KAHULUI, HI, USA
N350CB
AEROSPATIALE AS-350-B
THE PURPOSE OF THE PLANNED 5 MIN LONG NIGHT FLIGHT WAS TO REWARD ONE OF THE OPERATOR'S CUSTOMER'S EMPLOYEES FOR THEIR SALES PERFORMANCE RECORD. THE FLT INVOLVED A VIEW OF THE CITY. THE PILOT HAD EARLIER MADE A SIMILAR FLT, & DURING TAKEOFF HE HAD TURNED OFF THE HELICOPTER'S LANDING LIGHT TO 'AMPLIFY THE VISUAL EFFECT' OF THE RUNWAY LIGHTS. THE HELICOPTER'S MANUFACTURER HAD DESIGNED THE LIGHT SWITCH TO BE LOCATED ADJACENT TO THE HYDRAULIC TEST SWITCH. UPON DEPRESSION OF THE LIGHT SWITCH THE HELICOPTER'S LIGHT TURNED OFF. UPON DEPRESSION OF THE HYD TEST SWITCH THE HYD BOOST SYSTEM DEACTIVATED, THE CONTROLS STIFFENED & A WARNING HORN SOUNDED. DURING THE AERIAL TAXI FOR TAKEOFF, BETWEEN 25 & 50 FT AGL, THE PILOT INADVERTNETLY MISTOOK & DEPRESSED THE HYD TEST SWITCH FOR THE LIGHT SWITCH, & THE WARNING HORN ACTIVATED. WHEN THE PILOT RELEASED THE COLLECTIVE CONTROL TO SILENCE THE HORN THE COLLECTIVE LOWERED & THE HELICOPTER DESCENDED UNTIL TOUCHING DOWN HARD ON THE TAXIWAY.
THE PILOT'S INADVERTENT DEACTIVATION OF THE HELICOPTER'S HYDRAULIC BOOST SYSTEM AND HIS IMPROPER REMEDIAL ACTION THEREAFTER TO THE INFLIGHT SITUATIONS WHICH HE CREATED. A CONTRIBUTING FACTOR WAS RELATED TO THE MANUFACTURER'S INADEQUATE LOCATION AND DESIGN (SHAPE) OF THE HYDRAULIC TEST SWITCH.
Source: NTSB Aviation Accident Database
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