§27.971 Fuel tank sump

(a) Each fuel tank must have a drainable sump with an effective capacity in any ground attitude to be expected in service of 0.25% of the tank capacity or 0.24 litres (0.05 Imperial gallons/one sixteenth US gallon), whichever is greater, unless: (1) The fuel system has a sediment bowl or chamber that is accessible for preflight drainage and has a minimum capacity of 30 ml (1 ounce) for every 76 litres (16.7 Imperial gallons/20 US gallons) of fuel tank capacity; and (2) Each fuel tank drain is located so that in any ground attitude to be expected in service, water will drain from all parts of the tank to the sediment bowl or chamber. (b) Each sump, sediment bowl, and sediment chamber drain required by the paragraph must comply with the drain provisions of CS 27.999(b).