Since the cited AD sez:
The service information referenced in this AD may be obtained from Teledyne Continental Motors, P.O. Box 90, Mobile, AL 36601; telephone (334) 438-3411.
with no reference to R-R, I'd say they're referring to one engine -- is a Packard Merlin not a Rolls-Royce Merlin?
J. Beach Brennan WST
