LAKE TAHOE, CA, USA
N4838P
PIPER PA-23-250
APPROACHING THE ARPT, THE PLT RECEIVED LDG INSTRUCTIONS. SECONDS LATER, HIS TRANSMISSIONS WERE ABRUPTLY TERMINATED. WITNESSES OBSERVED THE ACFT ABRUPTLY NOSE OVER & DESCEND INTO WATER AT A HIGH RATE OF SPEED. IT FRAGMENTED UPON IMPACT & IMMEDIATELY SANK. THE ACFT HAD RECENTLY UNDERGONE MAINTENANCE INVOLVING THE REMOVAL & INSTALLATION OF ITS WINGS, & INSTALLATION OF AN AUTOPILOT & ELECTRIC TRIM. FOLLOWING THIS WORK, THE ACFT WAS FLIGHT TESTED. DURING THE TEST, THE PLT EXPERIENCED A LOSS OF CONTROL & THE ACFT PITCHED DOWN IN A MANNER SIMILAR TO THAT DESCRIBED BY WITNESSES TO THE ACCIDENT. EXAM OF THE UPPER STABILATOR PULLEY ASSEMBLY REVEALED THAT ITS RESPECTIVE CONTROL CABLE HAD BEEN WORKING AGAINST THE SIDE OF THE PULLEY. THE PULLEY WAS FRACTURED, & THE CABLE HAD BECOME WEDGED IN THE PULLEY, WHICH (IN TURN) HAD BECOME WEDGED AGAINST THE SIDE OF ITS SUPPORT BRACKET. THIS ACTION RESTRICTED STABILATOR MOVEMENT.
DISABLEMENT OF THE STABILATOR FLIGHT CONTROL SYSTEM. A CONTRIBUTING FACTOR WAS: INADEQUATE MAINTENANCE.
Source: NTSB Aviation Accident Database
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