Narrative:

Aircraft X departed on a 160 heading after a practice approach looking for a clearance to txk. The clearance was issued to the pilot. The pilot was cleared to txk as filed; told to maintain 040. Then air carrier Y departed on a 180 heading. Air carrier Y was radar contacted and immediately given a traffic advisory; due to aircraft X turning on course to an approximately heading of 230. My trainer then keyed up and told aircraft X to immediately climb to 15;000 and later stopped him at a lower altitude. My trainer advised aircraft X that his last assigned heading was 160. Air carrier Y said that they had to descend due to the aircraft. I was unaware that when an aircraft was cleared as filed that they could immediately turn on course without being told to resume own navigation on course. However; after this occurrence I am completely aware of this. I believe the incident itself was enough to keep this type of event from happening again in the future.

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Original NASA ASRS Text

Title: LIT Controller receiving training issued a 'cleared as filed' instruction; the aircraft immediately turned on course; conflicting with other traffic prior to instructor intervention; the reporter noting lesson learned.

Narrative: Aircraft X departed on a 160 heading after a practice approach looking for a clearance to TXK. The clearance was issued to the pilot. The pilot was cleared to TXK as filed; told to maintain 040. Then Air Carrier Y departed on a 180 heading. Air Carrier Y was RADAR contacted and immediately given a traffic advisory; due to Aircraft X turning on course to an approximately heading of 230. My Trainer then keyed up and told Aircraft X to immediately climb to 15;000 and later stopped him at a lower altitude. My trainer advised Aircraft X that his last assigned heading was 160. Air Carrier Y said that they had to descend due to the aircraft. I was unaware that when an aircraft was cleared as filed that they could immediately turn on course without being told to resume own navigation on course. However; after this occurrence I am completely aware of this. I believe the incident itself was enough to keep this type of event from happening again in the future.

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.