FAA  Flight Standards Service  Regulatory Support Division  Airman Testing Standards Branch  FAA-8083-25B, Pilot’s Handbook of Aeronautical Knowledge—Addendum A  The details of this safety research report and the resulting safety recommendations can be  accessed at www.ntsb.gov. The following will be included in the “Drugs” section of  Chapter 17, Aeromedical Factors  (page  17-16) in the next revision of FAA-8083-25: There is evidence taking illicit drugs significantly elevates the risk of having an aviation  accident. Even though the Drug Enforcement Administration (DEA) defines marijuana  as a Schedule I drug on its controlled substances list, states have taken steps to allow the  possession, sale, and use of marijuana within their borders. The FAA has stated,  “Marijuana is an illicit drug per federal law and its use by airmen is prohibited.”  Note : Until the revision of FAA-H-8083-25 is published, this addendum is considered part of  the current addition of the handbook and should be used as a reference.  References:  2013–2017 Update to Drug Use Trends in Aviation Safety Research Report,  NTSB/SS-20/01 (dated February 13, 2020); National Transportation Safety Board  (NTSB) Recommendation A-20-12, Section 4.2  FAA-H-8083-25B, Pilot’s Handbook of Aeronautical Knowledge  February 10, 2021  Addendum A  Page 1 of 1  Flight Standards Service – Regulatory Support Division – Airman Test Standards Branch 