Definition
Substances whose possession, use, or distribution is prohibited by federal law, including drugs listed under the Controlled Substances Act such as marijuana, cocaine, heroin, methamphetamine, and certain opioids and hallucinogens. Under 14 CFR Part 61, conviction for violating any federal or state law relating to the growing, processing, manufacture, sale, disposition, possession, transportation, or importation of narcotic drugs, marijuana, or depressant or stimulant drugs is grounds for denial of an application for a pilot certificate or rating for up to one year, and is grounds for suspension or revocation of any existing pilot certificate.
Plain English
Drugs that are against the law to have or use. If a pilot is convicted of an offense involving these drugs, the FAA can refuse to issue a certificate, or take away the one they already have.
Context Anchor
Seen in aeromedical, fitness-to-fly, and FAA medical certification discussions when deciding whether a pilot is safe and legally allowed to fly.
Derivation
Illegal comes from Latin roots meaning “not lawful.” That helps here because the term is not mainly about how strong a drug is; it is about whether the law allows its possession or use.
Why Pilots Care
Detection of illegal drugs leads to immediate disqualification from flight duties, FAA enforcement action including certificate revocation, and dramatically elevated accident risk from impaired judgment and coordination.
Intuition Check
Do not read “illegal drugs” as only meaning street drugs. In aviation, it also includes controlled drugs used without proper legal authorization. Also, “not illegal” does not automatically mean “safe to fly with.”
Example Sentence 1
A conviction involving illegal drugs must be reported on the pilot's next medical application and can result in denial of the certificate.
Example Sentence 2
Regulations require pilots to remain free of illegal drugs for a sufficient period before assuming any flight duties.