Delta to perform continuous descent approaches in San Diego

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Delta Air Lines will begin using a continuous descent approach (CDA) at San Diego International airport in January, upping the number of US facilities where the fuel and emissions savings technique is used.

The SkyTeam alliance member's aircraft will be able to glide into the airport using minimal power, resulting in less fuel consumption and reduced emissions.

While San Diego's CDA procedure--dubbed LYNDI--is designed for multiple fleet types, the carrier has not decided which of its 13 average daily operations will use the CDA, Delta technical pilot Grady Boyce tells ATI.

CDA is not new for the US major, which first began testing the approach for night operations at Hartsfield-Jackson Atlanta International airport in April and May 2007. Between 10 and 13 arrivals per night from the West Coast operated with the CDA in a single-string arrival pattern, synchronized by air traffic controllers, Delta says.

The six-week trial involving Boeing 737-800s, 757s and 767s saved as much as 1,100lb (498.95kg) of fuel per approach, as compared with the descent methods normally used.

Delta began a second, 90-day night trial in Atlanta this August, recruiting FedEx, AirTran Airways and Atlantic Southeast Airlines (ASA) to diversify participating aircraft. ASA was also involved with design, but not actual flying since the Delta Connection operator did not have aircraft arriving during the necessary window, Boyce says.

Both AirTran's 717-200s and 737-700s flew CDA because the trial included all aircraft arriving between 4 a.m. and 7 a.m., an AirTran spokeswoman says.

The 737-700s were the smallest aircraft in the test profile, demonstrating fuel savings of 700lb (317.5kg), says Boyce of Delta.

CDA also trimmed flight time by roughly 2.5 minutes per flight, he says, noting this could have positive implications for fuel consumption considering Delta has 500 mainline operations daily in Atlanta, along with 400 regional operations at the airport.

The trial was to end on 18 November, but testing will be extended so carriers can try the procedure for daytime operations, Boyce says.

Both AirTran and Delta plan to resume the trials in January.

In addition to the Atlanta trial, Delta began using CDAs in Los Angeles this year. It is too early to quantify fuel and emissions savings, Boyce says, but he expects Los Angeles results will be mirrored in San Diego.

CDA is one form of a broader set of tailored arrivals that allow aircraft to use existing flight management computer technology-area navigation (RNAV)/GPS)- to cut fuel burn, noise and emissions while improving traffic predictability for air traffic service providers by arriving at a certain location at an assigned time.

San Diego's LYNDI glide can start up to 60 miles (96.6km) from touchdown, an FAA spokesman from the Western-Pacific region says.

The LYNDI approach was published in pilot manuals on 20 November and has a targeted start date in mid January, he adds, noting the arrival will be available to all aircraft with proper equipment.

In addition to San Diego, a CDA for Atlanta and South Carolina's Charleston International airport will be published for pilots by the end of next year, the FAA spokesman says.

The goal is to implement CDA at as many airports as possible, as soon as possible, he says.

Delta is also considering implementing CDA at outstations, Boyce says.

While the carrier would like to focus on hubs first, using the approach is logistically more difficult at larger airports, he says.

Meanwhile, FAA is working to quantify projected fuel savings and emissions improvements for San Diego. The administration has already seen positive results elsewhere, the spokesman says.

UPS began using CDA at Kentucky's Louisville International airport in January. So far, the company has seen a 34% reduction in nitrogen oxide (NOx) emissions below 3,000ft (914.4m) and a 30% reduction in aircraft noise within 15 miles (24.14km), the FAA spokesman says. CDA flying has also trimmed UPS fuel consumption between 250lb (113.4kg) and 465lb (210.9kg) per flight at the airport, he adds.