Eurocontrol is to assess the potential impact on European airspace of a rapidly increasing population of very light jets, following concerns over the effect their performance could have on traffic flow.

About 440 VLJs are on order from customers intending to use them in Europe and nearly half of these are expected to be delivered by the end of 2010, says Eurocontrol. It estimates that 100 aircraft will enter service each year and 700 will be operating by 2015.

The agency has set up a new forum, the European VLJs Integration Platform, which aims to bring together VLJ manufacturers and operators to discuss mechanisms and strategies to integrate the jets into the European air traffic management system.

Eurocontrol also intends to extract enough information about VLJ operations to carry out simulations to examine the effects of their introduction and proliferation.

"Growth of VLJs adds a significant extra dimension to the complexity of air traffic in Europe," says Eurocontrol's deputy director of air traffic management strategies, Alex Hendriks.

He says the different performance characteristics of VLJs compared with regular commercial aircraft, particularly in the departure and en-route phases of flight, are likely to have a "considerable impact" on the air transport network.

Several types of VLJ are already available or under development, among them the Cessna Citation Mustang - scheduled to enter commercial service in Europe early this month - the Eclipse 500, Adam A700 and Embraer Phenom 100.

These VLJs are likely to create problems because they will typically operate between flight levels 330 and 350 - within the most heavily populated band of European cruise altitudes - but will travel at speeds of only 340-380kt (630-700km/h), about 20% slower than larger transports.

There are also concerns over a broad disparity between the climb rates of VLJs against those of regular jets. Eurocontrol's airspace network planning chief, Joe Sultana, told a VLJ workshop last year that aircraft performance differences, in both en-route and terminal airspace, could lead to a significant impact on controller workload. He also warned that wake vortex could pose a hazard if VLJs needed to climb or descend through occupied flight levels.

Possible strategies to cope with VLJs could include airspace redesign, with dedicated departure and arrival patterns, as well as parallel offset procedures.

From next year, VLJs could be contributing an additional 200-300 flights a day to European traffic and this figure is expected to reach 1,000 flights a day by the middle of the next decade. "We'll also need to assess the technical requirements for on-board systems," says Hendriks.

This will include an analysis of whether VLJs should be required to carry traffic collision-avoidance equipment. European airspace regulations only mandate carriage of such systems by civil aircraft with a maximum take-off weight of over 5,700kg (12,550lb) - twice that of a typical VLJ - or with more than 19 seats.

Eurocontrol also says there "may be difficulties in adapting certain VLJs' avionics systems to comply with particular navigation requirements".

Source: Flight International