TSA EMB145 Power Plant and APU Flashcards
Power Plant
AE3007 Rolls Royce Turbofan Engine.
High bypass ratio, two-spool axial flow turbofan.
Max T/O Thrust - 7426 lbs (XR 8810lbs)
Power Plant Design Features
Single stage fan.
14 stage axial-flow compressor w/ inlet guide vanes & 5 variable geometry stator stages.
2-stage high pressure turbine to drive the compressor.
3-stage low pressure turbine to drive the fan.
Dual redundant, FADEC.
Accessory Gearbox.
Pneumatic system for pressurization and engine starting.
Starting Sequence
Start/Stop Selector - Run 2 sec Start/Stop Selector - Start 3 sec max N2 rotation 14% Single ignitor 28% Fuel flow w/ in 5 sec ITT rise N1 rotation 56.4% N2 ignitor deselected
Start Complete
Check: N1 20% ITT 400 N2 60% FF 300 - 400 PPH SCV close @ 53% N2
Reasons to Abort Start
Fuel flow +800 PPH prior to light up.
No light up in 10 sec after Fuel Flow Indication.
ITT rises rapidly to start limit.
ITT approaches start limit.
N2 remains steady or decreases for +30 sec. Any unusual noise or vibration.
Engine instruments indicate abnormal conditions.
Visible burning on the exhaust pipe.
Oil pressure doesn’t reach 34 psi when engine reaches stabalized idle.
Pneumatic Starting
Sending compressed air through the air turbine starter(ATS). Sources: APU (primary) Ground Cart Crossbleed from other Engine Windmilling
Engine Bleed Valve Logic
Bleed Air Button OPEN:
Respective Ess. Bus energized.
No massive leakage.
Respective N2 +56%.
Respective Fire Extinguishing Handle not pulled.
Bleed is requested by one bleed consuming system.
When does 14th Stage Bleed Valve open?
14th stage pressure low( low thrust).
Anti-Ice is required.
Cross Bleed starting.
Crossbleed Starting
XBLEED_AUTO or OPEN
ENG BLEED (non operating)_CLOSE
ENG BLEED(operating)OPEN
N2 Operating ENG+80% N2
What Bleed Valve assists in Engine Start?
Compressor Acceleration Bleed Valve (CABV)
When does the Starter Control Valve (SCV) Shutoff?
@ 53% N2 begins to close, should be closed @ 56.4%.
EICAS msg +53% N2 plus 10 sec if not closed
How many Start attempts may you do?
Only Two then call Maintenance.
Dry Motor between each start attempt.
Abnormal Engine Start checklist every time.
Vapor Vent Valve operation?
Only open early during start.
Specifically closed when engine not running.
EBV Definition & Purpose
Engine Bleed Valve
Bleed air from 9th or 14th stage for Pressurization & AC.
9th stage during start to assist w/ accelerating to idle RPM.
Ignition System
Two ignitors per engine.
Wired to their associated FADEC.
(FADEC A to IGNITION A)
(FADEC B to IGNITION B)
When would you select ignition to the ON selection?
During Cold Start (OAT 5C or less & Cold Eng (shutdown for 90min) Ground Cart Start QRH Volcanic Ash Heavy Rain
When will you see ignition for a normal engine start?
Auto__14 - 56.4% N2
ON____10% N2
What is the purpose of Closed-Loop Fan Speed Control?
FADEC checks N1 request & actual N1, compares the two, then adjust fuel to make N1 = N1 request.
FADEC How many? Definition? Failure?
4 FADEC (2 per Eng.) Full Authority Digital Electronic Control If both FADEC's on one engine fail the engine will shutdown.
FADEC directs FPMU to provide fuel for:
Starting Operating Windmilling Shutdown CVG operation
What does the FADEC’s need to know before each flight?
Thrust Setting Temperature (w/ in 10C) Anti-Ice ON or OFF
When will the FADEC shutdown an Engine in an Overspeed or Underspeed Condition?
MIN__54% N2
MAX__100% N1 or 102.4% N2
CVG Functions & Definitions
Compressor Varible Geometry 6 stages, driven by hydraulic system. Commanded by FADEC. Operated by high pressure fuel. Two Basic Functions: Efficiency &Prevents Compressor Stall
What is the purpose & operation of the Starter Control Valve (SCV)?
Regulates air supplied to the Air Turbine Starter (ATS).
Electrically commanded, pneumatically operated & spring loaded to close position.
FPMU Definition & Operation
Fuel Pump & Metering Unit
Electrical-Mechanical, Fully-Integrated line replaceable unit.
High pressure pumps, meters fuel, filters fuel & operates CVG.
What is the purpose of the FPMU Low Pressure Centrifugal Pump?
Raises fuel pressure high enough to meet the requirements of the high pressure pump and ensures fuel is vapor free.
Describe High Pressure Compressor
14 stages
CVG stators are provided for 1-5 stages & for inlet guide vanes. Controlled by the FADEC.
HPT Purpose
2 Stage High Pressure
Converts gas flow coming from the combustion liner into usable mechanical energy to drive the compressor.
LPT Purpose
3 stages
Extracts energy from the gas path to drive the FAN.
LPT is connected to the FAN by means of a Shaft extending through the entire HP Spool & Compressor assembly.
LPT & Bypass air provides thrust.
If DC’s Fail, will your engine still run?
Yes, by using PMA’s. (Permanent Magnetic Alternator)
When does PMA provide sufficient power?
Min 50%N2 for FADEC
10%N2 for Ignitors
What four items does PMA power?
FADEC’s Thrust Levers Thrust Mode Buttons Ignitors (PMA is the only power source)
Lubrication System
Oil Tank
FCOC
ACOC
Gear Box
FCOC Definition & Function
Fuel Cooled Oil Cooler
Cools engine oil & warms fuel.
Fuel never bypasses.
Accessory Gear Box
Driven by HP Spool (N2) FPMU ATSGenerators (2 DC) Hydraulic Pumps Oil Pumps PMA
Where is N2 picked up?
Accessory Gear Box
What happens if the tower shaft brakes?
Engine Failure, because FPMU is connected to the Gear Box.
Where are the 5 oil sumps?
FAN FWD CENTER AFT AGB
Engine Fuel System Components
FPMU
FCOC
CVG
16 Fuel Nozzle’s
What happens if all three fuel pumps in each wing fail?
FPMU will provide suction to supply fuel to the engine.
What are the different idle speeds?
Ground
Flight
Flight in Icing Cond.
Ground Idle Logic
Avoid Flame Out.
Avoid Over Temp.
Bleed for ECS.
Gas Gen Speed to drive Accessories.
Flight Idle
Avoid Flame OutOver Temp.
Bleed for ECSFull thrust in 8 sec.
Flight Idle in Icing Conditions
High thrust setting for Bleeds.
Inhibited when gear down below 15,000 ft.
What is ATTCS?
Alternate Takeoff Thrust Control System
When would ATTCS trigger?
One TLA less than 38 deg.
Inop Engine.
ATTCS not armed w/ in 2 sec of each other.
ATTCS isn’t disarmed w/ both engines w/ in 2 sec.
What situation would command MAX T/O THRUST mode? (T/O-1)
Auto: A/C Power Up. ATTCS mode.Below 15,000 ft w/ gear down. Above 78deg TLA. Manually: T/O thrust button Must use T/O-1 mode for takeoff on a Contaminated runway, Windshear or if Performance requires it.
What situation would command ALT T/O-1 mode?
Normal Takeoff
Performance Allows ALT T/O-1
ATTCS Operational
When may you select CLB mode?
No Engine Inop.
Above 500ft Gear Up
Above 1700ft
Inhibited on the ground.
When may you select CRZ mode?
No Engine Inop.
Above 500ft Gear Up
oAbove 1700ft
Inhibited on the ground.
When may you select CON mode?
Above 300ft Gear Up
Above 1700ft
Inhibited on the ground.
Describe the APU
Single-stage centrifugal compressor, a reverse flow anular combustion chamber & a single-stage radial turbine.
Describe APU Starting Sequence
APU knob select ON
Blinking yellow RPM box
Yellow box steady
APU START selection till 55%
APU Bleed Valve Operation Logic
APU Bleed OpenEss. DC Bus #1 energizedEngine Bleeds ClosedNo massive leakage on APU line.
When is the APU capable of emitting bleed?
@ 95% for 7 sec.(3 min per SOP)
What does the APU bleed system consist of?
Flow Limiting VenturiBleed ValveAnti-Surge Valve
How is the APU supplied with power?
1 Central DC Bus &2 Essential DC Bus
Pack operation during Engine Start
APU Bleed:
Not enough power for engine start with packs on, FADEC automatically turns packs off until engine started.
APU Fire Extinguishing Button Logic
Closes APU fuel Shutoff valve. Discharges APU fire extinguisher bottle. APU shutdown: c11- simulates overspeed c14- stop request signal to FADEC
APU Shutdown Procedure
APU Stop Button\_\_Press APU EGT & RPM\_\_Monitor Below 5% RPM APU Master\_\_Off Observe APU FUEL SOV CLSD" on EICAS Fuel Pumps\_\_As Required"
Ground Safe Mode
APU Gen__On APU Bleed__Off IRS(if installed)__Off Emer. Lights__Off Batteries__Off
How much PPH does the APU burn?
95 - 160 LBS Per Hour depending on the load.
Who is the best pilot in the company?
Bob Lamar, of course…