NATA has asked the FAA for a longer phase-in period for implementing domestic reduced vertical separation minimums (DRVSM) in 2004 due to economic and operational considerations.

 In a letter to FAA Administrator Jane Garvey, NATA v-p Jeb Burnside said the association is chiefly concerned that any FAA cost-benefit analyses employing pre-September 2001 traffic projections may no longer be appropriate. “NATA believes the FAA should carefully consider the effect of domestic RVSM at FL 350 to 390 on the current fleet of turbine aircraft,” he wrote.

Although most Part 135 on-demand air charter operators conducting international operations have already obtained RVSM approval, NATA said there are many turbine aircraft regularly operating in the future DRVSM airspace that are not RVSM-compliant. It expressed additional concern that insufficient repair station capacity exists to meet the demand in such a short timeframe.

NATA has estimated RVSM modification costs for older turbine-powered aircraft of $200,000 to $300,000. Such a figure could represent as much as half the value of the aircraft, NATA said, and some aircraft may simply be unable to meet the tolerances required for approval.

According to NATA, these certification costs and the possibility that, after the costs are incurred, a specific aircraft may still be unable to obtain certification mean that operators could be forced to retire aircraft early. This would impose a significant economic burden on operators–mostly small businesses–still recovering from the effects of September 11, the association warned.