An AOG order is agreed, the part is serviceable, the paperwork is clean — and the shipment still sits at the forwarder for days. Often the reason is not price or documents but classification: the component contains, or is itself, a dangerous good. Oxygen generators, gas bottles, squibs, batteries and fuel-wetted parts all fall under hazardous materials rules when they move by air, and the rules decide which aircraft may carry them.

For buyers in Africa and South and Southeast Asia, on routes where cargo moves mainly in the belly of passenger flights, this matters twice: a part that is forbidden on passenger aircraft has to find a freighter, and a part that was declared wrongly can be refused at acceptance. This guide explains what to ask before you pay, so the aircraft parts dangerous goods question is answered at the quote stage rather than at the cargo terminal.

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Which aircraft parts count as dangerous goods

A short list from Jason Dickstein of Washington Aviation Group (Aviation Business News, 17 May 2024) shows how wide the net is. His examples include passenger service units with chemical oxygen generators (Class 5), emergency systems that use small explosive squibs (Class 1), oxygen, nitrogen and CO2 cylinders (Class 2), fuel system components that may retain fuel residue, self-luminous emergency signs that may contain radioactive isotopes (Class 7), depleted uranium counterweights on older 747s and L-1011s, most non-lithium batteries (Class 8), and engines, life-saving equipment, first aid kits and avionics with backup batteries (Class 9).

In other words, a large share of what an operator buys for an ageing fleet — cabin, emergency and engine items especially — can trigger the rules. The FAA notes the same from the repair side: many certificated repair stations ship dangerous goods, “such as aircraft parts, equipment containing lithium batteries, flammable paints and solvents”, and all aircraft parts “must be sufficiently cleaned of residue and purged of vapors to remove any potential hazard” before shipment.

Part type	Why it is regulated	Ask the supplier
PSU / oxygen generator	Chemical oxygen generator (Class 5)	Is the generator fitted? Can it ship on a passenger flight? (No.)
Oxygen, nitrogen, CO2 bottles	Pressurised gas (Class 2)	Charged or empty? Which UN number is declared?
Emergency systems with squibs	Explosive device (Class 1)	Is the cartridge installed or shipped separately?
Fuel system components	Fuel residue	Drained and purged? Is there a statement?
Avionics, ELTs, kits with batteries	Batteries (Class 8 / 9)	Battery type, and is it installed in the unit?

Oxygen generators: the classic passenger-aircraft ban

The strictest case is the chemical oxygen generator. Under US hazardous materials rules, 49 CFR 173.168 states plainly: “A chemical oxygen generator is forbidden for transportation on board a passenger-carrying aircraft.” The same section sets packaging (rigid outer packaging at Packing Group I or II performance, or an ATA Specification 300 Category I container) and requires protection against accidental actuation — for example, two pins, or one pin plus a retaining ring, on mechanically actuated devices.

The rule has a history every buyer should know. The US regulator moved on oxygen generators after the crash of a passenger aircraft on 11 May 1996 that killed 110 people; in December 1996 it proposed prohibiting their carriage on passenger aircraft (Federal Register, 30 December 1996). Because the ban is absolute, a PSU quoted as “ready to ship” should always come with a clear answer on whether the generator is fitted and how it is protected.

Batteries: installed versus loose

Batteries are the second big trap, and the difference between “installed” and “loose” decides the route. According to PHMSA, the US interim final rule of 2019 prohibits lithium ion cells and batteries shipped under UN3480 — that is, not packed with or contained in equipment — as cargo on passenger aircraft, and requires them to be shipped at not more than 30 percent state of charge on cargo-only aircraft. Batteries packed with or contained in equipment (UN3481) remain authorised on passenger aircraft.

For a buyer, the practical question is simple: will the battery travel inside the unit, or will the seller remove it and ship it as a spare? A spare lithium ion battery shipped on its own is a different shipment from the same battery installed in the unit, and the airline’s own acceptance policy may be stricter than the regulation.

Who is responsible for the declaration

The shipper. IATA’s training guidance is direct: “The shipper is required to correctly declare according to the classification found in the IATA DGR”, including identifying the shipment as dangerous goods and filling in the Shipper’s Declaration for Dangerous Goods correctly. Training is part of that obligation: IATA requires recurrent training “every 24 months”, and under 49 CFR 172.704 a US hazmat employee must be retrained “at least once every three years”, with initial training completed within 90 days of starting the job.

This is why the seller’s answer “our forwarder will handle it” is not enough. The forwarder packs and books; the classification has to come from someone who knows what is inside the part. When the seller is a broker without trained staff, agree in writing who prepares the declaration and who pays if the consignment is rejected.

What to put in the RFQ and the purchase order

Add three lines to every request for a component that could fall under the rules:

• Is the part shipped as dangerous goods? If yes, the UN number and class as they will appear on the declaration.
• Can it travel on a passenger aircraft, or cargo aircraft only? This decides the routing and the lead time.
• Who prepares the Shipper’s Declaration, and does that person hold current dangerous goods training?

Then plan the route around the answer. If the part is cargo-aircraft-only, the shortest passenger routing is off the table and the hub choice changes — see our guide to routing aircraft parts through Nairobi and Addis Ababa. Import paperwork does not disappear either; the customs file described in importing aircraft parts into Africa still applies on top of the dangerous goods declaration.

Common mistakes that cost days

Typical errors to rule out before dispatch: a generator or cartridge left installed without anyone saying so; a fuel component shipped without being drained and purged; a lithium ion battery removed and shipped loose on a passenger routing; and a declaration signed by someone without current training. Each of them can stop a shipment at acceptance, and none of them is visible from the part number alone.

When you source through live RFQs on Aviatrading, state the dangerous goods question in the request itself so suppliers quote a realistic route and lead time from the start. Sellers can register on Aviatrading to answer requests directly, and new requests are also shared in our Telegram channel.

This article summarises published rules and guidance for buyers. It is not a substitute for a trained dangerous goods specialist, and the carrier’s own acceptance policy always applies.