B-737ng Cdu Fail

[New on NG]

Anybody knows this message on NG??? This message appeard after the airplane wsa parked several hours on a very hot day without APU and air conditioning. I coud not find this specifi message in VOL II and MEL. Thanks in advance.

[Golden Rivet]

I'm assuming your refering to a fail message diplayed on the FMC CDU.

A fail light on the FMC CDU indicates an FMC fail.

DDG/MMEL 34-36 refers.

[New on NG]

I´M SORRY!!! My mistake. the alert was CDS FAIL !!!!

[piton]

Are you sure it wasn't CDS FAULT ? - if it was in amber in the lower left corner of the PFD it can befound in the chapter on Flight Instruments/Displays.

"non dispatchable CDS Fault has occurred" - on the gnd only before starting 2nd engine. See page 10.11.27 in Volume 2

[IFixPlanes]

I searched in my Papers and found:

CDS - MAINTENANCE MESSAGES

CDS Messages
These are the CDS messages that can show:
— DSPLY SOURCE
— CDS MAINT
— CDS FAULT.


DSPLY SOURCE
The message DSPLY SOURCE shows when all the display units get data from one DEU. This
occurs when the display source selector is in the ALL ON 1 or the ALL ON 2 position.
After both engine are on, this message also shows when a DEU failure causes all the DUs to get
data from one DEU. On the ground with the engines off, the message CDS FAULT replaces the
DSPLY SOURCE message. The message DSPLY SOURCE does not replace CDS FAULT
when the hot battery bus power is not available because both DEUs are still operating. The
message DSPLY SOURCE does not replace CDS FAULT when the data load switch is left in
the DEU 1 or DEU 2 position. This is because the DEUs will only load software on the ground,
with at least one engine not running. If you have this fault and start both engines, the DEUs
ignore the data loader and become operational.
This message shows on the captain and the first officer PFD.


CDS MAINT
The message CDS MAINT shows when one of these circuit cards fails in either DEU:
— Graphic generator
— Discrete input/output
— Analog input/output.
This message shows on the captain and the first officer PFD.
This message shows only when the airplane is on the ground and at least one engine off.


CDS FAULT
This message shows on the captain and the first officer PFD.
The CDS FAULT message shows only when the airplane is on the ground and at least one
engine is off.

- The message CDS FAULT shows when there is a total DEU failure. A total DEU failure is
when any one of these circuit cards fails:
— Input/output controller and ARINC 429 input/output
— Power supply
— Processor.

- The message CDS FAULT shows if two or more of these circuit cards fail in a DEU or
one fails in each DEU:
— Graphic generator
— Discrete input/output
— Analog input/output.
For example, if the graphics generator fails in DEU 1 and the analog input/output fails in DEU 2,
the message CDS FAULT shows.

- The message CDS FAULT shows if the DEU initializes and it detects that these are not
compatible:
— Program pins in DEU 1 and DEU 2
— OPS and airplane type
— OPS and OPC
— OPC and OPS in DEU 1 and DEU 2.

- The message CDS FAULT shows if the DEU initializes and hot battery power is not available.
Also, the message shows when the data loader switch is in the DEU 1 or DEU 2 position. For
both of these situations, the CDS FAULT message is removed when both engines start.

- The message CDS FAULT shows if there is a miscompare of the N1, N2 or EGT data between
DEU 1 and DEU 2.
This message shows on the captain and the first officer PFD.
The CDS FAULT message shows only when the airplane is on the ground and at least one
engine is off.




HIH

Ingo

[New on NG]

I really appreciated that!!!! I thought the reason of this message was the airplane stayed under the sun in a hot day and maintenance personel thought that was because of a malfuncion GPU cart.