Is RVSM authorization granted through the issuance of OpSpec or an Letter of Authorization (LOA)?
Per Advisory Circular (AC) 91-85 if you are a part 91 operator or a part 125 operator holding a letter of deviation authority (LODA), you will simply be issued an RVSM LOA after the RVSM authorization process has been successfully completed. Part 121, 125, 129, and 135 operators will be granted approval to operate in RVSM airspace through the issuance of OpSpec paragraph from Part B (En Route Authorizations, Limitations, and Procedures) and Part D (Aircraft Maintenance). Each aircraft type group for which the operator is granted authority should be listed in OpSpecs. Additionally Part 91K operators’ authorization to operate in RVSM airspace should be granted through the issuance of a management specifications (MSpecs).
Part 91 operators are not required to obtain a new or amended LOA to operate in individual areas of operation where RVSM is implemented. For example, an operator that has obtained an LOA and is conducting RVSM operations in the North Atlantic is not required to obtain another LOA to conduct RVSM operations in the domestic United States.