NTSB Identification: CHI99LA308.
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Accident occurred Saturday, August 21, 1999 in GRANITE CITY, IL
Probable Cause Approval Date: 01/18/2001
Aircraft: Piper PA-18-150, registration: N90904
Injuries: 2 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.

The pilot said that during cruise flight the engine lost power. During the forced landing on rough and uneven terrain the airplane was substantially damaged. The pilot said he did not know the nature or origin of the loss of engine power. Subsequent to the accident, but after the airplane was moved to a location away from the accident site, an inspection of the engine and airframe failed to reveal any mechanical anomalies. The top spark plugs were removed and had brown deposits on them. The wings had been removed and no fuel remained in the fuel tanks; however, what fuel was present in the lines appeared blue in color, and was free of contamination.

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

Loss of power for undetermined reason(s) and the rough/uneven.

Full narrative available

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