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MAINTENANCE MANUAL
PITOT / STATIC AND AIRSPEED WARNING SYSTEM — SERVICING
1. Pitot / Static System — Draining / Purging
A. Procedure
(1) Remove electrical power from aircraft.
(2) Remove all necessary interior closeouts, floorboards, covers and panels to gain access to all
pitot / static system components.
(3) Visually inspect the following for damage and system integrity:
• All pitot / static lines
• Pitot tubes
• Static ports
• Instruments
NOTE: Repair or replace all damaged or defective parts.
(4) Inspect pitot / static system water traps for water accumulation and fraying.
CAUTION: ALL EQUIPMENT MUST BE REMOVED FROM PITOT / STATIC SYSTEM
BEFORE PURGING TO AVOID DAMAGE TO EQUIPMENT.
(5) Disconnect the following components from pitot / static system:
• Cabin altitude transducer (see Cabin Altitude Transducer - Removal / Installation,
21-02-00, Removal / Installation or Code 216060)
• Cabin pressure warning switch (see Cabin Pressure Warning Switch - Removal /
Installation, 21-02-00, Removal / Installation or Code 216035)
• Digital air data computer (DADC) No. 1 and No. 2
• Overspeed warning switch (see Overspeed Warning Switch - Removal / Installation,
34-01-00, Removal / Installation or Code 345680)
• Pilot / Copilot airspeed, if required
• Pilot / Copilot altimeter, if required
• Standby airspeed indicator
• Standby altimeter indicator
CAUTION: FAILURE TO REMOVE OUTFITTER INSTALLED EQUIPMENT ATTACHED TO
PITOT / STATIC SYSTEM BEFORE PURGING MAY RESULT IN DAMAGE TO
EQUIPMENT.
(6) Using outfitter prints, determine equipment attached to pitot / static system and remove /
disconnect.
(7) Install plugs, dust caps and / or cover all ports on removed equipment and lines.
(8) Starting at farthest point from line to be purged, remove plug from line and using dry nitrogen
with an inlet pressure not to exceed 20 psig, apply pressure to pitot / static line to remove any
foreign matter accumulated in line.
NOTE: Purge for a minimum of five minutes.
Use a progressive purge method starting at furtherest point from pitot / static line to be
checked and working back toward end of line being checked.
Work one pitot / static line at a time.
(9) Install plug in pitot / static line purged in above step and continue to second furtherest point from
pitot / static port and repeat above step until all lines have been purged.
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(10) Install all equipment removed in Steps 1.A.(5) and 1.A.(6).
(11) Ensure all pitot / static lines are reconnected.
(12) Perform Pitot / Static System - Reconnect Check, 34-01-00, Inspection / Check or Code
346071.
(13) Inspect for presence of foreign objects.
(14) Install all interior closeouts, floorboards, covers and panels removed in Step 1.A.(2).
(15) Record all maintenance actions in accordance with current Federal Aviation Regulations.
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