Tom Horne

A studied look at AF 447′s wx

June 5, 2009 by Thomas A. Horne, Editor At Large

We’re going through the predictable stages of speculation regarding the Air France 447 crash. Interesting how first theories/rumors are nearly always wrong-and that goes for any airplane crash. But Tim Vasquez, a noted meteorologist in Norman, Oklahoma, has done a masterful job of compiling what data exists concerning the mesoscale situation that AF 447 may have encountered. If you want to see what a classy meteorological case study looks like, check it out online http://www.weathergraphics.com/tim/af447/

What’s interesting about Vasquez’s analysis is that the variables seem pretty much ordinary for the inter-tropical convergence zone. CAPE (convective available potential energy–a measure of potential storm severity) values were nowhere near the values we see in midwestern storm complexes. Vasquez estimates cloud tops as being 56,000 feet, which is significant given AF 447′s cruise altitude of 35,000 feet. The worst turbulence may have come after the airplane exited a storm cell.

Data is sparse over the crash region, so Vasquez uses GOES-10 and Meteosat-9 satellite imagery to come up with likely scenarios. His verdict: turbulence was the culprit. But, as always, the jury is still out, and may never come in, unless those voice and data recorders are recovered. My guess is that this will be a landmark accident, in that live data-streaming from the cockpit to ground-based computers will make on-board CVRs and DVRs things of the past.

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18 Responses to “A studied look at AF 447′s wx”

  1. John V. Kjellman Says:

    It has long seemed to me that every commercial plane should have one button that could be pushed to begin transmitting everything that goes to the CVR over a special radio channel, and that pilots should be trained and required to push that button as soon as they realize they might be in serious trouble. Such a procedure would answer a lot of question in many accident cases, especially in accidents like this one.

    No one expects pilots to stop focusing on the problem at hand in order to radio a commentary back to headquarters about the problem they are facing, but one second to push one button is doable.

  2. Herb L Says:

    Subject Airbus 330 Accident

    First let me preface my commentary with the following:

    I am a FAA Licensed Pilot, but I have no experience as an (ATP) Airline Transport Pilot or in flying heavy multi-engine commercial type equipment. I, like everyone else (including professionals) must reserve judgment and not make any hasty rush to judgment pre-determinations regarding this incident. If I must adhere to this reservation, then why is no one else subscribing to this restrained practice?

    The information coming out in recent days re: this Air France Airbus 330 accident has a bad smell to it and did so from day one. In fact, the aroma is getting more pungent by the day. Lots of people are jumping to lots of different conclusions and affixing blame already. I have even seen the blame being laid at the feet of George Bush (Honest!) and Global Warming among the many other alleged causes I have seen published.

    It typically takes months, often years to find and gather enough evidence to make a final determination in these type accidents that happen over land masses. When they happen over deep Blue Ocean Waters, they are even much harder to solve. Sometimes, a final factual determination supporting a specific conclusion and cause(s) cannot ever be reached.

    This accident might very well be one of those that can never be factually solved.

    The ocean depths in the crash area are reported to vary from a few thousand feet to 4 miles or more and the bottoms are not flat, but deeply canyoned. If the black boxes even survived the aircraft breakup and subsequent fall from altitude, they may be resting thousands of feet below the surface in uneven terrain. If the Transmitted Signal Pinging cannot be detected, then they, most likely will not ever be found and recovered. The Black Boxes are Key Evidence and especially with this incident in-that it happened over deep water and the aircraft wreckage is now sunken or scattered over thousands of square miles etc.

    As I offered in an earlier message, the Weather “Only” scenario/causation is problematic for me and the many, including trained professionals and for all those of us who have a keen interest in all things aviation. If you look at (historically) all the Flight Operations data over-time including crashes/incidents there is very little precedent for this Weather “Only“ scenario for a large transport type aircraft traveling at normal cruising speeds at Flight Level Altitudes so as to be ripped out of the sky and downed by turbulence, lightning, violent updrafts/downdrafts etc. etc. There are plenty of incidents close to the ground at lower altitudes in arrival or departure operations, yes, but not like this incident.

    1. Essentially, Weather Alone – Possible but Doubtful!

    2. Weather in conjunction with other supporting type Human or Engineering Factors – Yes

    Since the Black Boxes may not be found to support any factual type conclusion, it appears that the many who have a vested interest in this incident are already developing suppositional causes with built-in defenses. Why? It’s called Culpability and Liability. If Mother Nature and all her known ferocity are to blame, then we have an Act Of God Incident that essentially gets everyone else off the hook who otherwise may have some intrinsic culpability and liability exposure for other types of cause and effect scenarios.

    Weather as the sole cause could be very convenient for some.

    Everyone in this incident including the flying public has something to gain or something to lose. Who might this be you ask here’s who:

    1. The French Government
    2. Airbus and its Consortium, Contractors, Suppliers, Maintenance Group etc.
    3. The Flight Crew and their possible actions or non-actions
    4. Insurance Underwriters
    5. Law Firms/ Trial Lawyers
    6. Did I forget anyone?

    And the beat goes on!

    In the end, the Flying Public (you and I) and Families of Passengers gets screwed if there is any rush to judgment here blaming weather when a multitude of other scenarios are highly suspect (based upon past precedent) and that could actually be to blame. I am not insinuating any cover-up on the part of anyone at this point in time, but finding or not finding those black boxes and/or any other physical type evidence affects many people or groups in lots of different ways. Some positive, some not!

    Here are two comments I found (I found many) in this News Forum by Professional ATP Guys. There are many others (like these) that are being offered by Professional ATP Class Pilots in other groups just like these:

    Quite a few “experts” chattering. I’m not being sarcastic or, condescending. But, there is more to this picture than weather.

    I am a MD-11 captain with 32 years of experience. While I would hate to absolutely state that weather was not the MAIN cause of this tragedy….I seriously doubt that it was. Barring mechanical failure(s) these aircraft can transverse weather systems safely for the most part. The auto pilot disconnect is NOT something out of the ordinary in such conditions. Fact is that disengaging the auto pilot is a normal procedure in heavy or, severe turbulence. The pilot “hand flies” so that the aircraft does not overstress as it might do if the A/P remained engaged. It takes an awful lot for an aircraft to self destruct and I am not saying it did not happen but, experience suggests there was something more afoot in this instance.

    As a former 707 pilot, we had two major directives regarding thunderstorms and turbulence. Slow down to “penetration airspeeds, well above stall. Use radar to avoid thunderstorms, even if it means changing course, fuel capacity being a consideration for diverting to a nearer airfield. Airline Companies may be encouraging pilots to press the schedules ahead of safe flying. Thunderstorms, like icebergs should be avoided at all costs.

    I hope we can hear from more Professional ATP Types both Civilian and Military alike to get there different perspectives and experiences on this incident, especially commentary with the Weather Only scenario.

  3. TR1 Says:

    Can any pilot comment on the possibility of the heating elements in the Pitot tubes failing leading to incorrect airspeed readings as they iced over?

  4. Jay Levin Says:

    I’m recently retired after 30 years with the largest airline. Last aircraft was 757/767. I’ve been astonished at how many “experts” are putting out opinions on what could’ve been the problem. A lot of cats in sandboxes. Follow the money.

    The weather, from what I understand, was no worse than an average springtime day in the midwest. Yet some are asserting that this was “killer” weather that was impenetrable. Sounds like a lawyer. In 45 years of flying, I never met a pilot who would deliberately ignore his weather radar and take his own tush through a big red thunderstorm. The only thing that is fairly sure so far is that the airplane was not in one piece when it arrived at the surface of the ocean. Unless Airbus or Air France are hiding data, there is no way to speculate until the other 95% of the data is recovered with the boxes.

  5. Jay Levin Says:

    Regarding the pitot heaters failing: There are three separate pitot systems on Boeings, and I imagine on Airbus as well. They each have separate heaters and they are powered by separate electrical sources. They talk to separate central air data computers. The computers compare notes and toss out erroneous signals. For all three pitot heaters to fail is a mathematical near impossiblity.

  6. Jim Baldwin Says:

    The ACARS reports shout electrical failure loud and clear. If the 330 elctrics are similar to the 320 then ESS AC and ESS DC failure will produce 90%of the symptoms recorded by ACARS. With air data computers failed the pitot readings are irrelevant.
    Fancy flying in Cu-nimb without EFIS,standby horizon failed, no radio,no transponder,no intercom and limited controls (worst case scenario, stabiliser trim and rudder) I don’t!!

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