Continuous descent approach

Continuous descent approach (CDA), also known as optimized profile descent (OPD), is a method by which aircraft approach airports prior to landing. CDAs avoid long segments of flight at a level altitude by allowing aircraft to descend continuously at a constant angle. It is designed to reduce fuel consumption and noise pollution compared to other conventional descents.

A continuous descent approach starts from the top of descent, i.e., at cruise altitude, and allows the aircraft to fly its optimal vertical profile down to runway threshold. Some airports apply constraints to this individual optimal profile.