CDRs coming soon for business aviation

 - September 13, 2006, 11:49 AM

Coded departure routes (CDRs), which have been tested in business aviation during the past three years, are on track for deployment throughout the U.S. by October or November.

A CDR is a preplanned route between departure and destination points used to provide more route flexibility during severe weather conditions or high traffic volumes. Airlines began using them about eight years ago, according to Jo Damato, NBAA senior manager for air traffic operations.

Unlike preferred routes, CDRs are not just one way of getting from Point A to B. Rather, they are multiple alternate routes that ATC can assign depending on how weather or traffic affect the entire route or just portions of the route. The benefit of CDRs is that they greatly abbreviate the clearance-delivery process. A typical CDR route code is “TEBFLL60,” which replaces the lengthy route string  “KTEB ELIOT J60 DJB J85 TAY J75 TEPEE FORTL4 KFLL.”

For the airline implementation of CDRs, each airline had to sign a letter of agreement with each ATC tower where the CDR would be used. For business aircraft operators, crafting letters for each city pair would be impossibly unwieldy. Three years ago, the FAA began testing a system under which pilots add the words “CDR capable” in the remarks box on flight plans, which would serve as a letter of agreement. “That indicates to the tower that they’re familiar with the process,” Damato said.

The FAA test involves departures from three airports–Teterboro and Morristown in New Jersey and White Plains in New York. Because CDRs are alternative routings and take many shapes between the same departure and destination, the FAA created a database to manage them. To use CDRs, pilots must have access to the database, either by going to or through flight-planning providers.

Managing Traffic Flow

If an operator is planning a flight, for example, the provider will deliver a list of CDRs for that route, including each CDR route code and route string. There could be as many as nine CDRs for a route, and the operator must be willing and able to fly each CDR because the actual CDR won’t be revealed until the operator gets the clearance. The ability to fly all CDRs for a route primarily means having enough fuel for a route that could add dozens of miles to a trip.

There is no way for a pilot to know if a CDR will be issued for a particular flight before he calls for the clearance. Damato said that some pilots have concluded that the system doesn’t work because they have never received a CDR, but this is because weather or traffic conditions didn’t create the need, even though pilots filed “CDR capable.” CDRs are in effect only when weather conditions or traffic volume dictate, she explained.

Not all city pairs have CDRs, although the database will grow if the FAA implements the system nationwide. Operators can request that new city-pair CDRs be created, but they shouldn’t expect the FAA to go to the trouble for infrequently flown trips, Damato said. The FAA has to keep the CDR database updated on a 56-day cycle, and “it’s a work-intensive responsibility,” she explained.

The move to expand CDRs nationwide cleared the FAA legal experts in May, and the next step is for the agency’s systems operations, terminal and en route specialists to sign off on national CDRs. There will be a 60-day public comment period followed by any necessary changes, and then CDRs will become a new operational procedure for business aviation.

“NBAA will get the word out,” said Damato, and there could also be a description in the Aeronautical Information Manual and ATC Handbook. “We’re hoping we’ll be able to say this is a national procedure available to business aviation by October or November, for the snowbird season.”