The Defensive Aids Sub-System (DASS) for the Eurofighter Typhoon continues to be a collaborative effort between the UK, Italy, Germany and Spain. In the early 1990s and the infancy of the contract, Germany and latterly Spain withdrew from the four-nation partnership. However, by the mid-1990s, both countries re-joined the programme, realising the four-nation partnership that continues today.

The following timeline details the significant milestones since the early 1990s.