NTSB Identification: CHI89LA141.
The docket is stored on NTSB microfiche number 39368.
Accident occurred Saturday, July 22, 1989 in WISCONSIN DELLS, WI
Probable Cause Approval Date: 07/09/1990
Aircraft: CESSNA R172K, registration: N736DA
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.

WHILE EN ROUTE, THE PLT HEARD A 'MUFFLED POP' FROM THE ENG. APRX 30 SEC LATER, HE NOTICED SMOKE ENTERING THE COCKPIT & SOME POWER LOSS. OIL PRESSURE WAS OBSERVED GOING TO ZERO. THE PLT SHUT OFF THE FUEL & MADE AN EMERG LANDING. DRG THE LANDING, THE LEFT WING STRUCK A TREE & THE ACFT WAS DAMAGED. A POST-ACDNT INSPN REVEALED THE OIL FILLER CAP WAS LOOSE & HANGING FROM ITS CHAIN. A TEARDOWN INSPN OF THE ENG REVEALED NO EVIDENCE OF MECHANICAL DEFECTS WHICH WOULD HAVE ACCOUNTED FOR THE OIL LOSS.

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

FAILURE OF THE PILOT TO INSURE THE OIL FILLER CAP WAS PROPERLY SECURED WHEN HE SERVICED THE AIRCRAFT BEFORE TAKEOFF, AND SUBSEQUENT LOSS OF OIL AND OIL EXHAUSTION. THE TREE WAS CONSIDERED TO BE A CONTRIBUTING FACTOR.

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