# Being an aircraft mechanic is hard (on paper)

_September 30, 2026 · https://journey.easyfaa.com/entries/1_

Every aircraft needs an annual inspection. Mechanics spend hours with the hassle of figuring out whether any [FAA Airworthiness Directive](https://drs.faa.gov/browse) applies to that aircraft. Comparing ADs with [aircraft data](https://registry.faa.gov/aircraftinquiry) is cumbersome and prone to errors.

Here are the top ten traps to look out for:

## 1. A dozen spellings for one engine

An AD says [O-200-A](https://easyfaa.com/E/Cont-Motor-O-200A), but the registry says “[0-200 SERIES](https://easyfaa.com/E/Cont-Motor-0-200-Series)”, with a zero, not the letter O.

More than 8,000 registered aircraft have an engine written with a zero.

## 2. “Series” means two different things

In an AD, “737-800 series” means the [737-823](https://easyfaa.com/M/Boeing-737-823) and the [737-8H4](https://easyfaa.com/M/Boeing-737-8H4). In the registry, “[O-200 SERIES](https://easyfaa.com/E/Cont-Motor-0-200-Series)” means “we don’t know which variant”.

More than 180,000 registered aircraft have a model or engine named only by its family.

## 3. Most ADs hang on something the registry doesn’t know

Think of “[equipped with P/N 0322709](https://easyfaa.com/AD/2004-21-08)”, “[modified per STC SA64CH](https://easyfaa.com/AD/2008-22-18)”, “[with 25 or more hours](https://easyfaa.com/AD/1981-23-03)”.

Almost 10,000 ADs in force have a condition like this.

## 4. “As listed in Service Bulletin…”

More than 4,000 ADs don’t say which aircraft they cover.

They point to a [service bulletin](https://easyfaa.com/AD/2005-22-10) you then have to find and read.

## 5. The AD may have been rewritten

653 ADs in force are really [a later revision](https://easyfaa.com/AD/2009-10-09), and 13 revisions don’t revise at all: they [rescind the AD](https://easyfaa.com/AD/1995-26-05) entirely.

Read the original and you’re reading the wrong rule.

## 6. Parts ADs are invisible

[Magnetos](https://easyfaa.com/A/4251), [carburetors](https://easyfaa.com/A/MA-3SPA), [oil filter adapters](https://easyfaa.com/AD/1996-12-22), [avionics](https://easyfaa.com/AD/2006-16-18): the registry never records what’s installed.

426 ADs are about parts that could be on your airplane, or not.

## 7. Slashes are shorthand

“[207A/T207A](https://easyfaa.com/AD/2000-06-01)” means two models. “[L/TSIO-520](https://easyfaa.com/AD/1991-19-03)” means the TSIO-520 and the LTSIO-520.

About 300 ADs write models this way.

## 8. Serial numbers aren’t always serial numbers

“[Line numbers 1 through 500](https://easyfaa.com/AD/1997-20-01)” are Boeing line numbers, not the serial on the data plate.

“[Except S/N 1](https://easyfaa.com/AD/1977-13-21)” means every serial but one. “[27-1 and up](https://easyfaa.com/AD/1983-22-01)” has no end.

## 9. The index is broader than the AD

The FAA [files each AD](https://drs.faa.gov/browse) under the makes and models it might touch.

You must read them to see if your aircraft is ruled out by serial number.

## 10. Superseded ADs don’t disappear

More than 2,000 ADs in force [replace older ones](https://easyfaa.com/AD/2004-19-01).

The old ones still show up in logbook entries, and still need to be tracked.