Learning hub · Human Performance · Lesson 3

Decisions, stress, alcohol and medication

Most accidents involve a decision, not a failure of the aeroplane. This lesson looks at how good decisions are made, what bends them, and how to decide before you get in the aeroplane whether you should fly at all.

About 12 minutes, plus the quiz. Part of Human Performance. It follows Hypoxia, fatigue and knowing your limits, which introduced the IMSAFE check.

1. A simple decision loop

Decision-making in the air is a skill that can be trained, not a gift. Several models exist, and your school may teach a different one from this lesson. They all share one idea: slow down, look at the facts, list your options and then check the result. One simple example is DECIDE, taught in the FAA handbook:

Detect: notice that something has changed.
Estimate: how serious is it, and how much time do you have?
Choose: decide on the outcome and the course of action you want.
Identify: find the solutions that will get you there.
Do: carry it out.
Evaluate: did it work? If not, go round the loop again.

Others you may meet include PAVE (Pilot, Aircraft, enVironment, External pressures, used as a checklist before flight) and FORDEC (Facts, Options, Risks and benefits, Decision, Execution, Check), which comes from German-speaking aviation and is used by some European operators. The name does not matter. What matters is that you have a method that you can use under pressure, and that you start it early. In a real emergency the first rule is still to fly the aeroplane: see checklists, TEM and emergencies.

2. Hazardous attitudes

The FAA lists five attitudes that bend judgement. They are American in origin, but they describe human nature everywhere. Each has an antidote that you say to yourself.

Attitude	The thought	The antidote
Anti-authority	“Don’t tell me.”	Follow the rules; they exist for a reason
Impulsivity	“Do it quickly.”	Not so fast; think first
Invulnerability	“It won’t happen to me.”	It could happen to me
Macho	“I can do it.”	Taking chances is foolish
Resignation	“What’s the use?”	I am not helpless; I can make a difference

Add the pressures that push you towards a bad decision: a booking you paid for, a passenger who is waiting, a wish to reach the destination (“get-there-itis”), and the plan that you made yesterday. Sticking to a plan when the situation has changed is called plan continuation bias. A good pilot is willing to say “no” or “turn back” and finds it easy because the decision was made in advance.

3. Stress and workload

A little stress sharpens performance; too much narrows it. This is the idea of the arousal curve: too little arousal and you are bored and careless, too much and you make mistakes. Under high stress your attention narrows (“tunnel vision”), you lose the big picture, and you do the first thing that comes to mind.

Acute stress comes from the situation in front of you: a rough approach, a sudden engine noise, a lost-looking passenger.
Chronic stress comes from life: worries about money, work, health or relationships. It builds slowly and reduces your reserve, so the small things in the cockpit weigh more.
Workload is the demand of tasks against the time you have to do them. When tasks pile up you reach task saturation and drop the least obvious one, often monitoring the flight path or a radio call.

To reduce workload: plan early, brief before busy phases, use checklists, and prioritise. The order is always aviate, navigate, communicate. If you are behind the aeroplane, simplify: stop, slow down, ask ATC for time, or climb and hold. Chronic stress is a reason to be more careful about whether to fly.

4. Alcohol, illness and medication

Alcohol. It slows reactions, harms judgement and coordination, narrows vision and makes you more sensitive to a lack of oxygen. The body removes it at a slow and fixed rate: coffee, a cold shower or fresh air do not help. A hangover also degrades performance after the alcohol is gone, and you can feel perfectly well while still impaired.

Under SERA.2020 (the European rules of the air), a person whose function is critical to the safety of aviation must not do that function while under the influence of a psychoactive substance by reason of which human performance is impaired, and must not engage in problematic use of such substances. The numerical limit and the waiting time for private flying differ between States, and this lesson does not state one. A common rule of thumb is “eight hours from bottle to throttle” (an American rule uses 8 hours), but check your national rule and your school’s manual. The safest rule is none: do not fly after drinking.

Illness. A cold can block your Eustachian tubes and sinuses, so a descent becomes painful and can damage the ear. A fever, dizziness or nausea means you stay on the ground. The simple test: if you would stay off work, you stay off the aeroplane.

Medication. The medicine and the illness it treats both matter. Common over-the-counter tablets, such as some antihistamines and cold remedies, can cause drowsiness. Prescription drugs may be unsuitable for flying. Do not guess. Ask your aeromedical examiner or doctor, say that you are a pilot, and follow their advice, including how long to wait after the last dose. Never combine a new medicine with a flight to “see how it goes”.

The IMSAFE check (illness, medication, stress, alcohol, fatigue and emotion; some versions add eating) is your daily gate. If any answer is “yes”, the answer to flying is “not today”, or “not alone”. This is training material. Rules on alcohol and medication come from your national authority and your medical certificate conditions, not from this page.

5. Personal minimums

A personal minimum is a limit that you set yourself, at home, in calm conditions, and that is stricter than the legal minimum or the aeroplane’s limit. Write them down. Examples: lowest cloud base, lowest visibility, maximum crosswind, maximum wind gust, and the least sleep you will fly on. A student pilot often sets a crosswind limit as a share of the aeroplane’s demonstrated value, and raises it with experience and an instructor’s agreement. The point is that the decision has already been made. If you break one, you do not need to argue with yourself. You have the answer.

Review them after a bad day or a close call, and increase them if you are tired, out of practice or flying a new type. A personal minimum that moves on the day is not a minimum.

6. Try it yourself

Work each one out on paper first, then open the answer to compare. The numbers are invented.

An invented student pilot sets a personal crosswind limit of 60 per cent of the aeroplane’s demonstrated crosswind of 15 kt. The forecast wind is 240° at 18 kt and the runway is 280°. Is this within the limit? (Use crosswind = wind speed × sin of the angle; sin 40° is about 0.64.)
Show the answer
1. Personal limit = 0.6 × 15 = 9 kt.
2. The angle between wind and runway = 280 − 240 = 40°.
3. Crosswind = 18 × 0.64 = about 11.5 kt.
4. 11.5 kt is more than 9 kt, so the answer is no. The decision is already made: do not fly this circuit solo, or fly with an instructor, or wait for the wind to change.
On the morning of a solo flight an invented student has slept five hours, has a mild cold and took a cold tablet an hour ago that says it may cause drowsiness. Go through IMSAFE and say whether to fly.
Show the answer
1. Illness: yes, a cold, with a possible blocked ear.
2. Medication: yes, a tablet that may cause drowsiness.
3. Fatigue: five hours is short sleep.
4. Three of the six checks fail. The answer is not to fly.
5. Tell the instructor, rebook, and ask the aeromedical examiner or doctor before returning to flying while taking any medicine.
In the circuit an invented pilot sees the oil pressure fall, rather than the usual steady reading. Put the DECIDE steps in order for this event and say what a good Choose and Identify might be.
Show the answer
1. Detect: the oil pressure gauge is falling.
2. Estimate: it may mean engine failure soon; there is little time, and you are at circuit height near the aerodrome.
3. Choose: the outcome is a safe landing, soon, with a working engine if possible.
4. Identify: reduce power if appropriate, tell ATC (PAN PAN or MAYDAY, depending on how serious), and plan a close landing.
5. Do: fly the aeroplane first, then make the call.
6. Evaluate: is the pressure still falling, and is the landing still the best option? Re-loop if it changes.

7. Watch

A walk-through of decision-making models that goes with section 1. This video is American, so wording and some rules differ from European (ICAO/EASA) practice.

Open on YouTube if the player does not load. Not made by VectorEFB; check what you learn against your flying school’s material and your instructor.

More to watch

A second explanation of decision models from a different channel. Check what it says against your instructor’s advice, and note that it may follow American practice.

Open on YouTube if the player does not load. Not made by VectorEFB.

8. Check yourself

Five original practice questions. Answer them, press Check answers and read each explanation.

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