Engines Flashcards

Question

How many outlet guide vanes

Answer 1

51 Lpg turbine outlet vanes

Answer 2

Module 31 – Fan Assembly Figure B3 This module compresses the air entering the engine inlet cowl and feeds a portion of it to the engine core, while the remaining (bypass) air provides 85% of the engine’s thrust via the bypass duct. The various components of this module are: 24 solid wide chord blades with dovetail root location 24 annulus fillers providing smooth airflow into core engine Fan Case Module M34 Fan Blade (24) Nose Cone (Spiner) and Fairing FAN DISC AND BLADES BASIC ENGINE Fan disc Fan blade retaining ring which also retains the annulus fillers Fan disc bolted to fan shaft (see Module 32) by means of a curvic coupling Retaining ring for the fan blades which also locates the (nonmodular) spinner Fan trim balance weights are fitted behind the spinner fairing. Fan blade numbers 1, 2, and 3 are etched onto the front face of the fan disc. Blades are numbered in a counterclockwise direction, as viewed from the front.

Answer 3

Yes on LP turbine

Answer 4

Module 61 Accessory Gearbox Figure B11 The accessory gearbox (AGB) transmits the driving force from the engine to the accessories mounted on the AGB. The AGB also transmits power from the air starter to the engine during start/crank procedures. In addition, the AGB houses the integral oil tank, and provides a means of hand turning the engine HP system for maintenance operations. Two standards of AGB are approved for the BR710 engine. The baseline AGB has a cast magnesium housing. An aluminium accessory gearbox is introduced, starting at A/C 9251. The accessory drives are the same on both AGBs. The AGB is bolted at the 6 o’clock position of the Fuel Metering Unit Variable Frequency Generator Fixed Mount Lugs No. 2 / 3 Dedicated Generator HP Shaft Drive Input Oil Pump Unit Fuel Pump Unit Air Turbine Starter Drains Mast (Ref) Hydraulic Pump TOP VIEW Fig. B11: Module 61 Accessory Gearbox ATA 71 Page B-12 BASIC ENGINE intermediate module via two brackets, and is driven by the radial drive shaft. The AGB drives the following units: Variable frequency generators (2 ea.) Air turbine starter Fuel pump and fuel metering unit Oil pump unit Hydraulic pump Dedicated generator Oil breather (internal) Access for turning the N2 (or HP) spool is through a plate on the rear face of the oil breather outlet. An AGB magnetic chip detector is located at the center of the AGB rear face.

Answer 5

Structural Bypass Duct Figure B13 The bypass duct is a structural engine component that provides a streamlined path for the fan bypass airflow and supports the thrust reverser unit. It also provides mounting features for many components related to the engine systems. The bypass duct is a single piece composite structure that bolts directly onto the rear flange of the intermediate module outer casing. It is bolted to the rear flange of the bypass duct is the rear support ring. The rear support ring is the attachment point for the core engine support struts on the inside. It also serves as the load-bearer for the thrust reverser unit, the core engine rear end and the rear engine mounts. Openings (with cover panels) in the bypass duct allow access to several core mounted system components. The system components are the bleed valve solenoid unit, VSV actuator, fuel spray nozzles, igniters, and ITT thermocouples. There are two variable frequency generator oil coolers (surface air cooled oil coolers). They are mounted on the inside surface of the structural bypass duct towards the rear. The bypass duct is protected from overheating due to malfunctions/ fires of externally mounted components by a special blanket wrapped around the bypass duct.

Answer 6

10 access panels

Answer 7

Engine Borescope Access Figure B16 Provision is made at various positions on the core engine to enable borescope inspection equipment to be used to visually examine a representative number of internal features. The LP system is rotated by turning the LP compressor blades by hand. The HP system is rotated by removing the accessory gearbox (AGB) breather cover and inserting a splined turning tool into the breather drive shaft. The turning tool flange is bolted to the breather and a standard ratchet drive fitting is used to rotate the tool and HP system. Engine stations are as illustrated in figure B16. A brief synopsis of the access to the various ports is as below: B & C: Two ports per stage, at 3 o’clock and 9 o’clock positions; access is via individual small cover plates in the bypass duct. D & E: Two ports per stage, at 3 o’clock and 9 o’clock; access is via the forward and middle bypass duct access panels. F: Accessed through the two igniter plug holes, via the forward and middle bypass duct access panels. G & H: One port per stage, at the 7 o’clock position.

Answer 8

COOLING AND SEALING AIR Figures B17 and B18 The engine is cooled internally with air that is tapped from different stages of the HP compressor. Parts of the engine that are at different pressures are isolated from each other by labyrinth seals. Air is taken from the fan bypass and from the HP compressor stages 2, 4, 6 and 10 for engine internal cooling and sealing purposes, including sealing of the accessory gearbox (AGB)

Answer 9

Fan Air Fan air flows through the turbine outlet guide vanes (OGVs), first to cool the OGVs and then the rear face of the LP turbine stage 2 disc and thereafter, the air baffle and the stirrup assembly of the emergency fuel shutoff system. The fan air next flows into the engine exhaust gas stream between the lp turbine stage 2 blade roots and the turbine outlet guide vanes

Answer 10

The FBC and AGB seals are fed by either HP2 air (at high engine power settings) or by HP4 air (at lower power settings). The changeover between HP2 and HP4 air is achieved through a buffer air valve which operates in conjunction with the variable stator vane (VSV) actuator mechanism.

Answer 11

HP6 Air Figure B17 An inward flow of HP stage 6 bleed air provides intershaft sealing of the FBC, cools the HP compressor discs and inside of the HP compressor drum, cools HP turbine discs and pressurizes the intershaft seal of the RBC. The air also cools the LP turbine discs, and flows into the engine exhaust gas stream between the LP turbine blade roots. The RBC HP6 air exhaust is monitored to detect turbine overheat by means of a detector. This subject is discussed in greater detail in subsequent paragraphs.

Answer 12

HP10 Air Figure B18 HP stage 10 air is bled through exits in the inner wall of the annulus between the stage 10 rotor blades and the outlet guide vanes (OGV). This air is routed around the HP compressor shaft and cools the front face of the HP turbine stage 1 disc. Another source of HP10 air bleeds off after the compressor outlet diffuser and flows around the combustion liner. Some of this air then cools the nozzle guide vanes and joins the exhaust gas flow. The remainder flows through preswirl nozzles that control the level of the cooling airflow. The preswirl nozzles direct the air at the optimum angle to enter the HP1 turbine blade roots. The HP10 air that enters the turbine blade roots goes in two directions, some of it flowing through the blades. After passing through the HP1 blades the air passes through the blade airfoil surface to provide film cooling. The remainder flows back out through the HP turbine stage 1 blade roots, between the HP turbine stage 1 and stage 2 discs. This cools the rear face of the stage 1 disc and the front face of the stage 2 disc. The air also cools the HP2 turbine blades, via holes on the blade root. Gas leakage at the shroudless blade tips is controlled by minimizing the tip clearances.

Answer 13

ENGINE BLEED AIR OUTPUTS (OR OFFTAKES) Figure B17 Each engine provides pressurized air for the following related groups: • Cockpit and cabin pressurization and air conditioning Wing and engine air intake cowl thermal antiicing (CAI) Crossflow air for opposite engine starting The ducting which is provided on the engine for routing this air can be supplied from the: Opposite engine HP compressor on the ground or in flight, via its- 8th-stage bleed air at lower power settings- 5th-stage bleed air at higher power settings • Auxiliary power unit (APU) which may be used on the ground or in flight, depending on circumstances • Pneumatic cart which is available only on the ground Details of related engine bleed air controls, operation and displays are in the pneumatics chapter (ATA 36) of this training guide.

Answer 14

Buffer Air – HP Stages 2 or 4 Air underpressure which helps in isolating or keeping apart from one another, those areas of the engine which are at different pressures, is called buffer air. Buffer air is supplied to both the front bearing chamber (FBC) and AGB seals. The FBC and AGB seals are fed by either HP2 air (at high engine power settings) or by HP4 air (at lower power settings). The changeover between HP2 and HP4 air is achieved through a buffer air valve which operates in conjunction with the variable stator vane (VSV) actuator mechanism. The RBC HP4 air exhaust is monitored for oil fire by means of a detector. More details on this subject are in subsequent paragraphs.

Answer 15

Buffer Air Valve Figures B19 and B20 The buffer air valve supplies HP4 air to the FBC seals at low power settings, when HP2 air is of insufficient pressure. In addition, HP4 air is supplied to the AGB air-blown seals at low engine speeds. The valve changes over the airflow between HP stages 2 and 4 by a rotary action. Air leaves the valve via a pipe connection on the side of the body. The valve is located on the left side of the HP compressor casing beneath a compressor fairing panel. It is mounted on a boss of the HP compressor casing by means of a flange with three bolt holes. Air enters the center of a hollow control element that has four rectangular slots. Rotation of the control element aligns the slots with corresponding slots in a close-fitting sleeve. Rotation of the control element is achieved via a lever connected to the variable stator vane (VSV) mechanism. The valve components and the lever mechanism have been designed to ensure that the buffer air valve will be open when the VSV actuator is fully extended and closed at a predetermined travel of the actuator (equivalent to 80% N2 approximately). No adjustment/rigging is required when replacing a buffer air valve.

Answer 16

Ice accumulation on the front of the engine nacelle can adversely affect engine performance in terms of power and economy and increase the risk of structural and impact damage. There are two methods of protecting the power plant against ice accumulation: 1. An ice protection feature which is passive by design 2. Active systems which use heat for ice protection

Answer 17

None, any leak is a problem

Answer 18

Rear Wet and Dry Drains Outlet Figure B28 This outlet groups a number of drains to a common point to allow easy troubleshooting for leaks. The outlet is mounted on a bracket attached at its front end to the rear support ring, and at its rear end, to the exhaust unit front bulkhead. The drain exit is at the bottom of the engine at the rear edge of the lower cowl door. There are three drains at the rear, consisting of plain tubes directed downwards and overboard, the tube ends protruding slightly below the cowl door surface. The three drains that exit at the bottom of the lower cowl door are a combination of dry and wet drains as follows: • Dry drain – variable stator vane actuator • Wet drain – drain tanks overflow • Combined structural bypass duct and interservices fairing Any leakage from these can be traced back to source by opening the lower cowl door.

Answer 19

INTRODUCTION The compressor airflow control system consists of variable angle stator vanes and the bleed valves, also called handling bleed valves. The variable inlet guide vanes and the first three stator vane stages of the HP compressor are collectively called the variable stator vanes (VSVs). They are coupled together and their position is controlled by a single fuel pressuredriven actuator in response to EEC commands. The VSVs control the angle at which the air enters the first four stages of the HP compressor and thereby ensure a smooth airflow at lower engine speeds. The compressor airflow control system also consists of four pneumatically operated bleed valves (also known as handling bleed valves). The handling bleed valves offload air from the 5th and 8th stages of the HP compressor into the bypass duct. Actuation of the bleed valves is provided by the bleed valve solenoid unit which is controlled by the EEC.

Answer 20

They are coupled together and their position is controlled by a single fuel pressuredriven actuator in response to EEC commands.

Answer 21

The compressor airflow control system consists of the following components and schedules: • Variable stator vanes (VSVs) and unison rings • VSV actuator • Electrohydraulic servovalve (EHSV) • VSV schedule • HP compressor handling bleed system • Bleed valve solenoid unit • Handling bleed valves • Handling bleed valve schedule

Answer 22

When the ram extends, the vanes will move to the closed (low speed) position. When the ram retracts, the vanes will move to the open position. The position of the ram is continuously transmitted to the EEC by two LVDTs, which are a part of the piston ram.

Answer 23

Inhibited below 56 percent n2

Answer 24

3 Magnetic Chip Detector Assemblies Figure D12 Magnetic chip detectors (MCDs) detect any ferrous material in the oil system. There are three MCDs in the oil system. They are positioned one each in the scavenge lines of the front bearing chamber (FBC), the rear bearing chamber (RBC) and the accessory gearbox (AGB). Both bearing chamber MCDs are OIL SYSTEM fitted in the oil pump unit, and the gearbox MCD is fitted at the 6 o’clock position of the AGB rear face. The MCDs are of the screw-in type and are wirelocked in position. Each MCD housing contains a coarse strainer. The MCD magnets attract a portion of the ferrous (or ferromagnetic) particles which are contained in the scavenge line oil.

Answer 25

Dry crank first

Answer 26

Yes, indicates any leakage

Answer 27

5-30 mins after shutdown, never cold

Answer 28

3 qts for more than 10mins

Answer 29

Low oil press when engine is running, press below red line inhibited when N2 is below 56 percent

Answer 30

Engine Electronic Controller Figure E3 The engine electronic controller (EEC) is the controlling unit of the FADEC system. The unit is fitted onto the bypass duct at the 12 o’clock position by four antivibration mounts, encased in a yellow metal box for fire protection, and protection against high intensity radiated fields (HIRFs). A connection is provided for the data entry plug. The EEC is an electronic control unit containing two channels, A and B. Each channel consists of a central processor unit (CPU), power supply unit (PSU) and an independent overspeed protection (IOP) unit mounted on application-specific integrated circuit (ASIC) boards. Internal hardware features provide fire protection between the two channels. Each EEC channel has three external electrical connections mounted on connector modules. The front three are part of channel B. The rear three are part of channel A. The EEC also houses vibrating cylinder pressure sensors for measurement of P50 and P20, and strain gauge sensors for P30 and P0 (ambient pressure). Internal temperature sensors are also included to provide cold junction temperature signals for ITT, engine overheat and T30 measurement/validation.

Answer 31

28vdc batt bus

Answer 32

Tells engine where its fitted

Answer 33

Channel A and B 3 plugs per channel

Answer 34

ARINC 429 from eec

Answer 35

4 EEC Watchdog Timer Both lanes of the EEC have a watchdog timer. If the watchdog timer senses a CPU malfunction within a time scale then it will impose a CPU reset. In this situation control passes to the other channel temporarily. A counter is incremented and decremented periodically as control passes temporarily between channels by the CPU. If the counter reaches four CPU resets the watchdog will impose a freeze and control will pass to the other channel until the fault is rectified and cleared at which point alternating channel control will resume.

Answer 36

Yes, 3 phase,supplies cpu and eec, fadec

Answer 37

Press menu button on MFD for 3 secs

Answer 38

The main components related to the operation of the engine fuel system are the throttle levers and the engine fuel control switches in the flight deck. The full authority digital engine control (FADEC) system provides control of the fuel system using a high pressure (HP) fuel pump and a fuel metering unit (FMU).

Answer 39

The delivery from the HP fuel pump (which is a gear-type pump) will always be in excess (approximately 120%) of engine demand. The excess over demand is returned to the HP pump inlet (as discussed later), and is referred to as engine “fuel spill”. The excess return fuel can be diverted through the fuel return to tank (FRTT) valve operation to circulate heated fuel back into the aircraft wing tanks. Control of the fuel spill allows acceptable levels of overfueling/ acceleration or underfueling/deceleration as required. In addition to fuel metering requirements, the system supplies HP servo fuel to the variable stator vane (VSV) actuator described in section C, under the heading compressor airflow control.

Answer 40

Synoptic goes amber

Answer 41

Yes, they are duplex, 20 off nozzles

Answer 42

The drain tank collects fuel from the fuel manifold after engine shutdown and delivers it back to the LP pump inlet during the next engine run. The tank is bolted to the bypass duct rear flange and to the exhaust case support flange via two brackets, and is located at the 6 o’clock position.

Answer 43

Drain tank ejector

Answer 44

Throttle position information is transmitted by four rotary variable differential transformers (RVDTs) connected to each throttle lever. Two RVDTs are connected to the flight control unit (FCU) and two RVDTs are connected to the electronic engine controller (EEC). An engine run switch and a “finger lift” lever (thrust reverser operation) for each engine are also located on the TQA.

Answer 45

Throttle position information is transmitted by four rotary variable differential transformers (RVDTs) connected to each throttle lever. Two RVDTs are connected to the flight control unit (FCU) and two RVDTs are connected to the electronic engine controller (EEC). An engine run switch and a “finger lift” lever (thrust reverser operation) for each engine are also located on the TQA. The EEC provides an excitation current to the throttle resolvers. The resolvers generate a voltage relative to throttle position which the EEC then reads as a power demand signal and sets engine power accordingly. The resolvers are hardwired to the EEC. There is no mechanical link between the flight deck levers and the engines (fly-by-wire system). The TQA has autothrottle servo drive motors. These power drives, one for each throttle lever, move the levers during the autothrottle mode as commanded by the IAC. The drive motors are connected to the throttle levers such that a motor jam or failure can be overridden by the pilot.

Answer 46

Retard throttles then select N1

Answer 47

1. Sync command for N1 or N2 speed synchronization between engines 2. TRA trim command for synchronization for EPR command between engines 3. TRA position error trim command to account for throttle positioning inaccuracies when autothrottle is engaged (commanded vs. actual)

Answer 48

860 degrees c

Answer 49

4 ,P50, at aft engine, helps the value for EPR, ref TAT for p0 and p20 for input air to EPR

Answer 50

Yes dedicated generator on engine

Answer 51

3, 4th is vibration also speed 4th sensor feeds EVMU, vibration monitoring

Answer 52

T30 Thermocouple The T30 thermocouple is a probe, mounted to the engine via a three-hole flange, and a takeoff lead terminating in three ‘flying leads’ with terminal tags: a positive thermocouple connection, a negative thermocouple connection, and a connection to ground. The ground probe contains a mineral insulated type K (Alumel/chromel) thermocouple element. The flange of the probe incorporates a groove to accommodate a metal ‘C’ seal to seal against engine pressure. The thermocouples operate on the same principle as the ITT thermocouples. Each probe is wired to a separate EEC channel. Access to the thermocouple units is gained through the bypass case lower left and lower right access panels respectively. Care must be taken to ensure that the lower body of the probe is fully withdrawn before attempting to remove the probe.

Answer 53

P0 Pressure Signal Figure H9 The purpose of the P0 pressure signal is to provide the EEC with an ambient pressure value for system scheduling and signal validation. The P0 signal pickup is part of the EEC assembly and consists of a protective mesh screen over the pressure inlet port on the EEC pressure transducer module. P0 is actually undercowl pressure that is relative to ambient pressure. The P0 pressure is validated by a range-check. The range-check is 1.0 to 18.0 psia. There are no separately removable parts on the P0 pickup.

Answer 54

P30 Pressure Signal Figure H10 The P30 pressure signal is used to provide indication of surge and recovery by the engine, as controlled by the EEC, and for fuel scheduling. The P30 pressure pickup is bolted to the outer combustion case and is a flanged hole in the casing to which an elbow and pipe are attached. The pressure (pipe) is then routed to two (channel A and B) strain gauge transducers in the EEC. The P30 line incorporates a moisture trap at the exit from the interservices panel.

Answer 55

The BR710 engine is started by means of a pneumatic starter and a dual high energy electrical ignition system. Starting and motoring cycles are initiated from controls in the flight deck and routed through the FADEC, which uses the electronic engine control (EEC) as its main component to provide the following services as needed: • Automatic ground and air starts • Manual ground and air starts • Wet and dry motoring • Continuous ignition The above services and other associated features of the starting and ignition system are described in detail towards the end of this section under “Starting and Motoring Procedures”

Answer 56

15 percent 42 percent N2 starter disconnects

Answer 57

EEC 1 OR 2

Engines Flashcards

(90 cards)