Nct controller providing OJT experienced operational error when developmental controller failed to c...

Narrative:

Providing OJT to sfo arrival sector woodside trainee. Trainee issued traffic to air carrier Y of air carrier X for runway 28L. Air carrier Y was on approach to runway 28R. Air carrier Y reported traffic in sight. Trainee advised air carrier Y to 'maintain visual separation'. We both believed we heard an acknowledgment. Later inside the final approach fix air carrier X initiated a go around. The operations manager on duty investigated the go around. While listening to the tape the acknowledgment from air carrier Y to maintain visual separation sounded garbled on the tape so an operational error was identified since the tape could not confirmed the visual separation acknowledgment from air carrier Y. Later on we also got air carrier X to maintain visual separation from air carrier Y as he fell in trail 2.56nm. Contributing factors were busy traffic with aircraft transmissions blocking each other out due to volume.

Original NASA ASRS Text

Title: NCT controller providing OJT experienced operational error when developmental controller failed to confirm the visual separation instruction/s with one of the aircraft involved.

Narrative: Providing OJT to SFO Arrival Sector Woodside trainee. Trainee issued traffic to Air Carrier Y of Air Carrier X for Runway 28L. Air Carrier Y was on approach to Runway 28R. Air Carrier Y reported traffic in sight. Trainee advised Air Carrier Y to 'Maintain visual Separation'. We both believed we heard an acknowledgment. Later inside the final approach fix Air Carrier X initiated a go around. The Operations Manager on duty investigated the go around. While listening to the tape the acknowledgment from Air Carrier Y to maintain visual separation sounded garbled on the tape so an Operational Error was identified since the tape could not confirmed the visual separation acknowledgment from Air Carrier Y. Later on we also got Air Carrier X to maintain visual separation from Air Carrier Y as he fell in trail 2.56nm. Contributing factors were busy traffic with aircraft transmissions blocking each other out due to volume.

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	867636
Time
Date	201001
Local Time Of Day	0001-0600
Place
Locale Reference	NCT.TRACON
State Reference	CA
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Approach Instructor
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

Nct controller providing OJT experienced operational error when developmental controller failed to confirm the visual separation instruction/s with one of the aircraft involved.