# What is the speed and inclination angle of a commercial plane during descent?

I have a question based on flight track logs on https://flightaware.com.

In one of the logs I'm looking at, it says that at time 08:16:15 PM the altitude was 36,000 ft and plane speed was at 473 mph. At time 08:16:58 PM, the plane descended to 35,400 ft.

I did some rough calculations and realized that the speed 473 cannot be along the vertical plane. Then, what is this speed? Is it along the descent path? Also, what angle do planes make with the vertical plane when descending? Where can I get this information?

• Why would you even think that is vertical speed? (Assuming that flightaware is accurate in both time and altitude) A difference of 600 feet in 43 seconds works out to a descent rate of 850 fpm, which is completely normal. – abelenky May 4 '18 at 16:20
• Normal takeoff pitch (“longitudinal axis against horizon”) angle is, as a rule of thumb, about 15 degrees; normal takeoff flight path angle („height/distance“) maybe 10 degrees (note: an aircraft rarely points where it goes in the vertical plane; most aircraft - unless there is very strong wind - usually point above where they go). After takeoff, climbing to cruise altitude, both angles will be lower. For descent, it’s about 0-3 degrees pitch, and -3 degrees flight path angle. Every single flight will deviate from the above, but as an average order of magnitude, this should work quite well. – Cpt Reynolds May 4 '18 at 19:31