Pneumatics.docx

2A-36-10: General Pneumatics The pneumaticsystem uses high temperature pressurized airfrom the compressor section of the left and right engines, Auxiliary Power Unit (APU) bleed air or an external air cart to supply the following airaaft systems that require a modulated pneumatic source: Air conditioning and pressurization Pressurization safety valve V\ling anti-ice Engine starting Aircraft water system Total Air Temperature (TAT) probe airflow (ground only) Airflow is supplied to aircraft systems through a bleed air manifold connected to both enginesand the APU. The manifold also hasa connection to allow an external cart to provide pressurized air for engine starting or air conditioning on the ground. Air supplied by the engines is temperature and pressure regulated by Bleed Air Controllers (BACs) that monitor the air supply via sensors within the ductwork. The engine BACs draw air from either the 5th (mid-stage) or the higher temperature 8th (high stage) of the compressor sections of the engines, depending upon the engine power settings and bleed air demand. The temperature of the air is regulated by selective switching between compressor stages for a source of supply air and by passing the supply air through a precooler heat exchanger that uses ambient air drawn into the engine at the fan intake stage of the compressor. Pressure is controlled through regulator and shutoff valves that vary the size of the valve orifice in the manifold.Air supplied by the APU or a ground cart is not regulated. The temperature and pressure of air from the APU is a function of APU speed and ambient conditions. APU bleed air is used primarily only on the ground for air conditioning and engine starting. A full description of the pneumatic system components can be found in: 2A-36-20: Pneumatic System Control and Indication OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10-02 2A-36-00: 1of 14 Figure 1.ECS I Pressurization Synoptic TIL-033847 2A-36-20:Pneumatic System Control and Indication 1. General Description: The pneumatic system providescontrol,regulation and monitoringofthe bleed airtemperature, pressure and airflow inthe left and right bleed air manifolds. OEM Provided Dal.a Pneumatlca BA.SICISSUE 2014 10.{)2 2A-36-00:2 of 14 Bleed air services the cabin air conditioning, wing leading edge anti-ice, engine anti-ice and engine starting, aspiration of the airaaft total temperature probes and other miscellaneous bleeds.Digital controllers are used to accomplish the controlling functions as well as providing display information via the ARINC 429 data buses and disaete inputs into the Modular Avionics Unit (MAU) for fault messages andvisual representation onthe Environmental Control System I Pressure synoptic page. The bleed air system consists of the following subsystems: Engine and APU Bleed Air Flow Control and Regulation Temperature Regulation Distribution Ducting Pressure Indication Description of Subsystems, Units and Components: (See Figure 3. Pneumatics System Diagram.) Engine and APU Bleed Air: The engine and APU bleed air system provides bleed air to the Environmental Control System (ECS). The ECS supplies air for cabin pressurization and air conditioning, airframe and engine anti-icing. The engine bleed air ducting provides a path for 5th and 8th stage bleed air to the bleed air manifold. The APU Load Control Valve (LCV) is connected to the aircraft bleed ducting and is controlled from the BLEED AIR panel (see Figure 2. Pneumatics System Controls and Indications) located on the Cockpit Overhead Panel (COP). The ON (depressed) position automatically opens the LCV. After it is opened, the Electronic Control Unit (ECU) controls the pneumatic load through the LCV position. The engine and APU bleed air system provides bleed air to the ECS. The ECS supplies airfor cabin pressurization I conditioning and wing I engine anti-icing. This system also provides for engine starting using bleed air from the APU or the other engine. After the engine is started, bleed air is produced. The offtakes for the engine 5th and 8th stage compressor are located on the bottom of the engine. High Pressure 5th stage (HP 5) bleed air flows from the 5111 stage offtake, through the ducting to the Thermal Anti-Ice (TAI) duct and the Pressure Regulating and Shutoff Valves (PRSOVs). High Pressure 8th stage (HP 8) bleed airflows from the 8th stage offtake tothe High Pressure Shutoff Valve (HPSOV). As long as the engine is operating, bleed air is always available for the TAI system, even when the respective bleed air system is selected OFF. VVhen the L ENG or R ENG switch (BLEED AIR panel, COP) is selected "ON , the PRSOV opens and allows HP 5 bleed air to flow to the respective side ECS and to the air starter ducting. The PRSOV controls the supply of bleed air to the ECS from the engine. OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10-02 2A-36-00: 3 of 14 When ECS system demand is greater than HP 5 supply, the HPSOV opens, allowing HP 8 airto supplement the bleed airsystem. The HPSOV is regulated by a sense line downstream of the servo pressure regulator I torque motor. When HP 8 bleed air is being supplied and HP 8 pressure is greater than HP 5 supply, the non-return valve doses, preventing a backflow of bleed air into the 5t11 stage compressor section. If the left or right bleed airsystem isinoperative, bleedair may be provided to the opposite system by selecting the ISOLATION switch to "ON" (BLEED AIR panel, COP). Selecting the ISOLATION switch to "ON" allows the bleed air isolation valve to open thereby permitting a crossflow of bleed air between the left and right systems. If one side of the ECS system is inoperative andthe respective L ENG or R ENG bleed air switch is selected on, the 113'=tj.1•jtf11 (caution) message will be displayed. High-Pressure Shutoff Valve (HPSOV): There are two HPSOVs, one per engine. The HPSOV inlet is connected to the high-pressure stage 8 bleed air duct and the outlet is connected to the high-pressure stage 5 / stage 8 interface Y-duct. HP 8 bleed air to the ECS is controlled by the HPSOV. Bleed air extraction from the engine Bt11 stage is controlled by the 3.5 inch diameter HPSOV. This is a spring-loaded dosed, pneumatically operated, butterfly type modulating and shutoff valve. The HPSOV contains a spring-loaded closed butterfly valve dosure element and a piston-type pneumatic actuator. An actuator (servo) pressure connection and a downstream pressure sense connection are provided to interface with the servo regulator I torque motor. A position indicator is located on the top of the HPSOV to indicate valve position. High-Pressure Stage 5 (HP 5) Air Non-Return Valve: There are two HP 5 non-return valves, one per engine. The valve is installedin the high-pressure stage 5 /stage 8 interface Y-duct on the end of the Y-duct connected to the high-pressure 5th stage bleed air duct. The valve is a 4 inch diameter,insert-type, split flapper check valve. It consists of a mainvalve housingwith integral seat, two semicircular spring-loaded flaps hinged on a pin and an open-position stop that minimizes wear due to aerodynamic flutter. The valve flanges incorporate an anti-rotation pinfor proper orientation in the bleed air duct. When the HPSOV is dosed, HP 5 air flows through the air non-return valve to the ECS. When the High-Pressure stage (HP 8) air flows into the bleed air duct system through the HPSOV, the HP 8 air pushes against the non-return valve flaps, closing the non-return valve and preventing HP 5 air from flowing to the ECS. This prevents the backflow of bleed air into the 5th stage compressor section. OEM Provided Data Pneumatlc:e BASICISSUE 2014-10-02 2A-36-00: 4 of 14 Pressure Regulating and Shutoff Valve (PRSOV): There are two PRSOVs, one per engine. The PRSOV inlet is connected ta the high-pressure stage 5 / stage 8 interface Y-duct and the PRSOV outlet is connected ta the combined bleed air duct. The PRSOV controls the supply of bleed air ta the ECS. The PRSOV is a spring-loaded closed, butterfly type, pressure regulating and shutoff valve that has a regulation set paint of 40.5 psig (279.2 kPA). The PRSOV is controlled by the L and R ENG switches in the BLEED AIR section of the COP. The switches, when selected ON, provide 28V DC ta energize the solenoid of the respective valve, allowing the PRSOV ta open and begin regulating bleed air flaw ta the aircraft. A relief is incorporated into the PRSOV in order to limit actuation pressure in the event of a reference regulator failure. A position indicator is located on top of the PRSOV housing to indicate valve position. High-Pressure Stage 5 / Stage 8 Interface Y-Duct: There are two HP 5 I HP 8 interface Y-ducts, one per engine. The Y-duct is connected ta the HP 5 duct, the HPSOV and the PRSOV. TheY-duct hasthreeflanges. At each flange, theY-duct is connected ta the other duct I valves with a V-band coupling clamp. Airleakage at the flanges is prevented by the E-seals installed between the mating flanges. The Y-duct has a flexible gimbal section to prevent damage ta the duct during engine expansion and movement. Flaw Control and Regulation: The bleed air flaw control and pressure regulation system provides control, regulation and monitoring of the bleed air temperature, pressure and flaw in the left and right bleed air manifolds. The bleed air controllers (digital) control the bleed air system. The controllers provide information for display through the ARINC 429 data buses, discrete inputs into the CAS for fault messages and visual representation an the Environmental Control System I Pressure synoptic page. During ground operation, the normal position of the bleed air isolation shutoff valve is normally closed except for the following switch conditions: APU bleed air switch selected ON MASTER - START switch is selected ON MASTER - CRANK switch is selected ON ISOLATION bleed air switch is selected open During flight operation, the normal position of the bleed air isolation shutoff valve is normally closed except for the following switch conditions: MASTER - START switch is selected ON MASTER - CRANK switch is selected ON ISOLATION bleed air switch is selected open 8th Stage Valve Servo Regulator and Torque Motor: OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10-02 2A-36-00: 5 of 14 The two 8th stage valve servo regulator and torque motors are located on the bottom of each engine. The regulator I torque motor is installed on a bracket on the bottom of the bypass duct adjacent to the 8th stage bleed air offtake. The flow of 5111 stage bleed air is controlled by the regulator I torque motor. The servo regulator and torque motor unit is a diaphragm-actuated, poppet-type regulator combined with an electromagnetically-actuated modulating valve (torque motor) at the outlet. The unit is spring-loaded open and pneumatically actuated. It includes a relief valve for limiting overpressure and has a dual diaphragm for increased reliability. The regulator I torque motor provides pressure for control of the HPSOV proportional to the torque motor input power level, which is provided by the Bleed Air Controller (BAC). With the two air conditioning packs turned on, the control set point is 14 psig. During one pack operation, the nonnal control set point is 35 psig. In nonnal two pack operation, the descent mode set point will vary depending on aircraft configuration. The supply inlet connection receives 8th stage pressure from upstream of the HPSOV. The regulator pressure outlet is capped and not used. The controlled pressure outlet is connected to the opening chamber of the HPSOV. During wing anti-ice modes, the HPSOV provides temperature augmentation by mixing 8th stage air with 5th stage air and changes the temperature control set point at the precooler inlet to 630°F (332°C). Inlet pressure is ported through an orifice to the bleed-on metering valve. If the supply pressure is below the regulation pressure, the bleed-on metering valve is open and the supply airflows through the valve. The air flows past the orifice to the regulator diaphragm, the relief valve, the torque motor and out of a vent orifice. As inlet pressure reaches the level of regulated pressure, the diaphragm force balances the force of the regulator spring and moves the bleed-on metering valve toward the dosed position. As flow demand changes, the diaphragm modulates the bleed-on metering valve position to maintain the required regulated pressure to the torque motor. Servo Regulator and Torque Motor Filter: The servo regulator and torque motor filter is installed in the high-pressure stage 8 bleed air duct. The filter is installed between the duct and the sense tube connected to the input for the servo regulator and torque motor. The filter is a 60 micron filter and is designed to eliminate soot contamination in the regulator I torque motor. Sense Tubes: OEM Provided Data Pneumatlc:e BASICISSUE 2014-10-02 2A-36-00: 6 of 14 The sense tubes are installed between the valves, duds and the regulator I torque motor in various places on each engine. The sense tubes assist in valve actuation. Bleed Air Controllers (BACs): The BACs are installed on the aft side of the baggage compartment bulkhead. The units are digital, microprocessor-based and are designed to automatically regulate bleed air manifold supply pressure and temperature. They are capable of controlling bleed air for all systems utilizing bleed airwithinthe capacity of the engine over the entire aircraft operating envelope. The BACs control the corresponding left or right side regulator I torque motor, fan air valve and wing anti-ice valve torque motors in response to associated pressure and temperature inputs. The left BAC controls the left bleed air system and the right wing anti-ice system. The right BAC controls the right bleed air system and the left wing anti-ice system. Note VVing anti-ice control is provided by a separate channel in each controller. The left BAC microprocessor is co-powered by 28V DC from the left Essential DC bus through the BLD AlR CTRLR L and the WING ANTI-ICE L circuit breakers. The right BAC microprocessor is co-powered by 28V DC from the right Essential DC bus through the BLD AIR CTRLR R and the WING ANTI-ICE R circuit breakers. VVhenever aircraft power is available, the controllers are powered to allow temperature and pressure to be displayed on the ECS I Pressure synoptic page. If multiple BAC processor corrections are required during flight, the operations monitor inthe BAC locks out the BAC processor operation and annunciates the fault through an output discrete. The BAC can be reset by cycling electrical power to the BAC off and on.The BACs transfer data to the modular avionics units through the ARINC 429 bus. Bleed Air Isolation Shutoff Valve: The bleed air isolation shutoff valve is installed in the bleed air manifold in the tailcompartment. When closed, the valve isolates the left and right bleed air systems from each other. VVhen open, the valve allows the flow of bleed air between the left and right bleed air systems. The valve can be manually opened I closed by selectingthe ISOLATION bleed air switch to open I close. The valve automatically opens with either bleed air I engine start relay and the APU switch (ground only). The valve can be manually wrenched andlocked open during ground operation. OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10-02 2A-36-00: 7 of 14 The bleed air isolation shutoff valve is a normally dosed, solenoid-actuated open and pneumatically-driven open valve. The valve contains a single-pole, double-throw position switch used to provide discrete logic to illuminate the bar on the ISOLATION bleed air switch (indicating open) and for the {advisory) CAS message. Isolation Valve Open The spring-loaded position of the solenoid valve vents the actuator opening chamber (Chamber A) and the actuator spring drives the butterfly plate to the closed position. When the solenoid valve is energized, the ball strokes to block the vent port and allow control-regulated pressure to enter Chamber A. Either manifold Qeft or right) must be pressurized to provide air through the sensing selector to the control pressure regulator. As Chamber A pressurizes, the valve strokes open and actuates the open position switch. Auxiliary Power Unit (APU) Check Valve: The APU check valve is installedin the APU air supply duct inthe tail compartment. The check valve is a 3.5 inch (88.9 mm) diameter, insert type, split flapper check valve. The valve features an open position stop that minimizes wear due to aerodynamic flutter and an anti-rotation pin for proper orientation in the duct. When the APU is running and APU bleed air pressure is higher than engine bleed air pressure, the APU check valve opens to allow APU bleed air to flow to the bleed air manifold. When engine bleed air pressure exceeds APU bleed air pressure, the APU check valve doses,preventing the reverse flow of air into the APU. (7) Bleed Air Control Switches: The bleed air control switches are located on the BLEED AIR panel of the COP (see Figure 2. Pneumatics System Controls and Indications). The L ENG and R ENG switches are used to select the left and right engine bleed air ON or OFF. The APU switch is used to select the APU bleed air ON, allowing APU bleed airto be used as a bleed air source while the aircraft is on the ground. The APU bleed air switch also opens the bleed air isolation shutoff valve. TheISOLATION switch is used to manually open and closethe bleed air isolation shutoff valve. Opening the shutoff valve allows bleed air from the left or right bleed air system (whichever is operating) to pressurize the opposite system. When the switch is selected on, there will be a lighted bar on the switch capsule,which indicates the isolation valve is open. When the switch is selected off, the face of the switch capsule will be black. (8) Bleed Air I Engine Start Relay: OEM Provided Data Pneumatlc:e BASICISSUE 2014-10-02 2A-36-00: B of 14 The bleed air I master start I master crank relays are independent of one another and are located in the Left Electronics Equipment Rack (LEER). The relays open the isolation valve during the start I crank cycle. Temperature Regulation: One function of the bleed air system is temperature regulation. To avoid high temperatures inside the aircraft, fan air is used as a cooling medium together with a bleed air precooler located in each pylon. Fan Air Valve: The fan air valve is a pylon-mounted, spring-loaded open, pneumatically actuated, modulating and shutoff type valve with a torque motor that is controlled by its onside bleed air controller. The musde pressure for the valve control is provided by the servo pressure regulator, which is upstream of the manifold pressure regulator valve. The valve is used to control the amount of fan air through the precooler to limit the temperature of the air in the bleed air manifold to no more than 520°F (271°C) over the entire aircraft operating envelope. Included are minimum miscellaneous bleed flows to the maximum of one pack plus two wings and miscellaneous bleed flows. Temperature at the precooler outlet is controlled to 400 ±10°F (204 ±5°C) in normal operating condition with wing anti-ice off orwith wing anti-ice and both engine bleed air on within the engine capacity. Precooler outlet temperature is controlled to 500 ±10°F (260 ±5°C) during single bleed operation with one wing anti-ice on or with one winganti-ice on and the other winganti-ice offwithin engine capacity. Bleed Air Temperature Servo Pressure Regulator Torque Motor: The bleed air temperature servo air regulator and torque motor is a diaphragm-actuated, poppet-type regulator combined with an electromagnetically-actuated modulating valve (torque motor) at the outlet. The unit is spring-loaded open and pneumatically actuated.It includes a relief for limiting overpressure and has a dual diaphragm for increased reliability. The unit provides pressure for the control of the high-stage valve proportional to the torque motor input power level provided by the bleed air controller. With two packs selected to on, the control set point is 14 psig.During one pack operation the normal set point is 35 psig. Descent mode set pointwhen in normal two pack operation will vary depending on aircraft configuration. During wing anti-ice on modes, the high-stage provides temperature augmentation by mixing the high-stage air with mid-stage air and changes the temperature control set point at the precooler inlet to 630°F (332°C). Bleed Air Precooler: OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10-02 2A-36-00: 9 of 14 The engine bleed air precooler, mounted in the pylon heat exchanger, is a heat exchanger with single-pass, crossflow, plate and fin assembly of brazed and welded construction. Hot bleed air enters through the bleed air inlet and exits out through the bleed air outlet. The cooling air from the engine fan enters 90° from the bleed air inlet into the fan air inlet, cross-flows through the heat exchanger to the opposite side and exits through the fan air outlet. The left and right precoolers differ in port configuration and mounting provisions required to adapt to each pylon. Depending on engine power settings and use of mid-stage or high-stage extraction, bleed air temperatures may vary widely. Since all engine bleed air flows through the precooler, additional cooling capability is sometimes required. Engine fan air crossflows for cooling when necessary. The bleed air controller monitors precooler outlet temperature and modulates the opening of the fan air valve as required. Bleed Air Precooler Inlet Temperature Sensor: A precooler inlet temperature sensor is mounted in each nacelle. It is a single temperature sensing element and a connector. The temperature sensor is a hermetically sealed unit that uses a platinum element to sense the precooler inlet air temperature. The temperature information upstream of the precooler is used for control of the precooler bleed air temperature via the ARINC 429 data bus from the BAC to its onside MAU for display on the Environmental Control System I Pressure synoptic page. Bleed Air Precooler Outlet Temperature Sensor: The precooler outlet temperature sensors are mounted in the tail compartment. They are single temperature sensingelement and a connector. Like the inlet temperature sensor, the outlet temperature sensor is a hermetically sealed unit that uses a platinum element to sense the precooler outlet air temperature. The temperature information downstream of the precooler is used for control of the precooler bleed air temperature via the ARINC 429 data bus from the BAC to its onside MAU for display on the ECS I Pressure synoptic page. Distribution Ducting: The distribution duct system delivers bleed air from the source to the bleed air manifold, where it is distributed to the using systems. The distribution ducting system consists of the following subsystems: Bleed Air Manifold Ducting Precooler Ducting External Air Connection Ducting Bleed Air Manifold Ducting: OEM Provided Data Pneumatlc:e BASICISSUE 2014-10-02 2A-36-00: 10 of 14 The bleed air manifold receives bleed air from the engines and APU. It provides a distribution point for the bleed air to the using systems. Precooler Ducting: The precooler ducting provides a path through the precooler where the air is cooled by fan air to a temperature nominal for operating conditions. ...-C-a.- -n.- . DO NOT CONNECT AN EXTERNAL AIR SOURCE WITH ELECTRICAL POWER OFF. External Air Connection Ducting: External air connection ducting provides a path for an external air source used to service the aircraft pneumatic systems during ground operations. The ground connection check valve is located in this duct. The ground connection check valve opens to permit the flow of air from the ground cart into the bleed air manifold and closes when the engine or APU bleed air pressure exceeds the ground cart air pressure. Pressure Indication: The pneumatic indicating system provides the left and right bleed air manifold pressures and over-pressure switch signal information to the ECS I Pressure synoptic page and the Crew Alerting System (CAS). Bleed Air Manifold Pressure Sensor: The left and right bleed air manifold pressure sensors are located downstream of the precoolers, in the tailcompartment. The bleed air manifold pressure sensors provide the means to display and control the bleed air manifold pressure. The bleed air manifold pressure sensor provides the means to sense the manifold pressure from 0-75 psig (5.27 kg/sq cm). The unit is a non-repairable, silicon strain gage type pressure sensor. It is used by the bleed air controller for control as well as the source of manifold pressure for display via the controllers ARING 429 data bus. Controls and Indications: Circuit Breakers (CBs): The following CBs protect the pneumatic system: Circuit Breaker Name CB Panel Location Power Source BLDAIR CTL CMD L MCDU SSPC (# 3601) L ESS 28V DC BLDAIR CTLCMD R MCDU SSPC (# 3602) R ESS 28V DC BLDAIR CTRLR L 1 MCDU SSPC (# 3603) L ESS 28V DC BLDAIR CTRLR L 2 MCDU SSPC (# 3604) R ESS 28V DC BLDAIR CTRLR R 1 MCDU SSPC (# 3605) R ESS 28V DC OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10-02 2A-36-00: 11 of 14 Circuit Breaker Name CB Panel Location Power Source BLDAIR CTRLR R 2 MCDU SSPC (# 3606) L ESS 28V DC BLEED AIR ISO SOL MCDU SSPC (# 3607) L ESS 28V DC WING ANTI-ICE L MCDU SSPC (# 3016) L ESS 28V DC WING ANTI-ICE R MCDU SSPC (# 3017) R ESS 28V DC Crew Alerting System (CAS) Messages: The following CAS messages are associated with the pneumatic system: Area Monitored CAS Me&Hge Bleed Air Controller interface with MAU Bleed Air Switch Relay 113=M•1tt!i (caution) ll;l:Fj1• •lll (caution) Precooler Inlet I Outlet Temperature L-R Bleed Air Ho (caution) APU Bleed ON with APU not up to operating speed or Engine Bleed not selected ON Bleed Configuratio (caution) Bleed Air Manifold Pressure Sensor L-R Bleed Pressure Hig (caution) Bleed Air Manifold Pressure Sensor L-R Bleed Pressure Lo (caution) Supply Manifold Isolation valve Switch Isolation valve Ope (advisory) Limitations: Flight Manual Limitations: The APU can be operated on the ground, during takeoff, in flight and during landing. In flight it is an optional source of eledrical power via the APU GEN instead of one or both engine-driven generators. The APU cannot be used to supply pressurization airflow in flight. The APU may be used for starter-assisted main engine starts at and below 30,000 ft if required. OEM Provided Data Pneumatlc:e BASICISSUE 2014-10-02 2A-36-00: 12 of 14 Figure 2. Pneumatics System Controls and Indications SEE DETAILA L ENG I R ENG BLEED AIR When eelec:ted to ON: Amber OFF legend is extinguished. Essential (ESS) 28V DC Bus power is provided to the associated system (L ESS DCfor L ENG side; R ESS DC for R ENG side). Associated Bleed Air Controller performs BIT check and establishes operational parameters. Associated manifold pressure regulator valve is opened,allowing bleed air to using 8Y'ltelll8. APU bleed air is inhibited when sufficient engine bleed airis available (APU Bleed Air lnteock). When selected to OFF: Amber OFF legend illuminates. Associated manifold Pl1'88ul1' regulator valvedOAll. Power i•removed from a890Ciated sylltem. APU air is available when salected. DETAIL A TIL-001637A OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10.02 2A-36-00: 13 of 14 Figure 3. Pneumatics System Diagram --- I 3 ,.,.,_. F""' - -- = - -1= = = - - - - .J BtEm - -r f11-- - -- _-:-= - == i--:b""' I ,.,.,_. I -- - 3 ""' TIL-001638A OEM Provided Data Pneumatlc:e BASIC ISSUE 2014-10..02 2A-3S.OO: 14 of 14

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