Air France 447, Airbus 330, Rio to Paris 1 June

First Published 1 June, but inadvertently deleted. It has been edited and re-posted today along with the accompanying comments. Thanx. Paul Miller

The Weather Channel displayed an inter-tropical convergence zone (ITCZ) satellite shot of the area at the time of AF447 passage through the area. The Sat shot showed large areas of high cloud tops. This suggests ongoing convective activity. Routine meteorological knowledge of the troposphere in the tropics places the trop layer at about FL600.

In laymen terms, the thunder-boomers were likely topping out at 60,000 feet. The coverage for the area looked as if a flight would have to pick its way though and might not be able to “stay on the track of the course.”

If this metro estimation is relatively correct, the violent convection turbulence, hail, lightning and precipitation would make the transit of any cell or area of cells on this track or this course to be extremely hazardous.

Additionally, one other hazardous character of convection in the tropics is very rapid cell growth. Cells can grow at rates in excess of 6000 feet per minute. This means that a cell could literally grow right up in front of you in what may have appeared on radar to be a clear area. Pilots who fly to South America from various Miami airline domiciles can verify this amazing metro phenomenon when in the tropical inter convergence zone.

Three other safety things are troubling to me though: If the Weather Channel can have this data available for presentation to me, while I am sitting in my den in my house on my TV, why doesn’t airline’s flight control dispatch have this current data available for presentation to the flightcrew in the cockpit real time, while in flight? Remember that the preflight briefing occurred about 5 hours prior to the thunderstorm area transit, the transit was at night and this ITCZ is extremely dynamic both vertically and horizontally.

Why are Convective Sigments merely passed to flight crew, without flight control route hazard analysis, on the presumption that only the flight crew in flight, are to plot each weather report and compare it to the flight path to determine the hazard? Is not the company a stake holder in this issue? Should not flight control determine if the activity is in the flight’s path and recommend the safest path around the severe convection?

Why isn’t this done on the ground where more resources are available?

Next, does Air France have a procedure whereby flight crew are required to avoid convective cells by 20-30 miles? Do Air France flight crews actually comply with such a procedure? Is it a procedure or is it a policy? At your airline, is this avoidance a policy or a procedure?

Can an airborne radar with perhaps a good 80 mile range be expected to be sufficient equipment to circumnavigate an area 200 to 300 miles in width? Once in clouds, how capable is an airborne radar, in comparison to ground based hourly sat photos and infra red cloud top imaging?

Lastly, I suspect that there were other flights in the area at the time, heading to Europe and other points. What did they see in terms of weather? What did the official weather agencies report? Did any coordination transpire to assist the flight crews? Was there any chance of weather radar from Brazil being transmitted to flights in the area?

Let’s see, Antoine De Saint Exupery wrote about this in his 1931 novel “Night Flight.” ISBN 9780156656054

[Opps, I forgot, The Patagonian Weather services set up in the mid 1920’s, may not have changed much. I wonder if the same guy may still be working there with a sandwich, thermos of coffee, pack of cigarettes and a sharp pencil.]

How many times have pilots heard some version of this statement? “It is not our job to advise pilots about what they are supposed to do. It is our job only to observe and report the weather, the cloud covering and rain.”

Initially Posted by Paul Miller at 9:25 AM, June 1, 2009
Edited and re-posted 2 June.

Published by Capt. Paul Miller

Aviation safety expert with 43 years in the sky

59 thoughts on “Air France 447, Airbus 330, Rio to Paris 1 June

  1. As I have always said and maintained in safety management: Nothing has ever been determined in a mishap investigation that could not have been determined outside of and before a mishap related to an ongoing hazard. The claim that lives have to be lost in order to discover the obvious hazards to safety is 100% and totally unsubstantiated by any and every aircraft mishap investigation. Quite the opposite has been proven to be true time and time again in every mishap investigation. The hazards which caused the mishap were well known prior to the mishap and could have more easily and certainly more inexpensively been resolved prior to the mishap. The only role that the mishap played in the hazard resolution process was to finally change the minds of people in charge of an operation who steadfastly refused up until this point to recognize and respond to the hazard, known and most often widely known by most others involved in the operation.


  2. The statement I wanted you to see was pertaining to the radar and its use on the AF flight immediately behind AF447. Presumably, the fight 7 minutes behind, as stated in earlier articles:(Quote from the preceding ATW News article)"… the pilot of that following aircraft reported that he crossed a turbulent area that had not been picked up by his radar and "he avoided a much worse [area of turbulence] by manually increasing the sensitivity of his radar." "This seems to suggest that the second AF flight had an onboard radar with the capability of "attenuation adjustment."


  3. Attenuation control may have been available as you speculate. Also, with gain, tilt and other filters an operator can vary both the signal outbound and the interpretation of the return reflection to get a variety of radar display presentations. And one has to do this as the flight progresses enroute and also to examine various altitudes, decibel reflectivity and changes in the storms during approach to the storm area. Also, at 35,000 feet altitude a plane will see a changing reflection of the storm as the antenna gets closer and rounds the horizon. So the antenna location is changing, the distance is changing and the convective activity is changing, all at the same time and all at rapid rates! Therefore a depiction more than a few minutes old is of little value.


  4. Also, building cumulus with vapor not yet falling in precipitation can present a smaller less ominous echo to a radar, even though the turbulence, especially the rapid and voluminous lifting, can be extremely rough, violent and sudden. So many times a small echo can yield a big jolt. A flight crew has to remember that the radar shows rain, but the wings and fuselage see wind. Rain itself is not a serious threat.


  5. Bill, on the subject of attenuation, I have known it as a reference to the outbound signal. So I would interpret an attenuation control as capable of adjusting the strength of the outgoing beam, vs adjusting the gain or amplification of the incoming beam reflection.


  6. But in any case, it is often a great help to have a third eye from the sky helping the crew to get a clearer pix of what lies along the flight path now.


  7. Here we are, several months past the mishap with Air France: Have the pitot tubes been changed on all of their applicable planes? Have their dispatch office revised their weather avoidance procedures? Is Air France, and are other airlines allowing lawyers to maneuver legally in courts with these issues, in lieu of allowing safety managers to make the changes needed immediately?


  8. A number of US airlines who fly the AB330 are now in the process of replacing their pitot systems. That is good.I hope that they also upgrade their pilot to dispatcher communications as well to ensure thunderstorm avoidance along the file paths of flight.


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