[fingpilot]

This is actually a very interesting story with some real irony as well.

North-east bound private jet correctly level at 37000'. On a computer-generated flight plan from a commercial vendor (the way all of us private guys do it, especially internationally).

South-east bound 737 Flag carrier (Brazillian), also correctly level at 37000', on an airway that intersects and then joins the same airway that the northbound private jet is using.

Both planes in Radar contact (supposedy). There are known 'holes' in the coverage (in the area where the mid-air occured).

Both planes talking to ATC (supposedly). There are known radio gaps along this route (also in the area of the mid-air).

TCAS (the totally onboard system that warns of other aircraft in your vicinity, and displays thier relative location and reported altitude on a cockpit display) was functional on both airplanes. Both airplanes were NEW; the private jet had ferry time only (was on it's delivery flight), the Boeing had less than 400 hours on it.

ATC in Brazil was saying that the transponder was not functioning on the private jet. That was later amended to say that they had lost radar contact (looks the same as failed transponder, no primary returns in that area anyway) with the private jet (known to happen in that area, but not readily admitted to by anyone officially). It so happens that they lost radar contact with the southbound Boeing in the same area, but at the time they said it was because it was already hit by the private jet. Not that they had collided, but that it had been hit by the private jet. The bias in the initial Brazillian reporting was blatant. Brazillian airliner hit by American private jet sells newspapers and deflects criticism of third world infrastructure.

Here is where fate steps in.

TCAS has a nasty habit of 'dropping' tough to resolve contacts. What is the toughest? Head-on, same altitude. Closure speed is 900 knots. 12 miles a minute. Normal range of the TCAS is 25 to 40 miles (2 to 3 minutes total time). Less in certain regimes. The antennas for this system are mounted on top and bottom of the fuselages. Looking for 5-watt signals from other transponders out to 40 miles, with a closure rate of 900 knots. Worst case for the antennas? Side lobe (edge) of the antenna (on the horizon, or same altitude). Hmmm....

Now the sad part. The computer-generated flight plan for the private jet included an altitude change at the VOR beacon where these two airways joined. The private jet's airway changed course at this point, and the change normally would include an altitude level change because the course was now West of North, instead of East of North previously. The pilots were trying to contact ATC to inquire about this, and were not able to raise ATC (known area of poor radio comms).

The rules say no altitude change unless directed by ATC (even with a filed change in the flight plan). There are procedures for lost comms, but no one thought that was the case yet.

Sadly, the private jet pilots were caught in a quandry. They survived the mid-air. ATC was not about to take the blame for what they felt was an error on the part of the private jet guys. They said they never saw the Boeing, or had any warning on the TCAS. No warning was broadcast from the Boeing, and no one survived the crash.

Thankfully, the light of day and International Laws and procedures have come to prevail, and the cause and blame are being put where they belong. The antiquated ATC systems in that part of the world are the problem, now it will be interesting to see if they, and the procedures there will be fixed.

I doubt it.

I fly there enough to know how to handle the hours of lost comms in the interior of South America and Africa. It's sad that the International pilots of the world have had to develop procedures to cope with the antique infrastructure of a lot of this otherwise modern world.