FAA issues special conditions for Boeing 777-9 fuel tanks

FAA, leveraging similar requirements issued more than a decade ago for the Boeing 787, has issued special conditions Boeing must follow to demonstrate the 777-9’s composite fuel tanks can withstand tire debris impact. The FAA requirements dictate that “tire-debris impact to any fuel tank or fuel-system component, located within 30 deg. to either side of wheel rotational planes, may not result in penetration or otherwise induce fuel-tank deformation, rupture (e.g., through propagation of pressure waves), or cracking sufficient to allow a hazardous fuel leak.” Testing must be done using a tire debris fragment that is 1% of the tire mass, and the fragment load must be “distributed over an area on the fuel tank surface equal to 1.5% of the total tire tread area,” FAA said. <br/>