19980122003819A

NSDA FLIGHT. LOUD SQUEAL. ROTOR DECAY. AUTOROTATED DRY CREEK BED. CHOPPED TAIL DRIVE ADAPTER LOST BOOT AND GREASE. (-23) THE ACCIDENT OCCURRED APPROXIMATELY 20 MILES SOUTH OF ROCKSPRING TEXAS ON THE BACON RANCH AT 10:15 AM CENTRAL TIME ON JANUARY 22, 1998. THE PILOT AND ONE CREW MEMBER WERE CONDUCTING AEIRAL HUNTING FOR THE US DEPARTMENT OF AGRICULTURE. THE OWNER OF THE AIRCRAFT IS THE PILOT GREG OBERT OWNER OPERATOR OF GO HELICOPTERS, ^PRIVACY DATA OMITTED^ FAA INSPECTORS ARRIVED THE AFTERNOON AFTER THE ACCIDENT. THE AIRCRAFT WAS IN A VERY REMOTE LOCATION ON A CATTLE RANCH. IT WAS ABOUT 75 FEET DOWN IN A WIDE GULLY, IN THE BOTTOM OF THE GULLY IS A DRY RIVER BED. THE AREA IS COVERED WITH BRUSH AND TREES RANGING FROM 3 TO 20 FEET TALL. THE BANK OF THE CREEK BED IS ABOUT 2 TO 3 FEET HIGH. THE PILOT INDICATED HE WAS CRUISING AT ABOUT 75 FEET AGL AND 50 KNOTS OVER THE GULLY WHEN HE HEARD A LOUD SQUEALING SOUND FROM THE BACK OF THE AIRCRAFT. HE SAID HE REDUCED POWER AND ATTEMPTED TO AUTOROTATE AND LAND ON THE EDGE OF THE CREEK BED. JUST BEFORE TOUCH DOWN HE OBSERVED ROTOR RPM HAD DECREASED DRASTICALLY. THE PILOT SAI D HE FLARED AT ABOUT 10 FEET AGL TO STOP FORWARD SPEED AND DESCENT RATE, THE AIRCRAFT LANDED HARD ON THE EDGE OF THE BANK AND ROCKED FORWARD INTO THE DRY CREEK CAUSING THE AIRCRAFT TO ROTATE ABOUT 180 DEGREES AND END UP ALMOST INVERTED ON IT'S RIGHT SIDE. THE PILOT THEN SAID HE SHUT THE ENGINE OFF THAT WAS STILL RUNNING AND EXITED THE WRECKAGE, HE THEN HAD TO SLIGHTLY LIFT THE WRECKAGE UP SO THE CREWMEMBER COULD CLIMB OUT FROM UNDER THE WRECKAGE. ON SITE EXAMINATION SHOWS THE HELICOPTER CAME DOWN THROUGH THE TOP OF A 20 FOOT TREE AND OTHER TREES AND BRUSH TO IMPACT THE EDGE OF THE CREEK BED HARD ENOUGH TO BEND AND BREAK ALL OF THE REAR SHOCK STRUTS, SKID TUBES AND CROSS FRAME. THIS AND SOME REMAINING FORWARD MOTION CAUSED IT TO ROCK FORWARD INTO THE DRY CREEK BED. THE BLADES CONTACTED THE TERRAIN MAKING THE HELICOPTER ROTATED COUNTERCLOCKWISE. AT THIS POINT A PART OF THE TAIL ROTOR SEPARATED AFTER STRIKING TERRAIN. THE TAIL BOOM ALSO SEPARATED AT ITS ATTACH POINT AND WAS STRUCK BY ONE OF THE BLADES AS IT DEPARTED. THE AIRCRAFT CAME TO REST ALMOST INVERTED ON THE RIGHT SIDE AGAINST SOME BRUSH IN THE CREEK BOTTOM, TWO OF THE MAIN ROTOR BLADE SOMEWHAT ATTACHED THE OTHER OFF TO ONE SIDE. EXAMINATION OF THE WRECKAGE INDICATED THERE WAS FLIGHT CONTROL AND ENGINE CONTROL CONTINUITY. EXAMINATION OF THE BELT DRIVE SYSTEM THAT PROVIDES ENGINE POWER TO THE ROTORS IT WAS DISCOVERED THAT THE LOWER COUPLING DRIVE SHAFT THAT PROVIDES ENGINE POWER TO THE LOWER PULLEY WAS NOT ENGAGED IN THE ENGINE ADAPTER AS IT SHOULD HAVE BEEN. ALSO, THE NUT LOCKWASHER AND AFT BUMPER PLUG THAT RETAINS THE LOWER COUPLING DRIVE SHAFT IN THE LOWER PULLEY ASSEMBLY WAS MISSING. THE PLUG AND HUT WERE FOUND ABOUT 5 YARDS UP THE APPROACH PATH FROM THE TOUCHDOWN POINT. PHOTOGRAPHS AND VIDEO OF THE AREA WERE TAKEN AND A SKETCH OF THE LOCATION OF THE PARTS IN RELATION TO THE AIRCRAFT WERE MADE. THE AIRCRAFT WAS TO BE MOVED TO LAREDO FOR FURTHER EXAMINATION.