CS 22.969  Fuel tank expansion space

CAA ORS9 Decision No. 1

Each fuel tank must have an expansion space of sufficient capacity, but of not less than 2% of the tank capacity, to prevent spillage of fuel onto the surfaces of the sailplane due to thermal expansion, sloping ground or any normal ground attitude or manoeuvre, unless the design of the venting system precludes such spillage. It must not be possible to fill the expansion space inadvertently with the powered sailplane in any normal ground attitude.