{"id":5926,"date":"2009-06-05T00:17:51","date_gmt":"2009-06-04T22:17:51","guid":{"rendered":"https:\/\/spanish.martinvarsavsky.net\/?p=5926"},"modified":"2009-06-05T22:43:29","modified_gmt":"2009-06-05T20:43:29","slug":"dije-en-su-momento-como-creo-que-fue-el-accidente-spanair-ahora-cuento-como-creo-que-fue-el-af-447","status":"publish","type":"post","link":"https:\/\/spanish.martinvarsavsky.net\/?p=5926","title":{"rendered":"Dije en su momento c\u00f3mo creo que fue el accidente Spanair. Ahora cuento c\u00f3mo creo que fue el AF 447"},"content":{"rendered":"

Esto es lo que escrib\u00ed<\/a> poco despu\u00e9s del accidente de Spanair.<\/p>\n

Aunque no tengo m\u00e1s informaci\u00f3n sobre el accidente de Spanair, por todo lo que le\u00ed la causa del siniestro del avi\u00f3n de Spanair del 20 de agosto fue simplemente un error humano. Me lo imagino as\u00ed: un piloto, mientras le\u00eda la lista, le pregunt\u00f3 al segundo si hab\u00eda puesto los flaps\/slats en take off, y el otro dijo que s\u00ed, pero lamentablemente se olvid\u00f3 de activar la palanca y cuando escucharon los avisos (que no se sabe a\u00fan si los escucharon o no), no pudieron abortar. As\u00ed de sencillo. As\u00ed de tr\u00e1gico. As\u00ed de r\u00e1pido. Se que puedo estar equivocado en mi an\u00e1lisis, pero por el calor que hac\u00eda durante el despegue (yo hab\u00eda despegado de la misma pista dos horas antes), por ir a tope de pasajeros y combustible, por el comportamiento del avi\u00f3n que solo vol\u00f3 unos pocos segundos, todo indica que el avi\u00f3n trat\u00f3 de despegar sin flaps\/slats y se estrell\u00f3 e incendi\u00f3 resultando en la horrible e innecesaria muerte de 153 pasajeros.<\/em><\/p>\n

En este art\u00edculo dec\u00eda que cre\u00eda lo que a\u00fan creo, que simplemente los pilotos despegaron sin flaps\/slats y se estrellaron al no poder generar sustentaci\u00f3n suficiente un d\u00eda de mucho calor. Pero tambi\u00e9n dec\u00eda que era incre\u00edble que se dise\u00f1aran aviones que pudiendo medir la temperatura, el peso, y muchas otras variables, que le dejen a un piloto despegar sin flaps\/slats y estrellarse. Que todos cometemos errores, pero que los aviones tendr\u00edan que estar dise\u00f1ados para prevenirlos. Es m\u00e1s, muchos lo est\u00e1n, pero no el MD-82.<\/p>\n

Ahora, con todo el respeto a las v\u00edctimas y sabiendo que esto es una hip\u00f3tesis y que puedo estar totalmente equivocado, esto es lo que creo que le pas\u00f3 al avi\u00f3n de Air France.<\/p>\n

El avi\u00f3n volaba de noche. De noche no se ven donde empiezan y terminan los CBs (nubes huracanadas en forma de hongo con hielo, agua y rayos). Los pilotos vieron que el tiempo estaba malo en su radar, pero creyeron que pod\u00edan evitar los CBs. Quiz\u00e1s calcularon mal y creyeron que el radar apuntaba para abajo cuando los ten\u00edan adelante, ya que volaban a FL350. La cuesti\u00f3n es que se metieron por error en el CB de su vida. El avi\u00f3n empez\u00f3 a sacudirse m\u00e1s de lo que nunca hab\u00edan vivido. Asustados, decidieron cortar motores porque en turbulencia los motores hacen que todos los movimientos sean m\u00e1s bruscos, pero cortaron demasiado y entraron en p\u00e9rdida. O quiz\u00e1s entraton en p\u00e9rdida porque el CB tiene cambios enormes de temperatura, vientos, presi\u00f3n pero digamos por razones meteorol\u00f3gicas. Entraron en p\u00e9rdida en medio de la noche, en un CB y probablemente porque la p\u00e9rdida depend\u00eda tambi\u00e9n de como soplaban los vientos en el CB que pueden haberse puesto a favor y dejarlos sin sustentaci\u00f3n donde hay muy poca atm\u00f3sfera (p\u00e9rdida quiere decir volar despacio y los aviones no pueden volar despacio porque se caen). <\/p>\n

En esta situaci\u00f3n el tema es qui\u00e9n sabe sacar a un Airbus 330 de una p\u00e9rdida extrema. El problema de los aviones, que la gente s\u00ed sabe es que si vuelan muy lentos se caen, pero lo que la gente no sabe que si vuelan muy r\u00e1pido y en medio de grandes turbulencias pueden tener da\u00f1os estructurales graves o hasta partirse. En esos casos es crucial que el avi\u00f3n no caiga en picado, porque se acelera al punto que se puede desintegrar. Yo creo que los pilotos –que no eran pilotos acrob\u00e1ticos– no pudieron sacar el avi\u00f3n de p\u00e9rdida antes de que se partiera. Adem\u00e1s, puede ser que primero perdieron el horizonte, que es el instrumento indispensable para volar nivelados. De d\u00eda, afuera de nubes se ve el horizonte. De noche con luna tambi\u00e9n se ve, o, inclusive sin luna (yo perd\u00ed el horizonte una vez volando con un muy buen piloto y salimos del berenjenal), pero de noche y en un CB, una p\u00e9rdida sin horizonte es una condena de muerte. Adem\u00e1s est\u00e1 el tema de que hay que ser un verdadero genio de piloto para poder volar un avi\u00f3n a mano a 35 mil pies en medio de una tormenta. Si se les desconect\u00f3 el piloto autom\u00e1tico o si en desesperaci\u00f3n lo desconectaron ellos las cosas se ponen casi imposibles porque a FL350 hay poqu\u00edsima sustentaci\u00f3n y poqu\u00edsima diferencia entre ir en p\u00e9rdida o ir demasiado r\u00e1pido.<\/p>\n

Tambi\u00e9n puede ser que el avi\u00f3n en s\u00ed sufri\u00f3 una falla muy grave que lo hizo imposible de volar sin que los pilotos hayan hecho nada ellos. Esto es poco probable, pero no imposible. En ese momento puede ser o una p\u00e9rdida de control por parte de los pilotos, o una p\u00e9rdida de la capacidad de hacer volar el avi\u00f3n o que el avi\u00f3n se pueda volar, pero sin instrumentos y de noche y que los pilotos pierdan el control igual. Al acelerarse, creo que el Airbus se parti\u00f3 en el aire o que sufri\u00f3 un da\u00f1o grav\u00edsimo mientras volaba, pero tambi\u00e9n puede haberse estrellado contra el mar y desintegrado en el impacto.<\/p>\n

El tema de si se parti\u00f3 en el aire o en impacto se sabr\u00eda si hubieran llegado al accidente poco tiempo despu\u00e9s o si el avi\u00f3n ca\u00eda en tierra. Pero llegando d\u00edas despu\u00e9s y con poco debris muy desparramado es muy dif\u00edcil saberlo, y como el avi\u00f3n no ten\u00eda un GPS tracker y los pilotos se vieron en una tan mala que ni pudieron declarar emergencia, no se supo donde se accidentaron.<\/p>\n

El tema de este accidente es como el de Spanair. Por un lado, es error humano (no poner flaps vs entrar en p\u00e9rdida), pero, por otro, de vuelta uno se pregunta c\u00f3mo los pilotos no est\u00e1n m\u00e1s asistidos. En el caso de Spanair por un avi\u00f3n que simplemente no despega cuando no tiene los flaps puestos, que cuando se acelera no acelera, y en el caso del AF por un avi\u00f3n que no tiene meteorolog\u00eda en tiempo real, no tiene una base de AF que est\u00e1 asesorando todo el tiempo por tel\u00e9fono satelital a los pilotos, sigui\u00e9ndoles por GPS trackers y que le dice qu\u00e9 hacer o le ayuda a tomar la decisi\u00f3n de c\u00f3mo evitar los CBs (las radios son mucho m\u00e1s lentas que los tel\u00e9fonos para hablar en una emergencia).<\/p>\n

Tambi\u00e9n est\u00e1n las condiciones. En el caso de Spanair calor de mediod\u00eda, que hace que la sustentaci\u00f3n sea m\u00ednima y en caso del AF, noche de tormenta en medio de CBs. Los CBs se ven y son much\u00edsimo m\u00e1s f\u00e1ciles de evitar de d\u00eda. Me atrevo a decir que de d\u00eda este accidente no ocurr\u00eda y que si realmente te preocupa el tema debes elegir vuelos que crucen el Ecuador durante el d\u00eda.<\/p>\n

Ahora sigo con el tema de los pilotos acr\u00f3baticos. Tengo un muy buen amigo, Joshua Ramo, que escribi\u00f3 un gran libro sobre los pilotos acrob\u00e1ticos. No Visible Horizon. Recomiendo comprarlo aqu\u00ed<\/a>. Ahora ,es interesante que se llama No Visible Horizon porque eso es el peor problema de un piloto. Pero los pilotos acrob\u00e1ticos no hacen otra cosa que sacar a aviones de las posiciones m\u00e1s incre\u00edbles, sin horizonte. \u00bfEs absurdo pedir que los pilotos comerciales hagan acrobacia a\u00e9rea en su entrenamiento?<\/p>\n

Yo lo poco que hice me dieron unas ganas de vomitar incre\u00edbles. Ni por broma (o ni de co\u00f1a, como se dice en Espa\u00f1a) podr\u00eda ser piloto acrob\u00e1tico. Pero si de mi dependiera poner la vida de 200 personas en las manos de alguien, yo s\u00ed pedir\u00eda que un piloto comercial sepa sacar a un avi\u00f3n de una p\u00e9rdida como las que entran los aviones acrob\u00e1ticos. En cambio, hoy en d\u00eda ser piloto comercial pasa por estudiar teor\u00eda, teor\u00eda y m\u00e1s teor\u00eda. Especialmente en Europa. Pero la teor\u00eda que tanto se pide en Europa y que hace casi imposible sacarse el t\u00edtulo a pilotos, de poco sirve adentro de un CB en p\u00e9rdida. La acrobacia si que sirve.<\/p>\n

A mi si me parece que los pilotos comerciales tendr\u00edan que hacer cursos de acrobacia a\u00e9rea. Ahora, quiz\u00e1s el avi\u00f3n en s\u00ed no era volable, en cuyo caso nadie lo podr\u00eda haber salvado. Pero, como dije, creo que esto es posible, aunque menos probable que que los pilotos no hayan sabido salir de la p\u00e9rdida antes que el avi\u00f3n se acelerara y se hiciera luego imposible de volar.<\/p>\n

Termino advirtiendo que puedo estar totalmente equivocado sobre lo que ocurri\u00f3 con el avi\u00f3n de AF, as\u00ed como podr\u00eda haberlo estado en el de Spanair. Pero este es mi blog y me atrevo a decir lo que pienso pese a estar siendo muy criticado por el tema, como si opinar sin ser el investigador oficial del accidente es un acto de poca \u00e9tica y respeto a las v\u00edctimas. Aclaro que mi \u00fanico deseo es que este tipo de accidentes en el cual se cae un avi\u00f3n y no se sabe ni c\u00f3mo, ni por qu\u00e9, ni d\u00f3nde y todos se mueren, no vuelvan a ocurrir.<\/p>\n

Agregado posterior. Gracias a Jos\u00e9 Miguel Vives por llevarme a un foro de pilotos de Iberia<\/a> donde enlazan a este art\u00edculo <\/a>que dice mucho de lo que digo pero mejor explicado. Es interesante lo que dice el concepto de la esquina del ataud \u00abcoffin corner\u00bb en la que se vuela para ahorrar combustible. Los aviones a 35 mil pies volando lento para ahorra combustible tienen poqu\u00edsima maniobrabilidad y est\u00e1n cerca de la p\u00e9rdida y todo se complica cuando entran en una nube huracanada.<\/p>\n

:
\n<\/p>\n

Difficulty Locating Lost Jet\u2019s Flight Recorders Shows Need for Upgraded Technology<\/p>\n

Tue, Jun 2, 2009 \u2014 David Evans<\/p>\n

Articles, Featured<\/p>\n

The search is on for the cockpit voice and flight data recorders (CVR\/FDR) from the Air France A330 lost on the night of 31 May. The airplane, with 216 passengers and 12 crew and operated as flight 447, was lost in an area of known thunderstorm activity in the so-called inter-tropical convergence zone (ITCZ) on a night flight from Rio de Janeiro to Paris.<\/p>\n

The airplane is believed to have been lost slightly less than halfway from northwest Brazil to Cape Verde, off the coast of Africa. In other words, it plummeted to the ocean pretty much in the middle of nowhere, and the recorders lie in pretty deep waters \u2013 about 13,000 feet below the surface. The lack of ground radar coverage in oceanic airspace means it will be difficult to pinpoint exactly where the airplane went down. To be sure, the recorders have an electronic beacon to facilitate their recovery, but the signal is fairly short range, and the batteries are only good for about 30 days.<\/p>\n

This accident may galvanize efforts to equip airliners with the means to offload critical flight data in real time, thereby avoiding the necessity of searching for flight data recorders weakly broadcasting their location at the bottom of a vast ocean.<\/p>\n

Thunderstorms and \u201chard\u201d turbulence was reported in the area, and the aircraft was at 35,000 feet and loaded with fuel for the flight to Paris. During harsh economic times, when jobs are at risk, pilots will assist in making operations more economical by flying right up in the so-called \u201ccoffin corner\u201d of the flight envelope despite their heavy weights.
\n\u00abCoffin corner,\u00bb where the margins for controlled flight are minimal. Note that at heavier all-up weight (AUW), the envelope for \u00abcoffin corner\u00bb is considerably, and dangerously, expanded.<\/p>\n

\u00abCoffin corner,\u00bb where the margins for controlled flight are minimal. Note that at heavier all-up weight (AUW), the envelope for \u00abcoffin corner\u00bb is considerably, and dangerously, expanded.<\/p>\n

That is, they will fly where the margin between aerodynamic stall and Mach buffet is minimal to yield the best fuel economy (air nautical miles per pound of fuel). When that is done in the area of 55,000 foot cloud tops of the ITCZ, the environment-related controllability hazards become very real. To be sure, even at night, one can fly around the intense cells of thunderstorm activity visually (or by radar), dodging the storm tops.
\nCruising the \u00abcoffin corner\u00bb on the speed tape (shown at left) of the primary flight display. The red stripe is the over speed and the yellow stripe is the low speed resulting from a high wing load.<\/p>\n

Cruising the \u00abcoffin corner\u00bb on the speed tape (shown at left) of the primary flight display. The red stripe is the over speed and the yellow stripe is the low speed resulting from a high wing load.<\/p>\n

However, it\u2019s also possible to strike clear air turbulence associated with the ITCZ, or to stumble into a thunderhead that wasn\u2019t seen ahead (courtesy of its electrical activity and flashes of sheet lightning).<\/p>\n

All that\u2019s needed is some turbulence or a sudden air temperature change (affecting both airspeed and thrust output) and the pilot could well be faced with a sudden loss of control on a dark night. Only a few thousand feet below are the solid, unfriendly could tops of the ITCZ\u2019s solid thunderstorm activity. Once inside that maelstrom of cloud below, with its severe turbulence, hail, lightning, and so forth, a successful recovery from an unusual attitude would be problematic.<\/p>\n

It appears that the Air France jet flew through three key thunderstorm clusters. Temperature trends suggest that the entire system was at peak intensity. From a turbulence perspective, cold spots would be the areas of highest concern as they signal the location of an active updraft producing new cloud material in the upper troposphere. Planes are clear of the most dangerous weather throughout a tropical system except when directly above an active updraft area. It is estimated that the aircraft flew through about 75 miles of numerous updrafts lasting about 12 minutes of flight time. Identical tropical storm complexes have probably been crossed hundreds of times over the years without serious incident, but not heavy flights risking coffin corner encounters to save fuel.
\nFalse-color satellite image of weather at the time Air France flight 447 made its last transmission. The active thunderstorm areas are defined by small-scale mottled areas of cold cloud tops. Temperature trends suggest that the entire system was at peak intensity. From a turbulence perspective, those cold spots would be the areas of greatest concern, as they signify the location of an active updraft producing new cloud material in the upper troposphere.<\/p>\n

False-color satellite image of weather at the time Air France flight 447 made its last transmission. The active thunderstorm areas are defined by small-scale mottled areas of cold cloud tops. Temperature trends suggest that the entire system was at peak intensity. From a turbulence perspective, those cold spots would be the areas of greatest concern, as they signify the location of an active updraft producing new cloud material in the upper troposphere.<\/p>\n

Although an airliner is built to survive severe turbulence encounters with \u201cmerely\u201d broken equipment, components, and injured passengers and crew while the wings stay on, the stresses involved in recovering from an upset or loss of aerodynamic control at altitude can quickly exceed those parameters.<\/p>\n

Having to recover from an upset at night while possibly descending through or into the convective clouds that put you there in the first place reduces everything to a strong odds-against situation.<\/p>\n

Recall also that the A330 is a fly-by-wire (FBW) airplane that is limited in its maneuverability by control laws. That feature is intended to forestall pilots from getting into unusual attitudes, but it can also limit a pilot\u2019s ability to recover from inverted or spinning situations. Control laws cannot, however, prevent cataclysmic overstress on the airframe.<\/p>\n

The ACARS (airborne communications addressing and reporting system) message sent automatically by the aircraft to the airline operations center, indicating serious electrical failure and other system problems, may well be consistent with the aircraft being overstressed and breaking up. Only a few seconds would be needed for the generated faults to self-precipitate such a message. The cascade of systems failures is about what would occur from a structural failure following an overstress stemming from a high-level loss of control (i.e., a coffin corner stall-spin entry). The \u201cadvisory regarding cabin vertical speed\u201d tends to confirm a high rate of descent \u2013 and nil cabin pressurization because of hull rupture \u2013 towards the end of the episode.<\/p>\n

A few items already come to mind that merit investigators attention. Is Air France (and, obviously, other airlines) allowing or instructing crews to get high early and stroking that razor\u2019s edge of coffin corner while still at heavy all-up-weight and vulnerable to loss of control? Is the Airbus fly-by-wire design, with its hard limits on the crew\u2019s control inputs, more vulnerable than others during unusual attitude recovery? Do crews practice tangles with coffin corner in the simulator?<\/p>\n

And if the recorders are not located, a reconstruction of the events leading to the airplane\u2019s loss will be vastly complicated. Investigators may wish to pursue various technologies for transmitting data as it\u2019s captured. This is what is done for space systems (the Space Shuttle, for example, does not have \u201cblack boxes,\u201d but transmits information continuously).<\/p>\n

It is time to move beyond archiving aircraft data in shockproof, fireproff, waterproof boxes, according to Sy Levine of Topanga, California. \u201cThe present system is analogous to having a patient in intensive care being monitored; however, few people look at the data until the patient dies or after release from the hospital,\u201d he said.<\/p>\n

The concept for downloading data in real-time was born of personal experience. As the former chief engineer for a major aerospace company, Levine was stimulated to think about the problem when one of the engineers who worked for him was killed in the 1994 crash of US Air flight 427. The paucity of data enormously complicated the investigation.<\/p>\n

In Levine\u2019s concept, the aircraft transmits a near-constant flow of information on its status. As an example of the integration of information he envisions, items like low fuel would cause a symbol to be generate on the air traffic controller\u2019s display.<\/p>\n

Basically, Levine\u2019s concept would combine multiple inputs in the aircraft with real-time communications via satellite of sensor data to a ground station. His approach \u2013 which he has dubbed the Remote Aircraft Flight Recorder & Advisory Telemetry (RAFT) system \u2013 would bring flight\/cockpit recorder information out of an old recorded-on-the-aircraft methodology and plug it into a near real-time database at a remote station.
\nInstead of recording cockpit voice and flight data on the airplane, the RAFT concept would send the information, via satellite, to a ground station for quick access.<\/p>\n

Instead of recording cockpit voice and flight data on the airplane, the RAFT concept would send the information, via satellite, to a ground station for quick access.<\/p>\n

As his concept paper explains:<\/p>\n

\u201cThe global telemetry of the [flight data recorder] parameters allows aircraft monitored data to be simply and safely stored on the ground, thus making it readily available for aircraft statistical analysis programs that enhance air carrier efficiency and safety. Also, in the advent of a crash, it provides a timely accurate global estimate of the downed aircraft\u2019s location for search, recovery and hopefully rescue operations.\u201d<\/p>\n

In this case, retrieval of human remains is probably all that can be hoped for \u2013 and recovery of the CVR\/FDR, whose archived data is useful only if it is pulled up from the dark waters of the Atlantic Ocean. With telemetry, that critical information would already be available.
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<\/div><\/div>","protected":false},"excerpt":{"rendered":"

Esto es lo que escrib\u00ed poco despu\u00e9s del accidente de Spanair. Aunque no tengo m\u00e1s informaci\u00f3n sobre el accidente de Spanair, por todo lo que le\u00ed la causa del siniestro del avi\u00f3n de Spanair del 20 de agosto fue simplemente un error humano. Me lo imagino as\u00ed: un piloto, mientras le\u00eda la lista, le pregunt\u00f3 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[],"_links":{"self":[{"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=\/wp\/v2\/posts\/5926"}],"collection":[{"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5926"}],"version-history":[{"count":0,"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=\/wp\/v2\/posts\/5926\/revisions"}],"wp:attachment":[{"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5926"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5926"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spanish.martinvarsavsky.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5926"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}