(c) Disconnectthreewiresconnectingsquib unit with aircraftharness.
WARNING: CHARGEDBOTTLESMUST BE HANDLED WITHCARETO AVOID DAMAGING THE SEAL. DO NOT BRINGELECTRICALCURRENT IN CONTACTWITH TERMINALSON SQUIB ASSEMBLYOF A LOADED UNITOR ACCIDENTAL DETONATIONCOULD RESULT.
(d) Disconnectdischargepipeat fire seal fitting and remove nut and washer fromfittingon forward side of fire seal.
(e)Supportbottle;loosenmountingclampand remove bottle.Removefitting from dischargeport of squib housing.
UpperCowling Skin
Fire Extinguisher
/
I
II
Pressure Gauge
Clamp
EngineFireExtinguisher
Figure 401
EFFECTIVITY:
040-999
Jan 10/9026-20-00
PIPERAIRCRAFT
PA-42-720(Advanced Tralner)
MAINTENANCEMANUAL
A. Extinguishing (continued)
3. Installationof Fire Extinguisher
(a)
Installconnectorfitting into squib housingandtighten.
(b)
Positionbottleinto proper positionwithdischargetube connector fittingprotrudingthroughhole in fire seal.
(c)
Securebottle by tightening clampandinstallingnut and washeron fitting protrudingthroughfire seal.
(d)
Connectand secure dischargepipe to fire seal fitting.
(e)
Checkplacementof discharge nozzles(shownin Figure 401). Nozzles must be positionedas shownto obtain proper dispersalof extinguishing
agent.
(f)
Ensureall aircraftelectricalpoweris off; connect wires to proper terminalson squibassembly.
(g)
Install engine cowling.
(h)
Turnaircraft electrical systemon, press annunciatortest switch, and verify leftand right engine fire extinguisher inoperativeindicatorlights are operating.
4. ServicingFire Extinguisher Bottle
(a)
Checkfor leakage ordamageto container.
(b)
If bottle is not being replaced,weighit to be sure it is within 0.25poundsof total weight stampedon data plate.
(c)
If bottle is underweight or damaged, replacewithserviceableunit.
(d)
Ensureindicatedpressurereadingonfire extinguisher bottleis within specification givenin Chart1.
5. Replacing Fire Extinguisher Squib Assembly
WARNING: DISPOSE OF REMOVEDSQUIBASSEMBLYIN A SAFE MANNER AS WITH ANY OTHER EXPLOSIVE DEVISE.
Thesquibassemblyhasa total life of 10 years(Five years shelflife and five years time-in -
service).Thesquibassemblymust be replaced afterfive years time-in -service.To determine
servicelife, check the date the squib assemblywasinstalledin the aircraft, not the date which the
squibassemblybeganits shelf life. Do not installany squib assemblythat has exceededits five
year life onto any aircraft.
EFFECTIVITY:
040-999
PAGE3
26-20-00 Jan10/90
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. Extinguishing(continued)
6. Testing Extinguishing System
by turning aircraft master switch on, pressing annunciator display test switch, and verifying that left and right engine fire extinguisherinoperativeindicator lights are operating. A more thorough check is as follows: (1.) Assure all aircraft electrical power is off and all circuit breakers are disengaged. (2.) Disconnect electricalwiring harness from fire extinguisher squib in one engine
compartmentand connect a test lamp across disconnectedwires of harness. (3.) Reset circuit breakersand turn master switch on. (4.) Engage appropriateengine fire extinguisher switch in cockpit and verify that test lamp
illuminates. (5.) Reset fire extinguisher switch,turn master switch off, disengage circuit breakers, and disconnecttest lamp.
(a) A quick check of the system electrical circuit is accomplished
WARNING: DO NOT USE A VOLT-OHMMETER, BATTERYPOWERED CONTINUITY LIGHT, OR SIMILAR DEVICE WHEN TESTING SQUIB ASSEMBLY. USE OF TEST DEVICES WHICHPASS MORE THAN 30 mA CAN DETONATE SQUIB.
(6.) Connect squib tester (Model 115 squib test, American Standard, Monrovia, California) to squibterminals and check for nominal resistance of 1.15 ± 0.25 ohms. Disconnect squib tester.
(7.) Ensure aircraft electrical system is deactivated; reconnect system wiring to squib
assembly terminals, assuring ground wire is connected to ground terminal. (8.) Repeat steps a through g for opposite engine. (9.) Pressure check fire extinguisher containers periodically to ensure pressure is between
minimum and maximum limits prescribed by manufacturer. (Refer to pressure temperature correction table on container (bottle) or refer to Chart 1.)
NOTE: Pressure changes with ambient pressure must fall within prescribed limits. If pressuresdo not fall within prescribedlimits,replace extinguisher container.
CHART 1 PRESSURE-TEMPERATURECORRECTION
Temperature -60 -40 -20 0 +20 +40 +60 +80 +100 +120
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