Date: 201306
Location: ZZZ.Airport, US
Aircraft: B777-300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower ZZZ
Second aircraft: B777 Undifferentiated or Other Model
Reporter organization: Government
Reporter function: Supervisor / CIC
Reporter qualification: Air Traffic Control Fully Certified
Second reporter function: Local
Anomaly: ATC Issue All Types; Conflict Airborne Conflict
Detector: Person Air Traffic Control
Result: Flight Crew Executed Go Around / Missed Approach
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I observed a B777 exit Runway XXL at and stop prior to clearing the runway. He called Ground Control and received no response due to the actions of the; just on position; instructor and developmental who were in the midst of both a position briefing (instructor to developmental) and unplugging and replugging into the headset jacks to the proper positions for instructor and developmental. I was monitoring their position as CIC/Coordinator and heard the B777 call and receive no response. I told them that the B777 was calling them. The B777 stopped movement when no response was received. The aircraft was still not clear of Runway XXL when this occurred. I was also watching a second B777; on short final for Runway XXL and determined there would be no time for the first B777 to clear the runway in time for the other B777 to land so I went directly to the Local Controller and pointed out the conflict and said to send the B777 around. Neither the point out; nor the verbal warning were acted upon. The B777 continued past the landing threshold and into the flair when the pilot of the B777 initiated a go-around on his own. At the time there was a GA transition aircraft (PA-28) approximately 1 mile north of the departure corridor for Runways XX heading southbound along the highway. As the second B777 was observed to go around; the Local Controller gave the B777 a heading of 280 and climb to 3 thousand feet. He then instructed the GA transition aircraft to make a right 360 degree turn. Traffic was exchanged between the missed approach aircraft and the GA aircraft. I then observed the B777 make a left turn in the vicinity of the maneuvering GA aircraft and then return to a westerly heading. Willingness of controllers to take under advisement the supporting input from others in the Tower environment and always having a plan ready when things don't work out. The heading given to the missed approach aircraft was ill advised.A divergent heading to the B777 of 265 degrees would have been more suitable due to the location of the transitioning aircraft.


Second narrative: I had a B777 on short final. I was working Local Control and a B777 I told to expedite to Delta without delay and to contact Ground. I observed the B777 clear of Runway XXL and I remember correctly the data tag had dropped off on my ASDE. I was watching to make sure the B777 was clear as [there was another B777] was on short final and I observed all wheels front and back clear. The RADAR Controller observed the B777 clear as well. There was training on Ground Control and there might have been a communication issue with the B777; but I can recall keeping a close eye. Looking out the Tower window and the B777 was clear of Runway XXL. [The B777 on short final] called Tower to say they were going around. I issued a 265 climbing to 3;100 because I had a transition Aircraft VFR at or below 2;000 approaching the departure corridor for Runway XX. I immediately went to the VFR aircraft and Issued a right 360. I did not want to turn the aircraft into the B777 and I also did not want the aircraft to continue the southbound course to put it directly into the B777's flight path. I issued the 265 heading to give me more separation. I called the traffic on the go-around (B777). The VFR pilot called visual and I remember telling the pilot to maintain visual. I just wanted them separated. I did ask the B777 what was the reason for the go-around and he/she stated traffic was on the runway. I did not believe traffic was on the runway at the time. I remember checking the ASDE and it showed traffic clear. There has been issues with the accuracy of the ASDE with data tags dropping off or just the accuracy in general; I remember we use to log it; but it happens so much I can honestly say we do not pay attention to it as much; because we are use to it. I believe one factor that led up to this event was having one runway to operate. Closing one of our major runways during one of the busiest days of the week; and possibly one of the busiest times of the day; can really add to complexity. The finals were pretty tight and it just added to the complexity even more. One recommendation I will have for myself is when in doubt send them around. In this case however; I did have a VFR transition and I do believe traffic was clear from what I observed with my own two eyes. The pilot initiated go-around did put it directly in conflict with the VFR transition. With the recent events with VFR transitions maybe we should take a look at possibly establishing different canned routes or altitudes. One recommendation I also have is having an ASDE that is accurate and works. An upgrade to ASDE would be great. I relied on what I believe I saw with my own two eyes and the eyes of my RADAR Controller. We have equipment that should have told my aircraft or vehicles are on the runway and for me to sent that aircraft around; that equipment seems to only work when we do a test every few days.


Synopsis: Tower Control reporters describe a go-around event and developing conflict when a B777 on flair elected to go-around because previous landing traffic was not clear of the runway.