but i thought this was due to a letter from Bell. If it has been ok in the past can it be made illegal now and effectively backdated? What if you have just bought a 206 with mixed parts? Do Bell really need to kill off the Agusta Bell 206 ? Technically i would have thought that as the authorities are aware that a huge no of aircraft are flying with mixed parts and have been for decades then there should be some firm directive. What happens if some parts are not available from Agusta ? People will find a way around this problem i am sure.