The Crash of Flight 592 - Part III

While preparing dangerous goods for transportation, any mistake in the classification of such goods may cause mistakes in the packaging, by selecting inappropriate packaging materials or transporting in them quantities of the product which are not allowed.

Still, even assuming that the classification is correct, there could be some mistakes in the packaging.

When the U.S. National Transportation Safety Board (NTSB) investigated the crash of Valujet DC 9-32, which occurred on May 11, 1996, it determined that the probable cause had been the activation of chemical oxygen generators, which had not been duly prepared for transportation (for instance, safety caps or seals that prevent the involuntary activation of the devices were missing) (1).

After the accident, the relevant U.S. authorities pursued a series of measures aimed at increasing safety with respect to the types of flights allowed and the packaging to be used for transporting not only chemical oxygen generators, but also oxidizing substances, in particular, medical oxygen, which is transported frequently given its importance for the life of many people.

First, transporting new generators in passenger aircraft was forbidden, while discarded generators (either used or unused) were forbidden both in passenger and cargo aircraft. Later, transport in cargo aircraft was regulated through approvals given by the Research and Special Programs Administration (RSPA), now called Pipeline and Hazardous Materials Safety Administration (PHMSA)(2).

In turn, in 1997 new provisions were issued in connection with the transport of cylinders containing compressed oxygen, always as a result of the accident mentioned above.

Then, in 1999, the number of cylinders which contained medical oxygen that could be transported in the cabin of passenger aircraft started to be regulated (49 CFR 175.10 (b)), as well as the maximum number of cylinders to be transported as cargo in compartments without fire suppression systems (49 CFR 175.85 (h)). As from that moment, all compressed oxygen cylinders had to be transported in external packages meeting the behavior criteria stated on special package provisions (49 CFR 172.102).

All these requirements were then reflected in IATA's Dangerous Goods Regulations through State Variation USG-15 (3).

In 2007, PHMSA introduced a new regulation related to the characteristics of packages for chemical oxygen generators, compressed oxygen and other oxidizing gases (6). The new rule provided that packages for those materials must comply with two main requirements:

• Resistance to penetration by flame equal to that of the walls of the cargo compartment, i.e., about 927 ºC during 5 minutes (5).

• Thermal resistance due to the indirect exposure to heat generated during a fire. This protection has been required so that the actuating device of a chemical oxygen generator does not activate by the heat of a fire in the deck, and to avoid or reduce any pressure increase within the cylinders, which may cause the oxygen release upon activation of the device. The estimated temperature in the deck of an aircraft during a fire fought with halon gas is 204 ºC. Oxygen generators must not be activated if they have been under that temperature for 3 hours. This period results from calculating a maximum time for a forced landing in the first possible place, considering that the airplane is flying on the Pacific Ocean southwards (6).

Several complaints were received regarding the 2007 regulations from package manufacturers, shippers and airlines. Several organizations filed appeals to put off the coming into force of this rule, based mainly on the costs and availability in the market of the external packages with those two characteristics mentioned above.

As a result of those claims, PHMSA and the Federal Aviation Administration (FAA) decided to control if the required packages were available in the market and to extend the implementation of the rule until October 1, 2009, on which date the new regulations on behavior of those packages became effective, though there were still some protesting voices (6).

Some of them were heard; for instance, the claim filed by the company Satair USA, which requested the modification of the weight restrictions on packages containing chemical oxygen generators: considering that the new packages entailed heavier weights because heavier packaging must be used to meet the resistance characteristics required, it was necessary to change the maximum allowed weight from 25kg gross to 25kg net in cargo aircraft (however, transport was still forbidden in passenger aircraft). This means passing from the total weight of a package to the weight only of the dangerous goods, without taking the external package into account. And actually, the new weights allowed for cargo aircraft became effective in the USA on October 1, 2009 and, in turn, were admitted by ICAO for them to be included in the next amendment of the Technical Instructions (7). As usual, this change has also been reflected in IATA's Regulations through the State Variation for the US.

As it may be observed, the new package requirements have been implemented in and for the United States. However, they have also been presented within the International Civil Aviation Organization (ICAO) during the 2007 meeting of the Group of Experts on Dangerous Goods (8). At that time, the American delegation submitted their local amendments and advanced that they were to include a new State Variation in ICAO's Technical Instructions, so that it contained the new technical requirements for packages for chemical oxygen generators and cylinders containing that gas.

The implementation of the use of packages with the standardized characteristics of thermal resistance and resistance to penetration by flame is imminent and this will certainly be an obstacle for trade for many developing countries which are not prepared for these changes. Airlines are the first that have to comply with the new requirements, as chemical oxygen generators are usually Company Materials (COMAT).

In the last few years, air operators had to adapt to security measures in the handling of these materials: they had to start using only cargo aircraft (which usually entails less flight frequencies and higher costs); they could only send new materials and had to perform other proceedings to dispose of used or expired generators, which are dangerous waste; and now they have started to adopt the new packages required under the American regulations (6), which are more expensive and more difficult to get.

Airlines from other countries have to meet these requirements when flying to or from or through the United States. It would not be a surprise if future editions of ICAO's Technical Instructions and of IATA's Dangerous Goods Regulations provide these package requirements in general, for flights involving all other countries, not only the United States.

For many airlines, adapting to these new package requirements will certainly be extremely difficult, as it is adapting to almost all policies which are necessary to improve transportation safety. This could cause that some airlines which currently accept chemical oxygen generators start to reject them, as other operators are already doing (see The Crash of Flight 592 - Part 2).

A possible result of all these measures could be: increased transportation safety, but less possibilities of moving oxygen generators, least of all at reasonable market values, which is also important.



(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, Report No. NTSB/AAR-97/06(PB97-910406), August 1997.

(2) 61 CFR 24618 and 61 CFR 68952, US regulations issued the same year of the crash (1996).

(3) Dangerous Goods Regulations – International Air Transport Association, 51 Ed.

(4) Regulation RSPA-04-17664 (HM-224B).

(5) 14 CFR, Part 25, Part III of Appendix F, paragraphs (a) (3) and (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


Translated by Camila Rufino, Accredited Translator