DEVELOPMENTAL CTLR CLEARED SMA FOR TKOF WITH MEN AND EQUIPMENT ON THE RWY; INSTRUCTOR CTLR NOT MONITORING TRAINEE.

Narrative

I WAS GIVING OTJ TRNING TO A DEVELOPMENTAL ON THE LCL CTL POS. WHEN WE ASSUMED THE POS WE WERE TOLD IN THE BRIEFING AND ACKNOWLEDGED THAT A SURVEY CREW AND VEH WERE OPERATING ON RWY 21. TFC WAS LIGHT; IN THE 10 MIN TIME PERIOD PRIOR TO THE INCIDENT THERE WAS ONE ARR ON RWY 15. I STARTED TO LOOK SOMETHING UP IN THE ATC HANDBOOK TO ANSWER A QUESTION THAT HAD COME UP EARLIER. WHILE I WAS DOING THIS I HEARD THE DEVELOPMENTAL ISSUE AN IFR CLRNC AND TAXI INSTRUCTIONS TO AN SMA. BECAUSE I WAS READING SOMETHING; I DIDN'T REALIZE THE SMA WAS GOING TO RWY 21; NOR WAS I WATCHING THE SITUATION DEVELOP. A FEW MINUTES LATER; THE DEVELOPMENTAL ISSUED A TKOF CLRNC TO THE SMA. I WAS ALERTED TO THE SITUATION WHEN THE SMA QUESTIONED WHY THERE WAS A TRUCK ON THE RWY. THE SMA PASSED APPROX 200' ABOVE THE SURVEY CREW WHO WERE 5000' FROM THE APCH END. I WAS LULLED INTO A SENSE OF COMPLACENCY BECAUSE THE DEVELOPMENTAL HAD 5 MONTHS EXPERIENCE ON LCL CTL AND TFC WAS LIGHT--NO EXCUSE AS I AM RESPONSIBLE FOR THE POS. SINCE THIS INCIDENT; THE TWR MGR AND ARPT MGR HAVE AGREED TO CLOSE A RWY WHEN MEN OR EQUIPMENT WILL BE WORKING ON OR ALONG SIDE THE RWY.