2.
Groundis removed from the ice protection selectorswitch.

3.
A + removed from the gear lock solenoid.

4.
A high to low heat selection occurs for the stall recognition system lift transducer.

The"q"pressure circuit involves three double pole, double throw relays operating simultaneously. Theserelays are controlled by normal/override, "q" differential pressure, and nose gear down lock switches in series requiring all three to be closed for operation of relays. If any three switches open, the relays will deenergize.
Thenormal/override switch, located at the upper right of the landing gear handle, acts as a control to override the system as necessary andlights up when in override.
The pressure switch, mounted to the forward, left side of bulkhead 57.0, senses dynamic pressure and opens at 100 ± 4 knots with increasing airspeed and closes at 100 +4/-10 knots with decreasing airspeed. Access to the "q" switch is made through the left nose accessory panel.
4.  "q"SensorFunctionalCheck
(a) GroundCheck Procedure
This procedure may be accomplished during a pitot/static system check or as a separate
procedure.As follows:

1.  
Connectthe pitot/static tester as explained in this chapter

2.  
Slowlyincrease air speed reading on tester until voltmeter indicates 28 VDC

3.  
Check for sensor activation (Activation shall be by 100 + 4 knots maximum).

4.  
Slowlydecrease air speed reading on tester until voltmeter indicates 0 VDC

5.  
Check for sensor deactivation ( deactivation should be at 90 knots minimum).

6.  
Slowly decrease air speed reading to zero.

7.  
After all test are completed insure that all tape and/or other sealing agents are removed from the aircraft pressure or static ports.

EFFECTIVITY:

040-999
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Jan10/90

PIPER AIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL

A. FlightEnvironmentalData (continued)
4. "q"SensorFunctionalCheck(continued)
(b) Flight Check Procedure
The"q" sensor check, performed as part of the flight test procedures,is as follows:
1.  
Theaircraftmustbe at 15,000feet pressure altitude,120 KIAS.

2.  
Thefollowingconditionsmustbe met:

a.  
Landinggear andflapsdown.

b.  
ECU in LO.

c.  
TemperatureAUTO,"q"sensoroverrideswitch in NORMAL.

d.  
Left and right engine ice protectionsystemsactivated.

e.  
Leftand right pitotstallrecognitionheat switches activated.

NOTE: Observethe ammeter duringactivationto assure the function of system.
3.  Slow aircraft to 100 +4/- 10 knots at 1 knot/second. Observe"q" sensor operationin this rangeas follows:
a.  
Deice systems mustdeactivate.(Currentflowdecreaseonammeter.)

b.  
Cabin must depressurize.

c.  
ECU ground vent fan must activate.

d.  
The landing gearhandlecannotbe raised.

4.  
Accelerateto above 104 knots. Observeairspeed100 ± 4 knotswhen functions return.

5.  
Place "q" sensor override switchto OVERRIDE. Theflashing amber light must activate.

6.  
Slow aircraft to 95 knots and cycle the landing gear. It must operate normally.

7.  
Return"q"sensor override switch to NORMAL and accelerateto 110 KIAS. Cycle landing gear to operate normally.

8.  
After flight test and at every normally scheduledmaintenance event, inspect wires PR2L, PR2D,PR2B,and PR2K (going to left gear squat switch)for latent ground faults, preventinginadvertentcabinpressure loss. (Refer to 32-20-01Wiring Diagram Manual.) (Thesewires are shieldedfor mechanical protection.)

EFFECTIVITY:
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PIPER AIRCRAFT

PA-42-720(Advanced Trainer)
MAINTENANCE MANUAL
CHAPTER 35

LIST OF EFFECTIVE PAGES
CHAPTER SECTION
35-EFFECTIVITY 35-CONTENTS 35-00-00 35-00-00 35-00-00 35-10-00 35-10-00 35-10-00 35-10-00 35-10-00 35-10-00 35-10-00
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