Operators' Own Property (COMAT) & Dangerous Goods in Air Mail
Key Takeaways
- Company Material (COMAT) is dangerous goods carried on an operator's own aircraft for its own purposes, and it remains fully subject to the DGR unless a specific relief in Subsection 2.4 applies.
- A handful of items required on board for airworthiness, operating reasons, passenger comfort, or medical care are not subject to the Regulations at all — aircraft batteries, first-aid kits, and catering supplies in use are the classic examples.
- Dangerous goods in air mail are controlled through the Universal Postal Union in cooperation with ICAO, and postal administrations may only accept the narrow list of items the DGR permits in mail.
- Never treat a COMAT or mail exception as a general exemption: the relief attaches to the specific item, quantity, and purpose, and everything outside it is a full dangerous goods shipment.
Operators' Own Property (COMAT) & Dangerous Goods in Air Mail
Section 2 of the IATA DGR does not stop at forbidden goods, hidden goods, passenger baggage, and variations. Two further limitation topics complete it, and both appear regularly on acceptance and processing assessments precisely because they are the ones candidates skim: dangerous goods carried as the operator's own property (COMAT) under DGR 2.4, and dangerous goods in air mail under DGR 2.5.
1. Company Material (COMAT)
COMAT — company material — is any property of the operator carried on that operator's own aircraft. An airline routinely moves its own spare parts, wheels and brakes, tooling, cabin equipment, chemicals for line maintenance, and aircraft batteries between its own stations. When those items are dangerous goods, they do not stop being dangerous goods simply because the airline owns them.
The Default Rule
COMAT dangerous goods are subject to the full requirements of the Regulations — classification, packing, marking, labelling, documentation, acceptance, loading and NOTOC — in exactly the same way as a third-party shipper's consignment, unless a specific provision in Subsection 2.4 relieves them.
This is the single most misunderstood point in the topic. "It's COMAT" is not an answer to an acceptance question. The correct question is always: which specific provision relieves this item, and does the item actually meet its conditions?
What Genuinely Falls Outside the Regulations
A short, closed list of items required on board is not subject to the Regulations at all, because they are part of the aircraft or its operation rather than cargo:
| Category | Typical Items | Why It Is Outside |
|---|---|---|
| Airworthiness and operating requirements | Aircraft batteries installed in the aircraft, fire extinguishers, oxygen bottles and chemical oxygen generators forming part of the aircraft, hydraulic fluid and de-icing fluid in aircraft systems | Required to be on board for the aircraft to operate safely |
| Passenger and crew comfort | Aerosols and alcoholic beverages carried in the catering and duty-free service, dry ice used for catering | In use for the service of the flight |
| Medical care of a patient | Medical oxygen, gas cylinders and equipment for a patient in flight, where the operator has approved the carriage | Carried for immediate medical need |
| Veterinary aid or humane destruction of an animal | Approved veterinary items | Immediate animal welfare need |
The moment any of those items is packed and tendered as cargo rather than being in use on the flight, the relief evaporates. A fire extinguisher installed in the cabin is outside the Regulations; the same extinguisher boxed and flown to another station is Division 2.2 cargo requiring a full declaration.
The COMAT Trap on Acceptance
Hidden dangerous goods risk is unusually high in COMAT because the tendering party is a colleague rather than a customer, and the paperwork culture is looser. Aircraft on Ground (AOG) shipments are the worst offender: a single AOG box can contain a chemical oxygen generator (Division 5.1), an escape slide inflation reservoir (Division 2.2), a fuel control unit with residual fuel (Class 3), and a lithium battery pack. Acceptance staff must apply exactly the same checklist to COMAT as to commercial cargo.
2. Dangerous Goods in Air Mail
Postal traffic is governed by the acts of the Universal Postal Union (UPU), which develops its rules in cooperation with ICAO. The DGR reflects the outcome in Subsection 2.5.
The Governing Principle
Dangerous goods must not be carried in mail except for the narrow categories the Regulations expressly permit, and even then only where the designated postal operator has been approved by the national authority to accept them. The mail channel is the most restrictive route in the whole system — far tighter than cargo — because there is no acceptance check, no shipper's declaration, no NOTOC entry, and no way for the operator to inspect the contents.
What Is Typically Permitted in Mail
The permitted list is short and is expressed by reference to specific provisions rather than by hazard class. In broad terms it covers:
- Patient specimens and Category B biological substances (UN 3373) prepared to the applicable packing instruction;
- Radioactive material in excepted packages, where the postal administration is approved to accept it;
- Lithium batteries contained in equipment, in very small numbers, prepared under the applicable Section II conditions and subject to national postal acceptance;
- Dangerous goods in excepted quantities, where permitted.
Everything else — aerosols, perfumes, nail varnish, lighters, power banks, standalone lithium batteries, and any fully regulated consignment — is forbidden in mail.
Why the Standalone Battery Point Matters
Because Section II was removed from Packing Instructions 965 and 968 in 2022, standalone lithium ion and lithium metal cells and batteries are fully regulated Cargo Aircraft Only shipments requiring a Shipper's Declaration. There is therefore no route by which a standalone lithium battery or power bank may travel in air mail. Undeclared power banks in the post remain one of the highest-frequency causes of dangerous goods occurrences reported by postal operators.
3. Working Rule for Both Topics
For COMAT and for mail alike, apply the same three-step test at acceptance:
- Identify the item and classify it as though it were ordinary cargo.
- Find the specific provision in Subsection 2.4 or 2.5 that is claimed to relieve it, and read the conditions.
- If any condition is unmet — or if no provision is cited — treat it as a fully regulated consignment and require the complete documentation set.
An airline tenders a boxed cabin fire extinguisher for carriage on its own aircraft from its main base to an outstation, described on the paperwork simply as 'COMAT'. How must the acceptance agent treat it?
Which of the following may legitimately be carried in air mail?
Which body develops the rules governing dangerous goods in air mail, and in cooperation with whom?