Canadians say they’ll be ready for DRVSM’s debut

 - January 14, 2008, 11:07 AM

Just like Paul Revere’s midnight ride to warn of the incoming British, the Canadian Business Aviation Association is signaling to its troops that RVSM is coming. Those troops recently gathered at Toronto/Pearson Airport during a seminar sponsored by CBAA, Rockwell Collins and Mid-Canada Mod Center to discuss domestic reduced vertical separation minimums (DRVSM), scheduled to come into force in southern Canada airspace simultaneously with the U.S.’ nationwide implementation, currently planned for January 2005.

In October Nav Canada conducted a survey of all Canadian aircraft operators regarding their RVSM status and plans for their individual aircraft types. The survey, which had a 70-percent response from Canadian corporate operators,  showed that 46 percent were already RVSM approved; 36 percent plan to be approved by January 2005; 15 percent operate below FL 290; and the remaining 3 percent indicated they would retire their noncompliant aircraft before the start date. Approval here means compliance with the FAA’s AC 91 RVSM, Change I, which has been adopted as Canada’s official standard.

As of last April, Canada’s northern airspace, from 57.00N to the North Pole, has already been assigned as RVSM airspace, from FL 290 to FL 410 inclusive, with a transition zone between 52.00N and 57.00N. The transition zone will be eliminated when southern Canada and U.S. airspace become linked to identical RVSM altitude allocations over the North Atlantic and North Pacific, which have been in operation since 1997 and 2000, respectively.

Don MacKeighan of Nav Canada covered legislative and operational aspects and touched on general certification issues. MacKeighan, manager of RVSM programs at Nav Canada, represents Canada on RVSM activities at ICAO, Eurocontrol and FAA working groups. A second presentation by Ronald Redington of Rockwell Collins covered detailed avionics and certification requirements. Redington is the principal electrical engineer of air-data systems at Rockwell Collins.

MacKeighan described the background of RVSM, pointing out that the U.S. and southern Canada were now the major holdouts in the on-going transition to RVSM in the world’s most heavily used airspace. RVSM, he said, plays a key role in optimizing fuel burn, increasing airspace capacity–typically by more than 70 percent–and reducing delays. He predicted that once RVSM is fully implemented in North America, noncompliant aircraft filing for altitudes just below its “floor,” meaning FL 270/280, could end up at FL 230/240 in high-density airspace, with adverse fuel burn and corresponding range penalties.

As for the projected January 2005 implementation date, MacKeighan observed that, from his discussions with the FAA, any further change now seems unlikely, barring unexpected problems in ATC readiness. He believes the actual start date will be Jan. 20, 2005, in coordination with the promulgation cycle date of other non-RVSM procedural and operational changes.

Technical Aspects
Rockwell Collins’ Redington briefed attendees on the detailed technical aspects of RVSM certification. As many corporate flight departments now know, these are very exacting and extend through the aircraft’s basic pitot-static system and altimeters, air-data computers, autopilot (particularly its altitude hold), altitude-alerting system, transponder and even the condition of the aircraft’s skin around the pitot heads and static vents, mandatory preflight inspection of which is prescribed is in the airplane flight manual.

Redington described “group” RVSM certification: after five generally identically-equipped airplane types/models have been certified in flight tests, those specific types/ models are designated as a group, with the result that follow-on certifications in that group are much less costly, both in installation and downtime. However, new production aircraft are generally RVSM compliant when delivered from the factory and simply require the appropriate registration paperwork.

On the other hand, certification of the first five models of a given type can be costly, running up to $300,000 per airplane. And some types may never be economically certifiable, with the Boeing 707 and 727-100/200 and McDonnell Douglas DC-8s and early DC-9s falling into that category. MacKeighan mentioned that companies have, from time to time, announced the forthcoming availability of RVSM kits for various early, less popular types and models, but often find on further study that the small numbers still flying make it uneconomical.