Narrative:

We were proceeding north along J121 towards snow hill VOR with a clearance to continue along J121 to sea isle VOR and the cedar lake 2 arrival to phl. We were at FL230. The first officer was flying and upon crossing snow hill on J121 she set 353 degree in the course window thinking that we were already at sea isle VOR and 353 degree was the course to cedar lake for the arrival into phl. In fact we were only at snow hill and needed to continue on a 034 degree course out of snow hill to sea isle and then fly the 353 degree out of sea isle. Meantime, I had the correct inbound course and sea isle frequency tuned and set to continue along J121. My head was down writing engine data parameters in the aircraft logbook and did not notice the first officer initiate a left turn and off the airway. When I did look up due to center calling a descent clearance to us, I saw my course needle indicate off course to the left of the airway. By that time we were 40 degree off heading and in a bank. About the time I brought it to the first officer's attention, center was calling us and asking about our off airway situation. By that time we were probably about 5 miles off course. Center immediately issued a heading to correct and then cleared us direct to sea isle and on course. I do not believe that there was any conflict with other traffic. As far as human performance factors are concerned I do not know how the first officer managed to confuse snow hill with sea isle vors. I personally was involved with the logbook and out of the loop for a couple of minutes. Other than that, the only other possible explanation for a mistake like that is that it was the 4TH day of a 4 day trip. We flew alot the 3 days prior and had a short rest period the night before. Maybe fatigue had something to do with it. Callback conversation with reporter revealed the following: reporter did not add significantly with the callback. He cannot understand why the first officer did not recognize that his omni, which was tuned to the next VOR, did not show that VOR at the 12 O'clock position. He felt that, even though they had a short night sleep the night before, they were not tired, just not as sharp as they could have been.

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Original NASA ASRS Text

Title: MLG WAS FLOWN OUT THE WRONG RADIAL FROM SWL VOR.

Narrative: WE WERE PROCEEDING N ALONG J121 TOWARDS SNOW HILL VOR WITH A CLRNC TO CONTINUE ALONG J121 TO SEA ISLE VOR AND THE CEDAR LAKE 2 ARR TO PHL. WE WERE AT FL230. THE F/O WAS FLYING AND UPON XING SNOW HILL ON J121 SHE SET 353 DEG IN THE COURSE WINDOW THINKING THAT WE WERE ALREADY AT SEA ISLE VOR AND 353 DEG WAS THE COURSE TO CEDAR LAKE FOR THE ARR INTO PHL. IN FACT WE WERE ONLY AT SNOW HILL AND NEEDED TO CONTINUE ON A 034 DEG COURSE OUT OF SNOW HILL TO SEA ISLE AND THEN FLY THE 353 DEG OUT OF SEA ISLE. MEANTIME, I HAD THE CORRECT INBND COURSE AND SEA ISLE FREQ TUNED AND SET TO CONTINUE ALONG J121. MY HEAD WAS DOWN WRITING ENG DATA PARAMETERS IN THE ACFT LOGBOOK AND DID NOT NOTICE THE F/O INITIATE A L TURN AND OFF THE AIRWAY. WHEN I DID LOOK UP DUE TO CENTER CALLING A DSNT CLRNC TO US, I SAW MY COURSE NEEDLE INDICATE OFF COURSE TO THE L OF THE AIRWAY. BY THAT TIME WE WERE 40 DEG OFF HDG AND IN A BANK. ABOUT THE TIME I BROUGHT IT TO THE F/O'S ATTN, CTR WAS CALLING US AND ASKING ABOUT OUR OFF AIRWAY SIT. BY THAT TIME WE WERE PROBABLY ABOUT 5 MILES OFF COURSE. CTR IMMEDIATELY ISSUED A HDG TO CORRECT AND THEN CLRED US DIRECT TO SEA ISLE AND ON COURSE. I DO NOT BELIEVE THAT THERE WAS ANY CONFLICT WITH OTHER TFC. AS FAR AS HUMAN PERFORMANCE FACTORS ARE CONCERNED I DO NOT KNOW HOW THE F/O MANAGED TO CONFUSE SNOW HILL WITH SEA ISLE VORS. I PERSONALLY WAS INVOLVED WITH THE LOGBOOK AND OUT OF THE LOOP FOR A COUPLE OF MINUTES. OTHER THAN THAT, THE ONLY OTHER POSSIBLE EXPLANATION FOR A MISTAKE LIKE THAT IS THAT IT WAS THE 4TH DAY OF A 4 DAY TRIP. WE FLEW ALOT THE 3 DAYS PRIOR AND HAD A SHORT REST PERIOD THE NIGHT BEFORE. MAYBE FATIGUE HAD SOMETHING TO DO WITH IT. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: RPTR DID NOT ADD SIGNIFICANTLY WITH THE CALLBACK. HE CANNOT UNDERSTAND WHY THE F/O DID NOT RECOGNIZE THAT HIS OMNI, WHICH WAS TUNED TO THE NEXT VOR, DID NOT SHOW THAT VOR AT THE 12 O'CLOCK POSITION. HE FELT THAT, EVEN THOUGH THEY HAD A SHORT NIGHT SLEEP THE NIGHT BEFORE, THEY WERE NOT TIRED, JUST NOT AS SHARP AS THEY COULD HAVE BEEN.

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.