Brunei DCA CPL(A) Human Performance cheat sheet

Shelton's SHELL model: Software (procedures, rules), Hardware (aircraft, equipment), Environment, Liveware (humans) - mismatches at the Liveware boundary are the main error source.

Reason's Swiss cheese model: latent conditions (organisational) align with active failures (front-line) to breach defences; each layer has holes that shift with time.

ICAO HF training is competence-based: knowledge, skills and attitudes are assessed, not just factual recall.

Human information processing: sensation → perception → decision → response; bottlenecks occur at attention (limited capacity) and working memory (about 4 chunks, seconds duration).

Attention is selective and can be divided only at cost; vigilance decrements appear within 30 minutes of monotonous monitoring.

Perception is constructive: expectation and prior experience shape interpretation, which is why ambiguous cues are misread under high workload.

Skill acquisition stages: cognitive (effortful, error-prone), associative (practice, fewer errors), autonomous (automatic, fast but hard to unlearn).

Behaviour is a function of the person and the environment (Lewin); pilot performance is therefore context-dependent, not fixed.

Composition of dry air: 78% nitrogen, 21% oxygen, 1% other gases; water vapour varies and reduces partial pressure of oxygen.

Dalton's law: total pressure = sum of partial pressures; alveolar PO2 falls with altitude even though oxygen percentage stays 21%.

Boyle's law: at constant temperature, gas volume is inversely proportional to pressure - gas expands on ascent and contracts on descent (basis of barotrauma and DCS).

Henry's law: dissolved gas quantity is proportional to partial pressure - the basis of nitrogen loading and decompression sickness.

Gaseous exchange occurs by diffusion down partial-pressure gradients in the alveoli and tissues.

At 10,000 ft cabin altitude, alveolar PO2 is roughly 60 mmHg and arterial saturation is about 87-90% in a healthy resting pilot.

Respiratory drive is controlled by CO2 (central chemoreceptors) more than by oxygen; hypoxic drive becomes significant only at very low PaO2.

Core body temperature is regulated near 37 °C; cold stress impairs manual dexterity and judgement before shivering is obvious.

Central nervous system = brain and spinal cord; peripheral nervous system = somatic (voluntary) and autonomic (sympathetic/parasympathetic).

Visual acuity is greatest at the fovea (cones, colour, day vision); rods dominate peripherally, are motion- and dim-light sensitive but colour-blind.

Dark adaptation takes about 30 minutes; exposure to bright white light resets it - red light preserves night vision.

Empty-field myopia: focusing on a featureless sky or sea causes the eye to rest at about 1 m, making distant aircraft appear closer.

Vestibular system: semicircular canals detect angular acceleration (head rotation); otolith organs (utricle, saccule) detect linear acceleration and gravity.

Somatogyral illusion: after sustained rotation, the canals' endolymph lags and the pilot falsely perceives rotation in the opposite direction.

Somatogravic illusion: linear acceleration is misperceived as pitch - acceleration feels like a climb, deceleration like a descent.

Hearing loss is greatest at high frequencies; noise-induced loss is cumulative and permanent, while temporary threshold shift recovers in hours.

The eye is the dominant spatial sense in flight; when visual cues conflict with vestibular cues, vision is normally the more reliable reference.

Hypoxic hypoxia = reduced alveolar PO2 (altitude); hypemic = reduced oxygen-carrying capacity (anaemia, CO); stagnant = poor circulation; histotoxic = cells cannot use oxygen (cyanide, alcohol).

Time of useful consciousness at 25,000 ft is roughly 3-5 minutes; at 35,000 ft about 30-60 seconds; at 40,000 ft 15-20 seconds.

Early hypoxia signs: euphoria, impaired judgement, poor coordination, cyanosis, tingling, light-headedness; judgement loss precedes self-recognition.

Hyperventilation lowers PaCO2 (hypocapnia), causing cerebral vasoconstriction, dizziness, tingling of fingers and lips, and carpopedal spasm.

Hyperventilation and hypoxia share symptoms; the safe rule is to assume hypoxia, use 100% oxygen, and control breathing rate.

Cabin pressurisation maintains a cabin altitude typically at or below 8,000 ft; pressurisation failure requires oxygen and descent.

Carbon monoxide binds haemoglobin about 200-250 times more strongly than oxygen, producing headache and confusion without cyanosis (cherry-red skin is a late sign).

Smoking raises carboxyhaemoglobin and effectively lowers the pilot's ceiling for hypoxia onset.

Decompression sickness arises from nitrogen bubbles forming in tissues and blood when ambient pressure falls too fast after a high-pressure exposure.

Type I DCS: joint and limb pain ('bends'), skin itching or mottling. Type II DCS: neurological, respiratory (chokes) or cardiovascular involvement - more serious.

Prevention: pre-breathing 100% oxygen before high-altitude flight, limiting exposure time, avoiding flying after diving, and slow ascent.

Flying after diving guidance: allow at least 12-24 hours after a no-decompression dive, longer after decompression or repetitive dives; follow the operator's published table.

Barotrauma of the ear: middle-ear squeeze on descent if the Eustachian tube cannot equalise; symptoms include pain, muffled hearing and possible rupture.

Equalisation methods: Valsalva (gentle), Toynbee (swallow with nose pinched), yawning, chewing; never force pressure with a heavy Valsalva during a cold.

Sinus barotrauma presents as severe facial pain on descent; dental barotrauma (barodontalgia) occurs in teeth with trapped gas or decay.

Treatment of DCS is 100% oxygen, descent to a lower altitude, immobilise, and urgent hyperbaric recompression; do not continue the flight.

+Gz is head-to-foot acceleration (pushes blood away from the brain); -Gz is foot-to-head; +Gx is chest-to-back (eyeballs-in).

G tolerance is reduced by fatigue, dehydration, heat, hypoxia, illness, and lack of recent exposure; it is increased by physical conditioning and anti-G straining.

Grey-out (loss of peripheral vision) precedes black-out (loss of central vision) and then G-LOC at high sustained +Gz.

The anti-G straining manoeuvre (AGSM) combines a leg, abdominal and gluteal muscle tensing with a forced exhalation cycle to raise blood pressure.

Anti-G suits inflate over the legs and abdomen to limit blood pooling; they supplement, not replace, the AGSM.

A-LOC (almost loss of consciousness) can occur without full G-LOC and produces disorientation and amnesia.

-Gz exposure causes facial congestion, red-out and headache; +Gx exposure is better tolerated and is the usual seated launch/re-entry orientation.

Recovery from G-LOC may include a period of confusion and involuntary movements; the pilot should not assume immediate competence on regaining consciousness.

Spatial disorientation: failure to perceive correctly position, motion or attitude relative to the earth; unrecognised SD is a leading cause of fatal accidents.

Types: unrecognised (the pilot is unaware), recognised (the pilot knows something is wrong but cannot resolve it), and incapacitating.

Leans occur after an undetected bank is corrected; the false sensation of banking in the opposite direction can prompt a wrong correction.

The graveyard spiral follows a prolonged unnoticed bank with loss of altitude and increasing bank; rely on instruments, not sensation.

Coriolis illusion is triggered by a head movement during a sustained turn, producing violent tumbling sensations; avoid head movements in turns.

Motion sickness is caused by sensory conflict between visual, vestibular and somatosensory inputs; it is worsened by turbulence, heat and anxiety.

Prevention of motion sickness: fresh air, minimise head movements, focus on distant or instrument references, avoid heavy meals; medication must be approved and tested for side effects.

The only reliable remedy for SD is to fly on instruments, cross-check, and trust the attitude indicator.

Fatigue is a physiological state of reduced performance from prolonged activity, sleep loss or circadian disruption; it differs from tiredness, which is relieved by rest.

Sleep stages: NREM (N1, N2, N3 slow-wave) and REM; slow-wave sleep restores physical function, REM supports memory and learning.

A normal adult needs 7-9 hours; cumulative sleep debt of 2 hours per night degrades performance comparably to a blood alcohol level near the legal limit.

Circadian rhythm is a roughly 24-hour cycle entrained by light; the low points are around 02:00-06:00 and 14:00-16:00, when alertness is lowest.

Circadian dysrhythmia (jet lag) occurs after rapid time-zone crossing; eastward travel is usually harder because the body clock must advance.

Sleep inertia is the temporary grogginess after waking; it is worse after waking from slow-wave sleep and impairs performance for 15-30 minutes.

Napping 20-30 minutes restores alertness without significant sleep inertia; longer naps risk deeper sleep and grogginess.

Caffeine has a half-life of about 5-6 hours and can delay sleep; alcohol reduces sleep quality and REM sleep even though it causes drowsiness.

Yerkes-Dodson law: performance rises with arousal to an optimum and then falls; the optimum narrows as task complexity increases.

Stressors are physical (noise, heat, vibration), physiological (fatigue, illness) and psychological (deadlines, interpersonal conflict).

Acute stress produces sympathetic activation (adrenaline, increased heart rate and breathing); chronic stress impairs memory, sleep and immunity.

Defence mechanisms such as denial and displacement can mask stress; they are normal but can distort decision-making.

Workload is the relationship between task demands and the operator's capacity; overload causes tunnelling, omission and error; underload causes boredom and vigilance failure.

Crew resource management reduces workload through task sharing, prioritisation and explicit verbal callouts.

Recognising stress in oneself and others (irritability, fixation, withdrawal, rapid speech) is the first step to managing it.

Breathing control and structured checklists are practical methods to lower arousal and restore workload capacity in flight.

Error types: slips (correct intention, wrong execution), lapses (forgotten action), mistakes (wrong intention), and violations (deliberate deviation).

Errors are consequences of normal cognitive limits, not moral failings; blame-based reporting suppresses safety information.

TEM model: threats (external, crew, aircraft) are anticipated and avoided; errors are trapped and mitigated; undesired aircraft states are recovered.

CRM core skills: communication, leadership and followership, situational awareness, decision-making, workload management and team building.

Effective communication is closed-loop: sender states the message, receiver repeats and confirms it.

Assertiveness and the 'two-challenge rule' allow any crew member to question a decision and require a response.

Threat and error management is not error-free operation; it is about managing the consequences of inevitable error.

Just culture: honest mistakes are supported, reckless behaviour is sanctioned, and reporting is protected.

Decision-making models: DECIDE (Detect, Estimate, Choose, Identify, Do, Evaluate) and the OODA loop (Observe, Orient, Decide, Act).

Situational awareness has three levels: perception of elements, comprehension of meaning, and projection of future states.

Loss of SA is often preceded by fixation, ambiguity, unmet expectations or a failure to monitor; checklists and cross-checks restore it.

Automation: monitoring failures ('automation complacency'), mode confusion and skill degradation are common; pilots must remain the final authority.

Automation bias is over-trust in automation; it is countered by active monitoring and understanding the system's logic.

Health and fitness: self-declaration of fitness to fly, alcohol minimum of 8 hours and no residual effect, and medication only if approved.

IMSAFE checklist: Illness, Medication, Stress, Alcohol, Fatigue, Emotion/Eating.

Prescription and over-the-counter drugs can impair performance; the pilot must confirm acceptability with the authority and test the effect before flying.

Decision quality is improved by generating more than one option and by consulting the crew before committing to a plan.

Aeronautical decision making includes recognising hazardous attitudes: anti-authority, impulsivity, invulnerability, machismo and resignation.

The '3P' model - Perceive, Process, Perform - is a practical in-flight decision cycle.

Situational awareness is degraded by high workload, fatigue, distractions and fixation; it is restored by cross-checking instruments and verbalising the situation.

Automation should be used within its design envelope; the pilot must understand what the automation is doing and why.

Fitness to fly is a continuous judgement, not a one-off medical certificate: symptoms, medication, sleep and stress all affect it.

Dehydration of 2% body mass impairs cognitive performance; cabin air is dry, so fluid intake is a performance tool.

Post-incident stress and cumulative fatigue should be reported and managed through the operator's support programme.

+Gz tolerance in a relaxed, unprotected pilot is roughly 4-5 G; with AGSM and G-suit it rises to about 8-9 G.

G-LOC occurs when cerebral blood pressure falls below the level needed for retinal and brain perfusion; duration of unconsciousness can be 15-30 seconds or more.

Rapid decompression at altitude produces a sudden drop in cabin pressure, fogging from water vapour, and a temperature drop; oxygen masks deploy automatically.

Time of useful consciousness after rapid decompression is shorter than after slow decompression at the same altitude.

Barotrauma risk is highest when a cold or sinus congestion blocks the Eustachian tube or sinus ostia; do not fly with active congestion.

DCS symptoms can be delayed for hours after exposure; any suspected DCS after altitude exposure requires grounding and medical assessment.

Ear block on descent is treated by stopping the descent, equalising, and if necessary climbing back to reduce the pressure differential.

Hypoxia and DCS can coexist after rapid decompression; treat with 100% oxygen and descent first.

Black-hole approach: at night, with no ground reference, the pilot may fly a lower-than-normal approach because the runway appears higher.

Autokinesis: a stationary light in a dark sky appears to move - do not chase it; use instruments.

False horizon illusions occur with sloping cloud or terrain; cross-check the attitude indicator.

Size-distance illusion: a wider or narrower runway than expected causes a high or low approach respectively.

Somatosensory illusions: seat-of-the-pants sensations are unreliable in turbulence and in sustained turns.

Noise exposure above 85 dB(A) over 8 hours risks hearing damage; cockpit noise is often higher and hearing protection is recommended.

Hearing loss reduces the ability to detect warning tones and radio calls; a hearing test is part of the medical.

Vestibular illusions are most dangerous in low-visibility or night flight without a visible horizon; instrument reference is the defence.

Hypoxia onset is insidious: the pilot may feel euphoric and capable while judgement and coordination are already impaired.

Signs: cyanosis, rapid breathing, headache, tingling, visual disturbance, confusion, and eventually unconsciousness.

Response: 100% oxygen, descend to a lower altitude, and land as soon as practicable; do not continue the flight.

Hyperventilation: rapid deep breathing lowers CO2, causing dizziness, tingling, chest tightness and carpopedal spasm.

Differentiate by using oxygen and slowing the breathing rate; if symptoms resolve with oxygen, hypoxia was likely.

Cabin altitude above 10,000 ft requires supplemental oxygen for the crew under most regulations; check the operator's rules.

Smokers and anaemic pilots have reduced oxygen-carrying capacity and reach hypoxia sooner.

Pulse oximetry can support suspicion of hypoxia but must not replace clinical judgement in flight.

DCS risk rises with the depth and duration of the pressure exposure, the rate of ascent, and repeated exposures.

Pre-breathing 100% oxygen for at least 30 minutes before high-altitude exposure reduces nitrogen loading.

Flying after diving: no-decompression dives require a minimum surface interval before flight; the exact interval depends on the dive profile and the operator's table.

Type II DCS is a medical emergency; treat with oxygen, keep the pilot lying down, and arrange hyperbaric treatment urgently.

Middle-ear barotrauma: pain, hearing loss and tinnitus on descent; equalise early and often, and do not force.

Sinus barotrauma: severe pain over the affected sinus on descent; treat with decongestants only under medical advice.

Barodontalgia: tooth pain from trapped gas in a cavity; dental review before flight is the preventive measure.

Never fly with an active upper respiratory infection if equalisation is difficult.

G-induced loss of consciousness is preceded by grey-out and black-out; the pilot should initiate AGSM early.

Anti-G straining manoeuvre: tense legs, abdomen and glutes, and perform a forced exhalation against a partially closed glottis.

Spatial disorientation is most likely when visual cues are degraded (night, cloud, featureless terrain) and during sustained turns.

The leans: an undetected bank is corrected, and the false sensation of banking the other way can cause a wrong control input.

Coriolis illusion: avoid head movements during sustained turns; if it occurs, fixate on instruments and minimise motion.

The attitude indicator is the primary reference in instrument conditions; trust it over sensations.

Motion sickness prevention: fresh air, avoid head movements, focus on distant references, and use approved medication only after testing.

Disorientation training and simulator exposure improve recognition and recovery.

Fatigue risk management uses sleep, duty time, circadian timing and workload as inputs.

The circadian low (about 02:00-06:00) coincides with the greatest sleepiness and error risk on night duty.

Sleep debt accumulates and is only repaid by sleep, not by caffeine or motivation.

A 20-30 minute nap improves alertness; longer naps risk sleep inertia.

Caffeine half-life is about 5-6 hours; avoid it within 6 hours of planned sleep.

Alcohol reduces sleep quality and REM; it is not a sleep aid and must not be used before flight.

Jet lag: eastward travel advances the clock and is usually harder; light exposure and scheduled sleep help adaptation.

Report fatigue through the operator's fatigue reporting system rather than flying impaired.

Optimal arousal is task-dependent: complex tasks need lower arousal than simple ones (Yerkes-Dodson).

Workload management tools: prioritise, delegate, use checklists, and shed non-essential tasks.

Overload signs: tunnelling, omission, fixation, and degraded communication.

Underload signs: boredom, complacency and vigilance failure during cruise or monitoring.

Stress in the cockpit can be reduced by structured briefing, clear roles and closed-loop communication.

Recognise stress in oneself: irritability, rapid speech, fixation and withdrawal are early signs.

Controlled breathing and short breaks restore arousal to the optimum.

Chronic stress and life events should be declared through the operator's support channels.

Threats are external events that increase complexity; errors are crew actions that deviate from intention or expectation.

TEM loop: anticipate and avoid threats, trap and mitigate errors, recover from undesired aircraft states.

Closed-loop communication: state, repeat, confirm.

Two-challenge rule: any crew member may challenge a decision and must receive a response.

Leadership is situational: the captain leads, but the most informed crew member may take the lead for a specific task.

Just culture distinguishes human error from reckless behaviour and protects reporting.

Briefings should include threats, roles, and the plan for contingencies.

Monitoring is an active task: verify mode changes and flight path against the plan.

DECIDE model: Detect the change, Estimate its effect, Choose a desirable outcome, Identify actions, Do the best action, Evaluate the result.

Situational awareness levels: perception, comprehension, projection; loss of any level degrades the others.

Automation complacency: reduced monitoring when automation is reliable; counter by active cross-checking.

Mode confusion: the automation is in a mode the pilot did not intend; verify annunciations after every mode change.

Skill degradation from automation dependency is countered by manual flying practice.

Fitness to fly: IMSAFE (Illness, Medication, Stress, Alcohol, Fatigue, Emotion/Eating).

Dehydration and poor nutrition degrade cognitive performance; plan fluid and food intake on long duty.

Post-incident stress should be managed through the operator's peer support and EAP programmes.

Self-declare fitness before every flight; a valid medical certificate does not guarantee fitness on the day.

Alcohol: minimum 8 hours between last drink and flight, and no residual impairment; check the operator's stricter rule.

Medication: only fly with medication approved by the authority; test the effect on the ground first.

Common cold: do not fly with active congestion if equalisation is difficult.

Vaccinations and travel medicine can affect fitness; allow for side effects before duty.

Vision and hearing changes should be reported to the AME; corrective lenses must be worn as endorsed.

Mental health: stress, anxiety and depression are treatable; declare and seek support rather than self-medicate.

Fatigue, dehydration and poor diet are performance limiters that can be managed before flight.

Cabin altitude is normally maintained at or below 8,000 ft; higher cabin altitudes increase hypoxia risk.

Supplemental oxygen is required above specified cabin altitudes; the exact rule depends on the operator's approval.

Oxygen masks must be within reach and checked before flight; quick-donning masks are required for high-altitude operations.

Rapid decompression causes fogging, a temperature drop and noise; masks deploy automatically on many aircraft.

Time of useful consciousness decreases rapidly above 25,000 ft.

Carbon monoxide can enter the cabin from heaters or engine bleed; suspect it with headache and confusion without cyanosis.

Smoke and fumes: use oxygen, land as soon as practicable, and follow the operator's checklist.

Cabin humidity is low; dehydration impairs performance and is managed by drinking water.

Rods are more sensitive in dim light but do not detect colour; cones provide colour and high acuity in daylight.

Dark adaptation takes about 30 minutes; bright light resets it.

Empty-field myopia causes distant objects to appear closer in a featureless sky.

Autokinesis: a stationary light appears to move in a dark sky.

Semicircular canals detect angular acceleration; otolith organs detect linear acceleration and gravity.

Coriolis illusion follows a head movement in a sustained turn.

Somatogravic illusion: acceleration feels like a climb.

Noise-induced hearing loss is cumulative and permanent; hearing protection is recommended in noisy cockpits.

Alveolar PO2 falls with altitude even though oxygen percentage remains 21%.

Time of useful consciousness at 25,000 ft is about 3-5 minutes; at 35,000 ft about 30-60 seconds.

Hypoxia signs: euphoria, impaired judgement, cyanosis, tingling and visual disturbance.

Hyperventilation lowers CO2 and causes dizziness, tingling and carpopedal spasm.

Differentiate by giving 100% oxygen and slowing breathing.

Smoking and anaemia reduce oxygen-carrying capacity and hasten hypoxia.

Carbon monoxide poisoning produces headache and confusion without cyanosis.

Treat suspected hypoxia with oxygen and descent.

Boyle's law explains gas expansion on ascent and contraction on descent.

Henry's law explains nitrogen loading and DCS.

Type I DCS: joint pain and skin symptoms; Type II DCS: neurological or respiratory involvement.

Pre-breathing oxygen reduces nitrogen loading before high-altitude exposure.

Flying after diving requires a surface interval; follow the operator's table.

Middle-ear squeeze on descent is prevented by early and frequent equalisation.

Sinus and dental barotrauma occur with trapped gas.

Treat suspected DCS with oxygen, immobilisation and urgent hyperbaric referral.

+Gz pushes blood away from the brain; grey-out precedes black-out and G-LOC.

AGSM and anti-G suits raise G tolerance.

G tolerance is reduced by fatigue, dehydration and heat.

Spatial disorientation is most likely without a visible horizon.

The leans and graveyard spiral are classic illusions.

Coriolis illusion follows head movement in a turn.

Trust the attitude indicator in instrument conditions.

Motion sickness is caused by sensory conflict; prevention includes fresh air and minimising head movements.

Sleep stages: NREM (N1-N3) and REM; slow-wave sleep restores physical function.

Adults need 7-9 hours of sleep; sleep debt degrades performance.

Circadian low points are around 02:00-06:00 and 14:00-16:00.

Jet lag is worse eastward because the clock must advance.

A 20-30 minute nap improves alertness without sleep inertia.

Caffeine half-life is about 5-6 hours.

Alcohol reduces sleep quality and REM.

Report fatigue rather than flying impaired.

Yerkes-Dodson: performance peaks at moderate arousal and falls at high arousal.

Stressors are physical, physiological and psychological.

Acute stress activates the sympathetic nervous system.

Overload causes tunnelling and omission; underload causes vigilance failure.

Workload management uses prioritisation, delegation and checklists.

Recognise stress signs in oneself and others.

Controlled breathing lowers arousal.

Chronic stress should be declared and managed through support programmes.

Error types: slips, lapses, mistakes and violations.

Errors are normal cognitive consequences, not moral failings.

TEM: anticipate threats, trap errors, recover from undesired aircraft states.

CRM skills: communication, leadership, situational awareness, decision-making and teamwork.

Closed-loop communication confirms understanding.

The two-challenge rule allows any crew member to question a decision.

Just culture protects reporting of honest mistakes.

Briefings should include threats, roles and contingencies.

DECIDE and OODA are structured decision models.

Situational awareness levels: perception, comprehension, projection.

Loss of SA is preceded by fixation, ambiguity or unmet expectations.

Automation complacency and mode confusion are common automation errors.

Automation bias is over-trust in automation; counter with active monitoring.

IMSAFE is a fitness-to-fly checklist.

Dehydration impairs cognitive performance.

Post-incident stress should be managed through support programmes.

Self-declare fitness before every flight.

Alcohol: minimum 8 hours and no residual impairment; check the operator's rule.

Only fly with approved medication and test the effect on the ground.

Do not fly with active congestion if equalisation is difficult.

Report vision and hearing changes to the AME.

Mental health conditions are treatable; declare and seek support.

Fatigue, dehydration and poor diet are performance limiters.

Vaccinations and travel medicine can affect fitness; allow for side effects.