the learning never stops!

Landing Gear and Brakes

G500 Systems

Up until now, the landing gear system on Gulfstreams could have been designed by Rube Goldberg; they had lots of parts that somehow worked together to produce a reliable result. The gear usually came up when you wanted it to, and it almost always came down. But it was complicated and took a lot of care and feeding. My initial impression of the G500 system is a lot of the cranks and levers have been replaced by a computer. There are far fewer parts and that means it weighs less and should be even more reliable. Should. We'll see.

Work in progress



How it works . . .


Normal Landing Gear Extension and Retraction

Landing Gear Retract Sequencing

Work in progress

Landing Gear Extend Sequencing

Work in progress

Normal Wheel Brakes

The wheel brakes are fairly conventional for a "brake-by-wire" system:

Normal brake application

Work in progress

Touchdown Protection

Work in progress

Antiskid Protection

Work in progress

Normal Nose Wheel Steering

Operation

Work in progress

Warming Mode

Work in progress

Active Mode

Work in progress

Deactivated (Shimmy Damping) Mode

Work in progress


The components in greater detail . . .


Anti-Skid System

[PAS, p. 10-26] Anti-Skid System

  • Designed to safely minimize stopping distance

  • Modulates hydraulic pressure to 4 main wheel brakes when skid detected; each wheel brake assembly individually controlled, compares each wheel deceleration to ideal reference deceleration; if wheel deceleration rate > ideal deceleration rate, a skid is detected. In this case BCU directs BCV to modulate brake press to stop skid. If a WST fails, that brake receives 25% less brake pressure than adjacent wheel on the same strut.

  • No anti-skid protection < 10 kts

  • Additional Anti-Skid System protections: Touchdown Protection, Locked Wheel Protection, Controlled Wheel Spin Down

Touchdown Protection

  • Ensures brake pressure not applied prior to touchdown

  • Zero brake press applied until wheel speed > 70 knots or 5 seconds after WOW = GND mode if wheel speed < 30 kts

  • Provided when following conditions met: aircraft in air mode, landing gear down / locked, and wheel speed < 70 kts

Locked Wheel Protection

  • BCU uses wheel speed transducer information to determine reference velocity for specified wheel pairs; Reference velocity defined as higher of 2 wheel speeds when compared inboard to inboard and outboard to outboard.

  • Locked wheel condition: given wheel drops to < 30% of pairs reference velocity

  • When locked wheel indication is detected, brake pressure is modulated until speed recovers

Controlled Wheel Spin Down

    Brake press applied during gear retraction / extension

  • During retraction → Controls rate of wheel spin down. Activates when following conditions met: WOW = Air mode, Gear handle UP, Airspeed ≥ 100 KCAS. When activated, 500 to 800 psi brake pressure applied for 4.5 secs, then normal antiskid protection resumes. If wheel spinning continues 15 seconds after start of retraction, you get a Wheel Despin Fail CAS message.

  • During extension → Checks system health by applying about 1500 psi brake pressure for 4 seconds. (Confirms valve operation.)

Autobrakes

[PAS, p. 10-27] Autobrakes

  • Arming Modes are selected via TSC 1-4

    • Off → Not armed (Power up default)

    • RTO → Rejected Takeoff

    • Low

    • Medium

    • High

  • Takeoff. If RTO armed during takeoff, system is enabled at 60 knots wheel speed, activates when throttles reduced to idle. If wheel speed is between 60 and 80 knots, ramps up brake pressure over 1 second to 600 psi. If wheel speed greater than 80 knots, system activates full anti-skid braking.

  • Landing. Initial brake application assists in de-rotation. Deceleration braking ramps in over 3 seconds and provides three rates of deceleration:

    • Low → 7’ / sec²

    • Medium → 10’ / sec²

    • High → Anti-Skid limit provided NLG WOW

  • System disengages when:

    • selected off

    • brake pedal deflection > 25% for 1 second

    • brake pedal deflection > 25% then < 8%

    • brake pressure > AB commanded pressure

    • throttles advanced above idle.

  • If autobrakes are allowed to continue to a full stop, auto system maintains max brake pressure after stopping.

images

Photo: G500 Autobrakes, PAS, p. 10-40

Click photo for a larger image

[PAS, p. 10-40]

  • TSCs 1 – 4

  • POF → Takeoff → Autobrake: Off (Default) or RTO

  • POF → Arrival → Autobrake: Grayed out until gear down, Selections available once gear down: Off, Low, Medium, High

  • Autobrake selection on Perf Landing → AC Cfg page; for performance calculations only, actual AB selection for landing accomplished via POF → Arrival

Autobrakes Performance

I heard early on that autobrakes "HIGH" produce results equal to charted braking distance, "MEDIUM" produces 1.57 times the distance, and "LOW" produces 2 times the distance. This does not appear to be true if you look at the landing distance chart. It appears "HIGH" is actually better than the charts and the lower settings do have added factors but those factors are not constant.

images

Photo: G500 Autobrake landing distance adjustments, AFM, EXTRACT, §05-11-00, fig. 8

Click photo for a larger image

Axle Information Module (AIM) / Wheel Speed Transducers (WSTs)

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Photo: G500 Brakes, PAS, p. 10-23

Click photo for a larger image

Work in progress

Brake Accumulators

images

Photo: G500 Brake accumulators, PAS, p. 10-25

Click photo for a larger image

[PAS, p. 10-25] Brake Accumulators (2)

  • Inboard and Outboard

  • Located aft of main wheel well, covered by access panel

  • Store hydraulic energy for parking and emergency brake application. Inboard energy recharged by Left System, PTU, or Aux System. Outboard energy recharged by Right System

  • Pressure is retained in each accumulator until actuated by PARKING BRAKE handle or toe brakes if normal hydraulic press not available

  • Accumulator pressure drops when used, eventually to nitrogen pre-charge pressure of 700 psi @ 70°F

  • Press displayed in cockpit via brakes 1/6 synoptic page

  • Nitrogen filler valves and direct reading pressure gauges located on aft bulkhead of each main wheel well; left wheel well for the inboard accumulator, right wheel well for the outboard accumulator.

  • Operational considerations for emergency braking

    • Each application bleeds down accum press

    • One continuous application is recommended: use full toe brake displacement for full anti-skid application, or pull PARKING BRAKE Handle to a target of 600 psi using the Brakes 1/6 synoptic page, anti-skid will not be available.

    • Do not continue taxiing after coming to a stop

Brake Assemblies

images

Photo: G500 Brakes, PAS, p. 10-21

Click photo for a larger image

[PAS, p. 10-21]

  • 2 Brake assemblies per main landing gear (1 on each wheel): inboard and outboard

  • Each brake assembly functions as normal toe brakes, parking brakes, and provides main wheel de-spin during retraction of gear.

  • Each brake assembly features a carbon heat stack (lighter weight and higher performance than steel).

  • Hydraulically powered inboards (Left System, PTU, Aux System) and outboards (Right System)

  • Brake-by-Wire System with pilot inputs via toe brakes.

  • Anti-skid available via toe brakes with hydraulic or accumulator pressure but is not available via PARKING BRAKE handle.

  • Brakes not installed on nose gear.

Brake Control Unit (BCU)

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Photo: G500 Brake Control Unit, PAS, p. 10-22

Click photo for a larger image

[PAS, p. 10-22] Brake Control Unit (BCU)

  • Digital microprocessor that controls Brake-by-Wire System (Located in LEER)

  • 2 independent channels, one for inboard brakes, one for outboard brakes; failure of one does not affect the other

  • Provides: Brake-by-Wire application, Individual wheel brake control, Anti-skid functions, Autobraking, DCN communication, Continuous BIT testing, Brake Temperature Monitor System (BTMS) processing, Wheel speed transducer interface, Shutoff valve control, Brake pedal signal conversion (based on pedal deflection), Wheel De-Spin, and Wheel spin-up signal

Brake Control Valves (BCVs)

Work in progress

Brake Pedals

Work in progress

Brake Pressure Transducers

Work in progress

Brake Shutoff Valves (SOVs)

Work in progress

Brake Shuttle Valves

Work in progress

Brake Synoptics

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Photo: G500 Brakes synoptics, PAS, p. 10-44

Click photo for a larger image

[PAS, p. 10-44]

  • Applied brake pressures appear as 4 bar graphs separated by pressure scale is psi: Normal → 0 – 3000, BBW Fail → 0 – 800, and a yellow line at 600 serves as a reference line for stopping with parking brake.

  • Accumulator pressures (psi) reflect a full charge at 3000 psi.

  • AutoBrake selection display: RTO, OFF, LOW, MED, and HIGH.

  • BTMS brake temperatures are 4 bar graphs separated by a temperature scale from 0 - 600°C.

  • Peak Temp display assists with brake cool down time determination if required prior to next takeoff

Brake Temperature Monitoring System (BTMS)

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Photo: G500 BTMS, PAS, p. 10-24

Click photo for a larger image

[PAS, p. 10-24] Brake Temperature Monitoring System (BTMS)

  • BTMS probes (4): 1 in each main wheel brake assembly, sensor tip near center of brake heat stack.

  • Brake temp info sent to BCU, Cockpit displays (brake 1/6 Synoptic and CAS)

Downlocks

Work in progress

Downlock Safety Pins

images

Photo: G500 Gear pins, PAS, p.10-6

Click photo for a larger image

[PAS, p. 10-6] Downlock Safety Pins:

  • Designed to withstand full hydraulic retraction pressure. Gear will not retract on takeoff if pin left in.

  • Main Gear (2): located at lower end of each sidebrace actuator, prevents internal downlock of actuator from unlocking.

  • Nose Gear (1): located on Folding Truss Brace near top of nose gear strut, prevents movement of Nose Gear Downlock Actuator and Overcenter Linkage.

  • Remove during Exterior Preflight Inspection

Emergency Extension System

images

Photo: G500 Emergency gear extension system, PAS, p. 10-16

Click photo for a larger image

[PAS, p. 10-16]

  • 2 Nitrogen bottles, located on each side of nose wheel well. Service pressure of 3,000 psi at 70°F / 21°C is enough for one extension.

  • EMER LDG GEAR handle located on pilot side of forward skirt panel designed for easy reach by either pilot. Pulling the handle fully outward activates Landing Gear Emergency Extension System.

  • Dump Valves (2) — 1 for mains and 1 for nose — allows nitrogen into landing gear system, isolates nitrogen from other portions of the hydraulic system. Reset switches located on OHPTS → Hyd / CPCS page (a maintenance function).

images

Photo: G500 Landing gear emergency extension sequence, PAS, p. 10-17

Click photo for a larger image

[PAS, p. 10-17]

  • Airspeed ≤ 175 KCAS

  • Landing Gear Handle → Down allows for proper gear indications to occur once extended and will cause white light in handle to illuminate.

  • EMER LDG GEAR Handle → Pull fully outward

    • Nitrogen released into Landing Gear Extension System and pneumatic pressure actuates Dump Valve portion of Landing Gear Selector / Dump Valves. Dump Valve switches on OHPTS → Cyan indication. Landing Gear System is isolated from the hydraulic system and pneumatic pressure routed to OPEN side of gear door actuators (doors open), UNLOCK side of gear uplock actuators (gear uplocks unlock), and EXTEND side of main gear sidebrace actuators and nose gear extend / retract actuator.

    • Gear extends in approximately 6 seconds. Check for white light in handle to extinguish and three green (L, N, R). Gear doors remain open

images

Photo: G500 Resetting EMER LDG GEAR Handle and Dump Valves, PAS, p. 10-18

Click photo for a larger image

[PAS, p. 10-18] Resetting EMER LDG GEAR Handle and Dump Valves:

  • When handle is returned to stowed position, pneumatic pressure releases from actuators and nitrogen vents overboard in about 30 seconds.

  • Dump Valves reset via switches on OHPTS, electrical solenoid moves Dump Valves to normal position and returns hydraulic system access to landing gear system. Once reset the dump valve switches indicate white nose and main gear.

Gear Doors

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Photo: G500 Gear doors, PAS, p. 10-13

Click photo for a larger image

[PAS, p. 10-13]

  • Hydraulically operated doors; Left, PTU and Aux; Opened and closed with door actuators; Remain closed except during gear extension / retraction; 2 Main inboard doors, 2 Nose gear doors.

  • Fairing doors; Mechanically attached to struts; 2 Main, 1 Nose; Open and close with gear

Hydraulic Fuses

Work in progress

Landing Gear Control Handle

images

Photo: G500 Landing gear control panel, PAS, p. 10-34

Click photo for a larger image

[PAS, p. 10-34] Landing Gear Control Handle (Gear Handle)

  • Used to select gear UP or DOWN during normal ops. Must move to left prior to moving up or down.

  • Gear handle DOWN position also allows nose wheel steering, anti-skid braking, and correct gear position indications after emergency extension (but has no effect on operation of emergency extension system).

  • White light in handle indicates a disagreement between position of handle and gear. With handle UP remains on until all gear are up and locked. With handle DOWN remains on until all gear are down and locked.

  • Landing gear indication Lights are located above gear handle, arranged on panel to represent actual gear positions on aircraft. L → Left Main, N → Nose, R → Right Main

  • GREEN when associated gear down and locked, extinguishes when associated gear unlocks

  • Indications same whether using normal or emergency system.

  • If difference between LGCP indications and Flight Controls synoptic, the LGCP indications take precedence.

[PAS, p. 10-35] LOCK RELEASE Button

  • Electromechanical lock prevents gear handle from being raised if button extended outward from panel, happens when landing gear down and WOW in ground mode.

  • Depressing button allows gear handle in UP position regardless of WOW mode.

  • With WOW in air Mode, button flush with panel surface and lock disengaged.

[PAS, p. 10-35] Total DCN Failure or Dual RDC 15 and 17 Failure

  • Normal landing gear control still available

  • All landing gear indications unavailable

Landing Gear Control Maintenance Panel (LGCMP)

images

Photo: G500 Landing Gear Control Maintenance Panel, PAS, p. 10-49

Click photo for a larger image

[PAS, p. 10-49]

  • Used to open / close gear doors, not required during normal Exterior Preflight Inspection, required for Exterior Preflight Inspection (Expanded).

  • Maintenance only functions: extend / retract gear, WOW override

  • LG Mode switch (2 position momentary switch):

    • NORMAL. Deactivates all other switches on the panel, spring-loaded to this position.

    • MAINT. Allows activation of all other panel switches, landing Gear Handle inputs ignored.

    • Landing gear system always considers true WOW regardless of LG Mode switch position to prevents gear retraction when not on jacks.

Landing Gear Control Manifolds (LGCM)

Work in progress

Landing Gear Control Unit (LGCU)

[PAS, p. 10-3]

  • Controls electrical sequencing and operation of landing gear and gear doors

  • Uses inputs from: landing gear handle, proximity sensors, and WOW data.

  • Components of each separate landing gear operate in unison and independently of other landing gear.

Landing Gear Warning Horn

images

Photo: G500 Landing gear warning horn, PAS, p. 10-20

Click photo for a larger image

[PAS, p. 10-20] Landing Gear Warning Horn:

  • Klaxon tone activated when

    • Flap handle selected > 22° and any gear not down and locked

    • Flap handle selected < 22° and < 345’ AGL and throttle near idle (< 5° RVDT angle) and any gear not down and locked

    • CWOW ≠ AIR and gear handle selected UP

  • Ldg Gear Horn Inhibit

    • Soft guarded switch

    • TSCs 1-4 → Menu → Aural Inhibits

    • Grayed out until gear horn activated

    • When selected, LG Horn Audio Inhibited, silences gear warning horn ≥ 345’ AGL. Gear horn overrides inhibit < 345’ AGL

    • Resets to gray when conditions for gear aural warning horn no longer valid or < 345’ AGL.

Nose Landing Gear Components

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Photo: G500 Nose landing gear, PAS, p.10-7

Click photo for a larger image

[PAS, p. 10-7] Components

  • Single stage nitrogen and oil-filled shock strut absorbs shock of taxi, takeoff and landing. It is a steel piston riding in a cylinder, utilizes ring seals to prevent leakage of nitrogen-oil.

  • Nose Wheel Steering System.

  • Taxi lights (LED).

  • Hydraulic lines.

  • Wiring harnesses.

  • 2 Nose wheels. Tires are designed with a chine to deflect water to prevents excessive water ingestion into engines, rated to 195 kts, good for approximately 220 landings. Safety plugs opens and deflates tire if internal pressure > about 375 psi.

  • Tie down rings.

  • Jack pad.

  • Attachment point for towing.

Nose Wheel Steering System

images

Photo: G500 Nose wheel steering system, PAS, p.10-9

Click photo for a larger image

[PAS, pp. 10-8 to 10-9] Nose Wheel Steering system:

  • Electro-hydraulic steer-by-wire system is electronically controlled, hydraulically powered, and mechanically actuated by input from rudder pedals or tiller.

  • Interfaces with DCN. Built-in test and failure reporting. Ground speed determination. Flight phase determination.

  • Speed sensitive range of motion: maximum steering angle decreases as ground speed increases.

  • Nose Wheel Steering Control Unit (NWSCU)

    • Provides steer-by-wire control inputs to Nose Wheel Steering Unit (NWSU)

    • Receives control inputs measured by RVDTs from rudder pedals via FCCs and tiller.

    • Receives position feedback inputs from RVDTs on NWSU (Primary) and Steering Collar (Secondary)

  • Nose Wheel Steering Unit (NWSU)

    • Converts hyd press into torque to rotate nose wheels

    • Connected to Steering Collar (transfers torque to torque links)

    • Contains 2 Hydraulic Solenoid Operated Valves (SOVs); SOV #1 opens upon gear extension (provides hyd fluid through orifice to warm NWSU), SOV #2 opens after landing / Nose WOW Gnd Mode + 1 sec (provides control hydraulics to Electro-Hyd Servo Valve to meters hydraulic to motor portion of NWSU)

    • Provides damping even when NWSS deactivated via trapped hydraulic fluid; damping also by mechanical gearing of steering collar.

images

Photo: G500 Nose wheel steering components, PAS, p.10-10

Click photo for a larger image

[PAS, p. 10-10]

  • Torque Links (2) link NWSU torque from Steering Collar to NLG axle which rotates nose wheels. The upper is connected to NWS Collar by quick-release pin, the lower connects to NLG axle.

  • An over-travel Indicator operates and latches when NWSU forced beyond powered range. If steering unit exceeds 84° of travel → Indicator pops out. White and flush is normal, red and extended means maintenance inspection is required. A stop pin sits at 86° and can be sheared if excessive force applied. A proximity switch activates if the over-travel Indicator pops and triggers NWS Maintenance Required CAS message.

images

Photo: G500 Nose wheel steering operation, PAS, p.10-12

Click photo for a larger image

[PAS, pp. 10-11 to 10-12] Operation

  • Closely monitored / controlled by NWSCU

  • NWSS POWER switch

    • Located next to Tiller on left side console

    • Guarded switch

    • ON: provides hydraulics to NWSU, enables tiller steering

    • OFF: disables tiller steering, disables rudder pedal steering; nose wheel free to castor

  • PEDAL STEERING switch

    • Located to right of NWSS POWER switch

    • Guarded switch

    • ON → Enables rudder pedal steering; NWSS POWER must also be selected ON; FCCs send pedal inputs to NWSCU

    • OFF → Disables rudder pedal steering

    • Pedal steering authority → +/- 40°; Min taxi strip for 180° turn is 125’

    • Pedal steering is normally all that’s needed for normal ground ops

  • Tiller

    • Steering authority → +/- 82° (tiller and pedal inputs are additive but never exceed +/- 82°); Min taxi strip for 180° turn: 60’

    • Use as needed for very tight turn radius situations

    • Landing checklist CAUTION: limit use of tiller to speeds < 30 kts

  • Speed sensitive steering

    • Pedals and tiller

    • Maximum steering angle decreases as ground speed increases

    • If ground speed data not valid → Fixed Gain Mode: pedal steering → +/- 7°, tiller steering → +/- 82°. NWS usually requires only normal pedal inputs during landing rollout and normal taxi speeds. At slow taxi speeds → Tiller may be required for adequate control

  • Towing

    • Procedures located in AOM, HANDLING AND SERVICING PROCEDURES, 06-03-70, Nose Landing Gear Towing

    • Disconnect nose wheel TPMS prior to disconnecting torque link; when reinstalling TPMS, tighten so red line not visible for proper connection.

    • Disconnect upper torque link prior to towing to allows nose wheel 360° travel and prevent over-travel damage to NWSU.

    • If torque link connected and NWS system ON, ECM recognizes power-on towing attempt and shuts down NWSS to allows nose wheel to free castor.

Parking Brake System

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Photo: G500 Parking brake system, PAS, p. 10-26

Click photo for a larger image

[PAS, p. 10-26]

  • Mechanical → Not brake-by-wire

  • Power source → Accumulator pressure only. With the PARKING BRAKE handle fully up, all available inboard / outboard accumulator pressure applied to all four brake assemblies. To release from locked position, depressurize PUSH TO DISENGAGE button on top of handle.

  • Repeater valve ensures outboard accumulator pressure applied equal to or slightly less than inboard accumulator pressure, allows for even braking when using parking brake handle. Inboard accumulator pressure is controlling pressure, for example if inboard pressure = 0 and outboard pressure = 3000, total available with parking brake = 0.

  • Parking Brake is not designed to hold aircraft for extended periods; always chock aircraft.

Pedal Position Transducer (PPT)

Work in progress

Proximity Sensors

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Photo: G500 Proximity sensors, PAS, p. 10-3

Click photo for a larger image

[PAS, p. 10-3]

  • Interfaces: Landing gear position, landing gear door position, Weight-On-Wheels (WOW) indication.

  • Use magnetic signal to indicate position or status of each: landing gear, landing gear door, WOW sensor.

  • Each reports its position to LGCU for proper gear sequencing.

Repeater Valve

The left brake accumulator receives pressure from the left hydraulic system as well as the Aux pump; the right accumulator only from the right system. In the even you are using the parking brake to stop the airplane, the designers want to make sure the outboard pressure cannot exceed the inboard pressure. I'm not sure why this is important, but it allows us to use the parking brake handle while focusing on the inboard brakes.

[PAS, p. 10-26]

  • Repeater valve ensures outboard accumulator pressure applied equal to or slightly less than inboard accumulator pressure, allows for even braking when using parking brake handle. Inboard accumulator pressure is controlling pressure, for example if inboard pressure = 0 and outboard pressure = 3000, total available with parking brake = 0.

Uplocks

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Photo: G500 Gear uplocks ready to receive, PAS, p. 10-5

Click photo for a larger image

[PAS, p. 10-5] Uplocks:

  • One per gear assembly: Main Gear (2), Nose Gear (1)

  • Purpose is to retain gear in mechanically locked position in flight within gear bays by use of uplock latch that captures uplock roller on gear. The uplocks move into “ready to receive” position after gear extension. If found in wrong position on preflight, will snap into correct position when hydraulic pressure is applied. During retraction, gear retract actuators deliver gear uplock rollers into uplock latches. As roller engages into latch, uplock springs assist latch to rotate, pushes lock links over-center and securely locks latch assembly.

  • Check for general integrity during preflight inspection.

Weight on Wheels (WOW) System

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Photo: G500 Landing gear Wow - Near (Air Mode), PAS, p. 10-4

Click photo for a larger image

[PAS, p. 10-4]

  • 2 Proximity sensors installed on each landing gear.

  • Provides WOW AIR or GROUND mode status to various aircraft systems / components; may operate differently depending upon aircraft being inflight or on ground.

  • Strut extended → Air Mode. Target moves close to proximity sensor (Target Near), a magnetic pickup detects the target.

  • Strut compressed → Ground Mode. Target moves away from proximity sensor (Target Far), a magnetic pickup unable to detect target.

images

Photo: G500 Landing Gear Control Maintenance Panel, WOW OVRD switch, PAS, p.10-4

Click photo for a larger image

[PAS, p. 10-4]

  • WOW OVRD switch: Landing Gear Control Maintenance Panel (LGCMP), maintenance use only, allows aircraft to be in Air Mode on ground.

images

Photo: G500 Flight controls synoptic, PAS, p. 10-42

Click photo for a larger image

[PAS, p. 10-42]

  • WOW status (Air or Ground) for: Left Main Gear, Nose Gear, Right Main Gear, Combined WOW

  • Combined WOW is a combination of L and R Main Gear WOW signals provided to various aircraft systems, such as: NWS, EDS, EICAS, BAC, CPCS, CVR, TCAS, etc.

  • In case of a miscompare, system looks first to corresponding proximity sensor from other control lane. If both lanes fail, system looks to safest condition such as NWS → Damped castor mode.

  • Gear and WOW status not displayed when gear stowed.

Wheels and Tires

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Photo: G500 Wheels, PAS, p. 10-32

Click photo for a larger image

[PAS, p. 10-32]

  • Wheels, 2 per Main, conventional hub and flange arrangement, hub covers wheel speed transducers

  • Fusible Thermal Release Plugs (4), 1 inside each wheel, designed to melt at 415°F due to hot brakes, releases air pressure from tires to prevent tires from exploding under pressure

  • Over-inflation Safety Plug (1) installed in each wheel, designed to deflate at approx 515 psi

  • Retaining ring ensures security and integrity of wheel / tire assembly. Preflight: check flush, secure and undamaged

  • Tires: Speed-rating → 195 kts, designed for approximately 220 landings. Preflight: check condition, inflation, tread wear and cuts

Tire Pressure Monitoring System (TPMS)

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Photo: G500 TPMS, PAS, p. 10-33

Click photo for a larger image

[PAS, p. 10-33]

  • Monitors tire pressures for all six tires and alerts crew of improper tire pressure with Tire Pressure Low or Tire Pressure Low

  • Tire Pressure Monitoring Unit (TPMU) is the main processing unit for TPMS, located in REER, receives tire press data from all 6 tires, transmits data for display in cockpit TSCs 1-5, Ground Service 1/6 synoptic, and CAS messages. Auto records tire pressures for each flight.

  • TPMS cable on nose wheel must be removed prior to disconnecting torque links. When reconnecting → Red line must not show. Cockpit indications dash out if not connected properly.

  • You can dispatch without this system IAW MEL

images

Photo: G500 Tire pressure synoptic, PAS, p. 10-43

Click photo for a larger image

[PAS, p. 10-43]

  • Tire pressure is always displayed on ground service 1/6 synoptic pages.


Limitations and Abnormal Procedures


Limitations

AFM, §01-03-30

  • Maximum Operating Altitude for For Extension/Flight Landing Gear Extended: 20,000 feet.

  • Maximum Landing Gear Extended Speed (VLE): 250 KCAS.

  • Maximum Landing Gear Operation Speed (VLO): 225 KCAS.

  • Emergency Landing Gear Extension Limit Speed: 175 KCAS.

  • Maximum speed with the landing gear extended utilizing the alternate system: 225 KCAS.

AFM, §01-32-10

  • Tire Pressure: Recommended tire pressure for all takeoff gross weights is 182 PSI for nosewheel tires and 223 PSI for main wheel tires, when tires have been stationary for at least 2 hours.

References

Gulfstream GVII-G500 Airplane Flight Manual, Revision 1, August 31, 2018

Gulfstream GVII-G500 Production Aircraft Systems, Revision 1, Oct 1, 2018

Revision: 20190529
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