Narrative:

We were departing ord from the GA ramp on the last leg of a part 135 charter flight. We received our first taxi clearance from ground control approximately 15 mins after engine start. We were to be positioned for a runway 22L departure. Our initial taxi clearance was via txwys ll, then MM, to hold short of runway 27R. While awaiting the initial taxi clearance, and also while holding short of runway 27R, we heard a very busy ground controller handling an enormous number of aircraft with rapid and terse calls. The ground controller called us with further taxi instructions. However, just after calling our tail number, there was interference on the frequency from another aircraft that obscured, but did not obliterate the content of the clearance. I understood the clearance to 'cross runway 27L and contact the tower.' the PF's immediate reaction was to call out 'blocked.' since I thought I had heard the clearance correctly, my response to the PF was that I had heard the clearance. Without further discussion on our part, I read back the clearance to the ground controller. We paused and heard no response from the ground controller, so we taxied across the runway to the other side. During our postflt debrief, the PF stated that he took the lack of corrective response from the ground controller to mean that my readback had been correct. He also stated that he observed other aircraft crossing runway 27R further down the runway. He further stated that the instruction to first cross the runway and then contact tower seemed strange to him, but then reasoned that both ground and tower controllers were handling ground traffic along the various taxi rtes, and that we were in an area of intersecting and co-located diverging runway approach ends. Finally, he stated that because we have flown a lot of hours together, he was willing to trust that I had correctly understood the clearance. Upon reaching the other side, I changed frequencys and reported on the frequency to the tower controller. In response, the tower controller asked us if we had already crossed runway 27R and I replied in the affirmative. He let out a sigh and then stated that the clearance had been to hold short of the runway and contact tower, not to cross. I replied that I had understood we were cleared to cross. He then cleared us to taxi straight ahead and hold short of runway 32R. The rest of our taxi to runway 22L was without further incident or confusion. We departed ord approximately 1 hour after engine start. Contributing factors: 1) during our postflt discussion, we both agreed that long delays in receiving the taxi clrncs made us anxious to comply rapidly with our clrncs out of concern that even longer delays would ensue. 2) my own sense of urgency was also increased by knowledge of the taxi route we were on, combined with the volume of traffic and my own relative inexperience operating out of ord. The taxi route to runway 22L from our initial position was long and complex. 3) there was an unbelievable amount of taxiing traffic, huge lines of waiting traffic. The controllers were very hurried and terse, there were other instances of confusion on the frequency. It made me more likely to accept that I should act in spite of any doubt or suspicious communication. 4) the confign of multiple active runways necessitated numerous frequency changes. 5) we were tired, having worked many days out of the last 3 weeks with little or no scheduled time off. We were both anxious to get home. 6) my crewmate and I generally have a good working relationship. However, there are issues between us around regarding trust and respect that remain to be resolved. These flare up from time to time and, on a continual basis, block clear, complete, and effective communication. Actions/inactions: 1) I made the assumption that I had heard the clearance correctly in spite of the interference on the frequency instead of suspecting that the interference had made me misunderstand the clearance. In retrospect, I realize that I heard what I was hoping to hear. 2) I did not request that the controller repeat the clearance to be sure I had understood it correctly. I was unwilling to heed the sic's 'blocked' call and I did not solicit further discussion from him. 3) the sic did not verbalize his doubts nor assert his desire for clarification, but instead, chose to reason his way through his doubts and trust my apparent confidence. I also believe that he was unwilling to risk conflict by questioning my understanding of the transmission. 4) the ground controller did not correct an incorrect readback of a hold short clearance. Lessons learned/corrective actions: 1) this incident could have easily been avoided by not assuming an understanding of a garbled transmission and instead requesting repetition and clarification of the clearance -- particularly when the clearance involves the crossing of a runway. We both allowed ourselves to become somewhat complacent and rushed in this instance. 2) further, heeding the sic's concern over the blocked transmission and actively soliciting discussion with him would have also resulted in us both clearly hearing and understanding our taxi clearance. 3) we need to address to fatigue issues with our flight operations department. 4) my crewmate and I need to resolve our trust and respect issues.

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Original NASA ASRS Text

Title: FLT CREW OF C560 TAXI ACROSS RWY 27R AT ORD WITHOUT CLRNC.

Narrative: WE WERE DEPARTING ORD FROM THE GA RAMP ON THE LAST LEG OF A PART 135 CHARTER FLT. WE RECEIVED OUR FIRST TAXI CLRNC FROM GND CTL APPROX 15 MINS AFTER ENG START. WE WERE TO BE POSITIONED FOR A RWY 22L DEP. OUR INITIAL TAXI CLRNC WAS VIA TXWYS LL, THEN MM, TO HOLD SHORT OF RWY 27R. WHILE AWAITING THE INITIAL TAXI CLRNC, AND ALSO WHILE HOLDING SHORT OF RWY 27R, WE HEARD A VERY BUSY GND CTLR HANDLING AN ENORMOUS NUMBER OF ACFT WITH RAPID AND TERSE CALLS. THE GND CTLR CALLED US WITH FURTHER TAXI INSTRUCTIONS. HOWEVER, JUST AFTER CALLING OUR TAIL NUMBER, THERE WAS INTERFERENCE ON THE FREQ FROM ANOTHER ACFT THAT OBSCURED, BUT DID NOT OBLITERATE THE CONTENT OF THE CLRNC. I UNDERSTOOD THE CLRNC TO 'CROSS RWY 27L AND CONTACT THE TWR.' THE PF'S IMMEDIATE REACTION WAS TO CALL OUT 'BLOCKED.' SINCE I THOUGHT I HAD HEARD THE CLRNC CORRECTLY, MY RESPONSE TO THE PF WAS THAT I HAD HEARD THE CLRNC. WITHOUT FURTHER DISCUSSION ON OUR PART, I READ BACK THE CLRNC TO THE GND CTLR. WE PAUSED AND HEARD NO RESPONSE FROM THE GND CTLR, SO WE TAXIED ACROSS THE RWY TO THE OTHER SIDE. DURING OUR POSTFLT DEBRIEF, THE PF STATED THAT HE TOOK THE LACK OF CORRECTIVE RESPONSE FROM THE GND CTLR TO MEAN THAT MY READBACK HAD BEEN CORRECT. HE ALSO STATED THAT HE OBSERVED OTHER ACFT XING RWY 27R FURTHER DOWN THE RWY. HE FURTHER STATED THAT THE INSTRUCTION TO FIRST CROSS THE RWY AND THEN CONTACT TWR SEEMED STRANGE TO HIM, BUT THEN REASONED THAT BOTH GND AND TWR CTLRS WERE HANDLING GND TFC ALONG THE VARIOUS TAXI RTES, AND THAT WE WERE IN AN AREA OF INTERSECTING AND CO-LOCATED DIVERGING RWY APCH ENDS. FINALLY, HE STATED THAT BECAUSE WE HAVE FLOWN A LOT OF HRS TOGETHER, HE WAS WILLING TO TRUST THAT I HAD CORRECTLY UNDERSTOOD THE CLRNC. UPON REACHING THE OTHER SIDE, I CHANGED FREQS AND RPTED ON THE FREQ TO THE TWR CTLR. IN RESPONSE, THE TWR CTLR ASKED US IF WE HAD ALREADY CROSSED RWY 27R AND I REPLIED IN THE AFFIRMATIVE. HE LET OUT A SIGH AND THEN STATED THAT THE CLRNC HAD BEEN TO HOLD SHORT OF THE RWY AND CONTACT TWR, NOT TO CROSS. I REPLIED THAT I HAD UNDERSTOOD WE WERE CLRED TO CROSS. HE THEN CLRED US TO TAXI STRAIGHT AHEAD AND HOLD SHORT OF RWY 32R. THE REST OF OUR TAXI TO RWY 22L WAS WITHOUT FURTHER INCIDENT OR CONFUSION. WE DEPARTED ORD APPROX 1 HR AFTER ENG START. CONTRIBUTING FACTORS: 1) DURING OUR POSTFLT DISCUSSION, WE BOTH AGREED THAT LONG DELAYS IN RECEIVING THE TAXI CLRNCS MADE US ANXIOUS TO COMPLY RAPIDLY WITH OUR CLRNCS OUT OF CONCERN THAT EVEN LONGER DELAYS WOULD ENSUE. 2) MY OWN SENSE OF URGENCY WAS ALSO INCREASED BY KNOWLEDGE OF THE TAXI RTE WE WERE ON, COMBINED WITH THE VOLUME OF TFC AND MY OWN RELATIVE INEXPERIENCE OPERATING OUT OF ORD. THE TAXI RTE TO RWY 22L FROM OUR INITIAL POS WAS LONG AND COMPLEX. 3) THERE WAS AN UNBELIEVABLE AMOUNT OF TAXIING TFC, HUGE LINES OF WAITING TFC. THE CTLRS WERE VERY HURRIED AND TERSE, THERE WERE OTHER INSTANCES OF CONFUSION ON THE FREQ. IT MADE ME MORE LIKELY TO ACCEPT THAT I SHOULD ACT IN SPITE OF ANY DOUBT OR SUSPICIOUS COM. 4) THE CONFIGN OF MULTIPLE ACTIVE RWYS NECESSITATED NUMEROUS FREQ CHANGES. 5) WE WERE TIRED, HAVING WORKED MANY DAYS OUT OF THE LAST 3 WKS WITH LITTLE OR NO SCHEDULED TIME OFF. WE WERE BOTH ANXIOUS TO GET HOME. 6) MY CREWMATE AND I GENERALLY HAVE A GOOD WORKING RELATIONSHIP. HOWEVER, THERE ARE ISSUES BTWN US AROUND REGARDING TRUST AND RESPECT THAT REMAIN TO BE RESOLVED. THESE FLARE UP FROM TIME TO TIME AND, ON A CONTINUAL BASIS, BLOCK CLR, COMPLETE, AND EFFECTIVE COM. ACTIONS/INACTIONS: 1) I MADE THE ASSUMPTION THAT I HAD HEARD THE CLRNC CORRECTLY IN SPITE OF THE INTERFERENCE ON THE FREQ INSTEAD OF SUSPECTING THAT THE INTERFERENCE HAD MADE ME MISUNDERSTAND THE CLRNC. IN RETROSPECT, I REALIZE THAT I HEARD WHAT I WAS HOPING TO HEAR. 2) I DID NOT REQUEST THAT THE CTLR REPEAT THE CLRNC TO BE SURE I HAD UNDERSTOOD IT CORRECTLY. I WAS UNWILLING TO HEED THE SIC'S 'BLOCKED' CALL AND I DID NOT SOLICIT FURTHER DISCUSSION FROM HIM. 3) THE SIC DID NOT VERBALIZE HIS DOUBTS NOR ASSERT HIS DESIRE FOR CLARIFICATION, BUT INSTEAD, CHOSE TO REASON HIS WAY THROUGH HIS DOUBTS AND TRUST MY APPARENT CONFIDENCE. I ALSO BELIEVE THAT HE WAS UNWILLING TO RISK CONFLICT BY QUESTIONING MY UNDERSTANDING OF THE XMISSION. 4) THE GND CTLR DID NOT CORRECT AN INCORRECT READBACK OF A HOLD SHORT CLRNC. LESSONS LEARNED/CORRECTIVE ACTIONS: 1) THIS INCIDENT COULD HAVE EASILY BEEN AVOIDED BY NOT ASSUMING AN UNDERSTANDING OF A GARBLED XMISSION AND INSTEAD REQUESTING REPETITION AND CLARIFICATION OF THE CLRNC -- PARTICULARLY WHEN THE CLRNC INVOLVES THE XING OF A RWY. WE BOTH ALLOWED OURSELVES TO BECOME SOMEWHAT COMPLACENT AND RUSHED IN THIS INSTANCE. 2) FURTHER, HEEDING THE SIC'S CONCERN OVER THE BLOCKED XMISSION AND ACTIVELY SOLICITING DISCUSSION WITH HIM WOULD HAVE ALSO RESULTED IN US BOTH CLRLY HEARING AND UNDERSTANDING OUR TAXI CLRNC. 3) WE NEED TO ADDRESS TO FATIGUE ISSUES WITH OUR FLT OPS DEPT. 4) MY CREWMATE AND I NEED TO RESOLVE OUR TRUST AND RESPECT ISSUES.

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.