IMSAFE is the FAA’s personal fitness-for-flight checklist: Illness, Medication, Stress, Alcohol, Fatigue, and Emotion. You run it on yourself before every flight, the same way you run a checklist on the airplane, and if any item says you are not fit, the flight waits. It appears in the FAA’s Pilot’s Handbook of Aeronautical Knowledge (PHAK) and in the Aeronautical Information Manual (AIM 8-1-1), and two regulations, 14 CFR 61.53 and 91.17, stand behind several of its letters.
IMSAFE is the “P” in the PAVE checklist: it answers “Am I ready for this flight?” before you look at the airplane, the weather, and the pressures around the trip. It is one of the memory aids every student pilot uses.
What IMSAFE stands for
The PHAK calls IMSAFE one of the best ways a single pilot can mitigate risk. Each letter is a question you answer honestly, in the FAA’s wording:
- I Illness: Am I sick? Do I have any symptoms?
- M Medication: Am I taking any medicines that might affect my judgment or make me drowsy?
- S Stress: Am I under psychological pressure from the job? Do I have money, health, or family problems?
- A Alcohol: Have I been drinking within 8 hours? Within 24 hours?
- F Fatigue: Am I tired and not adequately rested?
- E Emotion: Am I emotionally upset?
| Letter | Rule or FAA guidance behind it |
|---|---|
| I: Illness | 14 CFR 61.53; AIM 8-1-1b: the safest rule is not to fly while suffering from any illness |
| M: Medication | 14 CFR 91.17(a)(3) and 61.53(a)(2); FAA No Fly wait times |
| S: Stress | Not a grounding condition in the regulations; AIM 8-1-1f: consider delaying the flight |
| A: Alcohol | 14 CFR 91.17(a): 8 hours, below 0.04, and not under the influence |
| F: Fatigue | PHAK: if suffering from acute fatigue, stay on the ground |
| E: Emotion | AIM 8-1-1g: do not fly until satisfactorily recovered |
The AIM lists the same six items as a personal checklist, and the Risk Management Handbook titles its version the “I’M SAFE” checklist.
The rules behind the checklist
IMSAFE itself is a memory aid, not a regulation. Two regulations give it teeth:
- 14 CFR 61.53. If you hold an FAA medical certificate, you may not act as pilot in command or as a required pilot flight crewmember while you know or have reason to know of any medical condition that would make you unable to meet the requirements for the medical certificate your flight requires, or while taking medication or receiving treatment that has that effect. Under BasicMed with a U.S. driver’s license, the test is whether you know or have reason to know of any medical condition that would make you unable to operate the aircraft in a safe manner.
- 14 CFR 91.17. No person may act or attempt to act as a crewmember within 8 hours after consuming any alcoholic beverage, while under the influence of alcohol, while using a drug that affects their faculties contrary to safety, or at an alcohol concentration of 0.04 or greater.
The FAA’s over-the-counter medication guide sums up 61.53 this way: it requires that you determine that you are fit to fly prior to each flight. A medical certificate shows you met the standards on the day of your exam, not that you are fit today. See our FAA medical certificate guide, the medical certificate classes, and the BasicMed guide.
I is for illness
The AIM is blunt: even a minor illness can seriously degrade performance, and fever and distracting symptoms can impair judgment, memory, alertness, and the ability to make calculations. The safest rule is not to fly while suffering from any illness; if that seems too strict for a particular illness, contact an Aviation Medical Examiner (AME).
Colds deserve special respect. Congestion can keep your ears and sinuses from equalizing during descent, causing a painful ear or sinus block. The AIM (8-1-2) says these are prevented by not flying with an upper respiratory infection or nasal allergic condition, and that oral decongestants have side effects that can impair pilot performance. The FAA’s medication guide adds honest self-checks:
- Am I having trouble clearing my ears at ground level?
- Do I feel good enough to fly only if I take medication?
- Am I getting worse?
M is for medication
Prescription and over-the-counter drugs, and the conditions they treat, can all degrade performance. The AIM warns about tranquilizers, sedatives, strong pain relievers, and cough suppressants, and about side effects from antihistamines, muscle relaxants, and motion sickness drugs, among others. Its safest rule is not to fly as a crewmember while taking any medication unless approved to do so by the FAA. FAA guidance for pilots adds specific wait times:
- Any new medication: never fly after the first dose until at least 48 hours have passed and no side effects are noted.
- Medications with side effects: after the last dose, wait 5 times the maximum pharmacologic half-life, or 5 times the maximum dosing interval if the half-life is not known. A medicine taken every 4 to 6 hours means a 30-hour wait.
- Sedating antihistamines: the FAA lists a 60-hour wait after diphenhydramine (Benadryl), common in allergy pills and sleep aids.
- Label warnings: do not fly on any medication whose label warns of drowsiness or says to be careful when driving or operating machinery, even if you have taken it before with no apparent effect.
- The underlying condition: if the untreated condition would make you unsafe, do not fly, whether you take the medication or not.
These rules come from the FAA’s over-the-counter medications guide for pilots and its Do Not Issue and Do Not Fly lists. They are FAA guidance, not personal medical advice; for a specific medication, ask an AME before you fly.
S is for stress
The PHAK splits stress into two kinds. Acute stress involves an immediate threat and triggers a fight-or-flight response, and a healthy person can normally cope with it. Chronic stress is an ongoing load, such as financial worries or relationship or work problems, that exceeds your ability to cope; the PHAK says pilots at that level are not safe, should not exercise their airman privileges, and should consult a physician.
The regulations do not list stress as a grounding condition, so this letter depends on your honesty. The AIM warns that most pilots do not leave stress “on the ground,” and that distraction can lead to risks such as flying into deteriorating weather to keep a schedule. When more than the usual difficulties pile up, consider delaying the flight. The AIM also warns that stress and fatigue together can be an extremely hazardous combination.
A is for alcohol
The IMSAFE question has two parts for a reason: “Have I been drinking within 8 hours? Within 24 hours?” Eight hours is the legal minimum in 91.17, and it is only one of three alcohol limits that apply at once: no drinks within 8 hours, an alcohol concentration below 0.04, and not under the influence. The AIM recommends at least 12 to 24 hours between “bottle and throttle,” depending on how much you drank, and the FAA’s alcohol brochure calls waiting 24 hours from the last drink “a more conservative approach.” The same brochure says hangover effects can last 48 to 72 hours. Testing and DUI reporting are covered in our guide to 8 hours bottle to throttle and 14 CFR 91.17.
F is for fatigue
The AIM calls fatigue one of the most treacherous hazards to flight safety because it may not be apparent until serious errors are made. Acute fatigue follows strenuous effort, heavy mental workload, or lack of sleep, and the PHAK says rest and 8 hours of sound sleep ordinarily cure it. Chronic fatigue builds when you never fully recover; the AIM says recovery requires a prolonged period of rest, and the PHAK says it usually requires treatment by a physician.
Tired people are poor judges of their own fatigue. The FAA’s fatigue brochure reports that fatigued individuals consistently underreported how tired they were, and that no degree of experience, motivation, medication, coffee, or will power can overcome fatigue. In practice:
- Schedule lessons for times you are normally rested. The PHAK says to avoid flying without a full night’s rest, after working excessive hours, or after an especially exhausting or stressful day.
- If problems preclude a good night’s sleep, the FAA brochure says to rethink the flight and postpone it.
- Watch for difficulty concentrating, slower reactions, memory problems, task fixation, and more errors than usual.
E is for emotion
The AIM lists the kinds of events that can make a pilot unable to fly safely: a serious argument, the death of a family member, separation or divorce, loss of a job, or a financial catastrophe. The anger, depression, and anxiety they cause decrease alertness and can lead to taking risks, so a pilot who experiences an emotionally upsetting event should not fly until satisfactorily recovered. Rescheduling is always an option.
If your instructor uses E for Eating, the PHAK’s aeromedical chapter backs that up too: eat regular balanced meals, bring a snack and plenty of water, and remember that the first noticeable effect of dehydration is fatigue.
Answer IMSAFE before you leave for the airport, not on the ramp. Once the airplane is fueled and your instructor is waiting, the pressure to say “I’m fine” only grows.
IMSAFE and your personal minimums
The Risk Management Handbook treats pilot factors such as stress, fatigue, or not having flown for several weeks as reasons to raise your minimums for that flight, for example by adding at least 500 feet to your ceiling minimum and at least half a mile to visibility. The full process is in our PAVE checklist guide.
IMSAFE on the checkride
Fitness for flight is tested. The Human Factors task in the Private Pilot Airman Certification Standards (FAA-S-ACS-6C) covers stress, fatigue, dehydration and nutrition, the regulations on alcohol and drugs, and the effects of over-the-counter medications (PA.I.H.K1 to K3). It also requires a self-assessment, including fitness for flight and personal minimums, for an actual flight or an examiner’s scenario (PA.I.H.S2). Be ready for a scenario involving a cold, a short night, or a medication on the oral exam, and answer it letter by letter. Our checkride guide covers the rest.
Gear for your fitness-for-flight check
What you'll need
Keep the IMSAFE card on your kneeboard and the FAA source material in your flight bag.
Frequently asked questions
What does IMSAFE stand for?
Illness, Medication, Stress, Alcohol, Fatigue, and Emotion. It is the FAA’s personal checklist for deciding whether you are fit to fly, published in the AIM (8-1-1) and the Pilot’s Handbook of Aeronautical Knowledge.
Is the IMSAFE checklist required by the FAA?
The acronym is not a regulation, but the rules behind it are: 14 CFR 61.53 prohibits flying with a known medical deficiency, and 14 CFR 91.17 covers alcohol and drugs. The private pilot ACS also requires a fitness-for-flight self-assessment on the checkride.
What does the E in IMSAFE stand for?
In the AIM and the PHAK it stands for Emotion. The FAA Risk Management Handbook notes that some publications combine emotion with stress and use the E for Eating, as a reminder about food and hydration.
Can I fly after taking cold or allergy medicine?
Check the label first. FAA guidance says not to fly on any medication whose label warns of drowsiness or cautions about driving or operating machinery, to wait 48 hours after the first dose of a new medication, and to wait 5 maximum half-lives or dosing intervals after the last dose of one with side effects. Ask an AME about a specific drug.
Should I run IMSAFE before a dual lesson too?
Yes. The PHAK says all pilots must do a proper physical self-assessment prior to each and every flight, and illness, medication, stress, alcohol, fatigue, and emotion affect you just as much with an instructor aboard.