Narrative:

Aircraft X landed runway 28R and slowed enough to make [the] turn off on runway 32. My trainee instructed pilot to turn right on runway 32. We observed aircraft X begin to turn; but then return to centerline and continued down runway. Once trainee saw aircraft X begin a turn; he quickly cleared aircraft Y for takeoff before verifying aircraft X had actually exited the runway. Before I could key up to cancel the takeoff clearance; aircraft Y rejected the clearance saying he saw the other aircraft still on the runway. I told aircraft Y to cancel takeoff clearance and hold position. Aircraft X then missed the next turnoff and moved very slowly down the runway. Aircraft X asked us which exit he was supposed to make. As this was happening; [the] trainee decided the next arrival was too close to get aircraft Y airborne; [and] he instructed aircraft X to turn right and exit runway at C12. Aircraft X was instructed to exit at C5 and contact ground. Aircraft Y was not exiting the runway quickly enough; so trainee told aircraft Z to go-around. Trainers and trainees must do a better job of scanning runways and verifying arrivals have exited prior to issuing takeoff clearance to subsequent aircraft.

Related reports:

Google
 

Original NASA ASRS Text

Title: PBI Tower Controller/Instructor reported a runway incursion involving an arrival not exiting the runway quick enough; a departure cleared for takeoff; and an arrival having to be sent around.

Narrative: Aircraft X landed Runway 28R and slowed enough to make [the] turn off on Runway 32. My Trainee instructed pilot to turn right on Runway 32. We observed Aircraft X begin to turn; but then return to centerline and continued down runway. Once trainee saw Aircraft X begin a turn; he quickly cleared Aircraft Y for takeoff before verifying Aircraft X had actually exited the runway. Before I could key up to cancel the takeoff clearance; Aircraft Y rejected the clearance saying he saw the other aircraft still on the runway. I told Aircraft Y to cancel takeoff clearance and hold position. Aircraft X then missed the next turnoff and moved very slowly down the runway. Aircraft X asked us which exit he was supposed to make. As this was happening; [the] Trainee decided the next arrival was too close to get Aircraft Y airborne; [and] he instructed Aircraft X to turn right and exit runway at C12. Aircraft X was instructed to exit at C5 and contact Ground. Aircraft Y was not exiting the runway quickly enough; so Trainee told Aircraft Z to go-around. Trainers and trainees must do a better job of scanning runways and verifying arrivals have exited prior to issuing takeoff clearance to subsequent aircraft.

Data retrieved from NASA's ASRS site 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.