Alternate static source
I'm new to Sikorsky S-76D and wondering why alternate air source is not equipped with S76D?
As far as I know the regulations in FAA is as below
AC 29 APPENDIX B. AIRWORTHINESS GUIDANCE FOR ROTORCRAFT INSTRUMENT FLIGHT
(9)IMC Evaluation.
(B) An alternate static source with a means of selecting this source must be provided for single pilot configurations.