Installation of second pilot s seat and dual controls or passenger/cargo compartment in accordance with Serv-Aero Engineering, Inc. FAA sealed Master Drawing List MDL 012880 "A", dated April 21, 1980, or later FAA approved revision. P&W R-1340-AN-1 engine is required with this installation. FAA Approved Serv-Aero Airplane Flight Manual Nermission. Supplemental Type Certificate Addendum No. SA4112WE is a part of this STC. (S2R s/n 2526R and up modified by STC SA3961WE) View PDF on drs.faa.gov ↗

The STC PDF is authoritative: installation instructions, ICA requirements and limitations.