Reiteradamente he escrito sobre el (mal) trato al que es sometido el viajero en los aeropuertos y en los aviones. Yo soy de los que inicialmente me creía que los equipos electrónicos y los teléfonos móviles podían poner en riesgo la seguridad aérea, como nos decían. Comprensiblemente crédulo. Ahora, nos permiten usar los equipos electrónicos, sin que nadie nos pida disculpas por las veces que hemos sido absurdamente reñidos y, mucho peor, en Estados Unidos están estudiando permitir el móvil porque no tiene ningún riesgo. Yo he llegado hasta aquí: no van a conseguir que me crea que lo que hasta ayer era arriesgado para la seguridad, a partir de ahora no lo es. Seré crédulo pero no tonto.
Antes, sin embargo, déjenme que les cuente cómo están las cosas hoy mismo.
En diciembre del año pasado, la Federal Communications Commission (FCC) de Estados Unidos remitió una comunicación al Departamento de Transportes en la que le indicaba que se podía permitir el uso del móvil en los aviones, sin ninguna restricción. ¿Y la seguridad, y los riesgos, y esas azafatas indignadas cuando nos veían con un móvil en la mano? Nada, que se puede permitir el móvil. Pero no lo puede permitir la FCC sino el Departamento de Transportes (DOT) del Gobierno, que es el competente.
¿Qué ha hecho el DOT? Pues lanzó un un estudio para consultar qué piensan los implicados. Pero no qué piensan en razón a la seguridad, sino sobre si molestará o no a los otros viajeros, si es o no conveniente que se mantenga el avión como un lugar libre de teléfonos, etcétera. Katrhyn Thomson es la consejera que ha sido encargada por el Departamento de Transportes americano para este asunto. Esta mujer, en una conferencia pronunciada en el International Aviation Club de Washington hace unos días, dijo que el ministerio está trabajando en una propuesta de normativa que se publicará en diciembre. Transportes debe confirmar o rectificar la propuesta que le ha llegado de la Federal Communications Commission que en diciembre del año pasado le remitió un pedido para cancelar las restricciones existentes. O sea, para la FCC no es necesario mantener las limitaciones que estaban en vigor. Y la FCC es la comisión técnica, la que analiza estas cuestiones desde el punto de vista de sus implicaciones.
¿Qué hace ahora el ministerio?
El ministerio en febrero, dos meses después de recibir la propuesta de la FCC, abrió un periodo de consulta para saber qué es lo más adecuado. Pero las compañías aéreas están indignadas porque acusan al ministerio de meterse en un asunto que no es suyo. Afirman que deberían dejar a las compañías adoptar la decisión que quieran (permitir o no el uso del móvil), en función de sus estrategias comerciales. Cada una debería saber qué ofrecer a sus clientes.
El ministerio (departamento) de Transportes ha dejado entrever por dónde irán sus preferencias. Anthony Foxx, su titular, ha dicho que está en contra del uso de los móviles porque cree que los pasajeros y la tripulación están mayoritariamente en contra. Jeffrey Shane, consejero de la IATA, indica que las compañías no están pidiendo que se permita el uso del móvil en los vuelos, incluso añade que algunas han confirmado que lo prohibirán por su cuenta, pero que sí quieren tomar sus propias decisiones.
Hoy hasta 13 compañías ya ofrecen teléfono a bordo en Estados Unidos, pero no conectando con tierra firme sino mediante un servicio específico. Sin embargo, afirman, la mayor parte de los viajeros se limitan a conectarse al servicio de datos o envían SMS y muy pocos hacen llamadas.
¿Y Europa?
No, Europa no existe. En Europa vamos a remolque de lo que diga Estados Unidos y, encima, les copiamos lo que menos nos interesa. En Europa aún tenemos tripulantes que se ponen como motos porque usamos los móviles cuando el avión está en tierra, cuando en Estados Unidos esto ya no es un problema, pese a que siga prohibido.
A estas alturas, es razonable pensar que el transporte aéreo se ha convertido en una especie de experimento social en el que se trata de demostrar cuánto absurdo está dispuesto a soportar un usuario. Por ejemplo, ¿podemos retirarle un botellín de agua cerrado aduciendo que puede ser explosivo? ¿Agua explosiva? ¿La misma agua que se puede comprar dentro de la zona de seguridad del aeropuerto? ¿Podemos prohibirle el uso del móvil porque el avión se puede caer, para al día siguiente permitírselo sin dar explicaciones? Hemos estado durante una década sin poder usar equipos electrónicos durante los despegues y aterrizajes, por temor a las interferencias. Cuando los americanos finalmente decidieron que eso no tenía sentido, aquí en Europa dijimos que sí, que no tiene sentido, tratando al viajero como si no tuviera capacidad para pensar y asociar ideas. Quizás un día descubran que el botellín de agua es tan botellín de agua antes de los controles de seguridad como después.
Pero primero tienen que hacer este descubrimiento los americanos.
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Amador: ¿ha contrastado usted sus afirmaciones con profesionales del sector, o son, una vez más, opiniones disfrazadas de verdades emitidas por el plumilla sectario de siempre?
Hay, y lo digo para información de los lectores, no de usted ya que la veracidad de lo que torpemente intenta transmitir le importa un bledo, decenas de miles de casos documentados de interferencias electromagnéticas causadas por móviles y otros aparatos electrónicos, que han afectado a instrumentos y a diferentes sistemas de otros tantos aviones.
La industria, además, ha invertido (y sigue invirtiendo) cantidades ingentes de recursos en el blindaje de esos instrumentos y sistemas, para hacerlos inmunes a esas interferencias que, según usted, son una invención de un cerebro trasnochado.
Vuelve usted a desacreditarse solo.
¡Si es todo un invento!
Cada mañana, un gabinete de sádicos alecciona a los comandantes de cada avión, en técnicas de martirio al pasajero.
Mientras tanto, los ejecutivos de las compañías aéreas, que lo que quieren es vender billetes, se reúnen en congresos dirigidos a adoptar medidas que hagan que los posibles pasajeros desistan de comprar esos billetes ante el mal trato al que son sometidos.
Sr. Amador; si no fuera por la vergüenza ajena que provoca su lectura, sus "artículos" serían divertidos de puro ridículos.
Es increible hasta donde puede llegar la ignorancia.
Ponga usted el teléfono movil junto al televisor aunque este apagado y rápidamente acuda a un chaman o espiritista a que limpie su casa de entes de ultratumba tras oir ese tac taca tac taca tac unas cuantas veces.
Es lo que sugiere jaimito en esta ocasión. Porque tienen que ser entes sobrenaturales los que producen el ruidito ya que sabemos que las emisiones electromagnéticas no tienen ningún efecto sobre los equipos electrónicos según la plebe sabe.
El que haya tecnologías diferentes en diferentes tipos de avión es irrelevante dicen, aunque en algunos de ellos son ordenadores mucho mas complicados que su televisor los que controlan los motores, mandos de vuelo e incluso la dirección y los frenos cuando ruedan por tierra.
Y por si faltara algún detalle siempre aparece el "ciudadano que no puede permitir que pateen sus derechos" que se indigna cuando alguien le recuerda que tiene que cumplir con las leyes que es lo que hacen los auxiliares de vuelo de forma mas o menos exaltada. A fin de cuentas los tripulantes también son personas que tiene la obligación de exigirle el cumplimiento de la norma y defender su propia vida ya que ellos si han visto en multitud de ocasiones como un teléfono, portatil o CD ha estado relacionado con alguna despresurización, u otro fallo en el avión.
Pero claro si la FCC no tiene problemas con los teléfonos es que deben ser seguros. Pues no. Ellos simplemente dicen que no afecta a sus intereses económicos pero no aseguran su inocuidad.
Exacto, señor amador. Según la misma teoría no entiendo por qué en 1927 volar de Madrid a Barcelona llevaba tantas horas. Seguro que el sector aéreo lo hacía por fastidiar. Y por qué hace dos siglos había que lavar a mano.quien escondia las lavadoras. Qué malo es tener que escribir sin tener nada que contar
... con móviles encendidos la va a hacer su puta madre.
.... por escribir 1000 palabras cada semana cuando nada se tiene que decir.
HOW REAL IS THE PROBLEM
OF HIGH INTENSITY RADIATED
FIELDS?
Electromagnetic interference may come from inside the plane or from outside it. What makes the internal sources a matter for concern is that they are so close to the systems they might affect; what makes the external sources a matter for concern is that, despite their distance, their power level can be very high. Although the internal and external overlap in their effects (see box), in general the external sources involve much higher power levels, even after traveling some distance; hence they may have more serious effects. Called HIRFs -- which sometimes stands for High Intensity Radiated Fields and other times High Intensity Radio Frequency -- the external signals come either from huge ground transmitters such as radio, radar, and television antennas, or airborne transmitters such as high-powered radar and radio on military planes.
The distinction between "ground" and "airborne" transmitters is sometimes instead referred to as a distinction between "fixed" and "intermittent" transmitters, words that somewhat obscure the possible effects of military equipment but have the advantage of making clear why the airborne sources of HlRFs may be harder for pilots to avoid. Because a ground transmitter is "fixed," its location is marked on most aviation maps and can be avoided by the pilot. If a pilot on a particular flight has an electrical problem and, upon reviewing it, discovers the plane was at that moment flying in the area of a powerful ground transmitter, there is a possible concrete cause to investigate. An airborne, intermittent transmitter, in contrast, cannot be as easily avoided; nor, if an anomalous electrical situation emerges, is there usually any way to know what military craft were nearby and what particular transmitters were in use.3
Beginning in 1989, the FAA started requiring the aviation industry to increase its attention to the problem of HIRFs and to place higher levels of shielding on planes. Some members of the aviation industry, such as Monte Mitchell, executive director of Aircraft Electronics Association, were upset, not just because they had not been consulted and would now encounter larger costs, but because the problem was being described as "a grievous hazard" without any actual facts being given. Furthermore, the requirements for increased shielding were only being applied to new planes, not to those already in the air. "Does HIRF represent a dire and immediate threat to civil aircraft operating in the nation's air space?" Mitchell asked, calling attention to the FAA's failure to cite any accidents or to ground any untested airplanes already flying. If it does, he continued, "then the FAA is guilty of malfeasance in not grounding the entire civilian fleet before lives are unnecessarily lost to this environmental threat."4
This past summer, the FAA issued a Flight Standards Bulletin about the problem of High Intensity Radiated Fields. The policy statement couples HIRFs (electromagnetic interference originating from sources outside the passenger plane) with lightning (which is itself a powerful electromagnetic event).5 This coupling suggests the seriousness with which HIRFs are regarded: the bulletin explicitly notes that electromagnetic interference from electronic devices carried by passengers-- which is much weaker -- is dealt with in a wholly separate policy statement. Although the bulletin specifies the source of HIRFs as radar, radio, and television transmitters, it does not mention the military. But a 1994 NASA study does. It notes that "the cause of High Intensity Radiated Field events may often be inadvertent effects on civilian aircraft of high-powered military operations or covert drug interdiction"; it specifies that military jammers and electronic countermeasures equipment can affect key systems on commercial planes flying through the same geography; and it observes that the problem turns up most frequently in regions such as the Caribbean where there is "a large amount of American shipboard and airborne surveillance."6
The NASA study makes it clear that this kind of electromagnetic interference can lead not just to disruptions in airplane navigation and communication systems but to "loss of aircraft and life." A false reading on an instrument may itself have dire consequences if a pilot is approaching a runway in a difficult terrain or a crowded urban area. But electromagnetic interference may also introduce a false command into the plane's electrical system, suddenly instructing its rudder to move, or (at higher power levels) disrupting a plane's control surfaces -- its rudder and wing flaps -- by burning out a circuit. Military planes may themselves at times become vulnerable to interference from other military craft.
A seven-month-long Air Force study concluded in late 1988 that "thousands of conflicts" among radio waves used by the three branches of the military had produced grave outcomes. Electromagnetic interference can jam equipment, burn out electric circuits, and even prompt explosions (as when, driving near a blasting area, one is instructed to turn off a car radio). According to Colonel Charles Quisenberry. the director of the study, it can also " 'affect the electrons within the aircraft's flight controls as well as its fuel controls,' . . . putting a plane into an uncommanded turn or dive or turning off its fuel supply."7 Some forms of interference, Colonel Quisenberry stated, "are very, very critical -- some cause aircraft to crash."8
Although most concrete instances remain classified, Colonel Quisenberry specified two. Because of electromagnetic interference, Black Hawk helicopters have periodically crashed and killed their crews. The crashes appear to have occurred five times in the six years between 1982 and 1988, with twenty-two deaths. "The Black Hawk was shielded at a very low level -- it was known ahead of time that its shielding was inadequate," Colonel Quisenberry stated.9 (Even before the Air Force study, one senior Army aviator had gone on public record about the Black Hawks: "EMI is causing these aircraft to flip upside down and crash and kill everybody aboard.''10) The aircraft called F111s have also been extremely vulnerable. One fell near Libya in 1986, killing two airmen; five other F111s were disabled during the same mission. Colonel Quisenberry reported that electromagnetic interference was a possible cause of the F111s' problems.11
How serious is electromagnetic interference in the eyes of the military? So serious that attempts to address the problem have for years been evident throughout the construction of their planes, ships, and ground vehicles. The choice of outer materials is shaped by concerns about incoming signals. Navy planes that land on carriers are built to withstand high-electromagnetic fields.12 If the outer shell of a plane proves insufficient, new layers will be added: extra shielding costing $175 million now covers the flight control computers on the Black Hawks.13
The attempt to remedy the problem is visible, too, in the addition of electric filters. While planes and ships may have accidental emissions of electromagnetic waves, at least one plane in each branch of the military has been explicitly designed to bring about dire outcomes through radar and pulses: the Navy Prowler (based at Whidbey Island, Washington), the Air Force Compass Call (based at Wright-Patterson in Ohio), and the Army Common Sensor (based at Vint Farms, Virginia). The problem is how to damage the sensing and signaling capacities of the enemy's plane without damaging similar capacities on your comrade's plane. In 1993, Congress authorized special funding for a series of high-frequency and very-low-frequency electric filters to be fitted onto Common Sensor and Compass Call by 1998. The purpose of the filter, as it is phrased in electronic warfare literature, is to "reduce fratricide.''14 The Navy Prowler, at one point also scheduled for an upgrade, has not yet received it even though its tactical jamming system is on record as straying toward civilian planes or ships.15
Efforts to control incoming and outgoing signals often determine the architecture of military craft. The cruisers and destroyers with Aegis equipment for guided missiles -- called Aegis Guided Missile Cruisers and Destroyers -- form the backbone of the country's surface fleet since they are responsible for defending the large carriers. The Aegis-equipped ships built during the 1980s are in the class called Ticonderoga CG-47: both the USS Vincennes (which accidentally shot down an Iranian Airbus in 1988) and the USS Normandy (applauded for its actions in Bosnia in September 199516 but later a source of concern to the public when it turned up in the vicinity of TWA 800) belong to this class. Starting in the late 1980s and continuing into the 1990s, the CG-47 has been replaced by a class of destroyer called DG-51 Arleigh Burke: its key difference from its predecessor with respect to its Aegis equipment is that its Combat Information Center has been placed "below the waterline [where] all electronics are hardened against electromagnetic pulse."17
The attempt to avoid electromagnetic interference, finally, not only has a pervasive effect on the choice of materials and the shape of aircraft but has even begun to prompt a systemwide reform: the shift from "fly-by-wire" to "fly-by-light" -- from electric wiring to fiber optics (which operate by encoding data inside light beams confined within transparent fibers that guide them to their destination). Why are NASA. the Department of Defense, McDonnell Douglas, Allied Signal, Honeywell, Raytheon, Lear Astronics, and so many other companies engaging in fiber optics research despite the staggering labor in making the sweeping, countrywide changes that a conversion to fiber optics would involve? The answers they give are straightforward. Fiber optics (among many other virtues such as their light weight and their capacity to carry large amounts of data rapidly) are immune to electromagnetic interference.18 As Raytheon President and former Aircraft Chairman Arthur Wegner observed, fly-by-light will eliminate "problems with high-intensity radiated fields . . . . that have plagued designers of fly-by-wire systems, and 'brought a few of their airplanes out of the sky.' "19
The introduction of new shielding, new shapes, and new systems designed to protect a craft from fraternal emissions will also, of course, help to protect that craft against enemy emissions should the United States enter into combat with foreign forces.20 Inadvertent interference from a fellow plane may serve (assuming one survives the encounter) as an early warning, calling attention to a path of electronic vulnerability that might later, be intentionally pursued by an enemy jammer or microwave weapon. But the particular focus here has been on problems accidentally inflicted on our military craft by their own companions (cases in which, to use Colonel Quisenberry's language, "We did it to ourselves"21) and on those repairs whose lineage can be traced back to an incident of electromagnetic interference by US equipment.22 It is hard to comprehend why High Intensity Radiated Fields should be of sustained concern to the military and yet not be even a subject of discussion when a civilian plane goes down. It is certainly true that military planes spend more time in the company of other military craft than do civilian planes (and greater exposure time increases the chance that one day a stray emission may accidentally imperil them). But it is also true that civilian planes do sometimes (as in the case of TWA 800) end up in the vicinity of military craft. That many hundreds of thousands of plane flights take place without incident should not deter inquiry into the accumulated evidence of the dangers that may result from electronic military transmissions.23
In military and scientific research, the phrase "electromagnetic compatibility" is used almost interchangeably with the phrase "electromagnetic interference" since the two are mirror terms: the first expresses the aspiration to control or eliminate the problems expressed by the second. Since 1961, the Pentagon has had a 600-person agency located in Annapolis called the ECAC, Electromagnetic Compatibility Analysis Center, a reminder that the problem of electromagnetic inconsistency (which may seem insubstantial because seldom spoken about aloud) is real enough to warrant the spending of substantial public money.24 Another division of the Pentagon is called the Joint Electronic Warfare Center. Even equipment that is designed to bring about intentional interference can have unintended effects. In response to the Air Force's 1988 study of the way radio waves have jeopardized airborne craft, the Pentagon initiated a $35 million three-year-long investigation,25 whose results have never been made public. American citizens need to request that this Pentagon study, as well as the earlier Air Force study, be either opened for the public record or, at the very least, made fully available to all those charged with investigating TWA 800 and other inexplicable falls from the sky, such as USAir 427 that in 1994 went down near Pittsburgh, and the 737 that went down over Colorado Springs in 1989.26 American citizens who paid for these studies -- and for the Black Hawk computer shielding, the redesign of the Aegis, the research on fiber optics -- need now to be made the beneficiaries of this research.
The idea that citizens should benefit from the scientific research they fund is a principle with many applications. During the week-long public hearing about TWA 800 in Baltimore this past December, Jim Hall, the chair of the National Transportation Safety Board, raised the point repeatedly, returning to it whenever it became clear that research successfully completed on behalf of military aviation had somehow never reached the agencies responsible for civilian aviation.27 Unshared military research on wiring, fuel gauge residues, and bonding inside central fuel tanks prompted Hall's patiently repeated queries. But the need for open information is even more pressing in the case of electromagnetic interference -- a subject not yet investigated by the NTSB -- because the phenomenon involves computations whose difficulty is likely to seem overwhelming not just to a population hearing about them for the first time but, as will be suggested below, even to researchers who have dedicated many years to solving them.
We do not at present have a picture -- a background -- against which to see, or even think about, the part that might have been played by electromagnetic interference in the fall of TWA 800. Yet that background picture exists. It exists in the physical examples collected in the seven-month-long 1988 Air Force study and the empirical evidence gathered in the three-year-long 1989-1991 Pentagon studies. (The request for this information leaves to the side the vast amount of military research undertaken for electronic warfare that analyzes intentional interference precisely calibrated to interrupt the electronic equipment of an opponent,28 as well as research carried out to test the survivability of our own craft to willful electronic disruption by an enemy.) What the Air Force and Pentagon studies of inadvertent interference will provide is concrete examples of power levels, distances, and forms of equipment that have caused crashes: the power level and distance of the transmission source that, for example, caused Black Hawk helicopters to "flip upside down"29; these may vary greatly from crash to crash and may in turn collectively be very different from the power level and distance ,of the Navy jamming equipment that may have caused the F111 to crash; in turn, a different set of power levels and distances may be involved in the many cases Colonel Quisenberry alluded to but could not voice.
With the help of such information, a clear account of the physical features of electromagnetic accidents will begin to come into view: the cases in which all electronic systems cease simultaneously; the cases in which a black box ceases to record; the cases in which, either as an early or a late incident in the accident, a craft explodes before hitting the ground (as the F111 in the Libya mission eventually exploded into "a fiery ball" before, like TWA 800, disappearing into the sea). At present, there exist in the public domain only two kinds of information. The open literature occasionally provides clear statements about power levels and distances (a rare example is a book by Clayborne Taylor and D. V. Giri, High-Power Microwave Systems and Effects, that describes both truck-mounted and ship-mounted systems; it gives the radiated power as it moves from the site of transmission to distances ranging from 100 meters to 32 kilometers30); but this literature does not specify equipment by name or identifying number that enables one to know where, or even whether, it is currently in use.
Conversely, we have concrete information about equipment now in use, with only the haziest information about power levels and distances: the Sea Hawk helicopter (the Navy version of the Black Hawk) received shielding long before the Black Hawk, and until that shielding was added, pilots were under strict instructions to stay "some significant number of miles" from transmission sources.31 This information is helpful since it specifies that electromagnetic interference takes place at distances measured in miles (rather than, for example, "some significant number of feet"), but the number of miles is classified.
The NASA study makes it clear that this kind of electromagnetic interference can lead not just to disruptions in airplane navigation and communication systems but to “loss of aircraft and life.” A false reading on an instrument may itself have dire consequences if a pilot is approaching a runway in a difficult terrain or a crowded urban area. But electromagnetic interference may also introduce a false command into the plane’s electrical system, suddenly instructing its rudder to move, or (at higher power levels) disrupting a plane’s control surfaces — its rudder and wing flaps — by burning out a circuit. Military planes may themselves at times become vulnerable to interference from other military craft.
A seven-month-long Air Force study concluded in late 1988 that “thousands of conflicts” among radio waves used by the three branches of the military had produced grave outcomes. Electromagnetic interference can jam equipment, burn out electric circuits, and even prompt explosions (as when, driving near a blasting area, one is instructed to turn off a car radio). According to Colonel Charles Quisenberry. the director of the study, it can also ” ‘affect the electrons within the aircraft’s flight controls as well as its fuel controls,’ . . . putting a plane into an uncommanded turn or dive or turning off its fuel supply.”7 Some forms of interference, Colonel Quisenberry stated, “are very, very critical — some cause aircraft to crash.”
Obviamente, nuestro "periodista" no ha leído nada sobre el tema en español, cuanto menos en inglés.
Otro bodrio más de nuestro experto en aviación y/o en conflictos laborales que osan molestar al señorito.
Veo este tema en Preferente y la dura reacción de personas que probablemente sean expertos en aviación y me quedo sorprendido. ¿Cómo se puede escribir algo tan fuera de lugar?
Sin embargo, me informo mejor y sí, salvo algún matiz, es verdad que la FCC ha propuesto permitir el uso del teléfono a bordo. Es decir, básicamente lo que leo es que esta información es correcta. Entonces me pregunto ¿qué ocurre para que haya gente dispuesta a acosar a este medio a partir de creencias y no de datos? Basta leer esta noticia para comprender que Preferente está sustancialmente en lo cierto.
http://online.wsj.com/news/articles/SB10001424052702303653004579212210178774516
En todo caso, es muy lamentable este tipo de público. ¿O no?
Bajo el título: "Chistes de Jaimito"
Sr. Amador,
lo que hace el calor.
Venga.. a la vuelta otra.
Saludo.
Cualquier noticia que afirme taxativamente que un telefono movil no puede provocar interferencias con instrumentos/sistemas del avion DENTRO del que vuela, es falsa, se diga en español o en ingles.
Ota cosa son los aparatos electrónicos equipados con "modo avion" que, una vez activado, los convierte en un elemento "pasivo", incapaz de emitir o recibir nada.
En cuanto a su juicio sobre lo lamentable del publico de nuestro ínclito Amador, debo decirle que difiero de usted al considerar como única cosa lamentable, todas y cada una de las inciertas, indocumentadas, sesgadas, sectarias y, probablemente, pagadas intervenciones del tal Jaime Amador.
¿os habéis dado cuenta de que todos los comentarios van en la misma dirección mostrando al señor amador una vez más que su guerra contra los profesionales del sector aéreo no tiene una base muy sólida y todos los comentarios tienen un no me gusta?
será el señor amador que no quiere entender?
Que se pone del lado de las empresas (y en contra d ellos trabajadores) cuando hay huelgas en cualquiera de los sectores del transporte, y que se hace eco de cualquier noticia pseudo-científica si ésta sirve para enfrentar a cualquier grupo de clientes (u opinión publica) contra cualquier grupo de trabajadores.
Desgraciadamente para él, es tan evidente en sus planteamientos, y tan deficiente en su técnica como escritor, que su credibilidad, en el caso de que hubiese gozado de ella en algún momento, se evaporó hace ya tiempo al compás de los bodrios que ha ido publicando.
Esta página habla mucho de los pilotos de aviones de este país. Y no precisamente bien. Cerrados, arrogantes, incapaces. La cuestión en este asunto es bien simple: yo leo el Wall Street Journal y lo que dice no difiere sustancialmente de lo que dice esta noticia. Doy a Google y veo que básicamente el informe del FCC al DOT americano es así. ¿Pero qué clase de gente lee este digital que no tiene el menor respeto por la evidencia?
Vaya, ya me lo imaginaba: si un coche no tiene problemas con el móvil, qué le va a pasar a un avión. Además, no me creo que cuando despega o aterriza logre aislarse de la impresionante cantidad de ondas que nos cruzan por todos lados. Lo que pasa es que los pilotos, que no son más que conductores de autobuses que vuelan, creen que son un poco superiores a los demás.
Pero ¿estos no son los mismos que nos prohibían usar el ipad al despegar?
Los tres ultimos posts reflejan la actitud de algunos, que tratan de denigrar a los profesionales de aviación españoles llamándolos incapaces, o calificando a los pilotos de "conductores de autobuses con alas". Pues bien, se les han expuesto las razones en detalle en el post de las 1624 del 16 de agosto. Lo que ocurre es que, pribablemente, su nivel de inglés o su capacidad de comprender un artículo técnico son deplorables. Por eso recurren siempre a lis mismos lugares comunes. Basta con leer al que equipara la complejidad de un avión a un automóvil...
Y si, Maria, se te prohibira usar tu iPad, o cualquier dispositivo movil, si la tripulacion lo requiere. Y no vas a poder hacer nada al respecto. ¡Ah!, me olvidaba recordarte que el incumplimiento de las órdenes de la tripulación técnica puede incurrir en poner en peligro la seguridad de la aerobave y pasaje. Y eso pude causarte problemas. Allá tú...
Y los ministros de hacienda son contables, los cirujanos cardiovasculares fontaneros, los traumatólogos mecánicos, los actores de Hollywood bufones, y los cantantes multimillonarios juglares.
¿Y usted? ¿Qué es usted, señor Toni?
Pues Toni para empezar es un ignorante atrevido y además envidioso, por lo que desprenden sus palabras. Probablemente también sea un infeliz.
Salud Toni !!
Jo con los pollos. No tienen ni zorra idea de lo que son las telecomunicaciones y se piensan que por ser pilotos (conductores de autobuses que vuelan) nos pueden dar lecciones a los demás. Yo pocas veces he visto gente tan arrogante. Creo que lo mejor que os ha pasado es O'Leary, que os ha empezado a tratar como lo que sois. Y ahora también Iberia va por el mismo camino. Igual en 20 años os convertís en gente normal, que entiende que sabe de algunas cosas y calla cuando afecta a lo que no sabe.
Amador, yo que tu, después de como te han puesto.... me dedicaba a contar cuentos para niños que esta de moda otra vez y es menos peligroso.
Everybody knows how difficult listening to the radio or watching TV becomes when someone is using the vacuum cleaner in the next room. The vacuum cleaner causes significant interference with the radio signal. I used to live in a house in Kensington, CA, with an electric garage door opener, activated from the road by a small radio device carried in my car. The door would occasionally open by itself, early in the morning, on some rainy days when SFO was using RWY 19 for arrivals, and the flight path came more-or-less overhead. Now, there's an anecdote. I don't know it was aircraft transmissions; I don't know it wasn't a passing taxicab whose driver was talking to base; I don't even know it wasn't a fault in the door opening mechanism. We may presume that the system was not very well shielded from electromagnetic interference, and it is certainly not certified to the same rigorous standards as avionics (`aviation electronics').
Nevertheless, there are similar worries in aviation at the moment. Passengers use electronic devices on board aircraft, including some such as cellular phones that they shouldn't in any case be attempting to use, and pilots have reported anomalies with their navigation equipment that seem to correlate with use of personal electronics in the cabin. An overview of the technical issues may be found in (Hel96).
There have been to my knowledge no reports so far of interference with electronic flight control on the Airbus A320/330/340 series or the Boeing B777. These systems are shielded very well against electronic signals, because they have to fly through radar beams and other electromagnetic fields that may be occasionally very strong. There is nevertheless some experience with electromagnetic interference with electronic flight controls. Five crashes of Blackhawk helicopters shortly after their introduction into service in the late 1980's were found to be due to electromagnetic interference from very strong radar and radio transmitters with the electronic flight control systems (1). So concern about this phenomenon is not purely the result of speculation. It has actually happened, and it is appropriate to be concerned about the possibility of similar phenomena in transport aircraft.
Bruce Nordwall (Nor96), writing in Aviation Week and Space Technology in September 1996, reported on the topic of an RTCA report to the FAA Administrator. At the request of the FAA, RTCA Special Committee 177 was formed in 1992 to look into the possibility of interference with aircraft systems from electronic devices operated by passengers during flight. Such devices include laptop computers, Gameboys and, more insidiously, portable personal telephones employing cellular technology.
Nordwall reported the RTCA advisory group to be worried that no group was testing or systematically tracking the potential effect of passenger electronics on avionics. The group was also concerned that the flying public is not being educated about the potential hazard, and that the airlines must largely figure out how to deal with the issue themselves. Most airlines in the US already prohibit use of passenger electronics of any sort below 10,000ft altitude. There is most concern for the future; that rapid increases in the technology of personal communications may allow passengers to bring aboard with them, and inadvertently or surreptitiously use, devices such as personal satellite phones that may be capable of significant levels of electromagnetic radiation. The RTCA report recommends developing and installing devices in aircraft cabins that could detect and locate potentially harmful radiation coming from within the aircraft. John Sheehan, the chairperson of RTCA SC-177, kindly provided the Executive Summary of SC-177's report, RTCA DO-233 (RTCA96). The Summary is included here as Appendix A.
Navigation systems are particularly vulnerable for two reasons:
they have parts devised to detect and act on signals coming from `outside';
radio-based systems are particularly susceptible to low levels of interference.
Aircraft control systems are located entirely within the aircraft and are shielded from absolutely any signals not coming from one of their own devices; they are also not radio-based, but are based entirely on electrical signals conducted through wires as are most computer networks (in the future, maybe also light signals conducted through glass-fibre cables). Navigation avionics, on the other hand, must have some designed sensitivity to environmental radio signals in order to perform their function. Nordwall says
THe antennas of radio-based avionics may be affected by [electromagnetic] field intensities of only microvolts per meter. But being outside the aircraft, the antennas get some protective attenuation from the fuselage of radiation originating inside the aircraft. Non-radio systems generally have higher signal levels, and so are less susceptible to low levels of interference.
The hull of a metal aircraft forms an effective electromagnetic boundary between the outside and the inside of an aircraft. Electromagnetic signals find it hard to get in, or to get out. That is why the navigation and radio antennae on an aircraft need to be placed outside the aircraft hull. But while outside they must be sensitive, the navigation electronics inside the hull can be in principle just as well and securely shielded as control avionics, because there is no reason at all for navigation systems to be sensitive to electromagnetic signals coming from inside the aircraft -- indeed, very good reasons for these systems to be very insensitive, namely, that there is lots of other electronics working there as well.
The Regulatory Environment
US Federal Aviation Regulation 91.21 prohibits the use of any portable electronic devices on board aircraft, with the exception of voice recorders, hearing aids, heart pacemakers, shavers, and any other device that the operator of the aircraft has determined will not cause interference with the navigation or communication systems of its aircraft:
91.21 Portable electronic devices
(a) Except as provided in paragraph (b) of this section, no person may operate, nor may any operator or pilot in command of an aircraft allow the operation of, any portable electronic device on any of the following U.S.-registered civil aircraft:
(1) Aircraft operated by a holder of an air carrier operating certificate or an operating certificate; or
(2) Any other aircraft while it is operated under IFR.
(b) Paragraph (a) of this section does not apply to--
(1)Portable voice recorders;
(2)Hearing aids;
(3)Heart pacemakers;
(4)Electric shavers; or
(5)Any other portable electronic device that the operator of the aircraft has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used.
(c) In the case of an aircraft operated by the holder of an air carrier operating certificate or an operating certificate, the determination required by paragraph (b)(5) of this section shall be made by that operator of the aircraft on which the particular device is to be used. In the case of other aircraft, the determination may be made by the pilot in command or other operator of the aircraft.
The regulation puts the responsibility firmly on an individual airline to determine that there is no interference. However, as Nordwall points out, `Compact consumer electronic devices have proliferated in numbers that defy cataloguing, let alone testing.' The question is what would constitute an appropriate `determination of no interference'. In contrast to the US Federal Aviation Regulations, the International Civial Aviation Organisation (ICAO) has no regulations relating to portable electronics.
US airlines implement a general ban on using any portable electronic devices (PEDs) below 10,000ft. According to former FAA associate administrator for regulation and certification, Tony Broderick, this action was first initiated by Northwest Airlines, and other airlines quickly followed suit. Broderick notes that use of PEDs during takeoff and landing phases is to be discouraged anyway, not only because of possible consequences of EMI but also to encourage passengers to pay attention to the cabin crew in case an emergency should arise during these critical phases of flight (Bro97) (a commercial aircraft is below 10,000ft usually only during the takeoff and landing phases of flight, and according to the Boeing statistics, 20.9% of all fatal accidents to jet aircraft have happened during takeoff and initial climb, and 46.6% during initial and final approach and landing (Boe96)). Broderick also believes that the FAA, in cooperation with the industry, will need to determine if there is indeed a problem with PEDs on board aircraft, and that it will soon become commonplace to have PEDs on board that are doing things (for example, transmitting) that their owners aren't really aware of.
Some Issues Particular to Cellular Phones
Cellular phones, often called Cellphones in the US and Handy's in Germany, are a particular source of problems because, regardless of whether they may interfere with aircraft systems, the technology on which cellular telephones are based precludes their effective use on aircraft. This applies to all cellular phones, including the analogue technology in the US and the digital GSM technology in Europe. It may be worthwhile first to explain the known problems associated with attempted use of cellular phones while flying.
The technology of cellular phones is based on small local ground-based reception areas called `cells'. A cellphone user is served by just one cell, and when reaching the boundary of a cell, will be `handed over' to another cell which (s)he is about to enter. The topology of coverage is based on the assumption that the user is on or near the ground, and it is a technical assumption on which the entire system is based that a user will be within `sight' of just one cell except when nearing a cell boundary. When in an aircraft, however, a user is within radio `sight' of many cells, simply because (s)he is way off the ground. An attempted call or reception from an aircraft would activate many if not all cells in the local area, which `breaks' the technology -- it causes many transmission problems and the system is disturbed. Therefore the various communication authorities, such as the US Federal Communications Commission (FCC), ban the attempted use of cellular phones while on board aircraft. However, such attempted use is not ipso facto rendered dangerous. It is technically inappropriate and antisocial, as well as mostly futile.
On Saturday 1 March 1997, German Transport Minister Matthias Wissmann was reported in the German and international press as wanting a fine and up to two years in jail for people attempting use of cellular phones on board aircraft. He was reported as saying that
In order to further increase air transport safety there will be new regulations in the use of these dangerous things [...] In future the use of electronic equipment by passengers in aircraft will be banned.
(Uhr97)
Herr Wissmann's comment mentions the danger of attempted cellphone use. He therefore seems to be speaking about the possibility of interference with aircraft systems, which if true is certainly dangerous, rather than simply the problem that it causes the cellphone technology to malfunction.
While one may applaud Herr Wissmann's proactive stance in addressing a potential hazard, one may also query the wisdom of publically declaring aerial cellphone use to be dangerous in the absence of any concrete proof. My colleague Prof. Dr. Klaus Brunnstein of the University of Hamburg, who avidly follows various potential public computer risks, commented that
[...] German law still forbids mobile communication (with specific exemptions) [...] It is interesting that airlines don't specifically refer to this law when announcing that [attempted use of] mobile telephones [is] not permitted on board.
(Bru97)
Brunnstein is not aware of any concrete proof of electronic interference on German aircraft, but reports that EUCARE has more than 60 pilot reports of potential cases of interference, including some with cellphones. He laments the anecdotal nature of these cases, since one requirement for accurate `forensics', as he aptly terms it, is verifiability of the source data.
General Worries on Interference
Nordwall reports that the RTCA Committee 177 inquiry found 137 `incidents' (pilot reports, anecdotes) reported either to them, or to the FAA/NASA Aviation Safety Reporting System (ASRS) program, or to the International Air Transport Association (IATA). VOR reception (2) was affected in 111 incidents -- by far the most common occurrence. From the 33 reports direct to RTCA, 21 incidents related to laptop computers and only 2 to cellular phones. Navigation systems were affected in 26 of those incidents; fuel systems, warning lights and propulsion reported one incident each. Rough correlation of suspect with effect by turning the suspect device on and off was found in 14 cases, on-off-on in 6 cases, and no correlation in 13 cases.
Some Anecdotes and Discussion
Jim Irving is a colleague who flies B737 aircraft for a major US carrier. He has an anecdote:
[...] One day departing Portland Oregon we noted that the FMC [Flight Management Computer] Map display showed a disagreement with the "raw data" VOR position. Our training is such that we would normally immediately switch over to "raw data" and assume the FMC was in error.
We would have done that except that it was a beautifully clear day and I looked out the window and was able to determine that the FMC seemed to be right on. I called back to the cabin and asked the flight attendants to check for someone using a cell phone or computer. A few minutes later they called back to say that a man had been using his cell phone and it was now off. Strangely (?) our VOR and FMC map now agreed.
Later in the flight the flight attendants called back and said that they had caught the man using his cell phone again but this time we had not noticed any problems, perhaps because we were in cruise far from the ground and not paying as much attention.
(Irv97),
André Berger (who also has a homepage) is a colleague who flies B737 aircraft for a major European airline and who has had first-hand experience of some of these incidents. While interference is not proven, he believes it gives considerable cause for concern; and that while it may be difficult to demonstrate the relationship using Brunnstein's `forensic' criterion, this could be due to the fact that the equipment needed to do so is not on board the aircraft at the times the incidents occur. Berger monitors the IATA confidential incident reports, and also has some experience of his own to contribute:
In our company we recently had a Localizer deviation (out of tolerances) on a B737-200 related to a GSM (mobile phone) being operated by a passenger (who was disregarding our company regulations). When requested by the cabin crew to switch off his GSM, localizer indications became normal. Is this scientific proof? Certainly not, but good enough for me as a captain to insist that all the electronic toys, computers, mobile phones, etc., are OFF during critical phases of flight. [...]
I had fuel indications on the FMC going crazy on board the B737, that returned to normal when all electronic stuff in the back was switched off. I suspect a "Gameboy" electronic game device to have interfered, but this is no more than a guess. No, I did not ask to switch the toy back on again and investigate more in depth as I was responsible for the safety of 140 passengers and this would have been extremely irresponsible! This is not a situation in which to do such testing! This [ever-present responsibility accounts for why] there is no "proof" of the relationship.
I also recall experiencing *impossible* mode annunciations on the FMA (flight mode annunciator) on B737. Having both the autothrottle AND the pitch channel of the autopilot trying to maintain speed (both in MCP SPD mode) for example, not programmed by the pilot (you cannot program that). After an expensive in-depth troubleshooting session by our maintenance department, the incompatible mode annunciations were traced to a ... faulty cockpit window heat wiring. This caused electronic interference with the auto flight system.
(Ber97.1),
Berger has also recounted two more incidents:
June 07, 1997. B737-300: *Verify position* was indicated on the CDU. Both IRS and radio position were correct, the FMC position was not. The difference rapidly increased to 8 nautical miles. After switching a GSM in the cabin from STBY to OFF, the FMC updated normally. FMC was correct for the remainder of the flight and on the return flight.
April 30, 1997. B737-400: During level cruise, the AP pitched up and down with ROC/ROD of 400 fpm indicated. Other AP was selected: no change. Cabin was checked for PC's and other electronic devices: nothing was found. Requested passengers to verify that their mobile phone (GSM) was switched OFF. Soon after this request all pitch oscillations stopped.
Just glitches or did interference really occur? Don't know, but EMI (electro-magnetic interference) is a problem that needs more research.
(Ber97.2),
Apparently, there are also some incidents with older aircraft. Here is Berger's response to a query from another colleague:
> Has anyone heard of EMI incidents involving older Aircraft, i.e. 707,
> DC9,747-200, where system signal strengths are larger, and a lot more
> are analog?
[There was one incident reported with a] B737-200. During approach to MAN (Manchester International, UK), the LOC for landing runway 24 oscillated and centered with the aircraft not on track (but offset), confirmed visually. Ground equipment was monitored and working normally. When a GSM in the cabin was switched off, all indications became correct.
(Ber97.3),
Frank McCormick, an aerospace engineering colleague who is also a FAA Designated Engineering Representative, wonders about the physics of such possible incidents:
The threat levels presented by the gadgetry in question -- personal computers, cellular phones, compact-disk players, hand-held video games and so on -- are mere background noise compared to the threat levels that must be demonstrated during environmental qualification testing [of the aircraft systems]. How could an FMC [Flight Management Computer] pass, say, DO-160C [standard certification] tests, yet lose its mind in the presence of a cell phone on standby?
(McC97),
and Peter Mellor, of the Center for Software Reliability at City University in London, reports that
The cabling on the A320 has not only been tested for resilience to "normal" EMI, but for its ability to withstand the much greater pulse that would result from the aircraft flying through a powerful radar beam, for example.
(Mel97),
While doubting that the suspected-EMI phenomenon is ubiquitous, McCormick suggests that some sort of systematic investigation could proceed by inviting protagonists (actual airplane, pilots, customer with suspect device) to participate in attempts to reproduce the incidents. Berger reports that in fact very few systematic tests are performed anyway: he asked a major portable phone manufacturer's representative what tests they performed for EMI from their devices in aircraft. The manufacturer performed none because use of cellphones is illegal in aircraft. Berger notes that nevertheless such tests are relevant, because these phones are frequently used surreptitiously or inadvertently on aircraft. He also notes that most electromagnetic interference testing is `bench-testing', performed on independent subsystems, and that this may suggest an interesting suspect point of weakness in the aircraft, namely the system interconnections. Recall one of the incidents he noted above: neither the electronics nor the well-shielded wiring itself, but the wiring connections seem to have been problematic. He reports incidents to specific aircraft (whose registration `tail numbers' are also given in the reports):
On a specific B737-300, a MCP (mode control panel) was doing weird stuff intermittently during several flights. I mean really weird: like letting both pitch and autothrottle fight each other to maintain speed. Nearly all boxes involved (MCP, FCC, several AFDS boxes) were changed before a clever mechanic found out that the windshield heat was not correctly grounded. This is located just a few inches from the MCP and is one of the big consumers on board. Tightening a few nuts solved an engineers nightmare.
On a specific B737-400, the FMC was doing weird things, mainly in cruise. Some pilots reported that after a request to the passengers to switch off electronic equipment, the problem was solved, others said it did not help anything even with every electronic gadget switched off in the cabin. Others reported nothing abnormal with CD's, PC's, Gameboys and more of that stuff trying to jam the system unsuccessfully. Troubleshooting was done and it was decided to replace another black box that was suspected. It was pulled out but, no spare was available. So the same black box was pushed in again. Problem solved, it never happened again!
Connections are a possible weak point. And difficult to duplicate if a problem exists. Can an imperfect connection make a tested system EMI susceptible or not?
(Ber97.3),
He emphasises, as do the RTCA and the other correspondents, that more research and systematic methods of testing are urgently to figure this situation out.
John Dimtroff is an electrical engineer on the Transport Standards Staff of the FAA Transport Aircraft Certification Directorate in Seattle. He is also a member of the Joint Airworthiness Authority/Federal Aviation Administration Electromagnetic Effects Harmonization Working Group. He has been a Federal Communications Commission investigator and inspector, a Boeing RF design engineer and a US Air Force Radar Specialist. Dimtroff reports some incidents first-hand:
...even the aircraft's own certified airborne equipment can play games on itself. [A few] years ago I was involved in identifying the source of [navigation instrument indicator] needle swings and voice modulations in the pilot's headset. [The culprit turned out to be a] certified airborne-authorized telephone broadcasting on a frequency which just happened to be commensurate with a piece of [navigation] equipment.
[Another case involved] the Flight Guidance Computer/Air Data Computer [which was] radiating unwanted signals, the 15th, 20th & 22nd harmonics of 6 & 8 MHz clock frequencies, [which are] right on the 120MHz & 132MHz VHF band! [But] each piece of [this] equipment met all the required RTCA DO-160 level testing [requirements].
...my experience with the FCC has taught me [to wonder] how many [PED] devices transmit with a clean, zero-spur signal, especially after being dropped, banged, klunked, fondled and sat upon. [In] my former FCC investigative days, [I saw] a number of devices (computers, stereos, TV's, etc., etc.) which purportedly met FCC Part 15 requirements as indicated by their label, [but] were either bogus marked, illegally imported or were just outside the manufacturing quality bell curve. [My personal view is] that every carry-on electronic device is suspect -- until it has been individually tested, which, of course, is impossible.
[My experience suggests to me that] it is nearly impossible to predict/replicate an EMI event on an aircraft when the event involves a portable carry-on device (PED). Location, orientation, power output, modulation, inconjunction with ALL the other PED's/electronics/electrics/avionics active at that time all play a role in the EMI event. And we must not exclude the terrestial based emitters (radars, etc). ...
(Dim97),
ARSR Summary of Reports, 1986 - June 1994
The following summary prepared by the ASRS was forwarded by Peter Mchugh of the FAA's Office of Aviation Safety, taken from Quick Response No. 271 dated November 30, 1994 (Mch97).
The following synoptic analysis of passenger electronic devices incidents was accomplished by the ASRS staff [at the request of the FAA]:
There were a total of 46 passenger electronic devices related incidents in the ASRS data base covering the period Jan 1, 86 thru June 30, 94. This number is in contrast to the 51,337 full form reports covering all types of incidents reported to the ASRS during the same period.
Passenger electronic devices incidents comprise .08 percent of the total full form reports in the ASRS database. Full form reports receive full analysis processing and include the reporter's narrative as part of the database record.
45 incidents involved passenger carrying operations. 33 of the incidents involved aircraft in the 60,000-300,000 lbs. weight classifications.
33 of the incidents referenced alleged aircraft systems interference from an onboard passenger electronic device. 10 of the incidents referenced alleged interference from an unknown onboard source. The remaining 3 reports make reference to FAA policy about the use of passenger electronic devices.
The breakdown of aircraft systems {reported} affected by passenger electronics devices interference included: nav equipment (37 incidents), aircraft communications equipment (9 incidents), radar altimeter equipment (1 incident) and fly-by-wire throttle controls (1 incident).
21 passenger electronic devices were specifically identified to be the sources of the aircraft systems interference. The reporters noted the interference ceased after the devices were turned off. The identified passenger electronic devices included:
Cell phones (4)
Laptop computers (4)
Portable AM/FM Radio Cassette Players (4)
Portable CD Players (3)
Electronic Games (3)
HF Radio (1)
Heart Monitor (1)
One report cited interference from 23 passengers using AM/FM radio cassette players.
One report cited unknown onboard interference causing ILS signal interference resulting in two missed approaches.
Two reports cited passenger use of cell phone as a cause of dual VOR nav failure.
None of the passenger electronic devices incidents had a critical impact on the safety of the flight.
Mchugh urges caution in interpreting the data. It has limited statistical significance because
reporting is voluntary and there is no statistical understanding of the total reporting population or any way of estimating what the actual number of events might be;
reporting is subjective and influenced by biases, including that reporters gain protection from FAA regulation-enforcement procedures and it is undoubtedly the case that some reports are generated mainly for that reason, and this may affect the quality of the report.
(Mch97).
(Indeed, many private pilots I know, including myself, carry ASRS reporting forms with us in our flight bags on every trip!) Accepting these caveats, however, the ASRS assembles many more anecdotes than other systems, and Mchugh notes that it is in many cases the "only game in town". And the personal, subjective nature of the reports can provide insight into the human factors issues resident in some events (Mch97).
Social and Administrative Pressures
The physical phenomenon of EMI interference seems to be relatively emphemeral. It is hard to determine if specific incidents are examples of the phenomenon, partly for the reasons Dimtroff remarks. In this respect, as McCormick points out, it distinguishes itself from other recurring problems such as icing, controlled flight into terrain (CFIT), and cargo-hold fire prevention and detection. These latter problems have clear, undisputed instances, and the question is what to do to prevent them. The question with EMI is what kind of a problem it is, and how to obtain clear instances.
There may be social and legislative pressures on participants which may color their response to this situation. Consider the following circumstance. US airlines may only allow use of PEDs if they are known to the airline not to cause interference (FAR 91.21). As we have noted, it is largely impractical to submit devices to stringent test, considering the number of devices on the market, and the varying condition of individual devices. Suppose a US airline reports and investigates an incident, suspected to be EMI. Ipso facto, that airline cannot therefore be deemed to have `determined ... non-interference', as required by FAR 91.21. Just the opposite, in fact -- they have suspected interference! Therefore, FAR 91.21 prohibits use of such a device on board that aircraft. A strict reading of the legislation thus leads directly from suspected-incident report to prohibition on that airline.
However, other airlines permitting use of such devices could legally continue to do so until they themselves were subject to an incident. A US airline fastidious about reporting and pursuing alleged EMI incidents could therefore find itself at a competitive disadvantage as it must prohibit PED use, and laptop and Gameboy users and cellphone owners with a penchant for not turning their devices off might well move their custom to rival airlines. Thus may airlines find themselves in a situation in which they must downplay reports or risk losing business, as a consequence of requirement FAR 91.21.
In Europe, many aircraft and crews are certified for the demanding automated approach procedures known as Category III (CAT III), in which the autopilot, following navigation signals, flies the aircraft on landing all the way to main gear touchdown on the runway. A reported incident of suspected EMI with PEDs on board such an airplane could seriously bring into question the aircraft's CAT III certification, since the aircraft electronic systems must be demonstrably highly reliable in order to exercise CAT III authority. An airline reporting such incidents officially could suffer the loss of CAT III certification on the incident airplane until the problem is discovered and rectified. Since EMI incidents, as we have remarked, appear to be very difficult to reproduce on the ground, one could imagine a scenario in which an airline reporting a suspected EMI incident is unable to trace the source, and therefore cannot exercise the CAT III capability on that airplane again. This would be a serious service limitation in the European environment. Again, this situation reveals a potential competitive disadvantage to airlines which take suspected EMI incident reports seriously.
If social pressures exist for airlines to downplay potential EMI incidents, one could also foresee the possibility of pressure from airline management on line pilots also to downplay observed avionics anomalies in service. It is easy to see that both of these social pressures could result in general underreporting and underinvestigating of suspected EMI incidents.
Finally, the pilot in command is directly responsible for the safety of those on board the aircraft. As André Berger has remarked, this responsibility includes avoiding all potential safety degradations, no matter how minimal. Thus, if EMI from a passenger PED is suspected, the only appropriate recourse, according to this legislative responsibility, is for the pilot to require the device immediately be turned off completely. This precludes any kind of correlation testing, benign or otherwise. However, recycling the device and trying to reobserve the interference is the most obvious simple test one can perform, and could be deemed benign in many circumstances. A fastidious interpretation of regulations concerning pilot responsibilities will, however, preclude it.
Since the current regulatory situation may thus unwittingly discourage reporting and investigation of suspected EMI incidents, there is a significant role for regulators to play in encouraging both reporting and investigation of such phenomena. I see five proactive ways for regulators to help:
in limiting the regulatory pressures towards underreporting and underinvestigating noted above;
in establishing reporting standards for such incidents;
in providing guidelines for, and allowing, if not encouraging, in-flight impromptu tests by the flight crew if certain sorts of benign influence from passenger electronics is suspected;
in providing guidelines for ground-based testing procedures in the wake of such incidents, possibly involving also the suspect PED equipment and its owner/user;
based on a classification of reports of the incidents, in clarifying which kinds of incidents would be considered to constitute a maintenance problem, and of which sort, and how those kinds would be considered to alter the certification status of the aircraft (particularly with regard to no-go and CAT III status).
The last of these measures, of course, could only be taken in a regulatory environment in which an absolute ban such as that in FAR 91.21 did not apply. The question of just what such an environment could look like is the topic of the first measure.
Conclusions
There are plentiful anecdotes of possible electromagnetic interference with aircraft systems. While the systems are subjected to thorough bench-tests under conditions of electromagnetic interference to demonstrate adherence to certification standards, there appears to be no systematic process for investigating and attempting to reproduce in-flight incidents, although the British Airways BASIS system, ASRS and EUCARE provide systematic logging of such reports, as one presumes do individual airlines for internal use.
Possible explanations of the lack of reproducibility of such incidents center on the environmental differences between the `bench tests' for certification, in which individual subsystems are tested independently, and the integrated aircraft environment. While entire aircraft are also subjected to some testing during certification, there may be individual differences between aircraft: if wiring connections are susceptible to interference, for example, then aircraft with a longer maintenance record may be more prone to interference incidents than brand-new ones.
While there is considerable disagreement amongst experts as to whether the phenomenon -- or phenomena -- are indeed cases of electromagnetic interference from passenger electronic devices, the call for more systematic testing appears to be unanimous. I have argued that some change in the regulatory environment will help. Nevertheless it appears clear that, whatever one's view on the reality of the phenomenon, an increasing number of reports on correlation will continue to appear at ASRS, BASIS and EUCARE.
Acknowledgements
My grateful thanks to those with whom I have engaged in correspondence on these issues, and who gave permission for me to quote them and summarise their arguments in this article: André Berger, Tony Broderick, Klaus Brunnstein, John Dimtroff, Jim Irving, Frank McCormick, Peter Mchugh, Peter Mellor, Werner Uhrig. May all our comments bear fruit. Thanks in particular to John Sheehan, Chairman of RTCA SC-177, for providing and giving us permission to reproduce the Executive Summary of RTCA DO-233.
Peter Ladki
Hijo, si todo el argumento de tis posts es el regurgitar tu odio a los pilotos,mejor firma como "Tonti", o, aun mejor, documéntate, escribe algo que aporte al debate, y luego firma como quieras.
Te puedo asegurar que insultando sólo te desacreditas tú.