BELLEVUE, WA, USA
N8521Z
LAKE LA-4-200-EP
THE INSTRUCTOR PLT (CFI) HAD BEEN TRAINING THE STUDENT, WHO WAS A CERTIFICATED PLT, BUT NOT SEAPLANE RATED. WITNESSES RPRTD THAT AS THE ACFT DEPARTED LAKE SAMMAMISH, THE ENG MADE UNUSUAL SOUNDS, THEN IT BECAME SILENT. ONE WITNESS RPRTD HESAW THE AIRPLANE SPINNING IN A FLAT ATTITUDE. AN INVESTIGATION REVEALED NO PREIMPACT PART FAILURE, BUT DURING A TEST, THE SPARK PLUGS WOULD NOT FIRE CONTINUOUSLY AT THE MIMIMUM ALLOWABLE OPERATIONAL PRESSURE. THE ACFT HAD BEEN EQUIPPED WITH AN EXTENDED PROPELLER HUB IN ACCORDANCE WITH STC #SA4NE. THIS MODIFICATION EXTENDED THE PROPELLER REARWARD BY 4 INCHES. THE ACFT HAD FLOWN 255 HRS SINCE IT WAS LAST INSPECTED.
LOSS OF ENGINE POWER FOR AN UNDETERMINED REASON AND FAILURE OF THE INSTRUCTOR PILOT (CFI) TO MAINTAIN CONTROL OF THE AIRCRAFT, WHICH RESULTED IN A STALL/SPIN.
Source: NTSB Aviation Accident Database
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