NTSB Identification: ATL84LA205.
The docket is stored on NTSB microfiche number 24847.
Accident occurred Wednesday, June 20, 1984 in IVA, SC
Aircraft: SIKORSKY CH-19E, registration: N4721
Injuries: 1 Uninjured.

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 BEING OPERATED FROM SLOPING TERRAIN. AFTER RETURNING FROM A SPRAY MISSION, THE PLT REMAINED INSIDE THE HELICOPTER WITH THE ENG & ROTOR AT GROUND IDLE WHILE THE GROUND CREW REFILLED THE SPRAY TANK. AFTER COMPLETING THE LOADING OPERATION, THE PLT BEGAN APPLYING POWER TO INCREASE THE ROTOR RPM FOR TAKEOFF. A SEVERE GROUND-RESONANCE TYPE OF VIBRATION DEVELOPED. THE PLT DISENGAGED THE ENG & APPLIED THE ROTOR BRAKE. WHEN THE ROTOR HAD STOPPED & THE ENG WAS SECURED, THE PLT EGRESSED & OBSERVED THAT THE AFT END OF THE TAIL BOOM WAS LAYING ON THE GROUND. NO PRE-ACCIDENT CRACKS OR FAILURES WERE FOUND IN THE TAIL BOOM. SOME COMPONENTS OF THE ROTOR SYS HAD CRACKS, BUT NONE HAD FAILED OR SEPARATED. THE MAIN ROTOR LEAD-LAG DAMPERS WERE REMOVED & CHECKED FOR TIME & ALL WERE WITHIN SPECIFICATIONS. PERSONNEL WHO RECOVERED THE HELICOPTER NOTED THAT THE LEFT FRONT LANDING GEAR STRUT WAS FLAT & THE LEFT REAR MAIN LANDING GEAR STRUT WAS LOW. THEY ESTIMATED THE TERRAIN WAS SLOPING 10 DEGS.

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

OPERATION WITH KNOWN DEFICIENCIES IN EQUIPMENT..CONTINUED..PILOT IN COMMAND

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

FUSELAGE..VIBRATION



Contributing Factors

LANDING GEAR,MAIN GEAR STRUT..PRESSURE TOO LOW


Contributing Factors

MAINTENANCE,SERVICE OF AIRCRAFT/EQUIPMENT..IMPROPER


Contributing Factors

TERRAIN CONDITION..ROUGH/UNEVEN

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