lunes, 26 de abril de 2010

The Crash of Flight 592 – Part II

After the crash of Valujet flight 592, several airlines started to implement special requirements regarding the shipment of chemical oxygen generators. Some airlines even directly prohibited their shipment on the aircraft.

These requirements may be found in the “Operator Variations” in IATA's Dangerous Goods Regulations, which are not legally mandatory, but the airline will always have the final call on the acceptance of dangerous goods. Among the companies operating in Argentina, for instance, UPS and LAN regulate the packaging and marking of chemical oxygen generators (Variations 5X-06 and LA-05); British Airways, Lufthansa and Singapore Airlines prohibit the shipment of these devices (BA-05, LH-04, and SQ-06); and Continental Airlines only accepts them as COMAT, or Company Material (CO-05); COPA Airlines and United Airlines do not accept any oxidizing goods (CM-03 and UA-10). Other airlines, such as Iberia, Avianca, TAM, Aerolíneas Argentinas, Varig, Martinair, Air France and Air Europa do not have any special requirement, or Variation, regarding the acceptance of chemical oxygen generators, i.e., they accept them, unless a decision to the contrary is taken which is not stated in IATA's Regulations.

In order to implement the special requirements, it is obviously necessary that the airline staff be able to identify chemical oxygen generators when they are not declared as dangerous goods or if they are declared as such, but under a wrong classification for transport.

A very common mistake while handling chemical oxygen generators in aviation equipment maintenance facilities, is made when classifying the product for transport.

Mistakes in classification may include from declaring that the chemical oxygen generators are non-dangerous goods (or, more accurately, not declaring them as dangerous goods) to assigning the product a wrong risk class, shipping name and UN number.

However, even if a product is classified as a dangerous good, if the shipper is not familiarized with this issue, a wrong UN number and shipping name may be assigned, although the Risk Class may be the right one.

Most shippers usually simplify the issue and give a generic name for transport, without even trying to find a specific designation better describing the product.

If, for instance, we consider the material involved in the crash of flight 592, i.e., chemical oxygen generators which were not spent in the maintenance facilities, and taking into account that they contain a mixture of oxidizing solids (See The Crash of Flight 592, Part I), the material, without analyzing in depth the regulations on transport of dangerous goods, could be labeled as “Oxidizing solid, n.o.s. (sodium chlorate and potassium perchlorate, mixture),” UN 1479. However, packaging conditions would be very different if they are compared to those corresponding to the proper shipping name: “Chemical Oxygen Generators,” UN 3356.

First, it is strictly prohibited to transport products identified under UN 3356 in passenger aircraft. Some airlines even expressly prohibit them in all types of flights (see above). However, if the product has been classified under UN 1479, it may be shipped in passenger aircraft following a certain Packing Instruction which would not be applicable if any other UN Number were used.

This generic category (1) was the one most widely applied at the time of the accident. After the crash, global regulations changes were fostered by the relevant representatives of the United States, in order to include a United Nations number properly describing chemical oxygen generators and including their specific packing instructions. These changes contrast with the current Argentine laws on federal road transport(2), which do not contemplate UN 3356, Chemical Oxygen Generators. Transport by road of such devices should be made under UN 1479, Oxidizing Solid, N.O.S. (sodium chlorate and potassium perchlorate, mixture), i.e., the category used in the world 15 years ago.

Based on the description of the materials of the chemical oxygen generators and of the action mechanism (See The Crash of Flight 592, Part I), we could pose some questions regarding their classification for transport, for instance: If inside the device there is an explosive actuating device, why is a chemical oxygen generator not considered an Explosive?

In fact, this type of risk has priority with respect to the other types of risks, but pursuant to IATA's Regulations, the device must not be considered explosive if it contains explosive substances in an amount or in such a way that their inadvertent or accidental ignition or commencement during transport “does not cause any effect outside of the device or by projection, fire, smoke, heat or high noise.”

Please note that the sole effects external to the device are caused by the heat released by the reaction between the oxidizing materials and the combustible material.

Thus, the possibility of classifying the device as an explosive may be ruled out, given that the actual risk of chemical oxygen generators is that their content itself, and not only the small explosive load, may easily have a reaction. The explosive load is good only to trigger the reaction within the metallic shell, and does not cause any damage or effect on the external shell. Therefore, these chemical oxygen generators must be considered as oxidizing substances, and not as explosive materials.

Even in that case, if a more specific analysis of the classification of chemical oxygen generators is desired, there may be other alternatives which may be considered valid a priori:

• UN 1383, Pyrophoric alloys n.o.s. (iron powder, mixture)
• UN 3363, Dangerous goods in apparatus

The first one is wrong, because it merely describes a reactive component of the device.

The second one does not provide such an accurate description of goods as UN 3356, Chemical oxygen generators, the classification of which has been discussed in international organizations, such as the United Nations or the International Civil Aviation Organization (ICAO).

Even in that case, the acceptance staff at the airlines must be trained to recognize a chemical oxygen generator (or suspect its presence) at the time of accepting the shipment if they are misclassified or poorly packed.

The underlying problem does not lie on the airline cargo control staff, but on the shipper, which in the case of Company's materials is the airline itself or an airline contractor. The cargo control employee may be an individual very well-trained to perform his/her job, who may detect the slightest defect in the documentation or the package and who may even be able to discover dangerous goods not declared in the shipment. However, there is no reason for the cargo control employee to suspect about a wrong category: the cargo control employee will not open the package to check if the substance classified under UN 1383 is actually iron powder mixture. Least of all, there is no reason for the cargo control employee to suspect that a device contains such powder and may generate oxygen if accidentally activated.

When a shipment not declared as dangerous goods is delivered for transport, the airline cargo control employee may have a restrictive criterion and reject such shipment if there is any suspicion that flight safety may be at risk. The cargo control employee may do that. Even in the case of suspicion, the cargo control employee should require from shipper a proper confirmation of the content of the shipment (3).

But the issue is more complex when the load is declared as dangerous by the shipper. Who may tell the shipper that the product classification for transport is wrong and, therefore, that the product may not be transported? The airline cargo control employee? The Enforcement Authority? For most dangerous goods delivered for transport, assigning a risk class, a UN number and an appropriate shipping name entails a minimum chemistry and physics knowledge of which most members of the staff of the Enforcement Authorities and the logistics operators lack. In no means of transport, an airline, road transport company or shipping office is obliged to determine if the classification of a dangerous substance is right and to reject its loading if it is wrong.

As regards the Enforcement Authorities, they intervene in the classification of dangerous goods in specific cases, which are specifically mentioned in transport regulations. No regulation imposes upon an Enforcement Authority the obligation of stopping a shipment if it considers that it has been classified under a wrong category, nor entitles such authority to do that.

All transport regulations state that it is the shipper, i.e., the one delivering the goods for transport, the one who must know how to classify goods for transport. To that end, there is a Dangerous Goods Declaration which must be signed by the shipper, who becomes responsible for the category and the packaging conditions of the dangerous goods. Any intervention by the Enforcement Authority in the classification of products for transport, not expressly stated in the different international regulations, could give rise to abuses by the Authority.

In the case of the chemical oxygen generators involved in the DC9 crash, they were transported as COMAT, or Company Materials. This means that the shipper was Valujet, or someone acting in its name as shipper: Sabre Tech. Both of them were responsible for the tragedy as from the time the generators started to be handled. The problem did not lie on the checking of the cargo when shipping it for the flight, as the cargo control employee reviews the documentation and checks that it is in order and that it is consistent with the information stated in the packaging, without challenging the classification.

The cargo control employee knew that the products were chemical oxygen generators, but as he saw that they were declared only as “empty” (i.e., generators activated in the maintenance facilities by consuming the reaction inside, without any chance of a reactivation), the absence of any risk markings or labels on the packaging was not a surprise for him. They were declared “unloaded” or “empty” and, consequently, classified as non-dangerous goods by the shipper on land. That was indeed the worst classification that could be assigned due to handling mistakes in Sabre Tech's maintenance facilities. They mistook loaded generators with unloaded generators, and they delivered them for transport.

All airlines operating in our countries regularly replace the chemical oxygen generators in their aircraft. All of them may work with their own or third-party facilities, where the final disposal of generators may be handled.

It is often necessary to transport the removed generators by air; this must be done only on cargo flights, as transporting them in passenger flights has been forbidden in order to prevent another Valujet case.

Is it possible that a cargo control employee is very well-trained by the airline to detect undeclared dangerous goods, but that he/she accepts the entry of dangerous goods declared as such even if it is not properly classified?

There is no doubt that that may happen.

However, that classification must be assigned by airline staff, or else by staff of the companies retained for aircraft maintenance, supervised by the airline, as it is COMAT. Then, the question is another: May the airline or the third-party hired for aircraft maintenance make a mistake in the classification of the removed chemical oxygen generators by assigning them a wrong category which allows them to be transported in passenger flights?

If the airline's (or contractor's) staff assigned to aircraft maintenance is not duly trained regarding the risks of chemical oxygen generators and their transport category, then the answer is, once again, yes.

In view of the events, that is too much responsibility for airlines, so they seek to avoid any accident, as one single accident may cause them to disappear as a Company. Furthermore, users trust the airline security thinking more about the aircraft conditions, the pilots' skills or the capacity of cargo control employees to detect undeclared, poorly packaged or wrongly documented dangerous goods. All those factors may be found in the Airport-Air zone. However, what happens on the Land zone and, more specifically, in the aircraft maintenance facilities is essential and is hidden to the users' eyes.

Management of Company Materials, or COMAT, such as chemical oxygen generators admits no errors. Unfortunately, air transport had to learn that after experiencing the crash of flight 592.



(1) UN 1479, Oxidizing Solid, n.o.s. (…), where n.o.s. means Not otherwise specified. The generic designation for transport arises from this category.

(2) In the Argentine Republic, Resolution No. 195/97 of the Secretary of Transport, Technical Standards for Road Transport of Dangerous Goods.

(3) Dangerous Goods Regulations of the International Association of Air Transport (IATA)



Translated by Camila Rufino, Accredited Translator

miércoles, 21 de abril de 2010

La Caída del Vuelo 592 Parte III

Durante la preparación de las mercancías peligrosas para el transporte, cualquier error en la clasificación de la misma puede conducir a errores en el embalado, eligiendo los materiales de embalaje incorrectos o colocando dentro cantidades no permitidas del producto.

Aún si se asume que la clasificación es correcta, seguiría habiendo posibilidad de error en el embalado.

Cuando el Panel Nacional de Seguridad en el Transporte de los Estados Unidos (NTSB) investigó el accidente del DC 9-32 de la línea Valujet, ocurrido el 11 de mayo de 1996, determinó como causa probable a la activación de generadores químicos de oxígeno, los cuales no se hallaban adecuadamente preparados para el transporte (por ejemplo, faltaban tapas o precintos de seguridad que impiden el accionamiento involuntario de los dispositivos) (1).

Luego del accidente, las autoridades competentes de Estados Unidos impulsaron una serie de medidas tendientes a incrementar la seguridad con relación a los tipos de vuelos permitidos y a los embalajes a utilizar, no solo para el transporte de generadores químicos de oxigeno sino también para el transporte de sustancias oxidantes, y especialmente del oxígeno medicinal, que suele ser transportado con frecuencia dada su importancia para la vida de muchas personas.

Primero prohibieron el transporte de generadores nuevos en aviones de pasajeros, en tanto que los generadores descartados (usados o sin usar) fueron prohibidos tanto en aviones de pasajeros como en aviones de carga. Luego regularon el transporte en aviones de carga mediante la emisión de aprobaciones por la Administración de Investigación y Programas Especiales (RSPA), hoy Administración de Seguridad en Conductos y Materiales Peligrosos (Pipeline and Hazardous Materials Safety Administration – PHMSA)(2).

A su vez, en 1997 también estaban emergiendo nuevas disposiciones referentes al transporte de cilindros conteniendo oxígeno comprimido, siempre a raíz del mencionado accidente.

Posteriormente, en 1999 comenzó a ser regulada la cantidad de cilindros que contienen oxígeno medicinal en la cabina de los aviones de pasajeros (49 CFR 175.10 (b)), y también la cantidad máxima de cilindros a transportar como carga en compartimientos que no cuenten con sistemas de lucha contra incendios (49 CFR 175.85 (h). A partir de ese momento, todos los cilindros de oxígeno comprimido debían comenzar a ser colocados en embalajes exteriores que cumplan con criterios de comportamiento de instrucciones de embalajes especiales (49 CFR 172.102).

Todos estos requerimientos fueron luego reflejados en la Reglamentación de Mercancías Peligrosas de IATA a través de la Variación de Estado USG-15 (3).

En 2007, la PHMSA introdujo una nueva regulación referente a las características de embalajes para los generadores químicos de oxígeno, oxígeno comprimido y otros gases oxidantes (6). La nueva norma impuso que los embalajes destinados a contener estos materiales deben cumplir con dos requisitos fundamentales:

• Resistencia a la penetración de llama igual a la de los tabiques de los compartimientos de carga, es decir unos 927 ºC por 5 minutos (5).

• Resistencia térmica debido a la exposición indirecta al calor generado durante un incendio. Esta protección ha sido determinada para que el actuador de un generador químico de oxígeno no sea activado por el calor de un incendio en la bodega, y para evitar o disminuir cualquier aumento de presión en el interior de los cilindros que pudiera ocasionar la liberación del oxígeno en caso de activación del aparato. La temperatura estimada de la bodega de un avión durante un incendio combatido con gas halón es de 204 ºC. Los generadores de oxígeno no deben ser activados cuando se encuentran sometidos a esta temperatura durante 3 horas. Este lapso de tiempo surge de estimar un tiempo máximo de aterrizaje forzoso en el primer lugar posible, considerando que el avión se encuentre sobrevolando el Océano Pacífico hacia el sur (6).

La reglamentación lanzada en 2007 recibió numerosas quejas de parte de fabricantes de embalajes, expedidores y líneas aéreas. Varias organizaciones presentaron apelaciones para postergar la puesta en vigencia de esta norma, basándose principalmente en los costos y disponibilidad en el mercado de los embalajes exteriores que cumplan con las dos características mencionadas.

Como resultado de estos reclamos, la PHMSA y la Administración Federal de Aviación (FAA) decidieron monitorear la disponibilidad en el mercado de los embalajes requeridos y prorrogar la implementación de la norma hasta el 1 de octubre de 2009, fecha en la cual finalmente comenzaron a regir las nuevas disposiciones de comportamiento de estos embalajes, a pesar de que siguieron sonando algunas voces de protesta (6).

Algunas fueron escuchadas, por ejemplo el reclamo presentado por la empresa Satair USA, para modificar las limitaciones de peso de los embalajes que contienen generadores químicos de oxígeno: teniendo en cuenta que los nuevos embalajes implican mayores pesos por tener que utilizar embalajes más robustos que cumplan con las características de resistencia requeridas, era necesario cambiar el peso máximo permitido de 25 kg brutos a 25 kg netos en aviones de carga (permaneciendo prohibido su transporte en aviones de pasajeros). Esto es, pasar de un peso total del embalaje, a un peso que correspondiente solamente a la mercancía peligrosa, sin tener en cuenta al embalaje exterior. Y efectivamente, los nuevos pesos admitidos para aviones de carga entraron en vigencia en USA el 1 de octubre de 2009 y a su vez fueron admitidos por la OACI para su inclusión en la próxima enmienda de las Instrucciones Técnicas (7). Como es común , este cambio también ha sido reflejado en la Reglamentación IATA a través de la Variación de Estado correspondiente a USA.
.
Como puede observarse, los nuevos requerimientos de embalajes han sido implementados en los Estados Unidos y para los Estados Unidos. Pero también han sido presentados en el seno de la Organización Internacional de Aviación Civil (sus siglas ICAO en inglés) durante la reunión del Grupo de Expertos en Mercancías Peligrosas del año 2007 (8). En aquel momento, la delegación norteamericana presentó sus modificaciones locales y adelantó la inclusión de una nueva Variación de Estado en las Instrucciones Técnicas de la OACI, de modo que incluya los nuevos requerimientos técnicos de embalajes para generadores químicos de oxígeno y cilindros con este gas.

La implementación del uso de embalajes que presenten características estandarizadas de resistencia térmica y resistencia a la penetración de llamas es inminente, y esto seguramente va a significar una barrera comercial para muchos países en vías de desarrollo, que no se encuentren preparados para estos cambios. Las líneas aéreas son las primeras en tener que cumplir los nuevos requisitos, ya que usualmente los generadores químicos de oxígeno son Materiales de la Compañía (COMAT, sus siglas en inglés).

Los operadores aéreos han tenido que adaptarse a lo largo de estos últimos años a las medidas de seguridad en la gestión de estos materiales: tuvieron que comenzar a utilizar solamente aviones de carga (lo que suele implicar menores frecuencias de vuelos y mayores costos); tuvieron que realizar solamente los envíos de los materiales nuevos, debiendo gestionar la disposición de los generadores usados o vencidos y siendo estos residuos peligrosos; y ahora comenzaron a adoptar los nuevos embalajes requeridos por la reglamentación norteamericana (6), más caros y difíciles de conseguir.

Lo deben cumplir las líneas aéreas de los demás países para los vuelos desde, hacia o a través de los Estados Unidos. No sería raro que en próximas ediciones de las Instrucciones Técnicas de ICAO y del Reglamento de Mercancías Peligrosas de IATA estos requerimientos de embalaje figuren en forma general para vuelos que involucren a todos los demás países, no solamente Estados Unidos.

Para muchas líneas aéreas, adaptarse a estos nuevos requerimientos de embalajes seguramente costarán sangre, como casi todas las políticas necesarias para mejorar la seguridad en el transporte, y esto podría conducir a que algunas líneas aéreas que actualmente aceptan generadores químicos de oxígeno comiencen a rechazarlos, como ya lo están implementando algunos otros operadores (ver La Caída del Vuelo 592 Parte 2).

Un posible resultado de todas estas medidas: mayor seguridad en el transporte pero menores posibilidades de mover los generadores de oxígeno, y mucho menos a valores razonables de mercado, lo cual también es importante.



(1) National Transportation Safety Board (NTSB), 1997. Aircraft Accident Report, In-Flight Fire and Impact with Terrain, ValuJet Airlines, Flight 592, DC-9-32, N904VJ, Everglades, Near Miami, Florida, May 11, 1996, Reporte No. NTSB/AAR-97/06(PB97-910406), August 1997.

(2) 61 CFR 24618 y 61 CFR 68952, regulaciones de Estados Unidos surgidas el mismo año del accidente (1996).

(3) Dangerous Goods Regulations – International Air Transprot Asociation, 51 Ed.

(4) Regulación RSPA-04-17664 (HM-224B)

(5) 14 CFR Parte 25, Parte III del Apéndice F, Párrafos (a) (3) y (f) (5)

(6) Docket Nº PHMSA-2009-0238 (HM-224G). Federal Register , Vol 74 Nº 198. USA.

(7) 22nd MEETING OF THE DANGEROUS GOODS PANEL (DGP) (2009) - ICAO

8) DGP/22-WP/99 - QUANTITY LIMITATION FOR PACKAGES OF CHEMICAL OXYGEN GENERATORS TRANSPORTED ABOARD CARGO-ONLY AIRCRAFT