The Japanese Air Self-Defense Force concluded Friday that the crash in April of an F-35A stealth fighter into the Pacific Ocean was caused by the pilot experiencing "spatial disorientation" and not by any mechanical problem.The conclusion is in line with an interim investigative report in June which pointed to human error. The report's findings were based on the ASDF's probe as well as experts' analyses of radar data and records of communication with other F-35As that were flying with it at the time during training.Related coverage:Japan resumes F-35A flights 4 months after fatal crashREAD FULL ARTICLE