Medium large transport made go around after tower had changed runway assignment twice.

Attributes
ACN	81075
Time
Date	198801
Day	Mon
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : sfo
State Reference	CA
Altitude	agl bound lower : 0 agl bound upper : 100
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : sfo
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent : approach landing : go around
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Flight Phase	ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 15000 flight time type : 5000
ASRS Report	81075
Person 2
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation

Narrative:

We were on a visual approach behind a widebody transport for runway 28R. At about 1000' AGL the tower offered us 28L. We changed to 28L and the tower clrd the widebody transport to cross 28L ahead of us. The widebody transport delayed crossing and when we were close in the tower offered us 28R. We attempted to change to 28R but were too close in to maneuver and so we went around.

Original NASA ASRS Text

Title: MLG MADE GO AROUND AFTER TWR HAD CHANGED RWY ASSIGNMENT TWICE.

Narrative: WE WERE ON A VISUAL APCH BEHIND A WDB FOR RWY 28R. AT ABOUT 1000' AGL THE TWR OFFERED US 28L. WE CHANGED TO 28L AND THE TWR CLRD THE WDB TO CROSS 28L AHEAD OF US. THE WDB DELAYED XING AND WHEN WE WERE CLOSE IN THE TWR OFFERED US 28R. WE ATTEMPTED TO CHANGE TO 28R BUT WERE TOO CLOSE IN TO MANEUVER AND SO WE WENT AROUND.

Data retrieved from NASA's ASRS site as of August 2007 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.