plate and send it to you. The regulations are clear that even though the letter from the FSDO enables the plate to be made, only the manufacturer can make it. Occasionally you’ll see businesses online offering data plate replacement as a service, but strictly speaking, this isn’t legal. It is legal to buy a blank plate and have the manufacturer stamp it, but that’s only done if you want a particular style.

Like all things with the FAA, your experience through the first step of this process will vary. You may read stories of inspectors asking only to see photocopies of the engine logbook, at which point the letter will quickly arrive. I did not have this experience.

The inspector I worked with at my FSDO first had to get back to me after researching the process. He then asked to come and inspect the airplane personally. On the day of the meeting multiple inspectors showed up, apparently because it represented a training opportunity. I was effectively asking for a ramp check. On a cold winter morning we all huddled around my engine on the ramp and the inspector began by saying, “OK, show me what proves the engine matches the logbooks.” In other words, I had the burden of proof. He wasn’t going to seek out his own evidence.

I pointed to detailed logbook records, photos, repair tags, receipts, and serial numbers on accessories that matched, and more. He suggested that accessories are bolt-on attachments, and didn’t serve as proof that the logbook and engine matched.

For a few months I tried everything I could think of to convince the inspector, including photos from a previous owner that showed the data tag on the engine with some case stampings that matched.

Finally, I got lucky when I mentioned that my Cub had been inspected by a designated airworthiness representative two years prior as part of the process of getting the airplane back into the normal category after a few decades of being experimental. The FAA inspector said if I could get the DAR to verify it was the same engine he had inspected (when the data plate was still on) that he would issue the letter. One very long flight and a three-minute inspection later and I had the verification, and the FAA letter soon after.

The airplane then went into annual, and I was excited to soon spend my first fall flying above the changing leaves at 500 feet with the door open. Continental had other plans. Despite desperate pleading and maybe some begging and groveling, it took four months to receive the new data plate. In addition to getting verification from the FAA, the manufacturer also verifies through its records that the engine is what you say it is. Continental’s records on engines that go back to the Eisenhower era apparently aren’t complete, and although the actual stamping only took a few days to get through the production team, verifying the information took far longer.

The moral of the story is not to buy an airplane or an engine without a data plate unless you like to gamble, have a special friend at the FAA, or don’t mind ending up with an unairworthy airplane or engine.

Data plates can and do fall off. When that happens, you are left with few options other than the process outlined in the AC. Especially on older engines, bankruptcy isn’t the only option. Cases with data plates are relatively inexpensive, and even fully built-up mid-time engines are cheap enough to keep the airplane from being scrapped. It certainly won’t hurt anything to take detailed photos and document as much as you can, but whether or not your FAA inspector will accept that documentation if the data plate ever decides to depart the airplane is an open question. The most proactive thing you can do is not ignore missing or lose mounting hardware. Because if the data plate goes flying, you won’t be.