William Perry, US Defence Secretary, said the ex-gratia payments were being offered because of the 'humanitarian nature' of the work being carried out by Major Harry Shapland, 28, and Lt-Col Jonathon Swann, 51, when they were shot down by US F-15 jets.
Major Shapland, of Henley, Oxfordshire, and Lt-Col Swann, of Knebworth, Hertfordshire, were among 26 passengers flying in two UN Blackhawk helicopters. The US jets mistook their aircraft for a Russian-built Iraqi helicopter as they flew over the no-fly zone established to protect the Kurds in northern Iraq in April. Everyone on board died.
A US inquiry concluded that the tragedy occurred after a series of catastrophic errors, including failure to warn the jet pilots of the presence of allied aircraft, and incorrect programming of recognition equipment.
Mr Perry told the UN that the payment was in recognition of the unique circumstances of the aircraft accident.
A spokesman for the Ministry of Defence in London said: 'Such payments are extremely rare and we are grateful to the US for making the exception in this case.'