s which in turn are limited by radar on the ground. The radar establishes radio-controlled air space in which the planes fly.
Every time the aircraft enters a radio controlled air space, the pilots need to change radio frequencies, and this could happen more than 25 times during a coast-to-coast flight. Moreover, during the flight, the plane is required to make adjustments to its speed and direction.
External circumstances such as bad weather may force a plane to divert from the flight path. According to FAA bad weather accounts for 70 percent of all traffic delays, often causing a ripple effect throughout airports across the country.
As it approaches its final destination, the airplane will make multiple preparations for landing by continually decreasing speed, descending, and leveling off—a process known as the “step-down approach.” This procedure repeats again and again until the pilot is given permission to touch down.
The NextGen Difference
The aim of NextGen is to replace the current ground-based ATC system with one that is satellite based. This transformation is not only more efficient, it will also be essential for the safety of passengers.
Before takeoff and after landing, the airplane maneuvers on runways and taxiways guided by air traffic controllers. The FAA has a variety of systems that allow controllers to see traffic moving at the airport.
Airports now use the Airport Surface Detection Equipment, Model X, or ASDE-X, which receives its information from different sources such as radar and other transmissions. ATC monitors this information in the airport tower, guiding the decisions of the controller. However, in bad weather the radar may show false objects on the screen, interfering with ATC decisions and procedures.
NextGen, on the other hand, employs the Global Positioning System (GPS) to find the precise location of aircrafts and other ground vehicles. This information gets transmitted not only to the control tower, but also to a monitor in the cockpit allowing for a faster and more accurate exchange of routing data.
With much of the coordinate information available directly to pilots, less radio time with ATC is required—decreasing the possibility of communication errors. When pilots and ATC can see this information simultaneously, automation is used in setting the order of departures, thus reducing delays even in bad weather.
Utilizing the ground capabilities of the Airport Surface Detection Equipment (ASDE-X)—a runway safety program used to prevent conflicts on the ground—NextGen takes it a step further incorporating a software tool called Surface Management. This extends the surveillance capabilities of ASDE-X beyond runways and taxiways to ramp areas, thus improving the position awareness between the airport control tower, the airline ramp management crews, and the airline operations centers.
Under the current system when a plane takes off, radar sends signals that bounce off the fuselage to calculate the craft’s position. However, since radar information can be off by as much as two miles, the system accounts for the discrepancy by separating planes at least three miles or more apart. With NextGen pilots will be able to know their position down to a few hundred feet.
Through precise navigational procedures, planes will use multiple departure paths. Add to this the aid of the Automatic Dependent Surveillance Broadcast (ADS-B)—another aspect of NextGen that also relies on GPS signals—and a craft will be quickly guided to its cruising altitude.
This system will see a plane swiftly navigating out of the busy airspace over the airport ascending steadily, thereby using less fuel, saving time, and increasing airport capacity.
The idea behind the ADS-B is to give pilots information that previously only controllers on the ground were able to see: the aircraft’s location, the location of other aircraft, as well as graphical and textual weather information on a moving map. This valuable information allows pilots to get decisions quickly and safely.
In addition, ADS-B will allow planes to fly closer together wi