As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED LOSING POWER IN CLIMB, CRUISE, AND DESCENT. FRICTION LOCK WORKS NORMAL AND NO THROTTLE MOVEMENT IS EVIDENT. ALL INDICATIONS SHOW LOSS OF POWER. ACCOMPLISHED ENGINE POWER RUN. ENGINE PARAMETERS NORMAL AND STEADY DURING TAKEOFF AND PART POWER SETTINGS. NO CAUSE FOUND FOR WRITE-UP. NO CORRECTIVE ACTION REQUIRED.