Graham Warwick/ATLANTA
CORPORATE-AIRCRAFT operators are hoping for a significant delay to the scheduled 1 January 1997, introduction of reduced vertical-separation minima (RVSM) on routes over the North Atlantic. The move to increase the capacity of Atlantic airspace by halving the vertical separation between aircraft to 1,000ft (300m) will entail expensive modifications to many business aircraft.
Proposed by the International Civil Aviation Organisation (ICAO), and welcomed by airlines, the RVSM has taken corporate operators by surprise, admits Dave Pleskac, of US modification-specialist Duncan Aviation. While business aircraft account for only 3-4% of transatlantic traffic, compared with airlines far more airframe types are affected, he says.
The ICAO is expected to announce a delay and possibly the phased introduction of the RVSM, with certain altitudes reserved for suitably equipped aircraft, but the extent of the schedule relief is not yet clear, Pleskac says. A three-month delay would have no effect on corporate operators, he says, but extending the deadline by a year "..would provide breathing room".
RVSM rules call for increased altimeter accuracy, with the 200ft altitude tolerance requiring dual digital air-data computers. "Some aircraft have no air-data computer at all," says Pleskac. Fitting two computers will cost around $200,000, he estimates. Certification of the installation could cost another $50,000.
The new rules also place a 130ft tolerance on the autopilot's ability to hold altitude, which may require modification of the older analogue systems installed in some aircraft, Pleskac says.
Manufacturers are already developing service bulletins and certification-data packages to allow modification of those major business-aircraft types used for transatlantic flights. These include, the Canadair Challenger, Dassault Falcon and Gulfstream, but many aircraft now in use, will not be covered by the manufacturers, he says. These "non-group" aircraft include short-range types only occasionally used for transatlantic trips.
Supplemental type-certification of aircraft not covered by service bulletins will be "no easy task", says Pleskac. Operators of non-group aircraft wanting continued access to Atlantic airspace are faced with the choice of paying a substantial sum to upgrade and certificate their aircraft or of switching to a type for which the manufacturer provides RVSM support, he says.
Dassault believes that it is the first business-jet manufacturer to submit an RVSM certification data-package to the US Federal Aviation Administration. Data for the Falcon 2000 was submitted for approval in March, with data for the Falcon 900 and 50 to follow. Gulfstream is leading US National Business Aircraft Association efforts on RVSM compliance. Falcons and Gulfstreams together make up almost 60% of the business jets on transatlantic routes.
Source: Flight International
