Sideslipping Heavies
Presume the questioner wants to know whether sideslippng a heavy is a useful manoeuvre.
Effective flaps and high lift devices which also substantially increase drag have long since negated any usefulness from sideslipping to increase an angle of descent.
So there is a lot of consideration in design to keep sideslipping to a minimum. It increases drag and particularly with swept wings introduces strong rolling forces.
Maximum sideslipping for a multi engined aircraft usually occurs at Vmca when the pilot will have maximum rudder input that he can provide to offset asymmetric thrust.
There may still be the odd aircraft around which suffers from rudder overbalance. This is nasty and in the worst case will cause the rudder to lock hard over. TPs approach that area very carefully.