The Halifax Class frigates are in the process of a mid-life modernization. The engineeringchanges made to the ships during the refit have resulted in significant superstructure modificationsaffecting both the airwake over the flight deck and the accuracy of the mast-mountedanemometer system. This requires that the CH124 Sea King Ship-Helicopter Operational LimitsSHOL envelope be re-certified for operation from post-refit ships. This re-certification will involveextensive wind tunnel experiments conducted by the National Research Council NRC inaddition to a limited sea trial program. This report summarizes DRDCs contribution to the seatrial conducted on HMCS FREDERICTON in December 2013 that was part of this effort. Theship was instrumented with supplementary anemometers at the bow and mast to help validatethe wind tunnel experiments. Aircraft operations were conducted by Aerospace Engineering TestEstablishment AETE as part of the SHOL development with support from the prototype FlightDeck Motion System FDMS developed by DRDC Atlantic. Analysis and interpretation of theresulting data set is presented in separate reports by AETE and NRC.