Why does the Sound of an Aircraft Engine change on Takeoff?

Added: 2026-06-02

[00:00:00]Ever wondered why on takeoff, the pilot applies the power in two distinct steps?

[00:00:04]Well, the answer is that it's primarily a safety procedure to ensure the airplane's power plants are responding properly and symmetrically, as well as being good engine management practice.

[00:00:13]The first pitch increases when the engine thrust levers are advanced about 50% of the engine's maximum power.

[00:00:21]It gives the pilots a chance to check that all the dials are good to go. Only when both sky gods confirm that the engines are stabilized, do you hear the second pitch change? That's 30 seconds on takeoff power application.