Incident Details
On December 6, 2009, at approximately 1030 Pacific standard time, an Aerospatiale AS 355F1 helicopter, registration N548SA, sustained substantial damage when the left engine cowling door opened during cruise flight near Temple Bar, Arizona. The helicopter was operated by Heli-USA Airways, Inc., under Title 14 Code of Federal Regulations Part 135. The commercial pilot and six passengers were not injured. Visual meteorological conditions prevailed, and a company flight plan was filed for the cross-country air tour flight. The flight originated from McCarran International Airport, Las Vegas, Nevada, about 1000, with an intended destination of Grand Canyon, Arizona.
Pilot Report
The pilot reported that on the morning of the accident, he arrived at work approximately 40 minutes late due to unforeseen traffic and local events. Upon arrival, he began the pre-flight inspection. While inspecting the left engine area, a fuel truck arrived to refuel the helicopter. The pilot lowered the cowling door and walked to the pilot seat to retrieve the gas cap keys. After refueling, the pilot continued the pre-flight without realizing he had left the engine cowling unlatched. The passengers were dropped off on the ramp, and the pilot proceeded to board them, still unaware of the unlatched cowling.
During the cruise flight, the pilot heard a "pop" followed by a "shake feed" in the cyclic control. He contacted a second company helicopter to visually inspect his aircraft in flight. The second pilot reported that the left engine cowling appeared open and partially separated. The pilot then initiated a precautionary landing on the desert surface, and the helicopter landed without further incident.
Damage
Examination by a Federal Aviation Administration inspector revealed damage to two of the three main rotor blades. One blade exhibited a one-inch long gouge approximately one-quarter inch deep near the blade root. A portion of the left engine cowling had separated and was not located.