San controller described an asde-X alert when landing traffic directed to exit at taxiway B9 awaited...

Narrative:

I was working the ground control position. Aircraft X; B757 was exiting the runway and given instructions to taxi to the ramp via 'bravo.' (the taxiway). B757 was clear of the runway and slowed because there was an aircraft in the alley and the pilot desired to proceed in a straight line to his gate. The aircraft in the alley was holding short of 'bravo' as instructed. B757 then stopped and was instructed to taxi westbound on 'bravo' to the ramp. He replied that the other aircraft needed to move to allow him to his gate. The aircraft in the alley was then instructed to angle to his right and join 'bravo'; which he did. Aircraft Y a B737 was then able to taxi straight line to his gate. Meanwhile the local controller had issued a takeoff clearance to aircraft Z; another B737. The asde-X is not properly aligned and showed the aircraft Y target edge touching the runway edge at the bravo 9 intersection. Also the B757 target display on the asde-X is much larger than the actual aircraft size. The asde-X alerted as the aircraft Z (B737) was on departure roll. Aircraft Y was clear of the runway and was again slowly moving toward his gate at this time. If either the target size was realistic; or the map properly aligned; there would have been no alert. Recommendation; I recommend that the asde-X at san map be properly aligned. I also recommend the aircraft target size be adjusted to realistically represent the aircraft size.

Original NASA ASRS Text

Title: SAN Controller described an ASDE-X alert when landing traffic directed to exit at Taxiway B9 awaited traffic exiting from the gate area and activated the alert; the reporter noted the ASDE-X equipment was misaligned.

Narrative: I was working the Ground Control position. Aircraft X; B757 was exiting the runway and given instructions to taxi to the ramp via 'Bravo.' (the taxiway). B757 was clear of the runway and slowed because there was an aircraft in the alley and the pilot desired to proceed in a straight line to his gate. The aircraft in the alley was holding short of 'Bravo' as instructed. B757 then stopped and was instructed to taxi Westbound on 'Bravo' to the ramp. He replied that the other aircraft needed to move to allow him to his gate. The aircraft in the alley was then instructed to angle to his right and join 'Bravo'; which he did. Aircraft Y a B737 was then able to taxi straight line to his gate. Meanwhile the Local Controller had issued a takeoff clearance to Aircraft Z; another B737. The ASDE-X is not properly aligned and showed the Aircraft Y target edge touching the runway edge at the Bravo 9 Intersection. Also the B757 target display on the ASDE-X is much larger than the actual aircraft size. The ASDE-X alerted as the Aircraft Z (B737) was on departure roll. Aircraft Y was clear of the runway and was again slowly moving toward his gate at this time. If either the target size was realistic; or the map properly aligned; there would have been no alert. Recommendation; I recommend that the ASDE-X at SAN map be properly aligned. I also recommend the aircraft target size be adjusted to realistically represent the aircraft size.

Data retrieved from NASA's ASRS site as of April 2012 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	952745
Time
Date	201106
Local Time Of Day	1801-2400
Place
Locale Reference	SAN.Tower
State Reference	CA
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Aircraft 2
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Ground
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types

San controller described an asde-X alert when landing traffic directed to exit at taxiway B9 awaited traffic exiting from the gate area and activated the alert; the reporter noted the asde-X equipment was misaligned.