Winglet 21 are you Chtr or RPT?, anyway RPT Operators will have their NOISE ABATEMENT procedures in their S.O.P's and generally they will run along the lines of 10.4 Jepp reguirements. These of course consider all engines operating [naturally], the only restriction you would have to check is the bypass ratio of your A/C engines. I think its > 3.5.1 to meet Jepp 10.4. It's the crackle factor that upsets the earthlings!
Happy Flying
[This message has been edited by Windshear (edited 19 January 1999).]