CS 22.971  Fuel tank sump

CAA ORS9 Decision No. 1

(a) Each fuel tank must have a drainable sump with an effective capacity, in the normal ground and flight attitudes, of 0.10% of the tank capacity, or 120 cm³, whichever is the greater, unless – 

(1) the fuel system has a sediment bowl or chamber that is accessible for drainage and has a capacity of 25 cm³; 

(2) each fuel tank outlet is located so that, in the normal ground attitude, water will drain from all parts of the tank to the sediment bowl or chamber. 

(b) The drainage system must be readily accessible and easy to drain. 

(c) Each fuel system drain must have manual or automatic means for positive locking in the closed position.