Narrative:

The captain was not feeling well, so he reclined his seat and lead his head back for a few mins. We had previously been on a vector heading for vhp and then cleared direct to flm. After passing flm, we were supposed to join J24 to hvq. I mistakenly read J24 to be a 124 degree course from flm. Actually, it is a 102 degree course. I saw that the captain had 124 set on his HSI (set from earlier and not yet changed) and that backed me up on my mistaken reading of the chart. At about the changeover point between flm-hvq, I went to set the inbound course to hvq and discovered the error. I notified the captain, we began to correct back to our course and notified ATC. ATC subsequently cleared us direct hvq. He made no indication to us that there was any loss of separation or problem. It is clear to me that an unusual situation that took one pilot out of the loop led to this navigation error. In accordance with SOP, I should have verbalized our new course after flm and allowed the captain to verify it, but I chose not to bother him while he wasn't feeling well. I will certainly do so in the future. Supplemental information from acn 511374: I felt sick, so I reclined my chair and laid my head back. After my rest (approximately 10 mins), I questioned the first officer on our routing and he said 'I think we are south of course.' we corrected back to course and advised ATC of the deviation. They hvq. After discussion with the first officer I found out he had mistaken the outbound course on J24 from flm with the outbound course from vhp. No separation clearance lost during deviation.

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Original NASA ASRS Text

Title: B737 CREW HAD TRACK DEV IN ZID CLASS A AIRSPACE.

Narrative: THE CAPT WAS NOT FEELING WELL, SO HE RECLINED HIS SEAT AND LEAD HIS HEAD BACK FOR A FEW MINS. WE HAD PREVIOUSLY BEEN ON A VECTOR HDG FOR VHP AND THEN CLRED DIRECT TO FLM. AFTER PASSING FLM, WE WERE SUPPOSED TO JOIN J24 TO HVQ. I MISTAKENLY READ J24 TO BE A 124 DEG COURSE FROM FLM. ACTUALLY, IT IS A 102 DEG COURSE. I SAW THAT THE CAPT HAD 124 SET ON HIS HSI (SET FROM EARLIER AND NOT YET CHANGED) AND THAT BACKED ME UP ON MY MISTAKEN READING OF THE CHART. AT ABOUT THE CHANGEOVER POINT BTWN FLM-HVQ, I WENT TO SET THE INBOUND COURSE TO HVQ AND DISCOVERED THE ERROR. I NOTIFIED THE CAPT, WE BEGAN TO CORRECT BACK TO OUR COURSE AND NOTIFIED ATC. ATC SUBSEQUENTLY CLRED US DIRECT HVQ. HE MADE NO INDICATION TO US THAT THERE WAS ANY LOSS OF SEPARATION OR PROB. IT IS CLR TO ME THAT AN UNUSUAL SIT THAT TOOK ONE PLT OUT OF THE LOOP LED TO THIS NAV ERROR. IN ACCORDANCE WITH SOP, I SHOULD HAVE VERBALIZED OUR NEW COURSE AFTER FLM AND ALLOWED THE CAPT TO VERIFY IT, BUT I CHOSE NOT TO BOTHER HIM WHILE HE WASN'T FEELING WELL. I WILL CERTAINLY DO SO IN THE FUTURE. SUPPLEMENTAL INFO FROM ACN 511374: I FELT SICK, SO I RECLINED MY CHAIR AND LAID MY HEAD BACK. AFTER MY REST (APPROX 10 MINS), I QUESTIONED THE FO ON OUR ROUTING AND HE SAID 'I THINK WE ARE S OF COURSE.' WE CORRECTED BACK TO COURSE AND ADVISED ATC OF THE DEV. THEY HVQ. AFTER DISCUSSION WITH THE FO I FOUND OUT HE HAD MISTAKEN THE OUTBOUND COURSE ON J24 FROM FLM WITH THE OUTBOUND COURSE FROM VHP. NO SEPARATION CLRNC LOST DURING DEV.

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.