GD&L,
you must have misunderstood my post, or better, I was too elliptic. Não da is indeed very general and means I cant do it, unable to achieve, to do what you ask me. Because it is so general, it can t be interpreted to mean that a TL was stuck. It just meant, I can t decelerate. As you rightly said, the next question, why?, was never asked...
And I agree too that the decelera could mean either... but can any pilot tell us whether it is used as a synonime for 'retard'? I still think it was used in its general meaning of slow down. The deacelera might just be used because it is so close to the english 'decel' used in the ac logic.