Engine & Power Systems Flashcards
MAX Thrust/MAX Rated Thrust
20,700 lbs / 21,890 lbs
FAN VIB Max
1.6 ips
CORE VIB Max
2.2 ips
FADEC
Full Authority Digital Engine Control
Controls engine parameters based on Mission Computers (MC), Flight Control Computers (FCC), and Throttle angle by modulating fuel flow and engine geometry
2 FADEC’s:
- 1 per engine
- Each FADEC has two channels
ENGINE STATUS
NORM - Engine performance is normal
PERF 90 - 10% or less thrust loss and or slower engine transients. Afterburner is not inhibited
AB FAIL - No Afterburner capability
THRUST - Engine thrust is limited to between 40% and 90% and significantly slower transients
IDLE - Engine is limited to idle power only
SHUTDOWN - Engine automatically shut down
Oil Systems
1 Engine oil system
1 AMAD oil system
Both systems contain a pump, scavenge filters, chip detectors, routed through the AMAD and hyd oil fuel heat exchanger
OIL PRESSURE
Pressure transducer senses exact oil pressure
Pressure switch senses above 35psi
If EFD shows 0 psi but no OIL PR Caution, the transducer has failed
OIL TEMPERATURE
If Engine Oil > 149C or AMAD Oil > 88C, OIL HOT Caution will appear.
Must check engine page to identify problem source.
Best cooling RPM is 72% N2
FADEC Power Sources
Normal Power is provided by Engine Driven Alternator with 28 VDC Essential bus serving as a backup.
10 seconds after both generators are online the backup power is tested. If insufficient, this will provide a FADEC DEGD and takeoff is prohibited.
FADEC will operate opposite channel from the previous flight.
FADEC Alternator Fail (CH A / CH B)
CH A powered by - ESS DC Bus, GEN through transformer rectifier, PMG, Battery
CH B powered by - Engine DC Bus, opposite Engine DC Bus
Engine Driven Alternator
Via a separate dedicated shaft, provides electrical power to:
- FADEC
- Ignition Systems
- Afterburner
Ignition System
FADEC controlled providing alternator power to ignition exciters.
- 10-45% rpm during start
- Flameout
- Throttle in AB until AB lit
- Trigger squeeze +5sec for Gun, any A/A weapon, or forward firing A/G weapon
VEN (Variable Exhaust Nozzle)
Controlled electrically by FADEC
Fuel used as hydraulics to position Nozzle
Provides maximum thrust efficiency during Idle (opens 77-83% to maximize airflow)
Less than MIL (Closed 0-45%) to maximize subsonic airflow
Afterburner (Full Open 50-100%) to maximize supersonic airflow
Engine Anti-Ice
Operational when Inlet Ice detector senses 0.025” of ice while airborne and inlet temp is -40C to 15C
System shuts off with WonW
Uses 7th stage bleed air
- Increases N2 by 2% and EGT by 5C
Executes Self Test 45sec after engines idle, stays on for 30sec
- will see L/R HEAT advisory on DDI
Fan Speed Lockup (SLU)
Hold engine RPM at MIL when throttles reduced at high speed until aircraft slowed to prevent inlet instability and reduce buzz.
Active >1.23IMN until below 1.18IMN
SETLIM (Supersonic Engine Thrust Limiting)
If flameout or stall occurs at mach or high Q, no AB is allowed for up to 12sec to prevent asymmetric thrust induced departure.
RATS (Reduced Authority Thrust System)
Reduces thrust to 70% of MIL after Trap
Armed when Gear and Hook down
Low and Mid Range AB is not available, only Full AB available and will disable RATS
Reduces wind over deck by 7kts to reduce airframe wire stress
On with WonW, INS indicated > 1.0 horizontal deceleration, rapid wheel deceleration
OFF with Throttle Idle, wheel speed
AGIP (Armament Gas Ingestion Protection)
Ignition on for 5sec after gun, any A/A trig squeeze, A/G rocket or missile on inboard pylons
ABLIM
Limits engines to half AB during cat shot (to prevent re-ingestion of exhaust)
- Defaults to off at start, Box in CHKLIST page with FLAPS in HALF/FULL
- Cancelled with catapult acceleration, 80KCAS, or WoffW
- Failed with FCC CH1, FCC CH2, FCC CH4, MC1 or FADEC failure
IBU (Ingestion Bleed Usage)
Lot 26+ during high bleed flow rates to prevent turbine overhead, MIL/MAX red 1.5% over Lot 25+
ATC (Auto Throttle Control)
Cruise (flaps AUTO) - Captures airspeed in box when engaged
Approach (flaps HALF/FULL) - Captures on-speed (8.1 AOA), to trim for on-speed, BIT/MI > Unit 14
Automatic change between modes or engagement with single engine is not possible
Disabled by pushing ATC Button on throttle or applying >12lbs on throttles
Engine Record
Records +/- 15sec anytime engine voice alert occurs
Engine Overspeed Cutout
FADEC will shutoff fuel flow if N1/N2 reaches 107%
Will open Solenoid when N1>50% or N2>75%
Hot Start Limits
NATOPS definition is 871C
FADEC will limit temp to below 815C on ground start only
Procedural Limit 750C
AMAD (Airframe Mounted Auxiliary Drive)
Mechanically driven by engine via the power transmission shaft.
- Motive flow boost pump (37hp) operational above 28% rpm
- Generator (12hp) operational above 60% rpm
- Hydraulic Pump (120/200hp) operational above 14% rpm
- Air Turbine Starter
APU (Auxiliary Power Unit)
Air source for ATS and alternate air source for ECS cooling (AUG PULL)
Receives fuel from Left Engine feed upstream of engine feed shutoff valve
Turns off 1min after 2nd GEN online
Operating Envelope is below 10,000ft and below 250KCAS
Maximum of 30sec between start and ready, requires a minimum of 2min between APU shutdown and another APU start
Air Turbine Starter
Provides AMAD and engine rotation for engine start or accessory usage while single engine
Powered by APU, opposite bleed air (crossbleed), or external air
Overspeed cutout primary power is GEN (GEN must be on), secondary power Frequency Sensing Relay (FSR) shuts off ATS @ 63% N2
Restart Envelopes
Spooldown - >150kts below 20,000ft or >250kts below 30,000ft, below 1.0IMN, assumes 50%RPM
Windmill - >350kts below 30,000ft, below 1.0IMN, 12% RPM minimum (500kts is HYD pump high mode)
Crossbleed - >150kts, 80% RPM
APU - >250kts,
Power Transmission Shaft Failure
Indicated by HYD A, HYD B, GEN and BOOST LO, possible also DC FAIL
MIL Thrust
13,900 lbs
