Bwi controller described a asde-X alarm indicating an aircraft on runway 15L; the reporter noting a ...

Narrative:

Bwi was in an abnormal configuration departing runways 10 and 15L and arriving runways 10 and 15L. Training on local control; the trainee instructed the SR22 to luaw on runway 15L. The trainee then changed his/her mind and instructed the aircraft to taxi across the runway and hold short on the other side. There were no aircraft on final. The trainee wanted to depart aircraft from runway 10 and did not want to hold the aircraft in position for a long amount of time. After the aircraft taxied across the runway; the asde-X target did not fully clear the runway. Discussion occurred in the tower about the status of the aircraft and it was visually confirmed that the aircraft was holding short of the runway. The asde-X's target for the aircraft kept jumping. It would jump from clear of the runway to the icon being just on the runway. The C525 checked in on final for runway 15L and was cleared to land. On a 1/2 mile final; the asde-X alerted and said 'runway 15L occupied; go around;' the aircraft was not instructed to go around and again; the aircraft that was holding short was on the correct side of the hold short line. We submitted paperwork to the asde-X office of a false alert. [We] should have sent the aircraft around per the .65.

Original NASA ASRS Text

Title: BWI Controller described a ASDE-X Alarm indicating an aircraft on Runway 15L; the reporter noting a taxiing aircraft was observed by Tower personnel as clear of the runway so a landing clearance was issued contrary to procedures.

Narrative: BWI was in an abnormal configuration departing Runways 10 and 15L and arriving Runways 10 and 15L. Training on Local Control; the trainee instructed the SR22 to LUAW on Runway 15L. The trainee then changed his/her mind and instructed the aircraft to taxi across the runway and hold short on the other side. There were no aircraft on final. The trainee wanted to depart aircraft from Runway 10 and did not want to hold the aircraft in position for a long amount of time. After the aircraft taxied across the runway; the ASDE-X target did not fully clear the runway. Discussion occurred in the Tower about the status of the aircraft and it was visually confirmed that the aircraft was holding short of the runway. The ASDE-X's target for the aircraft kept jumping. It would jump from clear of the runway to the ICON being just on the runway. The C525 checked in on final for Runway 15L and was cleared to land. On a 1/2 mile final; the ASDE-X alerted and said 'Runway 15L occupied; go around;' the aircraft was not instructed to go around and again; the aircraft that was holding short was on the correct side of the hold short line. We submitted paperwork to the ASDE-X office of a false alert. [We] should have sent the aircraft around per the .65.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	999216
Time
Date	201203
Local Time Of Day	1201-1800
Place
Locale Reference	BWI.Airport
State Reference	MD
Aircraft 1
Make Model Name	SR22
Flight Phase	Taxi
Route In Use	None
Flight Plan	VFR
Aircraft 2
Make Model Name	Citationjet (C525/C526) - CJ I / II / III / IV
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types

Bwi controller described a asde-X alarm indicating an aircraft on runway 15L; the reporter noting a taxiing aircraft was observed by tower personnel as clear of the runway so a landing clearance was issued contrary to procedures.