Jan10/9034-00-00
PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
C Removal and Installation of Panel Mounted Instruments
1. Removal of Bezel Mounted Instruments
a.
Remove all electrical power from system.
b.
Ifthe mounting panel to which the instrument is attached must be removed:
(1.) Remove screws securing individual instrument panel.
(2.) Carefully pull the panel off.
NOTE: If the mounting panel to which the instrument is attached must be removed, ensure panel is well supported before unscrewing it from its mounting supports.
c.
Disconnect the electrical connectors or plumbing from instrument.
d.
Where two or more lines connect an instrument, identify each line to facilitate installation.
e.
Attach a dust plug or cap to each fitting.
f.
Where applicable, unscrew electrical connection from post light. Remove light by unscrewing retaining nut.
g.
Remove screws securing instrument in panel.
h.
Remove instrument from panel.
2. Installationof Bezel Mounted Instruments
a.
Placeinstrument into position on back side of panel. Securewith screws.
b.
Removethe dust plug or cap from each fitting.
c.
Attachappropriate electrical connectors or plumbing to instrument.
d.
Where applicable, insert post light and secure with retaining nut, secure electrical connection to light.
e.
Place panel into position. Securewith screws.
3. Removal of Clamp Mounted Instruments
a.
Remove all electrical power from system.
b.
Rotate clamp actuating screw counterclockwise to loosen clamp securing instrument in panel.
c.
Withdrawinstrumentfrom panel.
d.
Disconnectany attaching lines or electrical wires on rear of instrument.
e.
Cap openings as necessary.
4. Installationof Clamp Mounted Instruments
a.
Connect any attaching lines or electrical wires previously removed.
b.
Insert instrument into appropriate opening in instrument panel.
c.
Rotate clamp actuating screw clockwise; tighten clamp around instrument case.
EFFECTIVITY:
040-999
34-00-00 Jan 10/90
PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. FlightEnvironmentalData (Figures1 and2)
Thepitotsystemtransfersramairfromtheelectricallyheatedpitottubelocatedontheundersideof thefuselagenosethroughtubingtotheairspeedindicator.
Thepurposeofthestaticsystemistoventflightinstruments,pneumaticpressuregauge,cabin differentialpressuregauge,andthefuelandoil pressuregaugeto ambientatmosphericpressure.The staticsystemconsistsoffourstaticventslocatedintheaftfuselagesection,analternatestaticair sourcelocatedintheforwardfuselageandcontrolledbyaselectorvalveinthecockpit;all interconnected
bytubing.
NOTE: Asshownin Figure1,two staticportsexiston eachsideof the aircraft. The leftsidetop and rightside bottomportsareusedfor the copilot'sinstrumentsand the reverseforthe pilot's instruments.
CHART 1. FAULT ISOLATION (PITOT/STATIC SYSTEM)
Fault Cause Remedy
Tubedoes notheator clear itselfof icewith switchON. Circuitbreakerpopped. Reset.
Opencircuit. Repair.
Excessivevoltagedrop Checkvoltageat pitothead.
betweenbatteryatpitot
head.
Heatingelementburned Replacepitothead.
out.
Pointersof staticinstruments Leakin instrument,case Checkfor leakand seal.
do not indicateproperly. or in pitotlines.
Airspeedindicatorreads Leakin staticline. Checkfor leakand seal.
high.
Lowor sluggishairspeed Obstructionor leak in Removestaticlinesfrom
indication. pitotlines. all instrumentsandblow
lineclearfromcockpitto
pitot head,checkfor leaks.
Airspeedchangesas aircraft Waterinstaticline. Clearlines.
is banked.
EFFECTIVITY:
34-10-00 10/90
Jan
10/90
PIPERAIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL
A. FlightEnvironmentalData (continued)
CHART1.
FAULTISOLATION(PITOT/STATICSYSTEM) (continued)
Fault Cause Remedy
"q" backupcircuit inoperative. "q"overrideswitchfailure in overrideposition. Replaceswitch.
Defective"q"pressure Replaceswitch.
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