a 757 leaves Boston Logan for Los Angeles International, about 3,000 gal. of fuel is sucked up from an underground piping system and injected into its tanks. The system is pressurized and linked to hydrants established at gates. Hydrant carts with hoses and pressure controls connect to aircraft fuel tank intakes. For transcontinental flights, the process usually takes about 15 min.

"We have a hydrant at every gate," says Massachusetts Port Authority Aviation Director Edward Freni. "It's much quicker and more efficient than using fuel tankers. You just hook up to the wing and turn the pumps on. There's a meter to measure intake and an automatic shutoff valve. Pilots get a slip that shows how much fuel was administered."

At many airports, especially in the US, carriers belong to fuel consortiums that operate and maintain fueling infrastructure and manage logistical operations such as delivery and distribution. A lot of these consortiums were formed after numerous oil companies relinquished control of storing and dispensing fuel at airports about 30 years ago. Nowadays, fuel management and the processes related to fueling commercial aircraft tend to vary from airport to airport.

The fuel consortium at LAX operates and maintains on- and off-airport fuel storage facilities and distribution lines, but it's the responsibility of individual tenants to maintain the fueling systems at terminals. This may involve such activities as conducting pressure tests, replacing parts and ordering equipment.

The fuel consortium at Chicago O'Hare operates a bit differently. A single operator, selected by the City of Chicago under a lease agreement with the consortium, runs the fuel tank farm and the major distribution lines. Airlines agree to use that operator to maintain fueling systems at terminals and pay any costs associated with operation and upkeep. "The City says that all parties must use a single operator to maintain all parts of the airport fuel system," explains Lufthansa North American Fuel Purchasing Manager James Zak. "They control who does the work and who doesn't do the work and therefore it's kept within one house."

Conversely, at Boston Logan a consortium handles all infrastructure, logistics and maintenance related to fueling. Comprising 27 airline members, the fuel consortium hires a company to manage fuel tanks, distribution and hydrant systems. The arrangement eliminates the need to keep track of individual terminal tenants and multiple cost breakdowns because the consortium pays one lump sum. "Other airports may do things differently, but we've found this to be a very efficient, safe and consistent way to distribute fuel to aircraft," says Freni.

At most major airports in Europe, fuel facilities are still operated and maintained by oil companies. Shell, ExxonMobile, Air BP and others handle fueling activities and lease land from the airport. Hub carriers, because of the volume of fuel they purchase, may have a different relationship with these companies than smaller airlines. "You have to look at this on an airport-to-airport basis," Zak advises. "You need to know what the situation and structure is beforehand, or you learn it quickly when you start operating there. We just started operations in Seattle and Calgary this year, and at both airports [in those cities] they have fuel consortiums."

PROVISIONS & DISTRIBUTION

Airlines can deliver and distribute fuel in several ways. They can have it shipped by bulk in barrels or have it delivered directly into their aircraft. Fuel could be sent into a pipeline, delivered directly into fuel storage tanks at the airport or transported to an off-airport terminal facility before it is delivered onto the airport.

Boston Logan keeps about seven days worth of fuel on-airport and also relies on an off-airport barge facility with a storage capacity of about three weeks. "The on-airport stuff there is in pretty good shape," says Richard Marchi, a senior adviser at Airports Council International and a former director-aviation planning and development at Massport. "As they have a limited pipeline supply, fuel gets shipped in from nearby depots. They need to work out a higher-capacity pipeline feed system. That's just a matter of economics, because it's so much more expensive to bring in fuel with tankers than to pipe it in."

While each airline is responsible for purchasing and delivering its own fuel, when fuel arrives at the airport it usually is commingled in common storage facilities. Estimated fuel loads typically are based on aircraft type and utilization, route structure and projected fuel burn. The captain routinely specifies fuel quantities for flights. "It's not unlike going to the gas station with your automobile," explains Zak. "The captain says how much fuel he needs, they pump it in and that forms the basis of the invoice that is sent to the airline. Tickets are kept and either that's what they bill you or the amount of the fuel is deducted from your inventory account."

Fuel consortiums work closely with airports to negotiate land leases for fuel infrastructure. Most major airports have underground piping systems comprised of central transmission lines that branch into smaller hydrant systems located at each gate. "Many airports have areas that they would prefer to see certain infrastructure so it doesn't interfere with terminal or runway expansions," points out Southwest Airlines Director-Fuel Operations Tom McCartin. "We generally work out an agreement with the airport to build a fuel farm and select an operator for the facility. The consortium might propose five or seven or ten days of storage at a particular airport. That gives us an idea of how many tanks to build and how much funding we'll need."

Depending on the location, consumption rate and available storage, airlines could store enough fuel for two days or up to two weeks at an airport. "We develop all sorts of plans to protect infrastructure and expand upon it, taking into account supply disruptions and shortages and other issues," says Zak. "At Washington Dulles, we just built three huge tanks on the airport adjacent to our normal supply to secure capacity." Fuel at IAD comes up the pipeline from the Gulf Coast, where hurricanes and other supply disruptions have occurred. Consequently, many carriers have decided to expand storage capacity there to reduce vulnerabilities and ensure operations for an extended period without relying on pipeline shipments from the refineries.

Airports have a viable stake in the operations of airlines and generally have a strong funding capacity with access to low-cost capital. Often they reach financing agreements with carriers for construction projects. To help project fuel storage levels, airlines often use historical data based on past consumption and future forecasts of route structures and operations.

"I might buy 10,000 barrels of jet fuel and have it delivered to JFK or LAX or Denver," says Zak. "You have inventory accounts and your supply decreases as your aircraft takes fuel. So if you need 5,000 gallons today and 10,000 gallons tomorrow, they record it, fill your airplanes and deduct the 15,000 gallons from your inventory account. So obviously you need to replenish your supply."

In April, Massport began constructing a centerfield taxiway (aka Taxiway Mike) at Logan that is expected to enhance airfield safety and reduce queuing, fuel burn and emissions. Recommended by US FAA in 1993, the 2,834.6-m. parallel taxiway will be located between Runways 4L/22R and 4R/22L. Construction will begin at the north end of the airfield and move south toward 15R/33L. Project cost is about $43 million and work is slated for completion next spring.

"The taxiway will run right down the middle of our parallel runways," explains Freni. "These are our busiest runways, so the taxiway will increase our efficiency and speed at getting aircraft to takeoff areas and back to the terminals from landing areas. We expect to see a good deal of savings in fuel burn there."

Hartsfield-Jackson Atlanta International, currently the busiest airport by landing, takeoff and passenger traffic, opened a perimeter taxiway last year that has eliminated more than 500 runway crossings per day. Dallas/Fort Worth International, which sees some 1,800 runway crossings daily, is slated to open a perimeter taxiway this year. The taxiway will allow aircraft to taxi around the end of its seven active runways instead of waiting to cross them.

"Aircraft don't have to stop moving," explains Marchi. "There's an intermediate taxiway between the arrival and departure runways at both airports that allows aircraft to go right to end of runway and around the end of the departure runway. It seems a little counterintuitive, but you actually save fuel as opposed to sitting there and idling for six minutes waiting for clearance to cross."

Carriers with twin-engine aircraft often taxi on one engine to save fuel. A 737 burns about 3.7 gal. of fuel per min. when taxiing, according to Southwest Airlines Fuel Management VP Rob Myrben. "There's no one solution to saving fuel" he says. "You've got to take a broad approach. We try to single-engine taxi where appropriate. We take advantage of gate services as best we can, and use city power rather than run aircraft APUs."

Newark Liberty International has implemented CASL's realTimeFuel technology, a fuel inventory management and reporting system that offers real-time access to fueling operations and eliminates costs associated with printed tickets, fuel sheets and data handling in reconciliation systems. Developed by Commport Aerospace Services Ltd., the technology can track fuel volume activity from pipeline to cockpit. Digital level sticks in tanks monitor fuel volumes and tank levels. As aircraft are fueled, the system receives data from tankers, hydrants and hydrant carts and sends it to a central database where it is made available to airlines electronically.

According to CASL CEO David Ralph, realTimeFuel can save airlines about $300 per flight. After CASL demonstrated realTimeFuel at IATA's fuel forum in Istanbul last year, the company said it received numerous invitations from airports to make proposals to implement the technology.

"There is a tangible need for airports to deliver cost-effective solutions to their customers in 2008 and beyond," CASL Product Development Director Mike Robertson told this magazine in January. "RealTimeFuel provides the capability to give everyone in the fuel supply chain, whether it be the airport, the into-plane agent or the airline, the ability to deliver and realize these savings."