PJ2,
Thank You.
Unfortunately, the lav thing is going to keep cropping up.
Here's the deal for the unknowing:
#1: The message may be considered spurious, the VSC has forgotten how many lavs are attached or where they are. Everything still works.
#2: The toilet system is a vacuum system. Below 16000 feet, there is a vacuum generator back at the waste tanks which creates the suction to remove the effluvia. Above 16000 feet, the job is done by differential pressure.
#3: When you press the flush button, the vacuum system controller takes a quick peek to make sure no other toilet is flushing and if the answer is no, the flush valve (a guillotine type valve, best description, sorry) slides open and voila! If the answer is yes, it delays your flush until the other flush is complete. That's all.
#4: There are no "flush motors" behind the toilet. Nothing dangerous or scary there.
#5: If the vacuum generator still manages to run above 16000 feet, the cockpit will receive many many calls from the gals because the floor will vibrate beneath the floor of the aft galley.
Now that EVERYONE knows how the toilets work, can we move along and try to figure out how a perfectly good airplane managed to find itself in what has to be considered the worst possible weather to find oneself in alternate law?
It's obvious from the ACARS data that they lost more than one ADR. This begets a cascade of failures that are a RESULT of the ADR loss. There is no indication that the failures were independent.
Failure messages are not necessarily chronological. Deciphering the ACARS data is a skill, a black art if you will. Some would troubleshoot the lav faults. Others may look at other faults.
Some have suggested that the crew kicked the tail off.
When the RTL goes, it freezes (hard) at the moment of failure. The range is 31.6º ≤150 CAS to 4º ≥ 350 CAS. Figure the speed when the failure occurred and imagine having enough authority to damage the tail from there. As previously stated, you do get it back at slat extension.
What's left?
TCAS goes with the loss of all 3 ADR's or IR1. If you can get IR1 to work in ATT mode, you can get TCAS back, but not if you are missing 3 ADR's.
How did that happen?
The NAV ADR DISAGREE message.
The message is triggered by the PRIMS either because YOU switched off an ADR and the PRIM(s) detected a difference between the remaining two, or the PRIM(s) detected an error in one ADR and disregarded it.
The A/P and A/T messages?
This warning is displayed only for involuntary disconnection. That will happen when you lose your air data.
Last but not least, the pressurization message. When you lose all three ADR's you lose CPC 1 and 2, so cab press is manual.
Imagine yourself in monster turbulence, lots of red messages in front of you, possibly getting your head knocked on the panel. Are you worrying about cabin pressure?
Is anyone detecting a theme here?
Apologies if I ranted too long or appear snarky, but I'm just saying...
PB