Eurocontrol to test VLJ airspace access

 - June 2, 2008, 9:41 AM

Looking ahead to the introduction of very light jets (VLJs) into its airspace over the next 10 years, Eurocontrol has established two initiatives to understand the effect of VLJs in the ATC system. The first is the VLJ Integration Platform (VIP), a group of air navigation service providers (ANSPs), manufacturers, regulators and operators with a meeting planned for October 14 and 15. The second, a simulation project, will begin that same month.

The VIP includes most of Europe’s ANSPs and government regulatory bodies, manufacturers, airlines, the European Business Aviation Association (EBAA) and NetJets. Other interested parties have been encouraged to join. So far, the FAA has not participated in the group, but it is expected to join and present the U.S. position at the October meeting.

The second Eurocontrol initiative is a two-week simulation project covering the airspace of Central Europe, which will take place at the agency’s Research, Development and Simulation facility in Budapest, Hungary, in October.

Fitting into the System

VLJs have not yet started flying in European airspace in appreciable numbers, but current sales figures suggest that at least 500 will be operating in the continent’s densely packed airspace by 2010, and Eurocontrol wants to assess not only their near-term  impact but also the impact of the large number forecast to be added within the next 10 years.

Eurocontrol’s concern stems from two main issues: the expected performance of the VLJ fleet and the absence of full TCAS (or ACAS in ICAO-speak) in current models offered in the marketplace.

In terms of performance, departures are the main concern due to the VLJs’ lower speed and climb rate, which will probably necessitate dedicated departure sectors or corridors. But the study will also examine en route cruise at higher altitudes, say above FL300, where conflicts with faster airline jets could arise.

On the other hand, indications are that most European VLJ operations would be flown on relatively short legs, with cruise altitudes more likely to be around FL250 or below. The product of the simulations is expected to be the development of structured VLJ procedures for Europe, to avoid the use of differing routing clearances on a case-by-case basis.

The ACAS issue is more difficult to resolve. European airspace is now essentially an ACAS domain, where carriage is mandated for all civil aircraft weighing more than 12,500 pounds and having 12 or more seats flying in controlled airspace. VLJs meet neither requirement, but if they are required to carry ACAS, it could be prohibitively expensive for operators. According to one industry observer, such a mandate could “add a double-digit increase to the aircraft’s price, particularly in the case of a retrofit, plus extra avionics size and weight.”

In addition, the lack of ACAS in large numbers of aircraft entering the system in the future has raised concerns among European airlines, which regard the introduction of “non-cooperative” aircraft as reducing the safety factor of ACAS in their fleets.
Adding to their concern is the perception that at least some of the VLJs will be flown by pilots relatively inexperienced in high-density traffic and, for example, possibly unfamiliar with appropriate RA responses.

A less costly mandate for ADS-B in, with its associated cockpit display of proximate traffic that would provide VLJ pilots with a degree of enhanced situational awareness, has been suggested as an interim solution, but the possibility of a non-standard avoidance maneuver by the VLJ pilot in a close-quarters encounter is worrying to some.