What happened
On August 19, 2011, an AW139 helicopter, registration PR-SEK, was performing an offshore passenger transport flight from the P-65 platform to Macaé, Brazil. During the climb phase of the flight, a tail rotor blade separated from the aircraft. This structural failure immediately compromised the aircraft's controllability. Within seven seconds of the blade separation, the crew lost control of the helicopter, which entered an abnormal attitude and collided with the sea in the Campos Basin. The impact caused the aircraft to submerge and be destroyed. All four occupants—two crew members and two passengers—sustained fatal injuries.
The investigation
CENIPA investigators analyzed flight data from the cockpit voice and flight data recorder (CVFDR), which were processed with assistance from the NTSB (USA) and ANSV (Italy). The investigation focused on the sequence of events following the separation of the tail rotor component. Investigators examined the mechanical integrity of the tail rotor assembly and the tail gear box (TGB). The analysis also explored a potential "cascade effect" involving the failure of the Tail Rotor Shut-Off Valve (TRSOV) pilot valve. Furthermore, the investigation looked into the relationship between the structural failure of the blade and the electrical failure of the hydraulic valve components, as well as the adequacy of existing maintenance directives and simulator training for such extreme emergency scenarios.