A lack of qualified personnel contributed to a fatal crash off the Japanese coast in 2018 involving U.S. military aircraft stationed at Marine Corps Air Station Iwakuni, in Yamaguchi Prefecture, a military report has said.

The report, released earlier this month, re-examined two separate accidents, in December 2018 and April 2016, over the Western Pacific both involving F/A-18 aircraft of Marine All Weather Fighter Attack Squadron 242, a tactical aircraft squadron, and KC-130 tankers, with the 2018 collision claiming six lives.

"Marine Corps manning practices have unintentionally detailed well below average first-tour aviators in disparate proportions" in a most challenging flight environment and at the squadron, the report said.