As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THROUGH FL 210, CREW ENCOUNTERED AN STRONG ODOR. ODOR SEEMED TO CYCLE -A 2-3 MINUTE CYCLE -IN INTENSITY. SEEMED TO BE ISOLATED TO COCKPIT. ODOR LESSENED DESCENDING THRU FL180, BUT DID REMAIN NOTICEABLE THROUGHTOUT THE LANDING AND SHUTDOWN. R & R COCKPIT RECIRCULATING FAN ASSY. OP'S CK. GOOD INSTALLED ACCESS PANELS IAW MM 21-22-00.