Aviation Accident Summaries

Aviation Accident Summary FTW91FA155

Aircraft #1

N3909F

BELL 412

Analysis

THE HELICOPTER WAS ON FINAL APCH TO AN OIL RIG IN THE GULF OF MEXICO, WHEN TAIL ROTOR AUTHORITY & DRCTNL CTL WERE LOST. AS THE CREW BEGAN AN AUTOROTATION TO THE WATER, THE HELICOPTER SPUN OUT OF CTL TO THE RGT. IT MADE 2 TO 3 REVOLUTIONS & IMPACTED THE WATER. THE RGT FLOATATION GEAR DEPLOYED, BUT THE LEFT FLOATATION GEAR DIDN'T DEPLOY, BECAUSE THE PNEUMATIC LINES WERE PULLED APART DRG IMPACT. SUBSEQUENLTY, THE HELICOPTER ROLLED OVER DRG TOUCHDOWN IN THE WATER. THE CREW & 10 OF 11 PSGRS ESCAPED THRU THE EMERG WINDOWS. THE OTR PSGR REMAINED IN HIS SEAT (INCAPACITATED FM INJURIES) & DROWNED. AN INVESTIGATION REVEALED THE #1 HANGER BEARING HAD OVERHEATED & DISINTEGRATED AT AN EXTREMELY HIGH TEMPERATURE. SUBSEQUENTLY, THE TAIL ROTOR DRIVE SHAFT FAILED.

Probable Cause and Findings

OVERHEATING AND SUBSEQUENT FAILURE OF THE NUMBER ONE TAIL ROTOR HANGER BEARING FOR AN UNDETERINED REASON, AND FAILURE OF THE TAIL ROTOR DRIVE SHAFT.

 

Source: NTSB Aviation Accident Database

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