Gulfstream G650ER Elevator Hydraulic Actuation PDF

GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL ELEVATOR HYDRAULIC ACTUATION — SYSTEM DESCRIPTION 1. General A. Description The elevator hydraulic actuators are powered by 3000 psi from the left and right hydraulic systems during normal operation. Hydraulic system pressure is ported from the elevator ma...

GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL ELEVATOR HYDRAULIC ACTUATION — SYSTEM DESCRIPTION 1. General A. Description The elevator hydraulic actuators are powered by 3000 psi from the left and right hydraulic systems during normal operation. Hydraulic system pressure is ported from the elevator manifolds to the elevator actuators to drive the elevator to its commanded location. See Figure 1 and Figure 2. Hydraulic actuation is commanded by the Flight Control Computers (FCCs) or Backup Flight Control Unit (BFCU). The FCCs provide position signals to the Remote Electronic Units (REUs) and Motor Control Electronics (MCE) using Bidirectional ARINC 429 (BD429) digital data buses. The REUs process the signals to drive hydraulic manifold valves that initiate actuator movement to control the flight surface movement. If both FCCs fail, the BFCU provides position signals to the REUs using standard ARINC 429 (A429) digital data buses. The following three types of manifolds drive the actuators: EB HA EHSA The following two types of actuator systems are used, both operate in active / active state: EHSA system EBHA system The EHSA system includes a hydraulic cylinder / piston assembly and a separate manifold. The EBHA system includes a hydraulic EHSA type part, mated with a local MCE controlled Integrated Motor Pump Assembly (IMPA) that drives the hydraulic cylinder / piston in electric backup state. The backup state is used if the aircraft hydraulic system fails and the adjacent EHSA is unavailable. NOTE: Hydraulic manifolds for EHSA type and EBHA type spoiler actuators are not interchangeable. The same REU fits all locations. The applicable REU software is selected by installation strapping for each location. The actuation system may operate in one of the following six states, depending on the possible system failures that may occur: TYPE OF CONTROL REU STATE DESCRIPTION Dual hydraulic EBHA active hydraulic state and EHSA active, both controlled by their REU; force fight alleviation in EBHA REU using EHSA pressure sensors. EHSA only EHSA in hydraulic state controlled by its REU, EBHA (inop) in damped bypass state. EBHA only EBHA active in hydraulic state controlled by its REU, EHSA (inop) in damped bypass state. EBHA electrical backup EBHA in electric state controlled by its REU / MCE, EHSA (inop) in damped bypass state. 27-33-00 Page 1 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL TYPE OF CONTROL STATE DESCRIPTION MCE MCE backup position control EBHA active in electric state is controlled by the MCE backup controller function, EHSA is in damped bypass state. No control Damped bypass EBHA and EHSA in damped bypass state (no REU / MCE control). 2. Component Location COMPONENT ATA QTY PER A/C LOCATION Elevator EHSA Actuator 27-33-01 2 Horizontal stabilizer rear beam Elevator EBHA Actuator 27-33-03 2 Horizontal stabilizer rear beam Elevator EHSA Manifold 27-33-05 2 Horizontal stabilizer rear beam Elevator EB Manifold 27-33-07 2 Horizontal stabilizer rear beam Elevator HA Manifold 27-33-09 2 Horizontal stabilizer rear beam 3. Component Details A. Elevator EHSA Actuator The elevator EHSA hydraulic actuator is a flange-mounted actuator that employs a toggle link to ensure freedom of motion while providing the hinge moment required to deflect the elevator during pitch functions. The actuator accepts hydraulic inputs from the adjacent elevator EHSA manifold and provides positional feedback to the elevator REU via a single channel main ram LVDT to close the control loop during all states of operation. Left and right outboard actuators are EHSAs. An EHSA is controlled electrically by its REU and uses hydraulic power to move the control surface. The left EHSA REU receives electrical power from a single circuit breaker on the left essential dc bus. The right EHSA REU receives electrical power from a single circuit breaker on the right essential dc bus. The EHSA system consists of the following three components: REU Hydraulic actuator Hydraulic manifold Independent surface LVDT The left actuator is separate from the REU and receives hydraulic power from the aircraft left system. The right actuator is separate from the REU receives hydraulic power from the aircraft right system. The elevator control surfaces have additional LVDT sensors that provide surface position to the REU required for the mitigation of the actuator ram LVDT disconnect failure mode. There are no other electrical components in the actuator. The EHSA (outboard actuator) has the following two states of operation: Active hydraulic (normal) Damped bypass (1) Active Hydraulic State 27-33-00 Page 2 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL In the EHSA active hydraulic state, the Mode Select Valve (MSV) is energized and allows hydraulic flow from the Electro-Hydraulic Servo Valve (EHSV) to the actuator. In the active hydraulic state, the REU energizes a normally open three-way MSV Solenoid Operated Valve (SOV) that moves the MSV into the active position. The active position connects the cylinder ports to the EHSV and disconnects the cylinder ports from the Variable Damping Orifice (VDO). In EHSA active hydraulic state, the REU uses the internal main ram LVDT signal to determine the main ram position and then calculates the difference between the commanded ram position (from the FCC or the BFCU) and the actual ram position to generate an error signal. The REU applies an electrical command current to the first stage coils in the EHSV that is proportional to the error signal. The EHSV command current proportionally increases the flow orifice metering area between supply pressure and one cylinder port along with the flow orifice metering area between return pressure and the opposing cylinder port. The polarity of the EHSV command current causes the ram to move in a direction that reduces the positional error signal until the error signal reaches zero. The polarity of the EHSV command current in effect determines which cylinder ports (extend or retract) get connected to supply and return pressures. (2) Damped Bypass State The EHSA system is placed in damped bypass state when the MSV is de-energized. The state is entered when there has been a failure in the REU or the aircraft hydraulic system. A damping force is placed on the actuator since it is no longer being actively controlled, but still needs to provide sufficient damping for flutter suppression. The associated EBHA actuator, is also actively controlling the same surface and will overcome the damping force of the EHSA actuator. In the EHSA damped bypass state, the actuator may be commanded to shut down through a solenoid valve driving the MSV. The REU de-energizes the three-way MSV SOV that moves the MSV so that the cylinder ports are disconnected from the EHSV and interconnected through the VDO. Upon loss of electrical or hydraulic power the actuator MSV automatically reverts to the damped state. B. Elevator EBHA Actuator The elevator EBHA hydraulic actuator is a flange-mounted actuator that employs a toggle link to ensure freedom of motion while providing the hinge moment required to deflect the elevator during pitch functions. The actuator accepts hydraulic inputs from the adjacent elevator HA manifold and provides positional feedback to the elevator REU and MCE via a dual channel main ram LVDT to close the control loop during all states of operation. The EBHA system includes a hydraulic cylinder / piston assembly and two hydraulic manifolds (HA and EB). A separate hydraulic actuator is located between the EB and HA manifolds. The hydraulic actuator contains a two channel LVDT that provides position sensing information. One channel is connected to the REU and the other to the MCE. There are no other electrical components in the actuator. The left and right inboard actuators are EBHAs. An EBHA is controlled electrically by its REU and uses hydraulic power to move the control surface. The left actuator receives hydraulic power from the aircraft right system. The right actuator receives hydraulic power from the aircraft left system. The EBHA system consists of the following five components in each wing: REU MCE Hydraulic actuator 27-33-00 Page 3 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL Electric backup manifold Hydraulic actuation manifold The left and right EBHA REUs receive electrical power from two separate circuit breakers located on the UPS bus. If both the EBHA REU and EHSA REU are invalid, the MCE has a limited capability to control the electrical motor and actuator on its own. In that condition, the MCE receives the surface command signals directly from one of the FCCs on the MCE A429 bus. The EBHA has the following three states of operation: Active hydraulic (normal) Damped bypass Electrical backup (power select valve de-engerized) (1) Active Hydraulic State In the EBHA active hydraulic state, hydraulic pressure is from the aircraft system. The EHSV modulates the flow of fluid to provide the desired actuator movement. The Power Select Valve (PSV) controls the state between normal and electrical backup. In the normal energized position, the valve allows the EHSV modulated aircraft hydraulic pressure to move the actuator. The de-energized position allows pressure from the self contained electrical backup hydraulic system to move the actuator. The EBHA active hydraulic state with normal hydraulic power provides closed-loop positional control of the EBHA, using the EHSV. When the EBHA is commanded into active state with normal hydraulic power, the REU and MCE energize a torque motor that positions the twoposition MSV into the active position. The active position connects the cylinder ports to the EHSV and disconnects the cylinder ports from the VDO. The REU and MCE also energize another torque motor that positions the two-position PSV into the position for normal hydraulic power. The PSV connects hydraulic system pressure to the EHSV and connects the EHSV extend and retract control ports to the ram via the MSV. (2) Damped Bypass State The EBHA damped bypass state provides for adequate dynamic damping (imaginary) stiffness to prevent surface flutter in the event of a loss of all hydraulic pressure or electrical power. The EBHA may be commanded into the damped bypass state or the EBHA will default to the damped bypass state, if there is a loss of electrical power or hydraulic pressure. A damping force is placed on the actuator since it is no longer being actively controlled, but still needs to provide sufficient damping for flutter suppression. The associated EHSA actuator actively controlling the same elevator will overcome the damping force of the EBHA actuator. (3) Electrical Backup State In the EBHA electrical backup state the EHSV is bypassed and the starting, stopping and reversing of the electrical pump motor modulates the flow of fluid to provide the desired actuator movement. The MSV controls entry into the damped bypass state. In the energized position the MSV allows hydraulic flow during either normal or electrical backup state. Electrical backup control of a surface is only done if both the EHSA and EBHA systems do not function in their normal hydraulic state. There will not be mixed operation where an EHSA is operated in its normal hydraulic state and the EBHA is in electrical backup state. However, the electrical pump function is activated in a warm up state when there has been a hydraulic failure to the EBHA, even when the EHSA is still functioning normally. The warm up state circulates warm hydraulic fluid through the manifold and prevents it from becoming cold soaked. This insures the EBHA is ready to immediately control the surface in the event there is a subsequent failure to the EHSA that requires the electrical backup state to be engaged. 27-33-00 Page 4 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL In the EBHA electrical backup state, backup power provides closed-loop positional control of the EBHA using the pump motor. When the EBHA is commanded into active state with electrical backup power, the REU and MCE energize a torque motor that positions the twoposition MSV into the active position. The active position connects the cylinder ports to the pump and disconnects the cylinder ports from the VDO. The REU and MCE de-energize the PSV torque motor, positioning the two-position PSV for backup hydraulic power. The PSV connects the pump extend and retract control ports to the ram via the MSV and blocks hydraulic system pressure from the EHSV. In the EBHA electrical backup state, positional control is provided by first comparing the commanded ram position to the actual ram position. The REU demodulates the main ram LVDT signal to determine the main ram position and calculates the difference between the commanded ram position and the actual ram position to generate the error signal. The REU then applies an electrical command current to the MCE, which commands the electrical motor driving the pump that is proportional (within limits) to the error signal. The pump motor command current proportionally increases (within limits) the pump motor velocity. The polarity of the pump motor command determines which cylinder ports (extend or retract) get connected to the inlet and outlet ports of the pump. For proper closed-loop control, the polarity of the pump motor command current causes the ram to move in a direction that reduces the positional error signal until the error signal reaches zero. C. Elevator EHSA Manifold The manifold servo valve is commanded by the REU and ports fluid accordingly to the extend or retract chambers of the associated actuator. The manifold output is open loop as all of the command computation is done within the REU. For maintenance purposes, the manifold contains a relief valve that may be manually driven. The REU is mounted on its associated hydraulic manifold. The REU processes FCC commands and initiates electrical commands to the MSV solenoid and the EHSV. The MSV and EHSV control the flow of hydraulic fluid that moves the actuator. The EHSA manifold includes the following components: SOV MSV VDO EHSV and position sensor Fluid pressure sensors Bidirectional Relief Valve (BDRV) Fluid filter Fluid reservoir Anticavitation check valves The REU controls the EHSV to port pressure to the cylinder. The cylinder delivers the force to move the surface. Sensors within the manifold provide status information back to the REU. These include the following sensors: EHSV position LVDT Hydraulic supply and return pressure sensors Compensator position LVDT The compensator is an LP spring-loaded accumulator that stores a small hydraulic fluid reserve. The retract and extend cylinder pressure sensors are located in the EHSA manifold, but they provide information only to the EBHA REU. The sensors monitor the hydraulic pressure on both extend and retract chambers of the hydraulic actuator. The EBHA REU monitors similar pressure 27-33-00 Page 5 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL information from the EBHA actuator and compares the two pressures to insure the two actuators are working together with no force fight issue between the two. Status information in the form of a discrete signal is passed from each REU to the other. This lets the associated REU know if the other is invalid and not actively controlling the surface. D. Elevator EB Manifold The elevator EB manifold is installed at each instance of an EBHA type elevator actuator. The EB manifold contains the following components: EHSV SOV PSV IMPA Anticavitation check valves During all states of operation, the EB manifold is commanded by its electrical interface with the MCE. During normal operation, aircraft hydraulic pressure is controlled by the EHSV to extend or retract the actuator. During electrical backup states, the motor pump assembly generates hydraulic pressure to extend or retract the actuator based on the direction of motor rotation. The REU processes FCC signals and initiates electrical commands to the PSV solenoid and EHSV in the EB manifold. Those components control the flow of hydraulic fluid that moves the actuator. Sensors within the manifold provide status information back to the REU. The EB manifold contains the following sensors: EHSV position LVDT Hydraulic supply and return pressure sensors Hydraulic temperature sensor The MCE is mounted directly to the EB manifold. Each MCE has its own 65 amp circuit breaker on the 28 Vdc EBHA bus. The MCE uses the power for its internal electronics and to power the IMPA. The MCE controls the operation of the IMPA. It receives motor position and velocity information from the motor resolver. The MCE knows the status of both the EBHA REU and the EHSA REU and receives a status discrete from each. If the EBHA REU is active and the EHSA REU is inactive, the EBHA REU issues the motor velocity commands to the MCE over the REU to MCE RS485 data bus. This data bus is referred to as the Motor Control Data Link (MCDL). The MCE passes its internal status monitors back to the REU using the MCDL. E. Elevator HA Manifold The elevator HA manifold contains the following components: SOV MSV VDO BDRV Anticavitation check valves Compensator Compensator position LVDT Retract and extend cylinder pressure sensors Return relief valve NOTE: The pressure sensors monitor hydraulic pressure on both sides of the hydraulic actuator. The REU is mounted directly to the HA manifold. The HA manifold receives electrical input from the REU. The REU processes FCC signals and initiates electrical commands to the MSV solenoid in the HA manifold. This controls the flow of hydraulic fluid that moves the actuator. 27-33-00 Page 6 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL The BDRV interconnects the extend and retract chambers when the greater of the two chambers exceeds the compensator circuit pressure by more than a preset value. The BDRV limits the maximum load on the actuator, in addition to the maximum pressure in each chamber. The HA manifold interfaces hydraulically with the EB manifold to pressurize the extend / retract ports of the elevator actuator. The HA manifold features a manual override for the return relief valve. This allows maintenance personnel to move the elevator surface when required. 4. Controls and Indications A. Circuit Breakers The system is protected by the following circuit breakers: NOMENCLATURE PANEL LOCATION POWER SOURCE L ELEV HA LEER A8 L ESS 28VDC L ELEV EBHA PRI REER B3 UPS 28VDC R ELEV EBHA PRI REER B4 UPS 28VDC L ELEV EBHA SEC REER B8 UPS 28VDC R ELEV HA REER B8 R ESS 28VDC R ELEV EBHA SEC REER C8 UPS 28VDC L ELEV EBHA PWR N/A EBHA PDB (tail compartment) EBHA BUS 28VDC R ELEV EBHA PWR N/A EBHA PDB (tail compartment) EBHA BUS 28VDC B. CAS Messages The CAS messages for the system are shown in the following table: MESSAGE COLOR MESSAGE DESCRIPTION Stall Reference Speed Increase Blue Stall protection speed increased because of wing anti-ice fail and possible ice accretion on wings. Verify increased landing reference speed and increased landing distance. AP Trim Fail Blue AP trim has failed. AP Inhibit-Stall Blue AP inhibit-stall is active. Pitch Trim Nose Down Limit Blue Pitch trim at nose down limit. Adjust pitch trim as necessary. Pitch Trim Nose Up Limit Blue Pitch trim at nose up limit. Adjust pitch trim as necessary. Stick Shaker 1-2 Fail Blue Stick shaker 1 and 2 have failed. AP Inhibit-Manual Trim Active Blue Go Around Pitch Blue AP inhibit-manual trim is active. Go around pitch is active. 27-33-00 Page 7 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL MESSAGE COLOR MESSAGE DESCRIPTION Stall Protection Active Amber Angle of Attack (AOA) limiting state is active. Adjust flight condition as necessary. Stall Protection Unavailable Amber AOA data unavailable or flight control state other than normal. Continue flight within flight envelope limitations, minimum airspeed Vref. Retrim Left Wing Down Amber Retrim left wing down. Retrim Right Wing Down Amber Retrim right wing down. L-R Elevator Fail Amber Both REUs failed or loss of elevator command to both elevators. Continue flight within flight envelope limitations. Attempt FLT CTRL RESET. Elevator Single Actuator Amber Single elevator actuator failed. Notify maintenance for corrective action. Attempt FLT CTRL RESET. Vertical Coupling Data Invalid Amber Pitch Authority Limit Amber Pitch axis flight control surfaces approaching maximum displacement. Adjust flight condition as necessary. Amber Pilot and copilot pitch control column positions are different. Continue flight within flight envelope limitations. Airplane pitch response with respect to control column input may be reduced. Pitch Control Miscompare NOTE: Vertical coupling data is invalid. The FCC status information required by the flightcrew is shown on the main displays as CAS messages and synoptic page data. 5. Operation A. Elevator Hydraulic Actuation Elevator hydraulic control is accomplished by the following two types of actuators: EHSA EBHA (1) EHSA Operating States An EHSA is controlled electrically by its REU and uses hydraulic power to move the control surface. The EHSA system consists of the following three separate components: REU Hydraulic manifold Hydraulic actuator The REU is mounted directly to the hydraulic manifold. The left elevator EHSA REU receives electrical power from a single circuit breaker on the left essential dc bus. The right elevator EHSA REU receives electrical power from a single circuit breaker on the right essential dc bus. The REU receives surface position commands from the FCCs on two separate and independent BD429 data buses. One bus is from FCC No. 1 and the other from FCC No. 2. 27-33-00 Page 8 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL The REU processes the FCC signals and initiates electrical commands to the MSV solenoid and the EHSV. The MSV and EHSV control the flow of hydraulic fluid to move the actuator in the desired direction. Sensors within the manifold provide status information to the REU. These include the EHSV position LVDT, hydraulic supply and return pressure sensors and compensator position LVDT. The compensator is an LP spring-loaded accumulator that stores a small hydraulic fluid reserve. The retract and extend cylinder pressure sensors are also located in the EHSA manifold, but they provide information only to the EBHA REU. The sensors monitor the hydraulic pressure on both extend and retract chambers of the hydraulic actuator. The EBHA REU monitors similar pressure information from the EBHA actuator and compares the two pressures to insure the two actuators are working together with no force fight issue between the two. Status information in the form of a discrete signal is passed from each REU to the other. This lets the associated REU know if the other is invalid and not actively controlling the surface. The left actuator is separate from the REU and receives hydraulic power from the aircraft left system. The right actuator is separate from the REU and receives hydraulic power from the aircraft right system. The hydraulic actuators contains a single channel LVDT that provides position sensing information to the REU. There are no other electrical components in the actuator. The EHSA (outboard actuator) has the following three states of operation: Active hydraulic (normal) Damped bypass Independent surface LVDT In the EHSA active hydraulic state, the MSV is energized and allows hydraulic flow from the EHSV to the actuator. In the active hydraulic state, the REU energizes a normally open threeway MSV SOV that moves the MSV into the active position. The active position connects the cylinder ports to the EHSV and disconnects the cylinder ports from the VDO. In EHSA active hydraulic state, the REU uses the internal main ram LVDT signal to determine the main ram position and then calculates the difference between the commanded ram position (from the FCC or the BFCU) and the actual ram position to generate an error signal. The REU applies an electrical command current to the first stage coils in the EHSV that is proportional to the error signal. The EHSV command current proportionally increases the flow orifice metering area between supply pressure and one cylinder port along with the flow orifice metering area between return pressure and the opposing cylinder port. The polarity of the EHSV command current causes the ram to move in a direction that reduces the positional error signal until the error signal reaches zero. The polarity of the EHSV command current in effect determines which cylinder ports (extend or retract) get connected to supply and return pressures. The EHSA system is placed in damped bypass state when the MSV is de-energized. The state is entered when there has been a failure in the REU or the aircraft hydraulic system. A damping force is placed on the actuator since it is no longer being actively controlled, but still needs to provide sufficient damping for flutter suppression. The associated EBHA actuator, is also actively controlling the same surface and will overcome the damping force of the EHSA actuator. In the EHSA damped bypass state, the actuator may be commanded to shut down through a solenoid valve driving the MSV. The REU de-energizes the three-way MSV SOV that moves 27-33-00 Page 9 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL the MSV so that the cylinder ports are disconnected from the EHSV and interconnected through the VDO. Upon loss of electrical or hydraulic power the actuator MSV automatically reverts to the damped state. The elevator control surfaces have additional LVDT sensors that provide surface position to the REU required for the mitigation of the actuator ram LVDT disconnect failure mode. There are no other electrical components in the actuator. (2) EBHA Operating States An EBHA is controlled electrically by its REU and uses hydraulic power to move the control surface. The EBHA system consists of the following five separate components in each wing: REU MCE Hydraulic actuator HA manifold EB manifold The REU is mounted directly to the HA hydraulic manifold. Two circuit breakers are provided for each REU to allow separate wire routes from each breaker through the engine and APU rotor burst zones. The two breakers have different power sources to provide redundancy for power bus failures. The left and right elevator EBHA REU receives electrical power from two separate circuit breakers located on the UPS bus. If both the EBHA REU and EHSA REU are invalid, the MCE is capable of controlling the electrical motor and actuator on its own. In that condition, the MCE receives the surface command signals directly from one of the FCCs on the MCE A429 bus. The REU receives surface position commands from the FCCs on two separate and independent BD429 data buses. One bus is from FCC No. 1 and the other from FCC No. 2. The REU processes the FCC signals and initiates electrical commands to the MSV solenoid in the HA manifold and the PSV solenoid and EHSV in the EB manifold. Those components control the flow of hydraulic fluid to move the actuator in the desired direction. The MCE is mounted directly to the EB hydraulic manifold. Each MCE has its own 65 amp circuit breaker on the 28 Vdc EBHA bus. The MCE uses the power for its internal electronics and to power the IMPA. The MCE controls the operation of the backup electrical motor. It receives motor position and velocity information from the motor resolver. The MCE knows the validity of both the EBHA REU and the EHSA REU and receives a status discrete from each. If the EBHA REU is valid, then the REU issues the motor velocity commands to the MCE using the MCDL. The MCE passes its internal status monitors back to the REU over the MCDL. A separate hydraulic actuator is located between the HA and EB manifolds on each wing. The hydraulic actuator contains a two channel LVDT that provides position sensing information. One channel is connected to the REU and the other to the MCE. There are no other electrical components in the actuator. The left elevator actuator receives hydraulic power from the aircraft right system. The right elevator actuator receives hydraulic power from the aircraft left system. The EBHA (inboard actuator) has the following three states of operation: Active hydraulic (normal) Damped bypass 27-33-00 Page 10 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL Electrical backup (de-engerized) In the EBHA active hydraulic state, hydraulic pressure is from the aircraft system. The EHSV modulates the flow of fluid to provide the desired actuator movement. The PSV controls the state between normal and electrical backup. In the normal energized position, the valve allows the EHSV modulated aircraft hydraulic pressure to move the actuator. The de-energized position allows pressure from the self contained electrical backup hydraulic system to move the actuator. The EBHA active hydraulic state with normal hydraulic power provides closed-loop positional control of the EBHA, using the EHSV. When the EBHA is commanded into active state with normal hydraulic power, the REU and MCE energize a torque motor that positions the twoposition MSV into the active position. The active position connects the cylinder ports to the EHSV and disconnects the cylinder ports from the VDO. The REU and MCE also energize another torque motor that positions the two-position PSV into the position for normal hydraulic power. The PSV connects hydraulic system pressure to the EHSV and connects the EHSV extend and retract control ports to the ram via the MSV. In the EBHA electrical backup state the EHSV is bypassed and the starting, stopping and reversing of the electrical pump motor modulates the flow of fluid to provide the desired actuator movement. The MSV controls entry into the damped bypass state. In the energized position the MSV allows hydraulic flow during either normal or electrical backup state. Electrical backup control of a surface is only done if both the EHSA and EBHA systems do not function in their normal hydraulic state. There will not be mixed operation where an EHSA is operated in its normal hydraulic state and the EBHA is in electrical backup state. However, the electrical pump function is activated in a warm up state when there has been a hydraulic failure to the EBHA, even when the EHSA is still functioning normally. The warm up state circulates warm hydraulic fluid through the manifold and prevents it from becoming cold soaked. This insures the EBHA is ready to immediately control the surface in the event there is a subsequent failure to the EHSA that requires the electrical backup state to be engaged. In the EBHA electrical backup state, backup power provides closed-loop positional control of the EBHA, using the pump motor. When the EBHA is commanded into active state with electrical backup power, the REU and MCE energize a torque motor that positions the twoposition MSV into the active position. The active position connects the cylinder ports to the pump and disconnects the cylinder ports from the VDO. The REU and MCE de-energize the PSV torque motor, positioning the two-position PSV for backup hydraulic power. The PSV connects the pump extend and retract control ports to the ram via the MSV and blocks hydraulic system pressure from the EHSV. In the EBHA electrical backup state, positional control is provided by first comparing the commanded ram position to the actual ram position. The REU demodulates the main ram LVDT signal to determine the main ram position and calculates the difference between the commanded ram position and the actual ram position to generate the error signal. The REU then applies an electrical command current to the MCE, which commands the electrical motor driving the pump that is proportional (within limits) to the error signal. The pump motor command current proportionally increases (within limits) the pump motor velocity. The polarity of the pump motor command determines which cylinder ports (extend or retract) get connected to the inlet and outlet ports of the pump. For proper closed-loop control, the polarity of the pump motor command current causes the ram to move in a direction that reduces the positional error signal until the error signal reaches zero. The EBHA damped bypass state provides for adequate dynamic damping (imaginary) stiffness to prevent surface flutter in the event of a loss of all hydraulic pressure or electrical 27-33-00 Page 11 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL power. The EBHA may be commanded into the damped bypass state or the EBHA will default to the damped bypass state, if there is a loss of electrical power or hydraulic pressure. A damping force is placed on the actuator since it is no longer being actively controlled, but still needs to provide sufficient damping for flutter suppression. The associated EHSA actuator is also actively controlling the same surface and will overcome the damping force of the EBHA actuator. 27-33-00 Page 12 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL REU 10 REU 9 REU 8 REU 7 REU 6 REU 5 REU 4 REU 3 REU 2 REU 1 REU 15 REU 16 REU 13 REU 11 REU 14 REU 12 POWER SOURCES: LEFT SYS RIGHT SYS ELECTRIC BACKUP TIL-003719 Actuator Control and Hydraulic Power Sources Figure 1 27-33-00 Page 13 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL SEE DETAIL A EB MANIFOLD EBHA ACTUATOR HA MANIFOLD MCE EHSA ACTUATOR REU EHSA MANIFOLD REU SURFACE LVDT DETAIL A TIL-003577 Elevator Actuation System Figure 2 27-33-00 Page 14 August 15/14