and they weren't dealing with part 121 at the time.
They were dealing with Part 121 back in 2004. When you hear us talking about a new certification...what we are talking about is a revised certification. It was designed to strengthen the certification process after extensive studies from the NTSB recommendations. The studies found a lot of weak points and submitted them to the FAA. Then in turn, the FAA rewrote a lot of things including the security measures that were recommended after 9/11.
When the FAA created AC 43-208, it was choking the process as well as setting up the FAA to shoot themselves in the foot. This was written in 2003, and again revised last month because of what Baltia's mini test has discovered.
Part 121 is a classification of what the airline plans to serve the capacity in. Part 121 is in short "Operating Requirements: Domestic, Flag, and Supplemental Operations"
These codes has been around since 1958. If you want to know more about the FAA codes, refer to here: