NTSB Identification: ATL83FA044
14 CFR Part 91: General Aviation
Accident occurred Tuesday, November 23, 1982 in ALABASTER, AL
Probable Cause Approval Date: 11/23/1983
Aircraft: ROBINSON R-22, registration: N90218
Injuries: 2 Uninjured.

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.

THE PILOT REPORTED THAT SHORTLY AFTER TAKEOFF, HE NOTICED THE RPM'S BEGAN FALLING. HE STATED THAT HE INCREASED THE THROTTLE AND LOWERED THE COLLECTIVE, BUT THE RPM'S CONTINUED TO DECREASE UNTIL THE LOW RPM WARNING HORN CAME ON. AN AUTOROTATIVE LANDING WAS MADE. DURING TOUCHDOWN, WHILE THE HELICOPTER STILL HAD FORWARD SPEED, THE SKIDS DUG INTO THE GROUND AND THE TAIL MOVED UP INTO THE PATH OF THE MAIN ROTOR BLADES. THE HELICOPTER THEN TURNED AND CAME TO REST ON ITS SIDE. AN EXAMINATION REVEALED THE AIR-FILTER CARTRIDGE WAS COVERED WITH OIL, DIRT AND OTHER CONTAMINENTS; THE 4 V-DRIVE BELTS WERE FROM DIFFERENT MANUFACTURERS AND WERE OF DIFFERENT LENGTHS; THE ENGINE DRIVE ACTUATOR (PULLEY) VALLEYS WERE DEEPLY GROOVED AND WORN, THE EXHAUST MUFFLER HAD PIECES OF THE FLARE TUBE FLOATING LOOSE INSIDE THE MUFFLER. DURING A TEST RUN, THE ENGINE OPERATED NORMALLY. A TEARDOWN OF THE TRANSMISSION REVEALED NO PREIMPACT FAILURES.

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

REASON FOR OCCURRENCE UNDETERMINED


Contributing Factors

EXHAUST SYSTEM,END PLATE..BLOCKED(PARTIAL)


Contributing Factors

FUEL SYSTEM,RAM AIR/INDUCTION AIR..BLOCKED(PARTIAL)


Contributing Factors

ROTOR DRIVE SYSTEM,MAIN ROTOR DRIVING PULLEY..WORN

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