Discrete Input Check via Menu Mode - PRE CFM SB 73-0008 [CFML]

TASK 73-29-00-740-821-A
Discrete Input Check via Menu Mode - PRE CFM SB 73-0008

1. Reason for the Job
The Discrete Input Check function in Menu Mode verifies the current status of the hardwired discrete inputs from the aircraft. The function gives the operator the details that follow:

NAI Push Button.
Auto-Thrust Engage.
Auto-Thrust Disconnect.
TCM Enable from SEC relay.

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 31-32-00-860-012-A	Procedure to Get Access to the SYSTEM REPORT/TEST/ENG Page
EEC Discrete Input Check Main Menu Screen
EEC Discrete Input Check Special Function Screen
EEC Discrete Input Check Screen

3. Job Set-up
Subtask 73-29-00-861-088-A ** ON A/C NOT FOR ALL

A. Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 73-29-00-941-078-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) On the ENG section of the maintenance panel 50VU:

Release the FADEC GND PWR 1(2) pushbutton switch (on the pushbutton switch, the ON legend comes on).

NOTE: After the FADEC is energized, wait 10 seconds before you start the test. If you do not wait 10 seconds, the interactive mode stops the EEC self-test and this can cause unwanted faults.

(2) On the left or right Multipurpose Control and Display Unit (MCDU), get access to the SYSTEM REPORT/TEST/ENG page (Ref. AMM TASK 31-32-00-860-012).
(3) Make sure that the landing gear system is not simulated in the flight configuration.

4. Procedure
Subtask 73-29-00-740-063-A ** ON A/C NOT FOR ALL

A. Discrete Input Check Menu Mode Function
(1) The Discrete Input Check shows the current status of the hardwired discrete inputs from the aircraft. The purpose of this function is to detect if a discrete monitored by the EEC operates correctly without the start of the engine to aid in troubleshooting. The discrete inputs checked are:

NAI Pushbutton.
Auto-Thrust Engage.
Auto-Thrust Disconnect.
TCM Enable from SEC relay.

NOTE: Abort conditions do not apply to this function since the purpose of this function is only to display input signals.

NOTE: The representations that follow are made:

"F" = 1 digit engine designation (1 or 2)
"C" = 1 letter EEC channel designation (A or B)
"X" = Y (Yes, input discrete circuit is detected closed and valid) or N (No, input discrete circuit is detected open or invalid).

(2) Do the Discrete Input Check Menu Mode Function

ACTION	RESULT
1.From the Menu Mode main menu, select the key adjacent to SPECIAL FUNCTIONS (2R)	The Special Functions submenu is displayed. EEC Discrete Input Check Special Function Screen ** ON A/C NOT FOR ALL
2.From the Special Function submenu, select the key adjacent to DISCRETE INPUTS (2R)	The Discrete Input check screen is displayed. EEC Discrete Input Check Screen ** ON A/C NOT FOR ALL
3.Review the information that follows displayed on the MCDU screen to make sure that it matches the current discrete configuration selected in the cockpit	The Discrete Input check screen: NAI P/B Auto-Thrust Engage Auto-Thrust Disconnect TCM Enable from SEC relay.
4.If any of the displayed discretes are changed in the cockpit during the test, select the key adjacent to REFRESH (5R)	The EEC must be displayed again with the updated status of the discrete inputs.
5.Select the key adjacent to RETURN (6L) in order to return to the Special Functions submenu	The Special Functions submenu is displayed. EEC Discrete Input Check Special Function Screen ** ON A/C NOT FOR ALL
6.Select the key adjacent to RETURN (6L) in order to return to the Menu Mode main menu	The Menu mode screen is displayed. EEC Discrete Input Check Main Menu Screen ** ON A/C NOT FOR ALL

5. Close-up
Subtask 73-29-00-860-130-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Remove all the fixtures, tools, test, and support equipment used during this procedure.
(2) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.8 from Aug 2017] 2026.04.01 03:06:30 UTC