Narrative:

Position and hold on runway 28R in sfo; heavy air carrier also in position on runway 28L; additional aircraft inbound to our runway (28R). Runway 28L traffic cleared for takeoff; we started our timer for 2 minutes and looked at the TCAS for the 5 miles for wake turbulence avoidance. At approximately 1 min 17 seconds and 3.5 miles we were cleared for takeoff; I asked how far the heavy was and noted that we didn't have two minutes. ATC replied that he didn't know that we needed two minutes. I replied that it is either two minutes or 5 miles and that we had neither; ATC replied that we would have had way more than 5 miles. Due to this discussion with ATC; the aircraft that was inbound to our runway was issued a go-around clearance and then instructed us to clear the runway. After approximately 10 minutes we were again cleared for takeoff; as sfo tower handed us off to departure he told me that we were to call tower via telephone. We called sfo tower; they told us that if we want to wait for two minutes instead the five miles we have to inform them of this prior to taking the runway. We did; however; not know which aircraft would takeoff first. When we mentioned that we didn't have the 5nm either he told us that based on their info we would have had at least 5nm by the time we got airborne. This; however; is not what we saw. In our mind we did not have two minutes or five miles and chose the most conservative path of not taking off. Next time we should clarify as early as possible that we want to wait 2 minutes as opposed to the five miles.

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Original NASA ASRS Text

Title: Corporate jet cleared for takeoff on Runway 28R following heavy departure off Runway 28L requested 2 minute delay resulting in go around event; ATC noting required 5 miles separation had been insured.

Narrative: Position and hold on Runway 28R in SFO; Heavy air carrier also in position on Runway 28L; additional aircraft inbound to our Runway (28R). Runway 28L traffic cleared for takeoff; we started our timer for 2 minutes and looked at the TCAS for the 5 miles for wake turbulence avoidance. At approximately 1 min 17 seconds and 3.5 miles we were cleared for takeoff; I asked how far the heavy was and noted that we didn't have two minutes. ATC replied that he didn't know that we needed two minutes. I replied that it is either two minutes or 5 miles and that we had neither; ATC replied that we would have had way more than 5 miles. Due to this discussion with ATC; the aircraft that was inbound to our runway was issued a go-around clearance and then instructed us to clear the runway. After approximately 10 minutes we were again cleared for takeoff; as SFO Tower handed us off to Departure he told me that we were to call Tower via telephone. We called SFO Tower; they told us that if we want to wait for two minutes instead the five miles we have to inform them of this prior to taking the runway. We did; however; not know which aircraft would takeoff first. When we mentioned that we didn't have the 5nm either he told us that based on their info we would have had at least 5nm by the time we got airborne. This; however; is not what we saw. In our mind we did not have two minutes or five miles and chose the most conservative path of not taking off. Next time we should clarify as early as possible that we want to wait 2 minutes as opposed to the five miles.

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.