Lange, his wife and other IAS members were on board the Malaysia Airlines Flight 17 when it was shot down on 17 July 2014, killing all people on board. He was 59. The flight was meant to go from Amsterdam to Kuala Lumpur, Malaysia but was shot down near Hrabove, Ukraine. He and his wife were among the 193 Dutch citizens killed. He and the IAS members were planning to go to Melbourne, Australia for the 20th International AIDS Conference, starting on 19 July.