Station 4
Station 4:Left Side of Engine(Left Engine Bay)
(1)Super-emergency Solenoid Valve:If one engine fails and the torque difference ΔC between two engines exceeds 25% in flight,it will be connected to supply super-emergency fuel.The corresponding super-emergency power warning indicator on top of the EPD will light up at the same time.
Key Points to Check:appearance,installation,cable plug(s),cable(s)and leakage.
(2)Air Bleed Valve:It is opened during engine start process to adjust air inflow and prevent engine surges.
Key Points to Check:appearance,installation,cable plug(s)and cable(s).
(3)Start Solenoid Valve RDK-16:It is a fuel injector solenoid valve that provides fuel to the combustion chamber at the initial phase of the start-up process.When the fuel pressure reaches 0.24MPa(2.4bar),it begins to inject air instead of fuel.
Key Points to Check:appearance,installation,cable plug(s)and cable(s).
(4)Engine Oil Temperature Switch HJK-3:It lights up warning indicator“ENG.1”when the oil pressure drops below 1.3bar.
Key Points to Check:appearance,installation,cable plug(s),cable(s)and leakage.
(5)Engine Oil Pressure Sensor CY-YZ-0101-0.8L:The piezoresistive sensor contains a bellow connected to induction coils.It measures the oil pressure of each engine.The measurement range of pressure is 0-0.8MPa.The data will be transmitted to the EPU for processing and display.
Key Points to Check:appearance,installation,cable plug(s),cable(s)and leakage.
(6)Ignition Plug:It ignites the mixture of fuel and air.
Key Points to Check:appearance,installation and cable(s).
(7)Metal Chip Detector:It monitors the degree of abrasion in the bearing cavities of the engines.When excessive metal chips attracted fill the loop gap,the circuit will be connected and the indicator in the cockpit will light up to warn the flight crew.
Key Points to Check:appearance,installation,cable plug(s),cable(s)and leakage.
(8)Nf Sensor GZ-20:It measures the rotation rate of the free turbine and transmits the data to the EPU for engine power loss warning.
Key Points to Check:appearance,installation,cable plug(s),cable(s)and leakage.
(9)Overspeed Cut-off Solenoid Valve:When Nf is over 123.1%+2.5% of the rated value,the two sensors will detect the overspeed and the valve will shut down the engine.
Key Points to Check:appearance,installation,cable plug(s),cable(s)and leakage.
(10)Overspeed Sensor:It senses Nf,sends overspeed warning signals and shuts down the engine.
Key Points to Check:appearance,installation,cable plug(s),cable(s)and leakage.