IVA, SC, USA
N4721
SIKORSKY CH-19E
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.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
