Expert: Ned Dolan - 12/7/2009

Question
what is the average decent angle on commercial airplanes? does it remain the same from beginning to end? and at the end of the decent, as you are approaching the air port, what is that decent angle?

Answer
Hi Spiro,

A jet aircraft descending from altitude is constrained by air traffic in most instances. However the industry and government are working hard to reduce these constraints in an effort to improve fuel consumption for the aircraft.

If there was no traffic a pilot would descend with idle power. The rate would vary a little between aircraft types, but would typically be about 3 to 1. That is three miles forward for each 1000 feet lost.

This rate would continue until an altitude of about 2000 feet is reached. At that time the aircraft would configured to the approach and landing configuration with the flaps and gear extended. The descent would be about 1 to .33. That is about 1 mile forward for each 300 feet lost.

I hope this helps.  Ned