I live directly under the flight path into Sky Harbor. I notice during the day that they drop flaps right over my house and the noise is very noticeable( I don’t mind it)But in the evening I never hear them drop flaps. Can anyone tell me why.
I’m not sure you’re hearing the flaps. In a quiet hangar you can hear them, but with the air flowing past the aircraft and the engine noise. Also the speed at which they’re travelling and the time it takes the flaps to come down the sound would be constant.
What you’re more than likely hearing is the increase in power from the engines that normally corresponds with the deployment of flaps.
OK this could be but why don’t I hear it at night
It could be that the winds change enough in the evening that the sound is “pushed away” from your direction.
Possibly because they’re prudently setting up for the landing (deploying flaps, gear, etc.) earlier in the approach than during daylight.