THE NORTH ATLANTIC Systems Planning Group (NATSPG) plans to start preparations in December to pave the way for the introduction of a trial 1,000ft (300m) reduced vertical- separation minima (RVSM) across the Atlantic by January 1997.

The NATSPG, which includes all major North American and European regulatory authorities, will first verify the operability of systems being installed to allow the trial to take place. These consist of global-positioning-based monitoring systems and height-monitoring units, which are already in position on both sides of the Atlantic.

"In September 1996 we will be able to make a decision leading to an operational trial with a 1,000ft separation in January 1997," says ARINC oceanic separation programme manager, Kim Joyce.

The first operators' meetings to support the trial took place with Delta Airlines on 25 October and with United Airlines on 7 November. Delta plans to have at least two Boeing 767-300ERs fully cleared to take advantage of the lower minimum separation, while United is expected to have 767s and 777s cleared. The RVSM reduces the vertical separation from 2,000ft to 1,000ft between 29,000ft and 41,000ft for suitably equipped aircraft.

Daily airliner movements across the North Atlantic reached an all-time high of 850 earlier this year and are heading for 1,000 in 1996. Reducing vertical separation is the best way of increasing capacity, followed by horizontal-separation reduction in early 1999.

Speaking at the US Federal Aviation Administration's tenth Oceanic Airspace Conference in Los Angeles, Joyce said that RVSM implementation in the Pacific is "technically feasible" by 1998 to 2000, but she adds that "...various states will have to commit resources to it to achieve that target". The RVSM could be achieved within US airspace between 2000 and 2001, and within European airspace by 2001, she says.

The FAA, meanwhile, expects international agreement on a proposed reduced horizontal separation minima (RHSM) over the North Pacific by February 1996. Driven by improvements in communications, navigation, surveillance and air-traffic management, the lateral separation will be cut from 150km (80nm) to 90km. Longitudinal limits will be driven down based on a time-separation equal to creating a RHSM of around 90km.

See Feature, P28.

Source: Flight International