Single Source Study Sheet - Systems Flashcards
Fuel Flow in the Engine
- Pump (engine driven)
- Fuel filter
- HMU
- Liquid to liquid cooler
- ODV
Mechanical Mixing (MMU functions)
Collective to Pitch - Compensates for rotor downwash
_Collective to Roll _- Compensates for Translating Tendency
Collective to Yaw - Torques Effect
Yaw to Pitch - Lift component of Tail Rotor
Electronic Coupling (explain to collective to airspeed to yaw)
Collective to Airspeed to Yaw - Compensates for torque effect in addition to Collective to Yaw mixing based on collective position and airspeed. FCC#2 commands yaw trim actuator 100% below 40 knots decreases until 100 knots, none above 100 knots.
AFCS five subsystems
- Trim
- FPS
- Coupled Flight Director
- SAS
- Stabilator
FPS purpose
Basic autopilot – Enhances static stability through long term rate dampening in pitch, roll, and yaw. When coupled with Trim, FPS has 100% control authority (10% per second).
FPS Below 50 knots and above 50 knots
_Below 50 Kts _ _Above 50 Kts _
Att. Hold ** Pitch ** Att. Hold
Att. Hold ** Roll ** Att. Hold
Hdg Hold **Yaw ** Head Hold/Turn coord
These systems must be on and operational for FPS to function at 100%
- SAS 1 and/or SAS 2
- SAS/Boost
- Trim
- Stabilator (helps, but not req.)
Trim purpose
Provides a gradient and detent holding force for pitch, roll, collective, and yaw.
**Trim consist of **
- 3 electromechanical actuators (collective, roll and yaw),
- 1 electrohydromechanical actuator. (pitch) (SAS/Boost required for operation.)
Trim slip clutches require ___ lbs of force during an actuator jam.
Yaw ___
Roll ___
Coll ___
80 lbs max in yaw,
13 lbs max roll,
22 lbs max collective
FCC monitors continuously, will turn off driving trim actuator.
AVCS purpose
Reduces cockpit and cabin vibrations by mechanically generating additional vibrations that are out-of-phase with the main rotor (90-105 NR).
Uses 3 Force Generators
SAS 1&2 purpose
Provides short term rate dampening in pitch, roll, and yaw axis.
SAS 1&2 enhances (1)_________ & (2)___________
(3)___________ Control authority ((4)_____________).
Controled by (5) ______________
- ) turn coordination >50 kts.
- ) Hover augment <50 kts.
- ) 5% control authority each.
- ) (total 10% control authority)
- ) respective FCC computer.
SAS Input:
- Pitch,Roll, and Yaw signals from respective EGIs (Nose)
- Airspeed – Air Data Computers
Malfunction indicated by erratic movement, Reset CPTR1/ 2, or turn off that SAS
Stabilator purpose
Variable angle of incidence airfoil that enhances the handling qualities in the pitch axis in forward flight.
Stabilator functions
- Streamlines w/ rotor downwash at low speed (below 30 kts) to min. nose up attitude from downwash. (ADC, FCC)
- Collective Coupling to min. pitch attitude excursions due to collective inputs. (Collective Pos. Transducers) begins@30kts
- Angle of Incidence decreases above 30 kts. to improve static stability. (ADC, FCC)
- Lateral Sideslip to pitch coupling to reduce susceptibility to gusts. Stab up for right pedal, stab down for left pedal. (Lat. accelerometers)
- Pitch Rate Feedback to improve dynamic stability. Dampen pitch excursions due to turbulence or “G” forces. (EGI, FCC)
ODV functions
- Hot Start Prevention shuts fuel flow at 900°C.
- Over-speed protection (NP) from DEC at 120+1%
- Purges main fuel manifold and allows back flow of high-pressure air for purging.
- Sends fuel through manifold to injectors for starting & eng
HMU purpose
Basic fuel control; high press. fuel pump & variable geometry servo-actuator.
HMU functions acronym
PM CAN VDTO
HMU functions “PM”
Pumps fuel at high pressure
Meters fuel to ODV in response to PAS, LDS, torque motor from DEC, & engine variables.
HMU functions “CAN”
Collective Pitch Compensation through the LDS. When the collective is moved, NG is reset for immediate NP response.
Accel/Decel fuel flow limiting preventing compressor stalls, engine damage, or flame out.
NG limiting - limits max torque available under low temperature conditions.
HMU functions “VDTO”
Variable Geometry Positioning of the inlet guide vanes for optimum performance.
DEC lockout PAS Overide & Control with DEC inoperative. Allows pilot to mechanically bypass torque motor inputs.
Torque Motor to Trim NG Output. to fine tune engine output. Can be over ridden in DEC lockout.
Opens Vapor Vent for manual HMU priming, to remove air from HMU.
DEC purpose
Controls electrical functions of engines and transmits operation info to the cockpit.
DEC functions acronym
IN FLT HHOT
DEC functions “IN”
- Isochronous NP Governing. DEC will maintain
Np reference
- NP Reference from the cockpit, (INCR/DECR
from 96-100%)
DEC functions “FLT”
- Fault Indication. DEC code sent to corresponding ENG Q indicator and the FMS DEC status page.
- Load Sharing/Torque Matching. Increase Q of low side to match up to 3% NP above reference.
- Transient Droop Compensation. 4-1 improvement to compensate for transient rotor droop. Uses coll. Pos. transducer signal.
DEC functions “HHOT”
- History Counter. Sends signals to History Counter.
- Hot Start Preventer. Tells ODV to shut off fuel when 900°C is reached, Ng<60, Np<50.
- Overspeed Protection. Triggered when Np reaches 120±1%.
- TGT Limiting. Limits fuel flow when reaching appx. 879 Dual Eng, 903 (21⁄2 min) when opp Q is < 50%.
Engine Alternator functions
Three windings for three functions:
- Ng signal to cockpit tachometer. (green)
- Ignition power to the exciters during start. (yellow)
- DEC power. (yellow)
Loss of alt. does not result in high side failure
Weight-On Wheels Switch functions acronym
CHAFF AIM TUBE
Weight-On Wheels Switch functions “CHAFF”
- CVR/FDR: IBIT, erase on gnd
- Hydraulic leak test disabled in fight.
- Audio for low NR disabled on the ground.
- Flight Dir. Modes enabled in-flight
- FMS-Model acft, EGI GC or GPS alignment IBIT on ground/ EGI air alignment in flight
Weight-On Wheels Switch functions “AIM”
- AFCS Pitch, Roll Att hold/ Hdg hold/ Maneuvering Stab/ Rad Alt hold/ Airspeed hold – Enabled in-flight.
- IFF Mode 4-Auto Zeroize enabled in flight.
- MFD status page activation on ground
Weight-On Wheels Switch functions “TUBE”
- Thermal protection for B/U pump enabled on the ground.
- Underfreq. protection disabled in flt. (right switch)
- B/U Pump Auto ON regardless of switch position enabled in flight. Disabled on gnd unless Acc Low
- ESSS jettison disabled on ground. (right switch)
1 and #2 FUEL LOW
Lights, Switches, & MISC
#1 and #2 FUEL PRESS Fuel filter bypass pop
Fuel Boost pump
1 and #2 FUEL LOW≤ 172 pounds
Fuel filter bypass pop = 8-10 psid
Fuel Boost pump = 25 psi
1 and #2 RSVR LOW
**_Lights, Switches, & MISC _** #1 and #2 PRI SVO PRESS
BOOST SERVO OFF
1 and #2 RSVR LOW ≤ 60% cap.
#1 and #2 PRI SVO PRESS ≤ 2000 psi BOOST SERVO OFF ≤ 2000 psi
1/ #2 Hyd Impd byp. =
**_Lights, Switches, & MISC _** #1/ #2 Hyd return bypass =
Hyd. System pres. =
Pilot Assist pres reducer btn pops =
Utility mod. velocity fuse >
1/ #2 Hyd return bypass = 100±10 psid
Hyd. System pres. = 3000 psi
Pilot Assist pres reducer btn pops = 1375 psi
Utility mod. velocity fuse > 1.5 gpm
1 and #2 ENG INLET ANTI-ICE
_Lights, Switches, & MISC _
XMSN OIL PRESS
Hyd pump temp labels
1 and #2 ENG INLET ANTI-ICE 93°C
XMSN OIL PRESS < 14±2 psi
Hyd pump temp labels > 132°C (270F)
**_Lights, Switches, & MISC_** #1/#2 ENG OUT light/audio
NG LOW ROTOR RPM light/audio
NR Lose Main GENs on gnd
NR Lose Main GENs in air
1/#2 ENG OUT light/audio <55%
NG LOW ROTOR RPM audio/lt <96% NR
NR Lose Main GENs on gnd 93-95% NR
NR Lose Main GENs in air 85-89% NR
_Lights, Switches, & MISC _
Gravity Refuel:
Pressure Refuel:
Closed Circuit:
Gravity Refuel: 360gal
Pressure Refuel: 359gal, 300gpm, 55psi
Closed Circuit: 356gal, 110gpm, 15psi
_Lights, Switches, & MISC (wrong **edit with -10**)_
Eng Anti-ice on: #% Tq +## lbs/hr
Cockpit Heater on: #% Tq +## lbs/hr
Engine Idle fuel @ sea lvl ## lbs/hr
Engine Idle fuel @ 5000ft ## lbs/hr
Engine Fly fuel @ sea lvl ## lbs/hr
Engine Fly fuel @ 5000ft ## lbs/hr
Eng Anti-ice on: 20% Tq +100 lbs/hr
Cockpit Heater on: 5% Tq +20 lbs/hr
Engine Idle fuel @ sea lvl 322 lbs/hr
Engine Idle fuel @ 5000ft 277 lbs/hr
Engine Fly fuel @ sea lvl 552 lbs/hr
Engine Fly fuel @ 5000ft 479 lbs/hr