NTSB Identification: CHI88DER03.
The docket is stored on NTSB microfiche number 37934.
Accident occurred Thursday, June 16, 1988 in MORA, MN
Probable Cause Approval Date: 11/28/1989
Aircraft: CESSNA 172K, registration: N7499G
Injuries: 4 Uninjured.

DRG FLT, ONE OF THE PLTS DEMONSTRATED A NEGATIVE 'G' MANEUVER BY ENTERING A CLIMB, THEN MAKING A 'PUSH OVER' TO A DESCENT. HE THROTTLED BACK ON THE BACK SIDE OF THE MANEUVER TO MAINTAIN AIRSPEED. WHEN THE THROTTLE WAS READVANCED, THERE WAS NO ENG RESPONSE. EMERGENCY PROCEDURES WERE INITIATED, BUT THE ENG WOULD NOT RESTART. SUBSEQUENTLY, A NIGHT LANDING WAS MADE IN A WOODED AREA & THE ACFT WAS EXTENSIVELY DAMAGED. LITTLE FUEL WAS FOUND REMAINING IN THE ACFT, BUT FUEL HAD DRAINED FROM THE FUEL SYSTEM AFTER THE ACDNT. DURING A CHECK OF THE MAGNETOS, ONE PROVIDED NO SPARK & THE OTHER PROVIDED ONLY A WEAK SPARK. THE MAGNETOS WERE DISASSEMBLED; BOTH WERE FOUND TO HAVE LOOSE DISTRIBUTOR BLOCKS. ALSO, LARGE AMOUNTS OF CARBON HAD BUILT UP IN BOTH MAGNETO CASES, ALTHOUGH NO TRACE OF CARBON ARCING WAS FOUND.

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

IGNITION SYSTEM,MAGNETO..FAILURE,PARTIAL

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

IGNITION SYSTEM,MAGNETO..INOPERATIVE


Contributing Factors

LIGHT CONDITION..DARK NIGHT


Contributing Factors

OBJECT..TREE(S)


Contributing Factors

IGNITION SYSTEM,MAGNETO..CONTAMINATION

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