Although I’ve never been involved in rulemaking, I can understand why it is a thorn in the side for a regulatory agency. Recently proposed changes for use of simulator time towards an instrument rating make a perfect example.
Since the 1980’s, the amount of time an applicant could use in an aviation training device (ATD, although that is not what they were called at the time) towards an instrument rating was included in the letter of authorization (LOA) approving the device. This was based on guidance in advisory circulars.
