Narrative:

An A319 called for taxi and was issued instructions for runway 9. He stated that he needed 4R so his instructions were amended and a hold short of juliet taxiway was issued. The pilot read back the hold short point correctly. As the pilot approached bravo he was instructed to make a right turn behind an airbus on bravo. He had stopped so I wanted to make sure he made the turn so the other traffic waiting for him could keep moving as well. He replied to me that he would follow the airbus. I did not hear him say the word 'follow' or else I would have restated his instructions. At no time were the hold short instructions amended. The A319 turned on to bravo taxiway and was issued a frequency change to tower. He acknowledged the change correctly then proceeded to follow the airbus past juliet taxiway all the way around to 4R. Tower tried to contact him but he never answered. Local control east was able to raise him but by the time we got him a corporate jet had been sent around that was a mile final for 4L. No loss of separation occurred but the controller was concerned that they couldn't get a hold of the A319 and his slow taxi might cause the asde-X to go off with the 4L arrival. I am very careful of the word 'follow' and I never use the word in my transmissions as a best practice. I will be more careful with listening for that word or any other word in my pilot controller communications that may lead a pilot to believe that their hold short is no longer in effect. I did not use the word 'follow'; the pilot stated he would follow the airbus when I told him to make a right turn on bravo behind the airbus.

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Original NASA ASRS Text

Title: BOS Controller described a go around event caused by unclear taxi communications provided to a taxiing air carrier.

Narrative: An A319 called for taxi and was issued instructions for Runway 9. He stated that he needed 4R so his instructions were amended and a hold short of Juliet Taxiway was issued. The pilot read back the hold short point correctly. As the pilot approached Bravo he was instructed to make a right turn behind an Airbus on Bravo. He had stopped so I wanted to make sure he made the turn so the other traffic waiting for him could keep moving as well. He replied to me that he would follow the Airbus. I did not hear him say the word 'follow' or else I would have restated his instructions. At no time were the hold short instructions amended. The A319 turned on to Bravo Taxiway and was issued a frequency change to Tower. He acknowledged the change correctly then proceeded to follow the Airbus past Juliet Taxiway all the way around to 4R. Tower tried to contact him but he never answered. Local Control East was able to raise him but by the time we got him a corporate jet had been sent around that was a mile final for 4L. No loss of separation occurred but the Controller was concerned that they couldn't get a hold of the A319 and his slow taxi might cause the ASDE-X to go off with the 4L arrival. I am very careful of the word 'follow' and I never use the word in my transmissions as a best practice. I will be more careful with listening for that word or any other word in my pilot controller communications that may lead a pilot to believe that their hold short is no longer in effect. I did not use the word 'follow'; the pilot stated he would follow the Airbus when I told him to make a right turn on Bravo behind the Airbus.

Data retrieved from NASA's ASRS site as of April 2012 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.