Legacy/Gol Accident: Ignorance Is Bliss

Selling crazy on the internet is nothing new, but for some reason it’s really getting under my skin as it regards the Legacy/Gol accident. I got into it the other day on an internet forum with someone who was sure the bizjet crew had to be at fault, yet couldn’t explain why.

Can anyone out there explain to me why the Legacy crew was under house arrest for two months? Whatever the suspected cause of the accident, the detainment was a violation of the International Civil Aviation Organization’s (ICAO) 1963 Tokyo Convention, something to which every ICAO signatory subscribes.

As far as I can tell, the crux of the detainment stems from the fact that “the pilots did not stick to their flight plan”. To those who are not aviators, that probably sounds like an undeniable indicator of wrongdoing. But anyone who operates under or is knowledgeable about Instrument Flight Rules will tell you that a filed flight plan means nothing. In most places, pilots virtually never make a flight exactly as it appears on a flight plan. ATC is always giving re-routes, differerent altitudes, vectors, and doing other things to account for traffic conflicts, weather, and so on.

What matters is not what was filed, but what they were assigned in their clearance. And they were assigned the same altitude as the Gol 737. ATC instructed both planes to maintain same altitude and they complied with that clearance as required by regulations. Neither one knew that the other aircraft was at the same altitude. The only party with that information is air traffic control. They have the radar screens, the flight data strips, the “big picture”. They are the ones that issue routes to fly and altitudes to maintain, and therefore it seems to me that Brazilian ATC is the most likely culprit here.

Wherever you go on this planet, ATC’s primary job is to separate IFR traffic from other IFR traffic. Regulations require pilots to maintain a visual scan for other airplanes when flying in visual conditions, regardless of the flight rules under which they are operating. However, if one seeks to place blame on the Legacy crew for failure to see-and-avoid, then an equal share must fall on the Boeing’s flight crew.

Regulations aside, the see-and-avoid argument is a tough one to comply with in a place where airplanes can converge at up to 1,200 mph. That’s one mile every three seconds. This is one of the reasons airliners and business jets have Traffic Collision Avoidance Systems. TCAS systems not only alert the crew to traffic conflicts, but will actually communicate with TCAS systems in other aircraft and coordinate collision avoidance. This is known as a “resolution advisory”. One airplane’s TCAS will command the flight crew to climb, and the other aircraft’s crew will be ordered to descend.

As far as I know, there is no evidence whatsoever that the Legacy’s transponder was physically turned off by the pilots, or that the crew was doing anything improper or unusual. Mainstream media has reporting that the Legacy crew performed aerobatics, intentionally disabled their transponder, and refused to acknowledge ATC transmissions, but each of those claims later turned out to be unsubstantiated.

The one question mark is why the TCAS systems didn’t alert the flight crews to the impending conflict. The Legacy was brand new, having just rolled out of the factory shortly before the flight. Is it possible there was an avionics problem? An antenna issue? A blown circuit breaker or other fault? It’s possible. But whatever the cause, it seems likely that Brazil’s air traffic control system contributed mightily to this accident, something Brazil has been loathe to admit.

If you want to read an account of Brazilian air traffic control from someone who’s been there, here’s what a 38,000 hour pilot and former 747 captain had to say about flying in that neck of the woods:

I am not even slightly surprised that two aircraft collided while under “control” of Brazilian ATC, but I am very surprised we don’t see more such mid-airs. I flew in Central and South America, including Brazil, in the late ’50s, mostly cargo and ferry flights. In 1994, while working for JAL, I began flying three trips a month between Los Angeles and Sao Paulo until my “first retirement” in 2001. Not much had changed in the intervening four decades.

Communications are still horrible to non-existent. HF is still being used routinely, even when VHF is available. It is somewhat anachronistic to be flying near enough to Porto Velho to see the lights of the city, and still have to talk to them on HF. Call them on the VHF frequency and they may answer, but they will often ask to switch to HF for the position report, or for the next call. There is no question they prefer using HF, but I still don’t understand why. As far as I know, all ATC services are provided by the military, and by rather low-paid and poorly trained personnel. The results of that are inevitable, and many times I’ve flown through an ATC sector without being able to raise anyone, HF or VHF. If someone does respond, it is sometimes obvious they’ve just awakened. There are several sectors (Porto Velho being one) where any transmission from the ground is overwhelmed by loud music in the same room as the mike, and it sounds like the controller is across the room, yelling in the general direction of the mike. Party time, I guess, or maybe just trying to stay awake.

Even when the radio works, all communications are in Portuguese, unless no one on the aircraft can speak it. Then English will be used, but it’s very hard to understand. Of course, any transmission in English that is not absolutely standard and very common will not be understood on the ground at all, leading to “Say again?” or, worse, they will ignore further calls of any kind. The vast majority of flights over Brazil are flown by crews who do not speak either Portuguese or English as a native language, so it is the Tower of Babel all over again. It is dangerous, but heck, the same thing happens in France, Quebec, Russia and many other countries, too. We are very fortunate in the good-old United States, where we can push a button and talk to someone in English. Most of the time, anyway.

There is essentially no radar coverage in South America, except around large cities. Where there is radar, they don’t use it en route, because aircraft will soon be out of coverage again, so they are forced to fall back on timed separation at all times, and the old-fashion position reports (which most American pilots have never done). To be fair, arrivals and departures are sometimes vectored in the terminal area at low altitude.

In seven years of my operating on that route, there were five incidents where other aircraft were definitely in “my airspace” by any standards. This is made worse by those countries who consider a national airline a matter of pride, and whose crews take short-cuts. In one of those, I watched a Lan Chile aircraft cross our track a mile or two ahead, at our altitude, close enough to identify the logo at night. Both Lan Chile and ATC denied it, for the aircraft was supposed to be crossing at a VOR about 60 miles behind us. They were giving phony position reports (in Spanish), and simply taking a big shortcut. I felt it prudent to climb a few hundred feet to avoid a huge bump from the wake. File a report, and it would never see the light of day. I did anyway, and never heard a thing.

In my opinion, it would be much safer to do away with ATC entirely in areas like this. In trying to “control” aircraft with the equipment they have, and the “skill” they demonstrate, they create danger. I’d feel much more comfortable going with random routes and altitudes and using TCAS for my own separation.