May 13, 2002
FAA Draft Rule Sets Plans For Domestic RVSM By 2005

FAA has finalized a draft rule proposing a one-step transition to Domestic reduced vertical separation minimum (DRVSM) in December 2004. The notice of proposed rulemaking, slated for publication tomorrow, will have a 90-day comment period.

The move would add six flight levels between 29,000 feet (FL290) and FL410 by reducing required vertical separation between planes to 1,000 feet from the current 2,000 feet. The capacity gain would mean more preferential routings for flights, more options for controllers when faced with conflicting flight paths and, ultimately, a more efficient National Airspace System (NAS). FAA calculates that DRVSM's benefits would save operators $5.8 billion in fuel costs over 15 years, including $371 million in the first year of operations.

Aircraft must be equipped with avionics that meet certain criteria, such as maintaining an assigned altitude within a specific margin, to be RVSM-capable. Aircraft that aren't RVSM-certified won't be allowed to cruise in U.S. DRVSM, making it "exclusionary" airspace. The only exceptions are military and other government aircraft, some of which can't add RVSM avionics. Non-equipped aircraft will be allowed to transition through the airspace. Because the airspace will be exclusionary, many in the general aviation community opposed shifting all of the airspace over to DRVSM in one step to give GA operators more time to upgrade. They favored the approach taken over some oceanic airspace, in which smaller bands were phased in until the entire 12,000-foot block was converted. "We're not entirely happy that airspace won't be phased in, but we think we can make that work, said Ron Swanda, VP-operations for the General Aviation Manufacturers Association.

The more pressing concern, he said, is ensuring FAA can meet the certification crunch as operators seek to take advantage of the new airspace by upgrading their aircraft. FAA keeps a database of RVSM-certified aircraft. So far, about 3,600 planes, including 1,600 airliners, can use RVSM and DRVSM airspace, said Roy Grimes, FAA's RVSM program leader. FAA data show that about 13,500 planes use airspace between FL290 and FL410, he said. Just how many of the 10,000-odd planes that aren't ready for RVSM will seek certification is not clear.

FAA's concern isn't airframes, it's operations. FAA operator surveys indicate that, based on the existing RVSM-certified planes or plans to get aircraft upgraded, 90-95% of the flights that those 13,500 planes will make in December 2004 will be DRVSM flights. The remainder, including operations by planes that may seek DRVSM certification in the future, can be handled at FL280 and below or FL430 and above, depending on a plane's capabilities, Grimes said. "If we found that 70% or 75% of the flights would be RVSM, accommodating the remainder would have meant a huge disruption to the system," he noted.

Back to Articles