Chapter 5 - Fuel System Flashcards
What is the purpose of the fuel system?
To provide a positive flow of fuel to the 3 power plants and APU during all stages and conditions of flight
How many fuel tanks are there? - and name them
4 tanks
1, 2 & 3 - Main Tanks
4 - Transfer Tank
What bays are each tank located in?
Tank 1 - Bay 6
Tank 2 - Bay 3
Tank 3 - Bay 2
Tank 4 - Bay 1
What is the purpose of the fuel tank?
To hold fuel and provide a mounting for the fuel delivery, transfer and gauging components
What does Tank 4 provide?
Provides a back up fuel supply to No.1, 2 & 3 fuel tanks
How are the fuel tanks separated from the fuselage?
By a secondary structure, capable of absorbing local impact damage conditions
What is each tanks capacity?
Approximately 820kg pressure refuel
795kg gravity refuel
What other methods can be used to refuel?
Ferry Tank
HIFR
Air to Air
What is a Ferry Tank?
A large tank fitted to a pallet fastened to the cabin floor and is connected to the aircraft fuel system by a fuel feed pipe
What is used to ensure a positive fuel flow to the booster pumps?
A collector tank
What is on the canister assembly/ collector tank to ensure a positive supply of fuel? (2)
Flap Valves
Jet Pump
How does a jet pump operate?
Uses the booster pump to initiate the suction of fuel from the fuel tank to the collector tank via a venturi effect
What fuel tank supplies fuel to the APU?
No. 2 Fuel Tank
What is the purpose of the fuel delivery filtration system?
To maintain fuel cleanliness prior to entering the powerplant/ APU
What is the Merlin Fuel system dependent on?
Dependent solely on the anti-icing additives in the fuel as there is no anti-icing facility
How many booster pumps are there and where are they located?
6
2 each in Tanks 1, 2 & 3
How are the 2 booster pumps connected?
Via a manifold to provide a single positive feed to their respective engines
What does the booster pump manifold have incase of a double pump failure?
A suction pipe
What is at the base of the booster pump?
A strainer/ filter
Where is the distribution manifold located?
On the transmission deck, fwd of the No.1 EECU
What is the purpose of the distribution manifold?
Allows any engine to be cross fed with fuel from any main tank
Allows fuel supply to be shut off at the manifold
What type of pump is the APU pump?
Electrical pump
What are the 2 modes of operation for the transfer pumps?
Automatic and Manual
What type of valves are Transfer and Dump Valves?
Dual purpose valves
What do Transfer and Dump valves allow?
Allow fuel into the main takes
Allow fuel from the tanks to the gallery
At what point does tank 4 automatically transfer fuel into other tanks?
When the tank reaches 70% on the level float switch
Which tank does not have an external vent pipe on the left side?
Tank 4
What are the components of the vent system?
Cross-over vent pipes Air.no fuel valves Expansion Tanks Spill Sensors Anti-siphon valves Vent pipes with flame traps
What does the air/no fuel valve do?
Prevents fuel from entering the external pipelines
Allows residual fuel to drain from the vent pipes
What do expansion tanks do?
help correct fuel overspill problems during refuel operations
Contain baffles to prevent fuel surge through the vent system
What are Anti-siphon valves?
Act as non return valves due to differential pressure if the vent pipes fill with fuel
Creates a suction effect when the valve opens to stop fuel flow
Where are the external vent pipe exits located?
Sides of the cabin
How is the fuel system controlled?
Electronically from the cockpit
What is the FIEU and what does it do?
Fuel Indicating Electronic Unit
Monitors the signal from the probes and displays the information on the IDU
How many fuel gauging probes does each fuel tank have?
3
2 primary, 1 secondary
Where is the APU pump located?
port side, below the fuel manifold
