A319 first officer reported executing a go-around due to a conflict with an aircraft of the runway.

Narrative:

Approach told us to expect the visual approach to runway 06L. The first officer (pilot flying) loaded the ILS 06L in the FMS and we confirmed the approach. We got vectors to a visual approach for 06L and used the ILS 06L as a backup. Approach told us to contact the tower at the FAF; but I was late switching over to tower due to completing the landing checklist. When I checked in with tower; I said that we were on final for runway 06L (I don't remember getting a response). When we were on short final; a B777 taxied onto runway 06L and it was clear that we had a traffic conflict with the B777. When the tower contacted us; I stated that we were on final for runway 06R. Tower then cleared us to land on runway 06R; but there was no way to make it over to that runway from such a low altitude; so I called 'go-around.' the event occurred because of a traffic conflict with the departing B777 on runway 06L. I don't think it is a good procedure for approach control to tell pilots to contact the tower at a specific geographical point. How do they know that we won't have a higher-priority task at that point in the future? The truth is that they don't. In this instance; there was time available for me to call the tower prior to the FAF; but at the FAF; I was busy with a higher-priority task (aviate; navigate; communicate). If I had been given an instruction to switch to tower immediately; I would have worked it into my work flow at the appropriate time.

Original NASA ASRS Text

Title: A319 First Officer reported executing a go-around due to a conflict with an aircraft of the runway.

Narrative: Approach told us to expect the visual approach to Runway 06L. The First Officer (Pilot Flying) loaded the ILS 06L in the FMS and we confirmed the approach. We got vectors to a visual approach for 06L and used the ILS 06L as a backup. Approach told us to contact the Tower at the FAF; but I was late switching over to Tower due to completing the Landing Checklist. When I checked in with Tower; I said that we were on final for Runway 06L (I don't remember getting a response). When we were on short final; a B777 taxied onto Runway 06L and it was clear that we had a traffic conflict with the B777. When the Tower contacted us; I stated that we were on final for Runway 06R. Tower then cleared us to land on Runway 06R; but there was no way to make it over to that runway from such a low altitude; so I called 'go-around.' The event occurred because of a traffic conflict with the departing B777 on Runway 06L. I don't think it is a good procedure for Approach Control to tell pilots to contact the Tower at a specific geographical point. How do they know that we won't have a higher-priority task at that point in the future? The truth is that they don't. In this instance; there was time available for me to call the Tower prior to the FAF; but at the FAF; I was busy with a higher-priority task (aviate; navigate; communicate). If I had been given an instruction to switch to Tower immediately; I would have worked it into my work flow at the appropriate time.

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	1651460
Time
Date	201904
Local Time Of Day	1201-1800
Place
Locale Reference	CYYZ.Airport
State Reference	ON
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Experience	Flight Crew Total 9000
Events
Anomaly	ATC Issue All Types Conflict Ground Conflict Critical Ground Incursion Runway