Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
General Maintenance Action
Human Factors; Aircraft; MEL; Weather; Manuals
This was a round trip event. 1) Ice detect 2 was deferred. 2) All company policies and MEL requirements were complied with at all times to the best of our abilities. During descent; we encountered icing conditions with an accompanying 'ICE' caution message. I turned on the Wing and Cowl Anti-ice switches. After approximately five minutes in icing conditions; we received wing overheat aural and visual warning messages. We complied with the QRH; landed; made a logbook write up and contacted Maintenance Control and Dispatch.Together we determined that the Right Inboard Temperature sensor had failed and that it was deferrable and followed the required MEL procedures under the direction of the Maintenance Supervisor. On climbout on the return flight we used the wing anti-ice again and it worked fine. However; after we turned it off and then on again 15 minutes later in the descent; we again received the wing overheat warning message. We complied with the QRH again. In light of all of the above; I am not convinced that the MEL that we deferred this under is actually a legal deferral. I don't think that enough troubleshooting was done in order to insure that the issue was as we thought. This is a concern as we accreted 'trace levels' of icing for a short time before we exited the clouds in the descent. (I expedited the descent to get out of the conditions).
The Captain of a CRJ-700 suspects the deferral of an ice detection system agreed upon between himself and Maintenance Control may not have been appropriate.