Commercial pilot · ACS CA.I.H
Human Factors (Commercial)
This lesson covers the physiology that affects pilots, the rules on alcohol and drugs, and how commercial pilots make and check their decisions.
Why this one matters
A commercial pilot is paid to make good decisions under pressure, often tired and with people watching. Most accidents trace to the pilot, not the airplane: a hazardous attitude, an unrecognized physiological problem, or a mind that heard what it expected. Recognizing these in yourself is a professional skill.
Can’t miss
- •No flying within 8 hours of drinking alcohol, while under its influence, or with a blood alcohol of 0.04 or more.(14 CFR 91.17)
- •A motor vehicle action is a conviction for driving while intoxicated or impaired, or a license suspended, revoked, cancelled or denied for an alcohol- or drug-related cause. Report each in writing to the FAA Security and Investigations Division within 60 days. An arrest alone, with no conviction or license action, isn't one.(14 CFR 61.15(c), (e))
- •Oxygen (cabin pressure altitudes): the required crew must be provided with and use it above 12,500 feet MSL up to and including 14,000 for any time over 30 minutes, and at all times above 14,000; above 15,000, every occupant must be provided with it.(14 CFR 91.211(a))
- •After scuba diving, wait at least 12 hours before flying up to 8,000 feet, and 24 hours for higher altitudes or after a dive that needed a controlled ascent.(AIM 8-1-2)
- •Five hazardous attitudes, each with an antidote: anti-authority, impulsivity, invulnerability, macho, resignation.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeronautical Decision-Making)
- •Confirmation and expectation bias make you see what you expect, like the clearance you expected or the forecast you hoped for. Read back and cross-check.(Risk Management Handbook (FAA-H-8083-2A))
- •Single-pilot resource management: use every resource (ATC, automation, checklists, passengers) and manage workload before it peaks.(Risk Management Handbook (FAA-H-8083-2A))
What you should know
Physiology K1 · R1
- Hypoxia: lack of oxygen, with euphoria, headache, poor judgment and cyanosis. Types: hypoxic (altitude), hypemic (blood, including carbon monoxide), stagnant and histotoxic (alcohol, drugs). Use oxygen and descend.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Hyperventilation: breathing too fast, often from stress; tingling and dizziness. Slow your breathing, or talk out loud. Its symptoms look like hypoxia's: at altitude, treat for hypoxia first (oxygen on, descend), then slow your breathing.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors; AIM 8-1-2, 8-1-3)
- Middle ear and sinus: a cold or allergy can block the passages, so the pressure can't equalize, mostly in the descent: sharp pain, muffled hearing, even a ruptured eardrum. Don't fly congested; if it happens, climb back up a little and descend slowly, using a Valsalva.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Spatial disorientation: the inner ear misleads without a visual horizon: the leans after a slow roll, a graveyard spiral, a false climb when accelerating (somatogravic). Recognize it by a conflict between the feeling and the instruments; trust the instruments, or avoid the conditions without an instrument rating.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors; AIM 8-1-5)
- Optical illusions on landing: a narrow or upsloping runway makes you feel high (you fly low); a wide or downsloping one, low (you fly high); featureless terrain, water or haze make you fly low. Use the VASI or PAPI, a known pattern and the altimeter.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors; AIM 8-1-5)
- Motion sickness: nausea, sweating, pallor. Fresh air, eyes outside on the horizon, smooth flying, and land if needed.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Carbon monoxide from a cabin heater leak: headache and drowsiness. Heater off, fresh air, land.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Stress: shows as tension, poor sleep, distraction or irritability; acute stress from an emergency, chronic from life. Notice it, simplify the flight or stay on the ground.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Fatigue: slower reactions, missed radio calls, poor judgment, the same impairment as alcohol. Causes are short sleep, long duty and time of day. The fix is rest; caffeine only masks it.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Dehydration and nutrition: headache, fatigue, cramps, dizziness; hot cockpits and altitude dry you out. Drink before you're thirsty and eat regular meals: low blood sugar dulls judgment too.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Hypothermia: cold exposure (an open cockpit, winter, a forced landing) brings shivering, confusion and clumsy hands. Dress for the outside temperature, carry survival gear, and get warm.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors)
- Decompression sickness after scuba diving: nitrogen bubbles bring joint pain and worse. Wait at least 12 hours before flying up to 8,000 feet, 24 hours above that or after a dive that needed a controlled ascent.(AIM 8-1-2)
Alcohol, drugs and medications K2 · K3
- The 8-hour, influence and 0.04 rules are minimums. Alcohol impairs judgment and worsens hypoxia; many pilots use 24 hours.(14 CFR 91.17)
- Over-the-counter drugs, especially antihistamines, can impair you. Don’t fly while using a drug that affects your faculties, and check with an AME.(14 CFR 61.53; 91.17)
- Report alcohol- or drug-related motor vehicle actions within 60 days.(14 CFR 61.15(e))
Decisions and attitudes K4 · R2
- Hazardous attitudes and antidotes: anti-authority ("follow the rules, they’re usually right"), impulsivity ("not so fast, think first"), invulnerability ("it could happen to me"), macho ("taking chances is foolish"), resignation ("I’m not helpless. I can make a difference.").(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeronautical Decision-Making)
- Use a decision model such as DECIDE or 3P (perceive, process, perform). SRM uses every resource when you fly alone (ATC, automation, checklists, passengers); CRM is the same idea with a crew: brief roles, speak up, and cross-check each other.(Risk Management Handbook (FAA-H-8083-2A))
- Before each flight, check yourself with IMSAFE (Illness, Medication, Stress, Alcohol, Fatigue, Emotion or Eating) and the flight with PAVE (Pilot, Aircraft, enVironment, External pressures), against personal minimums you wrote down in advance.(Risk Management Handbook (FAA-H-8083-2A); Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeronautical Decision-Making)
Attention and bias R3 · R4
- Prioritize: aviate, navigate, communicate. Brief tasks before high-workload phases.(Risk Management Handbook (FAA-H-8083-2A))
- Confirmation bias: you favor information that supports your plan. Expectation bias: you hear the clearance you expected. Read back carefully and question what fits too neatly.(Risk Management Handbook (FAA-H-8083-2A))
Scenarios
Decide what you would do first, then see the worked answer.
Your passenger complains of a headache and drowsiness with the cabin heat on.
What do you suspect? See the worked answer
Carbon monoxide. Heater off, fresh air, oxygen if available, land and get checked.
Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aeromedical Factors
Ground control gives a taxi clearance you expected, but something sounded different.
What do you do? See the worked answer
Read back what you heard and ask if unsure. Expectation bias makes you hear the usual.
Risk Management Handbook (FAA-H-8083-2A)
You went scuba diving this morning, with no controlled ascent, and a flight at 9,500 feet is offered this afternoon.
Can you go? See the worked answer
Not yet. Above 8,000 feet the guidance is to wait 24 hours.
AIM 8-1-2
Common mistakes
Treating the alcohol rule as a target.
Impairment lasts longer than 8 hours.
Instead: Use a much longer personal rule.
Not recognizing your own hazardous attitude.
Attitudes feel normal from inside.
Instead: Learn the five and say the antidote out loud.
Ignoring fatigue for income.
Fatigue impairs like alcohol.
Instead: Set duty limits for yourself.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice human factors (commercial) out loud with our examiner.
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Sources
- Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C): Aeromedical factors; aeronautical decision-making
- Risk Management Handbook (FAA-H-8083-2A)
- Aeronautical Information Manual (AIM): 8-1
- 14 CFR: 61.15, 61.53, 91.17, 91.211
- Commercial Pilot ACS (FAA-S-ACS-7B): Area I, Task H
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.