As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE PERFORMING A SCHEDULED INSPECTION, THE PILOT STATED THE VACUUM FLUCTUATED. FURTHER INSPECTION REVEALED THE SPLINES ON THE VACUUM PUMP HAD FAILED. THE VACUUM PUMP WAS REPLACED WITH A NEW PUMP,AND FUNCTION CHECK WAS CARRIED OUT SATISFACTORY. ALL WORK WAS PERFORMED IAW THE APPLICABLE MAINTENANCE PUBLICATIONS. NOTE: VACUUM PUMP TSO STATED IS AN ESTIMATED TIME ONLY. (TC# 20190730027)