In addition to providing 'customer' bleed for aeroplane systems air may be bled from compressors of a turbofan engine to increase stall margin ?
Exercise > Manual
One reason to fit a tip shroud to a turbine blade is to ?
The most important oil system instrument indication during gas turbine engine start is ?
Turbine blade stages may be classed as either 'impulse' or 'reaction' in an impulse turbine stage The pressure drops across stator blades remains constant across rotor blades, pressure rises across stator blades remains constant across rotor blades, pressure remains constant across stator blades drops across rotor blades, pressure remains constant across stator blades rises across rotor blades. nozzle guide vanes = stator. the pressure drops across stator blades remains constant across rotor blades. 
When a gas turbine engine fitted with can type combustion chambers A total of only two igniters are usually fitted since chambers are inter connected, each chamber has its own igniter, each chamber fitted with one igniter one glow plug, each chamber fitted with two igniters. Most gas turbine engines only have two igniters typically located diagonally opposed, in fact engine would probably start quite readily with only one operating, however, because there are only two, another means of passing starting flame between combustion chambers has to be found, this the interconnector. 
The purpose of gas turbine engine trending To enhance maintenance planning detect anomalies, to collect metal particles from oil system, to assess engine condition using non destructive inspection, to obtain a timely indication when an engine requires to be shut down due to problems. Engine trending, performance analysis, monitoring diagnostics permit to enhance maintenance planning to detect anomalies. 
The flexible take off mode 1 can be used only if engines are recent2 reduces engine wear3 can be used in situations where take off can be executed without need full engine power4 can only be used with an auto throttlethe combination that regroups all of correct statements 2, 3,, 2, 3,, 4, 2, 3, 4. Question Protection and Detection Systems 35 Answer 8
Concerning flexible take off mode temperature selected in fms Higher than ambiant airfield temperature, in order to achieve a reduced power setting, lower than ambiant airfield temperature, in order to achieve a reduced power setting, higher than ambiant airfield temperature, in order to achieve an increased power setting, lower than ambiant airfield temperature, in order to achieve an increased power setting. extract from boeing fcom (flight crew operations manual) assumed temperature reduced thrust regulations permit use of up to 25% takeoff thrust reduction operation with assumed temperature reduced thrust. use of assumed temperature reduced thrust not allowed with anti skid inoperative or on runways contaminated with standing water, ice, slush, or snow. use of assumed temperature reduced thrust not recommended if potential windshear conditions exist. a takeoff thrust less than full rated thrust may be achieved using an assumed temperature that higher than actual temperature. Question Protection and Detection Systems 35 Answer 9
One reason to fit a tip shroud to a turbine blade to Reduce blade vibrations limit marginal leaks, provide a seal the cooling airflow, reduce turbine temperatures, prevent blade creep. The shrouded blades form a band around perimeter of turbine which serves to reduce blade vibrations. the shrouds improve airflow characteristics increase efficiency of turbine. the shrouds also serve to cut down gas leakage around tips of turbine blades. Question Protection and Detection Systems 35 Answer 10
On a high pass ratio fan engine reverse thrust achieved reversing Only direction of fan airflow, only direction of exhaust gas flow, direction of rotation of fan, direction of both exhaust gas flow (hot stream) the fan airflow (cold stream). On high bypass turbofan engines, reverse thrust achieved reversing only direction of fan airflow in order to save costs mass. it not impossible to reverse hot exhaust gas, but it complex. the gain in reverse thrust will be less than 20% an increase in maintenance costs a higher inflight consumption due to weight of system. Question Protection and Detection Systems 35 Answer 11
If an abortive start hung start occurs when starting a gas turbine engine correct action to Shut down engine, select other igniter system, move thrust lever forward to increase fuel flow, activate both igniter systems. Question Protection and Detection Systems 35 Answer 12
Compressor surge may be controlled means of Bleed valves, a pressure drop control orifice, fixed inlet guide vanes, a variable metering orifice. Question Protection and Detection Systems 35 Answer 13
The use of igniters in a gas turbine engine required 1 throughout operating range of engine2 during engine acceleration3 on ground starts4 in flight relights5 during in flight turbulence6 under heavy rains or icing conditionsthe combination that regroups all of correct statements 3 only, 2, 3, 2 only. Normally, in flight, no igniters are in use as combustion self sustaining. during engine start for take off landing, igniters are in use. you have to use igniters in case of moderate or severe precipitation, turbulence or icing, or an in flight relight. Question Protection and Detection Systems 35 Answer 14
Vibration sensors are used in a gas turbine engine to indicate Imbalance of one or both of spools, that there too much free movement of engine strut (pylon), that tip clearance of turbine blades has decreased below a minimum value, bearing problems only. Question Protection and Detection Systems 35 Answer 15
The fan of a turbo fan engine driven The lp turbine, hp turbine, hp compressor through reduction gearing, airflow drawn across it the hp compressor. Question Protection and Detection Systems 35 Answer 16
Regarding a jet engine i the maximum thrust increases as pressure altitude decreases ii the specific fuel consumption increases slightly as pressure altitude decreases at constant tas I correct, ii correct, i incorrect, ii correct, i correct, ii incorrect, i incorrect, ii incorrect. jet engines are more efficient at higher altitudes because less fuel needed a given thrust, due to reduction in lift drag, lower temperatures through inlet cause a significant reduction in specific fuel consumption, up to tropopause. specific fuel consumption the amount of fuel burnt per unit of thrust. for jets, it reduces with altitude up to tropopause. Question Protection and Detection Systems 35 Answer 17
One of causes of high oil temperature in a gas turbine engine at constant power setting Malfunction of heat exchanger, unusually high scavenge pump oil flow, high oil pressure, high outside air temperature. the fuel/oil heat exchanger located in tanks. it cools oil heats fuel, so if at constant power setting you have a high oil temperature, it may come from a malfunction of heat exchanger. Question Protection and Detection Systems 35 Answer 18
Given following information about an aeroplane with a turbojet engine mass air flow 50 kg/s tas 90 m/s exhaust nozzle gas velocity 150 m/s exhaust nozzle static pressure1050 hpa ambient static pressure 1000 hpa cross sectional area of nozzle 0 10 m net engine thrust equals Jaredleto the formula required to answer this question is total thrust = mass thrust + pressure thrust or t = m(vj vv) + a(pj p0) where m = mass air flow, vj = exhaust velocity, vv = tas, a = exhaust cross section area, pj = exhaust static pressure and p0 = static ambient pressure. in this instance, pressures are given in hpa, need to be converted to n/sq m. therefore, t = 50 (150 90) + 0.1 (105000 100000), which gives answer of 3500 n. Question Protection and Detection Systems 35 Answer 19
A turbofan engine with an inlet air mass flow of 1000 kg/s and a bypass mass flow of 889 kg/s has a bypass ratio Of 8., of. 2, of 2. 2, of7. 2 1000 889 = 111 889 / 111 = 8.01 bypass ratio = bypass mass flow / hp compressor mass flow Question Protection and Detection Systems 35 Answer 20
Exhaust gas temperature sensing usually taken Between gas generator turbine the free power turbine, at outlet from combustion chamber, after free power turbine, between stages of gas generator turbine. Question Protection and Detection Systems 35 Answer 21
Flat rated jet engines are designed to provide constant maximum take off thrust up to a certain level of Ambient temperature, ambient pressure, engine pressure ratio, pressure altitude. the term flat rating so called because of flat nature of thrust versus ambient temperature curve. the curve shows that from lowest operating temperature possible to specified temperature, engine produces full thrust. above this temperature, full thrust will not be permitted. a 'flat rate turbofan engine controlled in such a way that at constant ambient air pressure there no variation of take off thrust with air temperature up to some specified temperature limit. above that limit engine operates in such a way that either fan speed or compressor speed constant or turbine inlet temperature constant and in either case thrust then decreases with increasing temperature. Question Protection and Detection Systems 35 Answer 22
Engine temperature limitations of a gas turbine engine are usually imposed due to temperature limitations on Turbine section, compressor section, casing of combustion chamber, jet pipe. Question Protection and Detection Systems 35 Answer 23
For a fan jet engine by pass ratio the External airflow mass divided the internal airflow mass, internal airflow mass divided the external airflow mass, internal airflow mass divided the fuel flow mass, fuel flow mass divided the internal airflow mass. bypass ratio = bypass mass flow / hp compressor mass flow. by pass mass flow the external airflow. hp compressor mass flow the internal airflow mass. Question Protection and Detection Systems 35 Answer 24
If main oil filter of a gas turbine engine becomes clogged oil to main bearings still assured Because oil filter bypass valve opens, because fuel upstream of oil filter will be mixed with oil to allow easier passage through filter, if a higher engine rpm selected to increase oil pressure, if breather pressure in main compartments increased to ensure positive lubrication of bearings. Question Protection and Detection Systems 35 Answer 25
In a free turbine engine energy delivered the free turbine stages Is dependent on rotational speed of gas generator, used to drive compressor the main rotor gearbox, not connected with rotation speed of generator, used to drive compressor only. julien35 from bristol book 'free power turbine engine the mechanical link between gas generator the propeller turbine removed, so each element free to rotate at its optimum spee. yes, but read question carefully... it talk about the energy delivered the free turbine stages. if gas generator does not rotate, free turbine stages will delivered 0 energy... if free turbine stages deliver full thrust, it possible only with a high rotational speed of gas generator. so energy delivered the free turbine stages dependent on rotational speed of gas generator. Question Protection and Detection Systems 35 Answer 26
Which statement correct a gas turbine engine with a constant speed propeller and free power turbine when power setting increased i the hp spool speed increases ii the egt increases I correct, ii correct, i correct, ii incorrect, i incorrect, ii incorrect, i incorrect, ii correct. Hp spool speed, egt gas generator speed all increase a gas turbine engine with a constant speed propeller free power turbine, when power setting increased. Question Protection and Detection Systems 35 Answer 27
Which statement correct a gas turbine engine with a constant speed propeller and free power turbine when power setting increased i the gas generator speed increases ii the egt increases I correct, ii correct, i correct, ii incorrect, i incorrect, ii incorrect, i incorrect, ii correct. Hp spool speed, egt gas generator speed all increase a gas turbine engine with a constant speed propeller free power turbine, when power setting increased. Question Protection and Detection Systems 35 Answer 28
The bypass ratio i the ratio of bypass air mass flow to hp compressor mass flow ii can be determined from inlet air mass flow and hp compressor mass flow I correct, ii correct, i correct, ii incorrect, i incorrect, ii correct, i incorrect, ii incorrect. bypass ratio = bypass mass flow / hp compressor mass flow. the bypass ratio can be determined from inlet air mass flow the bypass mass flow. Question Protection and Detection Systems 35 Answer 29
The bypass ratio i the ratio of inlet air mass flow to hp compressor mass flow ii can be determined from inlet air volume flow and hp compressor volume flow I incorrect, ii incorrect, i correct, ii incorrect, i incorrect, ii correct, i correct, ii correct. bypass ratio = bypass mass flow / hp compressor mass flow. the bypass ratio can be determined from inlet air mass flow the bypass mass flow, not volume. Question Protection and Detection Systems 35 Answer 30
Compressor stall in a gas turbine engine Can be caused an axial airflow velocity that low relative to rotor speed, does not occur with well designed compressor blades, unlikely to occur in a compressor with many stages, only occurs during engine start up. like stall of a wing, compressor stall caused a breakdown of airflow. if your wing suitable high speed, you fly at low speed large angle of attack, stall most likely to occur. a compressor stall most likely to occur when air flow stagnates in rear stages of compressor. a compressor blade hitting oncoming airflow at an angle of attack that determined a combination of rotational speed the incoming airflow. when incoming speed low angle of attack will be high. when angle of attack gets too high blade stalls. so when axial flow in a compressor backs up blades stall (pressure increase in rear stages this slows down flow). you can prevent this dumping some late stage air to atmosphere (via bleed valves). Question Protection and Detection Systems 35 Answer 31
The air flow passages between adjacent axial compressor rotor blades are divergent but absolute exit velocity higher than absolute entry velocity of rotor this because Part of compressor work delivered to air converted into kinetic energy, it a constant temperature process, compressor rotational velocity slows down air flow, gas expands between blades. compression of hot gas in rotor followed an expansion before entering stator. Question Protection and Detection Systems 35 Answer 32
A twin spool gas turbine engine one in which Lp turbine drives lp compressor the hp turbine drives hp compressor, lp compressor drives hp compressor, turbines are free to rotate at speeds that differ from their associated compressors, lp turbine drives both lp compressor the hp compressor. Question Protection and Detection Systems 35 Answer 33
When combustion gases pass through a turbine Pressure drops, pressure rises, axial velocity of flow decreases, temperature increases. Question Protection and Detection Systems 35 Answer 34
The most common extinguishing agent used in gas turbine engine fire protection systems A liquid halogenated extinguishing agent pressurized gas (typically nitrogen), water, co2, powder. Question Protection and Detection Systems 35 Answer 35
When a part of a continuous loop fire detection system heated 1 its resistance decreases 2 its resistance increases 3 leakage current increases 4 leakage current decreases the combination regrouping all correct statements Question Protection and Detection Systems 35 Answer 36
A fault protection circuit in a fire detection system will Inhibit fire detector when detection line connected to ground, activate an alarm in cockpit in landing gear bay ground crew, activate fire detection system when detection line connected to ground, automatically initiate apu shutdown fire extinguisher striker activation in event of fire. A fault protection circuit in a fire detection system will inhibit fire detection when detection line connected to ground. so, if a fire detection system with no fault protection has single loop continuous components, if line accidentally grounded, alarm will be triggered. Question Protection and Detection Systems 35 Answer 37
In a fire detection system with single loop continuous components with no fault protection if line accidentally grounded The fire alarm triggered, engine fire extinguisher striker automatically activated, there will be no effect on system, power supply cut off automatically. Question Protection and Detection Systems 35 Answer 38
When a continuous loop wire type fire detection system tested The wiring the warning are tested, wire totally heated, only warning function tested, a part of wire totally heated. Question Protection and Detection Systems 35 Answer 39
Regarding fire detection ion detectors are used to detect Smoke, overtemperature fire, fire, overtemperature. Question Protection and Detection Systems 35 Answer 40
Smoke detector systems are installed in the Upper cargo compartments (class e), wheel wells, engine nacelles, fuel tanks.
Exclusive rights reserved. Reproduction prohibited under penalty of prosecution.
1359 Free Training Exam Other source study: Canada drone examen 35