ABSTRACT
Introduction In 1997 a study was launched to determine whether the then-current aircraft separation minima between aircraft in the Open Flight Information Region (OFIR: class F and G airspace, UK) receiving a Radar Advisory Service could be reduced safely, in order to help optimize controller workload. In particular, it was seen as desirable to reduce the lateral and vertical separation minima from 5nm and 5000 feet to 3nm and 3000 feet respectively. The four-year study comprised a number of inter-related elements, but Human Factors played a dominant role throughout. This chapter explains the context and motivation behind the study, the Human Factors approaches that were used, the decision-making rationale, and the arrangements for the safe introduction of the new vertical separation minima in the UK OFIR. Background This first section explains relevant aspects of the UK airspace, the air traffic service in the Open Flight Information Region, and the motivation that existed for a reduction in separation minima, which led to the study taking place. UK Airspace Classifications In the UK, the airspace within which aircraft operate is classified according to the type of service provided to pilots by Air Traffic Control (ATC) and the ratings required of pilots and avionics systems in order to operate in that airspace. There are six classes of airspace in the UK, namely Classes A, B, D, E, F, and G. The International Civil Aviation Organization (ICAO) also defines Class C airspace, but there is no Class C airspace in the UK.
