NTSB Identification: CHI97LA142.
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Accident occurred Tuesday, May 20, 1997 in WHEELING, IL
Probable Cause Approval Date: 06/09/1999
Aircraft: Mooney M20F, registration: N6950V
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On the first flight after maintenance, the pilot reported that on the initial climb, 'the engine stopped producing power and began behaving erratically.' The pilot declared an emergency to the controlling ATC personnel, and turned back to Palwaukee Municipal Airport. The pilot reported that the engine, 'was backfiring and sounded like only one cylinder was hitting.' The pilot selected a field to execute a forced landing, circled it twice, and landed on an easterly heading. The pilot reported that the plane, after touch down, 'skidded and rolled for about 250 yards before coming to rest on the bank of a small creek.' The pilot evacuated the airplane and waited for assistance. Examination of the number four cylinder revealed excessive black carbon build-up on the cylinder head and exhaust valve seat.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

binding of the number four exhaust valve, which resulted in a partial power loss. A factor was the ravine.

Full narrative available

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