EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Workload
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Aircraft
Planed for the GUSHR Changed to the DRLLR arrivals. I was looking down at FMS and saw the screen flash and go blank. The backlight remained on; but there was no response to key presses. At the time we were on a heading for spacing with ZFW Center. I referenced enroute charts and IAH arrival charts looking for a suitable NON-RNAV option. I had the First Officer (FO) notify ATC and request the RIICE7 arrival as it was not an RNAV procedure. We operated the aircraft in degraded condition with green needles; the autopilot had a difficult time tracking VOR so was flown in heading mode with reference to RMI pointers and CDI. Fixes were verified with cross radial information loaded into RMU2/VOR2. We were assigned to cross RIICE at 16;000 feet; and I believe we were close on that fix; may have been off slightly due to slant range error on DME and VOR inaccuracy. IAH Approach took us just outside of RIICE and gave us vectors for the remainder of the arrival with a visual to 26L backed up with ILS.  Biggest threat was use of conventional nav and the workload associated with that. I worked to manage workload when fixes were close by selecting 'key' fixes that involved turns and altitudes to have cross radials loaded to reduce workload; once on vectors workload decreased significantly and I had the FO use that time to contact ops for gate and other lower priority tasks. Additionally ATC frequently tried to assign us direct to a fix that could not be navigated to without RNAV capability; but generally provided great assistance with ATIS information and other details to help offset our workload. Overall I believe the situation was managed effectively in spite of numerous threats and challenges during the RIICE arrival.  While I can not say for certain it is possible that an ACARS issue was involved in the CDU failure; and I will be filing a report to address that possibility. I do know that there is a workaround solution in the works for dual FMS aircraft to reset the ACARS DMU in flight from a functioning CDU; however I do not see any possibility of resetting on a single FMS unit other than a breaker reset that I was not comfortable performing in flight; but was the procedure performed by Maintenance control once at the gate.
EMB145 Captain experiences an FMC failure during descent and switches to radio navigation and a non RNAV arrival. This proves challenging and ATC eventually takes over with vectors.