Families of the victims of the 1985 Japan Airlines jet crash on Monday marked the 39th anniversary of the world’s deadliest single-aircraft accident that killed 520 passengers and crew, as the carrier is enhancing safety steps following a spate of recent incidents. As in previous years, relatives of the victims climbed a steep mountain trail in the summer heat to pay their respects at the Boeing 747’s crash site on Osutaka Ridge in Gunma Prefecture, northwest of Tokyo. “I would like to pass on memories of the accident to the next generation by climbing” to the site on the anniversary, as many …