The Brazilian midair.
As a new subscriber, I am very satisfied with the magazine. However, the article, "The Brazilian Midair" (January 2007), contains one statement I consider arguable. Brazilian ATC's pre-takeoff clearance to the Legacy is quoted as, "N600XL, Clear, 370, Manaus," followed by the statement that "Any pilot receiving this clearance--while still on the ground--would have been justified in believing their flight had been cleared to climb and maintain FL370 all the way to its destination." That's where I disagree.
Since the filed flight plan included three different altitudes, the clearance contains an immediate and obvious deviation or, more likely, it refers to the first phase of the flight only. In any case, as per FAR Part 91.123(a), "When a pilot is uncertain of an ATC clearance, that pilot shall immediately request clarification from ATC." The second phase of the flight along airway UZ6, according to the flight plan, implied a change in altitude for a reason, since UZ6 is a two-way airway where altitude separation is mandatory.
It is quite clear that the Legacy's altitude was not properly monitored by ATC and poor radio communication existed after the Legacy passed BRS. To make things worse, there is a disabled or malfunctioning transponder. Under those circumstances, I believe that the safest attitude would have been to follow the filed flight plan with the pre-established altitudes. The crew would be fully covered if they did so and the collision would have been avoided. Flight plans are normally correct.
Justin A. Zaragoza
You raise several good points, many of which highlight one of the central issues raised by this tragedy: the differences between rules and practices in the U.S. and other countries.
Regarding the initial clearance, no U.S. pilot would change cruising altitudes without a subsequent clearance. Brazilian ATC had ample opportunity to issue such a clearance. Too, the FAR you cite doesn't apply in Brazilian airspace.
Additionally, we and others have attempted to research related differences between U.S. and Brazilian regulations but--to our knowledge--no one has come up with any smoking gun. And, you're absolutely right that poor communications and surveillance existed for the Embraer. But how were they supposed to know to implement lost-communications procedures?
Finally, we'd quibble a bit with your statement that flight plans are "normally correct." We long ago lost count of the number of changes ATC has thrown at us, often before leaving the ground.