Fuel tank vents and carburetor vapor vents.

CFR · 2024-01-01 · US · Title 14

(a) (1) The vents must be arranged to avoid stoppage by dirt or ice formation; (2) The vent arrangement must prevent siphoning of fuel during normal operation; (3) The venting capacity and vent pressure levels must maintain acceptable differences of pressure between the interior and exterior of the tank, during— (i) Normal flight operation; (ii) Maximum rate of ascent and descent; and (iii) Refueling and defueling (where applicable); (4) Airspaces of tanks with interconnected outlets must be interconnected; (5) There may be no point in any vent line where moisture can accumulate with the rotorcraft in the ground attitude or the level flight attitude, unless drainage is provided; (6) No vent or drainage provision may end at any point— (i) Where the discharge of fuel from the vent outlet would constitute a fire hazard; or (ii) From which fumes could enter personnel compartments; and (7) The venting system must be designed to minimize spillage of fuel through the vents to an ignition source in the event of a rollover during landing, ground operations, or a survivable impact. (b) (1) Each vent system must have means to avoid stoppage by ice; and (2) If there is more than one fuel tank, and it is necessary to use the tanks in a definite sequence, each vapor vent return line must lead back to the fuel tank used for takeoff and landing.

official document · source cfr-2024 · id 14:§ 29.975