As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - FLIGHT CREW NOTICED ACRID BURNING ODOR IN COCKPIT, NO SMOKE NOTED. ODOR IS STILL NOTICEABLE AFTER PARKING. FOUND CAPTAINS HAT WAS HUNG ON OBSERVERS MAP LIGHT THAT WAS ON. MELTING CAPTAINS HAT CAUSING ACRID ODOR IN COCKPIT. NO OTHER DEFECTS NOTED. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.