The captain of a crj-700 suspects the deferral of an ice detection system agreed upon between himsel...

Narrative:

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).

Original NASA ASRS Text

Title: 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.

Narrative: 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).

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1082983
Time
Date	201304
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Regional Jet 700 ER/LR (CRJ700)
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	Ice/Rain Protection System
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence

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.