FAA discusses future of WAAS and LAAS at safety forum

 - December 18, 2007, 7:08 AM

At the FAA’s September International Aviation Safety Forum near Washington, the agency included a discussion session entitled “WAAS or LAAS, which is it?” An explanatory note in the agenda stated that “The FAA is investing in both, but industry experts are divided over the safety issues and benefits. What are the costs and benefits of WAAS? LAAS? Which one should we be investing in?”

FAA ATO COO Russell Chew moderated the session, which included input from senior operations executives from Southwest Airlines, ATA Airlines, FedEx and Boeing, as well as AOPA president Phil Boyer. While LAAS is still in the research and development stage, WAAS is already in routine use as an en route and terminal GPS enhancement. Chew noted that the agency had a continuing commitment to LAAS, but was not prepared to say when the currently sidetracked program might be restarted.

The major LAAS issue that Chew and his staff must resolve is its cost/benefit equation. If the FAA invests substantial funds–some say well over $1 billion–to extricate LAAS from its research holding pattern and move it into full-scale development, production and nationwide implementation, will it pay off?

In March, Dan Salvano, FAA director of navigation programs, told policy makers of the Civil GPS Service Interface Committee that agency officials estimated that LAAS costs would exceed the system’s benefits, an unusual forecast from an organization renowned for budgetary optimism about its future major programs.

The crux of the cost/benefit issue centers on FAA’s Category I strategy. As one official put it, “We’re really in a Catch 22 situation here. WAAS is looking better than anyone expected. We now know that 250-foot LPV [localizer precision with vertical guidance] approaches are achievable, which is why we are now going for WAAS Category I, which is much cheaper than LAAS. And with the WAAS expansion, we’ll be able to provide that across the continental U.S. and most of Alaska. We also know that relatively few operators will be interested in switching from ILS Category I to LAAS Category I for no extra benefit. Most will switch only when we can offer nationwide Category II/III LAAS.”

Cost/Benefit Equation
Currently, IBM Global Services Company is conducting a LAAS benefits analysis for the FAA; the final report was due to be delivered last month. AIN obtained a preliminary copy of the analysis, which predicts the user savings achievable from LAAS over a 20-year period at the nation’s 120 busiest airports.

The report breaks these savings down into those achievable in various phases of flight. The 20-year period would commence with the initial introduction of LAAS Category I in 2009, with the initial introduction of LAAS Category II/III in 2013. Flight-phase benefits were forecast to accrue from:

• lower minimums from straight-in versus nonprecision approaches

• improved takeoff guidance in low visibility

• improved ability to fly complex approach procedures

• elimination of ILS critical areas

• increased capacity from closely spaced parallel approaches.

The preliminary analysis predicted that the total savings across the user community over 20 years would amount to just under $2 billion, divided roughly equally between direct operating and passenger-time-saving costs. As might be expected, the bulk of these savings– roughly $1.8 billion–would be achieved by the major and regional airlines, with corporate jet operators predicted to save $92 million.

The ability to conduct straight-in approaches to all 720 runways of the 120 airports studied yielded around $1.5 billion in benefits, versus $500 million for the savings during other flight phases. But of those phases, takeoff guidance was acknowledged to be strictly a HUD/Category III activity; complex procedures and parallel runway guidance were recognized as achievable by other techniques, such as ADS-B or RNP, and the elimination of ILS-critical areas would be realized only when there were no more ILS-equipped aircraft.

The 97-page analysis was, as befits IBM, replete with projections and data breakdowns of all types, some of which were hair-splittingly precise. For example, it was proposed that under reduced capacity conditions at New York JFK International, LAAS would reduce delays by three hundredths of a minute per aircraft. Multiplying this by the number of flights per user group would give the total number of minutes gained by each group. Multiplying that total by the cost of a minute of delay yields the group’s cost savings at JFK.

The analysis then factored in the likelihood that LAAS would be combined with other technologies to achieve this improvement, and divided the total by two. After that, researchers applied a “downstream effects” factor of 1.5 for disruptions, with the result that the final estimated total direct operating cost saving from LAAS over its 20 years of service at JFK is $225,000. Unquestionably, the logic is impeccable. One is only left to wonder whether it applies in the real world.

The researchers also appeared to treat all 720 runways as equal from the perspective of user demand. An FAA official said, “That doesn’t make sense. All airports have designated bad-weather runways where we’ve installed ILS. The others either aren’t suitable for Category I or the expense of installing approach and runway lighting to support a Category I ILS wouldn’t pay for the amount of use they’d see.

“WAAS with LPV will be more than adequate for those, and it will provide a straight-in approach. But if IBM’s $2 billion figure is correct, and few airlines want Category I LAAS, why should we wait until 2013 for Category II/III LAAS to get those benefits when we could upgrade most of our ILSes to Category II/III and get them today, as the Europeans have done?”

The researchers did recognize the potential of WAAS to eat into their estimates and posited two scenarios. One assumed no WAAS aircraft installations, and the other assumed all aircraft would carry WAAS as well as LAAS. The above forecast benefits assume no aircraft are equipped with WAAS; in the all-WAAS case, the benefits were reduced by roughly one-third, from which researchers concluded that the actual benefits would lie somewhere in between.

With the LAAS benefits analysis in hand, the FAA will need an equally thorough assessment of the 20-year costs to operators and the agency of developing, acquiring, installing, certifying and maintaining the avionics and LAAS ground stations, to complete the other side of the cost/benefit equation.

It is understood that the agency has yet to launch a detailed cost analysis comparable to the IBM benefits study, although this would appear to be essential before the agency decides when–or whether–to restart the LAAS program.