14 CFR § 121.1119 - Fuel tank vent explosion protection.
(a)Applicability. This section applies to transport category, turbine-powered airplanes with a type certificate issued after January 1, 1958, that have:
(1) A maximum type-certificated passenger capacity of 30 or more; or
(2) A maximum payload capacity of 7,500 pounds or more.
(b)New production airplanes. No certificate holder may operate an airplane for which the State of Manufacture issued the original certificate of airworthiness or export airworthiness approval after August 23, 2018 unless means, approved by the Administrator, to prevent fuel tank explosions caused by propagation of flames from outside the fuel tank vents into the fuel tank vapor spaces are installed and operational.