CORONA, CA, USA
N250P
CASSUTT III M
THE AIRPLANE EXPERIENCED A LOSS OF ENGINE POWER ON TAKEOFF. THE PILOT EXECUTED A 180 DEGREE TURN AND LANDED ADJACENT TO THE DEPARTURE RUNWAY. THE ENGINE EXAMINATION DISCLOSED ONE MAGNETO WAS INOPERABLE. THE ENGINE VALVE SPRINGS WERE FROM A DIFFERENT MODEL ENGINE.
On May 7, 1993, at 1544 hours Pacific daylight time, a Cassutt III M, N250P, lost control and collided with level terrain after takeoff from the Corona Municipal Airport, Corona, California. The pilot was conducting a local visual flight rules personal flight. The airplane was destroyed. The certificated commercial pilot received serious injuries. Visual meteorological conditions prevailed at the time. The accident was witnessed by a FAA Accident Prevention Counselor (APC). According to the APC the airplane was observed turning when it appeared to stall. The airplane descended until colliding with the ground. Friends of the pilot indicated that the pilot complained of chest pains days before the accident. According to the FAA, the pilot's doctor indicated that the pilot had suffered recent heart damage. On September 2, 1993, Safety Board investigators examined the engine at Corona Airport, Corona, California. The following are the results of the examination: EXTERNAL EXAMINATION The engine was removed from the aircraft before the examination by an unknown party and the following had been removed: the propeller, magnetos, exhaust system and parts of the fuel and electrical systems. There was no evidence of impact damage to the engine casing and there was no data plate on the engine. The valve covers and carburetor had been removed and reinstalled prior to the examination by an unknown party. Spark Plugs Six of the spark plugs were AC plugs; four of which were S-88 and the remaining two were unknown. The other two spark plugs were Champion M41E and were installed in the top position of cylinders number one and two. All spark plug electrodes showed signs of normal erosion with the center ground electrodes being about half of their original thickness. Also, wet, oily deposits were noted on the spark plugs. Valve Covers Continuity of the gear and valve train assembly was established. Compression was evident during the continuity crankshaft rotation and there was no visual sign of valve leakage. The valve covers exhibited evidence of circular marks created by the valve rocker shafts. ACCESSORIES Magnetos Two Bendix S4LN-21 magnetos, serial numbers 587045 and 562364, were given to the investigator by a friend of the pilot who said that these magnetos had come off of the engine. The magnetos engine position could not be determined due to the absence of their respective wiring harnesses. Magneto, serial number 587045, produced spark upon rotation of its drive shaft; the remaining magneto did not produce spark. DISASSEMBLY Cylinders The chrome cylinders contained a small amount of oil that was light brown in color and water contamination was noted. Safety Board investigators did not determine the origin of the contaminates. Camshaft and Valve Springs The pilot's friend reported that Continental O-200 camshaft and valve springs were installed on the engine. A representative of Teledyne Continental said that replacement of the original camshaft and valve springs by the O-200 series would not adversely effect the engine operation. However, the O-200 camshaft and valve springs are not approved by the manufacture for installation in the C-85 engine. Valve Seats The intake valve seats exhibited evidence of carbon deposits. Pistons The pistons exhibited evidence of triangular patterned carbon deposits directly opposite of the bottom plugs.
the pilot improper maintenance modification and total failure of the magneto.
Source: NTSB Aviation Accident Database
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