Narrative:

I was on an IFR flight from yum to sna. Primary en route navigation equipment LORAN, filed route of flight bza, ipl, mzb then direct, sna. I opted for this unusual routing because of convective activity in the region of julian stretching nebound. At arrival over ipl VOR it was clear that the WX over jli had moved northeast of our routing. The controller then cleared me 'direct jli, then rest of route unchanged.' it was my assumption then that after julian VOR I was cleared direct to sna after jli VOR. Upon arriving over jli VOR I selected direct sna and proceeded accordingly. After 9 mi past jli VOR the controller then requested I cross 10 mi east of ocn at 12000 ft. By now I was proceeding direct sna and the controller was stating that I proceed via ocn. My initial clearance was mzb direct sna. When I was cleared jli, rest of route unchanged I assumed jli direct sna. I made a radical heading change of 060 degrees to keep me clear of the upcoming camp pendleton restr airspace. The controller became concerned that I was unsure of my position. At this time I was trying to identify ocn VOR in the LORAN, as well as fly the aircraft. I recommend that when a revised clearance is issued the controller clarify in this instance when LORAN, GPS or INS are being used. I myself should have asked for clarification prior to arriving at julian VOR.

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Original NASA ASRS Text

Title: ROUTING CHANGE. ATC AND PLT MISCOM.

Narrative: I WAS ON AN IFR FLT FROM YUM TO SNA. PRIMARY ENRTE NAV EQUIP LORAN, FILED RTE OF FLT BZA, IPL, MZB THEN DIRECT, SNA. I OPTED FOR THIS UNUSUAL ROUTING BECAUSE OF CONVECTIVE ACTIVITY IN THE REGION OF JULIAN STRETCHING NEBOUND. AT ARR OVER IPL VOR IT WAS CLR THAT THE WX OVER JLI HAD MOVED NE OF OUR ROUTING. THE CTLR THEN CLRED ME 'DIRECT JLI, THEN REST OF RTE UNCHANGED.' IT WAS MY ASSUMPTION THEN THAT AFTER JULIAN VOR I WAS CLRED DIRECT TO SNA AFTER JLI VOR. UPON ARRIVING OVER JLI VOR I SELECTED DIRECT SNA AND PROCEEDED ACCORDINGLY. AFTER 9 MI PAST JLI VOR THE CTLR THEN REQUESTED I CROSS 10 MI E OF OCN AT 12000 FT. BY NOW I WAS PROCEEDING DIRECT SNA AND THE CTLR WAS STATING THAT I PROCEED VIA OCN. MY INITIAL CLRNC WAS MZB DIRECT SNA. WHEN I WAS CLRED JLI, REST OF RTE UNCHANGED I ASSUMED JLI DIRECT SNA. I MADE A RADICAL HDG CHANGE OF 060 DEGS TO KEEP ME CLR OF THE UPCOMING CAMP PENDLETON RESTR AIRSPACE. THE CTLR BECAME CONCERNED THAT I WAS UNSURE OF MY POS. AT THIS TIME I WAS TRYING TO IDENT OCN VOR IN THE LORAN, AS WELL AS FLY THE ACFT. I RECOMMEND THAT WHEN A REVISED CLRNC IS ISSUED THE CTLR CLARIFY IN THIS INSTANCE WHEN LORAN, GPS OR INS ARE BEING USED. I MYSELF SHOULD HAVE ASKED FOR CLARIFICATION PRIOR TO ARRIVING AT JULIAN VOR.

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.