F. Point probe in the airplane's forward direction and connect hose fittings at base of probe.
CAUTION: APPLY COUNTERPRESSURE USING WRENCHES ON EACH SIDE OF FITTING
_______
DURING ASSEMBLY, TO PREVENT TUBING OR FITTING DAMAGE.
NOTE: The hose fittings are in three different sizes so they cannot be
____
interchanged.
G. Align upper pitot-static hoses (Fig. 401).
CAUTION: HOSES MUST BE ALIGNED (FIG. 401), OR WATER COULD COLLECT IN
_______ HOSES AND CAUSE INACCURATE INSTRUMENT READINGS OR DAMAGE.
H. Connect electrical connector to probe.
I. Grasping probe strut, carefully push probe straight in toward airplane such that base seats into cutout in airplane skin.
CAUTION: DO NOT BEND OR TWIST PROBE TO ALIGN PINS DURING THIS PROCEDURE
_______
OR IT MAY BE DAMAGED.
J. Verify that probe base is seated flush with airplane skin.
K. Install six screws in probe base mounting holes and tighten.
L. Do a low-range leak test of the pitot-static system (Ref 34-11-01, Adjustment/Test).
M. Lightly coat nylon cord with sealant. Install cord with one full wrap at bottom of cavity and one full wrap at outer surface of cavity.
NOTE: If gap is too small to install cord around entire periphery,
____
install cord where possible.
N. Fill cavity between probe base and airplane skin flush with skin, using BMS 5-95, class B 1/2 sealant (Ref 20-30-05).
O. Cure probe base sealant until sealant cannot be indented. Cure time of sealant may be accelerated with application of heat (Ref 51-31-01).
EFFECTIVITY
ALL 01 Page 404 Apr 25/9734-11-01
PITOT-STATIC PROBE - ADJUSTMENT/TEST
____________________________________
1. Pitot-Static Probe Test
_______________________
A. General
(1) A leakage check must be performed on affected subsystems after each pitot-static probe installation. Flushing is not normally required and must be performed only if there is reason to believe foreign material was introduced into pitot-static system hoses during disassembly/assembly.
B. Equipment and Materials
(1)
Pneumatic Test Unit
(a)
Dry air pressure source (1 required), 30 to 35 inches of mercury (absolute)
(b)
Vacuum sources (2 required), 10 to 30 inches of mercury (absolute)
(2)
Adapters
(a) Pitot-static probe adapter - 884EE with RCF kit P/N 508 or; RCF Seals & Couplings, Inc., P/N 508747.
(3)
Gages
(a) Pitot system test gage - required to indicate:
1) Pressure of 30 to 35 inches of mercury (absolute) with accuracy of | 0.16 (readable to | 0.03) inches of mercury or 300 (| 5) (readable to | 1) knots
2) Vacuum of 10 to 30 inches of mercury (absolute) with accuracy of | 1 inch of mercury minimum
(b) Static system test gage - required to indicate vacuum of 10 to 30 inches of mercury (absolute) with accuracy of | 0.1 (readable to | 0.01) inches of mercury or | 200 (readable to | 20) feet.
C. Referenced Procedures
(1)
24-22-00, Maintenance Practices (Apply Power)
(2)
31-31-01, Servicing
(3)
30-31-00, Adjustment/Test
(4)
34-11-00, Maintenance Practices (Pressurization)
D. Prepare to test pitot-static probe.
(1)
Check that pitot-static probe heaters remain off during test.
(2)
Verify that captain's and first officer's static source selector valves are in NORMAL position.
(3)
Connect pitot (pressure) source in pneumatic test unit through pitot control valve to pitot cutoff valve.
(4)
Connect static (vacuum) source in pneumatic test unit through static control valve to static cutoff valve.
(5)
Open TE FLAP LOAD RELIEF circuit breaker on P12 panel.
WARNING: FAILURE TO OPEN T.E. FLAP LOAD RELIEF CIRCUIT
_______ BREAKER MAY RESULT IN INJURY TO PERSONNEL.
(6) If captain's pitot-static probe (upper left) is to be checked for leakage:
(a) Temporarily seal static ports on No. 2 auxiliary pitot-static probe (lower right).
EFFECTIVITY
ALL 04 Page 501 Aug 25/9234-11-01
WARNING: WHEN THE STATIC PORTS ARE COVERED, MAKE SURE THAT
_______ CONDITION IS VISIBLE FROM THE GROUND. FAILURE TO OBSERVE AND REMOVE COVERINGS OVER STATIC PORTS BEFORE FLIGHT MAY CAUSE LARGE ERRORS IN AIRSPEED SENSING AND ALTITUDE SENSING SIGNALS, WHICH AMY LEAD TO LOSS OF SAFE FLIGHT.
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