BOAC,. .. .Quite right. When flying into unfamiliar FIRs, I review the appropriate procedures coming up to the boundary, and have the charts to hand.. .. .A couple of points: First, be wary of making that turn to clear the airway if it will take you into a danger area or military training area or what-have-you, second, I would think that in a busy CTA (Daventry, for example), a ninety degree turn without instruction to do so could put you well and truly in the brown stuff.