The Silent Aircraft Initiative is a study being undertaken by the Cambridge-MIT Institute to discover ways to reduce aircraft noise dramatically, to the point where it would be virtually unnoticeable to people outside the airport perimeter. Launched in November 2003, the program has the support of Rolls-Royce, Boeing and Marshall Aerospace.Part of the study is examining if a steeper continuous descent into an airport will reduce approach noise levels. Theoretical analysis will be backed up by field trials using real jetliners. The study is funded by the UK Treasury and industrial partners.