Accident Sequence
On 2 May 2018, at approximately 1127 local time, a WC-130H aircraft, tail number 65-0968, assigned to the Puerto Rico Air National Guard’s 156th Airlift Wing, crashed about 1.5 miles northeast of Savannah/Hilton Head International Airport (KSAV), Georgia. All nine individuals on board perished: Mishap Pilot 1 (MP1), Mishap Pilot 2, Mishap Navigator, Mishap Flight Engineer, Mishap Loadmaster, and four mission essential personnel.
The aircraft had been at KSAV since 9 April 2018 for scheduled fuel cell maintenance and unscheduled work on engine number one, performed by 156th Airlift Wing maintenance personnel using facilities of the 165th Airlift Wing. The mission was to fly the aircraft to the 309th Aerospace Maintenance and Regeneration Group at Davis-Monthan Air Force Base, Arizona, for removal from service.
During the takeoff roll, engine one’s revolutions per minute (RPM) fluctuated and did not reach normal levels when MP1 advanced the throttle into the flight range. Approximately eight seconds before rotation, engine one RPM and torque significantly decayed, substantially reducing thrust. The crew did not recognize the fluctuation and performance decay until rotation, when MP1 noted challenges controlling the aircraft and the plane veered left, nearly departing the runway onto grass before becoming airborne at about 1125 local.
After retracting the landing gear, the crew identified the engine one malfunction, and MP1 called for engine shutdown. However, the crew failed to execute the Takeoff Continued After Engine Failure procedure, the Engine Shutdown procedure, and the After Takeoff checklist as required by the Flight Manual. The flaps remained at 50 percent. Additionally, MP1 banked left toward the inoperative engine, continued climbing, and applied variable left and right rudder inputs.
At an altitude of approximately 900 feet mean sea level and an indicated airspeed of 131 knots, MP1 input over nine degrees of left rudder. The aircraft skidded left, the left wing stalled, and the aircraft departed controlled flight, impacting terrain on Georgia State Highway 21.
Probable Cause
The board president determined, by a preponderance of the evidence, that the cause of the mishap was MP1’s improper application of left rudder, resulting in a skid below three-engine minimum controllable airspeed, a left-wing stall, and departure from controlled flight. Additional contributing factors included the crew’s failure to adequately prepare for emergency actions, failure to reject the takeoff, failure to properly execute after takeoff and engine shutdown checklists and procedures, and the maintenance personnel’s failure to properly diagnose and repair engine number one.