An E-145 flight crew conducting an RNAV approach received low altitude alerts from the tower and egp...

Narrative:

While conducting the RNAV approach; we received conflicting vertical guidance from the FMS; while simultaneously receiving an altitude alert message from tower (potentially 400 ft below altitude). We immediately executed a missed approach. We then took our time on an extended downwind to reprogram the FMS; and completed the approach and landing uneventfully. It's important to note we followed all applicable procedures as per our training and RNAV tab.both flight crew members agreed upon setup of the FMS for the approach; and used the RNAV tab [in the handbook] to program the FMS. It would be beneficial to have a more structured 'checklist' for setting up an RNAV approach since we primarily conduct visual or ILS approaches. Also; it is worth mentioning that; while there were no ILS approaches currently available at ZZZ; there was a VOR that ATC suggested but for which we were not issued any approach plates and therefore had to use the RNAV again. Had the second approach resulted in another missed; we would have had to go to our alternate. If there is a way for the company to know when certain approaches will be unavailable; it would be helpful to have (at least temporarily) another form of approach to use that we may not otherwise need to carry.

Original NASA ASRS Text

Title: An E-145 flight crew conducting an RNAV approach received low altitude alerts from the Tower and EGPWS terrain warning inside of the final approach fix. They initiated a missed approach; reprogrammed the FMS and conducted a second approach uneventfully.

Narrative: While conducting the RNAV approach; we received conflicting vertical guidance from the FMS; while simultaneously receiving an altitude alert message from Tower (potentially 400 FT below altitude). We immediately executed a missed approach. We then took our time on an extended downwind to reprogram the FMS; and completed the approach and landing uneventfully. It's important to note we followed all applicable procedures as per our training and RNAV tab.Both flight crew members agreed upon setup of the FMS for the approach; and used the RNAV tab [in the handbook] to program the FMS. It would be beneficial to have a more structured 'checklist' for setting up an RNAV approach since we primarily conduct visual or ILS approaches. Also; it is worth mentioning that; while there were no ILS approaches currently available at ZZZ; there was a VOR that ATC suggested but for which we were not issued any approach plates and therefore had to use the RNAV again. Had the second approach resulted in another missed; we would have had to go to our alternate. If there is a way for the company to know when certain approaches will be unavailable; it would be helpful to have (at least temporarily) another form of approach to use that we may not otherwise need to carry.

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	1123801
Time
Date	201310
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	EMB ERJ 145 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

An E-145 flight crew conducting an RNAV approach received low altitude alerts from the tower and egpws terrain warning inside of the final approach fix. They initiated a missed approach; reprogrammed the FMS and conducted a second approach uneventfully.