NTSB Identification: CHI01LA318.
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Accident occurred Wednesday, September 19, 2001 in St. Bonifacius, MN
Probable Cause Approval Date: 06/04/2002
Aircraft: Cirrus Design Corp. SR-20, registration: N747TW
Injuries: 2 Serious.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The pilot said that 3-5 minutes after leveling off at 3,000 feet, a red oil light appeared on the instrument panel. The pilot said he looked over at the oil pressure gauge. It read zero pressure. The pilot said that the engine started missing. He contacted departure control and informed them he had an emergency with no oil pressure. The pilot said, "Departure asked if I wanted [the] ILS for Flying Cloud [Airport], which was 12-13 mile[s] away." The pilot said it was too far and decided to go for Waconia. The pilot said he set up for best glide airspeed and informed departure that he was still in the weather. The pilot said that at 2,000 feet, he noticed smoke begin to appear from the cowling. The pilot said he broke out of the clouds approximately 800 feet agl. The pilot said he set the airplane down in a cornfield, slid approximately 70 feet, and came to a stop. An examination of the airplane's engine revealed 3 punctures in the top of the crankcase at cylinder numbers 1, 2, and 4. A 2-inch diameter piece of the crankcase rested on top of the engine. The oil drain plug was absent. The threads at the oil drain port showed no damage or evidence of safety wiring. The oil dip stick and oil filter showed heat damage. A film of oil was observed on the firewall. There was no evidence of oil in the engine. No other anomalies were found. A mechanic for the airplane's owner said that he started an oil change on the airplane a week before the accident. The mechanic said that while performing the oil change he noticed damage to the airplane's nose gear. The mechanic said he abandoned the oil change. He said at that time he didn't have safety wire or a new crush washer for the drain plug. He left the airplane in that condition. He said it was the last time he saw the airplane. A second mechanic said that the day before the accident he and his partner repaired the nose gear and completed the work on the airplane. The mechanic said, "I vividly remember checking the safety on the oil filter. I cannot remember the condition of the oil drain plug. We cowled the powerplant and conducted a leak check." The mechanic said that the pilot ran the engine for approximately 1 minute. It was then inspected for leaks. No leaks were found. The POH narrative for Forced Landings states, "For forced landings on unprepared surfaces, use full flaps if possible." No reference to flap position is cited in the checklist steps. The flaps were up at the accident site.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: Improper servicing of the airplane by other maintenance personnel, inadequate inspection of the airplane by the other maintenance personnel prior to the airplane's flight, and the unsuitable terrain encountered during the forced landing. Factors relating to the accident were the oil exhaustion, the low ceiling providing the pilot little time to select a field once the airplane was beneath the clouds, the pilot not following proper emergency procedures requiring use of full flaps for the forced landing, and the corn crop. Full narrative available
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