Compatibility Check
IATA DGR 67th Ed. Section 9.3 — which dangerous goods classes can be loaded together on the same aircraft. Based on the segregation matrix (Table 9.3.A), forbidden combinations, overpack co-packing rules, and practical loading guidance.
Key Principle: Dangerous goods that are incompatible must never be loaded on the same aircraft, placed in the same overpack, or packed in the same outer packaging. The pilot-in-command (NOTOC) must be informed of all DG aboard.
Fundamental Rules
Same Aircraft Rule
Incompatible dangerous goods must not be loaded on the same aircraft. The segregation requirements apply regardless of whether goods are in the cargo hold, on the main deck, or in a ULD.
Overpack Restrictions
Dangerous goods of different classes may only be placed in the same overpack if they are compatible according to Table 9.3.A. If any pair within the overpack is incompatible, the entire overpack must be rejected.
All-Packed-in-One Outer Packaging
When different dangerous goods are packed together in a single outer packaging (DGR 5.0.2.11), they must be compatible with each other AND not react dangerously in the event of leakage.
Quantity Limits Still Apply
Even when goods are compatible, the per-package and per-aircraft quantity limits (PAX or CAO) must still be observed. Compatibility does not exempt from quantity restrictions.
Segregation Matrix — Table 9.3.A Summary
For each class pair: Compatible = may be loaded together, Incompatible = must never be on the same aircraft, Conditional = subject to special provisions.
| Class | Compatible With | Incompatible With | Conditional |
|---|---|---|---|
| 1 Explosives | — | 1, 2.1, 2.3, 3, 4.1, 4.2, 4.3, 5.1, 5.2, 6.1, 8 | 2.2, 6.2, 7, 9 |
| 2.1 Flammable Gas | 2.1, 2.2, 9 | 1, 5.1, 5.2 | 2.3, 3, 4.1, 4.2, 4.3, 6.1, 6.2, 7, 8 |
| 2.2 Non-Flam. Gas | 2.1, 2.2, 2.3, 3, 4.1, 4.2, 4.3, 6.1, 6.2, 7, 8, 9 | — | 1, 5.1, 5.2 |
| 2.3 Toxic Gas | 2.2, 9 | 1 | 2.1, 2.3, 3, 4.1, 4.2, 4.3, 5.1, 5.2, 6.1, 6.2, 7, 8 |
| 3 Flam. Liquid | 2.2, 3, 6.1, 8, 9 | 1, 5.1, 5.2 | 2.1, 2.3, 4.1, 4.2, 4.3, 6.2, 7 |
| 4.1 Flam. Solid | 2.2, 4.1, 6.1, 8, 9 | 1, 5.1, 5.2 | 2.1, 2.3, 3, 4.2, 4.3, 6.2, 7 |
| 4.2 Spont. Combust. | 2.2, 4.2, 6.1, 8, 9 | 1 | 2.1, 2.3, 3, 4.1, 4.3, 5.1, 5.2, 6.2, 7 |
| 4.3 Dangerous Wet | 2.2, 4.3, 6.1, 8, 9 | 1 | 2.1, 2.3, 3, 4.1, 4.2, 5.1, 5.2, 6.2, 7 |
| 5.1 Oxidizer | 5.1, 9 | 1, 2.1, 3, 4.1 | 2.2, 2.3, 4.2, 4.3, 5.2, 6.1, 6.2, 7, 8 |
| 5.2 Org. Peroxide | 9 | 1, 2.1, 3, 4.1 | 2.2, 2.3, 4.2, 4.3, 5.1, 5.2, 6.1, 6.2, 7, 8 |
| 6.1 Toxic | 2.2, 3, 4.1, 4.2, 4.3, 6.1, 8, 9 | — | 1, 2.1, 2.3, 5.1, 5.2, 6.2, 7 |
| 6.2 Infectious | 2.2, 9 | — | 1, 2.1, 2.3, 3, 4.1, 4.2, 4.3, 5.1, 5.2, 6.1, 6.2, 7, 8 |
| 7 Radioactive | 2.2, 9 | — | 1, 2.1, 2.3, 3, 4.1, 4.2, 4.3, 5.1, 5.2, 6.1, 6.2, 7, 8 |
| 8 Corrosive | 2.2, 3, 4.1, 4.2, 4.3, 6.1, 8, 9 | — | 1, 2.1, 2.3, 5.1, 5.2, 6.2, 7 |
| 9 Misc. DG | 2.1, 2.2, 2.3, 3, 4.1, 4.2, 4.3, 5.1, 5.2, 6.1, 6.2, 7, 8, 9 | — | 1 |
Critical Forbidden Combinations
These class pairs are absolutely forbidden on the same aircraft. No exceptions or special provisions can override these prohibitions.
Explosive + flammable liquid creates extreme fire/detonation risk. Never load together.
Oxidizer accelerates explosive reaction. Absolute prohibition.
Flammable gas + oxidizer = extreme ignition risk in confined aircraft hold.
Organic peroxides can decompose explosively when exposed to flammable liquids.
Flammable solid + oxidizer can cause spontaneous ignition.
Corrosive substances can damage explosive packaging, creating initiation risk.
Overpack Co-Packing
DG of different classes may be combined in an overpack only if compatible per Table 9.3.A.
- • All inner packages must be individually labelled and marked
- • "OVERPACK" marking required (min 12 mm letters)
- • Net quantities of each substance must be declared on the DGD
- • Incompatible pair = entire overpack rejected
ULD (Unit Load Device) Loading
When loading DG into a ULD (pallet/container), segregation rules apply at the ULD level.
- • Incompatible DG packages must not share the same ULD
- • Different ULDs on the same aircraft: both must still be compatible
- • ULD tag must list all DG contents (UN numbers, classes)
- • NOTOC (Notification to Captain) must include all DG by ULD position
References
- • IATA DGR 67th Ed. Section 9.3 — Segregation and Separation
- • IATA DGR 67th Ed. Table 9.3.A — Segregation of Packages (Aircraft)
- • IATA DGR 67th Ed. Section 5.0.2.11 — All-Packed-in-One Provisions
- • IATA DGR 67th Ed. Section 7.1.7 — Overpack Requirements
- • ICAO Doc 9284-AN/905 Part 7 Chapter 4 — Loading