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.