UNAUTH TKOF IN A NIGHT OP. UNAUTH TKOF ON CLOSED RWY.

Narrative

ON A NIGHT TRAINING FLT WITH A PVT PLT WORKING ON HIS COMMERCIAL CERTIFICATE; I WANTED TO SEE HOW MY STUDENT WOULD CONDUCT HIMSELF ENTERING THE PATTERN AND LNDG AT AN UNFAMILIAR ARPT. MY ORIGINAL INTENTION WAS TO DO A STOP- AND-GO AND THEN RETURN TO OUR HOME ARPT. THE ARPT'S TWR WAS CLOSED; SO MY STUDENT MADE ALL THE APPROPRIATE CALLS ON THE CTAF. WHEN TURNING BASE; MY STUDENT RPTED OUR INTENTIONS WERE TO DO A TOUCH-AND-GO. (NOTE: THERE WERE NO OTHER ACFT ON FREQ). WE THEN RECEIVED A RADIO CALL (THAT I ASSUME WAS FROM THE ARPT MGR OR NOISE ABATEMENT OFFICE ON THE GND) STATING THAT THERE WERE NO REPEATED TOUCH AND GO'S ALLOWED AFTER XA00 LCL; BUT IF WE WERE GOING TO DO ONLY 1; IT WOULD BE OK. MY STUDENT THEN JUST REACTED AND SAID WE WOULD DO A FULL STOP AND TAXI BACK; TO WHICH THE GND CALLER RPTED THAT WOULD BE FINE. I DECIDED TO GO ALONG WITH THIS BECAUSE I THOUGHT IT WOULD BE A GOOD EXPERIENCE TAXIING AT NIGHT AT AN UNFAMILIAR ARPT WITHOUT THE LUXURY OF A PROGRESSIVE TAXI FROM GND CTL. CONCORD-BUCHANAN FIELD OFFERS A CHALLENGING NIGHT DEST BECAUSE IT HAS 4 RWYS (2 SETS OF PARALLELS WITH ALMOST IDENTICAL DIMENSIONS) WITH ONLY 50 DEGS OF HDG DIFFERENCE BTWN THE PARALLELS. WHEN THE TWR OPERATES; 3 RWYS ARE LIGHTED; AND ORIENTATION TO THE APPROPRIATE RWY AND PROPER ENTRY INTO THE PATTERN ARE DIFFICULT. BUT WITH THE TWR CLOSED; ONLY 1 RWY IS LIGHTED AND THE 3 OTHERS ARE NOTAM CLOSED AND UNLIGHTED -- THIS PRESENTS TAXI PROBS. WE HAD A NORMAL LNDG ON THE PROPER RWY 19R AND TAXIED CLR. IN ORDER TO TAXI BACK TO THE APCH END OF RWY 19R; ONE MUST CROSS RWYS 14R AND 14L. UNFORTUNATELY; NOT HAVING PLANNED ON TAXIING AT CONCORD; WE DID NOT HAVE AN ARPT DIAGRAM WITH US. UPON TAXIING BACK; WE PASSED ONE SMALL RWY AND EVENTUALLY FOUND OURSELVES ON THE MIDDLE OF ANOTHER BIG RWY. AT THIS POINT; THERE WERE NO TXWY SIGNS IMMEDIATELY VISIBLE; AND MY STUDENT NOTICED A SIGN ON THE L SIDE OF THE RWY DEPICTING 19R-01L; AND I NOTICED WIDELY SPACED WHITE LIGHTS ALONG THE SIDE OF THE RWY. WE WERE A LITTLE DISORIENTED BY THE SIGNS AND RWY MARKINGS WHEN MY STUDENT SAID; 'THIS MUST BE IT;' MEANING OUR RWY. I FELT AT THIS POINT THAT WE WERE ON AN ACTIVE RWY AND DIDN'T WANT TO LINGER OR WANDER. WANTING TO PROCEED WITHOUT DELAY; I SAID; 'LET'S GO.' ON THE TKOF ROLL; I NOTICED THAT THOSE WHITE EDGE LIGHTS WERE QUICKLY GONE AND ONCE WE WERE AIRBORNE I KNEW WE HAD DONE SOMETHING WRONG. I WASN'T UNTIL BACK ON THE GND AT OUR HOME ARPT WHERE I LOOKED AT AN ARPT DIAGRAM AND FIGURED OUT THAT WE HAD TAKEN OFF OF CLOSED RWY 14L. IT WAS CLR OUR TKOF ROLL STARTED JUST PRIOR TO WHERE RWYS 19R AND 14L INTERSECT. THE SIGN MY STUDENT POINTED OUT WAS A RWY HOLDING POS SIGN AND THE WHITE EDGE LIGHTS WERE FROM RWY 19R AT THE INTXN THAT MUST HAVE BEEN JUST AHEAD OF US. THE ERROR FORTUNATELY HAD NO SAFETY DANGERS. THE RWY WAS CLOSED BECAUSE THE TWR WAS CLOSED AND THE RWY LIGHTS REACTIVATED; WE HAD PLENTY OF RWY FOR OUR TKOF WITH NO OBSTRUCTIONS IN OUR PATH. BUT; I HAVE CONTEMPLATED POSSIBLE ACTIONS THAT MIGHT HAVE PREVENTED THIS MISHAP. BETTER PLANNING WITH AN ARPT DIAGRAM HANDY WOULD HAVE HELPED. DOING A PROPER TKOF CHK INCLUDING LINING UP THE HDG INDICATOR; MAGNETIC COMPASS; AND RWY HDG WOULD HAVE CAUGHT THE ERROR. BEING MORE FAMILIAR WITH ARPT RWY AND TAXI MARKINGS; SIGNS; AND LIGHTS MIGHT ALSO HAVE HELPED. I THINK IF I HAD BEEN MORE PATIENT AND DELIBERATE; I MIGHT HAVE GOTTEN MY BEARINGS BETTER BEFORE I HAVE THE 'LET'S GO.' I ALSO BELIEVE THAT THE TAXI MARKINGS; IN PARTICULAR; COULD HAVE BEEN BETTER LIGHTED AND MORE VISIBLE. XING A 150 FT WIDE RWY WITH NO TAXI LIGHTS OR CLR SIGNS IS DISORIENTING. I KNOW IT'S NO NEW REVELATION THAT TAXING AT NIGHT CAN BE ONE OF THE MOST DIFFICULT PARTS OF A NIGHT FLT; BUT I HOPE THE FAA CONTINUES TO DO MORE TO MAKE IT EASIER FOR PLTS TO NOT FEEL SO IN THE DARK WHEN TRYING TO FIND THEIR WAY AROUND AN ARPT AT NIGHT.