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NTSB Identification: SEA98LA022. The docket is stored in the (offline) NTSB Imaging System.

Accident occurred Tuesday, December 09, 1997 at SILVERDALE, WA

Aircraft: Cessna 150J, registration: N51369

Injuries: 2 Uninjured



Event: 20001208X09384 Status: Final Report Approved On Monday, May 04, 1998



NTSB Preliminary Narrative (6120.19A)



On December 9, 1997, approximately 1600 Pacific standard time, a Cessna 150J, N51369, nosed over during a forced landing near Silverdale,

Washington. The certified flight instructor and her student were not injured, but the aircraft, which was being leased by Alternate Air, Inc.,

sustained substantial damage. The 14 CFR Part 91 instructional flight, which departed Boeing Field, Seattle, Washington, about 45 minutes earlier,

was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation.



In a written statement, the flight instructor reported that during the recovery from the third of a series of power-off stalls, the engine began to

run rough. The flight instructor stated that power was applied smoothly and carburetor heat was turned off as part of the stall recovery

procedure. The engine continued to run rough and after approximately five seconds, the engine quit. The pilot stated that she took over the

controls from the student pilot and attempted to restart the engine. During the first attempt, the propeller turned twice, but the engine did not fire.

She then pulled the starter handle for a second restart attempt, but when she pulled it, the handle separated from the panel. At that point she

picked out a field in which to land. The touchdown, which was made on the main gear, was uneventful, but when the nose gear was lowered

onto the soft terrain, it sank in and the aircraft nosed over.



During telephone interviews with both the flight instructor and student, they reported that carburetor heat was used during each power-off

maneuver.



A METAR observation taken at 1615, at Bremerton Airport, which is about seven miles south of the accident site, recorded a temperature of

seven degrees Celsius and a dew-point of six degrees Celsius. According to the Carburetor Icing Probability Chart, the aircraft was operating in

temperature and humidity conditions where severe icing is probably at both cruise and climb power.



After the aircraft was recovered from the field, a Federal Aviation Administration Inspector from the Seattle Flight Standards District Office

supervised an engine test run. The engine was started and run-up to 2500 rpm. The operation was smooth, with no discrepancies noted. At

1700 rpm, both magnetos were checked. The right hand magneto position indicated a 90 rpm drop, and the left hand magneto position indicated

a 125 rpm drop. The carburetor heat control was positioned to the "on" position, and a 110 rpm drop was observed. The mixture control

operated correctly. The engine pull-to-start knob was inspected and it was found that the knob had pulled off the metal shaft and the metal shaft

had pulled away from the cable to the starter lever.



NTSB Final Narrative (6120.4)



The flight instructor stated that as the student pilot was recovering from the third of a series of power-off stalls, the engine began to run rough.

Power was applied smoothly and carburetor heat was turned off. The engine continued to run rough, and after approximately five seconds, the

engine quit. The flight instructor took over the controls from the student and attempted to restart the engine. During the second restart attempt,

the flight instructor pulled the starter handle, however, the handle separated from the panel. A forced landing was made to a soft field where a

successful touchdown was accomplished, but during the landing roll, the nose wheel dug in and the airplane nosed over. During the

postaccident inspection, the engine was run to 2500 rpm. The engine operated smoothly, with no discrepancies noted. Both magnetos were

checked and found operational. The carburetor heat control was checked and found operational. The engine pull-to-start knob was inspected

and it was found to have pulled off the metal shaft that runs through the panel, and the metal shaft had pulled away from the cable that runs to

the starter lever.



NTSB Probable Cause Narrative



Ice accumulation in the carburetor throat. Factors include conditions conducive to serious carburetor icing, an inoperative starter due to a

separated pull-to-start knob, and soft terrain at the location of the forced landing.

Occurrences and Sequence of Events

Occurrence: 1, LOSS OF ENGINE POWER

Phase of Operation: MANEUVERING



Sequence of Events for Occurrence Number: 1

1 ( Factor ) WEATHER CONDITION / CARBURETOR ICING CONDITIONS / (0)

2 ( Cause ) FUEL SYSTEM, CARBURETOR / ICE / (0)

3 ( Factor ) ENGINE ACCESSORIES, ENGINE STARTER / INOPERATIVE / (0)



Occurrence: 2, FORCED LANDING

Phase of Operation: EMERGENCY DESCENT/LANDING



Occurrence: 3, NOSE OVER

Phase of Operation: LANDING - ROLL



Sequence of Events for Occurrence Number: 3

1 ( Factor ) TERRAIN CONDITIONS / SOFT / (0)


 

 

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