On 29 April 2013, shortly after take off from Bagram, sudden movement of at least one of five large items of previously-restrained cargo weighing up to 18 tons each altered the centre of gravity to the extent that the crew of a National Air Cargo Boeing 747-400 could no longer control the pitch of the aircraft and it stalled and terrain impact followed before control could be regained. The NTSB Investigation, focusing on what caused the cargo restraint system to fail and the context for that failure is ongoing but related procedural and oversight deficiencies have already been identified.