(3)
Remove equipment cooling if no longer required (Ref 21-58-00).

 2. System Test - Inertial Navigation System
________________________________________
 A. General
 (1)  
The following procedure accomplishes a system test of the inertial navigation system (INS) and interfacing components. The system test provides a complete system checkout of the inertial navigation system and will normally be performed only at overhaul maintenance periods or when sufficient maintenance is accomplished as to leave the integrity of the total system in doubt.

 (2)  
The test procedure allows the testing of the entire inertial navigation system including interface tests, or it allows the performance of individual tests including:

 (a)  
Battery Unit Tests

 (b)  
Data Base Validity Checks

 (c)  
Annunciator and Display Tests

 (d)  
Present Position Entry

 (e)  
Crossfill - Waypoint Entry.

 (f)  
Alignment Status Checks

 (g)  
CADC Tests

 (h)  
INS Approach Mode Tests.

 (i)  
HSI Tests

 (j)  
ADI Tests

 (k)  
Attitude Reference Test

 (3)  
The system installation, inspection and wiring continuity tests shall have been completed prior to performing these tests.

 (4)  
Correct functioning of the electrical distribution system shall be determined prior to this test.

 (5)  
Correct functioning of the equipment cooling system shall be determined prior to this test.

 (6)  
Proper completion of this test specification requires accurate knowledge of airplane test location position expressed in degrees and arc-minutes accurate to 0.1 arc-minute of latitude.

 (7)  
Proper completion of this test also requires that the following systems of components be operational during the test:

 (a)  
Central Air Data System (CADS)

 (b)  
Attitude Director Indicators (ADI)

 (c)  
Horizontal Situation Indicators (HSI)

 (8)  
The Prepare for Test procedure must be completed before the system test can be accomplished. However, the Prepare For Test procedure does not need to be repeated for each test if two or more tests are to be performed in sequence.

 (9)  
At the completion of the test(s), restore airplane to normal.

 B. Equipment and Materials
 EFFECTIVITY
 AIRPLANES WITH LTN-72RL OR  CONFIG LTN-92 INS  01 Page 507  Apr 25/93

34-41-00
 (1)  
Cards containing airplane present position and waypoint information

 (2)  
Pneumatic Test Unit (Ref 34-11-00)

 C. Referenced Procedures
 (1)  
21-58-00, Equipment Cooling - Adjustment/Test (Operating Test)

 (2)  
24-22-00, Manual Control - Maintenance Practices (Apply Power)

 (3)  
33-11-00, Pilots Panel Lights - Adjustment/Test

 (4)  
34-11-00, Pitot-Static System - Adjustment/Test

 D. Prepare for Test
 (1)  
Set mode selector switch on each mode selector unit (pilots' overhead panel P5) to OFF position.

 (2)  
Verify setting of mode selector unit remote access switch (LTN-72RL INS).

 (a)  
Remove two screws securing access cover to mode selector unit.

 (b)  
Verify that remote access switch is set to OFF.

 (c)  
Replace access cover.

 (3)  
Set both CAPT's and F/O's VOR-ILS/INS switches to INS.

 (4)  
Set ATT/COMP STAB transfer switch on the captain's main instrument panel to CAPT 1 - F/O 2 position.

 (5)  
Set INS transfer switch on the captain's main instrument panel to CAPT 1 - F/O 2 position.

 (6)  
Set VOR/ILS transfer switch on the captain's main instrument panel to CAPT 1 - F/O 2 position.

 (7)  
Provide electrical power (Ref 24-22-00).

 (8)  
Check for proper operation of pilots' panel illumination, indicator lamps and annunciator lights using master test and dim control (Ref 33-11-00).

 (9)  
Ensure inertial navigation systems No. 1, 2 and 3 have battery, control/display and mode selector units properly installed.

 (10)
 Provide cooling air to electronic equipment (Ref 21-58-00).

 CAUTION: ENSURE EQUIPMENT COOLING IS OPERATED BEFORE TURN ON OF
　
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