Powerplant Flashcards
The Challenger 350 is equipped with what two engines?
HTF 7350 or AS 907-2-1A
The engines on the aircraft are rated to what thrust?
Flat rated to 7372 take-off thrust pounds at ISA + 15C (86F) at sea level
What is the bypass ratio of the engine?
4.2 to 1
The core (N2) of the engine consists of …
Four stage axial compressor with two stages variable geometry.
Single-centrifugal compressor
Throughflow annular combustor
16 fuel nozzles
Two igniters
Two-stage high pressure turbine
Automatic power reserve extends flat rated thrust to …
ISA + 20C (95F)
The N1 sections consists of …
A fan driven by three low-pressure turbines
The N1 fan is made of …
22 titanium-inserted blades
The variable geometry system changes the position of …
The inlet guide vanes and stator vane for the inlet and first stage of compression
The VG system optimizes angle of attack of airflow at the compressor blades for what protection?
Compressor stall and surge protection
What moves the actuators of the VG system?
High pressure fuel hydraulically moves the actuators/mechanical linkage
What drives the engine accessory gearbox?
The N2 section
What components are mounted on the engine accessory gearbox? (7)
- Engine lubrication pump
- Hydraulic pump (EDP1 and EDP2)
- Engine fuel pump and fuel metering unit (FMU)
- Air turbine starter
- Integral oil reservoir
- Generator
- Permanent magnet alternator (PMA)
What does moving the L/R Engine switches to RUN do?
Turns on fuel DC boost pump and operates the ECU
What measures the position of the thrust levers?
Rotary variable differential transformers (RVDT’s) and microswitches within the thrust quadrant
The RVDT’s and microswitches provide information to the … (3)
- FADEC
- Flight Control Computers (FCC)
- Data concentrator units (DCU’s)
The FADEC controls what critical functions? (8)
- Engine thrust within required limits
- Bleed valve position
- Compressor guide vane position
- Nacelle anti-ice bleed flow
- N1 and N1 limits
- ITT
- Thrust Reverser operation
- Overspeed circuits
What does the FADEC use to control the engines/components critical functions? (3)
- Fuel control
- Compressor airflow management
- Engine starting/ignition
Each engine has how many FADEC computers?
Two, single-channel FADEC computers
What does each FADEC computer do for each engine?
One FADEC channel operates as the in-control channel and processes information for engine control output.
The other FADEC channel operates in standby
What does the FADEC standby channel do?
Processes all input information but does not provide output unless an overspeed condition exists
What occurs during an engine overspeed?
Both the in-control channel and the standby channel command the shutoff valve in the fuel metering unit to close thereby returning the engine to an onspeed condition
With regards to the FADEC, what occurs on each successive engine start?
Software directs the in-control and standby channels to alternate
APR is armed for takeoff when …
Thrust levers reach the TO detent
On an approach, APR is armed for a go-around when …
Gear is down or the flaps are greater than 20
On takeoff, should an engine fail and APR thrust occurs on the operative engine, APR thrust will continue until …
The throttle is retarded from the TO detent up to a maximum of 10 minutes
When APR is activated or selected, what icon appears to the right of N1?
A cyan APR icon
What is the primary source of power for the ECU?
The Permanent Magnet Alternator (PMA)
The PMA provides the electric power required by the ECU and engine at and above …
45% N2
When the thrust lever is placed in the idle position, the FADEC programs …
Maximum N2 idle rpm
There are three different N2 idle settings. What are they?
- Flight idle: Thrust lever set to idle while airborne
- Ground idle: Thrust lever set to idle with WOW. N2 is
minimum thrust setting and varies with altitude/temp - Reverse idle
On takeoff, when are the thrust calculations from the FADEC locked in?
At 65 knots
On takeoff, when are the thrust calculations from the FADEC unlocked?
Aircraft altitude exceeds 400’ AGL or the thrust lever is retarded below the TO detent
When does the FADEC automatically calculate normal-rated takeoff thrust?
When electrical power is applied to the aircraft on the ground. Essential Bus power.
During an engine failure, what difference must occur between engine N2 speeds to automatically activate the N1 speed (APR) of the operable engine?
15% N2
What must exist for the engines to be synchronized?
Thrust levers must be in the CRZ or CLB position and the sync switch set to N1 or N2
During engine sync operation, what engine is the master?
The engine with the higher N1 or N2 compensation or the left engine when the N1 or N2 compensation of the two engines is the same.
If the measured N1 or N2 of the slave engine is not within __?__ of the master engine set point, the FADEC indicates that sync is commanded but not achieved?
5%
What conditions must exist for MACH HOLD to be active?
- N1 and N2 must be synchronized
- aircraft must be trimmed for steady, level flight
- autopilot engaged in either altitude hold or altitude select
(altitude captured)
MACH HOLD authority only allows N1 to be adjusted within …
+1 or -2% N1
How is fuel delivered to the engines?
By the main fuel ejectors or standby boost pumps
Engine fuel system also performs four other functions.
What are they?
- Moves VG inlet guide and compressor stator vanes
- Cools engine oil
- Actuates and lubricates fuel system components
- Provides motive flow for scavenge and main ejector pumps
Moving the L/R ENGINE RUN switches to OFF shuts off fuel where?
Fuel metering unit (FMU)
Depressing the L/R ENGINE FIRE switches shuts off fuel where?
At the engine fuel shutoff valves in the manifold and at the FMU
Engine oil capacity is …
7.8 quarts with one quart unusable
What is the ideal time to check engine oil levels?
15 minutes but no more that 1 hour after engine shutdown
What is required to open the start valve and engage the air turbine starter?
DC electrical power and air from the bleed-air manifold
For engine starting, the bleed-air manifold can be pressurized by … (3)
- APU bleed air
- Ground Air cart (Huffer cart)
- Opposite engine bleed air (cross-bleed)
During the start sequence, the starter control valve closes at …
46% N2
The ATS disengages when N2 reaches …
50% N2
During an engine start, the FADEC will automatically abort for what?
Hot start or a hung start. Not provided though during an airstart
When will the FADEC automatically energize both ignition channels?
An aerodynamic stall or if it detects a flameout
When the manual IGNITION is pressed to ON, what channels are activated …
Both A and B
Manual ignition is recommended when?
- Turbulence (moderate or heavy)
- Thunderstorms (in the vicinity of)
- Rain (moderate or heavy)
- Contaminated runways
