StacksVerified U.S. regulatory reference

33 CFR §183.538

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Each metallic fuel line connecting the fuel tank with the fuel inlet connection on the engine must:
  1. (a)Be made of seamless annealed copper, nickel copper, or copper-nickel; and
  2. (b)Except for corrugated flexible fuel line, have a minimum wall thickness of 0.029 inches.