Why does my airliner turn the engines way down about 3 minutes after takeoff?

I fly a lot on business, and I’ve always noticed this on takeoff; the engines spool way, way up and we go blasting off the runway. Then, about two to five minutes in, at altitude but still climbing, and after the flaps/wing extenders have been retracted, the engines spool way down. Then they go back up, not as high as before though.

I can understand why you’d bring the engines back a bit when you want to level off, but why drop them way down, then raise them again?

Noise abatement procedures?

How long after throttling down do they start bringing them up again? If it’s right away, it might be that they pulled way back to loose a bunch of thrust they didn’t need, and then were slowly pushing the engines back up to get the kind of thrust they wanted. I’m not sure how turbofans work, but I’ve heard of turbine engines having a lag between a throttle adjustment and the engines responding, so this could be due to that (assuming I wasn’t just plain told wrong about the lag)

You’re referring to Toronto Pearson, right? mks57 has it - noise abatement procedures are in effect there. [The Greater Toronto Airport Authority](www.gtaa.com/documents/community/ noise_management/managingnoise.pdf) says: