Narrative:

I was on a VFR cross country training flight from 9k4 to mci at XA3O. Before entering kansas city's class B airspace, I had my student call kansas city approach to get clearance into class B. Kansas city approach responded, 'cleared into class B at 4500 ft' and gave a squawk code. About 5 or 10 mins later, the approach controller came over frequency and told us, 'expect to cross mid field, enter a right downwind landing runway 19R.' we responded by reading back the clearance. About 5 mins later the approach controller asked us if we had the field in sight. After responding we had the airport in sight, the approach controller came back and said, 'resume your own navigation and contact the tower.' we responded with our readback and switched to tower. We then began our descent down to traffic pattern altitude. I interpreted the clearance 'resume your own navigation' as me being responsible to cross mid field and enter the right downwind at traffic pattern altitude. Upon reaching traffic pattern altitude, the tower controller came over frequency and asked, 'say altitude?' we responded by saying we were at traffic pattern altitude. The controller then responded that he thought we were at a higher altitude. There was no traffic conflict or any other danger brought about by our descent. It was simply a misunderstanding of what the term 'resume your own navigation' meant. I understood the phrase as being responsible for lateral navigation and also vertical navigation to put my plane in a position to enter a right downwind at the traffic pattern altitude. In order to correct the problem, I think there could have been more clarity within the clearance as to whether or not to maintain altitude. I also should have queried the controller as to whether or not a descent could be started. Thankfully, however, our descent to traffic pattern altitude did not cause any problems.

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Original NASA ASRS Text

Title: C172 PLT INSTRUCTOR, WITH STUDENT FLYING, ON A XCOUNTRY, DSNDED IN TO TFC PATTERN AT MCI BEFORE INSTRUCTED TO DO SO BY TWR IN CLASS B AIRSPACE.

Narrative: I WAS ON A VFR XCOUNTRY TRAINING FLT FROM 9K4 TO MCI AT XA3O. BEFORE ENTERING KANSAS CITY'S CLASS B AIRSPACE, I HAD MY STUDENT CALL KANSAS CITY APCH TO GET CLRNC INTO CLASS B. KANSAS CITY APCH RESPONDED, 'CLRED INTO CLASS B AT 4500 FT' AND GAVE A SQUAWK CODE. ABOUT 5 OR 10 MINS LATER, THE APCH CTLR CAME OVER FREQ AND TOLD US, 'EXPECT TO CROSS MID FIELD, ENTER A R DOWNWIND LNDG RWY 19R.' WE RESPONDED BY READING BACK THE CLRNC. ABOUT 5 MINS LATER THE APCH CTLR ASKED US IF WE HAD THE FIELD IN SIGHT. AFTER RESPONDING WE HAD THE ARPT IN SIGHT, THE APCH CTLR CAME BACK AND SAID, 'RESUME YOUR OWN NAV AND CONTACT THE TWR.' WE RESPONDED WITH OUR READBACK AND SWITCHED TO TWR. WE THEN BEGAN OUR DSCNT DOWN TO TFC PATTERN ALT. I INTERPED THE CLRNC 'RESUME YOUR OWN NAV' AS ME BEING RESPONSIBLE TO CROSS MID FIELD AND ENTER THE R DOWNWIND AT TFC PATTERN ALT. UPON REACHING TFC PATTERN ALT, THE TWR CTLR CAME OVER FREQ AND ASKED, 'SAY ALT?' WE RESPONDED BY SAYING WE WERE AT TFC PATTERN ALT. THE CTLR THEN RESPONDED THAT HE THOUGHT WE WERE AT A HIGHER ALT. THERE WAS NO TFC CONFLICT OR ANY OTHER DANGER BROUGHT ABOUT BY OUR DSCNT. IT WAS SIMPLY A MISUNDERSTANDING OF WHAT THE TERM 'RESUME YOUR OWN NAV' MEANT. I UNDERSTOOD THE PHRASE AS BEING RESPONSIBLE FOR LATERAL NAV AND ALSO VERT NAV TO PUT MY PLANE IN A POS TO ENTER A R DOWNWIND AT THE TFC PATTERN ALT. IN ORDER TO CORRECT THE PROB, I THINK THERE COULD HAVE BEEN MORE CLARITY WITHIN THE CLRNC AS TO WHETHER OR NOT TO MAINTAIN ALT. I ALSO SHOULD HAVE QUERIED THE CTLR AS TO WHETHER OR NOT A DSCNT COULD BE STARTED. THANKFULLY, HOWEVER, OUR DSCNT TO TFC PATTERN ALT DID NOT CAUSE ANY PROBS.

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.