Narrative:

On sep/thu/96, I was directly involved in an operational error that occurred at XA41 am mdt. The incident in question occurred immediately after I assumed control of the local/ground position. C130 had just been cleared for takeoff on runway 35 by the previous controller and prior to the position relief briefing. After the briefing, I assumed control of the local/ground position. A ground vehicle requested clearance to cross runway 35 at mid field. Under the assumption the C130 was not yet cleared for takeoff, I cleared the vehicle to cross runway 35. The C130 then advised of the aborted takeoff due to a vehicle on the runway. The position relief briefing that I received was complete and concise. Traffic was light, with only 3 aircraft on frequency and a ground vehicle. The C130 brought the incident to my attention by advising his aborted takeoff. My perception of the traffic picture was that the C130 did not have a takeoff clearance. A hearback problem during the position relief briefing played a contributing factor in the incident. The perception of what I heard during the briefing, was in actuality, not what was communicated. In addition, a breakdown in visual scanning techniques also played a role. Had I scanned the runway visually prior to issuing the crossing clearance, it would have alerted me that an aircraft was in position for takeoff. Lack of awareness, rather than poor judgement were primary factors in the incident. On that day, prior to reporting for work, I considered requesting sick leave due to a physical illness. My decision was to report for work. Cognitive awareness was somewhat reduced by this condition and I overestimated my abilities to function under these circumstances. In future, establishing good readback/hearback techniques and incorporating consistent scanning techniques, I believe will help eliminate future incidents such as these. Utilizing sick leave that is provided should be encouraged and utilized when physiologically one is not functioning 100 percent.

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Original NASA ASRS Text

Title: ATCT CTLR WORKING LCL AND GND CTL POS COMBINED AND HAD JUST ASSUMED THOSE POS, CLRED A VEHICLE TO CROSS THE ACTIVE RWY AS A C130 WAS STARTING HIS TKOF ROLL. THE C130 ADVISED TWR HE WAS ABORTING TKOF DUE TO VEHICLE ON THE RWY.

Narrative: ON SEP/THU/96, I WAS DIRECTLY INVOLVED IN AN OPERROR THAT OCCURRED AT XA41 AM MDT. THE INCIDENT IN QUESTION OCCURRED IMMEDIATELY AFTER I ASSUMED CTL OF THE LCL/GND POS. C130 HAD JUST BEEN CLRED FOR TKOF ON RWY 35 BY THE PREVIOUS CTLR AND PRIOR TO THE POS RELIEF BRIEFING. AFTER THE BRIEFING, I ASSUMED CTL OF THE LCL/GND POS. A GND VEHICLE REQUESTED CLRNC TO CROSS RWY 35 AT MID FIELD. UNDER THE ASSUMPTION THE C130 WAS NOT YET CLRED FOR TKOF, I CLRED THE VEHICLE TO CROSS RWY 35. THE C130 THEN ADVISED OF THE ABORTED TKOF DUE TO A VEHICLE ON THE RWY. THE POS RELIEF BRIEFING THAT I RECEIVED WAS COMPLETE AND CONCISE. TFC WAS LIGHT, WITH ONLY 3 ACFT ON FREQ AND A GND VEHICLE. THE C130 BROUGHT THE INCIDENT TO MY ATTN BY ADVISING HIS ABORTED TKOF. MY PERCEPTION OF THE TFC PICTURE WAS THAT THE C130 DID NOT HAVE A TKOF CLRNC. A HEARBACK PROB DURING THE POS RELIEF BRIEFING PLAYED A CONTRIBUTING FACTOR IN THE INCIDENT. THE PERCEPTION OF WHAT I HEARD DURING THE BRIEFING, WAS IN ACTUALITY, NOT WHAT WAS COMMUNICATED. IN ADDITION, A BREAKDOWN IN VISUAL SCANNING TECHNIQUES ALSO PLAYED A ROLE. HAD I SCANNED THE RWY VISUALLY PRIOR TO ISSUING THE XING CLRNC, IT WOULD HAVE ALERTED ME THAT AN ACFT WAS IN POS FOR TKOF. LACK OF AWARENESS, RATHER THAN POOR JUDGEMENT WERE PRIMARY FACTORS IN THE INCIDENT. ON THAT DAY, PRIOR TO RPTING FOR WORK, I CONSIDERED REQUESTING SICK LEAVE DUE TO A PHYSICAL ILLNESS. MY DECISION WAS TO RPT FOR WORK. COGNITIVE AWARENESS WAS SOMEWHAT REDUCED BY THIS CONDITION AND I OVERESTIMATED MY ABILITIES TO FUNCTION UNDER THESE CIRCUMSTANCES. IN FUTURE, ESTABLISHING GOOD READBACK/HEARBACK TECHNIQUES AND INCORPORATING CONSISTENT SCANNING TECHNIQUES, I BELIEVE WILL HELP ELIMINATE FUTURE INCIDENTS SUCH AS THESE. UTILIZING SICK LEAVE THAT IS PROVIDED SHOULD BE ENCOURAGED AND UTILIZED WHEN PHYSIOLOGICALLY ONE IS NOT FUNCTIONING 100 PERCENT.

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.