What does 'Cargo Aircraft Only' (CAO) mean in dangerous goods shipping?

• A. Shippings are allowed on any aircraft.
• B. Some DG shipments are restricted from passenger aircraft and must be carried on cargo aircraft only due to safety regulations.
• C. Only domestic flights.
• D. Only overnight service.

Answer: (B)

CAO means that certain dangerous goods must be shipped only on all-cargo aircraft and cannot be carried on passenger aircraft due to safety requirements. Some hazard classes or quantities require the specialized handling, segregation, and firefighting capabilities available on cargo planes, and shipping them on passenger flights could pose unacceptable risks to passengers and crew. This designation guides shippers and operators to use cargo-only flights so the shipment is managed with the appropriate equipment, procedures, and trained personnel. It isn’t about domestic versus international service or about speed; it’s about the aircraft type allowed for transporting the dangerous goods.