Explained: The National Airspace System, JFK to LAX

DALLAS — The general public does not see a facet of air travel. Beyond the customer-facing aspects of safety and security lies the exchange between pilots and Air Traffic Control (ATC), a part of the National Airspace System (NAS). It is an intricate and coordinated system designed to provide for the safe separation of aircraft as they traverse the sky.

The journey of an airplane through the ATC system is usually a seamless process that is mirrored all over the world. Experienced air traffic controllers and pilots follow standard phraseology to allow for an efficient and effective manner of communicating with each other.

This article will follow an airliner through the NAS on one of the busiest US routes: from John F. Kennedy International Airport (JFK) to Los Angeles International Airport (LAX).

The Flight Plan

Before loading up and heading west, a route must be selected and submitted to ATC by an Airline Dispatcher. Several options exist for routes between the two cities. Usually, it is selected based on optimal fuel burn, the airplane's weight, and other weather-related factors. Today, we will fly the route below, frequently used for JFK to LAX flights.

KJFK DEEZZ5 CANDR J60 DJB RIEKE KC72Q UNBAR J584 OBK J100 DBQ CAPPR JORDY KP72E KD66Y KD63W ZAKRY CHESZ Q88 HAKMN ANJLL4 KLAX

The structure of the flight plan above is:

• The International Civil Aviation Organization's (ICAO) code for the origin airport
• The Standard Instrument Departure (SID) Procedure: DEEZZ5 CANDR transition
• Enroute waypoints, airways, intersections, and ground-based navigational aids
• The ANJLL4 Standard Terminal Arrival Route (STAR) procedure into LAX
• The ICAO code of the destination airport

SIDs and STARs allow for an orderly flow of departing and arriving aircraft. In some instances, alternative instructions from ATC may partly or wholly supplant the SID or STAR procedure; however, it is standard practice to include them in the flight plan.

For our flight today, we will imagine that winds at Kennedy are out of the northeast and plan for a takeoff on runway 4L.

Pushback, Taxi

The gate areas at JFK are often busy with planes coming and going from the tarmac. The crew contacts ramp control for approval for pushback to mitigate the possibility of an incident. Ramp control is not considered a part of the ATC system and is controlled by the airline (in this instance). The FAA regards the gate and ramp area as a "non-movement" portion of the airfield.

Once off the gate and both engines are spooling, the pilot monitoring (PM) on the radio calls JFK Ground Control for clearance to taxi. When initiating contact with ATC, the pilot will first state the name of the facility they are calling, then identify who they are, where they are, and what they want to do.

• PM: "JFK Ground, Flight 123 at the terminal, ready to taxi to 4L, information bravo."
• JFK: "Flight 123, JFK Ground. Runway 4L, taxi via Alpha, Kilo, cross runway 31L."

Information Bravo references the latest automated weather report provided by the airport, and the ground controller provided instructions that included a set of taxiways and clearance to cross an adjacent runway to get to the active runway.

Takeoff, Departure, Transition to Enroute

After crossing runway 31L in the taxi, Flight 123 was told to monitor the JFK tower frequency. Now, at the end of the runway and ready for takeoff, JFK Tower will clear it for departure."Flight 123, winds 050 at 11, runway 4L, cleared for takeoff." The PM repeats takeoff clearance, and the roll begins.

Once airborne, the plane turns right to a 99º heading, and the tower controller instructs the crew to contact New York Departure Control. The departure controller provides vectors (headings) to get it to the CANDR intersection, the transition waypoint on the DEEZZ5 departure. You can think of this as the onramp to the jet airway (J60) that ultimately leads the flight to Los Angeles.

While in the departure phase, likely approaching CANDR, the departure controller instructs the pilots to contact the New York Air Route Traffic Control Center (ARTCC). The airplane will reach cruising altitude in another few minutes. And so begins a set of handoffs between ARTCC facilities that continues to southern California.

Enroute

There are 22 ARTCCs in the United States managing high-altitude air traffic. Following New York, the Cleveland ARTCC will monitor this flight. After that, controllers from Chicago, Minneapolis, Denver, Salt Lake City, and Los Angeles Centers will all speak to these pilots. They provide traffic and weather advisories, turbulence reported by previous transiting aircraft, and other essential information that may affect the route.

ARTCCs are further broken down laterally into sectors and vertically by low and high altitudes. They may have different frequencies depending on staffing levels, workload, or some other determinant. So, any cross-country flight may communicate with at least two controllers within the same ARTCC facility because they are traversing different sectors within that facility.

During these hours flying over the US, the pilots receive updates from the dispatcher and cross-check planned versus actual flight elements like waypoint crossing times, weather along the route, and fuel burn. The relative calmness of the en route phase of flight allows them to eat, chat, or have alternating break periods. They may also brief the arrival and expected approach as they near the descent.

Descent, Approach

About 35 nm south of Las Vegas is the HAKMN waypoint, the first fix on the ANJLL4 STAR that will tie the arrival leg to the approach to LAX. The remaining transfers between ATC facilities are in reverse order of departure from New York. Fortunately, the weather ahead is clear and does not call for any deviations from the published route.

Flight 123 continues to follow the STAR and soon passes SHTNR and SMASH, where it begins its initial descent. Meal service has wrapped up, and soon, the fasten seat belt signs will illuminate for the remainder of the flight. At SALYY and on the way to the GLESN and ANJLL waypoints (the theme underlying this route is very tied to Hollywood), a more direct turn toward LAX.

Once the plane is lower, slower, and closer to its final destination, the handoff to Southern California (SoCal) Approach Control occurs. Progression on the route continues, and soon we are past the CRCUS intersection, the final waypoint on the ANJLL4, and the initial approach fix for the runway 25L ILS (Instrument Landing System) approach to LAX. Tower Control is next.

Landing, Taxi to Gate

Southeast of downtown Los Angeles and lined up for a landing on the southernmost runway, the PM establishes first contact with the tower controller.

• PH: "LA Tower, Flight 123, is one mile outside GIGII, ILS 25L."
• LAX: "Flight 123, LA Tower. Winds 250 at 7, runway 25L, cleared to land."

There is no further expected communication between ATC and the PM before landing. The primary focus is a safe and as smooth as possible landing. Soon after, the asphalt meets the landing gear, spoilers and reverse thrusters are deployed, and the airplane slows to taxi speed, exiting the runway at some point short of the departure end.

The last communication from the tower follows: "Flight 123, turn right, cross runway 25R, and then contact ground .75" (as in 121.75 - usually abbreviated since ground frequencies commonly begin with 121). The PM complies, contacting Ground Control for taxi instructions. The ground controller gives clearance to taxi to the ramp. The gate area may be free and available, or ramp control may delay parking at the gate if the arrival is significantly early and space is not yet accessible. Once at the stand and safely parked, the engines are shut off, and our flight and its place in the ATC system terminate.

Conclusion

Air Traffic Control is probably most associated with the airport control tower; however, that is just one small part of a complex network. Controllers are a guiding hand to the thousands of airplanes flying in the NAS at any given time. Their work and the service they provide are an integral part of air travel that should not go unnoticed.

Featured image: Control tower at LAX.

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