When you fly in the United States, you take it for granted that you will fly safely from place to place. What makes that possible?

Most people are familiar with the airport. They arrive and check in their baggage and themselves. They board the airplane and then sit back, relax and enjoy the ride.

Passengers arrive safely at their destinations, on time and ready to begin the next leg of their journey. They claim their baggage and leave the airport.

So what makes this happen? The NAS helps to make this happen. So what exactly is the NAS.

The NAS is a collection of systems, used by people, following certain procedures.

Passengers tend to experience only a small part of the total system, the airport. The airport is the most obvious part of the NAS. It visibly represents the hustle and bustle of the entire system. People and things moving from place to place.

In each piece of airspace, many pieces of equipment must operate in harmony.

Navigational aids provide location signals to pilots. Each domain, or type of airspace, has unique requirements for precision. The accuracy needed to land in poor weather conditions is demanding. During the en route portion of a flight, navigational accuracy, although important, can be less precise.

The current NAS is based on a number of fixed routes, or highways in the sky. These routes are directly related to the ground-based navigational aids available to the pilot.

The western portion of United States has benefited from the removal of restrictions, which were based on these routes. Airplanes can now request direct (point-to-point) routes between certain locations. East of the Mississippi, there are more airplanes flying at any given time due to the proximity of major hubs to one another (for example, Philadelphia to New York, Washington to New York, Washington to Boston, etc.). Better accuracy of positions to both the controllers and pilots is required to safely ensure the removal of restrictions and allow more direct flights.

In an age where the Global Positioning System (GPS) is available for our cars, we should be using it for aviation as well. The currently approved navigational aids of the NAS do not take full advantage of GPS. The NAS, while very good, can be improved and flights can be made even safer through the use of augmented GPS.

Without radios, controllers and pilots would not be able to verbally communicate. On many flights, passengers can listen to the pilots and controllers. As the aircraft moves from one domain to another or from one sector to another, a new controller becomes responsible to monitor and control the flight. A sector (volume of airspace) is like county lines on a map extended upward in the sky. Each controller has the responsibility for the activity within one sector.

The current radios are based on the 1960's technology. Controllers and pilots can communicate some information without voice communications (initial clearance information, Pre-departure Clearance). Over the Pacific Ocean, we have established some non-verbal real time communication links, called Oceanic Data Link. However, most oceanic communications are relayed through a third person rather than using satellite technology.

There is no radar coverage over the ocean. Pilots must report their positions verbally or have them automatically sent through a relay station. The automation system acts like a big calculator and displays the position of the aircraft to the controllers. Because of the delays imposed by relaying communications, it is hard to accommodate requests for route and altitude changes over the ocean.

Oceanic Services Safely Meet Future Demand for Flights to Europe, Asia and the Pacific Rim

For the controller, surveillance equipment, primarily radar, detects the position of the many moving aircraft. The update rate, or rotation rate of the radar antenna, varies by each domain of flight. The radar monitoring surface movement of aircraft and other vehicles spin much faster than those radars covering en route and terminal airspace. The surface radars provide more timely position data of specific aircraft.

Surveillance or position information is processed by computers and displayed to the controllers on large computer screens. New tools to help the controllers move more aircraft safely through the system have been developed. After years of research, these tools are now installed into some of the air traffic control facilities.

The controllers use automation tools (displays with computer processors and aviation software) to assist them with the tracking of aircraft. The aircraft submits a flight plan prior to take off. The automation systems monitor the progress of the flight with the radar information. The controller knows where the aircraft is located as well as where the aircraft is heading.

The current NAS is aging. Automation advances in recent years have been amazing. The enroute mainframe computers and the display system are being replaced now. All the terminal automation equipment is scheduled to be replaced. These older systems are not capable of accepting the new tools controllers need. Therefore these systems must be replaced.

Likewise, our telecommunication circuits have limited capacity and use old technology. These systems must be upgraded or replaced in order to meet demand for increased capacity.

Most NAS facilities were built in the 1950's. Some have been renovated. Many, though, need repair. Roofs leak. The power supply within the facility is unreliable. The buildings are too small. Access control is not compliant with federal law. Security is not adequate.

NAS Modernization has three key categories. The first category focuses on upgrading the infrastructure. The second category focuses on providing new safety features. The third category introduces new efficiency-oriented capabilities into the existing system. All the efforts associated with these three categories must be integrated. The evolution to a modernized NAS must be well orchestrated and balanced with the resources available.

New safety and efficiency capabilities require new tools and procedures, as well as training for controllers and pilots. But for the new tools to work efficiently, the infrastructure must be sound. This infrastructure includes buildings to securely and safely house the processors and displays for the controller. It also includes radar and radios. For the terminal area and many of the towers, STARS ( the Standard Terminal Automation Replacement System,) is the key to the future. STARS will replace the displays and processors. It will provide a solid foundation for new capabilities.

For STARS to work successfully at many of the facilities it will be necessary to upgrade power systems and communication systems within the facility. Some facilities must be modified to be brought up to current standards for safety and security. In a few cases, structural repairs must be made before STARS can become operational.

Like our nation's highways, the facilities in the NAS are aging. Many of the Towers, TRACONs and ARTCCs need to be upgraded to meet current standards. OSHA standards, earthquake standards, power standards, and others have changed in the past 30 years. It is time for many of these significant repairs and upgrades to be accomplished at facilities housing our air traffic controllers.

Many facilities in the NAS house radios or other equipment. These too may need new roofs, more reliable or "cleaner" power, or a host of other facility modifications. It is crucial that we keep our NAS systems protected. Lost radar or communications signals can slow the flow of aircraft to a busy city. This may cause delays throughout the entire region, or possibly the whole country.

The second category for modernization activities focuses on the upgrades for safety.

Weather has a big impact on the NAS. Fog in San Francisco, snow in Denver, thunderstorms in Kansas, wind in Chicago; all these reduce the safety and capacity of the NAS. Although we cannot control the weather, we are making great strides in being able to predict the weather. Controllers are receiving better information about winds and storms. The pilots are receiving better information before they take-off. All this makes flying safer.

Another cornerstone of the future for the FAA is improved navigational information available in the cockpit. The use of GPS will become more widely accepted. The Wide Area Augmentation System (or WAAS) will supplement GPS and provide pilots the accuracy they need for most flights.

This improved accuracy helps the pilots know their positions, which increases safety of flight. WAAS also enables improvements in efficiency, by providing access to more runways in poor weather, due to the precise navigation service it provides.

The Local Area Augmentation system (or LAAS) is being developed to provide even better accuracy than either GPS alone, or GPS with WAAS. LAAS will provide localized service for final approaches in poor weather conditions at major airports. Airports that require LAAS will be most of the top 100 airports in the United States and a few selected other locations that need the local signal due to other technical reasons.

This additional navigational accuracy that will be available in the cockpit will be used for other system enhancements. The Automatic Dependent Surveillance (ADS) system being evaluated by the FAA and airlines, takes advantage of this improved accuracy.

The ADS system will allow the aircraft to automatically transmit or "squitter" its location to various receivers. This "squitter" or broadcast mode is commonly referred to as ADS-B. The ADS-B signal can be received by other properly equipped aircraft. It also can be heard on the ground by receiver stations. The ground stations can then feed the automation system accurate aircraft position information. This more accurate information will be used to improve the efficiency of the system and is related to the third category of modernization activities.

New Procedures & Equipment Promote Fuel Efficient Flights

Other key efficiency improvements will be found in the deployment of new tools to assist the controller.

Over the ocean, most commercial aircraft already have equipment to send their GPS positions automatically to receiver stations. This is the key enhancement needed in all the oceanic airspace to allow more efficient use of airspace.

Improving text and graphical message exchange is the ultimate goal of the Controller Pilot Data Link Communications (CPDLC) Program. The first step is CPDLC Build 1. This step allows the FAA and pilots to understand how roles and responsibilities can change based on the increased exchange of information. This step will be conducted at Miami, and although the field test is still a few years off, preparations are under way by both the FAA and American Airlines.

In the en route domain, DSR, the Display System Replacement, along with the Host/Oceanic Computer System Replacement, HOCSR, and Eunomia projects, are the platforms and infrastructure for the future. These provide new displays to the controllers and upgrade the computers to accept future tools, and provide modern surveillance and flight data processing capabilities. For CPDLC to work effectively, it must be integrated with the en route controllers' workstation.

We have begun to implement tools requested by the users through a project called Free Flight Phase 1. The National Civil Aviation Review Commission warned of impending gridlock at many of our major airports. Airlines say they will run into difficulties scheduling their flights without undue delays as early as 2005. We must expand airspace capabilities to meet growing demand.

More than preventing gridlock, Free Flight Phase 1 provides the incremental steps the FAA needs to take to modernize the National Airspace System. There are five tools associated with Free Flight Phase 1.

The User Request and Evaluation Tool (URET) is designed to help en route controllers predict the future flight path and identify potential conflicts. This tool helps controllers to allow planes to deviate from filed routes to avoid poor weather or to take advantage of favorable winds.

Another tool to be used in the ARTCC is called Traffic Management Advisor (or TMA). This tool assists traffic management specialists with developing arrival sequence plans for selected airports. Currently this tool is effective at airports that receive airplanes from one ARTCC.

Both URET and TMA will provide key improvements and are being implemented on a limited scale. These tools will help the aircraft fly a more direct route from point to point. And, both of these tools operate on the new en route displays.

Improved Transition Between Airspace En Route and Terminal Airspace

Another key set of tool to ensuring that aircraft can arrive at their destination on time is Collaborative Decision-Making.

Collaborative Decision-Making, (known as CDM,) provides airline operation centers with real time access to information about the status of the NAS. This includes information about weather, equipment status, and known delays. With this information, the airlines, are able to better anticipate "trouble spots" and start to prepare contingency plans. Although this may not prevent a passenger from being delayed by poor weather at their destination, it does help airlines avoid stranding passengers and airplanes.

Improving operations around the airport is critical to most major airlines. Two tools are currently being tested to improve traffic flow around the airport. Both of these tools work with the Terminal Automation systems.

The first tool, pFAST (the passive final approach spacing tool) is used at the TRACON. It helps controllers sequence aircraft and assign runways based on user preferences and airport constraints.

Sharing of information is very important to the improvement of NAS operations. The second tool to improve operations near the airport increases the sharing of information between the FAA and the airlines and is called SMA (or Surface Movement Advisor). The purpose of this tool is to provide information about arriving and departing aircraft to the airlines. Information, such as identifying the runway and the sequence for landing, enables the airline to plan better. This is most critical at hub airports when airplane turn-around times at the gate are closely scheduled.

We are currently engaged in the difficult task of modernizing and expanding the aviation system. We are looking to the future. We can build on our current successes.

Our current successes are a powerful demonstration of what can happen when government, industry, and aviation system users reach consensus, follow a plan, and work together.

The NAS is critical to the American economy. We depend on the NAS to enable us to move from place to place. We depend on it to move our mail and packages. Our businesses depend on it to supply raw materials, provide orders and deliver final products. We must protect and improve this vital national resource.

This is an exciting time to be in aviation. Together, we can make a very big difference. Together, we can build the air traffic control system for the 21st century. Together, we can operate the world's best aviation system.