Jason Dickstein, president of the Washington Aviation Group, advises that proper training is crucial to avoid overlooking potentially serious safety issues.

Dangerous goods (which are also known as hazardous materials – or hazmat – in the US) can be an important safety concern for the aviation industry.

There are many hazmats in aircraft and aircraft parts, and the hazards are not always obvious to the untrained eye, so it is easy to overlook a serious safety problem unless you have the right training.

Hazardous materials are a serious concern for the world’s aviation authorities because they have caused aircraft accidents. The best known example was the 1996 ValuJet accident caused by chemical oxygen generators but there are many other less well known examples, including incidents involving lithium batteries. As a consequence of this history, regulators tend to be unforgiving when it comes to hazmat violations.

Over the past 20 years, the US has made efforts to amend its hazardous materials regulations so that they are closer to the international standards.

At the same time, the remainder of the world has increased its expectations with regards to safe shipping of these articles. This has resulted in international compliance becoming much easier, and today it is possible to purchase a book (the IATA Dangerous Goods Regulations) that explains both the international standards and also the national variations that are peculiar to individual countries.

Dangerous goods are divided into nine classes. These classes are standard around the world, and there are aircraft parts in practically every class:

Class 1: Explosives

Many people are surprised to learn that small explosive squibs are used to activate emergency systems, such as blowing the seal on a fire suppression system. These small squibs may not look like much, but they are regulated as class 1 explosives that need special handling under both hazmat regulations and ATF regulations.

Class 2: Compressed gases

Compressed gases found in aircraft can include oxygen bottles, nitrogen bottles and carbon dioxide cylinders. Apart from any other hazards, the compression itself is a hazard. When the non-flammable gas has no subsidiary hazards then reducing the compression below regulated levels can be an effective way to make the gas non-hazardous (make sure you don’t violate the Clean Air Act), but note that gasses with subsidiary hazards (like oxygen, which is also a class 5 hazard) may continue to be regulated even if the pressure is below regulated thresholds.

Class 3: Flammable liquids

Class three can range from alcohols to paints. Aviation fuels tend to be regulated as class three materials. Things with fuel in them are typically regulated as well. For example, when fuel is regulated under class 3, the fuel system components with residue in them are regulated as ‘dangerous goods in articles’ under class 9.

Class 4: Flammable solids

Matches are a common example of a flammable solid. Most flammable solids are too volatile to be used in aircraft parts.

Class 5: Oxidizers

Oxygen is the most common class five material in an aircraft, and this includes chemical oxygen generators. When a passenger service unit (PSU) is removed from an aircraft, it is important to remove the chemical oxygen generators from the PSU before the PSU is shipped, so the chemical oxygen generators can be properly prepared for transportation.

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Class 6: Toxics

This can include older formulations of chemical films, bearing greases and other chemicals. It can also include metal dusts generated in certain production environments. Some chemical manufacturers appear to have actively tried to replace their toxic formulations with non-toxic formulations.

Class 7: Radioactives

Radioactivity has to do with the emission of particles from certain isotopes. Calculating whether something is subject to the radioactivity rules can be complicated because different isotopes have different activity levels at which they are regulated. So, if you have a fluorescent emergency sign that fluoresces because of a radioactive isotope, you will need to identify both the isotope and also the amount of radioactivity (which may be measured in becquerels or curies).

Modern aviation articles that have radioactive isotopes in them are often designed around the rules, so that their total activity level falls below the regulated thresholds. When you measure the activity level of a modern aircraft ‘radioactive’, don’t be surprised if it falls below the regulated thresholds found in the regulations.

But this has not always been the case and older radioactives may be more likely to be regulated. This includes depleted uranium counterweights found in aircraft like 747s built before 1981 and the L-1011.

Class 8: Corrosives

While you may have class eight cleaning supplies, the class eight materials that are most likely to be shipped by most aviation companies reading this article are batteries. Class eight includes most batteries other than lithium batteries (class 9) and sodium batteries (class 4 but typically not found in aircraft).

Class 9: Miscellaneous dangerous goods

Class nine is where most aircraft parts tend to fall. This class includes things like dangerous goods in articles, which is a catch-all for articles containing hazmat. This can be articles such as fuel system components, which may have a residue of fuel in them, or articles that normally include hazmat as part of their design, such as certain capacitors that contain a flammable electrolyte solution. Other common examples of class nine hazards found on aircraft include engines, self-inflating life-saving equipment, first aid kits and avionics with back-up batteries.

Do you get periodic training?

Training is at the root of the international hazmat enforcement regime. Under US law, anyone who makes any decision affecting the safe transport of hazardous materials is required to be hazmat-trained. This means shipping personnel must be trained and certified, but it also means that supervisory personnel and support personnel must also be trained and certified.

If one person places an aircraft part in a box, and then the shipping department seals and ships the package, then the person who placed the aircraft part in the box as well as the shipper are both subject to the training requirements.

One Department of Transportation interpretation memo explains that even administrative assistants must be trained if they (for example) merely participate in the creation of hazmat shipping papers (like merely typing the information into a form based on handwritten notes created by someone else).

The international standards for periodic training require recurrent training every two years. US law applies the two year standard to air carrier personnel (and those performing transport related functions for air carriers) and applies a more relaxed three year recurrent training standard to non-air carrier personnel. For those shipping internationally from US manufacturing, repair or distribution businesses, this probably means that they must get training every two years to meet the standards of the nations to which they ship, even though US law may only require recurrent training every three years.

Training is available

We offer aviation-specific hazmat training twice a year – our next class, a live webinar, will take place on 17-18 April and will allow you to study from the comfort of your own workplace.

More information on hazmat training is available online at DangerousGoodsTraining.net.

This feature was first published in MRO Management – March 2024. To read the magazine in full, click here.