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Baby steps to NextGen: figuring out the what ATC's NextGen service will be is a hot debate, but pieces of the puzzle are already being installed.

Center calls, "Turn 20 degrees left, vectors behind traffic at 10 o'clock, 15 miles." You acknowledge, turn and see the traffic closing on your MFD display. You realize you'll definitely pass less than the required five miles from the traffic, and it's at your altitude. And you're in the soup.

When the controller clears you to resume own navigation, his voice sounds normal--no hard breathing or high-pitched voice. How is it possible he didn't lose separation?

The Tight Pass

The controller was using three-mile separation instead of five. This is the world of En Route Automation Modernization (ERAM), the FAA's former display system replacement DSR program with new blood. In areas designated by the FAA, controllers will be authorized to use three-mile separation between aircraft. Controllers have the ability to depict these areas on their display and the data block changes when it enters an area of reduced separation to alert the controller that reduced separation is approved.

ERAM will support the NexGen systems such as ADS-B and ICAO flight data. An item that will be notable to pilots is labeled End-To-End Route Conversion. It works this way: You file your flight plan from Amarillo, Texas, (KAMA) to Atlanta, Ga., (KATL) in your new Pilatus. The route you choose is direct Childress VOR (CDS), direct Vulcan VOR (VUZ), direct LaGrange VOR (LGC) and the La Grange One Arrival. Direct Childress will keep you clear of the Hollis MOA (and the similar ATCAA above it) during your climb to the flight levels. When you contact Clearance Delivery for clearance, you hear, "Cleared to the Atlanta airport as filed except change route after Childress via direct Meridian, LaGrange six arrival, Meridian transition, maintain ..."

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Plugging the revised route into the Honeywell Apex, you see ATC changed your route out of Childress about 15 degrees further south and is actually saving you from the 45-degree turn you normally get 70 miles west of Vulcan. Without the ERAM Route Conversion, Memphis Center would have issued the route to comply with the Atlanta Center Letter of Agreement. With ERAM, you win a better routing and you get the change before takeoff. End-To-End Route Conversion does not rule out the possibility of an airborne reroute, but it reduces it substantially.

The Backstory

FAA's ERAM program began over 10 years ago with the introduction of the User Request Evaluation Tool (URET). URET was enthusiastically accepted by controllers because of a spin-off not anticipated by the developers: URET virtually eliminated the use of the pesky and unwieldy flight progress strips, those ridiculous strips of paper containing flight data that had been used since the invention of ATC.

Hence, controllers love URET because it eliminates the time previously consumed by posting, updating, scanning for conflicts, re-sequencing for time revisions, marking the strip for radar contact, radar contact lost, and a final mark when the aircraft was changed to another frequency and then the physical removal of the strip from the board.

Today, most Centers don't use any strips in the high and ultra-high sectors at FL240 and above except for special flights such as Air Force One. Low-altitude sectors, normally FL230 and below, use strips for arrivals and departures at non-approach-control airports or special flights such as military IR routes.

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The URET computer alerts the controller if two or more aircraft are projected to lose separation or if an aircraft's route will enter an active special-use airspace. In this aspect, URET is immensely superior to even a top-notch controller using only strips to formulate a "picture" of traffic in the controller's mind.

ERAM will enhance URET capabilities even more. The current system uses a mainframe host computer for the DSR radar display or "R" position and a separate computer and software for URET, which is located on the Radar Associate or "D" position. This requires controllers to be proficient in two different systems depending if they are working on the D or R position. ERAM merges these two into a new computer system and eliminates the quirky, two-system programming.

Helping in the ERAM picture is the En Route Information Display System (ERIDS), which appeared in 2006. Analogous to modern glass cockpits, ERIDS makes the controller's life easier and more efficient by eliminating paper copies of IAPs, letters of agreement, NOTAMS, etc., that always seemed to be missing when needed. (See "Center Needs Tools Too," May 2006 IFR.)

ERAM has two, redundant channels and a computer on each controller position that will, theoretically, eliminate maintenance downtime as well as unscheduled outages. If so, ATC Zero may be a thing of the past in respect to automation. (See "ATC Zero," December 2007 IFR.) However, ERAM does not change the current communications system. Data blocks are updated continuously with multi-sensor tracking instead of the 10-second update currently in use. That provides the controller with a real-time, accurate display of an aircraft's position.

The Neighbor's Grass

ERAM will introduce another safety development known as the Surveillance Area of Interest. It can be viewed as a system that enables a controller to see a potential problem developing in another Center's airspace and perhaps lend a helping hand. Normally, Centers don't have data on aircraft that aren't flight-planned to enter their airspace. Unplanned deviations, as when a line of thunderstorms rolls through, can trash the plan and leave Centers scrambling to coordinate traffic.

The Area of Interest consists of all the airspace that belongs to adjacent Centers. Within this airspace, controllers will receive URET alerts and have the capability to display data blocks. This means each Center will have flight data on aircraft even when the aircraft's planned route will not enter their airspace. Coordination between Center controllers will be substantially easier.

Extending even further outward beyond the Surveillance Area of Interest is an area designated the Flight Planning Area of Interest. As its name implies, only flight plans will be available within this area. This is a major change in how ATC does business and could eventually evolve into a realistic method for one Center to absorb another Center's airspace in an emergency.

The last phase of ERAM may be completed in some Centers in late 2008. Memphis Center will start ERAM controller training in early 2009. They are scheduled for their Operational Readiness Demonstration in June 2009. The only change you as a pilot should see is fewer airborne route changes and, perhaps, a reassuring calm in the controller's voice that everything is going swimmingly.

Charles D. Richardson is a retired Center controller still active in ATC training.
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Title Annotation:SYSTEM NOTES; air traffic control
Author:Richardson, Charles D.
Publication:IFR
Geographic Code:1USA
Date:Oct 1, 2008
Words:1088
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