Thank you very much for your posting.
All clear now.
Can you also post more details on the LEFT GND CTRL RELAYS B1-23 c/b?
Is it only one c/b or a whole set of them and this schematic is just simplified?
If it is only one, I guess it was in. It's the one ultimately feeding data flight recorder 31-31, which I'm guessing is the one recording the change of air/ground logic state (therefore, R2-212 was getting the 115VAC, sensed the oleo switch and changed the state of 31-31, so it was also working).
But to be certain, CIAIAC needs to clearly state the nature of the "front wheels flight mode state change" recorded by the FDR. Was it coming from R2-212 D contact?
- If so, the LEFT GND CTRL RELAYS c/b was probaly pushed in.
It would make sense then that only R2-5 was malfunctioning, as it only controls 4 devices, two of which are redundant on R2-6 (radio rack vent) and r2-8 (ac cross-tie). So only the RAT sensor heater and, amazingly and w/o redundancy, the Takeoff config warning, would be affected.
Therefore, little warning signs, hard to diagnoses w/o a good test, and would de-activate TOWS all by itself w/o any other problems (once RAT heater probe is disabled).
-If not, it's anybody's guess, as the +20 systems energized exclusively (i.e. not redundant from the right tire logic) by the 11 relays that this c/b services, are mostly "subtle" or "unusual" (heating, venting, etc) and most are only needed on flight and give probably little warning/signs on the ground. After all, the austrian Mapjet crew of OE-LMM in Lanzarote did take off clean with all those systems switched off ... if the MD-83 is any similar in that respect to the MD-82.
The schematic doesn't show Heating sensor 30-30 details. Could you please post one showing where the fuse that the technician removed would be in the path? Thanks.
Last edited by justme69; 21st Sep 2008 at 09:05.