One pilot is assigned the task of accurate instrument flying while the other assesses the visual cues available at decision height, taking control to execute the landing once satisfied that the aircraft is in fact in the correct place and on a safe trajectory for a landing. The result was a major improvement in the safety of operations in low visibility, and as the concept clearly incorporates vast elements of what is now known as crew resource management (although predating this phrase by some three decades) it was expanded to encompass a far broader spectrum of operations than just low visibility.