NTSB Identification: CHI94LA224.
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Accident occurred Friday, July 08, 1994 in ANDOVER, MN
Probable Cause Approval Date: 02/24/1995
Aircraft: CESSNA 150, registration: N9284U
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 FLIGHT INSTRUCTOR AND PRIVATE PILOT WERE PRACTICING EMERGENCY PROCEDURES WHILE ON A BIENNIAL FLIGHT REVIEW. THE INSTRUCTOR REPORTED THAT HE INITIALLY REDUCED THE THROTTLE TO SIMULATE A ROUGH ENGINE, AND THEN PULLED THE MIXTURE OUT (TO THE 'OFF' POSITION)TO SIMULATE AN ENGINE FAILURE. THE PRIVATE PILOT SUBSEQUENTLY PULLED CARBURETOR HEAT TO 'ON' AND PERFORMED OTHER EMERGENCY PROCEDURES. THE INSTRUCTOR WAS SATISFIED WITH THE PILOT'S RESPONSE, AND TOLD HIM TO RESTORE THE ENGINE POWER. THE ENGINE DID NOT REGAIN POWER WHEN THE MIXTURE WAS PUSHED IN. THE INSTRUCTOR MADE AN EMERGENCY LANDING ON A NEARBY LAWN/FIELD, STRIKING OBSTRUCTIONS DURING THE LANDING ROLL. THE REPORTED TEMPERATURE IN THE AREA AT THE TIME OF THE ACCIDENT WAS 61 DEGREES AND THE DEW POINT WAS 59 DEGREES. THESE TEMPERATURES FALL WITHIN THE SEVERE ICING RANGE ON A CARBURETOR PROBABILITY CHART. THE AIRPLANE'S ENGINE WAS STARTED AND RUN AT THE ACCIDENT SITE WITHOUT ANY OBSERVED MECHANICAL DEFICIENCIES.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the flight instructor's improper procedures and directives by electing to pull the mixture control to the 'off' position during simulated emergency procedures. A factor associated with the accident is the existence of weather conditions conducive to carburetor icing. Full narrative available
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