How can the Helo be refueled?
What are some of the fuel systems capabilities?
Capable of pressure refueling, gravity refueling, and Helicopter In Flight Refueling (HIFR)
It has provisions to prime the engines, dump fuel, indicate quantity, and display low fuel levels
How is fuel supplied to the engines
Fuel is drawn up by the engine driven fuel boost pump, then pumped through the engine fuel filter to the HMU, which will route fuel through the oil/fuel heat exchanger to the ODV and finally the engine
What can cause the fuel press light to appear?
It could indicate a malfunction of the engine driven boost pump, or an air leak in the system
What is a fault of the fuel filters?
The fuel filters are not sensitive to water contamination. Water in the fuel could cause fluctuations/surges in one or both of the engines without any associated fuel filter press or bypass lights
Which positions do the fuel selector leavers have and what do they mean?
OFF, DIR, XFD
The valves are closed
Fuel is coming from the respective cell
Fuel is coming from the opposite cell
How do you work the fuel priming system?
Placing the switch to FUEL PRIME, will open both engine shut off valves and allow individual engine priming with the PCL in lockout
Placing the FUEL PUMP switch to APU BOOST will open the APU fuel shut off valve and activate the prime boost pump
(There is a Checklist in the PCL)
Whats the Main fuel tank Capacity?
Where is the internconnect?
The tanks can hold 590gal (usable) or 4012lbs if fueled with JP-5
The tanks main cell interconnect level is approximately 270-600lbs per side
What components does the left tank have?
The right tank?
Single point refuel/defuel, gravity refuel, HIFR, 2 high level shut-off floats, a check valve, a sump drain, and a vent
Two check valves, a sump drain, a vent, an APU fuel line, and the fuel dump system
Describe the Auxiliary tanks
What is thier capacity?
External fuel tanks may be installed on the two inboard pylons. They are crashworthy, ballistically hardened tanks with self sealing break away valves to prevent fuel spillage
They are either 120 or 113 gal capacities
How fuel quantity measured in the aux tanks?
The fuel level of each aux tank is internally monitored by a single gauge probe. A Low level Thermistor sensor is exposed when the tank is empty
How is fuel transfered from the Aux tanks to the main?
A dual transfer/dump pump and dual shutoff valves help transfer fuel to the main tank. The two pumps alternate every time the system is activated.
If one pump of shutoff valve fails, the remaining pump will still be able to transfer fuel
What controls the fuel transfer system?
How does it do so and when will it start to transfer fuel?
The Fuel Management Control Panel (FMCP) will control when fuel is transferred to the main tank or when fuel is routed to the aux tank for refueling.
Selecting TRANSFER/MANUAL OVRD will allow the pilot to manually transfer fuel to the main tank. When set to AUTO, fuel will automatically transfer to the main tank at 2640lbs of fuel
What hppens if the right tank fills faster than the left?
Because the shut off floats are in the left tank, if the vent if clogged and air is unable to escape the right tank will continue to fill and will not automatically stop refueling. This will lead to the right tank bursting.
If one tank fills faster than the other closely monitor the fuel quantity gauges and stop transferring fuel before the right cell is full (~1700lbs)
When can you do unmonitored fuel transfers?
Do not initiate unmonitored fuel transfers from the aux to the main, until the main tank is below 3,200lbs
When should you execute the manual fuel transfer check?
When the main fuel tank capacity has decreased approximately 300lbs, check manual fuel transfer to ensure proper transfer
How can you jettison the Aux tanks?
Whats the note associated?
External tanks can be jettisoned individually or simultaneously via either all stores jettison or selective jettison
Aux tank jettison is inhibited when there is less than 40gal of fuel (~272lbs) in the aux tanks. Because the fuel gauge for the aux tank reads in 50lb increments, if you are jettisoning the tank and it indicates below 300lbs, selective jettison should be used.
When does the FMCP automatically begin to move fuel from the aux to the main?
When the main tank depletes to 2640 lbs
In what sequence do the main tanks refuel/defuel?
The main tank is filled first, then the right external, then the left external
Fuel will be taken first from the main tank, then the left external then the right external (opposite)
What do the Precheck valves do?
What if the the FMCP is malfunctioning and activating them?
What if the valves are malfunctioning?
The precheck switches and valves allow you test the auto fuel flow securing logic. The valves can be tested inside of the cockpit or outside at the refuleing station.
If the FMCP is causing activation of the precheck valves you will be unable to pressure refuel, however pulling the FUEL MGMT Circuit breaker will allow you to continue.
If one precheck valve fails you are still able to safely take on fuel. If both valves fail, then fuel flow will not automatically stop, the pilot will need to closely monitor fuel level to ensure there is no damage done to the tanks.
How is the main tank fuel quantity measured?
Each fuel cell has a capacitance type fuel probe, which uses fuel as a dielectric in order to measure the weight of the fuel and display it in the cockpit.
Two separate and independent fuel low level sensor will illuminate the FUEL LOW caution when fuel in each cell reaches 300lbs. the caution may illuminate and extinguish as fuel washes on and off the sensors.
Whats the fuel dump rate?
Minimum of 800lbs per min
How do you initiate fuel dumping?
What if you are on the ground?
(THERE IS A CHECKLIST FOR THIS) Fuel dumping is activated by the FUEL DUMP switch on the lower console. When activated both transfer/dump pumps are energized and fuel is dumped overboard until the low level sensor is activated (approximately 300lbs each side)
With the FMCP set to TRANSFER/MANUAL OVRD will allow dumping from the external tanks as well
Fuel dump is NOT protected by the Weight-On-Wheels Switch
Describe the refueling system
A pressure port is supplied for standard 55psi refueling on the ground with or without electrical power.
It will refuel the main tank first, then the right external, then the left external
What makes up the HIFR system and how does it work?
What is it good for besides in flight refueling?
There is a wiggins quick disconnect, a pressure refueling fitting, a precheck switch and a 5 element GO/NO-GO cannister.
The GO/NO-GO cannister will only allow acceptale fuel to pass (so it will filter particulate AND water)