Storage

The storage system stores a sufficient quantity of fuel for normal helicopter operation. It has a filler port to fill it with fuel. It has vents to the atmosphere that prevent pressurization that could damage the fuel cell and the helicopter structure, and also the fuel cell from collapsing when the fuel level changes with temperature and normal operation. The vents have rollover valves that prevent the fuel from escaping through them if the helicopter ever rolled over during a crash or ground operations. It has a drain to collect a sample of fuel to examine it for the presence of contaminants such as water, and to remove the remaining fuel when the storage system is defueled.

The storage system consists of the components that follow:

• Fuel cell

• Filler cap

• Expansion plate

• Access cover plate

• Forward vent

• Forward rollover valves

• Aft vent

• Aft rollover valve

• Drain port

• Fuel tank drain line

• Fuel filler retainer

• Fitting, forward vent

• Vent adapter

Fuel cell

The fuel cell is a bladder type container and is crash resistant. It is located under the baggage compartment and has a usable capacity of 84.85 U.S. gallons (321.2 Liters) of fuel and maximum fuel capacity of 86.1 U.S. gallons (325.9 Liters) of fuel. It has an integral expansion space at its left-front upper end. The filler port is located on the expansion space under an access panel on the left side of the helicopter. The bottom of the fuel cell is canted towards the center to keep the unusable fuel to minimum. A sump at the bottom-center of the fuel cell collects water, when present. Foam packings around the fuel cell prevent it from chafing against the structure of the fuel cell compartment. Hook-and-pile tapes on the sides of the fuel cell attach it to hook-and-pile tapes on the walls of the fuel cell compartment.

Filler cap

The filler cap closes the filler port. It prevents the stored fuel from escaping, and permits easy refueling.

Expansion plate

The expansion plate gives access to the inside of the fuel cell. It provides mounting points for the forward vent fitting, feed line fitting, and engine drain fitting. It is located on top of the expansion space and provides support through the expansion tabs.

Access cover plate

The access cover plate gives access to the inside of the fuel cell. It provides mounting points for the fuel indicating and the aft rollover valve. It is located on top in the center of the fuel cell and provides support through the support brackets.

Forward vent

The forward vent equalizes the pressure inside the fuel cell with the ambient atmospheric pressure. It is connected between the forward rollover valves and the vent adapter.

Forward rollover valves

The forward rollover valves block the passage of fuel in a rollover. They are connected between the forward vent fitting and the forward vent.

Aft vent

The aft vent equalizes the pressure inside the fuel cell with the ambient atmospheric pressure. It is connected between the aft rollover valve and the vent adapter.

Aft rollover valve

The aft rollover valve blocks the passage of fuel in a rollover. It is located aft of the access cover plate and connects to the aft vent.

Drain port

The drain port is a quick disconnect that lets you connect a suction device to retrieve a sample of fuel. It is located on the expansion space next to the filler port.

Fuel tank drain line

The fuel tank drain line gets the fuel sample from the lowest possible location of the fuel cell. It is connected between the drain port fitting and the sump.

Fuel filler retainer

The fuel filler retainer surrounds the filler port and attaches the fuel cell to the structure.

Fitting, forward vent

The forward vent fitting is the mounting location for the forward rollover valves. It is located outboard on the expansion plate.

Vent adapter

The vent adapter combines the forward and aft vents into a single outlet. It is located under the helicopter mid-fuselage with its open end outside.

Operation

The fuel cell is filled with fuel by gravity through the filler port.

Suction is applied to the drain port to collect a sample of fuel from the sump at the bottom-center of the fuel cell. If the sample shows that there is water in the fuel cell, the drain port lets the operator remove it by collecting samples until there is no water present.

The vents let outside air enter the fuel cell and take the place of the pumped fuel, preventing the fuel cell from collapsing. They also prevent the build up of pressure when the fuel expands with temperature variations that could damage the fuel cell and the helicopter structure.

If the helicopter ever rolled over, the balls in the rollover valves will block the vents, preventing the fuel from spilling through the vent lines and getting to an ignition source.