Chapter 21 Air Conditioning

Transcription

1 Chapter 21 Page Date: 8. December Page 1

2 Table of Contents GENERAL...5 Description...5 Troubleshooting...6 Service and Maintenance...8 Removal / Installation DISTRIBUTION...9 Description Panel Vent Fans...9 Removal (Pilot s Side)...9 Installation (Pilot s Side)...10 Removal (Copilot s Side)...12 Installation (Copilot s Side) PRESSURIZATION CONTROL...15 Description...15 Handling...16 Removal / Installation Cabin Outflow Control Valve Filter...18 Replacement Cabin Outflow Control Valve...18 Removal / Installation Safety Valve...19 Removal / Installation TEMPERATURE CONTROL...20 Description...20 Page 2 21 Page Date: 13. July 2001

3 Figure 21-01a Cabin Air Condition and Pressurization Scheme (SN 03 to 19) Page Date: 13. July Page 3

4 Figure 21 01b Cabin Air Condition and Pressurization Scheme (from SN 20 foll.) Page 4 21 Page Date: 13. July 2001

5 GENERAL Description Refer to Figure 21-01a/b. For ventilation either pressurized or ram air is available. The air source can be selected by the cabin air selection knob located on the middle console controlling the cabin air selection valve. If pressurized air is selected, air is guided from the combustion air intake through an air filter, the turbocharger, the intercooler, a sonic venturi and then either through the cabin cooler or directly through the cabin inflow check valve into the cabin. At the same time ram air is guided from the ventilation air ram intake to the vacuum pumps for cooling. Note If maximum air flow for ventilating is desired it is advisable to select pressurized air. If ram air is selected, air is guided from the ventilation air ram intake through the cabin inflow check valve into the cabin, while pressurized air now feeds the vacuum pumps. SN 03 through 19 Inside the cabin air can be guided to the windshield dispensers for defogging and defrosting and to the legroom dispenser or through the RH armrest channel to the rear, which depends on the position of the windshield defrost flap controlled by the respective knob on the middle console. In the pressure dome area an electric heater and the evaporators of the air conditioning system are installed. The evaporators also work as cabin fans. The air conditioning system including a compressor condenser module located in the tail cone sucks cabin air and blows cool air through hoses to the eyeball vents and the leg room dispenser in the front cockpit area and to the adjustable nozzles in the overhead air channel of the passenger compartment ceiling. SN 20 through 25 From SN 20, the ventilation system has been modified. Instead of the rear overhead air channel, the cooled air is now routed through the LH arm rest duct to the lower LH cockpit section as well as through the RH arm rest duct to the RH cockpit section. The overhead air channel is furnished with a vent fan to feed the adjustable air deflectors with ventilated cabin air. The eyeball vents have been replaced by two independent adjustable air outlets, which are combined with two panel vent fans to re-circulate the cockpit air. Finally, the leg room dispenser has been removed. When the evaporator blowers are operating, either cooled (air condition on) or ventilated (air condition off) air is pressed through both side armrest channels. From the RH evaporator blower, air is led into a duct in the RH armrest to the right cockpit section. From the LH evaporator blower, air is ducted first through the electrical heater in the LH armrest duct. This duct leads through the Page Date: July Page 5

6 cabin door where it is sealed with two oval rubber seals, and finally is routed into the lower LH cockpit section. When the electrical heater is engaged the compressor module is disengaged, and vice versa. From SN 20, operation of the heating, ventilating and air conditioning system implies the following characteristics: (Refer to Section 7, Pilot s Operating Handbook, figures 7-3, 4, 6, 13) 1 The cabin ventilation system, including both evaporator blowers and the overhead air channel vent fan, is controlled by the VENT HI / LO switch in the CABIN area of the left side panel. Both evaporator blowers work with different power settings in low or high mode, whereas overhead air channel fan operation features only one power rate for both switch positions LO / HI. 2 Heating and air conditioning system work exclusively. For either operating the heating or the air conditioning, the ventilation system must run in high mode simultaneously (VENT switch to position HI). SN 26 following The LH duct ends in the LH armrest behind the switch/breaker panel. The other system components remain unchanged. Troubleshooting Complaint Possible Cause Remedy No or inadequate pressurization Incorrect pressurization or pressurization rate control Excessive cabin leakage Excessive door seal leakage Excessive emergency exit seal leakage Dump solenoid energized Controller failure Pressurization system inactive Control valve failure Safety valve failure Pressurization system inactive Control valve static reference blocked Control valve filter blocked Controller defective Identify and seal Replace door seal Replace emergency exit seal Check dump switch and squat switch Replace controller Switch pressurization system ON Replace control valve Replace safety valve Switch pressurization system ON Clean static reference connection Replace filter Replace controller Page 6 21 Page Date: July

7 Complaint Possible Cause Remedy Incorrect pressurization or pressurization rate control Pressure differential exceeding 5.5 psi No dump Erroneous CAB PRESS warning Control valve defective Control valve static reference blocked Control valve differential failure Pressurization system inactive Squat switch setting incorrect Safety valve static reference blocked Dump switch defective Squat switch defective Safety valve solenoid failure Safety valve blind plug at vacuum port not installed Differential pressure switch (5.65 psig) defective Absolute pressure switch (10,000 ft) defective Replace control valve Clean static reference connection Replace control valve Switch pressurization system ON Correct squat switch setting Clean static reference connection Replace dump switch Replace squat switch Replace safety valve Install blind plug Replace differential pressure switch Replace absolute pressure switch Page Date: July Page 7

8 Service and Maintenance Servicing of the air-conditioning unit shall be performed by an approved airconditioning service station, only R-134a type refrigerant must be used. The air-conditioning compressor condenser module is equipped with conventional evacuating and charging connections. After new system plumbing installation, component replacement or line or hose rupture, a leak check is required, see General Operating, Servicing and Maintenance Manual for Airborne R-134a Air-conditioning Systems for leak check and general charging procedures. Refer to General Operating, Servicing and Maintenance Manual for Airborne R-134a Air-conditioning Systems for component maintenance procedures.. Access to the compressor condenser module is gained through the tailcone access hatch. Charging quantity of the installation is kg +/ kg, proper charging can be verified at the sight glass on the receiver dryer. With the system fully charged and operating, observe the suction and discharge pressures. Typical values at various ambient temperatures, with hot cabins are shown below: OAT ( C) Suction pressure (psig) Discharge pressure (psig) Removal / Installation For removal and installation of air-conditioning, heating or temperature control system components, contact EXTRA Flugzeugbau GmbH. Page 8 21 Page Date: 13. July 2001

9 DISTRIBUTION Description Valid for Serial - No. 20 following For better ventilation in the forward cabin section two vent fans (Micronel type D603L-024KA-3) are installed in the LH and RH side of the instrument panel. Each vent fan sucks air through a composite tube from the lower side of the panel shelf. On the blow side each vent fan is connected to a vent grid, which can be adjusted to either direct or shut off the air flow. Two jiggle switches (marked 0/1), placed on the instrument panel near the resp. air outlet, control the vent fans. The electric fan motors are protected by a 1A - fuse each Panel Vent Fans Valid for Serial - No. 20 following CAUTION With some installations, it might not be required to remove the main panel completely, depending on individual wire and hose length. Take care not to damage instrument wiring and gyro air hoses. Removal (Pilot s Side) Main Panel Removal 1 Remove 8 Phillips screws around left main panel 2 Remove 4 Phillips screws securing EHSI ED to panel 3 Remove 4 Phillips screws securing EADI ED to panel 4 Slightly swivel down left main panel Take care not to damage flexible hoses and electrical wiring 5 Disconnect illumination wires on instruments without D-Sub-Connections 6 Disconnect D-Sub-Connection on Warning Panel 7 Disconnect D-Sub-Connection on Fuel Flow Indicator 8 Disconnect electrical wiring on OAT Indicator 9 Disconnect DME Hold Switch Page Date: 13. July Page 9

10 10 Disconnect electrical wiring on Turn Coordinator 11 Disconnect electrical wiring on Slaving Control KA - 51 B 12 Disconnect wiring from Amperemeter (prop de-ice) Molex plug 13 Unscrew flexible hose on Manifold / Fuel Pressure Gauge 14 Pull off pitot and static hoses from Airspeed Indicator 15 Pull off static hose to Altimeter at T-fitting next to Altimeter 16 Pull off static hose to Vertical Speed Indicator at T-fitting next to Vertical Speed Indicator 17 Remove main panel completely Vent Fan Removal 18 Carefully remove vent grid from panel Use a lever to pull out four guide lugs at the edges 19 Remove composite tube from vent fan back side 20 Cut off two electrical wires about 5 10 inches from fan connection or de-solder wires from fan connection Loosen clamp Sign connection 21 Loosen 4 Allen bolts and nuts securing fan to LH panel corner 22 Remove vent fan inclined backwards Installation (Pilot s Side) Vent Fan Installation 1 Move fan to back side of LH panel corner 2 Install 4 Allen bolts and nuts securing fan to panel 3 Re-solder electrical wires to fan connection Page Page Date: 13. July 2001

11 4 Lead composite tube from underside of instrument shelf to vent fan back side. Install tube with clamp. 5 Snap vent grid into panel Main Panel Installation 6 Move left main panel in reach of connections 7 Connect D-Sub-Connections on Warning Panel 8 Connect D-Sub-Connections on Fuel Flow Indicator 9 Connect electrical wiring to OAT Indicator 10 Connect DME Hold Switch 11 Connect electrical wiring to Turn Coordinator 12 Connect electrical wiring to Slaving Control KA - 51 B 13 Connect Molex - plug to Amperemeter (prop de-ice) 14 Connect illumination wires to instruments without D-Sub-Connections 15 Connect flexible hose to Manifold / Fuel Pressure Gauge 16 Connect pitot and static hoses to Airspeed Indicator 17 Connect Altimeter static hose to T-fitting 18 Connect Vertical Speed Indicator static hose to T-fitting 19 Insert panel into instrument shelf Take care not to damage flexible hoses and electrical wiring 20 Re-install Phillips screws to panel 21 Re-install Phillips screws to ED Re-install Phillips screws to ED Page Date: 13. July Page 11

12 Removal (Copilot s Side) 1 Remove 8 Phillips screws around right main panel 2 Slightly swivel down right main panel Take care not to damage flexible hoses and electrical wiring 3 Remove two 37-pin-connections from Annunciator Panel 4 Remove 30-pin-connection from KNI-204 VOR/LOC and Glide Slope Indicator 5 Pull off static and pitot hoses from Airspeed Indicator 6 Disconnect wiring from Airspeed Indicator Molex plug 7 Pull off static hose from Altimeter 8 Disconnect wiring from Altimeter Molex plug 9 Remove Vac., Gage and Air Inlet hoses from Sigma Tek 5000 Vacuum Horizon 10 Disconnect wiring from Sigma Tek 5000 Vacuum Horizon Molex plug 11 Remove Vac., Gage and Air Inlet hoses from Sigma Tek 4000 Directional Gyro 12 Disconnect wiring from Sigma Tek 4000 Directional Gyro Molex plug 13 Remove 3 single pin connections from Coolant Temperature Gage 14 Remove 4 single pin connections from CHT/EGT Gage 15 Remove 5 single pin connections from Oil Temperature / Oil Pressure Gage 16 Remove 2 single pin connections from TIT Gage 17 Remove 2 single plugs and 1 triple plug from LH Fuel Quantity Gage 18 Remove 2 single plugs and 1 triple plug from RH Fuel Quantity Gage Page Page Date: 13. July 2001

13 19 Remove 2 screwed cable clamps (+, -) from Ammeter 20 Remove 2 screwed cable clamps (+, -) from Voltmeter 21 Remove 4 air hoses Vent, Vac, R, L from Dual Suction Gage 22 Remove main panel completely Vent Fan Removal 23 Carefully remove vent grid from panel Use a lever to pull out four guide lugs at the edges 24 Remove composite tube from vent fan back side 25 Cut off two electrical wires about 5 10 inches from fan connection or de-solder wires from fan connection Loosen clamp Sign connection 26 Loosen 4 Allen bolts and nuts securing fan to LH panel corner 27 Remove vent fan inclined backwards Installation (Copilot s Side) Vent Fan Installation 1 Position fan to back side of RH panel corner 2 Install 4 Allen bolts and nuts securing fan to panel 3 Re-solder electrical wires to fan connection 4 Lead composite tube from underside of instrument shelf to vent fan back side. Install tube with clamp. 5 Snap vent grid into panel Main Panel Installation 6 Move right main panel in reach of instrument connections 7 Screw cable clamps (+,-) to Voltmeter 8 Screw cable clamps (+,-) to Ammeter Page Date: 13. July Page 13

14 9 Install single plugs and triple plug to LH Fuel Quantity Gage 10 Install single plugs and triple plug to RH Fuel Quantity Gage 11 Install 2 single pin connections to TIT Gage 12 Install 5 single pin connections to Oil Temperature / Oil Pressure Gage 13 Install 4 single pin connections to CHT / EGT Gage 14 Install 3 single pin connections to Coolant Temperature Gage 15 Connect Molex plug to Sigma Tek 4000 Directional Gyro 16 Install Vac., Gage and Air Inlet hoses to Sigma Tek 4000 Directional Gyro 17 Connect Molex plug to Sigma Tek 5000 Vacuum Horizon 18 Install Vac., Gage and Air Inlet hoses to Sigma Tek 5000 Vacuum Horizon 19 Install 4 air hoses Vent, Vac, R, L to Dual Suction Gage 20 Connect static hose with Altimeter 21 Connect Molex plug to Altimeter 22 Connect static and pitot hoses with Airspeed Indicator 23 Connect Molex plug to Airspeed Indicator 24 Install 30-pin-connection to KNI-204 VOR/LOC and Glide Slope Indicator 25 Install two 37-pin-connections to Annunciator Panel 26 Insert panel into instrument shelf Take care not to damage flexible hoses and electrical wiring 27 Re-install Phillips screws to panel Page Page Date: 13. July 2001

15 PRESSURIZATION CONTROL Maintenance Manual and Illustrated Parts Catalogue Description The system consists of the engine turbocharger, a sonic venturi (flow limiter), a cabin control outflow valve, an unregulated safety valve, the cabin pressurization switch, the cabin pressure controller, a dump safety switch, the landing gear squat switch, and two indicators, one for cabin altitude and differential pressure and one for cabin rate-of-climb. Pressurization air is supplied from the engine turbocharger through the sonic venturi and then through a check valve into the cabin. Adequate flow to maintain pressurization up to the maximum differential pressure of 5.5 PSI is provided by the engine at normal power setting. Power changes should be made smoothly to prevent sudden changes in pressurization air inflow resulting in cabin pressure transients. The airplane may be operated in either the pressurized or depressurized mode. The mode selection is made with the cabin pressurization switch, which either opens the safety valve for depressurized mode, or closes the safety valve and thus activating the cabin control outflow valve for pressurized mode, on condition that pressurized air is selected on the cabin air knob and the dump safety switch is in OFF-position. Mode operation should be selected prior to takeoff. If a change from pressurized to depressurized mode must be made while airborne, depressurize the cabin following the procedure given below before turning the dump switch as otherwise a rapid decompression occurs, which would cause discomfort to the passengers. When changing from unpressurized to pressurized mode, the cabin altitude rate of change will be limited by the pressurization controller. The valves are also opened by the landing gear squat switch assuring depressurized mode when aircraft is on ground to avoid bursting the cabin door due to cabin pressure when opening. However this is only a safety device: landing in pressurized mode is prohibited! In the pressurized mode cabin pressure is regulated by the cabin control outflow valve allowing air to exhaust either to the pressure level preselected by the cabin pressure controller or to maximum differential pressure level. Setting the center dial (identified as Flight Level ) of the cabin pressure controller will suggest the system being at a certain flight altitude. So the system will maintain the corresponding cabin altitude (about 5.5 PSI above static pressure of flight level) or reach it with the rate set by the rate control knob located on the lower left corner of the pressurization controller. Only in case of maximum differential pressure is reached or flight level is below the selected cabin altitude, cabin altitude changes with the same rate the flight altitude does. In case of failure of the cabin outflow control valve the safety valve will open at a differential pressure of slightly above 5.5 PSI to avoid structure damage. Page Date: 13. July Page 15

16 Handling Use the cabin pressure controller as follows. Also refer to the sample chart (Figure 21-02). 1 Activate the pressurization controller by turning on the cabin pressurization switch. Make sure that the dump switch is off and the pressurized cabin air is selected. 2 Set the published official airport altitude (such as shown on flight charts) under the index arrow by turning the center control knob. 3 Turn the index arrow of the rate control knob (lower left corner of the control) to the 12 o clock position (approx. 500 fpm). These steps set the system to pressurize at approximately 700 feet above the runway after takeoff. The system will hold this cabin altitude until the maximum differential altitude is reached (see Cabin Altitude with minimum Flight Level Setting line of Figure 21-02) or a different cabin pressure is selected. 4 After having cleared the airport area and established the climb and being on course to the destination (see a on Figure 21-02), select the flight level corresponding to the intended cruise altitude in the center dial and align that with the index arrow. This alignment also indicates the approximate cabin altitude (within approx. 700 feet) at the index on the larger numbers marked Airport Alt.. 5 Increase or decrease the rate at which the cabin changes altitude for the best comfort level from normally 500 fpm by turning the rate knob counter clockwise for decreasing or clockwise for increasing the rate. Usually it is the best method to set the rate to reach the changed cabin pressure (referenced from the Airport Alt. ) slightly ahead of reaching the cruising altitude (550 fpm in the sample of Figure 21-02). This selected altitude will be maintained until the aircraft changes altitude sufficiently to reach the max. differential pressure or descends sufficiently to go below the selected airport altitude. 6 When the aircraft reaches the proximity of the destination and starts to descent (see b on Figure 21-02), set the selector knob to the published airport altitude. 7 Set the rate so that the selected airport altitude is reached in the cabin prior to descending to that altitude (650 fpm in the sample of Figure 21-02). When approaching the runway, the pressurization will cease approximately 700 feet above the landing prior to landing. Should any slight pressure remain, the remainder will dump when the squat switch closes. However, this is an additionally safety device, because landing with cabin pressurized is not allowed. CAUTION If pressurization mode shall be finished during flight, follow the procedure above, setting the airport altitude equal to the momentary flight altitude. Switch to the depressurized mode not before the selected airport altitude is reached. Page Page Date: 13. July 2001

17 Figure Cabin Pressurization Sample Chart Page Date: 13. July Page 17

18 Removal / Installation For removal and installation of pressurization system components, contact EXTRA Flugzeugbau GmbH Cabin Outflow Control Valve Filter Replacement 1 Gain access to the inner side of the rear pressure bulkhead by removing the aft cabin liner 2 Loosen the filter retention screw on the control outflow valve housing until the filter flange is free to rotate. It is not necessary to remove the screw entirely. 3 Rotate the filter until the flat on the filter clears the screw head. 4 Remove the filter cartridge and replace with new one. 5 Rotate the filter so filter flange is captured by the screw head. 6 Tighten filter retaining screw Cabin Outflow Control Valve The valve is attached to the LH side of the pressure dome. Removal / Installation Removal 1 Remove upper half of rear baggage compartment wall Machine screws AN Remove tail cone access panel on LH fuselage side 3 Remove valve flange from pressure dome 8 stop nuts MS AN3 with washers AN960 10L (3/8 inch.) Page Page Date: 13. July 2001

19 4 Remove 2 overflow tubes 9/16 fitting; retain with 11/16 wrench at pressure dome fitting 5 Lift up valve from pressure dome Installation Install in reverse sequence of removal Safety Valve The valve is attached to the RH side of the pressure dome. Removal / Installation Removal 1 Remove upper half of rear baggage compartment wall Machine screws AN Remove tail cone access panel on LH fuselage side 3 Remove battery Refer to Ch Remove valve flange from pressure dome 8 stop nuts MS AN3 with washers AN960 10L (3/8 inch.) 4 Remove 2 overflow tubes 9/16 fitting; retain with 11/16 wrench at pressure dome fitting 5 Lift up valve from pressure dome Installation Install in reverse sequence of removal NOTE Verify that blind plug at vacuum port is installed correctly. With installed valve, the vacuum port is accessible behind the rear baggage compartment wall. Page Date: 13. July Page 19

20 TEMPERATURE CONTROL Description If pressurized air is selected the temperature mainly can be regulated by means of the cabin cooler bypass valve controlled by the cabin temperature knob located on the middle console. Additional regulating is possible by either activating the electric heater or by switching on or off the air conditioning system and changing the operation mode of the cabin ventilation. Note The heater and the air conditioning system operate only if cabin ventilation is running at least in low mode. If ram air is selected the cabin temperature knob has no function. Page Page Date: 13. July 2001