Spatial Separation - CLOSE CALL? Impending MIDAIR COLLISION?

[USAFSS-ColdWarrior]

OK... So I already know there was NO COLLISION. And that "close" only counts in horseshoes, hand grenades, and atomic weapons, but.....

This morning, on my way to work, I witnessed two converging contrails in the eastern sky from my vantage point within the city of San Angelo, TX.

The "vertical" track is headed due west from the rising sun and is most probably regularly scheduled civilian traffic out of San Antonio. The "horizontal" track from left to right is typical military traffic bound for Del Rio, Texas.

I have no idea what the vertical separation of these two aircraft may have been, but from my perspective, I'm envious of the cockpit view that one crew had!

 

[pmramsey]

At the altitude that you picture, the aircraft are both flying at "pressure altitudes" meaning they set their altimeters to 29.96 as they climb through 18,000 feet. Altitude separation should be a minimum of 4,000 feet above 29,000. Given the different direction of travel based on magnetic compass headings, the altitude separation would be 6,000 feet. However, visibility appears to be "severe clear," therefore, with the advice and consent of ATC for this upper-level airspace, one or both of the aircraft may close the required separation provided the one aircraft maintains constant visual contact with the other aircraft.

 

[marchplumber]

At the altitude that you picture, the aircraft are both flying at "pressure altitudes" meaning they set their altimeters to 29.96 as they climb through 18,000 feet. Altitude separation should be a minimum of 4,000 feet above 29,000. Given the different direction of travel based on magnetic compass headings, the altitude separation would be 6,000 feet. However, visibility appears to be "severe clear," therefore, with the advice and consent of ATC for this upper-level airspace, one or both of the aircraft may close the required separation provided the one aircraft maintains constant visual contact with the other aircraft.

Uhmmmm,,,,,,,,,,,,,,,,,,,,yeah,,,,,,,,,,,,,,,,,,,,,what he said. Of course...... absolutely. (LOL)
God bless,
Tony

 

[foxmike]

Aircraft above 18,000' or FL180 actually set altimeters to 29.92 and minimum altitude separation is 1000' vertically. It is really neat to pass another aircraft at over 1000 kts closure just 1000 feet away!

So while those 2 planes look like they were going to hit each other, they were under ATC radar control the entire time. Many times you will see converging contrails and navigation waypoint intersections or air routes. Think of highways in the sky. Every once in a while, they have to cross, just like an interstate. Some of my favorite views are when you get towards the west coast. Lots of contrails converging on Los Angeles.