What happened
On February 26, 2008, an AS332L2 helicopter, registration PP-MUM, departed from the P-18 offshore platform in the Campos Basin, near the coast of Rio de Janeiro. The flight was operating under Instrument Flight Rules (IFR) toward Macaé, carrying two crew members and seventeen passengers.
During the initial climb, while performing a left-hand turn under visual meteorological conditions, the aircraft lost airspeed and subsequently lost flight control. The helicopter entered an anti-clockwise spiral descent, impacting the sea approximately 300 meters from the departure platform. The impact caused the tail section to separate and several flotation bags to burst. While the aircraft partially floated, the cabin remained submerged for approximately one hour.
Of the twenty people on board, four passengers and the pilot were killed. The remaining thirteen passengers and two crew members were rescued from the water.
The investigation
CENIPA investigators examined the aircraft wreckage, which was recovered from the seabed, and analyzed the flight profiles and maintenance records. The investigation focused on the flight dynamics during the turn and the environmental conditions of the offshore operation. Investigators also reviewed the maintenance history of the aircraft, noting that a preventive maintenance inspection had been performed just one day prior to the accident. Additionally, the investigation looked into a reported intermittent malfunction regarding the cyclic trim release button that had been verbally communicated during a previous flight but was not documented in the aircraft's technical logs.
Findings
- The primary cause of the accident was spatial disorientation.
- The aircraft was operating in an environment where the homogeneity of the sea surface provided very little visual contrast, making it difficult to perceive the horizon.
- A reported intermittent fault in the cyclic trim release button was not recorded in the aircraft's maintenance logs.
- The impact with the ocean surface was severe enough to cause structural failure of the tail section.