Commercial Fixed Wing
Flight Crew Last 90 Days 280; Flight Crew Type 24000
Situational Awareness; Confusion
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Chart Or Publication; Human Factors
We were cleared for the VOR 31 Approach into AMA. In the FMC; there are two points called CF31 and FF31. On the approach plate; only FF31 is listed. We mistook CF31 for FF31 and descended too early. We broke out of the clouds about the same time ATC advised us of our mistake. We continued on in and landed uneventfully but embarrassed and much wiser. Spending more time briefing this approach might have helped. Renaming points CF31 and FF31 to something not as similar would help.
Captain briefed and flew the VOR to 31 in Amarillo 1;100 overcast. We both talked about not shooting a VOR approach in a long time. FMC had two points; CF31 which was 11 DME and FF31; which was 6 DME. Captain started down from 5;000 FT to DDA at CF31. We should have started down at FF31. [We] broke out visually with runway in sight. ATC called low altitude alert. We had the runway in sight and continued on visually and landed. No GPWS Warnings. This was a VOR DME approach. We did not back up the fixes by DME. This would have alleviated us starting down too early. Crew briefing should have put more emphasis on DME position.
Air carrier flight crew reported descending early on the VOR DME 31 to AMA; when the CF31 fix is confused with the FF31. The error is detected at about the same time ATC issues a low altitude alert. DME was not used to define the waypoints.