20160716021059A

ON THE DAY OF THE ACCIDENT, 07/16/2016 , ^PRIVACY DATA OMITTED^ AND ^PRIVACY DATA OMITTED^ WENT TO LOOK AT ^PRIVACY DATA OMITTED^ HELICOPTER , 1998 SCHWEIZER MODEL 269C-1, N6148D. THE ^PRIVACY DATA OMITTED^PILOT, ^PRIVACY DATA OMITTED^ ^PRIVACY DATA OMITTED^ ASKED ^PRIVACY DATA OMITTED^ (700HRS TT) TO FLY THE HELICOPTER, BUT ^PRIVACY DATA OMITTED^ ADVISED ^PRIVACY DATA OMITTED^ THAT HE WAS NOT PROFICIENT TO FLY WITH ^PRIVACY DATA OMITTED^. SO THE FLIGHT DEPARTED WITH THE ^PRIVACY DATA OMITTED^PILOT ^PRIVACY DATA OMITTED^ IN THE LEFT SEAT AND ^PRIVACY DATA OMITTED^ (1800 HRS TT) IN THE RIGHT SEAT; ^PRIVACY DATA OMITTED^ PERFORMED TWO AUTOROTATIONS TO TOUCHDOWN WITH NO ISSUES.

AFTERWARDS, ^PRIVACY DATA OMITTED^ EXITED THE HELICOPTER AND TOLD ^PRIVACY DATA OMITTED^ TO GET IN, WHICH HE DID AND WAS SEATED IN THE LEFT SEAT. THE FLIGHT DEPARTED AND ^PRIVACY DATA OMITTED^ AS THE PIC FLEW AROUND THE PATTERN TWICE, HOVERED, AND DID SEVERAL ?PICK-UPS AND PUT-DOWNS? IN ADDITION TO FLYING AROUND A TAXI-WAY LIGHT. AFTER THE LAST TOUCHDOWN WHILE ON THE GROUND WITH THE ENGINE RUNNING BETWEEN 30-60 SECONDS, THEY DISCUSSED THE CORRELATOR VS. THE THROTTLE. THEY PLANNED TO TEST IT BY ADVANCING THE THROTTLE TO THE CENTER OF THE GREEN ARC AND WOULD THEN PICK-UP, BUT WOULD NOT TOUCH THE THROTTLE TO SEE THE CORRELATOR IN ACTION. ^PRIVACY DATA OMITTED^ ROLLED ON THE THROTTLE AND ^PRIVACY DATA OMITTED^ LOOKED UP AND KNEW THE RPM WAS CLIMBING BUT NOT YET AT 100 PERCENT RPM. THE HELICOPTER STARTED SHAKING A LITTLE BIT, WHICH BECAME WORSE. ^PRIVACY DATA OMITTED^ RECOGNIZED THE SHAKING AS GROUND RESONANCE, AND TOLD ^PRIVACY DATA OMITTED^ TO PICK UP OFF THE GROUND. ^PRIVACY DATA OMITTED^ PUT HIS HAND ON THE COLLECTIVE TO ASSIST RAISING THE COLLECTIVE AND NOTED IT WAS COMING UP BUT THE HELICOPTER DID NOT LEAVE THE GROUND; ^PRIVACY DATA OMITTED^ DID NOT TOUCH THE THROTTLE. ^PRIVACY DATA OMITTED^ BEGAN TO ROLL THE THROTTLE UP AND BEFORE RISING TO THE GREEN ARK THE HELICOPTER BEGAN SHAKING, AND ^PRIVACY DATA OMITTED^ TOLD ^PRIVACY DATA OMITTED^ TO PICK UP, AT WHICH TIME ^PRIVACY DATA OMITTED^ INCREASED THE THROTTLE TO FULL AND THE HELICOPTER BEGAN TO SHAKE EVEN MORE. THE HELICOPTER DID NOT LEAVE THE GROUND, AND THE SHAKING BECAME UNCONTROLLABLE AND PILOTS BRACED THEMSELVES UNTIL THE HELICOPTER CAME TO REST AND DESTROYED. IT WAS ABOUT 15 MINUTES BETWEEN THEIR INITIAL DEPARTURE AND THE ACCIDENT, APPROXIMATELY 1230 LOCAL. NEITHER PILOT WAS INJURED. AN FAA INSPECTOR REVIEWED THE LOG BOOKS AND FOUND THAT THE ANNUAL HAD BEEN EXPIRED FOR A MONTH.

POST CRASH MANUFACTURE INSPECTION OF THE DAMPENERS REVEALED THAT THE FORWARD LANDING GEAR DAMPERS WERE SIGNIFICANTLY OUT OF LIMITS; LOW AT ULTIMATE LOAD; ONE AFT LANDING DAMPER WAS SIGNIFICANTLY OUT OF LIMITS, EXCEEDED ULTIMATE LOAD PRIOR TO REACHING ULTIMATE STROKE; ONE AFTER LANDING GEAR DAMPER WAS SLIGHTLY OUT OF LIMITS, UNDER CHARGED. THE CONDITION OF THE DAMPERS COULD HAVE LED TO THE INITIAL VIBRATION BUT THE INCORRECT ACTION OF THE PILOTS INCREASED THE VIBRATION RESULTING WITH THE ACCIDENT. HAD THE PILOTS FOLLOWED THE CORRECT PROCEDURES AND REDUCED POWER AND LOWERED COLLECTIVE THE VIBRATION WOULD HAVE GONE AWAY AND THERE WOULD NOT HAVE BEEN AN ACCIDENT. ACCORDING TO INFORMATION FROM THE FAA HELICOPTER FLYING HANDBOOK, FAA-H-8083-21A.