NMAC near SFO

[kkoran]

Once you say you have the other aircraft in sight and can maintain visual separation that's what you're supposed to do. I wonder if the smaller airplane, whatever it was, had some other airplane in sight and didn't see the 777, either that or maybe he didn't judge his closure rate properly.

No. Not much the guy to do in the 12 seconds between the tower telling him to maintain visual separation and the tower telling the 777 that traffic was no longer a factor.

 

[rottydaddy]

You do realize that 1500ft of horizontal distance would be achieved in under 6 seconds (assuming a climbout at 165kts) by the B777!

I'm still thinking that should sell papers!

I'm not so sure, myself... if it really was 1500 feet laterally, that's not acceptable in that scenario, but not as alarming as 300 feet in a straight line from airplane to airplane. If you can see the other traffic, and their movement is predictable, six seconds to do something about it is not too bad. Regardless of what type you are flying, you can increase that time by immediately slowing down or maneuvering. And the heavy was moving along two axes, so despite the climb it should have been moving away relative to the single.

Assuming that there was still 1500 feet laterally, even when it officially became a "deal", I can see now how the pilot of the single could have "let it go that far."

But 1500 feet is still pretty damn close... uncomfortably close.
Whenever you have visual contact, the time to act is when you see the mere possibility of conflict (especially when you have also been alerted by ATC), and the measures taken should be conservative.

Maneuvering near some of the lower approaches to KEWR, just outside the outer tier of the Class B, I've come within a little less than a mile of descending airliners. Despite scanning properly, they can occasionally get that close, if they are approaching from the blind spots aft of the wing. I turn immediately when I see them, even if I see that they are turning away (or just happen to be turning). And I certainly don't wait until some given distance- I turn when I see them, unless it's very clear that they are moving away from me, and can be expected to continue doing so.

You can't have too much separation with fast-moving traffic, and turning usually presents a bigger visual target, especially with a glider. It has no transponder, so if they have gotten within a mile, there's a good chance they just don't see me. That puts the responsibility on me. I may have to abandon a nice thermal, but I can live with that.

I may legally have the right-of-way in such a situation, and the existing separation may be within legal limits, but in VMC, the law isn't going to keep us safe up there, any more than the controllers. That's what "see and avoid" is all about.

 

[dmccormack]

You can't have too much separation with fast-moving traffic, and turning usually presents a bigger visual target, especially with a glider. It has no transponder, so if they have gotten within a mile, there's a good chance they just don't see me. That puts the responsibility on me. I may have to abandon a nice thermal, but I can live with that. .

Very, very true.

I've spotted previously invisible traffic in the pattern and elsewhere when the traffic turned, and when I get near an airport in the mostly-white Chief I always turn right and left -- to scan and to help being seen.

Our eyes are very good at picking up movement and change at a distance.