Aviation Accident Summaries

Aviation Accident Summary NYC82DA097

BROOKVILLE, NY, USA

Aircraft #1

N911X

BELL 47G-2

Analysis

WHILE RETURNING TO THE HELIPORT, THE PILOT NOTICED A DECAY IN THE ENGINE AND ROTOR RPM'S. HE ELECTED TO MAKE A PRECAUTIONARY LANDING IN A PLOWED FIELD. DURING LANDING, THE MANIFOLD PRESSURE WENT TO THE RED LINE WHILE THE RPM DECAYED. THE HELICOPTER TOUCHED DOWN SOFTLY, BUT WITH ABOUT 10 MPH FORWARD SPEED. IT ROLLED FORWARD AND TO THE RIGHT WHEN THE SKIDS DUG INTO THE SOFT GROUND. AN INVESTIGATION REVEALED THAT THE NO. 6 CYLINDER HAD A LOW COMPRESSION READINGOF 5/80 WITH BLOW-BY EVIDENT INTO THE INTAKE SYSTEM. WHEN THE CYLINDER WAS REMOVED, THE INTAKE VALVE WAS FOUND NOT TO BE SEATING PROPERLY. NO OTHER MALFUNCTION OR DEFECT OF THE ENGINE OR ENGINE CONTROLS WAS NOTED.

 

Source: NTSB Aviation Accident Database

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