Fire Protection.docx

2A-26-10: General Fire Protection The Fire Protection system provides the means for detection of smoke, fire and overheat conditions in various parts of the aircraft. The system alerts the crew of engine and nacelle fire, Auxiliary Power Unit (APU) compartment fire, equipment area overheats condit...

2A-26-10: General Fire Protection The Fire Protection system provides the means for detection of smoke, fire and overheat conditions in various parts of the aircraft. The system alerts the crew of engine and nacelle fire, Auxiliary Power Unit (APU) compartment fire, equipment area overheats condition and smoke detection in the baggage compartment. The fire extinguishing system provides for the elimination of fire in the engine core, engine nacelle and APU compartment and portable fire extinguishers for fire in other areas. If a fire is detected, the system sensors alert the flight crew to perform procedures to extinguish the fire by manually directing the discharge of the contents of onboard fire extinguishers. After a fire or overheat condition in the aircraft interior has been eliminated, any remaining smoke can be evacuated overboard through a dedicated valve that vents into the wing-to-body fairing. The system also provides for crew-activated discharge of fire extinguishing agent (Halon 1301) to either Powerplant nacelle (simultaneously to Zones 1 and 2) or the APU compartment, in response to an Engine or APU Fire Crew Advisory System (CAS) message. The Fire Protection system is divided into the following subsystems: 2A-26-20: Engine and Auxiliary Power Unit (APU) Fire and Overheat Detection and Warning System 2A-26-30: Engine and APU Fire Extinguishers 2A-26-40: Aircraft Interior Overheat and Smoke Detection, Smoke Evacuation, and Portable and Fixed Fire Extinguishers Figure 1. Fire Extinguishing System Diagram FIRE EXT DISCHG FI (P TIL-033849A 2A-26-20: Engine and Auxiliary Power Unit (APU) Fire and Overheat Detection and Warning System General Description: The aircraft Powerplant and APU Fire Protection System provides means for detecting and alerting the crew of an overheat or fire condition within the BR725 powerplant nacelle, the adjacent pylon area and the Auxiliary Power Unit (APU) enclosure. The system also provides for crew-activated discharge of fire extinguishing agent (Halon 1301) to either powerplant nacelle (simultaneously to Zones 1 and 2) or the APU compartment, in response to a (warning) or (warning) CAS message. Each aircraft engine is equipped with dual-loop fire detectors placed in critical engine areas to sense heat levels associated with fire. The engine hot bleed air ducting is also monitored for leaks by thermal switches set at predetermined temperatures to signal overheat conditions. The APU enclosure is monitored by a single element sensor to detect overheat conditions caused by a fire. Any excess temperature in the monitored engine and APU areas is indicated to the flight crew through cockpit visual and/or aural warnings for corrective action. The fire detection rails are comprised of two redundant continuous-loop detector elements. Each continuous loop detector is capable of indicating a fire warning if temperatures equal or exceed 100°C above the maximum operating temperature of 125°C. All components of the fire and overheat detection system are powered through the essential DC buses, enabling aircraft main battery power to energize the system for protection during APU and/or engine starting. Battery power also provides a means to test the system for integrity prior to APU and engine starts and ensures that fire and overheat detection is available during failures or malfunctions of the AC electrical power system. The engine and APU fire test switches are shown in Figure 2. Cockpit Overhead Panel: FIRE TEST and DETECTION. Access to the APU is provided by access panels in the APU enclosure and the APU fireproof access door on the side of the aircraft. Fire and overheat detection is achieved by a single pneumatic (helium) loop mounted to the enclosure roof, and fire suppression via a single extinguishing nozzle. Smoke, fire and overheat conditions may occur in many parts of the aircraft or on installed equipment. Detection of these conditions is accomplished by two basic types of detection devices: spot detectors and area detectors. The purpose of the fire detection system is to alert the crew of these conditions. These systems include the following: Engine Fire and Heat Sensing Pylon Fire and Heat Sensing Engine Fire and Heat Sensing APU Compartment Sensing Equipment Overheat Sensing and Indication Fire and Smoke Detection Indication and Test Description of Subsystems, Units and Components: Engine Fire and Heat Sensing: The engine fire and heat sensing system consists of dual-element loops in each engine and nacelle, two separate fire detection control units (one for each engine) located in the tail compartment. In addition, the system includes fire detection and fault test switches located on the Cockpit Overhead Panel (COP), two engine fire extinguishing switches and visual and audible warnings. Fire Detection Rail Assemblies: The fire detection rail assembly sensing elements are constructed of an outer stainless steel sheath which contains a temperature sensitive glass / oxide material and a coaxial cable center wire. As the temperature of the sensing element is increased, the resistance between the center wire and sheath decreases. Simultaneously, the capacitance between the center wire and sheath increases and this property provides a basis for fault / fire discrimination. Fire and overheat detection for each engine is provided in designated engine zones. Engine zone 1 is the annular space between the engine bypass duct and the cowl doors. Zone 1 is ventilated by ram air through two inlets in the upper cowl door, which exhausts through a grille in the lower cowl door. Engine zone 2 is the annular section around the high-pressure compressor, combustion section and turbine casing and is covered by the core fairings. The engine fire rail dual loops, designated loop A and loop B, each consist of six fire detection rails connected in series. Five of the rails are located within zone 1 (nacelle) and the sixth element is located within zone 2. The A and B loops are routed in parallel approximately one inch apart. Wiring connects each end of the loops to the fire detection control box. Fire Detection Link Harness: The link harness electrically connects fire detection rails as follows: A link harness connects rail 1 to rail 2 A link harness connects the right end of rail 2 to the forward end of rail 4 A link harness connects the aft end of rail 4 to the forward end of rail 3 Fire Detection Control Units (FDCUs): Left and right hand FDCUs are mounted in the tail compartment for condition monitoring (electrical resistance and capacitance) of the left and right powerplant fire detection rails. The FDCU includes two identical yet isolated detection control circuits and provides detector loop condition status to the flight deck via the Modular Avionics Unit (MAU). The FDCU is powered by the respective left and right essential bus. The FDCU also incorporates a powerplant fire / overheat detection system built-in test equipment (BITE) to provide annunciation of a loop fault condition. In the event of a fault, the flight crew can de-power the affected loop and the remaining loop will perform fire / over heat detection as a single loop system. Pylon Fire and Heat Sensing: The pylon fire and heat detection system alerts the crew of an overheat condition within the pylon. Each engine pylon area contains four thermal switches installed adjacent to the bleed air ducting. Pylon thermal switches are located forward and aft of the precooler. The pylon thermal switches are normally open thermal switches. The left and right pylon thermal switches are electrically connected to a MAU. APU Compartment Sensing: The APU compartment sensing system is made up an APU fire sensor, APU fire detection test relay, APU fire test switch and an APU fire warning light located on the COP. APU Fire Detection Loop: Fire detection for the APU is provided by a pneumatically-operated thermal sensor assembly. It consists of a stainless steel housed responder assembly with approximately six feet of stainless steel sensor tubing permanently attached. The entire assembly is welded, brazed and hermetically sealed. Enclosed within the sealed responder assembly are two pressure-sensitive switches (alarm and integrity) and an electrical connector which mates with the aircraft wiring. The detector's sensor tube (isolated from all electrical contacts) contains a special core of material and pressurized helium gas. When the ambient temperature along the tube rises, the gas pressure within increases. The increased pressure closes the alarm switch (set at a factory preset level), providing an electrical connection between the power source and the aircraft warning indications. When the temperature decreases, the gas pressure inside the detector also decreases and the alarm switch opens again. If the sensor tube is damaged in such a way as to allow the gas to escape, the integrity switch in the responder assembly will open, causing an (caution) CAS message to be displayed. The sensor tube construction is rugged enough to perform its function even if twisted, kinked or pinched. The design is highly resistant to false alarms. APU Fire Detection Test Relay: When the APU fire detection test relay energizes, a 28V DC signal is sent to the annunciator light dim / test box, which causes the APU TEST switch light in the FIRE TEST section of the COP to illuminate. A signal is also sent to the MAUs to generate an (warning) CAS message and, if the aircraft is on the ground, activate the fire alarm tone and the fire bell. APU Fire Test Switch: A system test is performed by depressing the APU TEST switch located in the FIRE TEST section of the COP. Depressing the switch illuminates the switch and energizes the APU fire detection test relay. The test function may be used during APU operation without turning off the APU. Depressing the switch also activates the (warning) and (caution) CAS message, the APU fire bell (on the ground only), and the Master Warning and Caution annunciators. APU Fire Warning Light: The APU fire warning light is located on the COP. The APU FIRE warning light illuminates any time the system is being tested or the APU thermal sensor is tripped. APU Fire Warning Speaker: An APU fire warning speaker is externally mounted in the nose landing gear wheel well in order to alert ground personnel to an APU fire during ground operations. Equipment Overheat Sensing and Indication: The equipment overheat sensing and indication system consists of normally-opened thermal switches mounted at various locations throughout the aircraft. Closure of any of the switches will route a DC signal to the CAS and will display the appropriate message to the crew. The equipment overheat and indication system can be tested by the EQPT OVHT switch. Thermal Switches: The Left Electronics Equipment Rack (LEER) contains three thermal switches on the rack. The Right Electronics Equipment Rack (REER) contains two thermal switches on the rack. These switches are installed in the equipment racks to alert the crew of high ambient temperatures, which may affect equipment operation and are set at 150°F. The LEER and REER switches provide input to the MAU. The forward baggage Electronic Equipment Rack (EER) contains two thermal switches; the aft baggage EER contains a single switch.These forward and aft switches are installed to alert the crew of high ambient temperatures which may affect equipment operation and are set at 150°F. These switches supply input to the MAUs. The aft equipment compartment (not accessible during flight) has two switches. These switches are installed in the tail compartment in the vicinity of hot air ducting to alert the crew of any leaks in the hot air manifold and are set at 250°F. These switches supply input to the MAUs. The forward floor has five thermal switches. These switches are installed below the cabin floor (between the LEER and REER) near the equipment location. Activation of these switches will alert the crew of excessive temperatures which may affect equipment operation and are set at 150°F. These switches supply input to the MAUs. The left and right floor has four thermal switches per side. These switches are installed below the aft cabin floor in the vicinity of the hot air duct and are set at 150°F. Left aft floor switches and right aft switches supply input to the MAUs. Fire and Smoke Detection: The fire and smoke detection system consists of the following: Smoke Detector: The smoke detector unit is made up of a photoelectric cell located in the baggage compartment and emits a steady beam of light across a white surface. Smoke entering the detector causes the light beam to be broken. The crew is then alerted by a red Aft Baggage Smoke message on the Crew Alerting System (CAS). On the SYSTEM TEST panel, a SMOKE DET light will illuminate. Smoke Detector Test Switch: The SMOKE DET test switch is located on the COP. When the switch is depressed, the switch ties a TEST pin to the smoke detector ground, causing the detector to activate the alarm. Emergency Smoke Evacuation Valve: A smoke evacuation valve is installed on the secondary pressure bulkhead in the aft cabin area. It vents hazardous quantities of smoke from the baggage compartment via a dedicated valve that vents to the wing-to-body fairing. Indication and Test: The fire detection indication and test system provides the crew with a means to indicate the presence of an overheat or fire condition in protected areas of the aircraft. It also provides a means to test the fire detection system. Testing of the system is possible when power is applied to left and right essential DC buses. Fire Test Switch: The FIRE TEST switches are normally operational as soon as power is applied to the left and right essential DC buses. There are three FIRE TEST switches: L ENG, APU and R ENG. These switches are located on the COP. The crew may check for normal operation of the system by performing a fire detection test. The test consists of depressing and holding the applicable FIRE TEST switch. Fire Detection Fault Switch: The FIRE DETECTION switches are located on the COP and powered by the left and right essential DC buses. There are five switches: LEFT LOOP A, LEFT LOOP B, FAULT TEST, RIGHT LOOP A and RIGHT LOOP B. The fire detection test is performed by depressing and holding the applicable switch. Fire Pull Handle: The fire pull handles are located on the cockpit center pedestal, marked L for the left engine and R for the right engine. The handles are locked in the normal down position and a 28V DC signal must be applied to a lock release solenoid in the handles for them to be pulled to the fire position. The handles incorporate a manual release button which will permit the handles to be pulled in the event of a solenoid failure. The handles incorporate lights behind a red lens cap. These lights illuminate when a fire alarm is generated by the control unit. Controls and Indications: (See Figure 2. Cockpit Overhead Panel: FIRE TEST and DETECTION through Figure 4. Engine Fuel Control Fire Detection and Warning Indications.) Circuit Breakers (CBs): The following CBs protect the fire detection and warning system: Circuit Breaker Name CB Panel Location Power Source APU CTRL 1 POP E-6 L ESS 28V DC APU CTRL 2 CPOP E-6 R BAT BUS B FIRE DET APU MCDU SSPC (#2601) L ESS 28V DC FIRE DET L LOOP A MCDU SSPC (#2602) L ESS 28V DC FIRE DET L LOOP B MCDU SSPC (#2603) R ESS 28V DC FIRE DET R LOOP A MCDU SSPC (#2604) R ESS 28V DC FIRE DET R LOOP B MCDU SSPC (#2605) L ESS 28V DC There is no dedicated circuit breaker for the APU fire detector. The detector receives essential DC power through the APU CTRL 1 or APU CTRL 2 circuit breakers on the left or right battery bus. Indications: Indication and Test: The FIRE TEST and FIRE DETECTION switches are operational as soon as power is applied to both DC essential buses. The left or right engine fire indication test is performed by pressing and holding the respective switch (L / R ENG FIRE TEST switch). The results are the FIRE TEST upper and lower segments, LOOP A and LOOP B are illuminated red, the MASTER WARN reset switch is illuminated red, the respective L / R fire handle is illuminated red, the respective FUEL CONTROL switch is illuminated red and a three chime aural warning tone sounds. The following CAS messages are associated with the engine and APU fire detection and warning system: Area Monitored CAS Message L - R Engine L-R Engine Fire (warning) L - R Engine Fire Detector Loops Engine Fire Loop Alert (warning) APU Fire Detector APU Fire (warning) L - R Engine Fire Detector Loops Fire Detection Loop Fault (caution) APU Fire Detector APU Fire Detector Fail (caution) The L-R Engine Hot (warning) CAS message is associated with an engine oil system fire or overheat or Engine Electronic Control (EEC) overheat. Summary of annunciations present in testing the engine and APU fire detection systems and annunciations for the detection of an actual fire: During a Engine Fire Detection test, all displayed messages (as well as aural indications), are identical for both left and right engines. Therefore, only messages associated with the left engine are shown below. Selection of the left FIRE TEST engine switch: FIRE TEST - L ENG upper and lower segments switches LOOP A and LOOP B illuminate FIRE TEST - R ENG upper and lower segments switches LOOP A and LOOP B illuminate Both MASTER WARNING glareshield switches illuminate (warning) and L Engine Fire (warning) CAS messages are displayed Left fire extinguishing handle illuminates red Left fuel control switch handle illuminates red The master warning switch capsules are illuminated (red W) Master warning audio sounds a repeating three chime warning Release solenoid in fire handle energizes, allowing handle to be lifted Selection of the FIRE DETECTION - FAULT TEST switch: TEST light illuminates in the FAULT TEST switch FAULT is displayed on the LEFT / RIGHT LOOP A / LOOP B switches Fire Detection Loop Fault (caution) CAS message is displayed Both MASTER CAUTION switch capsules (amber C) illuminate on glareshield Two-chime aural CAUTION tone sounds Selection of the APU FIRE TEST switch or a valid APU FIRE signal: APU FIRE TEST switch TEST annunciator illuminates APU Fire (warning) and messages are displayed (caution) CAS Limitations: APU FIRE light on the APU control panel illuminates Both MASTER WARNING glareshield switches illuminate (pilot and copilot) Three-chime aural WARNING tone sounds There are no limitations for the fire detection and warning system established at the time of this writing. Figure 2. Cockpit Overhead Panel: FIRE TEST and DETECTION DETAIL A TIL-002938A Figure 3. Cockpit Fire Detection and Warning Indications DETAIL A MASTER WARN W Illuminates red when L I R ENG FIRE TEST switch is depressed or when a valid FIRE signal is sent. VOICE WARN MASTER ORIDE INHIBIT WARN MASTER WARN VOICE WARN INHIBIT ORIDE L I R FIRE HANDLE GPWS ORIDE INHIBIT W BELOW GPWS INHIBIT ORIDE BELOW RAD G I S G I S G I S G I S RAD ALT Illuminates red when L I R ENG FIRE TEST ALT C INHIBIT INHIBIT switch is depressed or when a valid FIRE signal is sent. PILOT SIDE COPILOT SIDE DETAIL B PILOT SIDE COPILOT SIDE DETAIL C TIL-002939A Figure 4. Engine Fuel Control Fire Detection and Warning Indications SEE DETAIL A DETAIL A TIL-002940 2A-26-30: Engine and APU Fire Extinguishers General Description: The purpose of the engine / APU fire extinguishing system is to extinguish fires that may develop within the engines, the engine nacelles, or APU. Fire extinguishing subsystems include the following: Engine Fire Extinguishing APU Fire Extinguishing Description of Subsystems, Units and Components: (See Figure 5. Engine and APU Fire Extinguishing System Block Diagram.) Engine Fire Extinguishing: The fire extinguishing system consists of two identical single-shot fire extinguishing bottles containing a fire extinguishing agent and propellant, mounted in the tail compartment. The fire bottles are discharged using fire handle rotary switches located on the pedestal. Each bottle contains CF 3 Br (Halon 1301) charged with nitrogen to approximately 600 psi at 70°F. The bottles are interchangeable and each has three bonnets. However, only the left bottle has all three bonnets connected. Each extinguisher bottle will discharge its entire contents when fired. Engine Fire Extinguishing Bottles: The two fire extinguishing bottles, mounted in the upper part of the tail compartment, have three electrically-actuated explosive cartridges each. When the bottles are fired, the cartridges release the bottle contents into the bonnet which acts not only as a discharge valve but as a plumbing connection as well. The cartridges represent SHOT 1 and SHOT 2 for the engines. On the left bottle, a third cartridge is connected to the plumbing which is routed to the Auxiliary Power Unit (APU). The third cartridge is unused on the right fire bottle. Electrical power to detonate the right fire bottle (SHOT 1) cartridges is supplied by the left essential DC bus and comes through the FIRE EXT SHOT 1 circuit breaker. Electrical power to detonate the left fire bottle (SHOT 2) cartridges (excluding the APU cartridge) is supplied from the right essential DC bus through the FIRE EXT SHOT 2 circuit breaker. A temperature-compensated low-pressure switch is mounted on each bottle which sends a signal to the Modular Avionics Unit (MAU) when the bottle pressure has dropped below a set point. Engine Fire Extinguishing Shuttle Valve (Double Check Valve Tee): There are two fire extinguishing shuttle valves installed in the fire extinguishing system plumbing and are located in the tail compartment between the fire bottles. There is one valve installed in the lines to the left engine and one valve installed in the lines to the right engine. Each valve is essentially a double check valve and is T-shaped. When a fire bottle discharges its contents, the shuttle valve prevents the fire extinguishing agent from reaching the other fire bottle and ports the agent to the engine. If the second fire bottle is used, the shuttle valve moves to block off the first fire bottle and the agent is ported to the engine. Fire Extinguisher Discharge Nozzle and Tubes: The fire extinguishing discharge nozzles and tubes are located on each engine in several locations. The nozzles and tubes transfer fire extinguishing agent from the lines in the tail compartment and pylons and distribute the agent throughout the engine and nacelle area. Fire Pull Handles: The left and right fire pull handles are located on the upper left and right of the cockpit center pedestal. The fire pull handles are normally locked to prevent accidental activation of the system. When a fire is detected by the engine fire detection system, power is routed to a lock release solenoid in the fire handle allowing the handle to be pulled. Pulling the handle causes three sets of switches to change position and send a signal to the hydraulic shutoff, the electrical power system and the fuel shutoff control. This shuts off hydraulic fluid flow, electrical power and fuel flow to the engine. The fire handles incorporate a solenoid release button in the event of a solenoid failure. . When a left or right engine fire is detected by the engine fire detection system, the lock release solenoid is energized for the same side fire handle which allows the handle to be pulled. The applicable handle can then be rotated in either direction (Clockwise [CW] or Counterclockwise [CCW]) Rotation of a given handle routes a signal to the appropriate cartridge, causing the cartridge to detonate and release the fire extinguishing bottle contents as outlined below: Left Fire Handle Rotation: CCW - Discharges the right fire bottle to the left engine (SHOT 1) CW - Discharges the left fire bottle to the left engine (SHOT 2) Right Fire Handle Rotation: CW - Discharges the right fire bottle to the right engine (SHOT 1) CCW - Discharges the left fire bottle to the right engine (SHOT 2) Engine Fire Extinguishing Plumbing: On the side of each bonnet is a tubing connection. The number one bonnet tubing is routed to the bottom leg of the double check tee (shuttle valve). Pressure moves the shuttle valve up to block the top (crossover) line from the extinguishing agent and opening the center port. This allows the extinguishing agent to be discharged into the left engine fire zones. The number two bonnet tubing is routed to the top side of the left system double check tee (shuttle valve). Pressure moves the shuttle down to block the line to the left bottle, opening the center port, through the distribution lines and out to the left engine fire zones. The same actions take place if the right bottle is fired. Auxiliary Power Unit (APU) Fire Extinguishing: When the flight crew is alerted to an APU fire by the APU fire detection system, momentarily depressing the FIRE EXT DISCHD switch on the APU panel (COP) sends a 28V DC signal to an electrically-actuated explosive cartridge on the left fire bottle. This action allows the extinguishing agent to flow into the APU enclosure. Release of the bottle contents activates the temperature compensated low-pressure switch, which sends a signal to the MAU causing a (caution) CAS message. Controls and Indications: (See Figure 6. Fire Extinguishing System Controls and Indications.) Fire / Overheat Sensing: Engine Pylons: A sensed rise in ambient temperature above 250°F will cause one or more of the switches to close. When a switch closes, a (warning) CAS message is displayed and the three chime master warning tone will be audible. The CAS messages are tested by selecting the EQPT OVHT test switch on the SYSTEM TEST panel (COP). Selecting EQPT OVHT test will cause the fault messages to be displayed on the CAS. APU Compartment: The system consists of a sensor, APU fire test relay, APU fire bell logic relay, APU fire test switch, APU FIRE warning light and APU fire warning speaker. When a fire or overheat condition is detected, a signal is sent to the APU control unit which shuts down the APU. A signal is also sent to the Monitor and Warning System (MWS) and the MAU, which then allows the (warning) CAS message to be displayed. The signal is routed to the annunciator lights dim / test box, which in turn causes the APU FIRE light on the COP to illuminate. If the aircraft is on the ground, the signal is used to power the speaker amplifier and this results in an audible tone from the APU fire warning speaker in the nose wheel well. Circuit Breakers (CBs): The fire extinguishing system is designed so that a single essential DC bus can provide both fire detection and fire extinguishing for the aircraft engines. The following CBs protect the fire extinguishing system: Circuit Breaker Name CB Panel Location Power Source Provides Power To APU FIRE EXT POP E-8 L ESS DC Bus FIRE EXT SHOT 1 POP D-9 L ESS DC Bus Left Fire Handle DISCH 1 Right Fire Handle DISCH 1 FIRE EXT SHOT 2 CPOP D-9 R ESS DC Bus Left Fire Handle DISCH 2 Right Fire Handle DISCH 2 Indications: Crew Alerting System (CAS) Messages: The following CAS messages are associated with the fire extinguishing system: Area Protected CAS Message Engine Pylons L-R Pylon Hot (warning) APU Compartment APU Fire (warning) Fire Extinguisher Bottles L-R Fire Bottle Discharge (caution) Limitations: Flight Manual Limitations: There are no limitations established at the time of this writing. Figure 5. Engine and APU Fire Extinguishing System Block Diagram TIL-006893 Figure 6. Fire Extinguishing System Controls and Indications SEE DETAIL A SEE DETAIL B ---- - 3 - ---- - 2 - ---- - 1 - DETAIL B TIL-002941 2A-26-40: Aircraft Interior Overheat and Smoke Detection, Smoke Evacuation, and Portable and Fixed Fire Extinguishers General Description: Areas of the aircraft fuselage not normally accessible to the crew or passengers are monitored by sensors for conditions that indicate possible hazards or degradation of aircraft systems performance. Thermal switches detect undesirable levels of heat in areas containing electronic equipment, in the underfloor areas near hot air manifold ducting of the air conditioning system, and in the tail compartment where the APU and hydraulic reservoirs are located. The baggage compartment is monitored for both overheating in electronic equipment racks and smoke (indicating possible combustion). Smoke in the baggage compartment or anywhere in the cockpit or cabin may be evacuated from the aircraft after the cause of the smoke is eliminated. Portable and fixed fire extinguishers located in aircraft interior can be used to prevent smaller scale combustion from becoming a hazard to the aircraft. This system comprises the following subsystems, units and components: Equipment Area Overheat Detection Smoke Detection System Smoke Evacuation System (SES) Portable and Fixed Fire Extinguishers Description of Subsystems, Units and Components: Equipment Area Overheat Detection: The purpose of the Equipment Area Overheat System is to provide an indication to the flight crew that an overheat condition exists, and at what location. The system consists of normally-open thermal switches, an EQPT OVHT test switch and two Equipment Area Overheat Test relays for the system test. A total of 31 heat detector switches are installed in the aircraft interior to monitor temperature levels. The thermal switches utilize two preset temperatures: 150°F and 250°F, depending on location and type of equipment monitored. If the temperature in the monitored area reaches the trip point of the switch, the switch closes and sends a signal over wire connections to Input / Output (I/O) modules in the Modular Avionics Units (MAUs) for formatting and transmission to the Monitor and Warning System (MWS). Closure of any one of the thermal switches will result in a Crew Alerting System (CAS) message identifying the aircraft's overheat condition and location. Each of the 31 locations has several switches connected in parallel to the MAU. 28V DC is provided by the applicable WARN LTS PWR and ANN LTS circuit breakers. Closure of any one of the thermal switches will result in a CAS message identifying the aircraft location where the overheat condition exists. If a thermal switch closes in an area of the aircraft using 150°F thermal switches, it will result in a caution (amber) CAS message. Should a thermal switch close in an area of the aircraft using 250°F thermal switches, it will result in a warning (red) CAS message. Depressing the EQPT OVHT test switch, located the Cockpit Overhead Panel (COP) will cause the following Warning (red) and Caution (amber) CAS messages to display: L-R Pylon Hot (warning), L-R Aft Floor Hot (warning), and Equipment Hot (warning) L-R EER Hot (caution), Forward Floor Area Hot (caution), Baggage EER Hot (caution), and Aft Baggage EER Hot (caution) Normal Mode Operation: The Equipment Area Overheat System receives 28V DC from the LESS DC bus via the WARN LTS PWR 2 circuit breaker and from the R ESS DC bus via the WARN LTS PWR 1 circuit breaker. Whenever the buses are powered, the Equipment Area Overheat System is functional. The WARN LTS PWR 1 circuit breaker provides power to the Right Electronics Equipment Rack (REER), right pylon, right aft floor and forward floor overheat switches. The WARN LTS PWR 2 circuit breaker provides power to the Left Electronics Equipment Rack (LEER), left pylon, baggage Electronics Equipment Rack (EER), left aft floor and aft equipment overheat switches. Flight Crew Operation: Using the EQPT OVHT test switch, the flight crew should test the system before engine start. Depressing the EQPT OVHT switch provides a 28V DC discrete to MAU #1 and MAU #2, resulting in the display of the red overheat CAS messages. Other than the system test, there are no flight crew requirements. The following CAS messages are associated with the Equipment Area Overheat system: Area Monitored CAS Message Aft Equipment Area Aft Equipment Hot (warning) L-R Aft Floor Areas L-R Aft Floor Hot (warning) L-R Pylon L-R Pylon Hot (warning) Fwd Baggage Electronic Equipment Rack Fwd Baggage EER Hot (caution) Aft Baggage Electronic Equipment Rack Aft Baggage EER Hot (caution) Forward Floor Area Forward Floor Area Hot (caution) L-R Equipment Racks L-R EER Hot (caution) 18 high temperature switches set at 250°F are placed in the following locations: Two switches in the aircraft tail compartment Four switches beneath the right aft cabin floor near hot air ducting Four switches beneath the left aft cabin floor near hot air ducting Four switches in each pylon 13 lower temperature switches set at 150°F are placed to monitor electronic equipment temperature levels in the following locations: Two switches in the forward baggage EER and one switch in the aft baggage EER Five switches beneath the cabin floor near the main entrance door to monitor electronic equipment installations Three switches in the LEER Two switches in the REER Using EQPT OVHT switch, the flight crew should test the system before engine start. Depressing the EQPT OVHT switches provide a 28V DC discreet signal to MAU #1 and MAU #2, resulting in the display of all red and amber overheat CAS messages. Other that the system test, there are no other flight crew requirements. Smoke Detection System: The Baggage Compartment Smoke Detection System is provided to warn the flight crew of possible smoke or combustion within the aircraft. The system consists of the smoke detector and a SMOKE DET test switch. The smoke detector is installed in the ceiling of the baggage compartment and the SMOKE TET test switch is located on the COP. The smoke detector receives 28V DC from the Left Essential DC bus; when the bus is powered, the smoke detector is active. Clearing smoke from the baggage compartment requires opening the ball valve for the smoke evacuation system. When the smoke detector senses smoke in the compartment, it sends a signal to the CAS which produces an annunciation displayed on the primary display units. The master warning light in the fault warning panel (COP), indicates with an illuminated W. This is coupled with an auditory warning, which consists of three short beeps followed by a pause, and is then repeated. The detector is composed of a light emitting source and a photoelectric cell placed on opposite sides of an enclosure with a white interior. Vents in the enclosure allow compartment air to circulate through the interior. During normal conditions, the photoelectric cell receives a constant level of illumination from the light source and produces a steady voltage. If the air within the baggage compartment is contaminated with smoke or particles, less illumination is received by the photoelectric cell and voltage output drops, signaling the presence of smoke. The detector communicates with MAU I/O modules to initiate a MWS-generated CAS message and aural alerts. The circuitry of the smoke detector can be tested with the SMOKE DET button on the SYSTEM TEST panel on the COP, shown in Figure 7. Cockpit Overhead Panel: SYSTEM TEST Section. Actual operation of the detector is not tested with the button, i.e., no simulated smoke is passed between the light source and the photoelectric cell in the detector. Smoke Evacuation System (SES): The SES provides the means to vent smoke from the baggage compartment. It is provided in addition to the baseline Environmental Control and Cabin Pressurization Systems. In the event of a fire or smoke in the baggage compartment, the main passenger compartment is protected from penetration of hazardous fumes by the bulkhead and interior baggage door that separate the compartment. The SES system involves using the baggage compartment ambient delta-P by venting smoke from the pressurized compartment to the overboard ambient environment. To vent compartment smoke, a guarded switch on the baggage control panel, adjacent to the interior sliding door, will energize and open the Smoke Evacuation Valve (SEV). The SEV valve creates delta pressure across the flat pressure bulkhead from the baggage compartment to ambient (tail compartment overboard vent). The existing Baggage Compartment Ventilation Shutoff Valve (BCVSV) senses the delta pressure and automatically closes, thereby preventing venting the cabin to ambient. Additional airflow to the compartment is also shut off. A valve inlet in the wall of the baggage compartment interior panels ducts the air and smoke from the compartment through small lines and ducts overboard (smoke evacuation can be visually verified through a peephole in the interior door). The SEV is energized closed at the control panel. The BCVSV can then be re-energized from a reset toggle switch installed on the baggage control panel. An amber warning light and associated CAS message is displayed to the flight crew when the smoke evacuation valve is engaged. In addition the control switch to activate the SEV will be guarded to address potential inadvertent operation. These two means are included to prevent a decompression that would be caused by takeoff with the SEV in the open position. If smoke is present in the baggage compartment or anywhere in the aircraft interior, it may be evacuated to remove smoke from the interior of the aircraft. A manually operated valve, installed above the baggage compartment access door on the cabin side, (see Figure 8. Emergency Smoke Evacuation Panel) allows for smoke removal. The smoke evacuation valve handle may be rotated to the VENT / SMOKE position to remove smoke from the aircraft. Rotating the smoke evacuation valve handle allows the baggage compartment to vent outside the aircraft through the smoke evacuation line inlet in the aft part of the baggage compartment. Once smoke has been cleared from the aircraft, rotating the smoke evacuation valve handle back to the horizontal (closed) position then holding the valve reset switch up for 10 seconds allows pressure to return to normal in the baggage compartment. At the completion of smoke evacuation, normal pressurization of the baggage compartment can be restored via a Valve Reset toggle switch next to the smoke evacuation handle. It must be held to the reset position for 10 seconds to open the baggage compartment shutoff valve to restore pressurization to the baggage compartment. For additional information, see 2A-21-30: Pressurization Control System in this manual. Portable and Fixed Fire Extinguishers: The aircraft is equipped with two types of portable fire extinguishers to control fires in interior areas accessible to the flight crew. Each extinguisher is used to control fires from different sources: A Halon© or Halotron© extinguisher with a capacity of 8.2 pounds is stored on a quick release bracket in the cockpit on the pilot side. This type of extinguisher is most effective against oil or grease-fueled fires and electrical fires An extinguisher containing approximately seven pounds of a water and antifreeze mixture pressurized with nitrogen is mounted on the right side of the forward cabin bulkhead. This type of extinguisher is most effective against fires originating in paper or cloth materials Each cabin lavatory is equipped with an integrated fire detector and extinguisher unit mounted over lavatory trash bins. The unit consists of a container holding nine cubic inches of a bromotrifluoromethane extinguishing agent and discharge tubes capped with a fusible alloy. The discharge tubes are positioned over the trash container. If the temperature level below the tube caps exceeds 170-177°F, the discharge tube caps will melt and the contents of the extinguisher will be directed into the trash bin in 3-15 seconds. The unit cannot be refilled and is a disposable item. If the unit discharges it must be replaced. The detector / extinguisher is weighed periodically to ensure unit integrity. Controls and Indications: Circuit Breakers (CBs): The following CBs protect the smoke detection and evacuation system: Circuit Breaker Name CB Panel Location Power Source SMOKE DET AFT BAG MCDU SSPC (#2606) L ESS DC Bus SMOKE DET LAV MCDU SSPC (#2607) R ESS 28V DC VENT VLV AFT BAGG MCDU SSPC (#2127) L ESS DC Bus Indications: Equipment Overheat Sensing: The system consists of normally-open thermal switches mounted at various locations throughout the aircraft. The temperature setting of the switches is preselected for the installation location. Closure of any switches will route a signal to the MAUs which will then display an appropriate message on the CAS. If any of the switches for the LEER or REER trip, the following will be displayed: The CAS messages are tested by selecting the EQPT OVHT test switch, located on the SYSTEM TEST section of the cockpit overhead panel. Selecting EQPT OVHT test switch will cause the fault messages to be displayed on the CAS. Fire and Smoke Detection: When the smoke detector detects smoke in the baggage compartment, a signal is sent to the MAUs causing an Smoke (warning) CAS message to be displayed. If hazardous quantities of smoke accumulate within the baggage compartment, the emergency smoke evacuation valve, when rotated to the EVAC SMOKE position, a valve inlet in the wall of the baggage compartment interior panels ducts the air and smoke from the compartment through small lines and ducts overboard. Area Monitored CAS Message Aft Equipment Compartment Temperature �250°F Aft Equipment Hot (warning) Aft Baggage Compartment Smoke Detector Aft Baggage Smoke (warning) Aft Baggage Compartment Smoke Detector Aft Baggage Flame (warning) Aft Cabin Underfloor Area Temperature �250°F L-R Aft Floor Hot (warning) Aft Lavatory Smoke Detector Aft Lavatory Flame (warning) Aft Lavatory Smoke Detector Aft Lavatory Smoke (warning) Forward Lavatory Smoke Detector Forward Lavatory Flame (warning) Forward Lavatory Smoke Detector Forward Lavatory Smoke (warning) Galley Smoke Detector Galley Flame (warning) Galley Smoke Detector Galley Smoke (warning) Forward Baggage Compartment EER Temperature �150°F Fwd Baggage EER Hot (caution) Aft Baggage Compartment EER Temperature �150°F Aft Baggage EER Hot (caution) Forward Cabin Underfloor Area Temperature �150°F Forward Floor Area Hot (caution) Left or Right EER Temperature �150°F L-R EER Hot (caution) Left or Right PDB Temperature 90°C ±4°C L-R PDB Overheat (caution) Limitations: Flight Manual Limitations: There are no limitations established for this system as of this writing. System Notes: (1) If the baggage compartment has been depressurized, the internal baggage compartment door cannot be opened until the baggage compartment has been repressurized. Figure 7. Cockpit Overhead Panel: SYSTEM TEST Section RAT TEST FUEL TEST SYSTEM TES ICE DET TEST T SMOKE DET TEST ANN LIGHTS TEST CVR TEST PASS OXYGEN TEST ENG VIB MON TEST PRI / SEC TEST SEC EQPT OVHT TEST DETAIL A TIL-002942 Figure 8. Emergency Smoke Evacuation Panel DETAIL A EMERGENCY SMOKE EVACUATION VLV NORMAL OPS VENT / SMOKE VALVE RESET SWITCH SMOKE EVACUATION VALVE HANDLE DETAIL B TIL-007680 2A-26-50: Emergency Vision Assurance System (EVAS) General Description: The Emergency Vision Assurance System (EVAS) (see Figure 9. Emergency Vision Assurance System (EVAS)), is a smoke displacement device which provides pilot visibility when smoke is present in the flight deck. Dual EVAS units come standard on the aircraft and are attached outboard of the pilot seats on the side console structure. Both units are clearly identifiable and conveniently accessed by crew members . The EVAS system provides a clear space of air through which a pilot can view flight instruments, emergency procedures, flight plans and allows for an unobstructed view of the flight path through the front windshield. It effectively protects the flight deck from dense continuous smoke allowing pilots to safely manage a smoke emergency. EVAS operation is fully compatible with onboard crew oxygen masks and smoke goggles. The EVAS comprises the following subsystems, units and components: IVU (Inflatable Vision Unit) - a large transparent airbag specifically designed to fit Gulfstream aircraft, it inflates to form a snug fit against the forward windows, around the glaresheild and against the instrument displays. Independent power supply via a self-contained battery, pump and filter. EVAS Activation: The EVAS is easily activated using a three-step process (detailed instructions are outlined in 2. Operation below): Remove the IVU from storage box (the blower is automatically actuated upon deployment). Place the IVU on the glareshield. Pull tab on the IVU to open and assist as it inflates. Operation: Removal, Setup and Inflation: Open the Velcro tabs and remove the metal cover (the cover is tethered to the EVAS unit). Remove the white IVU, with the IVU fabric tie-down strap (wrapper), from the EVAS container. Place the IVU package on the glareshield so that the Velcro on the bottom of the IVU wrapper mates with the Velcro on the glareshield. The IVU position on the glareshield will be approximately correct if the base of the hand holding the IVU package is placed on the rear edge of the glareshield directly forward of the center of the control wheel. If vision is already impaired, pilot should feel for the location of the Velcro. The flexible air duct must be positioned outboard of the IVU and should be routed to avoid interference with any of the airplane controls. Removal of the IVU package from the container pulls a lanyard, closing the lanyard switch, automatically starting the blower and switching the internal light ON. If the blower does not start, the EVAS was installed with the master switch off, and the blower must then be started manually by pushing firmly down on the master switch, located in one corner of the open side of the container. When the blower is started, the IVU is kept compressed by the wrapper. As soon as vision assistance is needed, hold the IVU in place on the glareshield and release the IVU for inflation by sharply pulling on the tab of the wrapper. DO NOT OPEN THE WRAPPER TO INFLATE THE IVU UNLESS THE IVU IS IN PLACE ON THE GLARESHIELD. With the wrapper open and one hand holding the IVU in position on the glareshield, use your other hand to tuck the wrapper ends under the IVU. After the wrapper ends are tucked away, assist deployment of the IVU as described below: Gently rake the nearest portion of the IVU (the instrument tunnel portion) towards you. If the tunnel portion drops down between the pilot and the yoke, push the tunnel portion of the IVU to a position forward of the yoke. Using both hands, unfold and smooth out the windscreen portion. After the windscreen portion of the IVU is open and laying flat on the glareshield, hold the left lower corner of the windscreen portion of the IVU against the left lower corner of the windscreen. At the same time, hold the right lower corner of the windscreen portion of the IVU against the right lower corner of the windscreen. Hold or push these lower corners in position until the air pressure is sufficient to hold these points of the IVU in place. Smooth out any large wrinkles. If the wrapper of the IVU obstructs any of the instrumentation, fold it up onto the glareshield underneath the IVU. When the windscreen portion is near full inflation, check the instrument tunnel portion to ensure the IVU covers the flight instruments. Reposition yourself in the seat; ensure seat belt and shoulder harness are secure. IVU will fully inflate in approximately thirty (30) to sixty (60) seconds. The blower will operate continuously for several hours, and will compensate for any air that may be forced out of the IVU by control wheel movement. The blower may be switched OFF and ON as needed, to extend battery life. Deflation and Removal: When the EVAS is no longer needed, actuate the master switch in the open end of the container to switch the blower off, and deflate the IVU by manual pressure. Controls and Indications: a. Circuit Breakers (CBs): There are no associated circuit breakers with this system. Limitations: a. Flight Manual Limitations: There are no limitations established for this system. Figure 9. Emergency Vision Assurance System (EVAS) IVU PACKAGE POSITIONED ON THE GLARESHIELD DUAL EVAS UNITS INSTALLED IN FLIGHT DECK ON SIDE CONSOLES TIL-015497