Narrative:

Small transport was checking out a water project near approach end of runway 31 and was advised to expect climb northwest of cmx when finished as traffic was holding southeast of cmx 5 mi at LOM for runway 31. Small transport stated they were completed with their inspection and they wanted to go to ssm. I cleared the aircraft to the cmx 310/020 maintain 4000. They misread the clearance. I repeated it back and they then read it back correctly. Traffic was 3 aircraft waiting for approach at cmx. I waited a little over 2 mins to ask for a report of small transport position and heading, thus giving them plenty of time to be en route to the cmx 310/020. They read back 2.3 northwest of cmx and heading 100 degree. I did not hear the heading, only the position. Given the time and situation I assumed they were flying away from cmx towards the cmx 310/020. Another aircraft was cleared for approach after I got small transport position 2.3 northwest of cmx (plenty of room). I then asked small transport's DME northwest of cmx so I could start them on a different heading and altitude towards new destination. They advised 1.5 southeast of cmx, which conflicts with the aircraft on approach. Small transport was later climbed to 5000 and was picked up on radar still over cmx almost 10 mins after original clearance. Pilot admitted on frequency being confused and thinking they were to remain southeast of cmx. No evasive action required. Lack of understanding of clearance and compliance. The aircraft's position and heading could have been double-checked. Supplemental information from acn 124975: we were about 5 NM west of the VOR heading east and not in radar contact. We were then issued a clearance to the htl 310 radial, 20 NM fix, 'fly direct'. My copilot read the clearance back as 'htl 310 radial, fly direct' and informed me to fly direct to the VOR which we were now almost at. I questioned the 20 NM fix and he clarified that center wanted us 20 NM northwest. By the time I turned the aircraft back (we were now just east of htl) to intercept the 310 radial outbnd, it became obvious to center that we were not where they thought we were and told us to fly a 310 heading. We were later informed (10 mins) to contact the watch supervisor, etc. Several mistakes were made. First, center issued a clearance before determining our actual position (including a climb). Second it was to a fix with no efc time on additional instructions and in the opposite direction of our filed destination. However, we should not have left VMC conditions even with a valid IFR clearance without clarification of a confusing clearance and assurance that center knew our position and intentions. I also, as PIC, should have questioned my copilot's readback if I was not clear on what center wanted. This could have been a more serious incident.

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Original NASA ASRS Text

Title: ZMP CTLR LOSES SEPARATION BETWEEN SMT UTILITY ACFT AND ANOTHER ON APCH INTO CMX IN A NON RADAR ENVIRONMENT DUE TO MISUNDERSTANDING OF CLRNC ON THE PART OF SMT PLT AND CTLR'S MISUNDERSTANDING OF PLT'S REPORTED DIRECTION OF FLT DURING HIS POSITION REPORT.

Narrative: SMT WAS CHECKING OUT A WATER PROJECT NEAR APCH END OF RWY 31 AND WAS ADVISED TO EXPECT CLIMB NW OF CMX WHEN FINISHED AS TFC WAS HOLDING SE OF CMX 5 MI AT LOM FOR RWY 31. SMT STATED THEY WERE COMPLETED WITH THEIR INSPECTION AND THEY WANTED TO GO TO SSM. I CLRED THE ACFT TO THE CMX 310/020 MAINTAIN 4000. THEY MISREAD THE CLRNC. I REPEATED IT BACK AND THEY THEN READ IT BACK CORRECTLY. TFC WAS 3 ACFT WAITING FOR APCH AT CMX. I WAITED A LITTLE OVER 2 MINS TO ASK FOR A REPORT OF SMT POSITION AND HDG, THUS GIVING THEM PLENTY OF TIME TO BE ENRTE TO THE CMX 310/020. THEY READ BACK 2.3 NW OF CMX AND HDG 100 DEG. I DID NOT HEAR THE HDG, ONLY THE POSITION. GIVEN THE TIME AND SITUATION I ASSUMED THEY WERE FLYING AWAY FROM CMX TOWARDS THE CMX 310/020. ANOTHER ACFT WAS CLRED FOR APCH AFTER I GOT SMT POSITION 2.3 NW OF CMX (PLENTY OF ROOM). I THEN ASKED SMT'S DME NW OF CMX SO I COULD START THEM ON A DIFFERENT HDG AND ALT TOWARDS NEW DEST. THEY ADVISED 1.5 SE OF CMX, WHICH CONFLICTS WITH THE ACFT ON APCH. SMT WAS LATER CLIMBED TO 5000 AND WAS PICKED UP ON RADAR STILL OVER CMX ALMOST 10 MINS AFTER ORIGINAL CLRNC. PLT ADMITTED ON FREQ BEING CONFUSED AND THINKING THEY WERE TO REMAIN SE OF CMX. NO EVASIVE ACTION REQUIRED. LACK OF UNDERSTANDING OF CLRNC AND COMPLIANCE. THE ACFT'S POSITION AND HDG COULD HAVE BEEN DOUBLE-CHECKED. SUPPLEMENTAL INFORMATION FROM ACN 124975: WE WERE ABOUT 5 NM W OF THE VOR HDG E AND NOT IN RADAR CONTACT. WE WERE THEN ISSUED A CLRNC TO THE HTL 310 RADIAL, 20 NM FIX, 'FLY DIRECT'. MY COPLT READ THE CLRNC BACK AS 'HTL 310 RADIAL, FLY DIRECT' AND INFORMED ME TO FLY DIRECT TO THE VOR WHICH WE WERE NOW ALMOST AT. I QUESTIONED THE 20 NM FIX AND HE CLARIFIED THAT CENTER WANTED US 20 NM NW. BY THE TIME I TURNED THE ACFT BACK (WE WERE NOW JUST E OF HTL) TO INTERCEPT THE 310 RADIAL OUTBND, IT BECAME OBVIOUS TO CENTER THAT WE WERE NOT WHERE THEY THOUGHT WE WERE AND TOLD US TO FLY A 310 HDG. WE WERE LATER INFORMED (10 MINS) TO CONTACT THE WATCH SUPVR, ETC. SEVERAL MISTAKES WERE MADE. FIRST, CENTER ISSUED A CLRNC BEFORE DETERMINING OUR ACTUAL POSITION (INCLUDING A CLIMB). SECOND IT WAS TO A FIX WITH NO EFC TIME ON ADDITIONAL INSTRUCTIONS AND IN THE OPPOSITE DIRECTION OF OUR FILED DEST. HOWEVER, WE SHOULD NOT HAVE LEFT VMC CONDITIONS EVEN WITH A VALID IFR CLRNC WITHOUT CLARIFICATION OF A CONFUSING CLRNC AND ASSURANCE THAT CENTER KNEW OUR POSITION AND INTENTIONS. I ALSO, AS PIC, SHOULD HAVE QUESTIONED MY COPLT'S READBACK IF I WAS NOT CLEAR ON WHAT CENTER WANTED. THIS COULD HAVE BEEN A MORE SERIOUS INCIDENT.

Data retrieved from NASA's ASRS site as of August 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.