NTSB Identification: LAX97FA086.
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Accident occurred Sunday, January 12, 1997 in SAIPAN ISLAND, Northern Mariana Islands
Probable Cause Approval Date: 09/04/1998
Aircraft: Enstrom F28A, registration: N9087
Injuries: 2 Fatal,3 Serious.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
Shortly before 1510, the pilot started the helicopter's engine, then departed on a sightseeing tour flight around the island with two fare-paying passengers. The operator anticipated the flight would last between 0.5 and 0.7 hrs. For weight considerations, the fuel load had been reduced before takeoff by an estimated 10 gallons bringing the usable quantity to between 16 and 19 gallons, as estimated using a dipstick. About 1558, while cruising off shore & nearly parallel to the shoreline, witnesses observed the helicopter fly past while making sounds like its engine was sputtering, stalling, or cutting in and out. The helicopter's course remained unchanged, & seconds later, other witnesses heard a loud bang sound. The helicopter then entered a rapid descent, & impacted in about 2.5-foot-deep ocean water in front of a hotel where people were swimming. An exam of the wreckage revealed a main rotor blade had impacted & severed the tail rotor drive shaft. No evidence was found indicating the pilot had practiced autorotations in the Enstrom helicopter during the 4.5 months since becoming rotorcraft rated. During the structural airframe and engine examinations, no evidence was found of precipitating mechanical malfunctions. Calculations based on maximum anticipated fuel consumption rates, and approximations for the quantity of fuel on board, revealed fuel exhaustion could occur within 0.1 hour of the flight's duration.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: loss of engine power due to fuel exhaustion, resulting from improper planning/decision; and the pilot's abrupt handling of the flight controls, while maneuvering to avoid swimmers, which resulted in main rotor blade contact with the tail boom. A related factor was: the presence of swimmers in the emergency landing area, which likely motivated the pilot to alter his approach for a forced/autorotative landing. Full narrative available
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