NTSB Identification: LAX88LA179.
The docket is stored on NTSB microfiche number 39071.
Accident occurred Friday, May 13, 1988 in WAIALUA, HI
Probable Cause Approval Date: 07/09/1990
Aircraft: McDonnell Douglas 369D, registration: N4943T
Injuries: 1 Serious.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

THE HELICOPTER WAS RETURNING TO ITS LONG LINE PICKUP POINT FOR ANOTHER LOAD WHEN IT ENTERED AN UNCOMMANDED LEFT ROLL. THE PILOT REGAINED CONTROL OF THE HELICOPTER, RELEASED THE LONG LINE CABLE AND ENTERED A SHALLOW, SLOW APPROACH TO A HOVER IN A VACANT AREA. AS THE SKIDS NEARED THE GROUND THE HELICOPTER ROLLED LEFT TO AN ANGLE OF 45 DEGREES, BEGAN TO CLIMB, THEN CRASHED INTO AN IRRIGATION DITCH. THE EXAMINATION REVEALED METAL PARTICLES CONTAMINATING THE TRIM ACTUATOR SWITCH. ACCORDING TO THE MANUFACTURER, THE HELICOPTER IS CONTROLLABLE WITH A MALFUNCTIONING TRIM SYSTEM; HOWEVER, THE CIRCUIT BRAKERS SHOULD BE PULLED. THE PILOT STATED HE RESET THE CIRCUIT BREAKERS.

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

FAILURE TO FOLLOW PROCEDURES ESTABLISHED BY THE MANUFACTURE FOR UNCOMMANDED TRIM INPUTS AND HIS DECISION TO MAKE A HOVER APPROACH TO LANDING.

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