Systems 2 check on learning Flashcards
TGT will be indicated on the Power Pod when?
- TGT greater than 793°
- Difference of 75° or more
- Engine Out (Ng <55%)
- When does NG appear on the power pod?
When NG exceeds 100%
- What are the primary functions of the overspeed drain valve?
Hot start prevention, Overspeed protection, Purges fuel, Sends fuel to 12 injectors
- The ____________ provides added protection from heat-seeking weapons’ systems by mixing hot exhaust with rotor downwash.
UES
- What drives LRUs on accessory gearbox?
NG
- What drives Np governing?
DEC, ODV
- What are the 3 main functions of the DEC?
- TGT limiting
- Torque matching and load sharing
- Np governing
- Over servicing is not possible because extra oil will do what?
Flow out the filler port
- The pneumatic start system uses an air turbine engine start motor for?
Engine starting
- Where must the engine oil level be in flights over 6 hrs.?
Full mark
- Oil from the chip detector passes through the oil cooler and is cooled by?
Transferring heat from the oil to fuel
- How is the gas generator turbine connected to the accessory gear box?
Mechanically
- The HMU operates what part of the compressor section?
Variable guide veins
What controls the electrical function of the engine and transmits systems information to the cockpit?
DEC (digital electronic control)
- What is the DEC powered by?
Alternator or aircraft power
- The EDECU will display a torque signal of?
25%
- What section of the engine mechanically drives NR?
Np
- Is Ng mechanically linked to Np?
No
- What is the connection of Np and Nr?
1- way mechanical connection via the freewheeling unit
- Name the 4 modules of the engine
Cold, Hot, Power Turbine, and Accessory Gearbox
- What drives the Accessory Gearbox?
Gas Generator (at a variable speed)
- How many stages are in the compressor section?
6 (5 Axial, 1 Centrifugal)
- What operational section of the engine drives the rotors?
NP (power turbine) (it’s a one way mechanical free-wheeling unit)
- What are the 2 operational sections of the engine?
Ng and Np
- How does engine oil cooling occur?
- Liquid to liquid cooler
- oil flow through the scroll vanes
- What is the service capacity for engine oil?
7 qts
- Where is the oil drawn from for the emergency oil system?
Sumps A and B
- How does the oil system overcome high pressure during cold starts?
- Oil filter bypass valve
- liquid to liquid cooler bypass valve
- Where does the engine receive its electrical power?
Engine Alternator
- The engine alternator supplies AC power to what?
The ignition exciter and DEC/EDECU
- When does the DEC go into the 2.5-minute limiting?
When one engine is 50% below the torque of other engine
- How does the cockpit receive the Ng signal?
From the Ng winding of the alternator
- If Ng signal is lost, what happens?
Engine Out warning light, audio, and 0% Ng
- Why does the fuel system operate on negative pressure?
It lessens the potential of fire in the event the fuel system is damaged
- What function of the DEC keeps NP at 100%?
NP governing
- Ng governing is influenced by what input to the HMU?
T2 sensor
- When will TGT Limiting not work?
Lockout, compressor stall, start up
- What is variable geometry and how does it work?
HMU controlling airflow in the engine depending upon power demand
- Is the APU capable of starting both engines simultaneously?
Yes, within certain ambient temperature ranges
- When will fuel flow be automatically shut off to the engine during the start sequence (Hot start prevention)?
When TGT reaches 900 Degrees Celcius, NG at ≤60%, NP at ≤50%
- Explain Hot Start prevention:
It’s a function of the DEC and ODV that automatically prevents over temp during starts by shutting down the engine
- What does ODV do?
- Sequences fuel and sends it to the injectors (last stop of fuel
- Np overspeed protection (120% +-1)
- purges fuel on shut down
- What is the air sce/ht start switch do when on apu?
Uses air from APU to start the main engines
- What is the air sce/ht start switch do when on eng?
Uses air from the engine to provide cabin heat
- With one engine operating, what Ng and Nr must be maintained to cross bleed start the other?
90 % and 100%
- How do you manually disengage the starter?
Pull down on the PCL
- What controls air fuel mixture?
HMU through fuel scheduling
- If power is lost to the engine, will the DEC still remain functional?
Yes, it is also supplied from the AC airframe power
- Which circuit in the DEC is not powered by the alternator?
Hot Start Prevention
- When is engine Inlet Anti-Icing system available?
- 4°C and below it must activate
- May or may not activate between 4°and 13° C
- Not available 13 C and above
- Other than bleed air, what is used to assist in the engine anti ice functions?
Hot engine oil provides a passive anti ice function
- How is torque affected when anti-ice switch is ON?
You can lose up to 20% torque available, additional 5% with heater on
- How do you recognize a compressor stall?
Loud popping/banging accompanied by rapid increase in TGT and fluctuations in NG, Q, NP
- Describe the fuel flow:
- Pump
- Fuel filter
- HMU
- Liquid to liquid cooler
- ODV and nozzles
- Describe the load demand system:
Provides mechanical input directly from the collective output of the flight control mixer to the engine HMU to reduce transient engine and NR droop
(Reduces transient engine and NR droop)
1.Where is the pedal adjust handle located?
On the side of the instrument panel.
- Which cockpit control has a telescoping (extend/retract) feature?
Co-pilot’s collective
Outputs from cockpit controls are carried by mechanical linkage through the pilot assist servos to the
Mechanical Mixing Unit
- On which panel can you find both the TAIL SERVO and BACKUP HYD PUMP switches?
MISC SWITCH panel
- The MMU is designed to reduce
Inherent Control Coupling
- Name the four mechanical mixes provided by the MMU.
Collective to Pitch
Collective to Roll
Collective to Yaw,
Yaw to Pitch.
- Describe Collective to Pitch—
MMU put fwd input into rotor disc to prevent nose-high attitude
(Prevents nose high attitude)
- Collective to roll –
MMU makes left rotor disc input to compensate for translating tendency
(Compensates for translating tendency)
- Collective to Yaw –
MMU inputs left pedal to compensate for torque effect
compensates for torque effect
- Yaw to pitch –
Aft input to M/R system as T/R pitch is increased. It compensates for vertical thrust
(Compensates for Vertical Thrust]
- Collective/Airspeed to Yaw—
As collective and A/S increase, T/R pitch decreases and visa versa.
- The SERVO OFF switch has an ___ _____ to prevent both servo stages from being turned off
– Electrical interlock
- With a leak, it takes how many seconds to lose both systems?
– 11-13 seconds
- Servos are the only thing that can______?
Jam or Hardover
- How does the MMU minimize inherent control coupling?
By combining, summing, and coupling collective, yaw, pitch and roll inputs
What is the only trim actuator that receives hydraulic power from the number 2 hydraulic system?
Pitch control
Why is Collective/Airspeed to Yaw mixing completely phased out when the airspeed is above 100 kts?
Due to the efficiency of the tail rotor and cambered fin.
- Moving the SERVO OFF switch from NORM to 1 st STG or 2 nd STG will?
Turn off that stage of primary servos
- What is the reason for the depressurization valve to only connect to the Backup Pump?
Reduce output pressure of the pump when starting the electric motor.
The No. 1 hydraulic system supplies hydraulic fluid through its transfer module to what servos?
The first stage primary servos and first stage tail rotor servo.
- HYD LEAK TEST switch allows testing of the ____. –
LDI
- What HYD pump is the depressurization valve connected to? –
Backup HYD Pump
- The RSVR 1/2/Backup LOW caution illuminates when?
When there is 60% fluid remaining in the reservoir (leak in the system).
- If a tail rotor cable breaks, what caution and/or advisory would appear?
T/R QUAD FAIL caution
- The No. 2 hyd. system supplies pressure through the transfer mod to what servos?
The second stage primary servos and pilot-assist servos.
BOOST SERVO OFF caution indicates what?
Loss of hydraulic pressure to the collective and/or yaw boost servo.
- What is the purpose of the APU Accumulator?
Provide a hydraulic charge to the APU start motor.
- In flight, the backup pump mode automatically sets to?
The AUTO mode even if the switch is in the OFF or ON position.
- What does the backup pump supply pressure to?
- No. 1 and/or No. 2 hydraulic systems
- Second stage tail rotor servo and APU accumulator.
- Name the trim actuators. –
Yaw, roll, collective and pitch
- What FCC drives the trim actuators? –
FCC #2
- What five lights illuminate when the backup hydraulic pump is on?
RES 1 LOW HYD PUMP 1 HYD PUMP 2 T/R SERVO 1 T/R SERVO 2 ON and APU ACCUM LOW
Two central components of the AFCS?
FCCs
What does the AFCS do?
It enhances the stability and handling qualities of the helicopter and provides autopilot functions.
- What FCC sends signals to the trim actuator?
FCC 2
- What are the five basic subsystems of AFCS?
Stabilator SAS Trim Flight Path Stabilization (FPS) Flight director (FD)
What are the additional features of AFCS?
Heading hold
Pitch and roll hover augmentation/gust alleviation
Turn coordination
Fault detection and annunciations
- What are SAS actuators used for?
Used to enhance aircraft short term dynamic stability
- What axis does SAS work in?
pitch, roll, yaw
- When does SAS 1 and 2 enhance turn coordination?
When the FCC compute data at airspeeds above 50 kts
What provides long term inputs by trimming the flight controls to the position required to maintain selected flight attitude?
Outer loop—collective, pitch, roll and yaw (Trim)/FPS
- What are the five basic subsystems that comprise AFCS?
Stabilator, Trim, SAS, FPS, and Coupled FD .
- What type of Stability is Static associated with, Short or Long Term?
Long Term
- What will the FCCs do if A/S signal is lost?
Shut off
- What is the control authority of the outer loop trim?
100% (10% per second)
- Is heading hold an inner or outer loop function?
It is an outer loop, because it operates through the yaw trim actuator
- What is required for proper operation of the FPS?
SAS/BOOST, TRIM and SAS1 and/or SAS 2 functions have been selected on the AUTO FLIGHT CONTROL panel
When is the heading hold reengaged following a turn when what following conditions are maintained for 2 seconds?
Roll attitude is within 2 degrees of wing level and yaw rate is less than 2 degrees per second
- When will a heading hold be captured in a hover?
When yaw rate reaches zero, not when pedal switches are engaged
- What are the four signals used by the FCCs to position the Stabilator?
C L A P
Collective stick position sensors
Lateral Accelerometers
Airspeed signals from the ADC’s
Pitch rate signals from the EGI’s
- Describe the Stabilator.
A variable angle of incidence airfoil that enhances handling qualities in the pitch axis in forward flight
- What are the stabilator functions?
SCLAP
● Streamlines – compensates for rotor downwash
● Collective coupling – minimize pitch excursions due to collective inputs
● Angle of Incidence – Angle of Incidence decreases as airspeed increases
● Lateral Sideslip – Sideslip to pitch coupling to reduce susceptibility to gusts
● Pitch Rate – pitch rate feedback to dampen pitch excursions
● Air data computer – Connected to pitot static system
- Where does the Stabilator derive its pitch information?
The EGIs.
What employs rate damping to improve helicopter stability, 10% control authority, fast in response, and can operate without causing movement of the flight controls?
Inner loop (SAS—pitch, roll and yaw)
- What are the two cautions and one advisory associated with the Stabilator?
STAB MANUAL MODE, STAB UNLOCKED, STAB DEGRADED
- Basic autopilot functions are provided by?
Trim/FPS
- The FPS will maintain and provide the helicopter with what at a/s above 50kts?
Pitch and roll attitude, airspeed and heading during cruise flight, and provide a coordinated turn feature
The ______________ caution indicates the majority of AFCS has shut down.
AFCS FAIL
- What does the SAS DEGRADED advisory mean?
The SAS pitch, roll, or yaw channel has disengaged.
- What does the STAB DEGRADED advisory mean?
The stabilator is in a limited auto mode.
- To attempt to clear AFCS fault indications, the pilot can_________.
Press the illuminated CPTR 1 and/or CPTR 2 button
- The collective trim beeper can be used below 50 KIAS to ________?
Change the aircraft heading
- The inner loop or SAS provides how much control authority?
5% per or 10% total
- The outer loop or Trim/FPS provides how much control authority?
100%
- What are the five basic subsystems that comprise AFCS?
Stabilator, Trim, SAS, FPS, and Coupled FD.
2.Dynamic stability is provided by?
SAS
3.Basic auto pilot functions are provided by?
`Trim/FPS.
4.The ______________ caution indicates the majority of AFCS has shut down.
AFCS FAIL
- What does the SAS DEGRADED advisory mean?
The SAS pitch, roll, or yaw channel has disengaged.
- What does the STAB DEGRADED advisory mean?
The stabilator is in a limited auto mode.
- To attempt to clear AFCS fault indications, the pilot can_________.
press the illuminated CPTR 1 and/or CPTR 2 button
- The collective trim beeper can be used below 50 KIAS to ________?
change the aircraft heading
What are the main rotor subsystems?
m/r blades, hub, flight controls, bifilar vibration absorber
- Conical Elastomeric bearings permit what movements?
Flap, lead, lag
- Cylindrical Elastomeric bearings permit what movements?
Provides the pitch change axis
- Main module chip detector has a _____ time delay to allow fuzz burn to work?
30 seconds
- The ________ accessory module has a low oil pressure switch and chip detector.
Left