Narrative:

We were operating to ont. And filed and cleared for the KARLB2 arrival into ont. At cruise altitude and prior to descent; center issued a clearance to proceed direct to coazt and to cross coazt at 16;000 feet. As pilot monitoring; I read back the clearance fully; to proceed direct to coazt and cross coazt at 16;000 feet. We started the descent a bit early due to some turbulence and in the descent center asked if we were going to be able to make our altitude restriction at 16;000 feet. I responded that we would be able to make coazt at 16;000 feet and he told us that we had been cleared to cross goatz at 16;000 feet; not coazt. My first officer and I believed we both heard 'cleared to coazt; and cross coazt at 16;000 feet' and after initially reading that back we were not queried by ATC. So I assume that ATC thought we said goatz. We were then given a new clearance to proceed direct to poxku and descend to 7;000 feet. The rest of the flight was uneventful. I believe this deviation was due in part to having two fixes on the same arrival being so similarly named. Even with our noise reducing headsets it was very difficult to tell the difference between goatz and coazt. I would strongly urge one of these fixes to be renamed to prevent further miscommunication and deviation like ours.

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Original NASA ASRS Text

Title: Air Carrier flight crew reported navigating to the wrong fix due to similar sounding fixes (GOATZ and COAZT) on the same RNAV STAR.

Narrative: We were operating to ONT. And filed and cleared for the KARLB2 arrival into ONT. At cruise altitude and prior to descent; Center issued a clearance to proceed direct to COAZT and to cross COAZT at 16;000 feet. As Pilot Monitoring; I read back the clearance fully; to proceed direct to COAZT and cross COAZT at 16;000 feet. We started the descent a bit early due to some turbulence and in the descent Center asked if we were going to be able to make our altitude restriction at 16;000 feet. I responded that we would be able to make COAZT at 16;000 feet and he told us that we had been cleared to cross GOATZ at 16;000 feet; not COAZT. My First Officer and I believed we both heard 'cleared to COAZT; and cross COAZT at 16;000 feet' and after initially reading that back we were not queried by ATC. So I assume that ATC thought we said GOATZ. We were then given a new clearance to proceed direct to POXKU and descend to 7;000 feet. The rest of the flight was uneventful. I believe this deviation was due in part to having two fixes on the same arrival being so similarly named. Even with our noise reducing headsets it was very difficult to tell the difference between GOATZ and COAZT. I would strongly urge one of these fixes to be renamed to prevent further miscommunication and deviation like ours.

Data retrieved from NASA's ASRS site 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.