What was found
(CAN) CUSTOMER REPORTED THAT DURING CLIMB WET-SOCKS SMELL IN COCKPIT. THE PILOT ELECTED TO RETURN BACK TO THE AIRPORT AND LANDED. ALTHOUGH OXYGEN MASKS WERE USED, THERE IS NO REPORT OF CREW OR ANY PERSONNEL REQUIRING MEDICAL ATTENTION. AFTER TROUBLESHOOTING, IT WAS DECIDED TO REPLACE THE ENGINE. PRATT AND WHITNEY WILL INVESTIGATE TO ESTABLISH ROOT CAUSE AND PROVIDE INFORMATION TO TRANSPORT CANADA THROUGH SUBSEQUENT SERVICE DIFFICULTY REVIEW MEETING AND SUPPORTING DOCUMENTS OR OTHER AGREED UPON COMMUNICATIONS. (TC# 20190524002)