Air conditions & pressurization part 2
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Air conditions & pressurization part 2

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    Air conditions & pressurization part 2 Air conditions & pressurization part 2 Presentation Transcript

    • MENU PRINCIPAL
    • THIS SECTION BEGINS WITH A BRIEF OVERVIEW OF THE PURPOSE AND MAJORCOMPONENTS OF THE PRESSURIZATION SYSTEM. FOLLOWING THE OVERVIEW, WE WILLDISCUSS THE CONTROLS AND INDICATORS USED TO OPERATE THE SYSTEM.MENU PRINCIPAL
    • THE PRESSURIZATION SYSTEM PROVIDES COMFORTABLE CABIN ALTITUDES AT ALLFLIGHT LEVELS, AND ALSO PROVIDES COMFORTABLE CABIN RATE OF CHANGES DURINGCLIMB AND DESCENT.MENU PRINCIPAL
    • THE PRESSURIZATION CONTROLLER IS THE HEART OF THE SYSTEM. (pause2) ITREGULATES THE FLOW OF CONDITIONED AIR FROM THE AIRPLANE THROUGH A MAINOUTFLOW VALVE. THE MAIN OUTFLOW VALVE CONTROLS A FORWARD OUTFLOW VALVETO PROVIDE PRECISION CONTROL OF AIRPLANE PRESSURIZATION. LETS TAKE A CLOSERLOOK AT HOW CABIN AIR EXHAUSTS THROUGH THE OUTFLOW VALVES.MENU PRINCIPAL
    • THE MAIN OUTFLOW VALVE REGULATES THE FLOW OF AIR FROM AROUND THE AFTCARGO COMPARTMENT. WARM AIR FROM THE PASSENGER CABIN PASSES AROUND THECARGO COMPARTMENT TO HEAT IT, AND IS EXHAUSTED OVERBOARD THROUGH THISVALVE.MENU PRINCIPAL
    • DURING OPERATIONS AT LOW DIFFERENTIAL PRESSURE, AIR FLOW FROM THE EQUIPMENTCOOLING SYSTEM IS DISCHARGED THROUGH A FLOW CONTROL VALVE. THE AIR IS THENEXHAUSTED OVERBOARD.MENU PRINCIPAL
    • WHEN THE DIFFERENTIAL PRESSURE IS MORE THAN 2 POINT 5 PSI, THE FLOW CONTROLVALVE IS FORCED CLOSED. THE AIR FLOW IS THEN DIRECTED AROUND THE FORWARDCARGO COMPARTMENT TO PROVIDE HEATING.MENU PRINCIPAL
    • THE AIR PASSES AROUND THE FORWARD CARGO COMPARTMENT AND IS DISCHARGEDOVERBOARD THROUGH THE FORWARD OUTFLOW VALVE.MENU PRINCIPAL
    • TWO POSITIVE PRESSURE RELIEF VALVES INSURE THAT THE MAXIMUM DIFFERENTIALPRESSURE OF 8 POINT SIX FIVE PSI IS NOT EXCEEDED. (pause3) A NEGATIVE PRESSURERELIEF VALVE PREVENTS THE OUTSIDE PRESSURE FROM EXCEEDING CABIN PRESSUREBY APPROXIMATELY 1 PSI.MENU PRINCIPAL
    • THE PRESSURIZATION CONTROLLER HAS THREE MODES OF OPERATION, AUTOMATIC,STANDBY, AND MANUAL. (pause2) THE AUTOMATIC MODE IS THE NORMAL OPERATINGMODE. IT POSITIONS THE MAIN OUTFLOW VALVE WITH AN AC MOTOR. (pause2) STANDBY ISA BACKUP FOR THE AUTOMATIC MODE. IT USES A DC MOTOR. (pause2) THE MANUAL MODEUSES EITHER THE AC OR DC MOTOR TO PROVIDE CONTROL OF THE MAIN OUTFLOWVALVE.MENU PRINCIPAL
    • STATIC PRESSURE IS ONE OF THE INPUTS TO THE AUTOMATIC MODE. (pause2) IT IS SUPPLIEDDIRECTLY FROM THE CAPTAINS AUXILIARY STATIC SYSTEM. (pause2) THE STANDBY MODERECEIVES A STATIC PRESSURE SIGNAL FROM THE AIR DATA COMPUTER, OR ADC. (pause2) THISCOMPUTER ELECTRONICALLY SUPPLIES A REFERENCE TO THE STANDBY MODE.THE MANUAL MODE HAS NO STATIC PRESSURE INPUT. A CABIN PRESSURE SENSOR PROVIDES ACABIN ALTITUDE REFERENCE TO THE AUTOMATIC AND STANDBY MODES.A BAROMETRIC SET KNOB PROVIDES CORRECTIONS TO THE SYSTEM FOR LOCAL CONDITIONS.MENU PRINCIPAL
    • THE ANSWER IS C.MENU PRINCIPAL
    • THE AUTOMATIC MODE OF THE CONTROLLER RECEIVES INPUTS FROM A BAROMETRIC SETKNOB. (pause3) NOW LETS LOOK AT THE OPERATION OF THE AUTOMATIC MODE.MENU PRINCIPAL
    • THE AUTOMATIC MODE REQUIRES INPUTS BY THE FLIGHT CREW: THE PLANNED FLIGHTALTITUDE AND THE LANDING AIRPORT ELEVATION. THE CONTROLLER COMPARES THESEINPUTS AND DETERMINES THE DIFFERENTIAL PRESSURE REQUIRED TO PRODUCE THEMOST DESIRABLE CABIN ALTITUDE. (pause3) THE CONTROLLER SELECTS DIFFERENTIALPRESSURE IN A RANGE FROM ZERO TO 7 POINT 8 PSI.MENU PRINCIPAL
    • AS LONG AS THE FLIGHT ALTITUDE IS LOW ENOUGH TO MAINTAIN THE DIFFERENTIALPRESSURE IN THE ZERO TO 7 POINT 8 PSI RANGE, THE CONTROLLER WILL MAINTAINCABIN ALTITUDE TO APPROXIMATELY LANDING AIRPORT ELEVATION.MENU PRINCIPAL
    • WHEN HIGHER FLIGHT ALTITUDES ARE SELECTED, THE CONTROLLER WILL MAINTAIN THE7 POINT 8 DIFFERENTIAL PRESSURE BY INCREASING THE CABIN ALTITUDE.MENU PRINCIPAL
    • PRIOR TO TAKEOFF, THE CONTROLLER PRESSURIZES THE CABIN TO TWO HUNDRED FEETBELOW THE AIRPORT ELEVATION. THIS DECREASES THE MAGNITUDE OF A PRESSUREBUMP, AT LIFTOFF.MENU PRINCIPAL
    • IF THE AIRPLANE LEVELS []OFF IN THE CLIMB SEGMENT, THE CABIN ALTITUDE LEVELS[]OFF. WHEN THE AIRPLANE RESUMES CLIMB, THE CABIN RESUMES CLIMB UNTIL ITREACHES 7 POINT 8 PSI.MENU PRINCIPAL
    • DURING DESCENT, THE PRESSURE CONTROLLER REDUCES CABIN ALTITUDE AT A FIXEDRATE OF 450 FEET PER MINUTE. IF THE AIRPLANE LEVELS []OFF, THE CABIN levels []off. TOAVOID A PRESSURE BUMP ON LANDING, THE CABIN IS PRESSURIZED TO 300 FEET BELOWTHE LANDING AIRPORT ELEVATION. THIS PRESSURE IS DECREASED TO 200 FEET ONTOUCHDOWN.MENU PRINCIPAL
    • AT LOWER FLIGHT ALTITUDES, THE CONTROLLER COMPUTES THE LANDING ELEVATION,MINUS three HUNDRED FEET, TO DETERMINE THE MOST DESIRABLE CABIN CRUISEALTITUDE. FOR EXAMPLE, AT A FLIGHT ALTITUDE OF 10,000 FEET, AND A LANDINGELEVATION OF SEA LEVEL, THE DIFFERENTIAL PRESSURE IS LESS THAN 7 POINT 8 PSI.CABIN ALTITUDE IS 300 HUNDRED FEET BELOW SEA LEVEL FOR THE ENTIRE FLIGHT.MENU PRINCIPAL
    • A PROFILE OF THIS FLIGHT SHOWS HOW THE CONTROLLER OPERATES. PRIOR TOTAKEOFF, THE CABIN IS PRESSURIZED TO A MINUS 200 FEET TO AVOID THE PRESSUREBUMP.AFTER TAKEOFF, AS THE AIRPLANE CLIMBS TO 10,000 FEET, THE CABIN ALTITUDEDESCENDS TO THE LANDING AIRPORT ELEVATION, (pause2) MINUS 300 FEET. THEDIFFERENTIAL PRESSURE IS LESS THAN 7 POINT 8, SO THE MINUS 300 FEET IS THE CABINALTITUDE FOR THE ENTIRE FLIGHT.MENU PRINCIPAL
    • LETS CONSIDER A FLIGHT ALTITUDE OF 18,000 FEET, AND A LANDING ELEVATION OF 700FEET.MENU PRINCIPAL
    • SINCE THE DIFFERENTIAL PRESSURE IS STILL LESS THAN 7 POINT 8 PSI, THE CONTROLLERCOMPUTES THE LANDING ELEVATION MINUS 300 FEET, TO DETERMINE A CABIN ALTITUDEOF 400 FEET ABOVE SEA LEVEL FOR THE ENTIRE FLIGHT. (pause3) THE DEPARTUREAIRPORT ELEVATION HAS NO AFFECT ON THE OPERATION OF THE PRESSURECONTROLLER.MENU PRINCIPAL
    • IF FLIGHT ALTITUDES ARE SCHEDULED ABOVE 19,500 FEET, WITH A LANDING ELEVATIONOF SEA LEVEL, THE CONTROLLER WILL OPERATE AT A PRESSURE DIFFERENTIAL OF 7POINT 8 PSI. THE CONTROLLER WILL SCHEDULE A CABIN ALTITUDE PROPORTIONAL TOTHE FLIGHT ALTITUDE, AND REACH A DIFFERENTIAL PRESSURE OF 7 POINT 8 PSI BY THETIME THE AIRPLANE REACHES THE PRESELECTED FLIGHT ALTITUDE.MENU PRINCIPAL
    • WITH A FLIGHT ALTITUDE OF 37,000 FEET, AND A LANDING AIRPORT ELEVATION OF SEALEVEL, THE CONTROLLER DETERMINES THAT THE DIFFERENTIAL PRESSURE WILL BE 7POINT 8 PSI. AS THE AIRPLANE CLIMBS TO 37,000 FEET, THE CABIN CLIMBSPROPORTIONALLY TO THE AIRPLANE. AS THE AIRPLANE levels []off, THE CABIN REACHESTHE 7 POINT 8 PSI PRESSURE DIFFERENTIAL. IN THIS SITUATION, THE CABIN ALTITUDE WILLCLIMB TO 8,000 FEET.MENU PRINCIPAL
    • IN SUMMARY, THE CONTROLLER WILL ALWAYS PROGRAM THE CABIN TO THE LANDINGAIRPORT ELEVATION MINUS 300 FEET, UNLESS A HIGHER FLIGHT ALTITUDE REQUIRES A 7POINT 8 DIFFERENTIAL PRESSURE.MENU PRINCIPAL
    • B IS THE CORRECT ANSWER.MENU PRINCIPAL
    • WHEN FLIGHT ALTITUDES ARE 19,500 FEET OR BELOW, CABIN ALTITUDE WILL BE LANDINGAIRPORT ELEVATION MINUS 300 FEET.MENU PRINCIPAL
    • DURING CRUISE, AIRPLANE ALTITUDE CAN VARY UP TO 2,000 FEET WHILE CABIN ALTITUDEIS HELD CONSTANT. THIS PROVIDES A CONSTANT CABIN ALTITUDE DURING TURBULENCE.HOWEVER, IF THE AIRPLANE BEGINS AN UNSCHEDULED CLIMB, THE CABIN ALTITUDE WILLONLY HOLD CONSTANT UNTIL A DIFFERENTIAL PRESSURE OF 7 POINT 9 PSI IS REACHED.WHEN THIS PRESSURE IS REACHED, THE CABIN ALTITUDE WILL CLIMB AT ABOUT 500 FEETPER MINUTE, THE MAXIMUM RATE ALLOWED BY THE AUTO CONTROLLER.MENU PRINCIPAL
    • IF THE AIRPLANE CONTINUES THE UNSCHEDULED CLIMB, DIFFERENTIAL PRESSURE WILL INCREASEBECAUSE THE AIRPLANE CLIMBS AT A GREATER RATE THAN THE CABIN. IF THE DIFFERENTIALPRESSURE REACHES 8 POINT SIX FIVE PSI, THE POSITIVE PRESSURE RELIEF VALVES OPEN, ANDTHE CABIN WILL CLIMB WITH THE AIRPLANE. ONCE THE AIRPLANE levels []off, THE CABIN RATE OFCLIMB DECREASES TO THE MAXIMUM RATE ALLOWED BY THE AUTO CONTROLLER. THE CABIN WILLLEVEL [`]OFF AT A DIFFERENTIAL PRESSURE OF SEVEN POINT NINE PSI. REMEMBER, DURING ANUNSCHEDULED CLIMB, CABIN ALTITUDE WILL ONLY HOLD CONSTANT UP TO A PRESSURE OF SEVENPOINT NINE PSI. TAKE A FEW MINUTES TO REVIEW THIS SLIDE.MENU PRINCIPAL
    • LETS LOOK AT THE CONTROLS AND INDICATORS OF THE PRESSURIZATION SYSTEM. THEFORWARD OUTFLOW CLOSED LIGHT ILLUMINATES WHEN THE VALVE IS CLOSED.NORMALLY, THE VALVE IS OPEN AND THE LIGHT IS EXTINGUISHED. LOCATE THIS LIGHT ONYOUR PANEL.MENU PRINCIPAL
    • LETS MOVE DOWN TO THE PRESSURIZATION PANEL.MENU PRINCIPAL
    • THE PRESSURIZATION PANEL IS LOCATED ON THE LOWER RIGHT HAND SIDE OF THEFORWARD OVERHEAD PANEL. LOCATE IT ON YOUR PANEL.MENU PRINCIPAL
    • ARROW NUMBER ONE SHOWS THE DIFFERENTIAL PRESSURE INDICATOR, WHICH HAS TWO SCALES.THE OUTER SCALE INDICATES DIFFERENTIAL PRESSURE FROM ZERO TO TEN PSI.THE INNER SCALE DISPLAYS THE CABIN ALTITUDE. (pause3) THE CABIN CLIMB INDICATOR DISPLAYSTHE CABIN RATE OF CLIMB OR DESCENT FROM ZERO TO 4,000 FEET PER MINUTE.THE CONTROLLER IS DESIGNED TO OPERATE IN SEA LEVEL FEET PER MINUTE. THE INDICATOR MAYDISPLAY A RATE GREATER THAN 450 FEET PER MINUTE, DUE TO THE CHANGE IN AIR DENSITY ATALTITUDE. (pause3) THE ALTITUDE HORN CUTOUT SWITCH SILENCES AN INTERMITTENT WARNINGHORN WHICH SOUNDS IF THE CABIN ALTITUDE EXCEEDS 10,000 FEET.MENU PRINCIPAL
    • LETS EXAMINE THE COCKPIT CONTROLS AND INDICATORS FOR THE AUTOMATIC MODE OFOPERATION. THE MODE SELECTOR IS A FIVE POSITION SWITCH. FOR NORMALOPERATION, THE MODE SELECTOR IS POSITIONED TO AUTO.MENU PRINCIPAL
    • THE DESIRED FLIGHT ALTITUDE IS SET BY PUSHING AND ROTATING THE FLIGHT ALTITUDECONTROL KNOB, UNTIL THE DESIRED NUMBERS APPEAR IN THE WINDOW. FLIGHTALTITUDES MAY BE SET FROM ZERO TO 40,000 FEET. (pause3) LANDING ELEVATION IS SETBY ROTATING THE LAND ALTITUDE CONTROL KNOBS. ROTATE THE OUTER KNOB FOR1,000 FOOT INCREMENTS AND THE INNER KNOB FOR 10 FOOT INCREMENTS. LANDING MAYBE SET FROM MINUS 990 FEET, TO PLUS 13,990 FEET.MENU PRINCIPAL
    • IN THE AUTO MODE, THE FLIGHT GROUND SWITCH CONTROLS THE OUTFLOW VALVE,THROUGH THE LANDING GEAR SAFETY SWITCH. (pause2) DURING GROUND OPERATION,THE GROUND POSITION OPENS THE OUTFLOW VALVE. (pause3) AFTER LANDING,SELECTING THE GROUND POSITION, DEPRESSURIZES THE AIRPLANE AT A RATEPROGRAMMED FOR PASSENGER COMFORT. (pause4) NOW LETS LOOK AT THE FLIGHTPOSITION.MENU PRINCIPAL
    • ON THE GROUND, THE FLIGHT POSITION SIGNALS THE CONTROLLER TO POSITION THEOUTFLOW VALVE PARTIALLY CLOSED. THIS PRESSURIZES THE CABIN TO APPROXIMATELYPOINT ONE PSI DIFFERENTIAL, WHICH IS APPROXIMATELY 200 FEET BELOW THE TAKEOFFFIELD ELEVATION. THIS PRESSURE INCREASE IS REFLECTED ON THE CABINDIFFERENTIAL PRESSURE INDICATOR, AND THE PRESSURE BUMP DURING LIFTOFF ISMINIMIZED (pause2) IN CASE AN EMERGENCY EVACUATION IS NECESSARY, THISPRESSURE WILL NOT PREVENT PASSENGER CABIN DOOR OPERATION.MENU PRINCIPAL
    • THE CORRECT ANSWER IS B.MENU PRINCIPAL
    • THE GROUND POSITION DEPRESSURIZES THE AIRPLANE ONLY WHEN THE AIRPLANE IS ONTHE GROUND. PLACING THE SWITCH TO THE FLIGHT POSITION PRESSURIZES THEAIRPLANE BEFORE TAKEOFF. IF THE SWITCH IS INADVERTENTLY LEFT IN THE GROUNDPOSITION, THE AIRPLANE WILL PRESSURIZE AT A NORMAL RATE AFTER TAKEOFF, BUTTHERE MAY BE A SLIGHT PRESSURE BUMP WHICH COULD CAUSE MINOR PASSENGERDISCOMFORT.MENU PRINCIPAL
    • PLEASE GO ON TO THE NEXT PART OF AIR CONDITIONING AND PRESSURIZATION.MENU PRINCIPALRETURN TO MENU