Oil tanks.

CFR · 2024-01-01 · US · Title 14

(a) (b) (1) Each oil tank used with a reciprocating engine must have an expansion space of not less than the greater of 10 percent of the tank capacity or 0.5 gallon, and each oil tank used with a turbine engine must have an expansion space of not less than 10 percent of the tank capacity. (2) Each reserve oil tank not directly connected to any engine may have an expansion space of not less than two percent of the tank capacity. (3) It must be impossible to fill the expansion space inadvertently with the airplane in the normal ground attitude. (c) (d) (1) Each oil tank must be vented from the top part of the expansion space so that venting is effective under any normal flight condition. (2) Oil tank vents must be arranged so that condensed water vapor that might freeze and obstruct the line cannot accumulate at any point. (e) (f)

official document · source cfr-2024 · id 14:§ 25.1013