ALTIMETER INDICATION CORRECT IN CADC MODE - Replace altimeter (34-13-04) and perform specified test.
ALTIMETER INDICATION INCORRECT IN BOTH CADC AND STBY MODES - Place altimeter mode switch to STBY and disconnect static line from indicator. IF -
ALTIMETER INDICATION CORRECT WITH STATIC HOSE DISCONNECTED - Restriction in static line. Check static system (34-11-00, Trouble Shooting). Recon-nect static line at completion of checks.
ALTIMETER INDICATION INCORRECT WITH IF -mode and verify correct indication. fied test. Switch altimeter to CADC altimeter (34-13-04) and perform speci-STATIC HOSE DISCONNECTED - Replace
specified test. Replace CADC (34-12-01) and perform ALTIMETER ERROR REMAINS IN CADC MODE -
PROCEDURE 2
AIRSPEED INDICATES ZERO - Substitute known good components one at a time and recheck to determine source of error. Replace defective component -
(1)
SAT indicator (34-13-03)
(2)
CADC No. 2 (34-12-01)
(3)
No. 2 TAT probe (34-12-02) Perform specified test.
AIRSPEED INDICATION NOT ZERO - Restric-tion in pitot line. Check pitot system (34-11-00, Trouble Shooting).
EFFECTIVITY ALL
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PROCEDURE 3
MODES - Check for leakage in static
system (34-11-00, Trouble Shooting).
Replace altimeter (34-13-04) and per-form specified test.
PROCEDURE 4
MACH AND INDICATED AIRSPEED ERROR REPORTED - Note if error is higher or lower than correct value. IF -
EFFECTIVITY ALL
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PROCEDURE 5
MACH ERROR REPORTED ALTITUDE AND AIRSPEED ARE CORRECT - Determine if TAS indicator is correct for captain's system and SAT is correct for first officer's system. IF -
EFFECTIVITY ALL
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CENTRAL AIR DATA COMPUTER SYSTEM - ADJUSTMENT/TEST
__________________________________________________
1. General_______
A. The operational and system tests test the air data instruments (34-13-00) with the central air data computer system. These instruments serve as installed readout devices during test. When treated as an integral system, the overall function and accuracy from input to readout is checked at one reading, and thus, interface integrity is assured. Air data instrument tests that do not require central air data computer inputs are included, since they can also be performed with the pitot-static system (34-11-00) connected to pneumatic test equipment. The operational test is self-contained and gives a confidence test of the basic air data system using onboard equipment only. The system test is predicated on a successful completion of the operational test and cannot be performed alone.
2. Operational Test - Central Air Data Computer System and Air Data Pressure_________________________________________________________________________ Instruments___________
A. General
(1)
The operational test is limited to the self-test mode of central air data computer operation. Satisfactory completion of this test assures that (1) the air data computer modules are functioning accurately, (2) the interface and failure warning system between computers and air data instruments is operating and (3) the air data instruments respond to input signals without major internal failures.
(2)
Areas not checked by the operational test are: outputs and interfaces between computers and systems other than air data instruments; accuracy and other modes of operation in air data instruments; internal computer functions of static source error correction, the function generators providing SAT and TAS outputs, altitude digital encoder operation and pressure transducer operation; two of four outputs from total air temperature probes.
B. Referenced Procedures
(1)
24-22-00, Maintenance Practices (Apply Power)
(2)
34-12-01, Removal/Installation
C. Test Central Air Data Computer System and Air Data Instruments
(1)
Turn off autopilot/flight director system and auto throttle system.
(2)
Provide electrical power (Ref 24-22-00).
CAUTION: ENSURE THAT EQUIPMENT COOLING SYSTEM IS OPERATING BEFORE
_______ TURNING ON ELECTRICAL OR ELECTRONIC SYSTEMS OR HEAT DAMAGE COULD RESULT. EQUIPMENT COOLING SYSTEM MUST BE SET FOR NORMAL COOLING AS DESCRIBED IN 21-58-00.
(3)
On panel P7, check that all circuit breakers associated with CADC 1 (four total) and CADC 2 (seven total) are closed. Also, check that circuit breakers marked ALTM VIB 1, ALTM VIB 2, XFMR 3 and XFMR 6 are closed.
(4)
AIRPLANES WITH PMS;
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