(c)
Stop for 5 to 6 minutes to permit the system to become stable.
(d)
Write the altitude.
(e)
Stop for 1 minute and read the altitude again.
(f)
Make sure that the altitude does not go down by more than 400 feet (0.20 in. Hg).
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S 865-167
(6) Open the static cutoff valve.
S 865-272
(7) Put the captain's static system to ambient pressure.
NOTE:____ You must release the vacuum from the cutoff valves slowly.
S 865-168
CAUTION: DO NOT DISCONNECT THE PNEUMATIC TEST SET WHEN THE PITOT-STATIC
_______ SYSTEM IS NOT AT AMBIENT PRESSURE. YOU CAN CAUSE DAMAGE TO THE EQUIPMENT.
(8)
Disconnect the pneumatic test set from the test fitting.
S 845-169
(9)
Connect the captain's static system to the L-ADC.
S 845-488
WARNING: FAILURE TO REMOVE THE VINYL ADHESIVE TAPE FROM THE 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.
(10) Remove the vinyl adhesive tape from these locations:
(a)
The forward static ports (S1) on the upper left pitot-static porbe.
(b)
The aft static ports (S2) on the lower right pitot-static probe.
S 845-171
(11)
Examine the static ports for unwanted materials and rough locations on the inner and outer surfaces (Ref 34-11-01/601).
S 845-172
(12)
Remove the DO-NOT-CLOSE tags and close these circuit breakers:
(a) P6 Main Power Distribution Panel 1) 6D30 PROBE HEAT PITOT L 2) 6D33 PROBE HEAT AUX PITOT R 3) 6E01 PRIM T/E FLAP CONT AC 4) 6E02 PRIM T/E FLAP CONT DC
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747-400 MAINTENANCE MANUAL
TASK 34-11-00-795-173
8. The First Officer's Static System Leak Test (Full-Range)
________________________________________________________
A. Standard Tools and Equipment
(1)
Pneumatic Test Set
(a) Vacuum source, 10 to 30 inches of mercury (absolute)
(2)
Gages
(a) Static system test gage - required to indicate 10 to 30 inches of mercury (absolute) with accuracy of |0.1 (readable to |0.01) inch of mercury or |200 (readable to |20) feet.
(3)
Flow restrictors, control valves, cutoff valves, and pressure tape as required.
B. References
(1) 34-11-01/601, Pitot-Static Probe
C. Access
(1) Location Zone 115 Area Between Nose Gear Well and Fuselage, LH 116 Area Between Nose Gear Well and Fuselage, RH 118 Electrical and Electronics Compartment, RH
D. Procedure
S 865-273
WARNING: MAKE SURE THAT YOU DO NOT APPLY ELECTRICAL POWER TO THE FLIGHT
_______ CONTROLS. FLIGHT CONTROL SURFACES CAN MOVE AUTOMATICALLY WHEN YOU PRESSURIZE THE PITOT-STATIC SYSTEM. THIS CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO EQUIPMENT.
CAUTION: MAKE SURE THAT YOU DO NOT APPLY ELECTRICAL POWER TO THE
_______ PITOT-STATIC PROBE HEATERS. YOU CAN CAUSE DAMAGE TO THE PITOT-STATIC PROBES.
(1) Open these circuit breakers and attach DO-NOT-CLOSE tags:
(a) P6 Main Power Distribution Panel
1) 6D31 PROVE HEAT PITOT R
2) 6D32 PROBE HEAT AUX PITOT L
3) 6E01 PRIM T/E FLAP CONT AC
4) 6E02 PRIM T/E FLAP CONT DC
