FightSafety

FightSafety GIV/G300/G400 PILOT TRAINING MANUAL CHAPTER 11 AIR CONDITIONING INTRODUCTION The air-conditioning and temperature control systems for the Gulfstream IV provide for comfortable cabin and cockpit temperatures throughout the complete operating enve- lope of the aircraft. The normal source of air for air conditioning is bleed air from the engines. The APU is an alternate source and provides heating and cooling of the occu- pied areas when the aircraft is on the ground. An approved external air supply can be connected to an adapter to provide air conditioning on the ground when the other air sources are not available. GENERAL the air-conditioning system consists of a three-wheel air-bearing air cycle machine (ACM) packaged refrigeration unit, in which control over the cabin and cockpit temperature Is accomplished by means of mixing hot com- pressed air and refrigerated compressed air. The dual pack concept provides redundancy 1rt case one unit fails. The term air cycle means that cooling is provided by means of a ther- modynamic cycle, using only air as the medium (as opposed to vapor cycle systems, which employ Freon or other similar gases). The sys- tem also employs water separation for humid- ity reduction. AIR CONDITIONING FOR TRAINING PURPOSES ONLY EFTA01119971 UNINOWONO3 81V GIVIG300/6400 PILOT TRAINING MANUAL SYSTEM DESCRIPTION AND OPERATION GENERAL During normal in-flight operation, hot com- pressed air is supplied from the bleed-air man- ifold (Figure 11-1). This air, which is I RAM I LEGEND a Hot AM a WNW NA a FAN ma Ili ^PUMA ow MA FILTER GPI) CCNNECTOR FlightSafety te m pe rat u re and pressure-controlled, can be obtained from either or both engines at the se- lection of the crew. Cooling is provided by air cycle cooling equipment (Figure 11.2), consisting of a primary heat exchanger, a secondary heat exchanger, and an air cycle machine, which are capable of reducing the temperature of the air from the bleed-air man. ifold to values above freezing. Humidity re- duction is accomplished by a mechanical PRESSURE RE:A/JCR CYJR0CARC COCKPJ RIR CONDI- NG SO vA.. VF OVERBOARD REcc,RTOR Figure 11-1. Bleed-Air Manifold R ENG 11-2 FOR TRAINING PURPOSES ONLY EFTA01119972 TEMPERATURE CONTROL VALVE TORQUE MOTOR FOR TRAINING PURPOSES ONLY -a CO REAR PRESSURE BULKHEAD COCKPIT MANUAL TEMPERATURE CONTROL VALVE COCKPIT PNEUMATIC OVER TEMP SENSOR TO COCKPIT ORFICE CABIN SILENCER CABIN DUCT TEMPERATURE SENSOR CABIN PNEUMATIC OVER TEMP SENSOR CABIN MANUAL TEMPERATURE CONTROL VALVE REAR PRESSURE BULKHEAD TEMPERATURE CONTROL VALVE TORQUE MOTOR WATER SEPARATOR SECONDARY HEAT EXCHANGER ASPIRATOR STATIC PRESSURE VALVE RAM-AIR CHECK VALVE TEMPERATURE CONTROL VALVE COOLING TURBINE TEMPERATURE CONTROL VALVE ANTI- CE VALVE OVERBOARD COMPRESSOR BYPASS OZONE FILTER CHECK TO OVER TEMPERATURE VALVE LIGHT (ON AT BYPASS •50? SWITCH) DOOR ANTI-ICE VALVE Figure 11-2. Air-Conditioning System PRIMARY HEAT EXCHANGER OZONE FILTER OVERBOARD AIR COND SOV AIR COND SOV GIV/G300/G400 PILOT TRAINING MANUAL AIR CONDITIONING EFTA01119973 1 m10300/6400 PILOT TRAINING MANUAL water separator. Temperature control .of the occupied areas is accomplished by rying t amounts of hot bleed air which bypasses the cooling equipment. Separate temperature con- trol is provided for the cabin and the cockpit with controls located on the overhead panel .n the cockpit. A manual system provides addi- tional control over the system in the event of a failure of the electronic control components. A feature of the air-conditioning system is that it functions independently when on the ground. Although the main engines are not operating, and without a ground pneumatic supply (ground cart) or external electrical supply, complete air- conditioning is provided by the APU supplying the bleed-air manifold. Ground operation of the air-conditioning system is essentially the same as in flight, with the addition of ram-air flow across the heat exchangers induced by Figure 11-3, ISOLATION Valve Switch Flightsafe 7 cooling fans. Provisions are also made foranet. ternal air connection for use with an external ground source of bleed air for the bleed-air manifold. Should either or both engines be operating e crew may select either or both engines as a sup. ply of hot compressed air for the bleed -air manifold and thus the air-conditioning system. This is accomplished by use of the IS0LA- TION valve switch (Figure 11-3). Ram-air ventilation is provided from the dorsal fin ram-air duct (Figure 11-4) during certain emergency procedures. 11-4 FOR TRAINING PURPOSES ONLY EFTA01119974 FlightSafety vs_ties: GIV/G300/G400 PILOT TRAINING MANUAL Figure 11-4. Dorsal Fin Ram-Air Inlet AIR CONTROL COMPONENTS Bleed-Air Manifold The bleed-air manifold is used as the source of bleed air for the air-conditioning system. This air Is available from one or both engines, the APE, or an external air supply (ground use only). The bleed-air manifold delivers air to using systems, one being the air-conditioning sys- Ann ien1; The air temperature is approximately U at a maximum of approximately 40 psig. The air is delivered to the air-conditioning shutoff and flow-regulating valves (shutoff fold in the tail Air-Conditioning Shutoff and Flow-Regulating Valves These valves serve two functions in the air- conditioning system: • As a shutoff valve for the air-condition- ing system when system operation is terminated. • As a flow regulator when the air- conditioning system is in operation. The valve is a pneumatically operated de- vice with an internal electrical solenoid. An internal shutoff electrical solenoid, when energized, closes this valve, pre- venting any air from entering the air-con- ditioning system and ending operation of the system. With a source of air in the bleed-air manifold and the shutoff sole- noid deenergized, the valve butterfly moves toward the open position and air- flow starts again. This valve functions as a flow-regulating device to maintain a maximum of 28 ppm airflow. Electrical shutoff solenoid energizing causes the valve to be pressurized to the fully closed position. There are several ways to energize the solenoid and close the valve: • Place the RAM AIR switch to RAM. • Place the right or left PACK control switch off. • When on the ground, aircraft SNs 1156 and subsequent and those with ASC 135, selecting the START or CRANK MAS- TER switch ON will close the left valve. • On the ground, the discharge side of either ACM compressor has reached 450°F. • When on the ground, depress either en- gine starter switch. AIR CONDITIONING FOR TRAINING PURPOSES ONLY 11-5 EFTA01119975 01V/G300/0400 PILOT TRAINING MANUAL TEMPERATURE CONTROL SYSTEM It is the position of the temperature control valve (Figure 11-5) which determines compart- ment temperature by mixing hot and refriger- ated air to attain the desired compartment temperature. In order to control the compartment temper- ature. the position of the appropriate temper- ature control valve must be varied accordingly. All temperature control devices in this system are directed toward the control of the temper- ature control valves. Cabin/Cockpit Temperature Selector General The dual selector (see Figure 11-3) is used to automatically or manually set a desired cabin or cockpit temperature. Both are physically and operationally independent from the other and are installed in the cockpit overhead. Operation The selector provides automatic and manual temperature control selection by rotation of the control knob clockwise and counterclockwise from the 9 o'clock OFF position. The control functions are obtained through approximately 330° rotation of the selector shaft. There is a de- tent region of approximately 20 to 30° at the OFF position, within which no signal is appl to the temperature control valve from eitheried the manual selector or the temperature controller. Rotating the shaft out of this detent area in a places the temperature con- clockwise direction trol system in the automatic mode of operation at the minimum selectable temperature (60°F) Further clockwise. rotation through 150° of rotation linearly increases the selected temper- ature to the maximum value (gooF). amm Th inafety Rotation of the selector knob out of the detem area in the counterclockwise direction places the temperature control system in the manual although still electric, mode of operation with . the temperature control valve fully closed. Further rotation of the knob through 150° in the counterclockwise direction progressively opens the valve to the fully open position, thereby increasing the temperature. Some aircraft have been outfitted with addi- tional manual temperature controls located aft of the baggage door. These pneumatic con- trols are dependent on a minimum 3 psid cabin pressure for opening of the temperature con- trol valves. Cabin/Cockpit Temperature Control Valve The temperature control valve is a two-inchdi- ameter pneumatic modulating butterfly valve. With no pneumatic pressure applied to itsdi- aphragm chamber, an internal spring mecha- nism maintains the butterfly in the closed position. The valve requires pneumatic pres- sure to open the butterfly and the amount of openin is controlled b varying the pro' matic pressure applied. The pneumaticcontrol pressure (left servo control system) originates soularetoirsathoedntororquoteedmtootaosrervo air at a T-fitting upstream of the valve. Duct pres • h addi. Some aircraft have been outfitted vat ,.0 otifotnhael hmaagnguaaglet door. em rTahtuesree controls locatnetravis pressureter are dependent on a minimum Pri3ePusmidatcjacbtP-relOsi; sure for opening of the temperature con 114 FOR TRAININn EFTA01119976 FOR TRAINING PURPOSES ONLY COCKPIT PNEUMATIC OVERTEMP TO SENSOR - COCKPIT ORIFICE CABIN SILENCER I - - ------ CABIN DUCT TEMPERATURE SENSOR TEMPERATURE CONTROL VALVE TORQUE MOTOR SUPPLY AIR FROM RIGHT SERVO CONTROL SYSTEM TEMPERATURE CCNTFOL VALVE ANTI-ICE VALVE WATER SEPARATOR STATIC — PRESSURE VENT RAM-AIR ACM CHECK VALVE BYPASS VALVE COOLING TURBINE HEAT MUFF T I HEAT EXCHANGER fl to OVERBOARD COMPRESSOR I er a . .mS ASPiRATOR BYPASS DOOR CHECK VALVE TO CNERTEMPERATURE LIGHT BYPASS Pm sso• F) -0- COORS SWITCH PROAARY HEAT 0 —rS . ► EXCHANGER 46 ■ N. S e / • ANTI-ICE VALVE OVERBOARD 0 F 0 2 LEGEND WARM AIR ■ CONDITIONED AIR TEMPERATURE CONTROL VALVE SUPPLY AIR FROM LEFT SERVO MI COLD AIR CONTROL SYSTEM RAM AIR In PRIMARY HEAT EXCHANGER K SECONDARY HEAT FXCHANGER Co' TEMPERATURE CONTROL VALVE TORQUE MOTOR REAR PRESSURE HOT BLEED AIR BULKHEAD Figure 11-5. Refrigeration Unit AIR CONDITIONING EFTA01119977 9NIN01110NO3 1:111/ Rig% WV/0300/0400 PILOT TRAINING MANUAL ..• Cabin/Cockpit Temperature Controllers The crew exercises control over the compart- ment temperature by manipulation of the se- lector rheostat, located on the overhead panel in the cockpit. Manually moving the rheostat changes the resistance, and this change is re- flected back to the controller, thereby adjust- ing the desired temperature. Five temperature-sensitive elements, two cabin/cockpit temperature sensors, one cock- pit temperature sensor, and two cabin/cockpit duct temperature anticipators, supply addi- tional information electrically to the cabin/cockpit temperature controller relating compartment temperature, duct temperature, and the temperature of the air exhausted from the compartment involved. These factors are compared to the desired temperature infor- mation from the selector rheostat and solid- state controller, and then a DC output signal is routed to the air pressure regulator valves which control the cabin/cockpit temperature control valve positions. Additional functions of the anticipator are to provide a rate of change control over the system and also to sense when the duct temperature has reached the maximum allowable value. Cabin/Cockpit Temperature Sensors The temperature sensors are dual-element, consisting of two separate sections. One sec- tion provides temperature information to the cabin/cockpit temperature controllers, while the other element is actually a temperature bulb for the cabin air temperature indicator (digital), the overhead panel in the cockpit. 11-8 Crossover Function Operation To pressurize both refrigeration units using both engines, position the L and It ENC BLEED AIR switches to ON. This energizes both bleed-air pressure regulator and shutoff valves open, allowing bleed-air pressure to the air-conditioning shutoff and control valves Placing the L and R PACK switches to ON al. lows bleed air to flow through these valves to the refrigeration units, where it is conditioned to the desired temperature and routed to the cabin/cockpit. In the event of the loss of one engine, place the BLEED AIR switch for the operating engine to ON and the inoperative engine BLEEDAIR switch to OFF. Placing the ISOLATION switch to OPEN allows the single engine to pressur- ize the whole bleed-air manifold. For full air conditioning place the L and R PACK switches to ON. In the event of the loss of one refrigeration unit. place the inoperative side PACK switch to OFF, and ensure that the BLEED AIR switch and PACK switch for the operating side are in ON. With the PACK switch for the operative side ON, bleed air is routed from the engine through the air-conditioning system shutoff and control valve and through the operating re- frigeration unit to the cabin or cockpit. NOTE Crossover plumbing allows condi- tioned air from the operating pack to feed into the area of the aircraft with the pack selected off. In addition to the source selection sw itches. there are two TEMP CONTROL knob,. with AUTO, OFF, and MANUAL positions, that vary temperature range setting from HOT to COLD. During dual-pack operation cab n and cockpit temperatures are indepenclent!:. reg- ulated. Cabin and cockpit temperature, may be monitored by digital readouts located di- rectly above the TEMP CONTROL kw's. FOR TRAINING PURPOSES ONLY EFTA01119978 GIV/G300/G400 PILOT TRAINING MANUAL FightsafetY sealant"' DISTRIBUTION SYSTEM REFRIGERATION SYSTEM Downstream of the temperature control valves, the hot bleed air which passed through the yawn is joined by that portion of the air which was refrigerated. The hot and cold air are mixed downstream of the valves to become temperature-controlled air. The cabin and cockpit have separate temperature control valves and distribution systems. The cockpit distribution system consists of the ducting from the cockpit temperature con- trol valve, the refrigerated air duct, an air duct check valve, a silencer, and four outlets in the cockpit. There are two controllable side (or shoulder) outlets and two non-controllable foot outlets, one each on the pilot side and the copilot side. The cabin distribution system consists of duct- ing from the cabin temperature control valve, refrigerated air check valve, a silencer, and two baseboard-shaped outlets running practically the entire length of the cabin on both sides. A fluted skirt near the floor level allows the air from the baseboard to enter the compartment. Cabin and cockpit air check valves are in- stalled in the compartment ducting. They allow air to pass only in a forward direction. Should the air attempt to reverse flow, the valves close and prevent backflow. Cabin and cockpit silencers are installed in the "Leung under the floor for noise attenuation. The silencer function is to suppress the air noise from the engine bleed-air ducts. Bleed air which does not bypass the temper- ature control valves is routed into the refrig- eration unit. The refrigeration unit consists of the following major components: • Primary heat exchanger • ACM and ACM overtemperature thermal switch • Secondary heat exchanger • Mixing muff, screen, and bypass duct assembly • Water separator anti-ice valve with as- sociated sensor • Water separator unit • Cooling fan Cooling is accomplished by heat exchangers and an expansion turbine. Dehumidification is accomplished by a mechanical water sepa- rator, which is prevented from icing by means of an anti-ice system. Airflow across the heat exchangers is automatically maintained with a ground cooling fan. Primary Heat Exchangers The primary heat exchangers are the first stage of refrigeration. They use ram air from the dorsal fin ram-air inlet as a coolant. These single-pass heat exchangers are mounted in the tail compartment. FOR TRAINING PURPOSES ONLY 11-9 EFTA01119979 1 G0030001400 PILOT TRAINING MANUAL Air Cycle Machine The air cycle machine (ACM) is an expansion panslon turbine which reduces temperature by the air to perform useful work, and so causes a pressure and temperature drop. The work extracted from the airstream in the turbine section is absorbed by operating a compres- sor wheel, which is directly shafted to the tur- bine wheel, located in a separate chamber on the upstream side of the unit. A large perc age of the work extracted from the airstream by the turbine is used by the compressor wheel. As the compressor wheel is performing work on the upstream air, its pressure and temper- ature are increased. This is called the bootstrap principle, which is actually a pressure recov- ery system used in modern air cycle systems. Secondary Heat Exchangers Heat exchangers are installed adjacent to the primary heat exchangers in the tail compart- ment. These heat exchangers also use ram air from the dorsal fin ram-air inlet as a coolant. Water Separator System Expansion through the cooling turbine reduces discharge temperatures below atem- peratures and forces moisture it to condense. Water Separators The water separators provide a mechanical means of water removal and consist of two sec- tions: the inlet section is a coalescer and makes a few large drops from many small droplets by passing the droplet-laden airstream through a coarse mesh cloth bag while the second section accomplishes the actual water removal. Water extracted from the air is also sprayed into the secondary heat exchanger cooling air inlet to assist in cooling. Flight saiety Water Separator Anti-ice System On a cool, moist day cooling turbine discharge temperatures fall low enough that water is not only condensed but freezes. To Prevent theba of the water separator from becoming cloggedt with ice crystals and restricting the airflow, a water separator anti-ice system is installed. Water Separator Anti-ice Valve This Me is a butterfly-type shutoff adored. ulatiral ve. The unit controls the refriger- ation unit cold air outlet temperature to a minimum of 37°F (nominal) by modulating the flow of compressor inlet air to the anti-ice muff at the turbine discharge. Water Separator Anti-ice Sensor The w ater separator anti-ice sensor isapneu- matte thermostat, installed on the discharge side of the water separator. This thermostat's set to maintain the valve position so 'batik air moving through the water separatoriskld at a temperature of approximately 37°F. The system design is such that maximumuti- lization can be made of refrigeration anode humidification systems regardless of high of low humidity conditions, or high or love.alu• act tude conditions, with the sensor extr control over the valve and the system. Bootstrap Overtemperature Warning System Incorporated on the discharge side of theboot" strap unit compressor section is a 450°Fh.ci: trneorasl, compressor It is the function of this °lic: compressor section. If there w ere no 3irri a. or retarded airflow across the ha excha% rise. As discharge temperature of the boc'i ntill,„ discharge temperaul„nef re Ow completes a circuit to the L/R COOL HOT dsisaprleasyul(tEtihcisAssw)i-tch clo'es at 9jvTug8 11-10 FOR TRAINING PURPOSES ONLY EFTA01119980 GIV/G300/G400 PILOT TRAINING MANUAL An additional function of this warning device is in ground configuration. If the trip temper- ature is reached on the ground, a circuit is completed to the EICAS to alert crewmembers. The same circuit is completed through ground configuration of the nutcracker system to close the air-conditioning shutoff valve of the af- fected pack. NOTE In flight, the switch gives a warning only to crewmembers. On the ground, the switch gives a warning and shuts off the air conditioning of that pack. Ground Air Conditioning Ground air conditioning presents additional re- quirements to the system. On the ground there is no ram air and thus no coolant airflow across the primary and secondary heat exchangers. This airflow must be supplied; otherwise, the refrigeration equipment overheats. In addition there are times when air-conditioning system op- eration must be terminated due to high demands from the bleed-air manifold, such as during en- gine starts. Being a self-supporting aircraft, it must be capable of being air-conditioned using the APU even if the main engines are not oper- ating. Airflow through the system when in ground operation is the same from the bleed-air manifold to the compartment outlets. Cooling Fan A turbofan is installed downstream of the ACM in the dorsal fin ram-air duct. The fan assembly, rigidly fixed to the armature of the ACM, provides airflow across primary and secondary heat exchangers whenever air con- ditioning is in operation. Air for cooling is de- livered through the ram-air inlet in flight and a flapper valve in the refrigeration unit on the ground. All air is then ported overboard. FightsafetY --1,N111 Cooling Air Distribution Dehumidified, refrigerated air from the discharge side of the water separator is ducted forward, the main portion joining that part of the hot air which passed through the temperature control valves to become temperature-controlled air. Also, refrig- erated air from the unit is ducted into one line which serves furnishing-agency-installed eyeball outlets. A check valve is installed in each line to prevent backflow. Provisions are incorporated for the furnishing agency to complete the installation to the cockpit and cabin, the number of eyeball outlets depending on the number of seats installed. The air from the outlets is dehumidified and refrigerated. RAM-AIR VENTILATION SYSTEM In the event of an emergency, the crew can ven- tilate the aircraft by use of ram air scooped in through a dorsal fin ram-air inlet. A line is tapped into the ram-air duct just upstream of the primary heat exchanger. This line is routed to the ram-air check valve and then to the downstream side of the left water separator re- frigerated air duct. If ram-air duct pressure is above refrigerated air duct pressure, the check valve opens and admits ram air to the refrig- erated air line. Airflow moves forward through the cabin duct check valve into the distribu- tion system. The check valve allows airflow to move only from the ram-air duct into the system ducting. In normal operation, with air-conditioning operation, duct pressure is always above ram-air pressure; consequently, the ram-air check valve is held closed, maintaining system integrity. Selection of ram-air ventilation is accomplished using the RAM AIR switch located on the over- head panel. Placing the switch to RAM sup- plies 28 VDC from the essential DC bus to both of the air-conditioning shutoff valves. This en- ergizes the valve solenoids and stops air con- ditioning. As duct pressure drops, ram pressure predominates across the ram-air check valve and allows ram-air ventilation. AIR CONDITIONING FOR TRAINING PURPOSES ONLY EFTA01119981