canatiair chaiieriQer OPERATING MANUAL PSP 606 SECTION 9 FIRE PROTECTION TABLE OF CONTENTS Subject Page GENERAL 1 FIRE DETECTION 1 Fire Sensing Cables 2 Fire and Overheat Detection Control Units Operati on Fire Warning Circuit Testing 7 APU AND POWER PLANT FIRE EXTINGUISHING 7 APU Fire Extinguishing Power Plant Fire Extinguishing 9 Squibs System Operation System Reset 13 I LIST OF ILLUSTRATIONS Figure Number Title Page 1 Firex System Components and Controls 3/4 2 Fire Warning and Fault Detection 5 3 Fire Extinguishing System Discharge Lines - Schematic 6 4 Fire Extinguishing Controls 8 5 APU Fire Detection and Extinguishing Sequence 10 6 Power Plant Fire Detection and Extinguishing Sequence 12 7 Firex Monitor Panel 14 Page 1 Mar 01
cacntiaadiiaeinr tjer OPERATING MANUAL PSP 606 SECTION 9 FIRE PROTECTION GENERAL (Figure 1) Fire protection, consisting of fire detection, warning and extinguishing, is provided by two independent systems: one for the auxiliary power unit and one for the two power plants. Each system includes fire detection and extinguishing electrical circuits, fully integrated through warning, arming and discharge switch/lights. The fire extinguishing agent (Firex) bottles, two for the power plants and one for the APU, are located in the rear fuselage equipment bay, Warning lights and switch/lights indicate low pressure in the Firex bottles and provide a means of testing the electrical continuity of the discharge cartridge circuits. Both systems are capable of detecting false fire warning signals generated by electrical shorts in the sensing cable circuits. The malfunctioning circuit is automatically isolated and a warning light in the flight compartment comes or to indicate a fire detection failure. Titanium firewalls on the engine pylon serve to isolate the power plant fire zones from the adjacent aircraft structure. The fuel, hydraulic and engine bleed air lines are all isolated from the power plant fire zones by shutoff valves located on the inboard side of the firewall. The APU is surrounded by a banadized aluminum enclosure designed to contain an APU fire. FIRE DETECTION Fire and overheat detection is provided for five detection zones, two for each power plant and one for the APU. The power plant zones are the area outside the core cowls, including the power plant accessory section and the nacelle/pylon, designated zone A, and the area inside the core cowls, designated zone B. The APU fire zone is the area within the APU enclosure. Heat sensitive fire sensing cables are routed through the fire zones and are connected to fire and overheat detection control units 1n the flight compartment. The detection control units discriminate between valid fire warnings and system faults and cause either fire warning or fault warning lights to come on in the flight compartment. SECTION 9 Page 1 Mar 01/85 cacnhaadllaeinr ger OPERATING MANUAL Fire Sensing Cables Each fire sensing cable is co-axial electrical cable consisting of two conductors, a stainless steel outer conductor grounded to the airframe and an inner conductor connected in a closed loop to a detection control unit* The two conductors are separated by a semi-conductor medium which decreases in electrical resistance as temperature increases. When the resistance of the semi-conductor decreases to a preset limit, a fire warning is sent to the flight compartment via one of the detection control units. A single break in a cable does not impair its warning capabilities but if a cable is broken in more than one place, any section between breaks will not function. Three cable segments, connected in series, are routed through the power plant fire zones A and B and a single cable segment is clamped to the inside of the APU enclosure. Fire and Overheat Detection Control Units Three fire and overheat detection control units, one for each power plant and one for the APU, are attached to the forward pressure bulkhead in the flight compartment. Each unit contains two separate alarm circuits to discriminate between valid fire and overheat warnings and false warnings generated by sensing cable short circuits. The units compare the speed and extent of sensing cable resistance change and initiate fire and overheat or fault warnings. Operation (Figure 2) Three red fire-warning switch/lights, two for the power plants, LH ENG FIRE PUSH and RH ENG FIRE PUSH, and one for the APU, APU FIRE PUSH, are located at the centre of the glareshield in the flight compartment. When a fire or overheat condition occurs in one of the fire zones, the resistance change of the fire is detected by the associated fire and overheat detection control unit and interpreted as either a valid fire warning or as a fault. If a valid fire warning is received, the detection control unit causes the appropriate fire warning light to come on, activates the fire warning bell and sends a warning signal to the master caution and warning system. In addition, if a valid APU fire warning is received and a weight-on-wheels signal is present, the APU fire and overheat detection control unit energizes the APU fire shutoff relay, initiating shutdown of the APU. The fire warning light and the fire warning bell continue to operate as long as a fire/overheat condition exists. If a fire and overheat detection control unit detects a false warning signal caused by a short in a sensing cable, it powers the appropriate amber FIRE WARN FAIL light on the fire warning test panel and automatically isolates the defective fire warning circuit. The MASTER CAUTION/RESET lights flash when a FIRE WARN FAIL light comes on. SECTION 9 Page 2 May 28/82 OPERATING MANUAL PSP 606 FIREX CONTROLS BOTTLE! ARMED PUSH TO DISCH BOTTLE 2 1 ARMH) I PUSH TO j DISCH BOTTLE ARMED PUSH TO DISCH I A ^ I HK PUSH FIRE WARNING AND FIREX DISCHARGE SWITCH/LIGHTS © LEFT FIRE WARNING TEST ©APU© RIGHT FIRE WARN FAIL I FIRE WARN 1 FAIL 1 F,RE 1 WARN 1 FAIL 1 OFF WARN TEST M m j FAULT TEST © ^ © © BOTTLE NO 1 FIREX MONITOR -1 APU t- BOTTLE NO 2 ©. LOW PRESS L SQUIB R SQUIB SQUIB LP PRESS | L SQUIB |R SQUIB LOW PRESS © PRESS TO TEST SQUIB © FIREX MONITOR PANEL FIRE WARNING TEST PANEL © Firex System Components and Controls Figure 1 SECTION 9 Page 3/4 Feb 12/88 FIREX BOTTLES AND DISCHARGE LINES 1 RIGHT POWER PLANT DISCHARGE NOZZLES 2 APU ENCLOSURE 3 APU FIREX BOTTLE 4 APU DISCHARGE NOZZLE 5 LEFT POWER PLANT DISCHARGE NOZZLES 6 LEFT DISCHARGE UNE 7 LEFTT-FITTING 8 POWER PLANT FIREX BOTTLES 9 RIGHTT-FITTING 10 RIGHT DISCHARGE LINE OPERATING MANUAL PSP 606 LH ENG, RH ENG AND APU FIRE PUSH SWITCH/LIGHTS Each switch/light is electrically connected to a fire and overheat detection control unit. Red LH ENG, RH ENG or APU FIRE PUSH lights come on if a valid fire/overheat warning is received by the associated fire and overheat detection control unit. When pressed in, switch/lights shut down power plants or APU and arm associated BOTTLE ARMED PUSH TO DISCH light(s) (refer to Figure 4). LEFT FIRE WARNING TEST © AP„ © RIGHT FIRE WARN FAIL FIRE WARN FAIL FIRE WARN FAIL WARN TEST © FIRE WARN FAIL LIGHTS Amber FIRE WARN FAIL lights come on if a false/overheat warning, generated by an electrical short in a sensing cable circuit, is received by the associated fire and overheat detection control unit. Light remains on and faulty detection circuit remains isolated from system until fault is corrected. FIRE WARNING TEST SWITCH Three-position, spring-loaded toggle switch with the following functions: WARN TEST—Simulates fire/overheat condition by grounding the sensing cables. Fire warning bell sounds and all the FIRE PUSH and the BOTTLE ARMED PUSH TO DISCH lights come on. FAULT TEST—Simulates on electrical short in the sensing cables. All three FIRE WARN FAIL lights come on. Fire Warning and Fault Detection Fi gure 2 SECTION 9 Page 5 Feb 12/88 canadair ctiailenQsr OPERATING MANUAL LEFT POWER PLANT FIRE ZONES REAR FUSELAGE EQUIPMENT BAY 1 DISCHARGE NOZZLES-ZONE B 2 DISCHARGE NOZZLE-ZONE A 3 LEFT TWO-WAY CHECK VALVE 4 POWER PLANT FIREX BOTTLE 5 BOTTLE I THERMAL RELIEF DISCHARGE LINE 6BOTTLE2THERMALRELIEF DISCHARGE LINE 7 POWER PLANT FIREX BOTTLE 2 8 RIGHT TWO-WAY CHECK VALVE 9 APU BOTTLE THERMAL RELIEF DISCHARGE LINE 10APU FIREX BOTTLE LEGEND DISCHARGE LINES - LEFT POWER PLANT DISCHARGE LINES - RIGHT POWER PLANT DISCHARGE LINE - APU DISCHARGE CARTRIDGE Fire Extinguishing System Discharge Lines Schematic Figure 3 SECTION 9 Page 6 May 28/82 cacntaiEdWaier riQGr OPERATING MANUAL D. Fire Warning Circuit Testing A spring-loaded toggle switch on the fire warning test panel with WARN TEST and FAULT TEST positions is used to check the serviceability of the fire detection warning and fault circuits. Holding the test switch at the WARN TEST position grounds all the fire sensing cables to simulate fire/overheat conditions in both power plants and in the APU. If the fire detection system is functioning correctly, the fire warning bell sounds and all the FIRE PUSH and BOTTLE ARMED PUSH TO DISCH lights come on. NOTE: The APU fire shutoff relay remains isolated from the fire warning circuits when the test switch is set to WARN TEST to permit operation of the APU during testing of the fire warning system. Holding the test switch at FAULT TEST checks the operation of the fault detection circuits in the detection control units by simulating a short in each of the sensing cable circuits. The three FIRE WARN FAIL lights come on to indicate correct operation of the fault detection circuits. When released, the test switch on the fire warning test panel returns to the centre OFF position. 3. APU AND POWER PLANT FIRE EXTINGUISHING (Figure 3) The fire extinguishing systems for the two power plants and the APU are controlled by switch/lights located at the centre of the glareshield in the flight compartment. Three Firex bottles are provided, two for the power plants and one for the APU. The two power plant bottles are interconnected by a cross-over feature which allows both bottles to be used on one power plant if necessary. The APU bottle is completely independent and discharges into the APU enclosure only. Firex bottle low pressure warning lights and test switches for the bottle discharge cartridges (squibs) are located on the Firex monitor panel on the copilot's side console. A. APU Fire Extinguishing (Figure 4) The APU Firex bottle is clamped to the rear fuselage structure above the left side of the APU enclosure and charged with Hal on 1310, a non-toxic and non-corrosive fire extinguishing agent, pressurized by dry nitrogen at 600 to 625 psig (at 15°C). The bottle is equipped with one discharge valve and is protected against thermal overpressure by a pressure relief and fill valve fitting. A pressure gauge, mounted on the bottle and equipped with an integral electric pressure switch, allows ground service personnel to monitor the charge pressure and provides the flight compartment with a bottle low pressure warning. SECTION 9 Page 7 May 28/82 canadair ctiaiientjer OPERATING MANUAL PSP 606 BOTTLE 1 ARMED PUSH TO DISCH BOTTLE 2 ARMED PUSH TO DISCH BOTTLE I AND BOTTLE 2 ARMED PUSH TO DISCH SWITCH/LIGHTS When the appropriate LH or RH ENG FIRE PUSH switch/light « pressed in after a power plant fire warning BOTTLE I and BOTTLE 2 ARMED PUSH TO DISCH lights come on rf pressure in associated Rrex bottles exceeds 225 to 275 p*< After LH ENG FIRE PUSH switch/light is pressed m. pressing ether BOTTLE ARMED PUSH TO DISCH switch/light fires the left squfc or me associated Firex bottle i.e. pressing the BOTTLE I ARMED PUSH TO DISCH swnch/kght fires left squib on Firex bottle I and pressing BOTTLE 2 ARMED PUSH TO DISCH switch/light fires left squib on Firex bottle 2. Right squibs #r* tired m a similar manner if RH ENG FIRE PUSH switch/light is pressed m response to a f*e/overheat condition in the right power plant. BOTTLE ARMED PUSH TO J DISCH J 1 ^ 1 FIRE 1 PUSH II APU BOTTLE ARMED PUSH TO DISCH SWITCH/LIGHT Following an APU fire warning, and after the APU FIRE PUSH switch/light has been pressed in, the green BOTTLE ARMED PUSH TO DISCH light comes on if pressure in APU Firex bottle exceeds 225 to 275 psi. Pressing switch/light in fires squib on APU Firex bottle. Fire Extinguishing Controls Figure 4 SECTION 9 Page 8 Feb 12/88 canadair chauenQer OPERATING MANUAL The pressure relief and fill valve fitting consists of a valve and fill fitting in series. Normally the valve prevents flow through the fill fitting but if the bottle pressure exceeds a predetermined value, a disk in the valve ruptures to relieve pressure. Discharge is made through a pipe into the rear fuselage bay. Bottle discharge is accomplished by electrically firing the squib screwed into the discharge valve assembly. Firing the squib ruptures a frangible disk in the valve neck allowing the pressurized Firex agent to flow through the bottle discharge port. Power Plant Fire Extinguishing (Figure 4) Two dual-outlet Firex bottles for the power plant fire extinguishing system are bolted to the engine mounting torque box in the rear fuselage equipment bay. The bottles are filled with Halon 1310 extinguishing agent pressurized by dry nitrogen at 600 to 625 psig (at 15°C). Each bottle is equipped with a pressure relief and fill valve fitting and a pressure gauge with integral electric pressure switch which are similar in operation to the units on the APU Firex bottle. Two discharge valves are installed on each bottle to permit interconnection of the discharge lines through two T-fittings, each containing a two-way check valve, making it possible to discharge both the bottles into one power plant if necessary. Squibs are installed in each of the discharge valve assemblies. They are identical to the squib on the APU bottle and operate in a similar manner to discharge the extinguishing agent. Squibs The squibs are Class C explosive devices screwed into the outlet port assemblies on the Firex bottles and consist of a dry explosive packed between a metal slug and an electrical connection. Ignition of the explosive packing is effected by two electric elements, each capable of firing the squib when powered by a current greater than 2 amperes. Electrical power for the squibs is provided by the 28-volt dc battery bus and the ignition circuits are designed to supply a minimum current of 4 amperes to the ignition elements. System Operation (Figures 4, 5, 6 and 7) NOTE: The operation of the left power plant fire extinguishing system is described. The operation of the APU and right power plant systems is similar except where noted. When a fire or overheat condition occurs in one of the left power plant fire zones, the appropriate fire and overheat detection control unit causes the red LH ENG FIRE PUSH switch/light to come on and the fire warning bell to sound. Pressing in the LH ENG FIRE PUSH switch/light arms the left squib on both the power plant bottles and, if the bottles are fully charged, the green BOTTLE 1 ARMED PUSH TO DISCH and BOTTLE 2 ARMED PUSH TO DISCH SECTION 9 Page 9 May 28/82 canatiair chaiientjer OPERATING MANUAL FLIGHT COMPARTMENT INDICATIONS APU LO PRESS BOTTLE ARMED PUSH TO DISCH APU FIRE PUSH RESULT EVENT L 1 OUT OUT OUT ON until APU bottle is recharged 3 2 ^ 5 o o o § 2 2 2 t o o ° o - APU FIRE PUSH light comes on. - If aircraft is on the ground, the APU fire shutoff relav is automatically energized to shut down the APU. - BOTTLE ARMED PUSH TO DISCH light comes on. - If airborne, APU fire shutoff relay is energized to shut down the APU. - APU squib is armed. - APU bleed air load control valve closes. - APU fuel shutoff valves close. - APU squib fires. - Firex agent starts discharging into APU enclosure. - Pressure switch on bottle opens as pressure drops below 225 to 276 psi and APU LO PRESS light on Firex monitor panel comes on. - APU fire goes out. Fire or overheat condition occurs in the APU fire zone. APU FIRE PUSH switch/light is pressed in. BOTTLE ARMED PUSH TO DISCH switch/light is pressed in. APU bottle fully discharges. T- CM CO rt APU Fire Detection and Extinguishing Sequence Figure 5 SECTION 9 Page 10 May 28/82 canadair chaiiencjer OPERATING MANUAL switch/lights come on. In addition, two relays, the left engine shutoff relay and the cockpit heater shutoff relay, are energized to effect shutdown of the left power plant. When energized, the left engine shutoff relay provides power to initiate the shutdown of the left engine-driven generator and close the following valves: The left firewall fuel shutoff valve The left bleed air shutoff valve The left hydraulic shutoff valve The cockpit heater shutoff relay closes the left footwarmer shutoff valve to complete the isolation of the left bleed air system and is energized only when the LH ENG FIRE PUSH switch/light is pressed. Pressing in the BOTTLE 1 ARMED PUSH TO DISCH switch/light grounds both ignition elements of the left squib on Firex bottle 1. The squib fires when the current across the elements exceeds 2 amperes, allowing pressurized Firex agent to flow through the left outlet port and associated discharge lines into both left power plant fire zones. As the Firex agent discharges, the electrical pressure switch on the bottle pressure gauge opens, the BOTTLE 1 ARMED PUSH TO DISCH light goes out and the BOTTLE NO 1 LOW PRESS light comes on. If the fire or overheat condition persists after bottle 1 has been fully discharged, the BOTTLE 2 ARMED PUSH TO DISCH switch/light can be pressed in to fire the left squib on bottle 2. The Firex agent from bottle 2 is released into both the left power plant fire zones but is prevented from entering bottle 1 by the two-way check valve located in the left T-fitting. As the pressure in bottle 2 decreases, the electrical pressure switch on the bottle 2 pressure gauge opens, the BOTTLE 2 ARMED PUSH TO DISCH light goes out and the BOTTLE NO 2 LOW PRESS light comes on. The operation of the APU fire extinguishing system is similar to the operation of the power plant system described above with the following exceptions: Only the APU Firex bottle can be discharged into the APU enclosure. No provision is made to interconnect the power plant and APU discharge lines. Pressing the APU FIRE PUSH switch/light causes the green APU BOTTLE ARMED light to come on, initiates shutdown of the APU through the APU fire shutoff relay, closes the bleed air load control valve and closes the fuel shutoff valves on the APU normal feed and negative-g protection lines. SECTION 9 Page 11 May 28/82 canadair chanenQer OPERATING MANUAL TIONS < - 2 •- 2 RTME Q- 5< CJ HX FLIG | CM OTTLE N LOW PRE m Qt75 BOTTLE N LOW PRE: Uif^HX OTTL ARME PUSH DISC CD BOTTLE 1 ARMED PUSH TO DISCH uZ uJ£-^ UX—J cu—c. Sa32. _J RESULT 2 EVE \— 3 O OUT OUT OUT 2 O omes on. u FIRE PUSH light CD 2 UJ X _J i ion occurs In nes. ££ P ond ire z eat c antf verh er pi ire or o ift pow U. w m~ h~ 3 O OUT OUT OUT 2 O lever is set to LOW 1 - LH ENG FIRE PUSH light remains on. n. Left throttle IDLE positio CS H 3 O OUT 2 O 2 O 2 O 0 DISCHA RGE I - - BOTTLE 1 ARMED PUSH I light comes on. switch/light is X CO EPU cc HENG ressed I - J Q. O 0 DISCHA RGE I i - - BOTTLE 2 ARMED PUSH 1 light comes on. •D 2 are arme "O - Left squii bs of bottles 1 an ve closes. CD - Left firewall fuel shutoff v - Left bleei d air shutoff valve c<l oses. closes. © - Left hyd raulic shutoff valv ir shuts doi u - Left eng ine- driven genera K 3 O OUT 2 O 2 O 2 O charges les. ib on bottle 1 fires. nt from bottle 1 dis power plant fire zor - Left squi - Firex age into left SHTO 1 ressed in. 3 CL RMEDP h/light is < £ ^ 5 OTTLE • ISCHs CO O * • h- 3 o ^ "5 ON until bottli is recharge 2 O OUT 2 O pens as 275 psi ESS light 3S on. switch on bottle 1 o drops below 225 to TLEN01 LOW PR monitor panel com( - Pressure pressure and BOT on Firex CO © ottle 1 fully disci harcg CD m h- 3 O 2 O 2 O OUT 2 o (mains on. w x : JO) X CO 3 0 . UJ cc u. - LH ENG I I itii on in left C © o s eat c persii verh ant | O Q. o © © £ •u!r. oO. <o I - 3 O 2 O 2 O OUT OUT charges es b on bottle 2 fires. nt from bottle 2 dis power plant fire zon - Left squi - Firex age I into left | SHTO ressed in. 3 Q. O. ju> 2 ARME witch/Ugh UJ S> CD Q K ~ g> oi\ ntil bo s recha 3 — 2 O switch on bottle 2 opens as OUT OUT OUT drops below 225 to 275 psi TLEN0 1 LOW PRESS light monitor panel comes on. - Pressure \ pressure < i and BOT on FIrex CO © ottle 2 fully discih arg CO OP 3 o - Left pow er plant fire goes Power Plant Fire Detection Extinguishing Sequence Figure * and SECTION 9 Page 12 May 28/82 OPERATING MANUAL PSP 606 System Reset After a fire warning occurs and the appropriate fire warning switch/light (LH or RH ENG FIRE PUSH or APU FIRE PUSH) is pressed, the fire warning and extinguishing system can be reset, if circumstances warrant, by pressing the fire warning switch/light a second time which returns the system to the pre-warning condition. The fire warning light goes out, the fire warning bell stops and the APU or engine previously shut down can be restarted. Attempting to reset the system with a fire or overheat condition still present in the affected fire zone(s) results in the immediate reactivation of the fire warning. SECTION 9 Page 13 Mar 01/85 canadair chai/enQer OPERATING MANUAL 'o, PRESS TO TEST SQUIB SWITCH/LIGHTS When pressed in, test electrical continuity of ignition circuits to both the ignition elements inside the associated squib. Green light comes on if ignition circuit is serviceable. Test current across ignition element is maintained at safe level by switch/light circuit. BOTTLE LOW PRESS LIGHTS Energized by circuits across electrical pressure switches integral with bottle-mounted pressure gauges. Amber LOW PRESS light comes on when associated bottle pressure drops below 275 to 225 psi and remains on until pressure increases to above 450 psi. Firex Monitor Panel Figure 7 SECTION 9 Page 14 May 28/82 |