NTSB Identification: LAX89LA151.
The docket is stored on NTSB microfiche number 40122.
Accident occurred Saturday, April 08, 1989 in PRESCOTT, AZ
Probable Cause Approval Date: 08/02/1990
Aircraft: MOONEY M20F, registration: N9705M
Injuries: 4 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 AIRPORT ELEVATION WAS 5,042 FEET, AND THE DENSITY ALTITUDE WAS 7,600 FEET. THE FLIGHT INSTRUCTOR STATED THEY HAD ABORTED THE FIRST TAKEOFF ATTEMPT BECAUSE THE ENGINE RPM WAS INSUFFICIENT FOR TAKEOFF. ON THE NEXT ATTEMPT, THE AIRPLANE BECAME AIRBORNE AND FLEW IN GROUND EFFECT. THE ENGINE RPM WAS INSUFFICIENT TO SUSTAIN FLIGHT. THE FLIGHT INSTRUCTOR TOOK CONTROL AND BANKED THE AIRPLANE TO AVOID POWERLINES. THE AIRPLANE DESCENDED INTO AN OPEN FIELD. THE CFI DID NOT LEAN THE MIXTURE FOR TAKEOFF. HE SAID HE BELIEVED THE CARBURETOR HAD AN AUTO-LEAN FEATURE AND HE DID NOT HAVE TO LEAN THE MIXTURE. THE IO-360 ENGINE IS FUEL INJECTED AND DOES NOT HAVE AUTO-LEAN. POST ACCIDENT ENGINE RUN REVEALED THE ENGINE WAS CAPABLE OF NORMAL OPERATION WITH FUEL MIXTURE PROPERLY SET.

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

THE FAILURE OF THE PLT TO LEAN THE FUEL MIXTURE FOR THE HIGH DENSITY ALTITUDE. CONTRIBUTING TO THE ACCIDENT WAS THE CFI'S LACK OF FAMILIARITY WITH THE AIRPLANE AND ENGINE OPERATING PROCEDURES.

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