As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FL 410 IN CRUISE, EXPERIENCED A BURNING SMELL IN THE COCKPIT. PASSENGERS ALSO CONFIRMED THE SMELL IN CABIN. LANDED ASAP AND DID NOT HAVE TIME TO TROUBLESHOOT ENVIRONMENT CHECKLIST. SMELL WENT AWAY AFTER ENGINE SHUT DOWN. REMOVED AND REPLACED COCKPIT ACM. OPS AND LEAK CHECK GOOD REF CESSNA 750 MM CH 21-51-00.