Honda HondaJet HA-420 Pilots Operating Manual page 113

Honda Aircraft Company
HA-420 SYSTEMS
POM DESCRIPTION
Fuel is consumed from the fuselage tank until the level of fuel in the
fuselage tank reaches the water line of the level control float valve.
At that time fuel from the C/T tank is consumed until the fuel level in the
C/T tank drops below the level control float valve installed at the low
point in the C/T tank. This float valve then opens allowing the remaining
fuel in the fuselage tank and the trapped fuel in the line to drain into the
C/T and be transferred to the wing tanks. The fuel in the wing tanks is
consumed last as it drains or is pumped into the collector tank.
Fuel Venting System
The fuel venting system is symmetrical about the aircraft center line.
There are two ram air scoops located on the side of the wing to body
fairing to provide ram air pressure to the expansion space. The
expansion space is located within the fuselage bladder tank.
Vent lines connect the expansion space to all other tanks. A vent drain
valve is located in the carry-through tank at the lowest point of each vent
line system. It opens when fuel in the carry-through tank falls below the
level of the drain valve and allows trapped fuel or moisture in the vent
line to drain into the carry-through tank.
Vent Float Valves
Vent float valves installed in the wing and C/T tanks allow air to
evacuate the fuel tanks during refueling or climb, and to allow air to
enter the fuel tanks to replace consumed fuel. Two valves are installed in
each wing tank at inboard and outboard locations, and two valves are
installed in the C/T tank on the L and R sides. During refueling, the
rising fuel level pushes air into the vent lines. When the fuel level rises to
the actuating level of the float valves, the valves close to prevent any fuel
from entering the vent lines. During operation, as the fuel level in the
HJ1-29000-005-001
October 30, 2016 1-97
FOR TRAINING PURPOSES ONLY