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Indonesia: Adam Air Crash

Unspun complains about the lack of crisis management training in Indonesia after observing the way the authorities handled the crash of an private airline plane. Relatives were given conflicting messages on the status of the plane by different parties. “The first rule of anyone handling a crisis-like situation is to establish the facts. You establish the facts by verifying reports from several sources before going public with it. This is what the Transport Minister Hatta Rajasa failed to do when he blindly announced that the wreckage of KI 574 had been found and that there were 12 survivors.”

10 comments

  • indonesian guy

    let’s help us to get this disaster over.. we love peace, and i’m sure.. so do you!

  • I read in the Toronto Globe and Mail that a portion of the fin (vertical stabilizer) was found and the left tail stabilizer nunber 65C25746-76.

    This must be the elevator part.

    I googled the part number without the dash number and it is effectively the elevator of a Boeing 737.

    I am a structure’s engineer, M.Sc. In aircraft design at Cranfiled university.

    There is very little information available. So much to speculate as to what could have happened.

    However, based on the best facts available.

    There was a storm with gust winds up to 130 kph according to pilot’s report.

    The plane suddenly disappeared from radar signal without warning.

    Not much has been found from the wreckage for weeks until parts of the tail were found.

    Here’s a scenario:

    When planes get lost mid-air the sequence of failure is key.

    With climate change the impact is warming up of the atmosphere which means more energy in the air and therefore more turbulences that manifests itself into gusts (lateral gusts and vertical gusts relative to an airplane).

    For a commercial airliner (as opposed to a jet fighteray), flight control crtical components are designed (sized) based on fatigues loads encountered over the life of the aircraft in flight and on take-off and landing. What dictates the thickness of tail section parts are the gust fatigue loads. Vertical gusts for the horizontal surfaces (elevator and especially its attachments) and vertical gusts for the vertical fin and the rudder.

    Airplanes are therefore sized at design based on a distribution of gust loads with a certain magnitude. They call it a frequency distribution or spectral density. IT Plots a given gust load magnitude and the probability of occurence in a given flight. Those gust load spectrum are based on a worldwide survey done in the 1960s and all the design curves used by aircraft manufacturers are based on this survey. In addition, the airplane gets tested for gust fatigue loads in a fatigue test rig and the load. Cycles input is simulated with hydraulic actuators (jacks) based again on the 1960 worldwide survey.

    The concern is that design guidelines do not appear to have taken into account, yet, the significant change is gust load magnitude and frequency of occurrence (especially the extreme gusts which now happen much more frequently than in 1960). This means that for current aircraft the calculated inspection intervals to check for fatigue cracks may not be short enough to pick-up critical damage during routine maintenance check-ups which means that flight controls on tails are more susceptible to in-flight fatigue failures.

    When a rudder is lost the pilot can recover the aircraft using differential thrust application between the engines on each wing (this has been proven with the loss of a rudder last year on a Air Transat flight leaving the Dominican Republic for Montreal). There are pictures of the damage aircraft on airliners.net website showing the missing rudder.

    However, when an elevator is lost (say the attachment hinges fail) the pilot cannot recover the aircraft because he lost control in pitch manoeuvre (up and down).

    The same thing can be said when the complete vertical fin is loss (with rudder). They call that fin separation and this happened in november 2001 on an Airbus A340 on American Airline flight. The failure was not attributed though to fatigue failure but to a flight load exceeding the static ultimate load case of the fin attachments at the rear fuselage interface. What is important to note is if there is vertical fin separation, it is fair to assume that the aircraft is not recoverable from the pilot.

    Now how to link this with the very unfortunate tragedy? From what has been found and most of all what is missing (the complete rest of the airplane).

    If there was a fatigue failure on the elevator, this is the first part that would come off the airplane, and the elevator would free fall back in the sea (in this case) without too much damage because it relatively stiff and light. Then, the aircraft becomes uncontrollable, dives into the ocean at high speeds and dives deep in the water and pulverizes so that very little of the aircraft ca be found at sea.

    If there was a fin separation or complete tail separation, the same thing applies. The tail or fin would come off first and crash at a different location far away from the bulk of the aircraft without getting pulverized. This is why it is likely that this section would be found first in the search for evidence.

    The big problem in all this is that gust loads in the atmosphere have worsened by increasing in in magnitude and frequency of occurrence due to climate change.

    Airplanes are still designed with the old data set of the 60s and the existing ones have not had their inspection time schedules updated to inspect more frequently in order to detect strucutural fatigue damage (cracks) before it could lead to catastrophic failure.

    To support this hypothesis, please review the following study sponsored by the FAA which concludes that the gust magnitude and frequency has singnificantly changed so that the design guidelines used by aircraft manufactuters must be brought up-to-date for both new designs and for inspection of existing commercial fleets.

    The report was published in 1999 and prepared by the university of Dayton Ohio.

    They instrumented commercial airliners across the world with accelerometers to measure the statistical distribution of atmospheric gust loads as a fonction of altitude and geographical location.

    With that comprehensive information in hand, they should be in a position to update the 1960’s survey and then make recommendations for updates to design requirements and inspection requirements.

    I have yet to find where this is now.

    One thing is sure is that with global warming tail sections of transport aircraft are much more vulnerable than before and I predict that there will be increase effort after this accident to improve our understanding of the changing state of flight tubulences to ensure flight safety.

    There has not been a lot of fatigue failures in-flight in the past. However, with the Air Transat and the tragic Adam Air disaster, past remarquable trend is no guarantee for future impeccable records.

    Fatigue investigation of aircraft structures is going to need more emphasis I do believe. Please remember the Aloha multi-site damage in-flight failure over hawai due to corrosion and fatigue in the fuselage lap joints which lead the fuslage to sip somehow like a can of tuna. Remarquably, the pilot landed the aircraft. This is because of this accident that passengers are asked to wear safety belt at all times, as a result of the findings of the ivestigations.

    In closing, let me bring a dose of relativism into this. I have put up a credible scenario base on the minute facts available very early in the process. It is very possible that I could be wrong because there are thousands of possibilities to look for in this accidentinvestigation.

    However, my hope is this. That I have given you some excellent initial leads to search for and to demand explanations to authorities. You have the right to know about the context of today. If the scenarios put forward are not the cause, please insist on more information.

    If the scenarios are possible, then you have a chance to contribute toward the improvement of design standards and maintenance practices worldwide so that the safety record of air traffic remains what it is and has been, excellent overall.

    Hoping this help looking in a first direction.

    Sincerely, and with my deepest condoleances for the relatives of victims.

    Louis

  • Edward

    Hi all i’m from indonesia.

    There has been a scenario, that the actualy explode in midair. thats explain by the ELBA signal was appear in two different places.

    Is that possible to happen ?

  • Hi,

    Yes it is possible. If the tail section severes up to the rear bulkhead and if the bulkhead fails then you have catastrophic rapid (instant) decompression. Cabin at 35K feet is a pressure vessel.

  • I did not provide the report reference in the comment #2. Here it is:

    Report UDR-TM-1999-00003, March 1999, “An Evaluation of Continuous Atmospheric Turbulences Field Parameters Based on Commercial Aircraft Measurement”, University of Dayton Research Institute, Structural Integrity Division, Dayton, Ohio.

    Sponsor: US Department of Transportation, Federal Aviation Agency, Office of Aviation Research.

    The URL to download the report is:

    http://www.udri.udayton.edu/NR/rdonlyres/D51F88D0-83ED-4CB5-97E-567456393079/D/TurbFieldParaEvaluation.pdf

    Key excerpts are:

    “The present turbulence descriptions are based on pre-1961 VGH data obtained from commercial and military aircraft”

    CONCLUSIONS and RECOMMENDATIONS

    “The results of this study show that the method used to determine average absolute gust spectra does affect the derived values of the turbulence field parameter P.”

    “The results of this study suggest a MAJOR difference in the operation of modern commercial aircraft from the operations on which the FAR turbulence field parameters were based”

    “… And serious considerations should be given to changing the turbulence parameters presently used in the aircraft industry and specified in the FAR.”

  • hi… guys !

    it’s been 18 days, and we still got nothing.
    all we got is just small parts of the plane, and part of cabin that was totaly wrecked, like it was decompressed or some thing.

    even the US naval ship could not get any clue, so.. the hopes are getting thin here.Even the black box is not yet to be found.

    so any one get any idea, where cloud be the ship is now ? its no where near the site where the ELBA signal was deceted..

    is there any evey anything like this happend before ? a plane just gone , and all we found just a small remain of it ?

    we just pray for the best for now……

  • Thank you very much to Mr Bakrie.

    Salam Hangat

  • ooh.. there some thing i forget to tell, did any one know who found the rear stabilizer, he’s a local fisherman, his name is Mr.Bakrie (the one that writen on comment #7)

    and he got 50 million rupiahs reward for the gov.

    luck guy

  • good news !!!!
    we have found the location of hte balck box !! but now we are facinng another problem, it was found in around 20000 meters below sea surface.
    Now we still don’t know how to retrive the black box, which we all think, it was there with the rest of the plane parts.

  • Mark Lacas

    Please get your facts right! The air transat incident made ABSOLUTLY NO USE of differential thrust whatsoever,Official transport canada report,The fight departed from Cuba, not the DR . American airlines does not operate A 340 type aircraft It was an A300
    thank you
    Mark Lacas
    Captain Air Transat

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