We definitely must be talking about different sounds here. All the aircraft I have noticed making this brief groaning sound are flying the SID's and still below 6000ft.
It is definitely not the spoilers or a config change.. Not quite sure how some of you on the ground seem the know the flight crew are deploying the spoilers? X ray vision?
I'm still convinced it is some weird sound reflection of certain terrain, was hoping for a definitive answer from someone.
Btw, I think someone mentioned a lightsaber, a light saber turning off is exactly how it sounds to me, except the sound is much deeper.
Very strange and random, hense my curiosity.
Last edited by NOLAND3; 5th September 2012 at 19:56.