What happened
On 6 December 2018, a US Marine Corps KC-130 Hercules assigned to Marine Aerial Refueler Transport Squadron 152 departed Iwakuni Airport for a night refueling mission. During the operation over the Pacific Ocean, the tanker aircraft collided with a McDonnell Douglas F/A-18 Hornet. The impact caused both aircraft to lose control and crash into the sea approximately 200 miles from Muroto Cape, Japan.
Following the accident, search and rescue operations were conducted. Among the crew of the F/A-18, one Marine was recovered in fair condition, while another was confirmed deceased. The five crew members aboard the KC-130 Hercules remained missing after two days of searching and were presumed dead.
Findings
An investigation identified several interconnected factors that led to the collision. A primary factor was an unbriefed, non-standard departure from the tanker requested by the flight lead, which positioned the mishap pilot on the left side of the aircraft rather than the standard right side. Additionally, lighting configurations contributed to the accident; the flight lead utilized a bright external light setting while the tanker remained in a dim, covert setting. This caused the pilot of the F/A-18 to focus on the brightly lit lead aircraft instead of the dimly lit tanker.
These conditions led to a loss of situational awareness for the pilot of the F/A-18 Hornet, resulting in a drift across the top of the tanker. As the pilot maneuvered away from the lead aircraft, the wing impacted the right side of the tanker's tail section. The investigation also noted that organizational culture and command climate served as contributing factors to the mishap.