I had gone down to Sarasota this morning and was on my way back. Tampa had climbed me to 5,000' and I wsa on an assigned heading. I heard a Southwest flight get called traffic, 12'Oclock 12 miles and then I was given the traffic, opposite direction at 6,000'.
The controller told me to look for a 737, which is all that Southwest has. Looking at the traffic display I saw the target and selected it. The GTN650 xi allows you to select a target. It then gives you the identifier, aircraft type and closure rate. The closure this morning was 446 knots.
This made sense, you can ignore the wicjed headwind I had as it impacted both of us. My TAS was around 178 knots which meant he was moving 286 knots. The speed limit is 250 but since he was at 6,000', his TAS was likely around this, my numbers say he was a few knots fast but who's counting.
I had him on ADSB at 12 miles and by tapping the icon I saw that he would pass almost right over me. Technology is awesome. So at 464 knots closure, we were closing the gap at 7.7 miles a minute. This means the gap shrinks 1 mile every 7.76 seconds. The visibility was pretty good, more than 10 miles. Lots of clouds out but we were both in clear air. He had his lights on and I had mine on, including my landing light pulse lights.
This is what I saw at 21 seconds out or 3.2 miles. Yeah I had nothing. Typically I find that you pick up traffic about 2 miles out in these conditions. Let me zoom in, I did not see him but the phone did capture him, my guess is that with the head on profile it was too small a dot for my eyes to detect.
I saw him a few seconds before this picture which was likely right around 2 miles. This picture is at about 9 seconds before we passed.
My final snapshot was about half mile apart. I had already called the traffic but the Southwest crew never saw me. I am not surprised, with the lighting and looking down, they would have had a small window to pick me out. The emlargement is the first picture above. You can clearly see the Southwest colors but in the moment it was a black shape that came and went fast.
