Helicopter Engine Failure During Cruise Flight (N349AL)

Incident Overview and Pilot Actions During cruise flight at 1,200 feet MSL, 22 miles south of its destination, the helicopter experienced a total loss of engine power. The pilot confirmed the engine failure, issued a May Day call, and initiated an autorotation toward the water. Emergency floats were inflated before impact. As the helicopter approached the surface, the pilot pulled all available collective pitch. The aircraft impacted the water in a slight nose-low, right-banking attitude, causing the right front float bag to rupture. The helicopter rolled right and remained floating inverted while the pilot egressed. The pilot later reported difficulty determining the helicopter's height above the water, according to an FAA inspector. Weather conditions were visual meteorological conditions (VMC) with a southwest wind estimated at 10 knots and wave heights of two to three feet. ## Technical Findings Examination of the helicopter revealed that the power control (PC) air line between the tee for the power turbine governor and the fuel control was fractured under the “B” nut at the fuel control. Testing at the NTSB Materials Laboratory identified fatigue cracking within the flared portion of the tube end. The origin areas were located on the inside surface of the tube at circumferential scoring marks. These marks corresponded approximately to the inside diameter of the fitting (“B” nut) that mates with the flared end. The engine maintenance manual states that excessive torque on pneumatic sensing system connections can result in cracking of the flare or the adjacent tube area in contact with the ferrule.