Stress

Definition (Selye)

Hans Selye (The Stress of Life, 1956) defined stress as the body's unspecific response to any demand. The General Adaptation Syndrome (GAS) has three stages:

Alarm — sympathetic activation, adrenaline, cortisol. Heart rate ↑, breathing ↑, pupils wide. Mobilises performance short-term.
Resistance — under prolonged demand; compensation, but reserves deplete.
Exhaustion — collapse of compensation; health and cognitive deficits.

Acute vs chronic stress

Acute stress (e.g. engine failure): brief, high activation. Benefits from Yerkes-Dodson law (1908): performance rises up to an optimal arousal level, then falls due to tunnel thinking, narrowing perception, motor tension.

Chronic stress (work, relationship, money worries, training pressure): no recovery phases; working memory stays loaded, sleep quality drops, openness to stimuli declines.

Effect on cockpit performance

Stress affects practically all cognitive functions in the cockpit:

Function	Effect under stress
Attention	Focus narrowing, tunnel vision
Concentration	reduced
Reaction	increased reaction time
Memory	forgetting standard steps
Vigilance	reduced, especially in monotony
Cautious behaviour	reduced — readiness for risky decisions ↑
Uptake of new information	reduced — old plans clung to, new cues ignored

→ With rising stress load during a flight, one is less likely to take in new information — e.g. weather changes or ATC route changes are missed.

Workload and performance — Yerkes-Dodson extended

With rising workload, performance first rises, then falls:

code

Performance
    ↑
    │       ╭─╮
    │      ╱   ╲
    │     ╱     ╲
    │    ╱       ╲
    │   ╱         ╲___
    │__╱
    └─────────────────► Workload
       low   optimal   overload

Optimum is at moderate workload — too little (underload, cruise on autopilot) and too much (overload, bad-weather approach with radio congestion) reduce performance.

Overloaded pilot symptoms

An overloaded pilot shows a characteristic symptom constellation. Recognition — including by other crew or instructor — is decisive to stop impending escalation:

Cognitive symptoms

Thinking barrier (mind blank) — pilot suddenly doesn't know what to do.
Confusion — time sequence or order unclear.
Channelized attention — fixated on a single problem, blocks out everything else.

Emotional symptoms

Resignation — "I can't do this any more".
Frustration.
Anger / rage — outburst at co-pilot, ATC, passenger.

Motor symptoms

Reduction of motor coordination — control inputs rough, imprecise.
Hasty movements — switches operated too fast.

Speech symptoms

Excited voice — higher pitch, strained.
Hasty speaking — radio calls rushed, hard to understand.
Speech errors — wrong phrases, slips.

→ Other crew members (instructor, co-pilot) should recognise these symptoms and intervene: actively reduce workload, take over, offer break ("I have control, take a deep breath").

Stress from unusual flight manoeuvres

Unusual flight manoeuvres are an independent source of stress, even when objectively safe:

Situation	Typical reaction
Stall training (first time)	Nervousness, pulse rise
Steep turn > 45° bank	Feeling of loss of control
Slow flight near stall	Attentional tension
Crosswind landing in strong wind	Concentration problems
First solo flight	Nervousness, sometimes nausea

→ Symptoms: nervousness, feeling unwell, declining concentration, sweaty hands. This is normal and decreases with experience.

Show-off risk — stress from observers

Some pilots tend to take unnecessary risks when observed and admired:

Low flight in front of friends or family.
Aerobatic manoeuvres in front of spectators (against regulation).
Beat-up of home airfield in front of colleagues.
Overly fast approaches for "demonstration".

Mechanism: the brain perceives observation as reward, reduces risk assessment. Macho and invulnerability (see [[aufmerksamkeit-workload-situational-awareness]]) amplify this.

→ Awareness of the phenomenon is the first step to avoidance. Pilot should internally ask: "Would I do this manoeuvre without an audience?"

Coping

Problem-focused — address the stressor (e.g. alternate airfield instead of landing in bad weather). Emotion-focused — regulate own reaction: deliberate diaphragmatic breathing (4-7-8), pause, "aviate-navigate-communicate" prioritisation.

Under mental overload — strategy

Concrete 3-step strategy under workload overload:

Use available resources — involve co-pilot, instructor, ATC ("standby", workload pause).
Tasks sequentially, not in parallel — one after another, not all at once.
Prioritisation "aviate, navigate, communicate" — if only one task fits: fly the aircraft.

ICAO Doc 9683 recommends stress-management training as part of HPL education. Practical for PPL:

Pre-flight: IMSAFE-S (see [[flugtauglichkeits-selbstcheck-imsafe]]).
In-flight: when overwhelmed, reduce workload (leave climb, straight and level, inform ATC, re-brief).
Emergency: ICAO Doc 4444 §15 / FAA-H-8083-25 — Mayday/Pan, involve ATC.

See [[aufmerksamkeit-workload-situational-awareness]] (workload, hazardous attitudes), [[ernaehrung-fluessigkeit-rauchen]] (hypoglycaemia amplifies stress), [[raeumliche-desorientierung]] (acute stress promotes SD).