Narrative:

While taxiing to runway 10C at pit for departure, we stayed with ground control as directed to a point just prior to the hold short line. An aircraft was then sequenced ahead of us and we were told to continue holding for the possibility of some other aircraft to go ahead of us. We were finally cleared to taxi to the runway. The first officer responded with a 'cleared into position and hold' which is also what I thought I heard. The fact that we were already so near the hold short line made this seem like a normal direction from tower. However, during the delay, I forgot we were still on ground control and not tower. Not realizing the anomaly, I taxied onto the runway (fortunately it wasn't being used for arrs so no conflict ever arose). Ground queried us and we soon realized we had never talked to tower. While I haven't listened to the tapes, I can't explain why the first officer and I both heard and understood a direction of 'position and hold.' I can say that as this was the last leg of a 10 hour day, fatigue did play a role in our momentary loss of situational awareness as far as which controller we were working with.

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Original NASA ASRS Text

Title: AN ACR MLG TAXIES ONTO ACTIVE RWY AT PIT, PA, WITHOUT TWR CLRNC. FLC HAS NO EXPLANATION FOR IT EXCEPT THEY WERE FATIGUED.

Narrative: WHILE TAXIING TO RWY 10C AT PIT FOR DEP, WE STAYED WITH GND CTL AS DIRECTED TO A POINT JUST PRIOR TO THE HOLD SHORT LINE. AN ACFT WAS THEN SEQUENCED AHEAD OF US AND WE WERE TOLD TO CONTINUE HOLDING FOR THE POSSIBILITY OF SOME OTHER ACFT TO GO AHEAD OF US. WE WERE FINALLY CLRED TO TAXI TO THE RWY. THE FO RESPONDED WITH A 'CLRED INTO POS AND HOLD' WHICH IS ALSO WHAT I THOUGHT I HEARD. THE FACT THAT WE WERE ALREADY SO NEAR THE HOLD SHORT LINE MADE THIS SEEM LIKE A NORMAL DIRECTION FROM TWR. HOWEVER, DURING THE DELAY, I FORGOT WE WERE STILL ON GND CTL AND NOT TWR. NOT REALIZING THE ANOMALY, I TAXIED ONTO THE RWY (FORTUNATELY IT WASN'T BEING USED FOR ARRS SO NO CONFLICT EVER AROSE). GND QUERIED US AND WE SOON REALIZED WE HAD NEVER TALKED TO TWR. WHILE I HAVEN'T LISTENED TO THE TAPES, I CAN'T EXPLAIN WHY THE FO AND I BOTH HEARD AND UNDERSTOOD A DIRECTION OF 'POS AND HOLD.' I CAN SAY THAT AS THIS WAS THE LAST LEG OF A 10 HR DAY, FATIGUE DID PLAY A ROLE IN OUR MOMENTARY LOSS OF SITUATIONAL AWARENESS AS FAR AS WHICH CTLR WE WERE WORKING WITH.

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.