M15

What does represent point 2 in the Joule-Bryton cycle?. Beginning of the combustion chamber, ambience temperature and pressure. Beginning of the combustion chamber, ambience temperature and high pressure. Beginning of the combustion chamber, increased temperature and high pressure.

In a gas turbine engine the cold section Which elements comprehends?. Air intake, compressor and turbine. Air intake and nozzle. Air intake and compressor.

In turboprop engines the exhaust gases: Partially participate to the thrust generation. do not influence the thrust. Participate actively to the thrust generation.

Which of the following is the definition of the thermodynamic efficiency?. The ratio between the net work and the ingoing heat. The product between the net work and the ingoing heat. The sum between the net work and the ingoing heat.

What kind of energy losses are considered for an actual cycle?. Mechanical losses of compressor and turbine and imperfect combustion. Mechanical losses of compressor and turbine, imperfect combustion and heat dispersion. Mechanical losses of compressor and turbine and heat dispersion.

Regarding the Geared Turbo Fan Engine: 50% decrement in the emission. save over 1 million Dollars per year per A/C from average flight cost. both are correct.

what the Geared Turbo Fan provide ?. Front fan and low Turbine operate with Different speeds. Front fan and low Turbine operate with the same speed. slow down the compressor speed to decrease the SFC.

Regarding the Geared Turbo Fan Engine: Dimensions of Low Pressure Turbine Reduced. Dimensions of High Pressure Compressor Reduced. Dimensions of High Pressure Turbine Reduced.

What does the turbo-prop reduction gear assembly include?. an independent control engine system. an independent lubrication system. an independent anti-icing system.

The turbo-prop reduction gear assembly includes: An independent hydraulic system. An independent lubrication system. An independent pneumatic system.

How is driven the propeller in a free-turbine engine configuration?. by a dedicated turbine through reduction gearing. by the same shaft (so, the spool) that drives the compressor. by the compressor.

Which is the main difference between single shaft and free-turbine engine?. it is the type of the propeller installed. it is the dimension of the engine compartment. it is the power transmission to the propeller.

What is the great advantage of a free turbine configuration?. it is the possibility to reduce torque loads during take off phase. it is the possibility to increasing torque loads during engine starting. it is the possibility to reduce torque loads during engine starting.

Where is included the safety coupling?. In the reduction gear assembly. In the turboprop FADEC. In the turboprop compressor.

Which is the overall ratio of reduction in two stage reduction gearbox?. typically equal to about 7-8 to 1. typically equal to about 5-6 to 1. typically equal to about 3-4 to 1.

Which is the output speed obtained by a typical integrated two-stage reduction gearbox for turboshafts?. 8000 RPM. 6000 RPM. 4000 RPM.

Which of the following sentences is correct considering a "Twin Pack" turboshaft engines?. they have an unique power shaft as input and an unique shaft as output. they have two engine power shafts as input and an unique shaft as output. they have two engine power shafts as input and two engine shafts as output.

Which is the spin range for the main rotor of the helicopter?. between 4000 and 6000 RPM. between 1000 and 3000 RPM. between 200 and 400 RPM.

Where the APU (Auxiliary Power Unit) air inlet is usually placed?. in the upper surface of the fin and tailplane. at the bottom of the fuselage. at the bottom of the cockpit.

Which is the basic element of an APU (Auxiliary Power Unit)?. a large single-shaft gas turbine engine. a small single-shaft gas turbine engine. small multi-shaft gas turbine engine.

What does it happen when the pilot begins the APU (Auxiliary Power Unit) start sequence?. the control box manage APU (Auxiliary Power Unit) starting sequence in order to begin the combustion process. the control box manage FADEC starting sequence in order to begin the combustion process. the control box manage starting sequence in order to begin the combustion process.

What kind of turbine is used for the APU?. Axial turbine. Centrifugal turbine. Annular turbine.

In how many way can be installed the gas turbine engine power plants?. two ways. one way. three ways.

How is generated the jet exhaust noise?. by the interaction of pressure fields and turbulent wakes. by the violent turbulent mixing of the inlet gases with the atmosphere. by the violent turbulent mixing of the exhaust gases with the atmosphere.

Which is the main function of firewalls?. to divide the wings from the engine. to separate the air intake area from the engine compartment. to insulate the engine compartment and prevent the spread of fire.

Where gas turbine engine can be installed?. Both the previous answers are correct. In the rear part of fuselage or buried inside the fuselage. Under the wings.

How is supplied the Fenwal sensing system?. with 28 Volt AC electrical power. with 50 Volt DC electrical power. with 28 Volt DC electrical power.

Which one is the universally adopted extinguish agent in all engines?. Tetrafluoroethylene. Halon 7349. Halon 1301.

What is the class A of classification of fires?. it is a combustion of a solid fuel. it is a combustion of a liquid fuel. it is a combustion of gas fuel.

Which of the following sentences is true considering the Kiddle continuous-loop detection system?. two wires are buried in a ceramic bead. two wires are buried in a metallic bead. three wires are buried in a ceramic bead.

What does hot section inspection include?. the whole compressor assembly. the air intake. the combustion chambers, the turbine assemblies and the exhaust section.

How is divided the maintenance of gas turbine?. Line and base maintenance. Outer and inner maintenance. Line and heavy maintenance.

What can be the meaning of low EPR reading?. Engine operational instability, excluding the surge. Internal damage, excluding an LP turbine failure. Rapidly-changing external conditions, such as inclement weather or bird ingestion.

When can the blade tips and concave surfaces be scanned with boroscope?. in the first pass. in the second pass. in the third pass.

What does cold section inspection include?. the combustion chambers. the air intake and the whole compressor assembly. the turbine assemblies and the exhaust section.

What is necessary to do in case of engine failure during the starting procedure?. Aborting the procedure and running a ventilation cycle to evacuate the waste of fuel and gas. Reducing progressively the engine RPM. Aborting the procedure.

Which are the typical symptoms of severe engine damage?. the combustion chamber temperature reaches 5000 K. EPR, N1, N2 and fuel flow will drop quickly. EPR, N1, N2 and fuel flow will drop quickly and EGT may rise momentarily.

What happens to main engine parameter in case of engine fire?. Thy are all low. They remain the same. They fluctuate.

Which is the method of evaluating vane surfaces?. to position the remote light behind the component. to position the remote light near enough the component. to position the remote light adjacent to a vane surface.

What is the consequence of an improper depreservation?. Has no consequences. Can cause problems in the next preservation treatment. Can cause malfunction and reliability lack of the engine.

When desiccants are pink?. When humidity is around 60%. When humidity is around 40%. When humidity is very low.

If engine transport is by boat or the engine must be stored for long periods, it is recommended to use: Metal container. Plastic container. Cardboard container.

Where anti-corrosive compounds are applied using a brush?. on every small part of the engine subjected to corrosion. on compressor inlet area. on the exhaust area.

What does it mean the acronym ECAM?. Electronic Centralized Aircraft Monitoring. Electronic Centralized Aircraft Maintenance. Electronic Crew Alerting Monitor.

What is TOT?. the temperature at the turbine outlet. the temperature at the exhaust nozzle inlet. the temperature inside the turbine measured at two significant stages.

Which is the correct tension and frequency of electric power that must be supplied to AC instruments?. 26V 400 Hz. 28V 400 Hz. 26V 200 Hz.

What is the basic functioning principle of thermocouple?. The interaction between two different metals. The interaction of three different metals. The interaction between two wires made of the same metal.

What is the EPR?. Is the ratio between the pressure at the engine inlet (Inlet Pressure, or IP) and the Jet Pipe Pressure (JPP). Is the ratio between the Jet Pipe Pressure (JPP) and the pressure at the engine outlet (Outlet Pressure, or OP). Is the ratio between the Jet Pipe Pressure (JPP) and the pressure at the engine inlet (Inlet Pressure, or IP).

When are used rapid response thermocouples?. Are used in low temperature discharge ducts. Are used in high speed discharge ducts. Are used in low speed discharge ducts.

How is obtained the hot junction of a thermocouple?. By winding the terminals. By welding the terminals. By brazing the terminals.

Where is used ECAM system?. Boeing Industries. Lockheed Martin industries. Airbus Industries.

How many kind of thermocouple is possible to recognize?. 2. 3. 4.

Which kind of current electrical power is used to supply the starter-generators?. direct current electrical power. pulsating current electrical power. alternating current electrical power.

How many categories of electric starters are there?. 4. 2. 3.

The ignition system and the starting system: Must operate alternately. Must operate separately. Must operate coordinately.

Which is the material used for the external body of an igniter plug?. Nickel. Chromium. Steel containing nickel and chromium.

Which is the primary function of ignition systems?. to create the mixture air-fuel. to open the ignition valve. to ignite the air-fuel mixture in the combustion chamber.

How much air is bleeded from the compressor for the engine air system?. 5-10%. 25-30%. 15-20%.

Which is the range of temperature and pressure of the air bled for air system for aircraft services supply?. 300-350 degrees Celsius and 275 kPa (40 PSI). 200-250 degrees Celsius and 275 kPa (40 PSI). 200-250 degrees Celsius and 295 kPa (50 PSI).

Typical values of temperature and pressure of the air bled for air system for aircraft services supply are: 200-250 °C and 40 psi. 250-300 °C and 60 psi. 300-350 °C and 80 psi.

How much air bleeded from the engine compressor is extracted from the main gas stream?. about 50%-60% of total mass airflow. about 30%-40% of total mass airflow. about 15%-20% of total mass airflow.

What can caused a hung start?. an insufficient starting power source. a compressor surge. a too high Exhaust Gas Temperature (EGT).

How is expressed the specific fuel consumption?. As the ratio between kg (or pounds) of fuel of net thrust or SHP. As kg or pounds of fuel per hour per kg (or pounds) of net thrust or SHP. As kg or pounds of fuel per kg (or pounds) of net thrust or SHP.

If the engine is not running Which is the value of the EPR?. 1. 0. not defined.

Could be specific fuel consumption (sfc) affected by ambient temperature changes?. No. Yes. Yes, but only at high altitude.

What does an unexpectedly high EPR indication mean?. an engine instability. the passage through the wall of sound. a malfunction in the fuel control.

What is the EPR?. The ratio of the pressure of the air as it comes out of the turbine to the pressure of the air as it enters the compressor. The ratio of the pressure of the air as it comes out of the compressor to the pressure of the air as it enters the turbine. The product of the pressure of the air as it comes out of the compressor to the pressure of the air as it enters the turbine.

What is MCT (also called MCN)?. Maximum thrust that can be demanded by the compressor from the engine without time limitation. Maximum thrust that can be demanded by the pilot from the engine with time limitation. Maximum thrust that can be demanded by the pilot from the engine without time limitation.

What does it means unexpectedly high EPR value?. Rollback or flameout, or internal damage such as a Low Pressure (LP) turbine failure. Engine operational instability, like surge, or rapidly changing external conditions, such as inclement weather or bird ingestion (FOD). Fuel control malfunction, or malfunction or clogging of the inlet air pressure probes.

Which one is the main purpose of the cone air inlet?. Use shock waves to pre-expand the air before entering the engine. Control the shock waves in the convergent section of the air inlet. To increase the turbulent regime of the air entering the engine.

What kind of air inlet is typically convergent?. Laminar Air inlet. Convergent air inlet. Turbulent air inlet.

What does the progressive increase in the cross-section of the air inlet cause?. a progressive increase in the dynamic pressure. a progressive increase in the static pressure. a progressive increase in the total pressure in ideal condition.

Which one is a function of the air inlet?. Make a uniform flow upstream of the compressor by decreasing the turbulence of the compressor inlet flow. Make a uniform flow upstream of the compressor by decreasing the turbulence of the turbine inlet flow. Make a uniform flow upstream of the compressor by increasing the turbulence of the compressor inlet flow.

Where are toroidal-shape air inlets installed?. on ramjets. on turboprops. on low BPR turbofans.

Where in an axi-centrifugal compressor is processed the biggest amount of air?. In the axial section. In the centrifugal section. In the diffuser.

Where are mostly used the axi-centrifugal compressors?. To equip the engines destined for small size fixed wing aircraft and rotary wing aircraft. To equip the engines destined for small size fixed wing aircraft only. To equip the engines destined for big size fixed wing aircraft and rotary wing aircraft.

Where is installed the distributor?. After the diffuser. Before the diffuser. Over the diffuser.

Why the compressor action is essential for the entire engine?. because the compressor is a rotating machine driven by the turbine. because the combustion chambers need a laminar flow for functioning. because the engine would generate no useful work if the air wasn’t compressed prior to combustion.

Which is the behaviour of the pressure along the compressor?. Quadratic. Non linear. Linear.

In Which direction is accelerated the air in a centrifugal compressor?. Radial Direction. Axial Direction. Tangential Direction.

Where in an axi-centrifugal compressor is obtained the highest compression ratio?. In the axial section. In the diffuser. In the centrifugal section.

What is the stator in an axial compressor?. The fixed component. The element that mostly increase the pressure. The movable component.

Who can perform the dynamic balance of a fan?. The manufacturer. A part 145 category A. A part 145 category D.

When air-to-fuel mixture is said to be "rich"?. when there is too much air and too little fuel. when the stoichiometric ratio is equal to 1. when there is too little air and too much fuel.

What is the role of the primary flow in a combustion chamber?. Permits the flame plume length to be controlled and full fuel combustion to be achieved. Has an active role in the combustion. Cools the flow of hot gases by dilution.

What can cause the flame-out?. too high speed of the primary air flow. combustion chamber manufacturing imperfections. too low speed of the tertiary flow.

Which is the function of the secondary flow in a gas turbine combustion chamber?. it cools the hot gases in the dilution zone. it supplies the combustion flame with pure oxygen. it makes the flame steady and control its length.

How action turbine blades are putted in rotation?. By the compression of the gases. By the expansion of the gases. By the impact of the gases.

Where is located the high pressure turbine in a typical jet engine turbine configuration?. before the nozzle inlet section. immediately after the combustion chambers. in the central part of the turbine assembly.

Where is located the high pressure turbine in a typical jet engine turbine configuration?. in the central part of the turbine assembly. immediately after the combustion chambers. before the nozzle inlet section.

What does correspond to a degree of reaction = 1?. Reaction turbine. Impulse turbine. Impulse-reaction turbine.

How is called the constant creep stage?. secondary stage. tertiary stage. primary stage.