19980926026649A

Acft laned hard due to engine failure and severed the right main landing gear.(.19) on September 26, 1998, at 1200 hours pacific daylight time, a rockwell commander 114, N114AL, landed hard and severed the right main landing gear after experiencing an engine failure at the Castle air force base in merced, California. The aircraft sustained substantial damage and the private pilot, the sole occupant, was not injured. The personal flight originated at the watsonville, California, airport at an unspecified time and no flight plan was filed. Visual meteorological conditions prevailed. The pilot reported that the engine sputtered then quit as he was turning base for runway 31, approximately 400 to 700 feet AGL and about 1/2 mile out. He notified the tower that he was experiencing engine problems and continued toward the runway to land. The pilot reported that he landed hard and the right main landing gear sheared off. The aircraft continued forward on the runway approximately 1,200 feet, then impacted a runway light and veered off into a grassy area. A federal aviation administration inspector from fresno, California, flight standards district office responded to the accident site and reported that the fuel tanks were approximately 3/4 full. He further stated that he reviewed the aircraft maintenance records and noted that the right magneto had received maintenance work the day prior to the accident. (From .4) the engine sputtered then quit as the pilot was initiating a turn to base. He landed hard on the runway and severed the right main landing gear. The aircraft continued forward on the runway, then impacted a runway light and veered off into a grassy area. An FAA inspector examined the engine and noted no external damage. The aircraft was equipped with a dual cased single-drive magneto and the maintenance records indicated that a 500-hour inspection had been performed on the magneto on June 13, 1998. The mechanic reported that he checked all the points for evidence of arcing and found none. He stated that he ran the magneto on a test bench and it ran normally. Postaccident examination of the magneto on a test bench and it ran normally. Postaccident examination of the magneto revealed that the right points did not open and the left points would close intermittently. It was further noted that the cam followers for both sides of the magneto were melte d. neither capacitor passed the insulation resistance test at 400 vdc. The magneto was test run with the original harness and capacitors attached. Both sides of the magneto generated sparks at 500 and 1,000 RPM. A 150-watt lamp was set up next to the magneto to simulate engine heat. The magneto was then run at a speed approximating cruise speed. After 5 minutes, the right magneto ceased to generate sparks. The left magneto generated sparks for the duration of the test. The pilot reported that he performed two magneto checks prior to takeoff, with no noted discrepancies. (-23) the aircraft departed watsonville muni (wvi) and was inbound to the Castle airport (mer) and was told to go to the northwest aircraft traffic area which is the five mile radius course to enter right traffic for arrival to runway 31. Upon turning to final approach, the pilot stated that he had moved the fuel selector from the "left" position to the "both" position in accomplishing the final checks prior to landing. This procedure encompasses checking the landing gear, fuel, mixture, propeller setting and seat belt security. As he approached the runway at approximately 1/2 mile away and 40 0 to 700 feet AGL, the engine began to sputter and it quit. He said he was lined up with the centerline and notified the tower of this problem as he continued to land. The aircraft first contacted the runway in between the threshold marker and the 500 foot marker and just right of the centerline. The impact was hard enough to sever the right main landing gear and outboard gear door. The aircraft bounced and continued airborne until contacting the runway a second time.