What is quieter - an arrival or a departure?


Arriving aircraft at low altitudes are generally quieter than departures of the same aircraft type because this mode of flight requires much less engine power, which is the dominant source of airplane noise.  However, close to the airport, the relative quietness of arrivals may be offset by the fact that the airplanes are typically lower in altitude than departures over the same location.  Configuring the plane for landing requires the pilot to lower the landing gear and wing flaps which enables the airplane to slow down and the wings to generate greater lift. However, the noise generated by the turbulent airflow over the landing gear and flaps also creates substantial noise that can equal or exceed that produced by the jet engines.  The turbulent airflow also increases the drag on the airplane requiring the pilot to increase engine power to maintain a safe descent path to the runway, which also increases noise.