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Pin Head
5th Oct 2015, 17:16
Hi

Why would the following symptoms possibly appear;

•No hydraulic pressure indication on the failed side
•Speed limit flag shown on the failed side
•Minimum maneuver speed and stick shaker band removed on the failed side •Both EEC ALTN lights illuminated.

Regards

Pin

HPIC
6th Oct 2015, 20:18
No hydraulic pressure indication on one side typically indicates DEU failure(DEU1 for HydA, DEU2 for HydB). You would probably have a CDS Fault annunciation as well(if on the ground).

I can see how DEU failure could cause the other issues as well, but I haven't personally noticed them in the incidents where I've had DEU issues. They were all on the ground, and MX reset the CB's for the DEU in question, waited about 3 minutes, and all was good. A total power down/power up would accomplish the same.

B737SFP
7th Oct 2015, 01:14
http://i.imgur.com/veSZIDu.png?1

Hope this scheme helps you understand the system...

Probably those items are listed as a consequence of a DEU failure, because DEUs gets data from numerous sources (such as ADIRU, thus leading to loss of minimum maneuvering & stick shaker band).

:ok:

Pin Head
7th Oct 2015, 03:49
Thanks

No hydraulic pressure indication displayed could be agreed as a display error by no LOW PRESSURE annunciation and the MFD (Lower display unit) page having no display. Combine both and you can assume you still have normal hydraulics. Also standby RUD would not have come on either?