As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DESCENDING THROUGH ABOUT 10,000' BOTH PILOTS FELT A ENGINE SURGE. NOTICED THE LEFT ENGINE PROP RPM FLUCTUATING. STABILIZED @ 850 RPM. NO PROBLEMS AFTER LANDED IN 850 RPM. REMOVED FROM SERVICE. CHECKED CDS. FOUND FAULT 260 A ON #1 PROP POSTED ON 27 JAN 2022, 16:06:19. C/W FIM TASK 61-20-06-810-818. REPLACED #1 PEC IAW Q400 AMM TASKS 61-20-36-000-801/400-801. ALL CALIBRATION & OPS TEST GOOD. NO FAULT CODES RETURNED. RETURNED TO SERVICE.