2 Overview Engine Fire Detection, IR Detection System Not on E90Engine Fire Extinguishing – Halon based fire extinguishingNot on U21 or E90Portable Extinguisher – at least one halon in the cockpitOverheat protection for Bleed airEmergency Portable Breathing DevicesInfrared means “below red” in the electromagnetic spectrum (energy)Photocells (sensors) turn IR energy into electron flowController/Amplifier senses current flow- if threshold exceeded, it creates annunciations3 photocells per engine
4 Sensors / Detectors Infrared photocells Photocells induce electron flow when exposed to infrared radiationInfrared means “below red” in the electromagnetic spectrum (energy)Controller/Amplifier senses electron flow- when threshold is exceeded, it creates annunciations
5 Sensors / Detectors 3 Sensors in each engine compartment Each sensor looking at a different zone in the engine compartment1-forward of intake2-upper accessory case3-lower accessory case3 photocells per engineNot a smoke detectorZone 1Zone 2Zone 3
6 Amplifier-Controller Amplifier-Controller translates sensor detection to cockpit annunciationsAmplifier-Controller allows for testing the systemIllustration shows the relationship between sensor/detector and amplifier-controllerController/Amplifier senses current flow- when threshold is exceeded, it creates annunciationsNo fire detectedL Engine Fire Detected
7 Annunciators U21A “LH/RH FIRE WARNING” and “FAULT WARN” U21H “FIRE L/R ENG” and “MASTER WARNING”U21AU21H
8 Annunciators C12 T-handle – “#1/2 FIRE PULL” and “MASTER WARNING” 200 “FIRE L/R ENG” and “L/R ENG FIRE-PUSH TO EXT” and “MASTER WARNING”C12200
9 Test Switch U21 – 8 position switch “Test Switch Fire Detection” C12 – 6 position switch “Fire Protection Test”200 – 7 position switch “Test Switch Fire Det & Fire Ext”Only turn counter clockwise unless the test failsU21C12200
10 ElectricalCircuit Breaker in Cockpit – with CB pulled, detection won’t workDual-fed bus – power must be on the aircraft in order to detectU21200C12
12 Test The three DET/DETR positions of the test switch Position 1 Position 1 tests the fwd intake sensor of both enginesPosition 2 tests upper accessary case sensor of both enginesPosition 3 tests lower accessory case sensor of both enginesPosition 1Position 2Position 3
13 TestSensors are tested by increasing the output voltage of each sensorSensors are tested by increasing the output voltage of the sensor to a sufficient level to signal the amplifier as if a fire is present.Clear the master between each test position to check master warning is triggered.Test should be done at a deliberate pace. Running quickly through each test position isn’t a valid test.
14 TestU21A and U21HBoth “LH/RH FIRE WARNING” / “FIRE L/R ENG” annunciators illuminate“FAULT WARN” / “MASTER WARNING” is triggeredAudible warning hornU21AU21H
15 Test C12 C12 Both T-handle “#1/2 FIRE PULL” annunciators illuminate “MASTER WARNING” is triggeredC12
16 Test 200 200 Both “FIRE L/R ENG” annunciators illuminate “MASTER WARNING” is triggered“L/R ENG FIRE PUSH TO EXT” light on both sides200
17 Fire IndicationAn actual fire has the same indications but will only be on the side of the fireU21AU21HC12200
18 Referenced Procedures Engine Fire/Failure/Severe DamageEvacuation/Engine Fire on the GroundU21C12
19 Engine Fire Detection: Abnormalities False Fire IndicationSun light/ reflectionsWater/ moisture in sensor/wiringBad sensor
25 Fire Extinguishing Bottle One bottle per engineDischarges through plumbing to nozzles into fire zonesOne pressurized halon 1301 bottle for each engine, located in wheel wellsDischarges through plumbing to nozzles into all fire zones for that engine not the intake
26 Fire Extinguishing Bottle Pressure provides the motive flow for the halonFully discharges in .08 secondsBottle will fully discharges in .08 secondsDischarges into fire zones, not intakeZone 2&3 nozzlesZone 1 nozzles
27 Pressure Gauges Pressure indicates quantity of halon available Gauge visible from the wheel wellAmbient temperature determines the pressure limitsAftPressure indicates quantity of halon available-low pressure indicates loss of halon - servicing requiredGauge visible from the wheel well-Orientation is different between the L and R wheel wellMinimum pressure chart should be referenced-pressure will be different for the same quantity of halon at different temperaturesLooking up, LH Main
28 Squibs Pyrotechnic squib cartridge holds plug in place “firing” the squib releases the plugHalon flows to the discharge nozzlesBottle will fully discharge in .08 seconds
29 Annunciations C12 Red “PUSH TO EXTINGUISH” indicates squib is armed Indicates squib has discharged
30 Indicates a fire is detected Annunciations200Indicates a fire is detectedIndicates squib has discharged
31 Only fires the bottle that has been armed by the T-Handle ActuationC12Pull appropriate T-HandleLift clear coverPush the annunciator to discharge the bottleOnly fires the bottle that has been armed by the T-Handle
32 Actuation 200 Lift clear cover Push the appropriate annunciator to discharge the bottleBoth buttons are always armedOne switch per side
33 Test SwitchTwo remaining positions of the rotary test switchC12200
34 ElectricalHot battery bus – bottles can be discharged with the batt master off
41 Bleed Air Supply Line Hot bleed air from engine is delivered to cabin P3 air leaves the engine at 640⁰FA broken line threatens smoke and fireExamples of materials that can cause smoke or fire with a bleed air leakMIL-H-5606 flash point around 200°FZipties give way at 185⁰F5606 flashpoint: 200⁰FKydex burns at 400⁰FThough bleed air is very hot, at normal restricted flow rates it will become somewhat stagnant in the lines, allowing it to cool significantly in the lines. If there is a leak, the faster flow allows less time to cool in the lines. This will lead to hotter realized bleed air temps spilling out of the damaged line.
42 Heat Sense LinePressurized, plastic line runs along side bleed air lines18psi originates at pneumatic controllerAt 204⁰F the plastic line meltsTypically blue plastic line running alongside bleed linesUses same bleed air it is monitoring to pressurize the line-Pressure is significantly reduced to 18 psi by the pneumatic regulatorBleed air used for monitoring pressure is significantly cooler due to-Length of run from engine source to pneumatic regulator-Significant reduction of pressure (114 psi to 18 psi)-Lack of actual flow in pressurized line (Bleed air does not flow through the sense line, it only pressurizes it (like a garden hose that is turned on at the house but the nozzle is closed)Melting temp of the plastic sense line is 204°F
43 Pressure switch located under Pressure Switch (C12/200)One for the LH and RH sense linesBelow 18psi, this switch closes to warn the pilotLocated at the end of the sense line opposite to the pressure sourceOne switch per sideCloses electrical contacts at or below 18psi, open above 18psiPressure switch located underco-pilot seat
44 Pressure Switch (U21)There are two pressure switches one for each side located just before the check valves.Located on a standoff pipe at the end of the bleed air line near the mixing valve. Senses pressure within the bleed air supply line
45 Annunciator Light (C12/200) “L/R BL AIR FAIL” and “MASTER WARNING”The pressure switches illuminate these annunciators respectivelyC12200
46 Annunciator Light (U21) “LH/ RH BLD AIR FAIL” and “MASTER WARNING” U21 AU21 H
48 Bleed Air Line Rupture C12/200 The hot air melts the sense line (and anything else around it)The low volume pressure in the sense line escapesPressure switch closes at18psi“L/R BL AIR FAIL” annunciator Illumes with “MASTER WARNING”A loss of pressure in the sense line indicates a serious threatWhen bleed air is ported to the supply line, the heat sensing line is pressurized with a very small volume of bleed air (not enough to heat it up)The heat sensing line is a closed line with no flow. Bleed air pressurizes the line only.If a bleed air supply line begins to leak, the hot air will melt the plastic sensing line, sense line pressure drops triggering the pressure switchLoss of pressure lights the “L and R BL AIR FAIL” annunciatorC12200
49 Bleed Air Line Rupture U21 If a break in the bleed air line should occur the air pressure in the line would drop causing the pressure switch to open and the “LH or RH BLD AIR FAIL” to illume.
52 Between FO rudder peddles Temperature SwitchSenses air temperatureLocated in mixing plenum of the U21Located in the duct after of mixing plenum of the C12/200Located aft of where the hot and cold are mixed togetherU21Between FO rudder peddlesC12/200RH Mid cabin
55 Air Temp in Duct RisesAir in the ducting becomes too hot (potential for smoke)Temperature switch closes circuit (225°F -300°F)“DUCT OVERTEMP” annunciator illumesU21AC12Air temp in duct reaches 225°F -300°FLight illuminatesPilot must correct by increasing cold air volume or reducing hot air volume (will be discussed in bleed air system)U21H200
60 PBE Part 25Part 25 requiredFixed (stationary, or built in) protective breathing equipment must be installed for the use of the flightcrew, and at least one portable protective breathing equipment shall be located at or near the flight deck for use by a flight crewmember. In addition, portable protective breathing equipment must be installed for the use of appropriate crewmembers for fighting fires in compartments accessible in flight other than the flight deck.
61 EPOS Components EPOS - Model MR-10096AF Hood -The hood is a multi-layer design of polyimide film and PFA film, which provides excellent resistance to most chemicals. It measures 13 inches at its circular base, and is 19 inches high, with an internal volume of approximately 23 liters (slightly less than 1 cubic foot).-The EPOS hood’s ability to withstand fire is limited-EPOS hood can withstand a 1000°C (1,832°F) flame for five seconds without burning through.-The EPOS hood can withstand radiant heat of 1.0 BTU/sq. ft. for up to 60 seconds.Neck Seal-The neck seal is a high strength, highly elastic silicone rubber design that fits all adult sizes with an 11 to 19 inch neck without adjustment.Oxygen System-One cylinder of compressed Aviator’s Grade Oxygen at 3,000 psi, with an equivalent ambient volume of approximately 18 liters, is mounted on the bottom side of the neck seal.Carbon Dioxide Scrubber-Carbon dioxide is a natural byproduct of respiration. Because the EPOS is a closed circuit system, it is necessary to remove the carbon dioxide that builds up inside the hood. This is accomplished with a passive chemical scrubber. The average carbon dioxide concentration will be kept below 4% for the duration of use, but may reach a momentary peak of 7%.Humidity Indicator-Humidity indicator to indicate integrity of EPOS packaging for preflight purposes, if the humidity indicator is blue the unit is serviceable. If the humidity indicator is pink, the unit is to be replaced.
62 EPOS Operation 1. OPEN CLOSURE FLAP OF STOWAGE POUCH. 2. GRASP STOWAGE POUCH W/ ONE HAND AND WITH OTHER HAND PULL RED TAPE STRIP OF BARRIER POUCH.3. REMOVE THE EPOS UNIT FROM BOTH POUCHES.In the process of donning the unit, the user must grab the oxygen cylinder in one hand and the red ball in the other in order to pull the hood open. The red ball is tethered to the oxygen seal on the bottle. Pulling the hood open pulls the red ball apart from the bottle which pulls the oxygen seal off of the bottle starting the flow of oxygen. The force required to pull the seal off is approximately 12 pounds.4. PULL THE RED BALL WITH ONE HAND WHILE HOLDING THE OXYGEN CYLINDER WITH THE OTHER HAND.
63 7. REMOVE HOOD AFTER YOU ARE CLEAR OF HAZARD EPOS Operation5. SPREAD NECK SEAL OPEN WITH HANDS. PALMS ARE TO BE FACING EACH OTHER.6. PULL THE EPOS OVER THE HEAD.Even though the flow of oxygen stops after five minutes, there is sufficient oxygen inside the hood for the escape situations shown in the “Duration of Use”-Duration of Use: All emergency rescue and escape situations are different, and it is not possible to provide an exact duration time for all situations. Also, the size of the EPOS user will affect usable life, with heavier individuals consuming oxygen more rapidly. However, for an average male, the following typical escape situations are useful in predicting how long the EPOS will last-Sitting, waiting to be rescued -Up to 60 minutes-Waiting 17 minutes to be rescued, then rapid evacuation -Up to 21 minutes-Moderate walking (3 mph) -Up to 18 minutes-Rapidly walking, on a flat, out of a building -Up to 8 minutes-Rapidly walking up 15 flights of stairs -Up to 3 minutesWhen the unit deflates to the point where it touches the wearer’s head and face, the unit’s useful life has ended and must be removed7. REMOVE HOOD AFTER YOU ARE CLEAR OF HAZARD