Why is the landing rollout longer at higher altitude airports?

The landing rollout is longer at higher altitude airports primarily due to the combination of factors involving less effective reverse thrust and faster ground speed.

At higher altitudes, the air density is lower. This reduced density impacts several aspects of aircraft performance. The engines and reverse thrust mechanisms rely on sufficient air to generate thrust, and when air density is low, their efficiency in providing reverse thrust is diminished. Consequently, aircraft cannot decelerate as effectively during rollout.

Additionally, when an aircraft descends from altitude, it’s important to note that its true airspeed at that altitude is faster than it would be at sea level due to the reduced air density. Although the indicated airspeed may appear normal, the true airspeed—and consequently the ground speed—remains higher, leading to longer stopping distance required upon landing.

These two factors combined—ineffective reverse thrust and increased ground speed—mean that the landing rollout is significantly longer at higher altitude airports compared to those at lower elevations.