Narrative:

While on the NDB approach to sdl, I was the PF. We proceeded outbound from avent to initiate our approach) after being released from the hold). The captain was working on his FMS while I flew. We completed our procedure turn, and the captain said we'd passed avent, descend to the next altitude on the approach (3400 ft, he had the approach plate and had set the altitude alerter). I began the descent. At approximately 3700 ft the controller gave us a low altitude alert, and ordered an immediate climb. I complied, and told the captain to verify our position as having passed avent. He agreed, as did both FMS's. We subsequently canceled IFR and landed without further incident. Contributing factors were a stressful duty day and the captain's confusion in operating the FMS.

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Original NASA ASRS Text

Title: A CL60 FO RPTED THAT THE CAPT LOST SITUATIONAL AWARENESS AND COMMANDED A DSCNT TOO EARLY DURING APCH TO PHX, CAUSING P50 TO ISSUE A LOW ALT ALERT.

Narrative: WHILE ON THE NDB APCH TO SDL, I WAS THE PF. WE PROCEEDED OUTBOUND FROM AVENT TO INITIATE OUR APCH) AFTER BEING RELEASED FROM THE HOLD). THE CAPT WAS WORKING ON HIS FMS WHILE I FLEW. WE COMPLETED OUR PROC TURN, AND THE CAPT SAID WE'D PASSED AVENT, DSND TO THE NEXT ALT ON THE APCH (3400 FT, HE HAD THE APCH PLATE AND HAD SET THE ALT ALERTER). I BEGAN THE DSCNT. AT APPROX 3700 FT THE CTLR GAVE US A LOW ALT ALERT, AND ORDERED AN IMMEDIATE CLB. I COMPLIED, AND TOLD THE CAPT TO VERIFY OUR POS AS HAVING PASSED AVENT. HE AGREED, AS DID BOTH FMS'S. WE SUBSEQUENTLY CANCELED IFR AND LANDED WITHOUT FURTHER INCIDENT. CONTRIBUTING FACTORS WERE A STRESSFUL DUTY DAY AND THE CAPT'S CONFUSION IN OPERATING THE FMS.

Data retrieved from NASA's ASRS site as of July 2007 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.