FAA spokesman Greg Martin defended the action. "The primary intent of this notice is to be a wake-up call to the facilities, to take a close look at taxi into position and hold, and see if they need it," he told AVweb on Tuesday. "And if they don't need it, don't use it. ...This is due to a recent spate of operational errors and subsequent loss of separation." He added that pilots will not be affected. They will know whether the procedure is available or not because they will be talking to the controllers. "Dallas has already reviewed their procedures and verified that they need [tiph], so they will continue to use it," he said. "As will most facilities that have shown a significant increase in volume." Martin added that there is no strict structure in place for the operational review.