AMS 274 Turbines Unit 3 Exam Review (Hancock)
State three functions of the oil tanks overboard relief valve: - -1. Maintains positive
pressure
2. Vents to prevent tank failure
3. Allows depressurization of tank at shutdown
-What is the function of the oil tanks dwell chamber? - -Separates air from the oil (bleeds it
out from the scavenge system)
-What is the position of the internal valves of the pressurizing and vent valves when the
aircraft is on the ground? - -Aneroid valve is open
-What is the position of the internal valves of the pressurizing and vent valves when the
aircraft is at 20k ft? - -Aneroid begins to open at around 8000-10000 ft, and will be
completely closed at 20000 ft
-What is a "hot tank"? - -The cooler is located in the pressure subsystem
-What is a "cold tank"? - -The cooler is located in the scavenge system
-Explain trimming: - -Also known as tuning, is when you make adjustments to the fuel
control system for idle and max power (there are 2 adjustments)
-Explain the thermostatic valve position and flow of fuel and oil when the oil is cold in a
fuel/oil cooler: - -The thermostatic valve is open and ONLY fuel is flowing
-Explain the thermostatic valve position and flow of fuel and oil when the oil is hot in a
fuel/oil cooler: - -The thermostatic valve is closed and forces oil through the cooler with
the fuel (the two mix and oil heats the fuel)
-Oil jets: - -Fixed nozzles that apply constant flow to all the bearings (fixed nozzles used
for this reason)
-Chip detector: - -Checks for the presence of ferrous material due to internal breakdown
-What happens when ferrous pieces get into a chip detector? - -When chips get in they
attach to the magnet and complete the circuit to the electrode and cause a chip light to
illuminate in the cockpit
-Gas turbine engines require what kind of oil? - -Synthetic oil (cannot be interchanged
with reciprocating engine oil)
-When should the oil in turbines be serviced and why? - -Just after shutdown when the oil
is still warm so you don't over-service the system
State three functions of the oil tanks overboard relief valve: - -1. Maintains positive
pressure
2. Vents to prevent tank failure
3. Allows depressurization of tank at shutdown
-What is the function of the oil tanks dwell chamber? - -Separates air from the oil (bleeds it
out from the scavenge system)
-What is the position of the internal valves of the pressurizing and vent valves when the
aircraft is on the ground? - -Aneroid valve is open
-What is the position of the internal valves of the pressurizing and vent valves when the
aircraft is at 20k ft? - -Aneroid begins to open at around 8000-10000 ft, and will be
completely closed at 20000 ft
-What is a "hot tank"? - -The cooler is located in the pressure subsystem
-What is a "cold tank"? - -The cooler is located in the scavenge system
-Explain trimming: - -Also known as tuning, is when you make adjustments to the fuel
control system for idle and max power (there are 2 adjustments)
-Explain the thermostatic valve position and flow of fuel and oil when the oil is cold in a
fuel/oil cooler: - -The thermostatic valve is open and ONLY fuel is flowing
-Explain the thermostatic valve position and flow of fuel and oil when the oil is hot in a
fuel/oil cooler: - -The thermostatic valve is closed and forces oil through the cooler with
the fuel (the two mix and oil heats the fuel)
-Oil jets: - -Fixed nozzles that apply constant flow to all the bearings (fixed nozzles used
for this reason)
-Chip detector: - -Checks for the presence of ferrous material due to internal breakdown
-What happens when ferrous pieces get into a chip detector? - -When chips get in they
attach to the magnet and complete the circuit to the electrode and cause a chip light to
illuminate in the cockpit
-Gas turbine engines require what kind of oil? - -Synthetic oil (cannot be interchanged
with reciprocating engine oil)
-When should the oil in turbines be serviced and why? - -Just after shutdown when the oil
is still warm so you don't over-service the system
