(b)
Place fuel shutoff control lever to full ON position. Confirm valve actuator is against stop on valve body.
(c)
Gap between control lever and stop must be 0.10 -0.20 inch. If not, proceed to step 4.
(d)
Disconnectcontrol cable at actuator arm. Loosen jam nut at clevis fitting.
(e)
Place shutoff valve actuator arm firmly against OPEN position stop pin. Place cockpit lever against stop position.
(f)
Carefullymovelever 0.10 -0.20inch off stop.
(g)
Align clevis hole with mating hole in valve actuator arm. Secure with attaching hardware.
(h)
Operatecontrol lever several times, to ensureactuatorarmon valve contacts stoppin, before control lever in cockpit contacts stop.
(i)
Reinstalllowerwing root fairing.
EFFECTIVITY:
040 999 PAGE 11
28-20-00 Jan
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Distribution(continued)
15.LeakageTest of Fuel Shutoff and CrossfeedValve
(a)Connectvalve inlet port to 50 psi air source.
(b)Close valve, apply 50 psi air pressure, and submerge valve in kerosene or similar petroleum base fluid for 2 minutes.
(c)
Ensureno evidence of leakage through valve port or around seat.
(d)
Disconnectair source. Wipe fluid from valve exterior.
16. Fuel Flow and PressureTest (refer to 28-20-00 Figure 501)
(a)At flow divider/dump valve,disconnectfuel line from flow meter and connect it to test rig inlet.
(b)
Place return line end onto nacelle or tip tank filler opening. Ensure resulting fuel pressure doesn't push it out of opening.
(c)
Connect electric power supply at APU connector. Maintain 28 volts for all tests.
(d)
Ensure all shutoff valves have full travel and wing tanks contain enough fuel to allow fuel to flow freely to main inboard tank. At least 10 gallons of fuel must exist in each main inboard tank.
(e)
For zero fuel flow check, proceed asfollows:
(1.) Turn crossfeed valve and right firewall shutoff valve off. Turn left firewall shutoff valve and
right submerged fuel pump on.
(2.) Ensure both aircraft fuel pressure gaugesread 0 psi.
(3.) Turn crossfeed valve off, and left and right firewall shutoff valves on. Close test rig
regulatingvalve and turn right submerged fuel pump on.
(4.) Ensure fuel pressure gauge reads 0 psi for left engine and maximum 35 psi for right
engine.
(5.) Compare readingson aircraft gauge with reading on test rig gauge.
(6.) Turn crossfeed valve off, and left and right firewall shutoff valves on. Close test rig
regulatorvalve and turn left submerged fuel pump on.
(7.) Ensure both fuel pressure gauges read 0 psi.
(8.) Turn crossfeed valve off, and left and right firewall shutoff valves on. Close test rig
regulatorvalve and turn left submerged fuel pump on.
(9.) Ensure left fuel pressure gauge reads maximum 35 psi and right fuel pressure reads 0 psi.
(10.) Compare readings on aircraft gauges withthose on test rig.
(f) For positive pressure fuel flow test, proceed as follows:
(1.) For left engine:
(a.) Turn crossfeed valve off, and turn left firewall shutoff valve and left submerged fuel
pumpon.
(b.) Adjust flow meter reading to 500 pph. Fuel pressure must read minimum17 psig.
(c.) Ensure aircraft fuel gauge reads minimum 17 psig.
(d.) Turn crossfeedvalveon and right firewall shutoff valve off. Turn left firewall shutoff
valve and right submergedfuel pump on.
(e.) Adjust flow meter reading to 500 pph and fuel pressure gaugereading must read
minimum 17 psig.
EFFECTIVITY:
040-999
PAGE12 Jan10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Distribution(continued)
Regulating Valve
1400Series Gauge 6" Dia. 0-60 psi 1/4of 1% Accuracy or Equiv.
HoseReturnto Tank Being Used -800
Fisherand Porter Flowmeter
= -0 Max Flow Rate 800 PPH
Accuracy+ 1% of Reading
or Equivalent Calibratedfor
Jet A-1
DisconnectLine at
Engine Pump Inlet
and Connectto Test Rig. FlowmeterShouldbe Mounted in a Vertical Position. The Elevation Shouldbe no Higherthan Injector Inlet andthe Same for All Test.
Fuel Flow Test Apparatus Figure 501
(2.) For right engine:
(a.) Turncrossfeedvalveoff,and turn right firewallshutoffvalveandright submerged fuel
pumpon. (b.) Adjustflowmeter reading to 500 pph. Fuel pressure mustreadminimum17 psig. (c.) Ensureaircraft fuel gaugereadsminimum17 psig. (d.) Turn crossfeed valveonand left firewall shutoff valveoff. Turnrightfirewall shutoff
valve and left submerged fuel pump on. (e.) Adjustflow meter readingto 500 pph and fuel pressure gaugereading must read minimum17 psig.
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