The GPS approach is out, and the Rnav approach is in. That’s because many pilots tend to think of GPS as a land-based navaid like a VOR, NDB or as a part of an ILS, and experts believe that thinking is misleading. More precisely, it’s the FMS in the airplane that allows the actual instrument approach to be flown. GPS provides only the precise positioning information needed to carry it all off by listening in to some of the 24 GPS satellites orbiting nearly 11,000 miles above the Earth.
Under the best conditions, a pure GPS-Rnav approach can provide an MDA as low as 250 feet agl and visibility minimums down to one mile without the use of ground-based navaids and without the line-of-sight restrictions of earlier Rnav systems, if an airport has a certified approach, that is.
The advent of GPS has made it possible for airports never before served by an IFR approach to have one. An FAA spokesman said the agency has been hard at work certifying new approaches over the past few years, many as overlays to existing procedures and some as stand-alone approaches. “In fact, 559 approaches were certified in the United States in 2003 alone, with 510 of those being GPS,” the spokesman said. In 2002 the FAA certified 618 GPS approaches.
According to Dave Madison, FAA assistant division manager for terminal and en route procedures, one of the problems the FAA faces is that “the manufacturers are still getting the boxes into the airplanes. We must decide which approaches to build that will offer users the most benefit. We plan to publish about 400 approaches in 2004, of which 275 will be for [airports without scheduled airline service].”
There are currently more than 3,500 GPS-Rnav approaches in the U.S., compared with 2,700 VOR approaches, 1,700 NDB approaches and more than 1,000 ILSs. Tom Accardi, FAA program director for aviation systems standards (AVN) in Oklahoma City, detailed some of the workload complexity of approach certification and maintenance issues his group oversees. “In 1995 our group regularly maintained some 8,500 instrument approaches around the U.S. Today that number has risen to 14,000. And we’re working with only 10 percent of the staff we had in 1995.”
Despite the agency’s workload, some people are questioning the FAA’s priorities.
According to the instrument approach production schedule the agency publishes on its Web site, the vast majority of approaches initially published were to overlay existing approaches at Part 139 airports (those with airline service). “Interestingly,” one user said, “the business-jet guys are the ones who really lead the industry with the equipment necessary to fly the newest GPS approaches, yet the FAA has spent millions of dollars certifying an overlay approach to the ILS at O’Hare, for example, that no one will ever use.”
Madison responded, “The flight procedures office schedule is prioritized based on risk assessment by the FAA’s commercial aviation safety team [CAST] first for Part 139, then those with runways equal to or greater than 5,000 feet and finally paved runways less than 5,000 feet.” Accardi said, “High-risk runways were certified first based on NTSB recommendations that were worked out with the airline industry.” Aspen airport director Jim Elwood added, “AVN takes approach certification requests as they come in the door. You must take a number. GPS has created a tremendous backlog for approach certification.”
Moving an instrument approach from concept to the first landing can be a long, often frustrating process, according to some users. But Madison added, “The process of certifying an approach is collaborative. We certainly don’t do this alone, but work with industry and individual users. We sometimes will often look at approach certification based on a congressional request.” One surprising roadblock to new approach certification can be airport managers, Accardi said. “Some managers are concerned that a new approach means more traffic and increased liability, and they simply say no thanks.”
The certification process can begin in two ways. One is to fill out the first-request forms for an approach with the FAA and wait what could be many years until the number is called. An online version of the application is available under the “How to Get an IFR Procedure” button at www.avn.faa.gov. Madison said he could not recall an approach not being certified due to budget constraints, but moving through the traditional FAA system means some approaches aren’t due to be certified for five years, according to the agency production schedule. Accardi said the FAA does reprioritize the certification schedule every six months.
While most anyone could walk the paperwork through the proper FAA channels to certification, if they understood the system, there is a second method to speed the process along. This entails hiring a consultant such as Jeppesen to handle much of the initial paperwork for a fee. The cost is moderate and lines up pretty closely with what the FAA will charge to develop an approach from scratch.
The cost of developing a GPS-Rnav approach is measured in much more than raw dollars. What is the value of a company’s ability to land a Global Express at an airport 25 miles closer to the destination or complete a mission when the weather is well below the minimums for the current nonprecision approach? Daytona Beach Airport, Fla. director of business development Stephen Cooke spoke to that airport’s recent inauguration of a number of new GPS approaches. “These new GPS arrivals significantly accent the few approaches we already had in place, with improved flexibility. We now have approaches to Runways 25 Left and Right, 7 Left and Right, as well as Runways 34 and 16. This certainly enhances our users’ ability to get into and out of Daytona more quickly when the weather is poor.” Daytona Beach Airport sees some 365,000 landings and takeoffs annually.
Most Start at the FAA
While companies such as Jeppesen can certainly speed approach development through the system, whether the approach is publicly funded through the FAA or will be reimbursed by a private organization, AIN learned that a sizable number of airports defer to the FAA to begin the certification process, except when an IFR approach is needed for some special reason, as was the new localizer approach recently installed in Aspen, Colo., where a GIII crashed in 2001 when attempting to land while on the VOR approach to Runway 15.
Aspen Airport director Jim Elwood said the work to build the airport’s new localizer approach began when “some people I knew at the FAA told me the enhancement in technology today would really allow this to happen here. Historically, localizers in mountainous terrain can have odd reflections that often make them unstable.” Aspen users gathered together to support Elwood during the certification process but wanted to see the approach installed quickly. The Aspen community opted to reimburse the FAA for the $500,000 development costs. Currently, the Aspen localizer approach is still considered a special procedure available only to a select group of users who meet minimum aircraft equipment and crew-training requirements. It is expected the localizer approach will transition to a public domain approach by this spring. The new approach brings aircraft to an MDA only 900 feet above the ground, considerably lower than the current VOR approach off the Table Rock VOR allows.
Some of the reimbursable agency costs to develop an approach are actually inexpensive, even by today’s standards.
• Procedure development–$5,000 to $11,000
• Initial flight check–$2,800 to $4,300
• Recurrent flight checks–$1,800 to $2,850
• Quality control–$500 to $800
The FAA spokesman said, “There are many variables involved in the cost to produce a new instrument procedure, such as the up-front work by the regional flight procedures office in coordination with the FAA’s airports, air traffic and flight standards offices to determine the feasibility of developing a procedure; actual development of the procedure by the national flight procedures office; initial flight inspection; announcement of the procedure in the National Flight Data Digest; and publication/distribution of the procedure both in paper charts and electronic media by the National Aeronautical Charting Office. It would be very difficult to quantify the full costs associated with all of these steps and the various FAA offices involved in the process.” Both Withers and Madison also agree that the most exhaustive item during the approach certification process is the environmental-impact study.
Some of the environmental questions that regularly affect the certification process include whether parks, recreation areas, churches or historic areas might be overflown. Are there nearby wildlife preserves that are a concern? Are there pre-defined noise-sensitive areas near the airport? Are local community leaders aware of the approach request? How many noise complaints have been filed against the airport and by whom? What is an estimate of the increase in possible traffic due to the new procedure? Accardi said, “Another roadblock to certification is that airports often do not have current survey data when they begin the application process. That data is a must to proceed.”
Approach development is broken down into a number of blocks on an FAA flow chart that are further divided into additional subcategories. Once the request is received, the FAA determines whether the approach is for a public-use airport or whether a reimbursable agreement will be needed, as was the case at Aspen. The request is next forwarded to the regional airspace procedures team (RAPT) for an initial feasibility assessment and further coordination with the regional airports division that includes a review of all necessary survey data. From there, the FAA decides if the proposed new approach will fit into the agency’s NAS development plan budget and forwards it to the national flight procedures office. Once all coordination with the controlling ATC facility is received, the entire package moves to AVN-100 at Oklahoma City, where the actual design work is handled and checked for any unique safety considerations.
There is still much more work to be done from this point. Although some FAA sources would not hazard a guess as to how long it might take to certify a GPS approach, Accardi said an average start-to-finish time is about nine months, with some completed in less time and some a bit more. “The variable issue is the number of departments that are involved during the process. If it is simply an overlay approach, much less time is needed. We most likely will not even need any new environmental data.”
Jeppesen Can Assist
Bob Withers, Jeppesen’s manager of business development for government and military services, said his company designs instrument approach procedures, as well as special instrument procedures for private companies (it designed the new Aspen procedure). Jeppesen can design the entire procedure, fill out all the forms and deal with airspace issues. The only item the company does not handle directly is the surveys required to gather obstruction clearance data.
Withers said the cost of using a company such as Jeppesen for much of the legwork is equivalent to what it would cost to use the FAA. He added, “Most of our customers are usually as price conscious on the certification process when they are looking for flexibility for a $40 million aircraft.” Some publicly owned airports may be eligible for grant funding to cover procedure costs through AIP funds.
“One of the major problems for users who try to speed the development process on their own is that certification guidelines are found in a half-dozen different publications,” Withers explained. “There are people who would like to move approach certification into more of a cookie-cutter approach, but that is not going to happen. There are too many variations.
“Getting an approach certified depends on how you present the package of applications and other required documents to the FAA,” Withers said. “You can do it the easy way or the hard way. And the requirements from the FAA and ICAO are changing all the time.” He said more operational concerns for certifying an Rnav approach include designing an approach that delivers the minimum noise impact driven by airspace or obstacles. “We look at whether the approach will focus on ground- or space-based equipment, the accuracy of the equipment in the aircraft, such as the accuracy of the autopilot, and even the capabilities of the pilots.”
Once the approach package reaches the FAA’s Oklahoma City office it is checked to be certain that:
• Controlling obstacles in each flight segment are established.
• Protected areas around the controlling obstacles are identified.
• All other obstacles are identified.
• Maps and charts are reviewed.
• Supporting navigational aids are plotted.
• TERPs surfaces are identified and drafted (final approach; circling approach; missed approach; standard instrument departures; procedure turns; initial, feeder and intermediate areas; and holding airspace).
Approach minimums such as MDA, DH and necessary visibilities are also assigned. Next, all pertinent findings are recorded and the draft instrument procedure is reviewed to ensure that the procedure will meet the user’s needs. The draft IFP is next reviewed to see if it meets air-traffic flow directives. If not, it is sent back up the pipe for redesign, where any necessary waivers can be added.
If the procedure successfully jumps through all of these hoops, it is prepared for flight inspection, with the main criteria being whether the procedure can actually be flown as designed. After a successful flight check, the package moves to AVN quality control for a final check. If it passes muster and the approach is to be certified for a public-use airport, the entire package next makes its way to the national flight data center and NOS to be printed. If it is to be a private approach, the file is sent to the local FSDO for distribution.
Withers said, “The FAA is moving ahead as fast as it can on new approaches, mostly GPS-Rnav versions. We have much more outside-the-box thinking, though, to get us to the next generation. For that we must educate and train people to have confidence in the system, which involves some new long-term strategies. Most new aircraft come with equipment capable of extremely accurate Rnav approaches while others are still flying with only basic Rnav technology. Right now I think we’re stuck a bit between two worlds.”