Sjc tower controller reported being distracted by an incorrect beacon code. The reporter failed to n...

Attributes
ACN	1459012
Time
Date	201706
Local Time Of Day	1801-2400
Place
Locale Reference	SJC.Tower
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	SR22
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Route In Use	None
Flight Plan	VFR
Aircraft 2
Make Model Name	Citationjet (C525/C526) - CJ I / II / III / IV
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 2
Events
Anomaly	ATC Issue All Types Conflict Ground Conflict Critical

Narrative:

Four departures were waiting and one arrival. I departed a PC12 IFR from runway 30R; departed a bonanza from runway 30L; then crossed a king air waiting for IFR release to hold between the runways to get a cirrus VFR departure airborne. I told the citation on final one VFR departure prior to their arrival and cleared [the citation] to land. I cleared [the cirrus] for departure 'no delay' traffic on 1.5 mile final. [The cirrus] responded with we have the traffic in sight and cleared for takeoff. I advised [the cirrus] to expect an offset as soon as airborne. When I turned to radar identify [the bonanza] on the upwind it had a wrong squawk code. As I verified the squawk code [the citation] said there's an aircraft on the runway. I gave instructions to start a climb go around or change to runway 30R. The cirrus took his time for departure roll.I should be more cautious with unfamiliar call signs and the moment the aircraft sounded unsure with the read back it was best to cancel take off clearance.

Original NASA ASRS Text

Title: SJC Tower Controller reported being distracted by an incorrect beacon code. The reporter failed to notice an aircraft on the runway with landing traffic on short final.

Narrative: Four departures were waiting and one arrival. I departed a PC12 IFR from Runway 30R; departed a Bonanza from Runway 30L; then crossed a King Air waiting for IFR release to hold between the runways to get a Cirrus VFR departure airborne. I told the Citation on final one VFR departure prior to their arrival and cleared [the citation] to land. I cleared [the Cirrus] for departure 'no delay' traffic on 1.5 mile final. [The Cirrus] responded with we have the traffic in sight and cleared for takeoff. I advised [the Cirrus] to expect an offset as soon as airborne. When I turned to radar identify [the bonanza] on the upwind it had a wrong squawk code. As I verified the squawk code [the citation] said there's an aircraft on the runway. I gave instructions to start a climb go around or change to Runway 30R. The Cirrus took his time for departure roll.I should be more cautious with unfamiliar call signs and the moment the aircraft sounded unsure with the read back it was best to cancel take off clearance.

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.

Sjc tower controller reported being distracted by an incorrect beacon code. The reporter failed to notice an aircraft on the runway with landing traffic on short final.