Narrative:

We were flying a scheduled flight from anchorage, ak, to kenai, ak. We departed anchorage IFR and 10 mins into the flight were switched to center and given a vector to intercept the kenai localizer. Once established inbound, and within the 15 mi stepdown (at which we were good down to 1300 ft), I descended from our MEA of 2000 ft, down to 1300 ft. At approximately 13 DME, center called and said to 'maintain 2000 ft until established on published portion of approach, cleared for ILS runway 19 kenai,' at which point we realized that we had not been cleared for the approach when we initiated our descent. It was the end of our day and I think that we descended early because we are usually always cleared at that point, and as the first officer flying, I think I talked the captain into letting me descend by noting that we were within 15 mi and good down to 1300 ft. He agreed, and we both let the fact that center had not cleared us yet slip by, partly by inattn, partly by being creatures of habit, and being used to having approach clearance at that stage of the approach. There was no other traffic in the area, so safety was not compromised, but this incident flagged our attention to the need for verification and concurrence between both crew members as to what we are cleared to do.

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Original NASA ASRS Text

Title: FLC OF DHC6 TWIN OTTER DSNDS BELOW MEA BELIEVING THAT THEY HAVE BEEN CLRED FOR APCH. CTR THEN CLRED THEM FOR APCH AND THEY REALIZED THE ERROR.

Narrative: WE WERE FLYING A SCHEDULED FLT FROM ANCHORAGE, AK, TO KENAI, AK. WE DEPARTED ANCHORAGE IFR AND 10 MINS INTO THE FLT WERE SWITCHED TO CTR AND GIVEN A VECTOR TO INTERCEPT THE KENAI LOC. ONCE ESTABLISHED INBOUND, AND WITHIN THE 15 MI STEPDOWN (AT WHICH WE WERE GOOD DOWN TO 1300 FT), I DSNDED FROM OUR MEA OF 2000 FT, DOWN TO 1300 FT. AT APPROX 13 DME, CTR CALLED AND SAID TO 'MAINTAIN 2000 FT UNTIL ESTABLISHED ON PUBLISHED PORTION OF APCH, CLRED FOR ILS RWY 19 KENAI,' AT WHICH POINT WE REALIZED THAT WE HAD NOT BEEN CLRED FOR THE APCH WHEN WE INITIATED OUR DSCNT. IT WAS THE END OF OUR DAY AND I THINK THAT WE DSNDED EARLY BECAUSE WE ARE USUALLY ALWAYS CLRED AT THAT POINT, AND AS THE FO FLYING, I THINK I TALKED THE CAPT INTO LETTING ME DSND BY NOTING THAT WE WERE WITHIN 15 MI AND GOOD DOWN TO 1300 FT. HE AGREED, AND WE BOTH LET THE FACT THAT CTR HAD NOT CLRED US YET SLIP BY, PARTLY BY INATTN, PARTLY BY BEING CREATURES OF HABIT, AND BEING USED TO HAVING APCH CLRNC AT THAT STAGE OF THE APCH. THERE WAS NO OTHER TFC IN THE AREA, SO SAFETY WAS NOT COMPROMISED, BUT THIS INCIDENT FLAGGED OUR ATTN TO THE NEED FOR VERIFICATION AND CONCURRENCE BTWN BOTH CREW MEMBERS AS TO WHAT WE ARE CLRED TO DO.

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.