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Old 30th Oct 2008, 06:44
  #2329 (permalink)  
justme69
 
Join Date: Aug 2008
Location: Canary Islands, Spain
Posts: 240
Just a quick note to clarify that, for whatever reason, the CIAIAC is strongly suspecting the failure of the R2-5 relay as oppossed to the strut gear sensor (as in a case described in this board) or the Left ground control circuit breaker (as in MAP case).

The main reason is probably the lack of evidence that the 30+ devices connected to the front wheel logic, including the 20 or so exclusive to the left wheel, failed the ground/air mode and, more importanly, that the Flight Data Recorder recorded a change of state from ground to air coming from the front wheel left sensor circuit on R2-12 shortly after VR was called, signalling a correct detection of the front wheels leaving the ground by the left wheel sensor circuit, to which R2-5 is also connected.

The R2-5 relay could have had an intermitent malfunction (i.e. a loose electrical connection, etc) and this would've only ultimately affected the ground/air logic for only two devices, the TOWS and the RAT probe anti-ice heater (because the other two "devices" also connected to R2-5, the AC x-tie & the radio rack venting were redundantly serviced from the right wheel sensor circuit through R2-8 and R2-4).

Most of this, especulation on my side.

Last edited by justme69; 2nd Nov 2008 at 04:50.
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