The goal of silent aircraft initiative is to design a conceptual aircraft,which is inaudible outside the airport perimeter and also in fuel efficiency and emission control superior to present and future conventional aircraft.

The useages of 3 group with 3 descend modes in Boeing aircraft with which autopilot releases race-high autopilot,which release much of the workload from pilots are one of the most important factors in the safety of flight.

Based on the scenario given by the experts from the World Meteorology Organization and International Civil Aviation Organization, the effects of the current emission by subsonic aircraft on the surface ultra violet radiation is estimated by a radiative transfer model.