AVweb reported: 2018.07.30 - A former pilot for Alaska Airlines was sentenced on Wednesday to a year and a day in federal prison, for flying two flights in 2014 with a blood alcohol level more than three times the legal limit.

Arnston flew from San Diego to Portland on June 20, 2014, and then from Portland to John Wayne Airport, in Orange County. After landing, Arnston was selected for random drug and alcohol testing by airline personnel. Two breathalyzer tests showed Arnston had a blood alcohol concentration of 0.135 percent and 0.142 percent. The federal limit is 0.04.

BoardingArea reports: 2018.09.02 Prosecutors allege he struggled with alcohol addiction over those two decades and routinely piloted commercial flights under the influence of alcohol.

Are there any published statistics on the percentage of pilots tested or otherwise gleamed for alcohol that failed?

How often do pilots fly drunk?

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    $\begingroup$ Not more than once in their career. $\endgroup$ Jul 30, 2018 at 21:18
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    $\begingroup$ @GregHewgill I appreciate your statement as humor, but, just to be clear and in case someone might think it would happen only once in their career, my observation has been that while it may be rare that pilots fly drunk, it is even rarer that they get caught. See the 2nd to the last paragraph of terryliittschwager.com/Journal/1998-05-23_1998-12-16_none.html for an instance of a competent pilot getting caught accidentally. I flew with him regularly, and never observed anything but good performance even though I suspect he might have had trouble with a breathalyzer test. $\endgroup$
    – Terry
    Jul 30, 2018 at 22:37
  • 7
    $\begingroup$ @Terry: Thanks, and you're right that my statement is meant only as humor. Though, in today's environment, I suppose pilots would only get caught once drinking and flying. $\endgroup$ Jul 30, 2018 at 22:44
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    $\begingroup$ Are you asking about commercial pilots or pilots in general? I've heard hangar stories (one involving a pilot who could barely stand as they refilled the 172 at a self serve, then took off with twin trails of fuel mist because they forgot to put the caps back on), but other than the occasional news story I've never heard of a GA pilot getting caught for this (at least not unless they were referred to as the "accident pilot"). $\endgroup$
    – Ron Beyer
    Jul 31, 2018 at 0:02
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    $\begingroup$ @gusto2 there are some interesting problems with setting a 0.00000 limit, even if you assume perfect measuring hardware: undeclared trace quantities in foods (desserts, wine in sauce, ripe fruit); some people take much longer than others to remove alcohol, leaving traces for a long time; byproducts of ketogenic diets $\endgroup$
    – Chris H
    Jul 31, 2018 at 11:14

2 Answers 2


Its rare but it does happen. You can search the NTSB database here, the phrase "positive for alcohol" yields the best results as toxicology is fairly common in an accident so a lot of reports include "negative for alcohol" making "alcohol" alone a bad search term. I was able to find a few examples here, here, here, and here as well as some more report results.

according to this article

... Of over 10,000 pilots randomly tested for alcohol in 2010, only 12 failed the test.

They don't cite any sources though.

This looks like it might be the original study and has slightly different numbers but this seems to include all "Aviation Employees" so pilots, crew, ATC and the related may have been included.

Validity of Suspected Alcohol and Drug Violations in Aviation Employees

Results: During the 11-year study period, a total of 2,284 alcohol tests and 2,015 drug tests were performed under the reasonable-cause testing program. The PPV was 37.7% [95% confidence interval (CI), 35.7–39.7%] for suspected alcohol violations and 12.6% (95% CI, 11.2–14.1%) for suspected drug violations. Random testing revealed an overall prevalence of 0.09% (601/649,796) for alcohol violations and 0.6% (7,211/1,130,922) for drug violations. The LR+ was 653.6 (95% CI, 581.7–734.3) for suspected alcohol violations and 22.5 (95% CI, 19.6–25.7) for suspected drug violations.

The FAA also has an interesting fact sheet you can find here quoting some accident numbers from the late 80's and early 90's as well as the pilots BAC.

Its worth noting that the regulations have changed a fair bit over the years. The current regulation for this is FAR 91.17 which establishes an 8 hour "bottle to throttle" time frame as well as a maximum .04 BAC.

§ 91.17 Alcohol or drugs.

(1) Within 8 hours after the consumption of any alcoholic beverage;

(2) While under the influence of alcohol;

(3) While using any drug that affects the person's faculties in any way contrary to safety; or

(4) While having an alcohol concentration of 0.04 or greater in a blood or breath specimen. Alcohol concentration means grams of alcohol per deciliter of blood or grams of alcohol per 210 liters of breath.

If you take a look at the original amendment creating 91.17 it reads

Sec. 91.17 Liquor and drugs. (a) No person may act as a crewmember of a civil aircraft -

(1) Within 8 hours after the consumption of any alcoholic beverage;

(2) While under the influence of alcohol; or

(3) While using any drug that affects his or her faculties in any way contrary to safety.

the important difference being that it does not establish a maximum BAC but leaves it open to the interpretation of "under the influence" which potentially left room for intoxicated pilots prior to the current verbiage.

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    $\begingroup$ This seems pretty accurate. In the 70-80's I would say 1/15-20 of my pilot friends flew drunk (over 0.1). At the time, I was told the 60-70's were probably 1/5-10. By 2000, I knew less other pilots but got the impression none were drinking on the job. Your stats show it is now about 1/1000 which seems reasonable. In the 70-80's the law simply said you could not consume alcohol within 8hrs of flying, most didn't but that didn't keep them from being hung over. If there are 5000 airline flights in the US per day, and many are multiple puddle jumps, perhaps 20-30 pilots are drunk each day. $\endgroup$
    – jwzumwalt
    Jul 30, 2018 at 22:05
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    $\begingroup$ @jwzumwalt Taking a guestimate rate for all pilots, including GA pilots with no crew, no passenger or supervisory interactions and virtually no program for random or "for cause" testing, and extrapolating that out to airline flying gives you a result that is WILDLY inaccurate. Five thousand flights per day in the U.S. is low by a factor of several, and "20-30" is almost certainly high by a similar factor. I won't suggest that the rate is uniformly 0.0, but there is NO WAY 20 airline pilots are flying drunk & unnoticed each day. Nobody tolerates that these days in airline flying. NOBODY. $\endgroup$
    – Ralph J
    Jul 31, 2018 at 3:22
  • $\begingroup$ Also note that (4) counts people having alcohol levels due to other reasons than drinking as illegal to fly. Some medical conditions can cause this to happen (though it's quite likely that such people would fail their medical, you'd have to consult an AME for that). $\endgroup$
    – jwenting
    Jul 31, 2018 at 4:37
  • $\begingroup$ There may also be a number of cases where alcohol contributed to a fatal accident, but we won't know because alcohol testing is not done on deceased pilots $\endgroup$
    – TomMcW
    Jul 31, 2018 at 19:18
  • $\begingroup$ @TomMcW im not sure if you are referencing unrecovered bodies but Toxicology including alcohol testing is routinely done on deceased pilots. some of the reports I have linked are good examples of such testing. $\endgroup$
    – Dave
    Jul 31, 2018 at 19:24

Thankfully this really does not happen all that much, most airlines have processes in place to catch those with a problem and there are programs available. This is because drink is recognized as a sickness and therefore treatable.

We have also seen willingness on the part of ground staff to report any unusual behavior and there have been several cases where the pilot has been prevented from flying.

A drinking problem usually becomes apparent in unusual behavior long before the stumbling appears. Typical pointers.. 1. Punctuality issues. 2. Poor personal hygiene, sloppy dress. 3. Car has numerous dents. 4. Proceeds direct to aircraft instead of report to the despatch office (using lateness as an excuse). 5. Addiction to breath mints. 6. Irrational outburst/ bad temper / mood swings.

Each in its own is not an indicator but when a few are present then its time to look deeper. Sad to say its usually the first-officers who notice this first and this is where good a healthy reporting culture is required to allow them to speak up.

Another pointer is when someone leaves a bigger airline in favour of a smaller airline .. while a lot of pilots really want a change of pace, a wise fleet manager will have a quite word with his ex-employer.

  • $\begingroup$ "...a wise fleet manager will have a quite word with his ex-employer." In the US, it is against the law for employee information to be exchanged without the employee's explicit permission. Further more, most HR departments won't do it for litigation, if there were an accident, i.e. "why didn't they handle a safety risk...". Without employee permission, there are only two questions that may be asked, the more serious is, "Would you re-hire this employee?". HR is only allowed a yes/no. It has become nearly impossible to get reliable past employee information. $\endgroup$
    – jwzumwalt
    Aug 3, 2018 at 23:18

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