1. INTRODUCTION The landing gear is a retractable tricycle type consisting of two, wing root mounted, main landing gear assemblies and a forward, fuselage mounted, steerable, nose landing gear assembly. The main landing gear assemblies retract inboard and the nose landing gear assembly retracts forward. Each landing gear has a nitrogen filled shock strut to absorb and dissipate the shock loads encountered when the aircraft lands. The landing gear subsystems are as follows: Landing gear extension and retraction Landing gear doors Alternate landing gear extension Landing gear overheat detection Brake system Brake temperature monitoring system (BTMS) Antiskid Nose wheel steering Proximity sensing electronic unit (PSEU). Landing gear extension and retraction is electrically activated by the landing gear selector lever and controlled by the proximity sensing electronic unit (PSEU). Sensors for the PSEU are mounted on the landing gear and landing gear doors. The PSEU also provides landing gear position indication for display on the EICAS. In normal operation, the landing gear is hydraulically actuated by number 3 hydraulic system. An alternate independent means of extending the landing gear is available should the normal extension system fail. Each gear assembly has two wheels and each of the four main wheels is fitted with a, hydraulically operated, steel multi-disc brake assembly. Canadair Regional Jet 100/200 - Landing Gear Page 1
Transcript
1. INTRODUCTION
The landing gear is a retractable tricycle type consisting of two, wing root mounted, mainlanding gear assemblies and a forward, fuselage mounted, steerable, nose landing gearassembly. The main landing gear assemblies retract inboard and the nose landing gearassembly retracts forward. Each landing gear has a nitrogen filled shock strut to absorb anddissipate the shock loads encountered when the aircraft lands.
The landing gear subsystems are as follows:
� Landing gear extension and retraction
� Landing gear doors
� Alternate landing gear extension
� Landing gear overheat detection
� Brake system
� Brake temperature monitoring system (BTMS)
� Antiskid
� Nose wheel steering
� Proximity sensing electronic unit (PSEU).
Landing gear extension and retraction is electrically activated by the landing gear selectorlever and controlled by the proximity sensing electronic unit (PSEU). Sensors for the PSEUare mounted on the landing gear and landing gear doors. The PSEU also provides landinggear position indication for display on the EICAS. In normal operation, the landing gear ishydraulically actuated by number 3 hydraulic system. An alternate independent means ofextending the landing gear is available should the normal extension system fail.
Each gear assembly has two wheels and each of the four main wheels is fitted with a,hydraulically operated, steel multi-disc brake assembly.
Canadair Regional Jet 100/200 - Landing Gear
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NOSE LANDINGGEAR FORWARDDOORS
NOSE LANDINGGEAR AFT DOOR
RIGHT MAINLANDING GEAR
LEFT MAINLANDING GEAR
MAIN LANDINGGEAR BAYS
LEFT MAIN LANDINGGEAR DOOR
NOSELANDINGGEAR
Canadair Regional Jet 100/200 - Landing Gear
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1. NOSE AND MAIN LANDING GEAR
Normal extension or retraction of the landing gear is initiated by landing gear control leverselection. The retraction or extension signal is sent to the proximity sensing electronic unit(PSEU) which monitors various landing gear proximity sensing inputs and weight-on-wheelsinputs. If the correct parameters are met, the PSEU energizes a selector valve to retract orextend the landing gear using No. 3 hydraulic system.
The landing gear control lever is equipped with a solenoid lock which prevents an upselection of the landing gear control lever with the aircraft on the ground. In the event of asolenoid lock malfunction, a downlock release (DN LCK REL) on the landing gear controlpanel, permits up selection of the landing gear control lever by overriding the solenoid lock.
Retraction and extension of each landing gear is driven by a retract/extend actuator.Tension springs assisted by a downlock actuator ensure that the main gear locks in thedown position. The lock is released at the start of the retraction cycle. An uplock assemblylocks the main gear in the retracted position. An uplock release actuator releases the uplockassembly at the start of the extension cycle.
The nose landing gear (NLG) is hydraulically extended in the aft direction and mechanicallylocked in the down position. The NLG is hydraulically retracted in the forward direction andmechanically locked in the up position.
The main landing gear doors and the nose landing gear aft door are mechanically linked tothe respective landing gears, and therefore, retract and extend with the landing gears. Thenose landing gear forward doors are actuated hydraulically from No. 3 hydraulic system.The nose landing gear forward doors open before extension and retraction and then closeafter extension and retraction.
OPEN -- opens nose landinggear doors and disables thenose landing gear door selectorvalve. The nose landing geardoors will remain open with orwithout hydraulic power, aslong as the switch is inthis position.FLT/NORM -- closes noselanding gear doors andenables the nose landinggear door selector valve,provided there is hydraulicpower.
External Service Panel
CAUTION
Ensure that the nose landing gear bay area is clearbefore selecting the nose door switch to FLT/NORM.
EXT ACPUSH
CKPT CALLPUSH
HDPH
MICLAMPTEST
PKG BRKON
BATTON
AVAIL
IN USECALL
APUSHUT--OFF
NOSEDOOR
OPEN
FLT/NORM
Canadair Regional Jet 100/200 - Landing Gear
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For landing gear retraction,Once the aircraft is airborne, with no weight-on-wheels signal, the PSEU commands andmonitors the following events:
� The landing gear control lever solenoid downlock is released to permit UP selection of thelanding gear control lever
� The nose landing gear doors selector valve is energized, to open the forward noselanding gear doors
� The nose landing gear and main landing gear selector valves are energized to releasethe downlocks and the main and nose landing gears retract. Hydraulic pressure from thenose landing gear up-line is routed to activate the brake control valves to stop main wheelrotation
� Uplocks of the nose landing gear and main landing gear are engaged to secure thelanding gears in the retracted position
� The nose landing gear doors selector valve is energized, to close the forward noselanding gear doors.
NOTE
The nose landing gear wheel well area can beinspected by opening the forward nose landing geardoors, through selection of the NOSE DOOR switchon the External Service Panel.
For landing gear extension,The PSEU commands and monitors the following events:
� The landing gear control lever is manually selected to the DN position
� The nose landing gear doors selector valve is energized, to open the forward noselanding gear doors
� The nose landing gear and main landing gear selector valves are energized to releasethe downlocks and extend main and nose landing gears
� Downlocks of the nose landing gear and main landing gear are engaged to secure thelanding gears in the extended position
� The nose landing gear doors selector valve is energized, to close the forward noselanding gear doors.
Ground lock pins are inserted by ground crew to prevent inadvertent retraction of the landinggear when the aircraft is on the ground.
Canadair Regional Jet 100/200 - Landing Gear
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Landing GearControl LeverDown Lock(lever solenoid)Used to preventinadvertent landinggear up selectionwhen on ground.When airborne, aWOW signalcompletes a circuitwhich disengagesthe lock and permitsgear up selection.
Landing Gear Control PanelCentre Instrument Panel
Landing GearControl Lever DownLock Release LeverUsed if there is afault in the solenoidrelease circuit.Move switch downand hold down tomanually override theLDG GEAR controllever solenoid lock.
LDG GEAR
HORNBTMS OVHTWARN RESET
OFF
ARMED
ANTI SKID
DN LCKREL
OVHT TESTWARN FAIL
MLG BAYOVHT
UP
DN
MUTED
TEST
Landing Gear LeverControls retraction andextension of the landinggear. Lever must bepulled out to be movedto alternate position.
UP -- Retracts landing gear.DN -- Extends landing gear.
Mute HornSwitch/LightMutes landing gearwarning horn. Whitelight will come on toindicate that landinggear warning hornhas been mute.
Canadair Regional Jet 100/200 - Landing Gear
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Landing Gear Manual Release HandleCenter Pedestal
MANUALRELEASE
LANDINGGEAR
PUSH FULLY TO STOW button (red)Used to reset the manual release system(stow the LG PULL handle):Hold handle, press button and then slowlyreturn handle to the stowed position.
LANDING GEAR MANUAL RELEASEhandle (red)
Used to manually lower the landing gear:Pull handle and hold handle in the fullyextended position until EICAS indicates thenose and main landing gear are in thedown and locked position.
NOTE
Considerable force is required tooperate the landing gear manual releasesystem.
NOSE DOOR OPEN Warning (red)Indicates that nose landing gear bay doors areopen for more than 10 seconds after gear haslocked or with airspeed greater than 250 kt.
NOSE DOOR
GEAR DISAGREE Warning (red)Indicates that landing gear position does notagree with landing gear selector lever position.
GEAR DISAGREE
GEAR DISAGREE
HORN MUTEDStatus (white)Indicates that landinggear warning hornhas been manuallymuted.
<0006>
<0039>
Canadair Regional Jet 100/200 - Landing Gear
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Primary Page
<0039>
<0006>
Landing Gear Position IndicatorUP (white) -- Indicates that respectivelanding gear is in the up and locked position.DN (green) -- Indicates that respective landinggear is in the down and locked position.
(amber) -- Indicates that respectivelanding gear is in transition.(red) -- Indicates that respectivelanding gear is not safe.(amber dashes) -- Indicates thatrespective landing gear is inunknown position.
”Landing Gear Warning Horn”Comes on to warn that the landing gearare unsafe if:
Airplane is below 1,000 AGL, andRate of descent is 400 fpm, andLanding gear are not down and locked.
NOTE
The gear symbols and flap position indicatorscome on whenever the landing gear warninghorn is active.
<0039>
NOTE
The amber gear symbols will flash if thelanding gear warning horn is on for morethan 10 seconds.
<0039>
TOO LOW GEAR (Aural warning)Is heard if any landing gear is not downand locked with the radio altitude lessthen 500 ft AGL and the indicatedairspeed is less than 190 knots.
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The PSEU monitors the position of the landing gears, nose landing gear doors and theuplocks and downlocks. Landing gear position is displayed on the EICAS primary page.The gear position information is removed from the primary page 30 seconds after the gear isup and locked.
A. Landing Configuration Warning
The landing gear warning horn will sound if:
� 2 minutes after ground to air transition, any landing gear is not down and locked,and
� The indicated airspeed is less than 163 knots with one or both thrust levers selectedto IDLE, or
� The indicated airspeed is less than 185 knots with the flaps at less than 5� and oneor both thrust levers selected to IDLE.
NOTE
1. The landing gear warning horn may be muted with one thrustlever at IDLE and the landing gear not in the down and lockedposition.
2. The landing gear warning horn cannot be muted when the flapsare selected to greater than 30�, or both thrust levers are setto IDLE.
3. The landing gear warning horn is inhibited during take--offwindshear conditions.
4. The landing gear warning horn will not sound during a radioaltimeter test in flight and the horn is inhibited during take--offwindshear conditions. <0039>
B. Alternate Landing Gear Extension
Should a failure occur in the landing gear control system or in hydraulic system 3,landing gear extension is still possible by pulling the landing gear manual releasehandle.
When the handle is pulled, the nose landing gear forward door camlock and the threelanding gear uplocks are released by mechanical means. At the same time theassociated dump valves are opened to route No.3 hydraulic system pressure to returnwhich permits the landing gear to extend under its own weight.
The main landing gear is assisted to the down-and-locked position by the main geardown lock assist actuators which are powered by No.2 hydraulic system. The noselanding gear is assisted to the down-and-locked position by two tension springs and byairflow.
C. Wheels and Tires
Each wheel has a pressure relief plug (overpressure valve) and an inflation valve.�, �� �$ '� �,� �������� ������ ,� �� � � ��-� �%��.
Canadair Regional Jet 100/200 - Landing Gear
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Four heat sensitive fusible plugs are installed in each main wheel to release excessiveair pressure caused by heat build--up. The fusible plugs protect the main wheel tiresfrom bursting, that could occur under heavy braking activity.
The proximity sensor system (PSS) includes the proximity sensor electronics unit (PSEU)and associated proximity sensors, proximity switches and microswitches installed throughoutthe aircraft. The PSS provides five basic functions:
� Normal landing gear positioning control,The PSS provides the signals that command the landing gear to extend and retract andthe nose gear doors to open and close.
� Landing gear position indication,
The PSS monitors landing gear position and provides indication and position status to theEICAS.
� Weight-on-wheels indication,
The PSS monitors landing gear strut compression and provides indication of air or groundstatus to the aircraft systems that require the information.
� Fuselage door indication,The PSS monitors the fuselage door positions and provides inputs to the EICAS forindication on the primary page, status page and door synoptic page. (refer to Chapter 6).
� Thrust reverser indication,The PSS monitors and reports to EICAS the (stowed/unstowed) status of the left andright thrust reversers (refer to Chapter 20).
The PSEU, after processing sensor inputs, generates outputs that are used to control thelanding gear position. The PSEU also reports system status and provides control data toother aircraft systems.
Continuous and periodic tests are performed by the PSEU to monitor specific aircraftsystems health and status. Landing gear position and status are displayed on the engineindication and crew alerting system (EICAS) primary page. The landing gear positionindication is removed 30 seconds after the landing gear is in the up and locked position withthe flaps at 0 degrees.
Canadair Regional Jet 100/200 - Landing Gear
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ATTITUDE HEADINGREFERENCE SYS
AIR TRAFFIC CONTROL
TRANSPONDERS 1,2
TRAFFIC ALERTCOLLISION
AVOIDANCE SYS
GROUND PROXIMITY
WARNING SYSTEM
FLIGHT DATA
RECORDER
DATACONCENTRATOR
UNITS
SPOILER ELECTRONICCONTROL UNITS
(1A--1C, 2A--2C)
NOSE WHEEL
STEERING:
. DOWN LOCK
. WOW 1,2
CABIN PRESSURE
CONTROLLER
AVIONICSCOOLING SYS
CLOCK
GEAR HANDLE
DOWNLINK
SIGNS:. NO SMOKING
. FASTENSEAT BELT
NOSE GEAR
SOLENOIDS:
. EXTEND
. RETRACT
MAIN LANDING
GEARSOLENOIDS:
. EXTEND
. RETRACT
DOOR SELECTVALVE:
. OPEN
. CLOSED
COMMUNICATIONS:
COCKPITVOICERECORDER
INTERCOM
WOW1
WOW2
LGC/
DOOR
LGC/DOOR
DC BAT
DC BAT
DC BAT
DC BAT
DC BUS 1
DC BUS 2
DC ESS BUS
DC BUS 1
SENSORS
INBD GROUNDSPOILER STOWED
OUTBD GROUNDSPOILER STOWED
PARK BRAKESOV CLOSED
MAIN LANDING
GEAR:
. WOW 1,2
. UPLOCK
NOSE GEAR:
. WOW 1,2
. DOWLOCK 1,2
. UPLOCK
. OLEO EXTEND
NOSE DOOR:
. L/R CLOSED
. UPLOCK
DOOR CLOSED:
. COCKPIT EMERG
HATCH
. AFT EQPT
BAY DOOR
. OVERWING
DOORS LH/RH
. AVIONICS BAY
. SERVICE/EMERG
. BAGGAGE
COMPARTMENT
HANDLE LOCKED:
. PAX DOOR
INNER/OUTER
. SERVICE/EMERG
INNER/OUTER
. BAGGAGE
COMPARTMENT
. AVIONICS BAY
DATA
FLAPS >0,
>30
CABIN PRESSURE>10,000
PARK BRAKE
SOV ON
THRUST LEVERS
4 DEGREES
NOSE GEAR
DOOR OPENED
HORN MUTEON
Messages:
PROXIMITY
NOSE DOOR OPEN
GEAR DISAGREE
PARKING BRAKE
PARK BRAKE SOV
HORN MUTED
PROX SYS FAULT
. DOWNLOCK 1,2COMMANDS:
EXTENDRETRACT
AURAL/VISUAL WARNING MESSAGES
Primary Page
PROXI
MITY
SENSOR
UNIT
ELECTRONICS
STALL WARNING
SYS/AOA
HORIZ STAB TRIM
CONTROL UNIT 1,2
FLAP ELECTRONICCONTROL UNIT 1,2
HYDRAULIC MOTORPUMP 1,2
ANTI SKIDINBD/OUTBD
STALL PROTECTION
SYSTEM
AIR DATA SYS--
PROBE HEATERS
FUEL SYSTEM
COMPUTER UNIT
AUXILIARY POWER
UNIT (ECU, FIRE)
THRUST REVERSER
1,2
AIR DRIVENGENERATOR
AUTO DEPLOY
UTILITY BUSSHED
IRS SYS<0025>
PAX DOOR:
PIN 1,2 LOCKEDCAM 1,2 LOCKED
<0039> <0006>
Canadair Regional Jet 100/200 - Landing Gear
Page 16
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NOTE
The WOW OUTPUTcaution message maybe accompanied bythe following:
WOW OUTPUTCaution (amber)Comes on to indicatethat WOW outputs,channel 1 andchannel 2 do notagree.
One or more of theWOW sensorsdisagree with eachother which may affectair and ground modesof operation.Expect that inadvertentoperations of WOWdependant systemsmay occur.
WOW INPUT Caution(amber)Comes on to indicatethat a WOW sensingcircuit has failed or isin disagreement withthe other sensingcircuits.
PROX SYS CHANCaution (amber)Comes on to indicatethat the normal landinggear extension/retractionsystem is inoperative.
NOTE
If landing gear extension/retraction is abnormal,GEAR DISAGREE warningmessage will not come on.WOW OUTPUT FAIL
Status (white)Comes on to indicatethat a WOW outputfault is detected in anon--critical system.
PROX SYS FAULTStatus (white)Comes on to indicatea failure in the PSEUsystem.
Status Page
WOW OUTPUT FAIL
<0039>
<0039>
PROX SYS FAULT
Primary Page
<0039>
<0006>
WOW INPUT
WOW OUTPUT
PROX SYS CHAN
<0039>
<0039>
PROX SYS FAULTStatus (white)Comes on to indicatethat the PSEU hasdetected:a sensor/internalfailure, ora loss of redundency
Canadair Regional Jet 100/200 - Landing Gear
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A. System Circuit Breakers
SYSTEM SUB--SYSTEM CB NAME BUS BAR CBPANEL
CBLOCATION
NOTES
PROX SENSLGC /D2
DC ESS 4 B13
PROX SENSLGC /D2 WOW1 & 2 DC BAT 2
P3
ProximitySensing
Landing GearControl
PROX SENSLGC /D1
DC BAT 2
P2
Sensing ControlPROX SENSLGC /D1
DC BUS 1 1
F6
PROX SENSWOW 1
DC BUS 1 1F7
PROX SENSWOW 2
DC BUS 2 2 F9
Canadair Regional Jet 100/200 - Landing Gear
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1. BRAKE SYSTEM
Each wheel of the main landing gear is equipped with self-adjusting multi-disc brakes. Thebrakes of the inboard wheels are powered by No. 3 hydraulic system and the brakes of theoutboard wheels are powered by No. 2 hydraulic system.
Brake application is initiated by pressing the rudder pedals which are mechanically linked tothe associated brake control valves. The brake control valves meter hydraulic pressure,proportional to the pedal pressure, to the four main wheel brake units, through fourindependent anti-skid control valves and four hydraulic fuses.
If a leak occurs in a brake line, the associated hydraulic fuse will close off the hydraulic line,preventing loss of the entire system fluid.
With the loss of one hydraulic system, the aircraft has 50% symmetric braking capability withfull anti-skid control to the working brakes. In the event of a failure of both No. 2 and No. 3hydraulic systems, accumulators in each hydraulic system will provide reserve pressure forsix braking applications (providing the anti--skid is selected OFF).
Available inboard and outboard brake pressure is continuously monitored and displayed onEICAS on the hydraulic synoptic page, and any abnormal brake pressure detected isdisplayed on the EICAS in the form of a visual and/or aural message.
NOTE
A brake overheat condition may trigger a MLG BAYOVHT warning message (refer to chapter 10,section 40).
During landing gear retraction, hydraulic pressure is applied to the main wheel brake controlvalves to stop main wheel spin.
Two brake wear indicator pins, installed on each brake assembly, provide a visual indicationof brake wear. If the indicator pin is flush with the top of the indicator housing, maintenanceshould be informed.
NOTE
The brake wear indicator pins must be checked withthe brakes applied and No. 2 and No. 3 hydraulicsystems on.
PARKING BRAKE ONLightComes on to indicate thatthe parking brake is set.
EXTERNAL SERVICE PANEL
EXT ACPUSH
CKPT CALLPUSH
HDPH
MICLAMPTEST
PKG BRKON
BATTON
AVAIL
IN USECALL
APUSHUT--OFF
NOSEDOOR
OPEN
FLT/NORM
NOTE
Do not apply torque to the parkingbrake handle until the parking brakehandle is in the full pulled position.Do not rotate the parking brakehandle more than 90 degrees to lock.
Canadair Regional Jet 100/200 - Landing Gear
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PARKING BRAKE
Primary Page
Status Page
PARKING BRAKE ON
<0039>
<0039>
PARK BRAKE SOV
<0006>
<0039>
PARK BRAKE SOVCaution (amber)Indicates that theparking brake SOV hasfailed or the parkingbrake SOV is in theclosed position withthe parking brakehandle off.
CONFIGBRAKES
PARKING BRAKE ONAdvisory (green)Comes on to indicate thatthe parking brake is set.
Conditions are:
<0039>
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BTMS OVHT WARN RESET SwitchPress to reset the BTMS. The BTMS can onlybe reset if the brake overheat condition or thebrake temperature difference has discontinued.
Landing Gear Control PanelCenter Instrument Panel
When a brake overheat condition is detected, the braketemperature outline and readout will remain red, regardlessof temperature value, until the system is reset by the BTMSOVHT WARN RESET switch.
BTMU FAIL Status (white)Comes on to indicate that the BTMSunit has failed.
NOTE
Brake Temperature ReadoutIndicates temperature value of respective brake.
HORNBTMS OVHTWARN RESET
ARMED
ANTI SKID
MUTED
TEST
<0039>
<0039>
Status Page
BTMU FAIL
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A. Parking Brake
Inboard brake control valves and the parking shutoff valve are used to provide brakingwhen the aircraft is parked. Pulling the parking brake handle while fully depressingboth rudder pedals and turning the handle 90 degrees in either direction, locks bothbrake control valves in the applied position.
When the hydraulic systems are shut down, hydraulic pressure slowly leaks away viathe anti-skid return lines. The parking brake shutoff valve closes when the parkingbrake is applied, ensuring that hydraulic system 3 accumulator pressure is maintainedon the inboard brakes for a prolonged period of time.
NOTE
With the parking brake applied, only the inboardbrakes will hold for a prolonged period of time if No. 2and No. 3 hydraulic systems are not available.
Parking brake configuration and operational condition are continuously monitored andany detected fault is displayed on EICAS in the form of a visual and/or aural message.
Effectivity:
� Airplanes 7003 to 7128 and 7002, 7129 and subsequent incorporating SB601R--24--055
NOTE
On the ground, with the parking brake applied, the ADG automaticdeployment is inhibited.
B. Brake Temperature Monitoring System
The brake temperature monitoring system (BTMS) provides an indication to the crew ofthe main wheel brake temperatures. Individual brake temperatures are displayed as acolor coded numerical readout on the EICAS Status page. The brake temperaturereadout will be displayed when the value of one of the four readouts is six or greater, orwhen the landing gear and flap positions are displayed on the EICAS.
A BTMS overheat warning reset switch, on the landing gear control panel, is used toreset the system when the brake overheat condition no longer exists.
C. Anti--Skid System
The anti-skid system controls hydraulic pressure to the four main wheel brakes toprovide anti-skid protection. The anti-skid system consists of a dual channel (inboardand outboard) anti-skid control unit (ASCU), four (axle mounted) wheel speedtransducers and two dual anti-skid control valves.
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The anti-skid system performs the following functions:
� Individual wheel anti-skid control: -- Prevents skids from developing
� Touchdown protection: -- Prevents landing with locked wheels in the event that thepilot(s) are depressing the brake pedals during touchdown
� Locked wheel protection: -- Allows a wheel to recover from a deep skid.
Selecting the anti--skid switch, on the landing gear control panel, to the ARMEDposition enables the ASCU (provided the parking brake is not set and both mainlanding gear are down and locked).
By monitoring each wheel speed individually, the ASCU can detect tire skidding. TheASCU independently reduces the braking pressure at the skidding wheel by modulatingthe pressure outputs of the appropriate anti-skid control valve. This modulation iscontrolled by the individual wheel speed and deceleration monitored through the wheelspeed transducers.
In the air, with no weight-on-wheels signal, the anti-skid control valves dump pressureto prevent wheel lock-up on touchdown. On the ground, the system becomesoperational once a 35 knots wheel spin-up signal is present or a weight-on-wheelssignal is present after a 5 second delay. The anti--skid function is operational to aminimum wheel speed of 10 knots.
NOTE
In the event of a failure that causes loss of braking,manual braking is restored by selecting the anti-skidsystem off.
The ASCU continuously monitors the anti-skid system and any detected faults aredisplayed on the EICAS primary page.
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A/SKID INBD Caution (amber)Indicates that the inboard channelof the anti skid system has failed.
A/SKID OUTBD Caution (amber)Indicates that the Outboard channelof the anti skid system has failed.
NOTE
Both the A/SKID INBD and A/SKIDOUTBD caution messages will come onif one of the main landing gear fails todownlock.
Anti skid Test Switch (Spring--loaded to normal position)TEST -- simulates a failure (alternately) in the outboard andinboard channels of the anti skid system.Results are displayed on EICAS.
HORNBTMS OVHTWARN RESET
OFF
ARMED
ANTI SKID
OVHT TESTWARN FAIL
MLG BAYOVHT
MUTED
TEST
Anti skid Armed SwitchARMED -- Anti skid system is armed. System is activatedwith wheel spin--up (35 kt).OFF -- Anti skid system is disabled.
A/SKID INBD
Primary Page
<0039>
<0006>
A/SKID OUTBD
NOTE
Anti skid test must be performed with the anti skid systemarmed and landing gear down and locked.
Landing Gear Control PanelCenter Instrument Panel
Canadair Regional Jet 100/200 - Landing Gear
Page 28
D. System Circuit Breakers
SYSTEM SUB--SYSTEM CB NAME BUS BAR CBPANEL
CBLOCATION
NOTES
Brakes
BRAKEPRESS IND
DC BUS 2 2 G3
Landing Gear
BrakesBRAKE TEMPMON
DC BUS 11
G3
Anti SkidANTI SKID DC BUS 1
1G4
Anti-SkidANTI SKID DC BUS 2 2 G4
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1. NOSE WHEEL STEERING SYSTEM
The nose wheel steering system is a steer--by--wire system which is electrically controlledand hydraulically actuated through dual steering actuators on the nose landing gear. Thesystem is controlled by a steering electronic control unit (ECU) and powered by No. 3hydraulic system.
The steering ECU is armed through a N/W STRG ARMED switch, located on the pilots leftside panel, and activated by a weigh--on--wheels and nose gear down--and--locked signalfrom the proximity sensing electronic unit (PSEU).
The steering ECU controls the nose wheel position based on inputs from either the steeringtiller on the pilot’s side console or the rudder pedals. Steering commands are processed bythe the ECU which electrically controls an electrohydraulic servo valve to modulate hydraulicpressure to the steering actuators. The steering tiller turns the nose wheel up to 70 degreeseither side of center, and is intended for low speed taxiing. Steering with the rudder pedalsis limited to 7 degrees either side of center and is intended for high speed taxi and take-offand landing rolls. Nose wheel position feedback is sent to the ECU from two positiontransducers mounted on the steering actuators.
After take-off, the ECU generates a signal to center the nose wheel prior to landing gearretraction. Also, centering cams in the shock strut mechanically center the nose wheel asthe strut extends under its own weight.
If a failure is detected by the steering control unit, the system reverts to free castoring mode.The pilot then maintains ground directional control through rudder control and differentialbraking.
In the event of failure of No. 3 hydraulic system, the nose wheel is centered by the centeringcams. Rudder, differential braking and differential thrust will be used for directional control.Reverse thrust and the ground spoilers will decelerate the aircraft, if the brakes aredegraded or fail completely.
The steering control unit continuously monitors the nose wheel steering system, and anydetected fault is display on the EICAS primary page. Detection of a fault, will result insteering system shutdown. The system will then revert to free castoring mode.
Canadair Regional Jet 100/200 - Landing Gear
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Nose Wheel Steering TillerPilot’s Side Console
Nose Wheel SteeringTiller (black)Used to maneuver theairplane on the ground.The nose wheel steeringsystem is armed in flightand enabled when theairplane is on the ground(gear down and lockedand WOW).
Heading Indicator andIndex Marks (white)Indicates tiller selectedto center, 70 LH or RH.Tiller is spring--loaded tocenter.
Nose Wheel SteeringSwitch
ARMED -- Nose wheel steeringis armed. Nose wheel steeringis activated with WOW.OFF -- Nose wheel is set in thefree castoring mode.
NO.3 HYDRAULICSYSTEM(FROM NOSE LANDINGGEAR DOWN LINE)
TO EICAS
RUDDERPEDALS
28 VDCBUS 1
NOSE LANDINGGEAR DOWNAND LOCKED
WOW
ELECTRONICCONTROL
UNIT
ELECTROHYDRAULICSERVO VALVE
NOSEWHEEL
STEERINGACTUATORS
28VDCBUS 2
N/W STRGARMED
OFF
PSEU
Canadair Regional Jet 100/200 - Landing Gear
Page 31
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STEERING INOP
Primary Page
<0039>
<0006>
STEERING INOPCaution (amber)Indicates that thesteering system hasfailed and reverted tofree castoring mode.
NOTE
If the STEERING INOPmessage is displayedwith the system selected off,this indicates that thesteering SOV has failed(stuck) open. The N/WSTRG must be selectedon to enable centeringof the nosewheel.
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