Las local controller described a confused aircraft identity event when several aircraft awaiting dep...

Narrative:

Air carrier XXX1 was #1 for departure; I thought. I cleared him for take off; and he replied that he was number 5 in line. The #1 aircraft was actually air carrier XXX2. I had gotten the call sign wrong on initial taxi out; and the pilot of air carrier XXX2 did not correct me. I canceled take off clearance for air carrier XXX1; and issued it to air carrier XXX2. I then asked air carrier XXX1 his position; and he said 'spot 4'. I looked at spot 4; and saw a air carrier X aircraft that was near the gate; still quite a ways from spot 4; and a B767 parked in the holding pad. I had air carrier YYY1 on taxiway C; approaching right to left but he was no factor for the aircraft I saw. I told air carrier XXX2 to taxi via C to 25R; and went on to the next item. A few seconds later; a air carrier X aircraft asked who this guy was off his right; and that he was close. I looked back at spot 4; and saw both aircraft that I had seen before; neither having moved. I also saw a 3rd aircraft; that had apparently been on the other side of the B767; out of my sight. He was much closer to the exit point than the aircraft I had seen. Had I seen him when I issued the clearance; I would have told the air carrier X aircraft to give way to the air carrier Y aircraft. The air carrier X aircraft did give way; but the aircraft should not have been that close. Recommendation; there are 2 lights on the holding pad in front of the D concourse; and lights on the western portion of the ramp by this concourse. The ramp on the other side of the holding pad is unlit. With the heavy parked in the pad; I was unable to see the ramp on the other side of the parked plane. Lighting this area would be of help. Even with no planes parked there; at night it is sometimes impossible to tell what aircraft is the one calling; unless they are in close proximity to the holding pad and its lights; or they have their own lights on. I did not see any lights on the air carrier X aircraft outbound; so am assuming it had none on when he called for taxi.

Original NASA ASRS Text

Title: LAS Local Controller described a confused aircraft identity event when several aircraft awaiting departure were confused by the controller; an incorrect take off clearance issued and a related ground conflict developed.

Narrative: Air Carrier XXX1 was #1 for departure; I thought. I cleared him for take off; and he replied that he was number 5 in line. The #1 aircraft was actually Air Carrier XXX2. I had gotten the call sign wrong on initial taxi out; and the pilot of Air Carrier XXX2 did not correct me. I canceled take off clearance for Air Carrier XXX1; and issued it to Air Carrier XXX2. I then asked Air Carrier XXX1 his position; and he said 'Spot 4'. I looked at Spot 4; and saw a Air Carrier X aircraft that was near the gate; still quite a ways from Spot 4; and a B767 parked in the holding pad. I had Air Carrier YYY1 on Taxiway C; approaching right to left but he was no factor for the aircraft I saw. I told Air Carrier XXX2 to taxi via C to 25R; and went on to the next item. A few seconds later; a Air Carrier X aircraft asked who this guy was off his right; and that he was close. I looked back at Spot 4; and saw both aircraft that I had seen before; neither having moved. I also saw a 3rd aircraft; that had apparently been on the other side of the B767; out of my sight. He was much closer to the exit point than the aircraft I had seen. Had I seen him when I issued the clearance; I would have told the Air Carrier X aircraft to give way to the Air Carrier Y aircraft. The Air Carrier X aircraft did give way; but the aircraft should not have been that close. Recommendation; there are 2 lights on the holding pad in front of the D concourse; and lights on the western portion of the ramp by this concourse. The ramp on the other side of the holding pad is unlit. With the heavy parked in the pad; I was unable to see the ramp on the other side of the parked plane. Lighting this area would be of help. Even with no planes parked there; at night it is sometimes impossible to tell what aircraft is the one calling; unless they are in close proximity to the holding pad and its lights; or they have their own lights on. I did not see any lights on the Air Carrier X aircraft outbound; so am assuming it had none on when he called for taxi.

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	871542
Time
Date	201002
Local Time Of Day	0601-1200
Place
Locale Reference	LAS.Tower
State Reference	NV
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Route In Use	None
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Route In Use	None
Flight Plan	IFR
Person 1
Function	Flight Data / Clearance Delivery Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Ground Conflict Less Severe Deviation - Procedural Published Material / Policy

Las local controller described a confused aircraft identity event when several aircraft awaiting departure were confused by the controller; an incorrect take off clearance issued and a related ground conflict developed.