B737 DEU EEC

[TyRod]

Hi guys,

Need some inputs on this:

"Loss of either DEU results in a loss of signal to both EECs. The EEC ALTN lights illuminate and each EEC reverts to the alternate mode to prevent the engines from operating on a single source of data."

I was convinced that the DEUs was receiving signals from the EECs and then were responsible for displaying the datas on the DUs.

What am I missing here?

Also, can somebody tell me why a hard alternate mode have been installed.
Was keeping the EEC in soft not good enough? (even with the possible exceedances)

In alternate mode, is the Thrust levers controlling directly the HMU?

Thanks

Thanks

[Jet II]

The DEU's send and receive data to and from other aircraft systems.

This is the data the DEUs send to the EEC:

Total air temperature
Corrected static pressure
Total pressure
Calculated mach number
Greenwich mean time
Clock date
N1 target
Flight number
Bite data
Landing gear position
Start valve position
Engine run status of other engine
Databus status
Start switch position
Start lever position
Ignition switch position
Control mode switch position Air/ground
Flap position
Engine bleed switch position
ACS pack switch position
Cowl thermal anti-ice switch position
Wing anti-ice switch position Isolation valve position.



The Hard Alternate mode is used when the throttles are almost at idle - if in that phase of flight then an immediate engine response to throttle inputs is deemed necessary for flight safety (Soft Alternate mode makes sure the engine thrust does not have large changes when PT data is not valid.).