(d)
Operate pneumatic test set and control valves to apply required pressure or vacuum to static system as indicated on test gages.
(e)
On completion of test, release pressure or vacuum on pitot system and static system.
CAUTION: TO PREVENT INSTRUMENT/EQUIPMENT DAMAGE, RELEASE OF
_______ PRESSURE OR VACUUM IS GRADUAL AND SIMULTANEOUS FOR ALL PITOT AND STATIC SYSTEMS.
(3) Restore Auxiliary Pitot-Static System No. 2 to Normal
(a) Remove all the vinyl adhesive tape and adapters from all pitot-static probes. Check that no deposits or roughness exists in or about static ports or pitot head apertures.
WARNING: FAILURE TO REMOVE VINYL ADHESIVE TAPE FROM STATIC
_______ PORTS BEFORE FLIGHT MAY CAUSE LARGE ERRORS IN AIRSPEED-SENSING AND ALTITUDE-SENSING SIGNALS, WHICH MAY LEAD TO LOSS OF SAFE FLIGHT.
CAUTION: MAKE SURE THAT YOU REMOVE ALL OF THE PIECES OF TAPE
_______ FROM EACH PITOT-STATIC PROBE. THE SYSTEM WILL NOT OPERATE CORRECTLY WHEN THE TAPE IS IN ITS POSITION.
(b)
If used, remove adapter from drain fitting or test connector in main equipment center and replace drain fitting or test connector cap.
(c)
Connect static hose to rear of differential pressure indicator at flight engineer's station panel P4 (Ref 21-33-05).
(d)
On AF 172-182; reconnect static hose to galley and toilet exhaust differential pressure switch in right crawlway, station 400 (Ref 21-26-05).
EFFECTIVITY
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(e)
Reconnect pitot lines, or disconnect test static lines, or reconnect pitot lines by means of quick-disconnect at station 2450, LBL 10, whichever is applicable, to elevator feel computer and stabilizer control module.
(f)
Perform leakage test on auxiliary pitot system No. 2 (Ref 34-11-00, Adjustment/Test).
(g)
Close T.E. FLAP LOAD RELIEF circuit breaker on P12 panel.
EFFECTIVITY
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PITOT-STATIC SYSTEM - SERVICING
_______________________________
1. General
_______
A. Servicing the pitot-static system consists of flushing and draining the system. Flushing removes or assures the absence of any foreign matter in the pitot-static system. Draining removes or assures the absence of any liquid collected in the pitot-static system sumps.
2. Equipment and Materials
_______________________
A. Flushing requires a dry air pressure source, 0 to 50 pounds per square inch (gage) with filter and gage for measuring pressure.
B. Draining requires only a receptacle and/or absorbent cloth for collecting any small amounts of liquid from each drain.
C. Pitot-static probe adapter - NAVAID, P/N PSS44600M-3-4-4.
3. References
__________
A. 21-26-05, Removal/Installation
B. 27-31-14, Removal/Installation
C. 34-11-00, Adjustment/Test (Leakage Test)
D. 52-31-21, Maintenance Practices
E. 76-12-01, Removal/Installation
4. Prepare to Flush Pitot-Static System
____________________________________
A. Verify that both static source selector valves are set at NORMAL
position.
(1)
Disconnect pitot-static system lines and cap each hose or tube. As following steps are performed, remove quick-disconnect halves installed on hoses and restrain all hoses to prevent whipping.
(a) On ALL FREIGHTERS EXCEPT LH 082; AF 151-154, nose door latch pressure differential switch (one input) located below panel P122 (Ref 52-31-21).
(2)
On flight deck, disconnect following instruments from pitot-static system:
(a)
Captain's and first officer's airspeed indicator (two inputs each), instantaneous vertical velocity indicator (one input each) and altitude indicator (one input each).
(b)
Flight engineer's differential pressure indicator (one input) (Ref 21-33-05).
(c)
On LH 011-099; AF 152-199; AZ ALL; SN 351-399; IB 415-499; plus airplanes incorporating SB 77-2060, N1 engine low idle altitude switch (S1563) behind flight engineer's panel (one input) (Ref 77-12-00).
(d)
On airplanes with CF6 series engines, engine stage cutout altitude switch behind flight engineer's panel (one input).
(3)
In left crawlway (section 41), disconnect following instruments from pitot-static system:
(a)
On LH 082-099; AF 151-190, 193-199; AZ 231 WITH SB 27-2343, AND AZ 281-299; SN 351-399; IB 415-499; MD ALL; GN 602-699; AT ALL; VM ALL, plus airplanes incorporating SB 27-2179 and SB 27-2297;
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