What was found
(CAN) ON APPROACH, THE ENGINE EXPERIENCED POWER LOSS, WITH ENGINE PERFORMANCE DETERIORATING THE ENGINE FAILED AND THE AIRCRAFT GLIDED TO A SAFE LANDING. POST-FLIGHT ENGINE COMPRESSION TEST REVEALED ALL FOUR CYLINDERS HAD LOW COMPRESSION. THE CYLINDERS AND PISTONS WERE REMOVED AND SENT FOR REPAIR. AFTER REPAIR, THE CYLINDERS WERE REPLACED. THE ENGINE WAS GROUND RUN SERVICEABLE AND THE AIRCRAFT RETURNED TO SERVICE.