Landing Gear & Brakes Flashcards
What provides pressure to the Outboard Brakes?
Hydraulic System 1
What provides pressure to the Inboard Brakes?
Hydraulic System 2
How is Brake Wear detected?
By Brake Wear Pins located on each main wheel
What indicates that the brakes need replacement?
When the Brake Wear Pins are flush with the Brake Bracket Outer Face Assembly
What does a Brake Wear Pin flush with the Brake Bracket Outer Face Assembly Indicate?
The Brakes need Replacing
What is a Fusible Plug?
They are attached to the wheels, and melt to relieve tyre pressure in the event of a tyre overheat
What are the 4 Protections provided by the Brake System?
Antiskid
Touchdown
Locked Wheel
Automatic Wheel Braking
What is Locked Wheel Protection?
Maximises brake efficiency in the event of a wheel lock, by relieving hydraulic pressure
When does Locked Wheel Protection become active?
ON GROUND
Wheel Speed above 30kts
What is Touchdown Protection?
It prevents the aircraft from touching down with the main wheel brakes applied
When is Touchdown Protection deactivated?
3 seconds after WOW - ON GROUND
OR
Wheel Speed above 50kts
What is Antiskid Protection?
Prevents the tyres skidding and maximises brake efficiency for the runway surface
How does Antiskid Protection work?
It controls the hydraulic pressure applied to the brakes, if necessary reducing the pressure to recover wheel speed and prevent skidding
When is Antiskid Protection activated?
Wheel Speed above 10kts
Below what speed is Antiskid Protection deactivated?
Wheel Speed below 10kts
Why is the Antiskid Protection deactivated below 10kts?
To allow for lock and pivot on a wheel when manoeuvring/parking
What is Automatic Wheel Braking?
It prevents the MAIN gear from being retracted with wheels spinning
What Protections do the Main Wheel Brakes have?
Antiskid
Touchdown
Automatic Wheel Braking
Locked Wheel
What Protections does the Autobrake have?
Antiskid
Touchdown
Locked Wheel
What must be operational to arm the Autobrake?
The Normal Braking System
What are the 4 Autobrake Modes?
LO, MED, HI, RTO
When will the Autobrake be ARMED in RTO mode?
RTO set
ON GROUND
Below 60kts
No Faults
Thrust Levers IDLE or REV
Brake Position: Any
When will the Autobrake be ARMED in LO, MED or HI Landing Mode?
LO, MED, HI set
IN FLIGHT
Below 60kts
No Faults
Brakes not pressed
Thrust Lever Position: Any
When will the Autobrake be ACTIVATED in RTO mode?
ARMED
RTO
ON GROUND
Above 60kts
No faults
Brakes not pressed
Thrust Levers: IDLE or REV
When will the Autobrake be ACTIVATED in LO, MED or HI Landing mode?
ARMED
LO, MED, HI set
ON GROUND (WOW for more than 2 seconds)
Above 60kts
No faults
Brakes not pressed
Thrust Levers: IDLE or REV
When will the Autobrake be DEACTIVATED in RTO mode?
Any mode other than RTO set
IN FLIGHT
Faults detected at speeds below 60kts
Brakes pressed while Autobrake is being applied
Thrust levers above idle when Autobrake is being applied
When will the Autobrake be DEACTIVATED in LO, MED or HI Landing Mode?
OFF or RTO set
Faults Detected
Brakes applied (more than 20%)
Thrust levers above idle when Autobrake is being applied
What Hydraulic Systems operate the Emer/Parking Brake?
Hydraulic Systems 1 & 2
How many Full Brake Applications does the Emergency Brake Accumulator Provide?
6
Does the Emer/Parking Brake have Anti-Skid Protection?
No
How would the aircraft stop in the event of a simultaneous failure of both hydraulic systems/failure of both brake control modules?
The Emer/Parking Brake has the ability to stop the aircraft, as it has pressure accumulators separate from both Hydraulic Systems
How are the brakes controlled?
Control Modules
2 x BCM (Brake Control Modules)
1 x ABM (Autobrake Control Module)
To what are the BCMs connected and what do they control?
BCM 1 - DC ESS BUS 1, Outboard Brakes
BCM 2 - DC ESS BUS 2, Inboard brakes
ABM - DC Bus 2, Autobrake
What controls and powers the Nose Wheel Steering?
Electronically Controlled by Nose Wheel Steering Control Module
Powered by Hydraulic System 2
What are the 3 modes for operating the Nose Wheel Steering System?
Handwheel Steering
Rudder Pedal Steering
Free Wheel Steering
How do you engage the Nose Wheel Steering?
Hydraulic System 2 must be pressurised
External Steering Disengage Switch must be ENGAGED
Handwheel must be:
Pressed and released for Rudder Pedal Steering
Kept Pressed for Handwheel Steering
When is Handwheel Steering Mode Used?
Low Speed Control
Wide Turn Angles
What are the Limits of the Handwheel Steering Mode?
Max Steering Angles:
+/- 76° up to 10kts
+/- 20° up to 26kts
+/- 7° over 100kts
What Nose Wheel Steering Mode would you use for Low Speed/Wide Turn Angles?
Handwheel Steering Mode
When is Rudder Pedal Steering Mode used?
High Speed Control
Wide Angles NOT required
What is the Max Steering Angle when Rudder Pedal Steering?
+/- 7°
When is Free Wheel Steering Mode Used?
Towing
Normal Steering System Failure
Allows Steering via Rudder, Differential Brake or Asymmetric Thrust
How is Free Wheel Steering disengaged?
Pressing the Steering Disengage Button located on the AFT of both control wheels
External Steering Disengage Switch must be DISENGAGED
When is Free Wheel Steering Automatically Selected?
Failure of the AIR/GROUND Signal
Nose Wheel Angle greater than 76°
Nose Wheel Steering System Failure
How do ground personnel know when it is safe to tow the aircraft?
GREEN Tow Light on the Nose Landing Gear
- confirms that the Steering is DISENGAGED and parking & Main Brakes are NOT applied
What does a RED Tow Light on the Nose Landing Gear indicate?
External Steering Disengage Switch is ENGAGED
OR
Parking or Main Brakes Applied
How is the Landing Gear Operated and Controlled?
Hydraulically Operated
Electronically Controlled
What is a PSEM?
Proximity Sensor Electronic Module
What comprises the Air Ground Positioning System?
2 x PSEM
6 x WOW (Weight on wheels) Sensors
How many WOW sensors are there?
6 - 2 per landing gear
What happens if 2 WOW sensors on the SAME Landing Gear Fail?
Landing Gear Lever cannot be moved UP
How would you know that 2 WOW sensors have failed on the same Landing Gear ON GROUND?
LG NO DISPATCH EICAS Message
How would you know that 2 WOW sensors have failed on the same Landing Gear IN FLIGHT?
Landing Gever Lever would be stuck in the DOWN position
LG WOW SYS FAIL EICAS Message
What do PSEMs do?
Process signals from the WOW sensors to determine if the aircraft is ON GROUND or IN FLIGHT
How many doors do each of the Main Landing Gear have?
3
How many doors does the Nose Landing Gear have?
4 (2 FWD, 2 REAR)
Where are Landing Gear positions indicated?
EICAS
How many uplock sensors are there?
6 - 2 per landing gear
How many downlock sensors are there?
6 - 2 per landing gear
What happens in the event of a discrepancy between 2 sensors on the same landing gear?
The sensor in agreement with the landing gear lever position is considered VALID
Which doors remain OPEN when the Nose Wheel Landing Gear is extended?
REAR
What EICAS message would be displayed if the Nose Landing Gear doors are not properly closed?
LG NOSE DOOR OPEN
What type of landing gear does the Embraer 190 have?
Conventional Dual Wheel Unit, Retractable Tricyle Landing Gear
How is the Landing Gear normally operated?
Via the Landing Gear Lever
What happens when the Landing Gear is moved up?
RELEASES hydraulic pressure for the Landing Gear Locks
Pressurises the Respective actuators to retract the Landing Gear
What happens when the Landing Gear is moved down?
RELEASES hydraulic pressure for the Landing Gear uplocks and for the retraction actuators
How is the Landing Gear held in place when retracted?
Uplocks
How is the Landing Gear held in place when extended?
Downlock Springs
When is the Landing Gear Lever locked mechanically in the down position? (Cannot put the gear up)
If PSEM detects WOW on GROUND
OR
Failure of 2 WOW Sensors on the same Landing Gear
What happens if the shock absorber of a landing gear does not fully extend?
PSEM keeps computing ON GROUND
What is the purpose of the down lock release button?
Manually releases the Landing Gear Lock so that the gear can be retracted
When would the Down Lock Release button be used?
In the event of an emergency where retraction is necessary for climb performance
How is alternate gear extension achieved if the landing gear lever fails?
Electrical Override Switch (located in the Alternate Gear Extension Compartment) which bypasses the PSEM to extend the Landing Gear
How is alternate gear extension achieved if the hydraulic system fails?
Alternate Gear Extension Lever (located in the Alternate Gear Extension Compartment)
How is alternate gear extension achieved?
The Alternate Gear Extension Lever relieves the hydraulic pressure in the landing gear lines and releases all uplocks causing the Landing Gear to extend in freewill with the aid of gravity and aerodynamic forces
With Slats/Flaps in the Landing Position (5 or Full) the LANDING GEAR Aural Warning will sound and CANNOT be silenced when:
Regardless of the thrust lever position & RAD ALT
With NO Slats/Flaps the LANDING GEAR Aural Warning will sound and CANNOT be silenced when:
RAD ALT below 700ft AGL
AND
2 Engines - either Thrust Lever set below 45°
OEI - Thrust Lever set below 60°
When would the Landing Gear Warning Inhibit Button inhibit the Landing Gear Aural Warning, and what would indicate that it has been pushed?
Dual Rad Alt Failure
Slats/Flaps: Clean - Flaps 4
White Striped Bar would illuminate
When would the White Bar on the Landing Gear Warning Inhib Button Extinguish?
2 Engines - either Thrust Lever set below 45°
OEI - Thrust Lever set below 60°
OR
Slats/Flaps 5 or FULL without Landing Gear DOWN & LOCKED
Why must the Emergency brake be pulled slowly and carefully if used in the event of normal brake failure?
Emer/Parking Brake does not have Antiskid Protection
How does Autobrake Work?
Modulates hydraulic pressure to the brakes to provide a constant deceleration rate
What EICAS label indicates Autobrake is ARMED
WHITE A-BRK, followed by the mode in GREEN
What does a WHITE UP label in WHITE BOX indicate?
Respective Landing Gear is UP and LOCKED
What does an AMBER Cross-hatched Box indicate?
The Respective Landing gear is in transit
How long after selecting the gear down would you receive a disagreement indication if one leg did not lock down?
20 seconds
What does a RED DN/UP in a RED CIRCLE/BOX indicate?
Discrepancy between landing gear lever position and the landing gear
When does the Emer/Parking brake Indicator Illuminate ON?
When the brake is actuated and there is hydraulic pressure in the brake line
What does an AMBER accumulator pressure indication mean?
Brake Effectiveness degraded