If the 787 wings were aluminum, rather than composite, Boeing probably would have elected to have a fuel-inerting system for only the center fuel tank, Sinnett said.
The 787 inerting system will add about 200 pounds to each plane, or the equivalent of one passenger. At full power, it will draw about 40 kilowatts. Sinnett said the system operates automatically as a function of the flight profile and the electrical demands on the plane.
The system is also not "dispatch critical," Sinnett said. That means an airline could keep the jet in service for a period of time even if the inerting system malfunctioned.
One reason that airlines oppose fuel-inerting systems is a concern that they will add a layer of complexity that drives up maintenance costs and could keep a jet at the gate if the system were not working properly. Boeing is working with the FAA to allow a 787 to remain in service for up to 10 days if the fuel-inerting system should fail.
P-I aerospace reporter James Wallace can be reached at 206-448-8040 or .
787 FUEL SAFETY EFFORTS Boeing has developed a fuel-interting system for the 787 that reduces the level of oxygen in its fuel tanks to reduce the chance of an explosion
1) Air is drawn from a long tube with tiny holes in it that runs the length of the cargo bay.
2) The air goes through a compresser and is then filtered through a device that separates out the oxygen.
3) As fuel is used, nitrogen is pumped into the fuel tanks in the wings and the center fuel tank. The level of oxygen in the tanks would be too low to support a fire or explosion should there be an electrical spark, rendering any fuel vapors intert.
Source: The Boeing Co.
The inerting system that will be used on the 787 works pretty much the same way as one that is being tested on two 747-400s and two 737-700s that are in service with airlines and cargo operators.
More than 1o years after the TWA Flight 800 crash, the NTSB says that fuel tanks are just as flammable.
Nearly nine years after a fuel tank explosion caused the fatal crash of TWA Flight 800, safety officials say little has been done to reduce the flammability of vapors in aircraft fuel tanks.