777-200LR Flight Test Journal: Archives

29 November 2005

Fueling the world record flight

Scott Fortman, 777-200LR propulsion program manager

Tracy Tweet, 777 fuel systems design lead

A lot of credit for the 777-200LR's record-distance flight between Hong Kong and London goes to the tremendous work done by the flight crew and people in the 777 flight test programs. Playing important roles, too, were this great airplane's technology, engineering and special features, such as the auxiliary fuel tanks. Getting the tanks ordered, installed and tested in time for the record flight had our team in Fuel Systems scrambling over the past year or so.

The 777-200LR Worldliner was meant from the beginning to have up to three auxiliary fuel tanks, but we put the system design on hold in mid-2004 until the market turned around and customers started ordering the extra tank option. Without the extra tanks, the -200LR carries about 47,890 gallons of fuel, each of the optional tanks adds 1,875 gallons. The tanks are designed to take up as little space as possible and not reduce the plane's cargo space any more than necessary.

About a year ago, the 777 program leadership approached us with the idea of setting a new non-stop distance record. But first they needed to know if we could get enough fuel on board since design work had stopped on the auxiliary tank system. Could we find something already available on the market and somehow make it work? Fortunately, the answer was "yes." We had the tank supplier, Marshall Aerospace, continue building two auxiliary tanks to have on hand for testing once the design work restarted. Then we worked with Marshall and our Structures group to get a third tank and all of the tank supports built in time. Now we had our tanks.

That, however, was just the start; it's a lot more than just sticking a few tanks in the cargo hold. Plumbing, wiring, a control system and other parts had to be installed or revised, which affected a lot of people in other design groups. Most of their design work was stopped, as well, and we didn't have time to do the full production design we had planned. We had to figure out a design and installation plan that would be temporary - enough for a safe auxiliary fuel system for several test flights and the world record attempt. We knew whatever we installed would come out when the plane went to 'refurb' and made ready for the customer.

By November 2004 we had a basic plan in place to get WD002 ready to set a world record in June, to coincide with the Paris Air Show. To make the deadline, the tanks and other hardware needed to be available and installed between March and May. We had to get everything functionally tested and lined up for WD002's first flight on May 21.

Since the auxiliary fuel system was 'temporary,' it wasn't installed with everything operating in a fully automatic mode; a lot of the valves had to be operated manually. After several successful test flights, we were confident the system was going to work well. A few weeks later the decision was made to move the record flight to the fall, in part to take advantage of more favorable wind and weather conditions. The rest, as they say, is now aviation history.

We were really impressed with the way everyone pulled together on the installation and other work necessary to make this happen. Considering the parts availability issues we had and the unusual production schedule and work flows, it was frustrating at certain points. There were several times when different teams could have thrown their hands up and said "We've had enough!" but they really were great and rolled with the punches and stuck with it. We wanted to show off a great airplane and 'going the distance' was a great way to do it.