§27.1013 Oil tanks

Each oil tank must be designed and installed so that – (a) It can withstand, without failure, each vibration, inertia, fluid, and structural load expected in operation; (b) (Reserved) (c) Where used with a reciprocating engine, it has an expansion space of not less than the greater of 10% of the tank capacity or 1.9 litre (0.42 Imperial gallon/0.5 US gallon), and where used with a turbine engine, it has an expansion space of not less than 10% of the tank capacity. (d) It is impossible to fill the tank expansion space inadvertently with the rotorcraft in the normal ground attitude; (e) Adequate venting is provided; and (f) There are means in the filler opening to prevent oil overflow from entering the oil tank compartment.