To mark Recording the occasion , the band 's set began Process_start with a Spitfire flyover , an event Social_event which was mirrored at the tour Traveling 's final concert Social_event at Knebworth , which was preceded by a First World War Hostile_encounter air display , organised Arranging and featuring Cause_to_be_included vocalist Bruce Dickinson .

The low-speed flyover , with landing gear down , was supposed to take place Process_start at an altitude of 100 feet ( 33 metres ) ; instead , the plane performed Hold the flyover at 30 feet , skimmed Motion the treetops of the forest at the end of the runway ( which had not been shown Protest on the airport map given to the pilots ) , and crashed Catastrophe .

The low-speed flyover , with landing gear down , was supposed to take place Process_start at an altitude of 100 feet ( 33 metres ) ; instead , the plane performed Hold the flyover at 30 feet , skimmed Motion the treetops of the forest at the end of the runway ( which had not been shown Protest on the airport map given to the pilots ) , and crashed Catastrophe .