What’s wrong with this picture?

Technically, until well into the 1960s, nothing. The pilot just didn’t have to be “under the influence” of alcohol to not fly.

Glad we made some changes.

But it got me curious, when did this really become more regulated?

If you are reading this, and curious about when regulations about alcohol usage and flying were put in place like I was, well, keep reading.

Here is what I was able to find on the topic.

Most of us know 14 CFR § 91.17 establishes prohibitions on alcohol and drug use for crewmembers of civil aircraft, including pilots. The regulation has evolved over time through amendments to address emerging safety concerns, technological advancements in testing, and alignment with broader Department of Transportation (DOT) policies. But getting to that point was a mix of changes in FAR history, Federal Register notices, and related FAA guidance.

But, I was curious when it actually became a regulation that pilots had to wait 8 hours from consuming alcohol before they could fly an aircraft.

When I did some digging, I was surprised at how late into flying activities that we actually waited to make it a “rule.”

It wasn’t until 1970 that the 8-hour rule became a formal regulation through Amendment 91-75, published in the Federal Register (35 FR 7390, May 13, 1970) and effective June 12, 1970.

But how did we get there, and where have we gone since then?

Pre-1970: Origins in “Under the Influence” Prohibitions

The roots of the regulation trace back to the Civil Air Regulations (CAR), which predated the modern Federal Aviation Regulations (FAR). These were consolidated into 14 CFR Part 91 in the early 1960s following the creation of the FAA in 1958.

In the initial codification of Part 91 (effective January 1, 1963, via Federal Register Vol. 27, No. 219, November 13, 1962), the rule appeared as § 91.11 “Liquor and drugs.” It prohibited:

“Acting as a crewmember while “under the influence of intoxicating liquor” or using any drug that affects faculties contrary to safety. or;

Allowing an obviously intoxicated person (or under drugs, except medical patients) to be carried aboard, unless in an emergency.”

There was no specific time-based restriction like the 8-hour rule; enforcement relied on subjective assessments of impairment. In otherwords, if the co-pilot wanted to “let the captain sleep it off on the first leg,” that might get by in those days. Yes, according to some of the old pilots I have talked with, that happened for real. At point in history,  a focus was on general safety without quantifiable limits.

By the mid-1960s, growing awareness of alcohol’s impact on aviation safety led to educational efforts. In 1966, the FAA suggested an 8-hour waiting period in advisory materials (e.g., pamphlets and safety bulletins) as a best practice, but it was not yet regulatory. This “suggestion” stemmed from studies on alcohol metabolism and pilot performance, though the exact foundation was described as somewhat arbitrary in later analyses (e.g., focusing on time elapsed rather than individual factors like amount consumed or sleep).

 1970: Introduction of the 8-Hour Rule (Amendment 91-75)

The 8-hour rule became a formal regulation through Amendment 91-75, published in the Federal Register (35 FR 7390, May 13, 1970) and effective June 12, 1970.

This amendment revised § 91.11(a) to explicitly prohibit acting as a crewmember:

“(1) Within 8 hours after the consumption of any alcoholic beverage.”

It retained the “under the influence” and drug prohibitions.

The FAA cited increasing evidence from accident investigations and studies showing alcohol’s lingering effects on judgment, coordination, and reaction time, even after apparent sobriety. The rule aimed to provide a clear, enforceable buffer to prevent impairment. It applied to all civil aircraft operations under Part 91, including pilots.

This marked the first quantifiable time restriction, shifting from purely subjective (“under the influence”) to objective criteria. The FAA noted that while 8 hours was a minimum, pilots should consider hangover effects and allow more time if needed (e.g., 12-24 hours for heavier consumption).

1980s: Addition of Blood Alcohol Concentration (BAC) Limits and Testing

In the 1980s, the regulation was strengthened amid broader DOT efforts to combat substance abuse in transportation.

Amendment 91-199 (50 FR 15328, April 17, 1985; effective May 17, 1985) added a BAC limit:

“Prohibited acting as a crewmember with “0.04 percent by weight or more alcohol in the blood.”

This was half the typical U.S. driving limit (0.08-0.10 at the time) to provide an extra safety margin for aviation. It aligned with DOT standards for commercial operations and reflected resistance from earlier decades, where some argued alcohol-related accidents were rare.

The rule also authorized law enforcement to request blood tests from crewmembers involved in accidents or suspected violations, with results reportable to the FAA.

In 1989, as part of a broader recodification of Part 91 (Amendment 91-211, 54 FR 34284, August 18, 1989; effective August 18, 1989), the section was renumbered from § 91.11 to § 91.17 without substantive changes.

1990s: Alignment with Omnibus Transportation Employee Testing Act

The Omnibus Transportation Employee Testing Act of 1991 mandated drug and alcohol testing programs for safety-sensitive transportation workers, including pilots in commercial operations (Parts 121 and 135).

Amendment 91-252 (59 FR 7380, February 15, 1994; effective March 17, 1994) integrated these requirements into § 91.17, requiring pilots to submit to tests by law enforcement or the FAA if reasonable suspicion existed. It also clarified that violations could lead to certificate revocation.

This era emphasized random, post-accident, and reasonable-suspicion testing, though Part 91 general aviation pilots were not subject to routine random testing unless in commercial roles.

2000s: Breath Testing and Disqualification Provisions

In 2004, amendment 91-278 (69 FR 74802, December 14, 2004; effective January 13, 2005) updated § 91.17 to recognize breath alcohol testing alongside blood tests, reflecting technological advancements. It set the BAC violation at 0.04 or greater in breath (grams of alcohol per 210 liters).

Amendment 91-287 (71 FR 35758, June 21, 2006; effective July 21, 2006) further revised the rule for consistency with disqualification standards, emphasizing that a BAC of 0.04+ or refusal to test could lead to medical certificate denial or revocation under Part 67.

Post-2010: Minor Updates and Ongoing Guidance

No major substantive changes have taken place since 2006, but the FAA has issued advisory circulars (e.g., AC 120-33) and brochures emphasizing the rule’s limitations. For example, the FAA notes that 8 hours is a minimum—hangover effects can persist longer, and pilots should aim for 12-24 hours.

In 2018, the FAA Reauthorization Act reinforced testing but did not alter § 91.17 directly.

Current text of the Federal Aviation Regulations retains the 8-hour rule, 0.04 BAC limit (blood or breath), drug prohibitions, and keeps passenger restrictions for those who appear to be under the influence of alcohol. And there is little doubt that this is going away anytime soon, but it is curious how we got to the current regulations that most of us know well and just assume have always been there.

It hasn’t, and it actually took a while to fully develop into the regulations we all learn in our initial pilot training now.

The regulation’s evolution reflects a shift from qualitative to quantitative standards, improving enforceability and safety.

In a timely update, the FAA also just released InFO 26002 on January 13th on the topic of Impaired or Intoxicated Passengers Aboard Title 14 of the Code of Federal Regulations (14 CFR) Part 91 or Part 135 flights. You can find it by clicking here. Pilots and their alcohol habits are the only concern that pilots might have to consider in their flight operations.