The AIM while guidance is not specifically regulatory and I wouldn't base a regulatory decision off it. Nothing has changed in the FAR's in regard to LPV/LDA, the wording in the AIM has changed but that isn't specifically legally binding (though it does further support the concept that only a ILS/MLS/PAR are precision approaches).
If you want specific language in the regulation itself, then look at 14 CFR 1.1, which defines a precision approach as a SIAP with an electronic glideslope:
Precision approach procedure means a standard instrument approach procedure in which an electronic glide slope is provided, such as ILS and PAR.
AIM 5-4-5 grants further clarification in it's latest edition by stating:
7. TERPS criteria are provided for the following types of instrument approach procedures:
(a) Precision Approach (PA). An instrument approach based on a navigation system that provides course and glidepath deviation information meeting the precision standards of ICAO Annex 10. For example, PAR, ILS, and GLS are precision approaches.
(b) Approach with Vertical Guidance (APV). An instrument approach based on a navigation system that is not required to meet the precision approach standards of ICAO Annex 10 but provides course and glidepath deviation information. For example, Baro-VNAV, LDA with glidepath, LNAV/VNAV and LPV are APV approaches.
(c) Nonprecision Approach (NPA). An instrument approach based on a navigation system which provides course deviation information, but no glidepath deviation information. For example, VOR, NDB and LNAV. As noted in subparagraph i, Vertical Descent Angle (VDA) on Nonprecision Approaches, some approach procedures may provide a Vertical Descent Angle as an aid in flying a stabilized approach, without requiring its use in order to fly the procedure. This does not make the approach an APV procedure, since it must still be flown to an MDA and has not been evaluated with a glidepath.
The difference between former definitions and the present? The inclusion of compliance with ICAO standards for Annex 10.
What is cited in one's operation specifications does not define the regulalation, neither does any particular SIAP standard instrument approach procedure define the regulation. The SIAP is appended to Part 97 of title 14 of the Code of Federal Regulations, making compliance with the procedure when having accepted a clearance for that procedure, mandatory. However, the procedure does not define the regulation. Compliance therewith is enforced by the regulation, specifically 14 CFR 91.123. The SIAP itself is not binding upon an airman or operator until a clearance for that procedure has been received and accepted. Accordingly, while one may say the procedure is "regulatory" as it is appended in it's current form to Part 97, it doesn't define the regulation nor does it set or establish regulation. The procedure itself is defined by regulation, and one cannot look to a given procedure, in this case, to help define what is or is not a precision approach. We have other specific guidance to tell us that.
The clearing house of information in this regard, the AIM, is very specific on the matter as to not only the definition, but the reason behind it. The AIM is not a regulation, but a summary of regulation, policy, and procedure. Further, contrary to the belief of many, you will be held accountable for adherence to what's contained therein. Much of it is verbatim from the regulation, and it's intended as a clear, concise summary that brings all the necessary information into one place as a reference. You really don't have the option of dismissing or ignoring it. It's accurate and correct, and provides important clarification on many operational issues and procedures. Title 14 of the CFR (the "FAR's") was designed with this purpose in mind. The regulation provides the framework, or the skeleton, if you will, and the additional documentation (Federal Register Preambles, FAA Chief Counsel Legal Interpretations, and other documents and summation, to include the AIM) forms the flesh.
Again, the information has already been covered and provided in enough scope and detail that as stated before, no further response should be necessary. All the "I think it should mean" or "it ought to say" in the world doesn't change what's provided, and what's provided is clear enough.
