Boeing 737 Fault Interrogation for Maintenance Message

AMM TASK 31-65-00-750-801 gives instructions on how to interrogate for a maintenance message.

Fault Interrogation for a Maintenance Message

• The MAINT light on the overhead panel is used to indicate whether the airplane can be dispatched. If the light is illuminated, then there are active unconfirmed messages that need to be evaluated by airplane maintenance to either repair the fault to clear the Status message or that the MMEL allows dispatch relief and the maintenance crew selects the confirmation state on the MAINT LIGHT page.
• To view which Status message(s) are triggering the MAINT light, airplane maintenance needs to display the MAINT LIGHT page and evaluate the Status messages that are not confirmed (confirmation box is unchecked and white text).
• The MAX Display System (MDS) menu screen buttons are selectable. The green button indicates the current selection. The magenta highlight on a button indicates the cursor has captured the button and is ready to select it. The cyan buttons are not available from that screen. The cyan buttons are disabled based on airplane operating conditions. For example, some of the buttons are disabled when the airplane is in the air.
• The maintenance data pages (MAINT DATA PGS) provide these capability options: REAL, MANUAL, and AUTO for snapshot data. The REAL allows users to view the system data in real-time. The MANUAL and AUTO allow users to view up to five recorded messages.

How to Find Maintenance Messages Correlated to Active or Latched Status Messages

• Check Existing Flight Deck Effects Check as per AMM TASK 46-13-02-700-803.
• It is possible to look at correlated flight deck effects (FDE’s). These are FDEs with a corresponding maintenance message. You can also look at all FDEs that do not have a correlated maintenance message.
• Faults correlated to a status message will have an FDE type of [STATUS].
• If scheduled maintenance task (SMT) maintenance messages are found, go to AMM TASK 05-00-00-750-801 Scheduled Maintenance Task (SMT) – Repair Time Limits.

How to Extinguish the MAINT Light

• Select MAINT CTRL PGS > Select MAINT LIGHT 
• The MAINT LIGHT page does not refresh real time. If all the active Status messages are confirmed and the MAINT light is still on, then select the PREV MENU button and then reselect the MAINT LIGHT page to refresh the page. There most likely is an active Status message that was not active when the MAINT LIGHT page was initially displayed.

How to Erase Latched Status Messages

• Select MAINT CTRL PGS > Select LATCHED MESSAGE ERASE page
  • Select an applicable latched message
• Conditions causing the appearance of the Latched STATUS message must be corrected prior to erasing the message. Refer to How to Find Maintenance Messages Correlated to Active or Latched Status Messages.

How to Erase Scheduled Maintenance Task Message

• Select MAINT CTRL PGS > Select LATCHED MESSAGE ERASE page
  • Select an applicable non-active SMT message
• On the lower portion of the LATCHED MESSAGE ERASE page, there are SCHEDULED MAINTENANCE TASK (SMT) messages displayed. The SMT message is displayed when the SMT message is active. When the SMT message is active, the associated ERASE button is disabled. When the SMT message is no longer active, the ERASE button is enabled. Conditions causing the appearance of the SMT message must be corrected prior to erasing the message.
• TASK 31-65-00-860-802 Scheduled Maintenance Task (SMT) Messages Check (Separate AMM Task to Check SMT message).