Pdx tower controller reported a large aircraft's wing went over a smaller aircraft; claimed by the s...

Narrative:

Aircraft X exited runway 28L and taxied via twy T to gate xy. At about the same time aircraft Y started taxiing out of the alley to runway 28L via B3. Aircraft X was well ahead of aircraft Y and normally would not be a factor; so I turned my attention elsewhere. Problem is that aircraft X was delayed on the taxiway waiting for a marshaller; and aircraft Y passed by him near the area where taxiways B and T converge before aircraft X moved clear of the taxiway. The aircraft X pilot claimed that aircraft Y's wing passed over his wing.I didn't notice it until they were almost next to each other. Traffic had just slowed down after being a little busy and I let my guard down. I need to keep up my scan when traffic slows. When I did notice it; I could have told aircraft Y to stop; but it looked like they had enough room to pass. It didn't seem worth the risk to have him slam on his brakes and possibly injure a flight attendant. I issued a caution to aircraft Y; wasn't much else I could do at that point.I was a little surprised aircraft Y didn't stop on his own and wait until there was more room. However; a pilot behind him had an excellent view and later told aircraft Y there was plenty of room. It wouldn't hurt if aircraft X had given me a heads up when he realized he would be delayed on the taxiway waiting for a marshaller. I later spoke to the aircraft X pilot on the phone. He was cool about it.

Original NASA ASRS Text

Title: PDX Tower Controller reported a large aircraft's wing went over a smaller aircraft; claimed by the smaller aircraft. Smaller aircraft was delayed going into the alley way and larger aircraft continued taxiing. Another aircraft said there was plenty of room.

Narrative: Aircraft X exited Runway 28L and taxied via TWY T to gate XY. At about the same time Aircraft Y started taxiing out of the alley to Runway 28L via B3. Aircraft X was well ahead of Aircraft Y and normally would not be a factor; so I turned my attention elsewhere. Problem is that Aircraft X was delayed on the taxiway waiting for a marshaller; and Aircraft Y passed by him near the area where taxiways B and T converge before Aircraft X moved clear of the taxiway. The Aircraft X pilot claimed that Aircraft Y's wing passed over his wing.I didn't notice it until they were almost next to each other. Traffic had just slowed down after being a little busy and I let my guard down. I need to keep up my scan when traffic slows. When I did notice it; I could have told Aircraft Y to stop; but it looked like they had enough room to pass. It didn't seem worth the risk to have him slam on his brakes and possibly injure a flight attendant. I issued a caution to Aircraft Y; wasn't much else I could do at that point.I was a little surprised Aircraft Y didn't stop on his own and wait until there was more room. However; a pilot behind him had an excellent view and later told Aircraft Y there was plenty of room. It wouldn't hurt if Aircraft X had given me a heads up when he realized he would be delayed on the taxiway waiting for a marshaller. I later spoke to the Aircraft X pilot on the phone. He was cool about it.

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.

Attributes
ACN	1289273
Time
Date	201508
Local Time Of Day	1801-2400
Place
Locale Reference	PDX.Tower
State Reference	OR
Environment
Light	Daylight
Aircraft 1
Make Model Name	Light Transport High Wing 2 Turboprop Eng
Flight Phase	Taxi
Route In Use	Visual Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Widebody Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Ground
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 10
Events
Anomaly	Conflict Ground Conflict Less Severe Ground Event / Encounter Other / Unknown

Pdx tower controller reported a large aircraft's wing went over a smaller aircraft; claimed by the smaller aircraft. Smaller aircraft was delayed going into the alley way and larger aircraft continued taxiing. Another aircraft said there was plenty of room.