(b)
Ensure the system is free of entrapped moisture or restrictions. If necessary, purge the system with dry, oil-free air or nitrogen, including those lines from the instruments. Purge the lines back through the static vent ports.
CAUTION: MAKE SURE ALL LINES (TESTER AND EQUIPMENT) ARE PROPERLY AND SECURELY CONNECTED, AND OBSERVED DURING EVACUATION OF THE SYSTEM.AN UNEXPECTED DISCONNECTIONWILL RESULT IN A SUDDEN PRESSURE CHANGE AND PROBABLY CAUSE DAMAGE TO BOTH THE TESTER AND AIRCRAFT INSTRUMENTS.
(c)
Connect test equipment lines to the pitot tubes and static vent ports. Seal static vent ports not being used with tape.
NOTE: There are two static vent ports for each pitot static system, one on each side of the aircraft. However, it is significant that the two top ports are not to the same system. The left side top and bottom ports are utilized for the copilot's instruments and the reverse for the pilot's instruments.
(d)
With the dual pilot/copilot systems installed (two pitot tubes), connect or plug tester lines such that each system can be tested individually. During test, closely observe airspeed to detect and avoid reverse movement.
(e)
Vacuumfor the test is to be pulled through the two aft static vent ports. With a vacuum pump properly connected, evacuate the static system to a pressure differential of 6.3 psig (13 inches Hg).
(f)
When the rate of climb starts to reach 2,500 fpm, slowly close off the vacuum valve. Do not exceed 2,500 fpm.
(g)
With a vacuum of 13.0 inches of mercury held in the system, the altimeter must not exceed a loss of 100 feet in 1 minute.
(h)
Uponcompletion of any tests, ensure all tape and sealing agentsare removed, especially at the static ports.
EFFECTIVITY:
040-999
34-10-00Jan
Jan10/90
PIPER AIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Flight Environmental Data (continued)
2. Inspectionand Checks of Instruments and System
Duringregular inspection of the airplane or whenever an instrument is changed or serviced, completethe following inspection and checks for the entire system:
(a)
Inspect the pitot-static system for cleanliness, security, and operation, per Advisory Circular No. AC 43-203A, for aircraft operated in controlled airspace under IFR conditions. Aircraft not operated in controlled airspace must be tested per Advisory Circular AC 43-13-1 A, Section 4 of Chapter 16.
(b)
Inspectinstrumentsfor poor condition, mounting, marking, broken,loose, or missing knobs, bentor missing pointers, and improper operation (where applicable).
(c)
Check power-off indications of instrument pointers and warning flags for proper indication.
(d)
Applypower and check for excessive mechanical noise or intermittent operation, failure to indicate,sluggishness,or indication of excessive friction. Note if the erection or warm-up time is excessive, caging functions are normal, warning flag and indicating lights and test circuits are operable.
(e)
When any air driven attitude or directional gyros are installed, inspect and change the control air filter every 50 hours. Do not adjust the vacuum regulatorwithout first installing a new centralair filter element. (Referto 36-10-00 and 37-20-00)
(f)
Note operation of instruments during engine runup. Check for intermittent or improper operation of any instrument.
(g)
Inspectcomplete system for overall condition, obvious defects, loose attachments, tubing connections,pneumatic tubing corrosion, cracks, bends, pinching, and evidence of chafing.
(h)
Check electrical connections and circuit breakers for proper size, security, and condition. Check instrument lighting system for illumination range, burned out bulbs, and defective controls. Check wiring for chafing, excessive tension, improper support, or broken lacing and ties.
(i)
Checkinstruments for overheating or contamination of equipment by foreign matter or water. Dust,dirt, and lint contribute to overheating of equipment, poor ventilation, and malfunctioning. Ensure ventilation openings in equipment housings are open and free from obstructing lint and dust.
EFFECTIVITY: 040-999
Jan10/9034-10-00
PIPER AIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. FlightEnvironmentalData (continued)
3. "q"-Differential PressureSystem
A "q" sensor circuitis a component of the pitot/static and electrical system. Thiscircuitacts as a backup in controlling certain major circuits if the landing gear squat switches become impaired.
With this system in operation ("q" pressure switch closed), the following conditions are provided:
1.
A ground is applied to the ECU ground cooling fan solenoid and cabin pressure dump solenoid.
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