The FAA’s sweeping proposal to implement domestic reduced vertical separation minimums (DRVSM) in the U.S. starting in December 2004 drew sharp reproves last month from NBAA, which said business aviation was double-crossed by the agency after an earlier, less ambitious proposal calling for a phased implementation schedule was abruptly scrapped in deference to a recommendation by air traffic controllers.

Several general aviation trade groups, led by NBAA, criticized the agency for its decision to apply the restrictions in airspace from FL 290 to FL 410 in a single step rather than phasing in DRVSM over a number of years. When implemented, DRVSM will reduce separation between airplanes flying at higher altitudes from the current 2,000-ft minimum to 1,000 ft. Costly upgrades to avionics and flight controls in the majority of cases will be required before aircraft will be permitted to fly in affected airspace. According to the latest estimates, more than 7,000 business aircraft still need to undergo such modifications between now and late 2004, insufficient time to ensure a smooth transition to DRVSM, experts claim.

The FAA originally intended to introduce DRVSM in two steps, the first stage of which would have included the flight levels from FL 350 to FL 390. The second stage, planned to take effect in 2005 or 2006, would have expanded DRVSM down to FL 290 and up to FL 410, ensuring that business aircraft operators who were experiencing difficulty gaining DRVSM approval by late 2004 would not be forced to fly at the far less fuel-efficient altitudes below FL 290.

The plan had the full support of GA trade groups and the airlines, all of whom believed phased implementation of DRVSM would help ease the financial burden to operators. Then, say those familiar with the rulemaking process, in early 2000 the FAA reversed course and announced it intended to introduce DRVSM in a single stage beginning in December 2004. NBAA places blame for the shift in policy on the National Air Traffic Controllers Association (Natca), the labor union representing more than 15,000 of the nation’s controllers.

“The FAA’s original plan to roll out DRVSM in two phases had the full concurrence of the aviation community,” said Bob Lamond, NBAA’s head of air traffic services. “Even
the airlines supported a segmented implementation schedule. What changed were the protests from Natca leaders, who said, ‘We don’t care when you do it, just do it all at once.’”

Based on a series of simulations run at the FAA Technical Center in Atlantic City, N.J., last October, controllers decided it would be difficult to introduce DRVSM in steps. Steve Entis, Natca’s head of RVSM programs, said a phased implementation schedule as envisioned by GA trade groups would have wreaked havoc on the system by forcing controllers to switch back and forth between 2,000- and 1,000-ft separation standards in the higher flight levels.

“As a result of these tests we decided phased implementation would have increased controller workload and the potential for error, and quite frankly we didn’t see the benefit,” said Entis. “Ninety percent of the traffic in that airspace is airline, and just 10 percent general aviation. Does it really make sense to hold up benefits for 90 percent to appease 10 percent?”

When the economy began to slow last spring, the airlines told the FAA they could live with one-step implementation of DRVSM because they planned to park their older airplanes, which were flying less profitable routes. The FAA, estimating DRVSM would provide about $5.8 billion in fuel savings to airlines from 2004 to 2018, sided with Natca and the Air Transport Association, deciding to reject the notion of a phased-in implementation schedule.

“An internal decision within the FAA was made last fall to implement DRVSM in one step,” said Lamond. “The FAA was aware of our opposition, it was aware of significant concerns we had about the ability of FSDOs to grant operator approvals. It was aware that not all aircraft were even capable of gaining certification because the avionics at that time did not exist. And despite all of this, it went ahead anyway.”

Lamond said NBAA clearly supports DRVSM implementation and other airspace initiatives, and that the association realizes the importance of applying technology in ways that will benefit all segments of aviation. However, he said, NBAA’s view–and one that is shared broadly by other GA trade groups–is that phased introduction of DRVSM is needed to give operators time to comply. A significant concern, said Lamond, is the FSDO approval process, described by some business aircraft operators as a melee of seemingly endless paperwork and a hodgepodge of rules that can vary widely from one field office to the next.

“The FSDO verification process is a very real problem,” said Lamond. “Even if manufacturers could pull a rabbit out of their hats and perform a miracle in getting avionics certified in time, the approval process in many instances has been a nightmare for our members.” He said the FAA has told NBAA it agrees with this assessment and is taking steps to remedy the problem.

A small but vocal group of business aircraft operators, meanwhile, has been asking why DRVSM is needed in the first place. After all, these pilots argue, vertical separation in the airspace below FL 290 is already 1,000 ft, and closer to the ground where VFR traffic mixes with IFR aircraft it is a mere 500 ft. To this argument, Lamond pointed to reams of scientifically accepted data that spells out why more accurate height-keeping instrumentation is needed at FL 290 and above.

“Most of our members understand very well why technology initiatives such as DRVSM are needed,” said Lamond. “In fact, most of the pilots I’ve spoken with are bewildered by the fact that other professional pilots can’t understand this as well.”

In addition to NBAA, others voicing opposition to the DRVSM proposal, issued on May 10, included AOPA, the Aircraft Electronics Association, the General Aviation Manufacturers Association and the National Air Transportation Association. All are expected to submit formal comments to the FAA by August 8, the official close of the NPRM comment period.