Common exam traps

Things students reliably get wrong in Human Performance:

• Breathing is driven by CO₂, not O₂. A rising carbon dioxide level speeds your breathing. This is why hyperventilation (over-breathing) is a lack of CO₂, not too little oxygen.
• Hypoxia first feels good. The early triad is euphoria, clumsiness, impaired judgement: you feel like you're doing a great job. Don't expect to "notice" it; oxygen on by 10,000 ft.
• Hypoxia vs hyperventilation. Treat hypoxia first (it's more urgent): above 10,000 ft try oxygen first; if no quick improvement, treat as hyperventilation (calm them, breathe into a bag). Below ≈10,000 ft, assume hyperventilation. Oxygen does not fix hyperventilation.
• Smoking ≈ +4,000–5,000 ft of hypoxia, and is anaemic hypoxia (CO hogs the haemoglobin), as is carbon monoxide poisoning.
• Carbon monoxide is odourless, but travels with smelly exhaust gases, often via the cabin heater from a cracked exhaust. Suspect it → heat off, fresh air on, land.
• Don't dive then fly: 12 h after compressed-air scuba; 24 h after deep/long dives. Snorkelling is fine.
• Ear/sinus problems are worse on the descent (air must flow up the Eustachian tube into the middle ear). Don't fly with a cold.
• Rods vs cones: cones = central, colour, detail, daylight; rods = peripheral, movement, night (no colour). At night look 10–20° off to the side of an object; the central vision has a night blind spot.
• Empty-field myopia: the resting eye focuses at 1–2 m, not infinity, so actively focus on a distant object to scan effectively.
• Day scan = short stops, ≈10° sectors, look directly. Night scan = slower, off-centre.
• Collision course = no relative movement (it just grows), so harder to see. Closing 1 nm at 600 kt = 6 seconds.
• Approach illusions, learn the direction: up-slope or narrow runway → feels high → you fly low (land short); down-slope or wide runway → feels low → you fly high. Haze → you're closer than it looks. Black-hole → feels high → flies dangerously low.
• Semicircular canals sense angular acceleration; the static organ senses g-direction. Neither senses steady motion, hence the leans (level feels banked after a long turn) and the somatogravic illusion (forward acceleration on take-off feels like a pitch-up → don't push the nose down). Trust the instruments, not the seat of your pants.
• Alcohol: 8 hours "bottle to throttle" minimum; ≈1 unit/hour to eliminate; can persist 30 h after heavy drinking; sleep doesn't speed it up.
• Stand-downs: blood donation 24 h; bone-marrow/general anaesthetic 48 h; local/dental anaesthetic ≈24 h; melatonin 12 h.
• Arousal is an inverted-U: too little = apathy/missed cues; optimum = best; too much = panic/tunnel vision. Eustress up to the peak, distress beyond it.
• Short-term memory = ≈7 items for ≈15 seconds → write clearances down and read them back; chunk to remember more.
• The brain is single-channel: one conscious decision at a time; that's why time-sharing and not interrupting checklists matter.
• Confirmation bias / mind-set: you hear "cleared to land" when told "go around." Re-assess; don't lock on.
• The 5 hazardous attitudes (A-I-I-M-R): Anti-authority ("rules don't apply") → follow the rules; Impulsivity ("do it now") → not so fast, think; Invulnerability ("won't happen to me") → it could happen to me; Macho ("watch this") → taking chances is foolish; Resignation ("what's the use") → I'm not helpless.
• TEM order = Avoid → Trap → Mitigate (Anticipation, Recognition, Recovery). Avoid is the highest/best layer.
• SA = Notice, Understand, Think Ahead (NUTA). Most accidents come from low SA, not bad decisions.
• Swiss cheese: no single cause; holes line up across organisation, supervision, preconditions, the unsafe act. You control the last two, so be the last barrier.
• Risky shift: a group decides more riskily than individuals, so as single-pilot PIC, don't get talked into it.
• West is best, east is a beast for jet lag; performance bottoms out at 04:00–06:00 with the body-temperature low.