Engine Systems (work in progress) Flashcards
What are the 5 major sections of the CFM F108-CF-100 engines?
1) Fan
2) High Pressure Compressor
3) Combustion
4) Turbine
5) Accessory section
What are the main parts of the:
Fan Section
- Fan + 3-stage low pressure compressor
- 80% of T/O thrust
- Fixed stators
- PMC’s above 70% N1. Trims MEC
What are the main parts of the:
High Pressure Compressor
- 9 Stages
- First 3 have variable inlet guide vanes
What are the main parts of the:
Combustion
- Dual ignition, 20 fuel nozzles, annular ring
- Fuel metered by MEC
- Igniters at 4 o’ clock, 8 o’clock
What are the main parts of the:
Turbine
- High and Low pressure
- High: 72 blades, single stage powers high pressure compressor
- Low: 4 stages, powers fan + low stage compressor
What are the main parts of the:
Accessory section
- Mechanically driven by high press. compressor (N2)
- Located at engine 6 o’clock
- Engine fuel pump
- Main Engine Control (MEC)
- Hydraulic Pump
- Constant Speed Drive
- Generator
- Control Alternator
- Lubrication Unit
Controls and Indicators:
Function of the Throttle Quadrant?
Controls the engine RPM through the MEC with the PMCs off
Controls and Indicators:
Function of the Engine Ignition Control and Start Panel
- IGNITION provides constant spark through full throttle movement. Does NOT open the starter valve
- START opens the starter valve and provides spark between 1/2 way to START and IDLE
- Starter valve light on when valve opens with 5 degrees
Controls and Indicators:
Function of the Engine Oil Pressure Warning Lights
- On below 11 psi or if filter clogged
- Off above 13 psi
Controls and Indicators:
Function of the PMC panel?
- Connects PMC to respective MEC
- Switch powered by respective engine
Controls and Indicators:
Function of the Engine Fire/Overheat Detection and Extinguishing Controls?
- Compartment Hot lights
- Fire Lights
- Fire EXT Light
- Fire Switch
- Fuel
- Hydraulics
- Pneumatics
- Ignition
- Generator input
- Fire bottle armed
Controls and Indicators:
Function of the Electronic Engine Instrument Display (EEID)
N1
- Actual N1 white needle/text
- Demanded by N1 (cyan)
- 100% N1 = fan speed 5,175 RPM
- Continuous range 78% - 95.8%
- GREEN within 1% of target
- Caution 102.5% - 105%
- Max 105.1%
Controls and Indicators:
Function of the Electronic Engine Instrument Display (EEID)
EGT
- Continuous 610-870 C
- Caution 870-905
- Warning 905 and above
- Flight limit 930
Controls and Indicators:
Function of the Electronic Engine Instrument Display (EEID)
N2
- 100% N2 = 14,460 RPM
- Continuous 89%-95%
- Caution 105.1%-106%
- Max 106.1%
Controls and Indicators:
Function of the Electronic Engine Instrument Display (EEID)
Fuel Flow
- 0 - 15,000 PPH
- During start, 300-680 prior to ignition, 900 after ignition
- Idle, ~800 pph
Controls and Indicators:
Function of the Fire/Overheat Detection and Extinguisher Systems
Logic Relay relationship between pulling fire switches and arming bottles
Controls and Indicators:
Function of the Electronic Engine Instrument Display (EEID)
Oil
- Oil Gauge is 0-100 psi
- Continuous 11-92 psi
- Warning outside 11-92 psi
- Temp gauge -50 - 200
Continuous -10 - 160
Warning 175 and above - Engine start caution: -50C to -10C
Controls and Indicators:
Function of the Fuel Control Systems
Throttles
- Mechanically linked to MEC
- Sets N2
- Position sent to PMC to maintain N1
Controls and Indicators:
Function of the Fuel Control Systems
MEC
- Sets N2 by metering fuel based on throttle position, altitude, temperature
- Changes variable stators and variable bleed valves
- Controls turbine clearance system
- Inputs include:
- N1
- Fuel flow
- Fan inlet static pressure
- Compressor inlet temp
- Throttle position
- Torque motor current
- Compressor discharge pressure
- VSV/VBV feedback
Controls and Indicators:
Function of the Fuel Control Systems
PMC
- Trims MEC
- Inputs
- MEC
- Fan inlet static pressure
- Fan inlet temp
- Actual N1
Controls and Indicators:
Function of the Engine Ignition Control and Start System
- Open starter valve allows low pressure bleed air to the starter
- Can be manually opened
- Starter auto-cutout begins 43-45% and takes 3-9 seconds
What are the 5 major sections of the Auxiliary Power Unit (APU)?
- Centrifugal Compressor
- Turbine
- Combustion Chamber
- Load Compressor
- Variable inlet guide vanes
What are the 3 modes that you can run the Auxiliary Power Unit (APU)?
- Normal
- Gen only
- EWO
What happens if you takeoff with the APUs running?
Squat switches start the Auto-Shutdown if you takeoff with the APU’s on
APU controls:
Crew entry chute switch
Starts/Upgrades both APU’s to NORM
APU controls:
Where can you start the APUs from?
- APU control panel in the back
- Crew entry chute
- Pilot Start/Stop switches
APU controls:
What does the EWO switch do?
- Starts both APUs in EWO mode
- To downgrade, must be shutdown and restarted
APU controls:
APU Aft Control Panel
- RPM gauge normally 100%-103%
- RDY light at 100%
- GEN only available from here
- Surge Damper preload normally 1,600 psi
- Start accumulator should be 3,000 (+/- 350) psi
APU controls:
How much fuel does each mode use, and where does it draw its fuel from?
- GEN only:150 pph
- NORM: 250 pph
- EWO: 275 pph
- Fuel from #2 main tank
Engine Operating Environment:
Where are the engine danger areas for ground personnel?
25’ in front and to the side
5’ behind the inlet
Engine Operating Environment:
Cold Weather Ops
- If less than -50C oil temp, heat oil, starter valve, MEC
- Increasing oil pressure
- Idle for 2 minutes prior to 70% N1
- JP-8 below -23C specifics:
- minor torching may occur
- Check MEC set for JP-8
- Max Motoring 25-27%
- Monitor EGT
- Abort start if no lightoff after 60 seconds
Engine Operating Environment:
Hot Weather Ops
- Do as much of the preflight as possible before starting engines
- Expect slower acceleration because of less dense air
- APU ambient temp limits in -1
Engine Operating Environment:
Volcanic Ash Ops
- Stay away!
- Starter switches IGNITION, turn on bleed systems
- Airspeed probably unreliable
- Exit via shortest route, descend lowest thrust setting
- Avoid rapid throttle movements
- Record info required by -1 and report to maintenance
