Narrative:

We were on an instrument flight plan approaching deland, fl, for landing. WX was VMC above a scattered/broken layer with good visibility beneath. Although good enough for a visual arrival, we elected to do an instrument approach due to rain showers in the area. We were told to expect the VOR runway 23 and were cleared direct to omn VOR, the IAF. Approaching the VOR we were surprised to be given a vector, which would have placed us inside the VOR on the final approach course. We had to re-look at the approach to determine when we would be legal to descend out of 4000 ft, the VOR minimum crossing altitude. Moments later, we got a frequency change to a new approach controller, who immediately cleared us back to the omn VOR. We again had to discuss the descent profile. By this time we were passing over the VOR, so we set the altitude alerter for the next segment altitude of 1600 ft and the autoplt began a slow descent. The controller must have noticed us descending, as he stated we were not yet cleared for the approach. We climbed back to 4000 ft, and were immediately cleared for the approach, which was completed uneventfully. This was a well rested, well trained, experienced crew. The problem was rapidly changing clrncs, a change to a new controller frequency just outside the IAF, and a crew rushed to change their pre-briefed plan. Although we were just told to expect the approach, in the confusion we both proceeded as if we had been cleared, and upon passing the VOR felt we had to start down immediately. It could have been avoided by eliminating multiple ATC clearance revisions while close to the IAF, and by more attentiveness on the part of the crew.

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Original NASA ASRS Text

Title: EXPECTING A VOR APCH A DSCNT IS BEGUN WITHOUT CLRNC WHEN A VECTOR IS GIVEN THAT APPEARED TO BE BYPASSING THE IAF.

Narrative: WE WERE ON AN INST FLT PLAN APCHING DELAND, FL, FOR LNDG. WX WAS VMC ABOVE A SCATTERED/BROKEN LAYER WITH GOOD VISIBILITY BENEATH. ALTHOUGH GOOD ENOUGH FOR A VISUAL ARR, WE ELECTED TO DO AN INST APCH DUE TO RAIN SHOWERS IN THE AREA. WE WERE TOLD TO EXPECT THE VOR RWY 23 AND WERE CLRED DIRECT TO OMN VOR, THE IAF. APCHING THE VOR WE WERE SURPRISED TO BE GIVEN A VECTOR, WHICH WOULD HAVE PLACED US INSIDE THE VOR ON THE FINAL APCH COURSE. WE HAD TO RE-LOOK AT THE APCH TO DETERMINE WHEN WE WOULD BE LEGAL TO DSND OUT OF 4000 FT, THE VOR MINIMUM XING ALT. MOMENTS LATER, WE GOT A FREQ CHANGE TO A NEW APCH CTLR, WHO IMMEDIATELY CLRED US BACK TO THE OMN VOR. WE AGAIN HAD TO DISCUSS THE DSCNT PROFILE. BY THIS TIME WE WERE PASSING OVER THE VOR, SO WE SET THE ALT ALERTER FOR THE NEXT SEGMENT ALT OF 1600 FT AND THE AUTOPLT BEGAN A SLOW DSCNT. THE CTLR MUST HAVE NOTICED US DSNDING, AS HE STATED WE WERE NOT YET CLRED FOR THE APCH. WE CLBED BACK TO 4000 FT, AND WERE IMMEDIATELY CLRED FOR THE APCH, WHICH WAS COMPLETED UNEVENTFULLY. THIS WAS A WELL RESTED, WELL TRAINED, EXPERIENCED CREW. THE PROB WAS RAPIDLY CHANGING CLRNCS, A CHANGE TO A NEW CTLR FREQ JUST OUTSIDE THE IAF, AND A CREW RUSHED TO CHANGE THEIR PRE-BRIEFED PLAN. ALTHOUGH WE WERE JUST TOLD TO EXPECT THE APCH, IN THE CONFUSION WE BOTH PROCEEDED AS IF WE HAD BEEN CLRED, AND UPON PASSING THE VOR FELT WE HAD TO START DOWN IMMEDIATELY. IT COULD HAVE BEEN AVOIDED BY ELIMINATING MULTIPLE ATC CLRNC REVISIONS WHILE CLOSE TO THE IAF, AND BY MORE ATTENTIVENESS ON THE PART OF THE CREW.

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.