Question regarding to the B777 waste tank quantity indication system

[Asuada]

Hi guys,

I just having one question regarding to the aircraft (say B777) waste tank quantity indication system, I hope someone can provide me some detail technical support.

What are the reasons causes the aircraft waste tank quantity indication system showing "Full" when it is actually "Empty"?

Base on my understanding, It is usually due to the sensors failure or may be the LCM. But besides of that , is that any other reasons that could possibly constitute to this problem?

Best regards,

Asuada

[Plore]

Try rinsing the tanks a few times. It's usually 'excrement' thats sticking to the sensors.

[bvcu]

read the Boeing info, been going on for years, look in maint tips and fleet team digest. been a few mods over the years to improve things so not as common now.

[Asuada]

Hi guys,

when the the sensors and LCM fail to operate, it causes a full indication of the waste tank which causes the flushing system INOP.

But when the toilet is INOP due to some reasons say the vacuum blower or blockage of the tubing, is there any chance that could causes the indication system showing "Full"?

Also what are the reasons that could possibly causes the failure of LCM?