Narrative:

The captain accepted taxi for an intersection departure from juliet with the understanding that better than 7000' of runway remained for takeoff on runway 12L. (We were informed that kilo was closed.) the captain inadvertently got off taxiway alpha on india which I pointed out to the captain. The captain responded for me to request a backtaxi, which he and I both understood to mean onto the runway to juliett, so the takeoff could begin at the proper place. I requested a backtaxi from ground control, who responded, 'that's approved,' or 'backtaxi approved.' the captain and I scanned for traffic on final approach and there was none. The captain then taxied onto the runway toward intersection J. We were then informed by ground that we were not supposed to be on the runway. The captain then took the radio and said that we had understood that our backtaxi down the runway was approved, and that the way we had understood our instructions. (Since no permission would have been required to turn around on india and take alpha to juliet.) the ground controller then instructed us to continue down the runway and exit at juliett. I reported us clear of the runway at J, at which time we were instructed to contact the tower for departure. The flight departed west/O incident and no further references were verbally made re: the missed communications or runway incursion. This seems like a classic case of being in too much of a hurry to communicate completely and concisely and making assumptions about what someone else has asked or instructed. Captain should have said: 'request a backtaxi down the runway.' if not, first officer should have said to the captain: 'down the runway?', and to ground: 'down the runway.' ground controller's instructions, 'backtaxi approved,' should have been questioned. Whether or not the crew used the term 'on the runway,' or, 'down the runway,' the ground controller should have been specific in his instructions (which he is taught as procedure). Ex: 'backtaxi is approved on the runway, exit at juliett and contact the tower.' or, ex: 'backtaxi is approved, make a left 180 onto alpha to juliett and contact the tower when ready for departure.'

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Original NASA ASRS Text

Title: SMT BACK TAXIED DOWN ACTIVE RWY WITHOUT CLRNC FROM TWR, MISUNDERSTANDING BETWEEN FLT CREW AND GND CTLR.

Narrative: THE CAPT ACCEPTED TAXI FOR AN INTXN DEP FROM JULIET WITH THE UNDERSTANDING THAT BETTER THAN 7000' OF RWY REMAINED FOR TKOF ON RWY 12L. (WE WERE INFORMED THAT KILO WAS CLOSED.) THE CAPT INADVERTENTLY GOT OFF TXWY ALPHA ON INDIA WHICH I POINTED OUT TO THE CAPT. THE CAPT RESPONDED FOR ME TO REQUEST A BACKTAXI, WHICH HE AND I BOTH UNDERSTOOD TO MEAN ONTO THE RWY TO JULIETT, SO THE TKOF COULD BEGIN AT THE PROPER PLACE. I REQUESTED A BACKTAXI FROM GND CTL, WHO RESPONDED, 'THAT'S APPROVED,' OR 'BACKTAXI APPROVED.' THE CAPT AND I SCANNED FOR TFC ON FINAL APCH AND THERE WAS NONE. THE CAPT THEN TAXIED ONTO THE RWY TOWARD INTXN J. WE WERE THEN INFORMED BY GND THAT WE WERE NOT SUPPOSED TO BE ON THE RWY. THE CAPT THEN TOOK THE RADIO AND SAID THAT WE HAD UNDERSTOOD THAT OUR BACKTAXI DOWN THE RWY WAS APPROVED, AND THAT THE WAY WE HAD UNDERSTOOD OUR INSTRUCTIONS. (SINCE NO PERMISSION WOULD HAVE BEEN REQUIRED TO TURN AROUND ON INDIA AND TAKE ALPHA TO JULIET.) THE GND CTLR THEN INSTRUCTED US TO CONTINUE DOWN THE RWY AND EXIT AT JULIETT. I RPTED US CLR OF THE RWY AT J, AT WHICH TIME WE WERE INSTRUCTED TO CONTACT THE TWR FOR DEP. THE FLT DEPARTED W/O INCIDENT AND NO FURTHER REFERENCES WERE VERBALLY MADE RE: THE MISSED COMS OR RWY INCURSION. THIS SEEMS LIKE A CLASSIC CASE OF BEING IN TOO MUCH OF A HURRY TO COMMUNICATE COMPLETELY AND CONCISELY AND MAKING ASSUMPTIONS ABOUT WHAT SOMEONE ELSE HAS ASKED OR INSTRUCTED. CAPT SHOULD HAVE SAID: 'REQUEST A BACKTAXI DOWN THE RWY.' IF NOT, F/O SHOULD HAVE SAID TO THE CAPT: 'DOWN THE RWY?', AND TO GND: 'DOWN THE RWY.' GND CTLR'S INSTRUCTIONS, 'BACKTAXI APPROVED,' SHOULD HAVE BEEN QUESTIONED. WHETHER OR NOT THE CREW USED THE TERM 'ON THE RWY,' OR, 'DOWN THE RWY,' THE GND CTLR SHOULD HAVE BEEN SPECIFIC IN HIS INSTRUCTIONS (WHICH HE IS TAUGHT AS PROC). EX: 'BACKTAXI IS APPROVED ON THE RWY, EXIT AT JULIETT AND CONTACT THE TWR.' OR, EX: 'BACKTAXI IS APPROVED, MAKE A LEFT 180 ONTO ALPHA TO JULIETT AND CONTACT THE TWR WHEN READY FOR DEP.'

Data retrieved from NASA's ASRS site as of August 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.