§29.1013 Oil tanks

(a) Installation. Each o il tan k installation m ust m eet th e req uirements o f CS 29.967. (b) Expansion space. Oi l t ank expansi on space must be provided so that – (1) Each o il tan k u sed with a reciprocating engine ha s an expansion space of not l ess t han t he great er of 10% of t he t ank capacity o r 1 .9 litres (0.42 Imperial gallon/ 0.5 US gallon), and each oil tank used with a turbine engine has an expansion space of not less than 10% of the tank capacity; (2) Each reserve oi l t ank not directly connected to any engine has an expansion space of not less than 2% of the tank capacity; and (3) It is im possible to fill the expansion space inadvertently with the rotorcraft in the normal ground attitude. (c) Filler connections. Each recessed oil tank filler connection that can retain any appreciable q uantity o f o il m ust h ave a drain that discharges clear of the entire rotorcraft. In addition – (1) Each oil tank filler cap must provide an oil-tight seal under t he pressure expect ed i n operation; (2) For Category A rotorcraft, each oil tank filler cap o r filler cap cover must incorporate features that provide a warning when caps are not fully lo cked or seated on the filler connection; and (3) Each oil filler must be marked under CS 29.1557 (c) (2). (d) Vent. Oil tanks m ust be vent ed as follows: (1) Each oi l t ank m ust be vented from the top part of the expansion space so that venting is effect ive under al l norm al fl ight conditions. (2) Oil t ank vent s m ust be arranged so that condensed water vapour that m ight freeze and obstruct the line cannot accum ulate at any point. (e) Outlet. There m ust be m eans to prevent entrance into the tank itself, o r in to th e tan k o utlet, of any object t hat m ight obst ruct t he fl ow of oi l through the system. No oi l t ank out let m ay be enclosed by a screen or guard that would reduce the flow of oil bel ow a safe val ue at any operat ing temperature. There must be a shutoff valve at the outlet of each oil tank used with a turbine engine unless t he ext ernal port ion of the oil system (including oil tank supports) is fireproof. (f) Flexible liners. Each flex ible o il tan k liner must be approved or shown to be suitable for the particular installation.