The FAA generates ADs through the (usually) normal rulemaking process. Essentially, something comes up: a failure, service reports from mechanics, the need for the manufacturer to get some additional profit, that brings it to the FAA Attention.Thanks. If I could ask a follow up, who is it that generates AD's?
Most seem to be done by model and serial number in my experience. Note, it's not as simple as "A 1978 Cessna 172" to lookup. Each part on the plane can potentially have an AD on it. You have to look at anything issued that MIGHT apply. There was, for example, an AD on a certain set of serial numbers on a certain fuel pump that might have been installed on an engine that might be on my plane.I am trying to figure out from the posts here. It seems these are per aircraft model (and I'm guessing may even be a range of manufactured years? Like a Cessna 172 SP made between 1962-1973 etc.?)
The source is varied. Used to be manufacturers were proud to NOT have ADs but between liability concerns and the fact that some ADs are profit makers, this has changed.but as an example would it be generated by Cessna to address a problem, then vetted by FAA and at that point FAA generates an AD? Or do the manufacturers create them and the FAA just maintain the list of (suggested, or mandated?) AD's?
There is a database of ADs: https://www.faa.gov/regulations_policies/airworthiness_directives/
But as I described above, it's not just the matter than you can type your N-number in and get a list of all that might apply.