EC plan would shift money from navaids to avionics

 - January 29, 2009, 7:57 AM

Eurocontrol might ask the European Commission to use some of the money expected to be saved by the planned decommissioning of VOR and NDB beacons to sponsor the development of avionics that would enable general aviation aircraft to operate in the sort of controlled airspace envisioned by the single European sky air traffic management (ATM) research (Sesar) program.

The idea emerged at a recent Eurocontrol workshop in Brussels attended by more than 100 regulators, operators, representatives of pilot organizations, airframers and equipment manufacturers.

The navigation strategy endorsed by the inter-governmental European Civil Aviation Conference (ECAC) in May stipulates the global navigation satellite system (GNSS) as the primary means of navigation. The problem for general aviation is that aircraft will require a back-up, and neither of the two proposed back-up systems–DME/DME and inertial reference systems (IRS)–is available, affordable or practical for most GA aircraft.

High-end business jets are among the best equipped of all airplanes and should have no problem. But the only airplanes in Cessna’s extensive range to sport an IRS are the Citation X and in-development Columbus; for the smaller Citations “it’s hard to justify the cost and weight,” said Lance Raile, the airframer’s technology director.

The problem is even more acute for very light jets. Cessna’s Mustang has a single DME channel, but Raile said a scanning DME “could be difficult in terms of cost and weight, and we’re delivering Mustangs now so it would put a burden on operators.”

Frank Remmerswaal is managing director of Amsterdam-based Etirc Aviation, which is the majority shareholder in Eclipse Aviation. He said Eclipse had reluctantly added Garmin GPS 400Ws to the 500 panel to gain a European type certificate, but there is “virtually no real estate for additional avionics” and he would like to see a software rather than a hardware solution.

GA avionics specialist Garmin has more than 100,000 GNS 430/530 units in service, not to mention more than 5,000 G1000 glass cockpits and 20,000-plus products capable of using satellite-based augmentation systems such as the wide-area augmentation system (WAAS). But it does not make scanning DMEs, which are available from only a few manufacturers at an estimated cost of between $17,000 and $22,000, staff engineer Clay Barber told the workshop.

Certified inertial systems based on ring laser gyros cost even more–approximately $210,000 to $293,000 at list prices. And while micro electro-mechanical systems (MEMS) technology promises lower costs, the least expensive MEMS devices require GNSS aiding and lose their stability within a minute. Higher-grade MEMS gyros might provide adequate performance, but the cost of a position sensor incorporating one would probably be comparable to that of scanning DME.

In any case, Barber added, existing panel-mount standalone GNSS equipment is not designed to support a multi-sensor flight management system (FMS) solution, and Garmin’s integrated avionic systems currently do not support such a solution.

Okko Bleeker, European R&D director for Rockwell Collins, suggested that avionics packages designed for unmanned air systems (UAS) might provide a basis for the necessary navigation capability. They typically cost a fraction of the price of avionics in piloted aircraft. While Bleeker declined to specify the size of the fraction, he said the cost of the avionics must be consistent with the price of the airplane.

A VLJ, for example, can bear a cost of $30,000 to $40,000 for the avionics package: UAS air vehicles, on the other hand, typically cost far less than a VLJ and systems are priced accordingly.

Lex Hendriks, Eurocontrol deputy director of ATM strategies and the workshop’s chairman, emphasized that aircraft flying VFR-only or outside controlled airspace are not affected. He added that automatic dependent surveillance-broadcast (ADS-B) would not solve the problem because its dependence on position information from aircraft means that if the aircraft navigation solution is downgraded surveillance is downgraded as well. Loran might work, but without an on-board back-up, he added, “the back-up is ATC workload.”    

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