Townsend includes a FlightAware chart of the course of that flight. Records from that date (April 25) are now behind FlightAware's pay wall, but here is the version Townsend published:
The blue line, which is airspeed, shows a sudden reduction at the point he is describing, with the vertical red line. This could be consistent with either a sudden reduction in power or (unlikely in the circumstances) a climb. The mustard-colored line, for altitude, seems more or less steady. Flight Aware is highly fallible, but at face value this indicates the plane rock-steady at a certain altitude. (Townsend wrote to say the chart actually records the 600-foot drop. OK)
3) How close were the planes, anyway? The premise of this story was a hair's-breadth escape from death. Eg "Two jetliners six miles over the Pacific don’t come within scraping distance of each other without something going amiss." And "the FAA is in the dark on a near miss that could have taken more lives than any air accident in history."
To put this in perspective, the closest the planes appeared to have come to each other is at least 5 miles, and perhaps 8 miles (which is what CNN told Townsend when he appeared). If airplanes are headed directly head-to-head, distances can close fast. If each was going at top speed of 600 mph, or 10 miles per minute, then a head-to-head closing speed would be 20 miles per minute, or only 15 to 20 seconds of direct head-on flight. Still, the point is that the traffic systems in both planes warned both crews when detecting a danger, and sent them in diverging directions. A five-mile margin between planes is not "scraping distance."
(The simpler traffic-warning system I have in my propeller plane sends alerts when planes are within 6 miles' distance. That is far enough away that usually it is very hard even to see the plane causing the alert.)
4) How close to the brink is the whole system? The post mentions the amazing safety record of commercial aviation, and also the irrational nature of fears involving flight:
Regardless, plane crashes hold a unique place in our fears: the fiery violence, the lack of control — they have a scale and spectacle that makes them loom larger than their actual threat. Similarly, more Americans are killed by vending machines than sharks every year, but more people fear sharks than vending machines.
All that is true. But I don't agree, as the piece goes on to claim, that "the [safety] system appears broken" or that airlines are left to "self-police" for safety regulations. Anyone who has dealt with the FAA can report otherwise. And to judge by the record, when was the last time two airliners collided in the United States? Hint: it was 49 years ago, and four people of the 122 aboard died. When was the last airliner-collision large-scale catastrophe in the US? It was when Dwight Eisenhower was president, and everything about technology was different.
Again, I think I'd agree with this author on most things, and I am meaning to be respectful about the article he wrote and the scare he endured. But people who think: first MH370, now this??? should think again. Several million commercial airline flights have taken off and landed safely worldwide since that Malaysian flight disappeared. Including the one Kevin Townsend describes.
Life is full of danger, including aboard aircraft. But if other aspects of life had even half the safety-consciousness of today's commercial air travel system, we'd live in a remarkably less perilous society.