Engine Flashcards
GENERAL DESCRIPTION
The General Electric CF34-8E5 is a high-bypass and dual rotor turbofan, fully integrated with a nacelle and thrust reverse.
1 stage fan with 4 stage LP turbine (1/4)
10 stage axial flow compressor with variable geometry 2 stage HP turbine (10/2)
The engine is controlled via a dual channel FADEC system providing flexible engine operation and reduced workload.
max thrust is 14,200lbs
START/STOP SELECTOR KNOB
STOP:
STOP: commands the FADEC to shut down the engine,
provided the associated thrust lever is in the IDLE
position.
N1 WING ANTI-ICE CYAN LINE
(a) Displayed only in icing conditions during final approach (radio altimeter below 1200 ft) with landing gear down or flaps extended.
(b) Indicates the minimum thrust level (N1 value) to meet bleed requirements.
FUEL/OIL HEAT EXCHANGER
The fuel-cooled oil cooler (FCOC) maintains the oil temperature within an acceptable
range and heats the engine fuel to prevent freezing.
Each engine has an independent lubrication system.
./.
STARTING SYSTEM
(1) The engine starting system consists of:
(a) Air Turbine Starter (ATS).
(b) Starter control valve (SCV).
(2) The pneumatic system provides bleed air to the ATS to rotate the rotor speed and start the engine.
(3) The FADEC opens the Starter Control Valve (SCV), providing bleed air from the APU, a ground source, or the opposite engine. The Air Turbine Starter (ATS) is a turbine that accelerates the engine to a self-sustaining
rpm level.
(4) The FADEC closes the SCV when the starter cutout speed is reached.
,
Ignition System
(1) The ignition system provides an electrical spark for fuel combustion during ground/in-flight start attempts and for automatic re-light.
(2) The FADEC energizes one igniter for on-ground engine starts and both igniters for in-flight engine starts.
(3) When the ignition selector knob is placed on the OVRD position, both igniters on each engine are energized. Igniters 1B and 2B are connected to
SPDA 2. In case of SPDA 2 failure, setting the selector knob to OVRD energizes at least the igniter A.
.
GROUND START
A. The FADEC initiates ignition at approximately 7% N2 and the fuel flow (metering valve opens) at approximately 20% N2. FADEC will automatically switch to the other ignitor if no light off is detected within 15 s after initiation of fuel flow. The start should be aborted if no light off is detected within 30 s after initiation of fuel flow.
B. After a light off occurs, the FADEC commands the starter to cutout at approximately 50% N2, and commands the FMU fuel metering valve to accelerate
the engine to ground idle speed.
7% N2 ignition
20% N2 fuel flow
30 seconds light off
50% N2 starter cut out
IN FLIGHT START
A. Engine cross-bleed air, APU bleed air, or windmilling can be used for in flight engine starts.
B. An in flight cross-bleed start is identical to an on ground start, but the FADEC automatically controls fuel flow to initiate (Metering valve opens) if N2 has not reached 20% after 15 s.
C. For windmill starting, the SCV configures the pneumatic system. The engine start is controlled by the START/STOP selector knob and the FADEC commands ignition at 7% N2 and fuel flow at a minimum of 7.2% N2, or after 15 s, whichever
occurs first.
D. The FADEC has no protection for hot starts, hung starts or failure to light off for in flight engine starts.
E. If no light off is detected within 30 s after fuel flow is started, the start should be manually aborted
7% N2 ignition
20% N2 fuel flow
30 seconds abort if no light off
no IN FLIGHT start protection for
hot start (815C)
hung start
no light off
The thrust reverser is not designed to operate in flight. Uncommanded thrust reverser deployment limits engine thrust to idle.
.
FADEC Electrical Power
Above approximately __N2 the FADEC is powered by the Permanent Magnet Alternator (PMA). Below this value or in case the PMA becomes inoperative; the
airplane’s electrical system provides the backup power
50%
ATTCS Activation Logic
(1) The ATTCS automatically commands RSV whenever it is engaged, thrust levers are at TOGA position, and one of following conditions occurs:
(2) The RSV mode is manually activated by moving the thrust levers to MAX position whenever the ATTCS is engaged.
(3) Whenever the ATTCS is activated, the green ATTCS indication on the EICAS disappears and the cyan thrust mode will be displayed with an additional “RSV” indication.
(a) Difference between both engine N1 values is greater than 15%;
(b) One engine failure during takeoff;
(c) One engine failure during go-around;
(d) Windshear detection.
FLEXIBLE TAKEOFF
A. Flexible takeoff is a reduced takeoff thrust based on assumed temperature.
B. All takeoff modes are eligible for a flexible takeoff.
C. The assumed temperature ______than the TO TEMP and is set on the MCDU TAKEOFF DATA SET MENU page.
D. The indication FLEX TO-1, FLEX TO-2 or FLEX TO-3 will be displayed on the EICAS for the respective flexible takeoff thrust.
E. The minimum flex takeoff thrust is limited to ___ maximum rated takeoff thrust or ___________.
F. Flexible takeoff is possible with ATTCS ON or OFF. When flexible takeoff mode is used, moving the thrust levers to MAX position resets the assumed temperature and sets the maximum thrust available (refer to the Thrust Ratings Table)
must be higher
75%
CLB-2 + 0.5% N1, whichever is higher
FADEC Engine Protection
The FADEC provides engine start protection on the ground as follows:
(1) Hung start.
(2) Hot start.
(3) No light-off
