PEARLAND, TX, USA
N16814
BELL 206B
DURING A MAINTENANCE FLIGHT CHECK FOLLOWING A TURBINE REPLACEMENT, A TOTAL LOSS OF ENGINE POWER OCCURRED. AS THE PILOT BEGAN TO CUSHION WITH COLLECTIVE DURING THE AUTOROTATION THE HELICOPTER TOUCHED DOWN, ROCKED FORWARD AND THEN BACK. THE MAIN ROTORS SEVERED THE TAILBOOM. EXAMINATION OF THE ENGINE REVEALED A LACK OF OIL TO THE NUMBER EIGHT BEARING ASSEMBLY.
On August 4, 1993, at 1400 central daylight time, a Bell 206B, N16814, sustained substantial damage during a forced landing near Pearland, Texas. The airline transport rated pilot and a mechanic aboard the helicopter were not injured. Visual meteorological conditions prevailed for the local maintenance check flight. The Pilot/Operator report and statement submitted by the pilot reported that he performed the preflight, and after a 10 minute ground run was cleared for takeoff. During initial climbout, at approximately 200 to 280 feet above the ground (AGL), the engine made a noise and decelerated. An autorotation was initiated to an open field. The pilot stated that "at about 30 to 40 feet I began a gentle deceleration and reduced my ground speed to about 0 at about 4 feet and waited for the aircraft to settle, then I began to cushion with collective." He further stated "the aircraft touched down and rocked forward and then back." During the backward movement, the pilot heard a loud bang. Damage to the helicopter included a severed outboard portion of the tailboom. The mechanic reported in the enclosed statement that he was aboard the helicopter for a maintenance operational flight check following a turbine replacement. He further reported that the engine "seized at about 300 feet" above the ground. Examination of the engine by the operator and FAA inspectors (enclosed statement) indicated a lack of lubrication to the number eight bearing. The representative of the engine manufacturer (enclosed report) examined the engine and found that the #8 bearing was "not fully engaged with the groove in the G. P. Support and the bearing had partially failed."
PILOT'S FAILURE TO MAINTAIN PROPER ROTOR RPM, THE DELAYED FLARE, AND IMPROPER TOUCHDOWN. FACTORS WERE TOTAL FAILURE OF THE POWER TURBINE DUE TO OIL STARVATION TO THE #8 BEARING ASSEMBLY.
Source: NTSB Aviation Accident Database
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