Carriage of narcotic drugs, marihuana, and depressant or stimulant drugs or substances

This regulation holds Part 121 air carriers (scheduled airlines and commercial operators) accountable if they knowingly allow their aircraft to be used for illegal drug transportation. It references §91.19(a), which prohibits carrying narcotic drugs, marijuana, and certain other controlled substances except when authorized by federal or state law (such as for medical transport or law enforcement purposes).

The key word is "knows"—the certificate holder must be aware the illegal activity is occurring. If an airline knowingly permits its aircraft to transport illegal drugs, the FAA can suspend or revoke the carrier's operating certificate, effectively shutting down the airline.

In practice, this means Part 121 operators must have procedures to prevent their aircraft from being used for drug smuggling and must act immediately if they discover such activity. This regulation reinforces that air carriers bear responsibility for how their aircraft are used.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*