NATOPS Chapter 2 Flashcards
Aircraft Engines
four AE 2100D3 turboprop engines
Takeoff Power (Maximum)
4,700 hp at temperatures up to 39.4 degrees C, at sea level with no bleed air
Maximum Continuous Power
4,700 hp at temperatures up to 28.3 degrees C, at sea level with both air conditioners on
Three major assemblies of the engine
1) Power section (two-rotor system with a free power turbine)
2) Propeller gearbox (plus propeller)
3) Joined by a torquemeter (shaft and interconnecting struts)
Propeller Gearbox function
Transmit power from the torquemeter to the propeller, reduce shaft RPM, and provide shaft power to the GMAD
GMAD what is it and what does it do?
Gear mounted accessory drive.
Located on the PGB, provides drive pads for the aircraft hydraulic pump, an oil cooled ac generator, the PGB oil supply and scavenge pump, propeller high pressure oil pump and overspeed governor, and the propeller pitch control unit.
Torquemeter function
Transmit engine output power to the PGB and to supply torque reference to the FADEC’s
Power section primary features
1) Fourteen-stage axial flow, variable speed compressor. The inlet guide vane and the first five stator stages are variable.
2) Two-stage air-cooled, variable speed gas generator turbine; two-stage free power turbine.
3) Two FADECs for redundant, fully integrated control of engine and propeller system
Power section accessory gearbox contains
1) Gearbox-driven FPMU
2) PMA
3) Oil pressure and scavenge pumps
4) Air turbine starter
What is a FADEC and what does it do?
Full Authority Digital Electronic Control
2-identical single channel FADECs (A and B). Control propeller and engine. Provide data, status info, and fault indications to the mission computer. During engine operation both are functional, however only one is in actual control.
What determines the controlling FADEC?
1) Each time an engine start is initiated with weight on wheels, the FADEC selection automatically alternates.
2) FADEC fault serious enough to render the controlling
Input parameters used by the FADECs for controlling the engine and propeller include:
1) Torquemeter (HP)
2) Gas generator speed (NG)
3) Power turbine speed (NP)
4) Measured gas temperature (MGT)
5) Compressor inlet air temperature and pressure
6) Fuel metering valve position
7) Compressor variable guide vane position
8) Prop blade angle
9) Prop magnetic pulse unit
10) Nacelle ambient air pressure
When engine speed reaches approximately ___ percent, the engine ___ supplies electrical power for the FADEC operation.
40%
PMA
Explain prop speed (NP)
Accomplished by varying propeller blade angle and/or engine fuel flow. The blade angle is controlled by the PCU in response to the FADEC. The FADEC controls engine fuel flow by providing signals to the FPMU
Forward Thrust is…
When the power levers are forward of FLT IDLE, FADEC schedules torque as a function of power lever angle. The prop speed is maintained at 100 percent through blade angle changes.
Ground Range is…
When the power levers are between FLT IDLE and reverse range, the FADEC schedules blade angle as a function of power lever angle. The propeller speed is maintained at 99 percent through fuel flow changes.
Reverse Thrust is…
When the power levers are in the reverse range, the FADEC schedules torque as a function of power lever angle. The prop speed is maintained at 101 percent through blade angle changes.
GND IDLE Blade Angle vs. Calibrated Airspeed
When the power levers are at GND IDLE, the FADEC programs the inboard and outboard propeller blade angles differently as a function of calibrated airspeed.
Outboard blade angle above 110 knots
Outboard props 1 degree blade angle
Outboard blade angle between 110 and 90 knots…
Outboard props increase from 1 degree to 8 degrees blade angle
Blade angle between 70 and 50 knots…
Outboard decrease from 8 degrees back to 1 degree. T
Inboard props are set to 1 degree.
Blade angle below 50 kts…
All props are at 1 degree
Inboard props blade angle at all calibrated airspeeds down to 70 knots…
-2 degrees
FADEC autofeather request parameters:
The FADEC will request MC permission to autofeather if the power lever is at ___ ____ or above and any of the following exist:
a. Loss of prop control (high power and NP below 73 percent)
b. At low power settings, low NG (less than 69 percent)
c. At high power settings, low engine HP (less than 74 percent of commanded HP) and decelerating NG (greather than 500 rpm per second)
MC autofeather permission…
The outboard props always have MC permission to autofeather without delay (low min control speeds).
Inboard props auto-fx permission is granted after a 2 second delay provided the a/c is below 15,500 feet and the engines are running normally. If NOT, the FADEC will windmill the prop at 100 percent. If all engines flameout atleast one inboard will windmill to supply electric and hydraulic power.
If a flameout is detected, the FADEC initiates ignition and monitors for a relight. IF relight does not occur before NG decreases below __ percent, the FADEC auto shuts off fuel to shut down the engine.
56
FADEC shuts down the engine start sequence for:
No light-off
Flameout
RPM stagnation
Manual feathering will only work when:
Only functions if the START switch is in STOP or if the power levers are at GND IDLE and low-speed ground idle is selected.
What happens when you place the PROP Control switch to feather:
The auxiliary feather pump is turned on and automatically shuts off after 20 seconds.
If NP exceeds _____ percent, the _____ _____ ____ diverts pump oil away from the PCU to allow the blade counterweights to increase blade angle and control the overspeed.
104.5 percent
propeller overspeed governor
If NP exceeds ___ percent, the FADEC reduces ____ ____.
106 percent
fuel flow
If NG exceeds ___ percent or NP exceeds ___ percent the FADEC auto shuts down the engine.
109 percent
119 percent
The ATCS schedules from __ to ___ percent of takeoff power over a __ knot range.
50 to 100 percent
40 knot
How do you override ATCS on the ground?
Pushing the autothrottle disconnect buttons on No. 1 or No. 4 power levers.
How do you override ATCS in the air?
If the WOW and ATCS is displayed, press the autothrottle disconnect button 3 times within 2 seconds to override.
What is the NIU and where is it mounted?
The Nacelle Interface Unit is mounted near the FADEC units in the Nacelle above the engine.
What does the NIU do?
1) Provides MIL-STD-1553 and RS422 comms
2) Indications of oil temp, pressure and quantity, oil cooler flap position and fuel flow
3) Controls oil cooler flap and engine/nacelle anti-ice valves.
4) Engine health and usage monitoring through the EMS.
Where is the oil tank and what are the specs?
A 20-gallon tank in each nacelle above the engine.
12-gallon oil capacity with the remaining 8 gallons for air space.
0.66-gallon dedicated reservoir for the emergency feather pump oil supply.
What does the oil system do?
Independent oil systems, one for each engine, lubricate the engine power section and GMAD/PGB.
The oil cooler augmentation system supplements normal oil cooling during extended ground operation by using __th stage bleed air when the power levers are below FLT IDLE.
14th stage
Oil cooler augmentation is operating when:
1) oil cooler flap position greater than 80%
2) oil temperature above approx 80 degrees C
3) airspeed less than 50 knots
4) Power levers are less than FLD IDLE
5) WOW switch
What happens when you place the engine start switch to STOP?
Shuts off fuel at the engine, turns off respective main tank boost pump, closes the nacelle shutoff valve. During the auto start cycle, it also closes the starter regulating and shutoff valve and deenergizes the ignition.
What happens when you place the engine start switch to MOTOR?
Motors the engine to remove unburned fuel in case of no ignition, or to cool the engine following an aborted start attempt. Opens the nacelle shutoff valve and starter regulating and shutoff valve.
What happens when place the engine start switch to RUN?
Turns on the respective main tank boost pump and opens the nacelle shutoff valve.
What happens when you place the engine start switch to START?
Initiates the start sequence and FADEC auto initiates fuel and ignition at the proper rpm. The starter regulating and shutoff valve auto close when the start cycle is complete.
BETA: A green B is displayed in the center of the HP dial when the prop blade angle is __ and ___ and the FADEC has not detected any failures preventing GRD RNG and speed below ___ KTAS
23 degrees and 10.5 degrees
145 KTAS
When is the white BETA label shown?
Below the affected engine HP display when the prop is in the beta range–blade angle is less than 10.5 degrees
What is MGT?
Measured Gas Temperature:
Measure of engine temperature.
It represents the temperature of gases at the third stage power turbine vanes.
What is NG?
Gas Generator Speed:
Measure of core engine speed.
It represents the percentage of maximum rated operating speed for the gas generator.
What is NP?
Power Turbine Speed:
Indicates the percentage of maximum rated operating speed for the propeller (or power turbine)
What is FF?
Fuel Flow:
Digital readout indicates the rate at which fuel, in pounds per hour, is being fed into the engine.
What is G PSI?
Gearbox oil pressure:
Indicates pressure of the supply oil in the propeller gearbox. Measured downstream of the gearbox supply pump.
What is E PSI?
Engine oil pressure:
Indicates pressure of the supply oil in the gas generator and power turbine section of the engine. Measured downstream of the accessory gearbox supply pump.
What is TEMP?
Oil temperature:
Indicates the centigrade temp of the oil supplied to the engine. The temp is measured at the oil tank outlet (sump)
The engines are started by using a combination of ____ and ____?
Electrical power and low pressure bleed air provided by either an external source or the APU.
Minimum bleed air pressure for sustaining a start?
22 psi.
A momentary drop below 22 psi when the starter valve opens is acceptable.
Why are the engines started in LSGI?
This preferred procedure provides a more gradual heating of the engine components. Successful starting in normal ground idle can be accomplished if req’d.
Do not select the START position if MGT is above ___ degrees C? The temp can be brought down by what?
175 degrees C
Motor the engine
Fadec aborts start for what ACAWS’s?
ENG FLAMEOUT
ENG NO LIGHTOFF
ENG STAGNATED START
Upon engine start what occurs:
1) Starter light ILLUMINATES
2) 14% NG, FADEC arms fuel and ignition control circuits. 4 seconds later, ignition is energized and the fuel latching shutoff valve opens to start fuel flow (FF indicated appx 40% NG) Start to stabilized NG is 20-25 seconds
3) Starter cutout occurs at 65% NG, and starter light extinguishes. Continuous ignition terminates at 65% NG
4) Start to NP on speed 30 secs
5) Normal hyd px within 30 seconds after NP on speed. If you dont have normal indication pull control column aft 2-3 inches.
When you abort a start what must you do before you can restart?
1) Motor engine for atleast 30 seconds if fuel was introduced.
2) MGT below 175 degrees C
3) Wait 30 seconds after NG indicates 0% NG to allow overspeed circuit to be checked
LSGI NP range
NP range is 71 to 75 percent
HSGI NP is…
99% NP
AUTO oil cooler operation on the ground…
Oil cooler flap opens when temp is >75degreesC and retracts when <60degreesC.
AUTO oil cooler operation in the air with LDG GR down…
opens when the temp is >82degreesC and retracts <76degreesC
How long must LSGI be selected before engine shutdown?
Shifted to LSGI and operated for 2 minutes to more gradually cool engine components and prolong engine life.
What type of prop is each engine equipped with?
Equipped with a Dowty R391 six-blade, coarse seeking counter-weight design, variable pitch propeller.
What comprises each prop blade?
Each blade is of composite construction featuring lightning conductors, a deicing boot, and reinforced leading edge.
The prop control components:
The pitch actuator, PCU, high pressure pump, OSG unit, aux pump, and MPU
Main fuel tank specs…
Equipped with two fuel pumps (boost pump on tank floor/transfer pump at a higher level)
#1 an #4 contain three fuel level control valves (FLCVS) #2#3 contain one FLCV
Aux fuel tanks
Bladder type fuel tanks installed in the wing center section. Ac-powered transfer pump
1 FLCV each
External fuel tanks
All-metal tanks mounted under each wing on pylons between IB and OB engines. Partially compartmented for center-of-gravity control.
1 FLCV each
Two transfer pumps in them.
Boost pump specs…
Each main tank has a 15-24 psi ac powered boost pump.
Transfer pump specs and locations…
28-40 psi ac-powered transfer pump in each main tank.
L/R aux tanks have 1 a piece
L/R ext tanks have 2 a piece with only one pump used for normal operations. (alternating use)
Fuel tank quantities:
1/4: 8310
2/3: 7657
L/R aux: 5814
L/R ext: 8901
Mains only: 31,934
Main, Aux, Ext: 61,364
What is the APU and where is it located?
Auxiliary power unit is located in the left wheelwell. It supplies air for ground operation of the Air conditioning systems and for engine starting and drives a 40-kVA ac generator.
What are the six ac buses?
Left-hand ac bus Right-hand ac bus Essential ac bus Main ac bus Essential avionics bus Main avionics bus
What drives the 4 generators?
Driven by a gear mounted accessory drive and incorporate automatic mechanical disconnects.
How are loads dispersed with generators in case a generator fails?
If one generator is failed on either wing, the load is picked up by the remaining functioning generator on the same wing. If both generators on the same wing are failed, the load is picked up by the symmetrical generators on the opposite wing.
Wing to wing, symmetrical to symmetrical
What are the six buses in the dc power system?
Main dc bus Essential dc bus Isolated dc bus Avionics dc bus Utility battery bus Avionics battery bus
Aircraft battery specs?
Two 24V, 35 Ah batteries located in a fuselage compartment forward of the crew entrance door.
Utility battery supplies power to the utility battery bus and the isolated dc bus.
The avionics battery supplies power to the avionics battery bus and to the avionics dc bus.
Hydraulic pressure for the operation of aircraft hydraulic components is supplied by:
Utility, booster and auxiliary
The utility hydraulic system supplies power to?
Wing flaps Main landing gear Nose landing gear Normal brakes Nosewheel steering Ail, Elev, Rud control boost system
What does the booster hydraulic system do?
The booster system furnishes hydraulic power to the remaining portion of the flight control boost system only.
The auxiliary hydraulic system operates?
Operates the cargo door and ramp, and provides pressure for emergency brake operation and emergency nose landing gear extension.
The utility system operates from which engine-driven hydraulic pumps?
1 and #2
The booster hyd system operates from what engine-driven hydraulic pumps?
3 and #4
The utility hyd system holds?
5.5 gallons of hyd fluid
The booster hyd system holds?
3.1 gallons of hyd fluid
The aux hyd system is ran by?
Operates from a three-phase ac, electrically driven hydraulic pump, powered by the main ac bus.
The aux system reservoir holds?
5.3 gallons of hyd fluid
The bleed air system supplies which pneumatic systems?
Engine starting system Air conditioning Cabin pressurization Leading edge ice protection Aircraft buddy start lightweight air transfer system (ABSLATS)
Compressed air is supplied to the bleed air system from the _____, or when they are not running, from either the ___ or from an ____ when the a/c is on the ground.
Engines
APU
external pressure source
Two check valves isolate the engine __th stage compressor from the bleed air manifold pressure.
10th
The BA/ECS controls?
Engine bleed air flow from the the engines at the appropriate supply pressure and temp.
If the average engine power settings are below 1,000 hp, the __th stage bleed air augmenter valve opens and regulates high pressure bleed air to a predetermined pressure schedule as a function of altitude.
14th
When wing/emp anti-ice is on and bleed air temp is less than ___degreesC, the __th stage bleed air augmenter valve opens to increase temperature but not pressure.
274degreesC
14th
Time for extension, or retraction of both nose and main landing gear?
19 seconds or less
Main landing gear system consists of?
Four wheels, two mounted in on each side of the fuselage.
The nose gear is?
A swing-type gear, extending down and aft
The aircraft is equipped with a ___ psi liquid oxygen system?
300 psi
Oxygen is supplied?
From a 25-liter liquid oxygen converter. The supply is routed from the converter through two heat-exchangers to six supply regulators in the flight station and four in the cargo compartment.
The wing and emp ice protection system is enabled when the pilots airspeed is greater than?
60 KIAS
Seating accomodations of the herc?
Ground troops?
Ground troops (wheelwell seats)
Paratroops
78
92
64
Litter/Attendant capacity?
70/6
74/2
What liferafts do we have and where are they located???
Four 20-man liferafts are stored in the top center wing trailing edge area.
Life vests how many?
10 life vests
What happens when you pull a fire handle?
1) Nacelle shutoff valve closes
2) Engine oil shutoff valve closes
3) Ext agent avail.
4) Fire ext system direction valves are positioned
5) Firewall fuel shutoff valve is closed
6) Firewall hyd shutoff valve closed
7) BAU commands the prop aux fx pump energized 20 secs
8) FADEC fx prop and shutdown eng
9) Shutoff valve in eng fuel pump and metering unit is closed
What happens when you pull the APU fire handle?
1) Control power to the APU start circuit is interrupted
2) APU fuel shutoff valve closed
3) APU door closes as rpm decreases to approx 18 percent
4) EXT agent is avail
5) fire ext syst valves are positioned
