US transition to reduced vertical separation minima was problem-free. The looming March deadline for installation of terrain awarenessmore challenging

As aircraft operators enjoyed a smooth transition on 20 January, when all Western Hemisphere countries converted to reduced vertical separation minima (RVSM). Overnight, the new regulations reduced vertical separation between aircraft from 2,000ft (600m) to 1,000ft, between flight levels 290 and 410 (29,000ft and 41,000ft).

Mirroring its smooth introduction in European airspace, the "non-event" of the transition to RVSM in US airspace was the result of substantial preparatory work by the US Federal Aviation Administration and industry. Whether this bodes well for the next, rapidly approaching regulatory hurdle – the 29 March deadline for installation of terrain awareness warning systems (TAWS) – remains to be seen.

While all airliners using the affected airspace were RVSM compliant by 20 January, the same was not true for the business jets and turboprops that routinely used these altitudes. Data indicates it was the more expensive and newer aircraft that were compliant from day one, with the older and less valuable aircraft being forced to use lower less fuel-efficient lower altitudes until their owners decide whether it is more cost-effective to upgrade their aircraft or replace them.

A similar divide is emerging the weeks running up to the TAWS deadline, with the larger and newer aircraft already compliant and the operators of older and smaller aircraft now rushing to meet the fast-approaching mandate, having held back from ordering equipment to see if prices would drop. Now they face a problem finding an avionics shop able to install the equipment before April at the earliest. The transition to TAWS promises to be more troublesome than the change to RVSM proved to be.

Minor glitches

The introduction of RVSM in US airspace "was a non-event," says Bob Lamond, director of air traffic services and infrastructure for the National Business Aviation Association (NBAA) in Washington DC. "There were a few very minor, inconsequential software glitches, but nobody reported any problems being cleared into RVSM altitudes."

A rumour had been circulating on the internet that pilots would not be cleared to enter RVSM airspace if their names and aircraft tail numbers did not appear on an FAA RVSM approvals database. This is the master list of approved aircraft and their aircrews that have been issued letters of authorisation (LOA) for RVSM operations. In the USA, RVSM clearance requires pilots to file an instrument flight rules flight plan with an FAA flight service station, or over the internet. Pilots must provide the aircraft's registration number and the numerical code for the aircraft type, followed by the suffix "/Q" which designates authorisation to fly in RVSM airspace.

While there has been some lag time – currently about 30 days – between issue of an LOA and the crew names and aircraft registration number showing up on the database, Lamond stresses it has not become an issue to date. "The ATC people did not check the database before allowing the aircraft into RVSM airspace," he says. "However, NBAA has been

told that, eventually, the FAA will cross-check it to see if those who got RVSM

clearance, upon implementation, actually had approval at the time. The FAA has not told us what penalties, or sanctions they might impose."

Corporate pilots who flew trips in the first week of US RVSM implementation agree with Lamond's assessment of the situation. "The only real difference I noticed was a change for FL350 [35,000ft] from a westbound to an eastbound altitude while flying over Denver," says Tom Philips, chief pilot for Raven Air, which operates a Dassault Falcon 200 for a private individual out of Missoula, Montana. "Denver's airspace has always been congested, and a bottleneck for transcontinental US traffic. But since RVSM was implemented, traffic in the area seemed to flow more smoothly. In fact, we noticed that no extensive vectoring was involved, despite the closer spacing of the aircraft. Before RVSM, we did."

Lynn Dreifus, a Falcon 20 pilot and manager, flight operations and training for TAG Aviation in White Plains, New York, called RVSM operations "a seamless transition". She says: "We were ready for this, and well ahead with respect to equipping the aircraft we manage for RVSM operations. We also started about a year ago, working with [Annapolis, Maryland-based] Assessment Compliance Group to develop a manual and training programme for domestic RVSM requirements and procedures."

According to Dreifus, the manual and training programme incorporated the few issues specific to the US and southern Canadian RVSM operations. One such issue, known as "mountain wave", concerns turbulence that mainly occurs over the Rocky Mountains. "Pilots have to be trained to deal with any contingencies that this phenomenon could create, such as the suspension of RVSM operating procedures in that airspace," she says.

Lessons learned

According to the FAA, much of the reason why US RVSM introduction went smoothly was the lessons learned from western Europe, where RVSM was established in January 2002. The FAA says that meetings with European representatives in the third quarter of 2002 and second quarter 2003 played a key role in designing US RVSM procedures and controller training.

For example, Eurocontrol air traffic controller training consisted of five to six, 20-30min simulator sessions incorporating complex handling and contingency procedures. Those procedures were validated by the time of the final session. "We used their training approach, but decided to go with longer, 30-45min simulator sessions," the FAA says.

Ron Swanda, interim president of the General Aviation Manufacturers Association (GAMA), credits the airframe manufacturers and modification shops for anticipating US RVSM early enough so that more aircraft could be equipped for it well in advance of implementation. He says that preparation really began with new production models.

"Over the last 10 years, most larger business jets have come out of the factory RVSM compliant, since they were more likely to fly over the North Atlantic, or parts of the Pacific that have had RVSM for a number of years," Swanda says. "But, with European RVSM implemented three years ago, any aircraft produced since then that could have potential European sales was also built RVSM compliant, even if it wasn't an exceptionally long range aircraft. In addition, many new turboprops have been produced RVSM-ready for the past five to seven years."

At the same time, says Swanda, retrofit kits for older business aircraft have become increasingly available. "For at least the past five years, all of the OEMs of RVSM-impacted aircraft have produced their own, or worked with outside vendors to supply kits for their aircraft. For that reason, GAMA believes that anyone who wants to qualify his aircraft and crews for RVSM can do so, even though in some cases it may be very pricey."

While Swanda takes nothing away from the efforts of the FAA, which prepared air traffic controllers and made some airspace realignments, he argues that the real work and most of the costs involved in the success of US RVSM should be credited to the manufacturers and repair stations. "They were the ones which developed the RVSM packages and made the increased hangar space available for the modifications. Because of this, people were prepared and everything went well," he says.

Still, not every US-registered aircraft was RVSM approved on the first day. According to a GAMA document using FAA and CSSI data, it was the more-costly airframes that tended to be RVSM compliant. Mark Grunewald, Gulfstream's national sales manager avionics, product support, says this trend holds true for the Gulfstream family. He says that 100% of Gulfstream IV and V models – including the G500 and G550 – meet RVSM equipment requirements, while 60% and 50%, respectively, of GIIs and the Westwind/Astra family (now supported by Gulfstream) are in compliance.

How much more the percentage of retrofit business on those two aircraft types will increase will depend on their resale values. "We are waiting for the Gulfstream IIs and Westwinds to change hands to see if the buyers feel it is economically feasible to comply with RVSM," says Grunewald. "RVSM is a significant modification with a cost that could equal a very high percentage of hull value, so there are a lot of operators in a ‘wait-and-see mode' with respect to a final decision on RVSM upgrades."

Upgrade work has been a lucrative business. Steve Elofson, team leader, aircraft modification sales for Lincoln, Nebraska-based Duncan Aviation, says that RVSM has accounted for "a large part" of the company's business over the past few years. "Most operators have been aware of the RVSM requirement and they have usually scheduled an RVSM upgrade, along with other maintenance events that would require some downtime," he says.

Elofson says recent RVSM business, especially over the past two years, has shifted away from operators of long-range jets that complied early with RVSM equipment requirements, toward those flying mostly within the USA, primarily the Citation, Hawker, Learjet and Westwind families. "RVSM installations will continue to account for a big part of our business throughout 2005. We believe that the business this year will come from operators who tried to fly at lower altitudes, but found that it wasn't worth it because of weather problems and traffic congestion."

Coupled with this, says Elofson, is the large number of smaller business jets available on the used aircraft market. "Most of those have not been brought into RVSM compliance, because they have been for sale for a while. In our experience, if these aircraft are sold, the new owner will probably upgrade to RVSM at that time."

TAWS next

Compliance with RVSM is not the only imminent operational issue facing operators. With the impending deadline to fit TAWS to all US-registered turbine-powered aircraft with six or more passenger seats, avionics shops are reporting near-panic buying. Gulfstream's Grunewald says customers are urged to book TAWS installations at the company's network of shops at least 30 days in advance.

"My phone has been ringing off the hook," Grunewald says. "Most of the requests are coming from operators who waited until the last minute to see if prices of the TAWS systems would decline.

But prices have remained constant." Duncan's Elofson saw requests for TAWS spike starting in January. "The demand has helped to use up the available

manpower we have for all avionics work," he says. "At our Lincoln, Nebraska facility we are advising customers that it will be

at least April before we can schedule a TAWS installation."

TAWS is an improved version of the ground proximity warning system (GPWS), which helps prevent controlled flight into terrain (CFIT). GPWS has been required all turbine-powered aircraft with at least 10 passenger seats in 1992, but in 2000 the FAA took the additional step of requiring the more-capable TAWS on all US-registered turbine-driven aircraft, extending to minimum down to six seats.

TAWS is available as either a Class A or Class B system. The more capable and expensive Class A, required on any aircraft operated for hire with 10 or more passenger seats, must present terrain information on a moving-map display, have input from a 2,500ft radio altimeter, and indicate imminent contact with the ground if the aircraft experiences loss of altitude after take-off; during excessive downward deviation from an ILS glideslope, or when not configured for landing. The system must automatically activate a voice "call-out" when the aircraft is 500ft above the ground or runway elevation.

Class B TAWS, which can be selected for aircraft of at least six seats and those not operating in air carrier service, does not require a moving-map display or radio altimeter input. However, it does need some visual warning system, such as an annunciator light. Warnings of excessive descent rates or altitude loss are required only upon take-off. It, too, includes the voice call-out at 500ft above ground or runway elevation level.

John Behrens, Honeywell's manager for enhanced ground proximity warning system business development for corporate aviation, says the manufacturer has delivered about 1,000 systems a month since February last year. That, he says, is up from 450 to 550 a month between March 2002 and February 2004. "The overwhelming demand is for the Class A TAWS," he says. For private operators "Class A systems account for about 85% of sales, even though there is a choice, and a considerable price differential." Behrens says a Class A TAWS ranges in price between $25,000 and $75,000, and a Class B system between $8,000 and $11,000.

"Normally, operators of newer, higher-end aircraft will go with the Class A TAWS, while the Class B system has found a niche in older, first-generation business jets. But normally, the higher the value of the avionics systems on board the aircraft, the more likely it is that the operator will choose a Class A TAWS," says Behrens.

NBAA says significant progress has been made to comply with the TAWS deadline. "We believe that the majority of the upper-end jets have been equipped with TAWS by now," says Eric Ramsdell, manager, safety and operations. "But

I think that most of the others will be compliant by the deadline. They are getting there."


Source: Flight International