Each fuel tank filler connection must prevent the entrance of fuel into any part of the airplane other than the tank itself. In addition—
[Reserved]
Each recessed filler connection that can retain any appreciable quantity of fuel must have a drain that discharges clear of each part of the airplane;
Each filler cap must provide a fuel-tight seal; and
Each fuel filling point must have a provision for electrically bonding the airplane to ground fueling equipment.