As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PULLING THE POWER BACK FOR DESCENT, GOT A STRONG SMELL. COCKPIT ACM BECAME HARD TO CONTROL. FOUND COCKPIT ACM TO HAVE FAILED. REMOVED ACM AND INSTALLED OVERHAULED UNIT. OPERATIONAL AND LEAK CHECKS GOOD. WORK DONE IAW CHAPTER 21-51-00 OF THE CITATION 750 MM.