Spotting Traffic

TCAS II is the most comprehensive form of TCAS, but its range depends on what it is asked to do. Overall pulse detection range is 30 NM for Mode S transponders and 14 NM for Mode A/C units. Surveillance must be reliable within 14 NM, but TCAS II will only assess threats within 12 NM as possible RAs. TCAS II guarantees system reliability within at least 4.5 NM. Two TCAS II systems can coordinate RAs to maximize vertical separation, typically 300-700 feet. There is even a reverse RA if one aircraft fails to respond correctly in the latest version 7.1 software.

Fred Simonds

Wednesday, September 25, 2019 at 12:00 AM ET

Verified

The Dream Chaser spacecraft is one step closer to its goal of orbital flight after the completion of a successful first captive carry test. Sierra Nevada Corporation

Key Takeaways:

Systematic visual scanning, or "see and avoid," is the fundamental and primary method for preventing mid-air collisions, requiring specific techniques to overcome human eye limitations.
Electronic systems like ADS-B, TCAS I/II, and Traffic Advisory Systems (TAS) supplement visual scanning by providing varying levels of traffic awareness.
While ADS-B and TCAS I/TAS offer traffic advisories, only TCAS II (mandated for larger aircraft) provides Resolution Advisories (RA) to command vertical avoidance maneuvers as a last-resort defense, though all electronic aids have operational and cost limitations.

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As a post-solo student, I lined up nicely on final. I had it nailed. Suddenly I felt my instructor’s hands on the yoke. I was annoyed because I didn’t need help. He pointed up to the right. Oh. There’s another plane on final, maybe a hundred feet above us. Fixated on the landing, I’d not learned how to scan. My instructor broke off the approach and advised the tower.

I was shaking. John tried to soothe me with the “big sky” theory. Making my worst mistake in aviation, I quit.