Ramping up radio communications
Dispatch radio plays an important role in coordinating Delta Air Lines’ communications on `the ramp,’ where intensive, recurring procedures include debarking, embarking, cleaning and refueling.
Despite the convergence of cell phones, laptops, PDAs and the Internet, two-way radio dispatch is still the workhorse for ground-to-ground communications for major airlines. Unlike a wrench, which is occasionally used and then thrown back into the toolbox, radios are vital instruments in “24/7” use.
Radio has been with the airline industry almost from its inception, and its importance has increased, rather than diminished, as the airlines have grown. Perhaps the biggest boost to radio usage resulted from the deregulation of the airlines in 1988. Previously, the FAA had regulated set numbers of flights from one city to the next. With deregulation, however, airlines introduced a practice (pioneered by Federal Express) called hub and spoke, in which an airline would have one city as a hub, or center of operations, directing its flights out through the spokes to various destinations.
Fierce competition resulted in specific major airlines dominating specific major cities. As a result, Delta became the dominant airline in Atlanta, United centralized its operations in Chicago, and American set up shop in Dallas.
Contemporary ideas about ramp control then came into being. Between landings and takeoffs, several intense procedures must take place on the ramp. All of the passengers and baggage have to debark from one flight while passengers and baggage embark on the next, in addition to the cleaning and refueling each plane undergoes between flights. These complicated procedures have increased exponentially as more and more aircraft have been fed into the hub cities. Dispatch radio has come to play an increasingly important role in coordinating these tasks.
To gain some perspective on this topic, MRT interviewed the manufacturer of a system designed to coordinate ramp communications, a manager at Delta Air Lines and a Delta tower technician who works with these communications.
Equipment to meet a need
Ronald A. Duncan, vice president, sales/marketing, Avtec, Gilbert, SC, provided an overview of why dispatch radio is such a vital part of ramp activities and what his company’s integrated radio console system contributes.
Distinct differences exist between the air traffic control and ramp control towers, Duncan said. The former activity is run by the FAAand entails directing aircraft into and out of the air space, as well as on and off the active airstrips. Once the aircraft moves off of the landing area and taxis to the gate, the responsibility and voice traffic are passed to the ramp control tower. This tower is above the roof line of the airport concourse to provide a clear view of what goes on below. These ground controllers are in active communications with all of the crews responsible for finishing up one flight and preparing for the next.
Those crews encompass everything that has to do with the operation of the aircraft, including passengers, baggage, fueling, maintenance and repair, catering and cleaning. At least two people are in the tower for each operations function, and they are in constant contact with the crews via radio.
“During certain periods of the day there can be a sudden shift from the fairly leisurely to the very intense,” Duncan said. Certain periods are called “push,” when numerous tasks involving the aircraft must be performed within an hour, from garbage removal to restocking catering. The goal is to get the passengers off the plane and to get it maintained, cleaned, refueled and recatered within 20 minutes.
To give some idea of the magnitude of the task, in 1999, Delta, throughout its entire system, handled 106 million passengers, and conducted 5,4001 flights with 584 aircraft in 364 cities in 61 countries. At the Delta terminal at Atlanta’s Hartsfield International Airport, 1,800 Motorola GTX mobile and portable radios aid in coordinating the process.
Yet with all of these simultaneous ramp communications, one might imagine that ramp control would be a Tower of Babel. That’s where the Avtec DSPatch integrated console system becomes crucial, Duncan said. Like the airlines’ overall operations, it serves as the hub, feeding many communications spokes.
With a conventional system, keeping all of the circuits of different frequencies connected would be a difficult task. However, the console system in place at Hartsfield can connect the “spokes” regardless of what frequency they may be using.
“If they have an aircraft that is operating on the VHF AM band, and they want to be able to communicate with a maintenance person on the ramp who is operating on an 800MHz portable, since both of those go through the same switch the operator can simply patch and allow the crew member to speak to the person on the ramp,” Michael G. White, manager of transportation sales for Avtec, said.
All of the radio communications, (conventional UHF or VHF, 800MHz or 900MHz) whether for ground-to-ground or air-to-ground voice traffic, come through the same switch along with telephone messages. One integrated dispatch console allows operators to access or manipulate any of these channels.
Avtec pioneered this technology when the company got started in 1979.
“One of the railroads came to us with a similar communications problem, and since then we’ve sold the unit to virtually every other railroad,” Duncan said.
Other markets the technology has been applied to include public safety, utilities, the military and water transit.
White stressed the importance of a smooth-running dispatch system in ramp control.
“We consider this mission-critical equipment. There’s a high degree of redundancy, for there is no allowance for failure. It has to be up and running every day, 24 hours a day,” White said.
The system’s redundancy exists on two levels. Between the power supply and the shelf controllers, all angles are covered.
White said the power system runs on 48Vdc. In the event of a failure in one of the power supplies, the system, which is continually running diagnostics, will sound an alarm to alert the staff, but the system itself will continue to run.
The 32-port termination shelf houses the interface cards and the console interface cards, and the shelf consists of two shelf controllers. As the “clearinghouse” for all digital audio and data, the shelf is counted on to remain in service regardless of the situation. With the two-shelf-controller architecture, the system is guaranteed to continue running in the event of a failure within one of the interface cards.
“Our markets have historically demanded what we refer to as a `one-for-one architecture,’ meaning for every radio base station that we interface to, there’s a single card that brings that into the switch,” White said. “You can lose a line, you can lose a position, but you can’t lose an entire shelf or an entire switch.”
While Duncan and White have developed a broad-based perspective from working with several airlines, Carl Rowe, an assistant manager at Delta Air Lines in Atlanta, has a more specialized knowledge of the ramp tower.
Rowe said that the system’s round-the-clock use makes it invaluable whether the number of crew members using it is four during the night shift or 150 during peak times of day.
Rowe said system users face a learning curve because a multitude of frequencies must be monitored at any given time.
“In a previous version of the unit, you were not able to adjust the volumes,” Rowe said. “This tended to make things difficult.”
With almost 40 frequencies to monitor, volume adjustment was an important factor. What Avtec provides, Rowe said, is the capability to adjust the volume. Now, a controller can adjust the volume of different channels through the headset by priority: the most important, the loudest; the less important, a bit quieter; and the least important, quietest.
“Three volume levels are about as many as one person can handle,” Rowe said.
Any one person will monitor three related functions, such as talking to the pilots, passenger service agents and baggage handlers. Rowe added that an intercom function allows a supervisor in the tower to override all of the other communications for an emergency or priority message that everybody should hear.
Working ramp control
Steve Gerrin, Delta technical analyst, works at ground zero in the ramp control tower. Gerrin said that controllers in the tower, which might have as many as 50 people in it at any time, used to monitor the radio communications over speakers, which created confusing ambient background noise. The transition to headsets, so that one person only monitored three radio frequencies, was a big step toward greater efficiency and less strain on the nerves.
Gerrin reported that most of the radios in his area are part of a Motorola trunking system, which can handle as many as ten frequencies and has much more versatility than conventional operation. Gerrin also said that although the Avtec unit allows for phone integration as well, the Delta Atlanta ramp tower doesn’t use it.
“Straight radio communications do the job,” he said. “Cellphones are more for one-on-one conversations, which a manager might use to talk to the head office. But for our purposes, radios are much more durable than cell phones.
“For our airline ramp operations, radio is indispensable.”
The final approach
It’s easy to forget about all of the “little” things that have to be done to ensure that plane arrivals and departures “take off” without a hitch. But ramp controllers and the activities they oversee are just as important as the pilots and the air traffic controllers. They make sure your plane gets refueled and restocked. They watch for problems with the planes and fix what appears to be broken. And, yes, they coordinate baggage transfer so your luggage makes it onto your connecting flight.
Behind every good ramp controller is a good radio. Without a trunked radio system, the employees on the ground at Atlanta’s Hartsfield International would be reduced to the unimaginable task of shouting incoherent orders to each other amid the deafening roar of aircraft jets. With the help of Avtec’s dispatch console system and a Motorola trunked radio system, however, the people you trust to safely get you off the ground and where you want to go can stay grounded.