B737 captain reported executing a go-around from the sfo ILS runway 28L after experiencing an near m...

Attributes
ACN	1368429
Time
Date	201606
Local Time Of Day	1801-2400
Place
Locale Reference	SFO.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	B737 Next Generation Undifferentiated
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 163
Events
Anomaly	Conflict NMAC Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy

Narrative:

We were cleared for the ILS 28L in san francisco. Passing 5000 feet on glideslope; ATC was vectoring a 777 to join us for a 'side by' for 28R. We were 18 miles out when we got a TA; and my first officer commented he was going to change the transponder from TA/RA to 'TA only' per our procedures in sfo and den. As the 777 approached the localizer; we noticed he would not be able to join his localizer but fly through ours as well. He was probably at 4000 feet.although we never received another TA; he was underneath us as we descended on the glideslope. I realized it wasn't going to work so I climbed from approximately 4500 feet to 5500 feet. Meanwhile; ATC was trying to send us around; but the call was blocked. I believe he flew directly under us less than 500 feet. We were vectored for another ILS with no further complications. Before we were handed off to tower; approach apologized and said that the 777 didn't turn in; in time. The next day I decided to review the transponder policy and realized we are supposed to switch to 'TA only' inside of eight miles. We were 18 miles out.I failed to brief the eight mile point for TA only. Without a brief of eight miles; I'm concerned most would switch from TA/RA to TA only further than eight miles when another aircraft pulls alongside.

Original NASA ASRS Text

Title: B737 Captain reported executing a go-around from the SFO ILS Runway 28L after experiencing an NMAC with a B777 on parallel approach to Runway 28R.

Narrative: We were cleared for the ILS 28L in San Francisco. Passing 5000 feet on glideslope; ATC was vectoring a 777 to join us for a 'side by' for 28R. We were 18 miles out when we got a TA; and my First Officer commented he was going to change the Transponder from TA/RA to 'TA only' per our procedures in SFO and DEN. As the 777 approached the localizer; we noticed he would not be able to join his localizer but fly through ours as well. He was probably at 4000 feet.Although we never received another TA; he was underneath us as we descended on the glideslope. I realized it wasn't going to work so I climbed from approximately 4500 feet to 5500 feet. Meanwhile; ATC was trying to send us around; but the call was blocked. I believe he flew directly under us less than 500 feet. We were vectored for another ILS with no further complications. Before we were handed off to Tower; Approach apologized and said that the 777 didn't turn in; in time. The next day I decided to review the Transponder policy and realized we are supposed to switch to 'TA only' inside of eight miles. We were 18 miles out.I failed to brief the eight mile point for TA only. Without a brief of eight miles; I'm concerned most would switch from TA/RA to TA only further than eight miles when another aircraft pulls alongside.

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.

B737 captain reported executing a go-around from the sfo ILS runway 28L after experiencing an near midair collision with a B777 on parallel approach to runway 28R.