As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING COMPLIANCE OF LYCOMING SI 1427B, 'GROUND TEST PROCEDURES', ENGINE STOPPED RUNNING DURING 3 TO 5 SECONDS OF 'FULL STATIC POWER CHECK'. ALL ENGINE OPERATING PARAMETERS WERE NORMAL BEFORE FAILURE. PROPELLER COULD NOT BE MOVED BY HAND AFTER FAILURE. PROPELLER AND ALL ACCESSORIES WERE REMOVED AND INSPECTED. NO DEFECTS IN ACCESSORIES OR PROP WERE FOUND.