• IRU Codes

  
  IRU ISDU fault code Notes:

  1.IRS status codes show on the IRS DISPLAY of the ISDU. Some codes give the condition of the IRS system. Some codes give instructions.
  
  2.Two or more codes at the same time cause the ISDU CLR key light to come on. Push the CLR key to show the codes in sequence.
  
  3.The IRS status codes come from the IRUs. Put the system display (SYS DSPL) selector in the L position to see codes from IRU 1. The R position shows codes from IRU 2.
  
  4.The residual groundspeed error is 21 knots or larger, replaced IRU.

  
  
  Recommended Action:

  -These are the ISDU fault codes and recommeded actions:
  
  01-REPLACE ISDU.
  
  02-VERIFY AND THEN RE-ENTER A KNOWN ACCURATE PRESENT POSITION (TWICE, IF REQUIRED, USING IDENTICAL ENTRIES). IF FAULT LIGHT PERSISTS, PLACE MODE SELECTOR TO OFF. WAIT UNTIL ALIGN LIGHT GOES OUT (APPROXIMATELY 30 SECONDS). RESTART THE 10-MINUTE ALIGNMENT PROCEDURE. IF MALFUNCTION CODE 02 PERSISTS, REPLACE IRU.
  
  03-PLACE MODE SELECTOR SWITCH ON IRS MSU TO OFF. WAIT UNTIL ALIGN LIGHT GOES OUT (APPROXIMATELY 30 SECONDS). RESTART THE 10-MINUTE ALIGNMENT PROCEDURE.
  
  04-RE-ENTER THE IDENTICAL POSITION TO THE LAST POSITION ENTERED, USING THE IRS ISDU OR THE FMC CDU. TO RE-ENTER PRESENT POSITION USING THE FMC CDU, THE PRESENT POSITION MUST BE RELOADED INTO THE CDU SCRATCH PAD REGARDLESS OF WHETHER A PREVIOUS POSITION OR BOX PROMPTS ARE DISPLAYED ON THE SET IRS POSITION LINE. THEN LINE SELECT KEY (LSK) 4R TO TRANSMIT THE PRESENT POSITION TO THE IRS. IF ALIGN LIGHT CONTINUES TO FLASH, PLACE MODE SELECTOR SWITCH TO OFF. WAIT UNTIL ALIGN LIGHT GOES OUT (APPROXIMATELY 30 SEC). RESTART THE 10-MINUTE ALIGNMENT PROCEDURE.
  
  05-REPLACE LEFT DAA. IF MALFUNCTION CODE 05 PERSISTS, CHECK EQUIPMENT THAT INTERFACES WITH LEFT DAA.
  
  06-REPLACE RIGHT DAA. IF MALFUNCTION CODE 06 PERSISTS, CHECK EQUIPMENT THAT INTERFACES WITH RIGHT DAA.
  
  07-REPLACE DADC.
  
  08-ENTER PRESENT POSITION. IF MALFUNCTION CODE 08 PERSISTS, USE ISDU TO ENTER PRESENT POSITION.
  
  09-ENTER MAGNETIC HEADING, USING THE ISDU OR FMS CDU POS INIT PAGE 1/2. IF THE ISDU IS USED TO ENTER HEADING, THE LETTER H MUST BE ENTERED FIRST. HEADING FLAGS WILL DISAPPEAR WHEN HEADING IS ENTERED.
  
  10-ENSURE THAT BOTH IRU'S ARE ON AND ARE RECEIVING POWER.

  
  Applicable deferrals 34-35-02=IRS data display (AFT Overhead Panel).
  34-35-03=IRS Ground Crew call horn may be inoperative.
  34-49=Right IRS DC Power Supply System

Training Only