Practice: Human Factors

What do the practice questions keep testing?

Revision map

The whole syllabus in four branches. Tap + to open a box, tap any box for detail.

• Human Factors revision four branches Practice-question revision of human factors, grouped into the body, the senses, the mind, and crew and automation.
  • Body air, pressure, G Revision on air and breathing, hypoxia, hyperventilation, decompression, the ears and G-forces.
    • Air and breathing Air is 78% nitrogen and 21% oxygen; oxygen and carbon dioxide are the gases that matter to the body, and blood CO2 sets breathing.
      • N2 78%, O2 21%, CO2 0.03% The oxygen percentage stays the same; its partial pressure falls with altitude.
      • Breathing set by blood CO2 The rate and depth of breathing are regulated mainly by the concentration of carbon dioxide in the blood.
    • Hypoxia judgment goes first Lack of oxygen. Its most dangerous symptoms are euphoria and impaired judgment, so the pilot may not recognise it.
      • Worst symptom: impaired judgment The pilot cannot recognise his own symptoms.
      • Night vision hit from 5,000 ft Hypoxia affects night vision from as low as 5,000 ft.
      • Types named: stagnant, anaemic This chapter names stagnant hypoxia and anaemic hypoxia as types of hypoxia.
    • Hyperventilation breathe into a bag Raises blood CO2. Tingling in arms or legs is shared with hypoxia.
    • Decompression and ears Decompression releases nitrogen bubbles in the body, and a cold makes the middle ear hard to equalise in a rapid descent.
      • Bends: most common DCS symptom Joint pain. The bends are the most frequent decompression sickness symptom after a decompression in airline operation.
      • Pronounced from 7,000 to 35,000 ft Decompression sickness is most likely when cabin pressure is lost and the cabin goes from 7,000 ft to 35,000 ft.
      • Middle ear: colds, rapid descents Swollen tissue near the Eustachian tube makes equalising hard.
    • G-forces see the G lessons Pulling positive G: grey-out from about +3 G and tunnel vision from about +3.5 G. Pushing forward hard right after recovering from a steep dive: red-out.
  • Senses vision and balance Revision on night vision, empty field myopia, autokinesis, the narrow-runway illusion and disorientation.
    • Night vision rods, about 30 min to adapt Night vision depends on the rods, and the eye needs about 30 minutes to adapt fully to the dark.
    • Empty field myopia no distant focal point Caused by a lack of distant focal points to look at.
    • Autokinesis add references Use extra references inside or outside the cockpit with peripheral vision.
    • Narrow runway feel higher, risk of undershoot A narrower runway makes the pilot feel higher than he is, so he may fly a flatter approach and undershoot.
    • Disorientation conflict, distrust of instruments Most likely when the brain gets mixed messages and the pilot does not trust the instruments.
  • Mind memory, stress, rhythm Revision on memory and learning, stress, arousal, fatigue, the body clock and sleep.
    • Memory and learning Short-term memory holds information for about 20 seconds, long-term knowledge should be pre-activated, and processing starts with the senses.
      • Short-term memory: about 20 s Information is stored in short-term memory for approximately 20 seconds.
      • Pre-activate long-term knowledge It helps to 'warm up' what you know in long-term memory before you need it, so it is ready.
      • Processing starts with the senses Information processing starts with the senses picking something up.
      • Learning motivation, practice, feedback Learning to fly takes motivation, attention, watching, practice and someone correcting you.
    • Stress How stress is experienced depends on how the individual interprets the situation; stressors accumulate and raise the likelihood of exhaustion.
      • Moderate stress may help Stressors accumulate and raise the chance of exhaustion.
      • Acute stress: mobilisation beyond willpower Acute stress quickly mobilises the resources needed to cope with the stressors.
      • Signs sweating, flushing, wide pupils Sweating, a red face, wide pupils and quick breathing.
    • High arousal narrows attention In a complex task, being very keyed up shrinks how much you can pay attention to.
    • Fatigue: fewer matters handled Tiredness reduces the ability to manage several matters at once.
    • Body clock and sleep Time-zone changes disturb the biological clock, which resynchronises only slowly; sleep stages and timing affect rest.
      • Resync 1 to 1.5 h a day In a new time zone the body's rhythms resynchronise at about 1 to 1.5 hours a day.
      • Sleep length set by body-clock timing How long you sleep depends mostly on where you are in your body clock when you go to sleep.
      • Paradoxical sleep: rapid eye movements In REM (paradoxical) sleep, the eyes move quickly under the lids.
      • Day 3 of a layover: local time On the 3rd day of a 4-day layover, local time (LT) is the time measure relevant to your circadian rhythm.
  • Crew and automation SHEL, CRM, machines Revision on the SHEL model, CRM, the authority gradient, crew co-operation and the drawbacks of automation.
    • SHEL model four elements A model of four elements: software, hardware, environment and liveware.
      • Software The S of the SHEL model, one of its four elements.
      • Hardware The H of the SHEL model. A Liveware-Hardware mismatch from poor cockpit design causes stress.
      • Environment The E of the SHEL model, one of its four elements.
      • Liveware Poor cockpit design is a Liveware-Hardware stress.
    • CRM aim attitudes and relationships CRM training tries to make crews work better by improving their attitude to flight safety and how they handle working with each other.
    • Authority gradient captain and first officer The authority relationship between the captain and the first officer.
    • Co-operation needs 3 things Crew co-operation is optimised by a shared common task, confidence in each other's capability and a precise definition of each member's role.
      • A shared task The crew share a common task.
      • Trust in each other Each crew member has confidence in the others' capability.
      • Clear roles The functions of each crew member's role are precisely defined.
    • Automation moves error, adds workload Introducing automation generally relocates the potential for error and increases workload.
      • Crew out of the loop High cockpit automation can reduce the crew's attention, leaving them out of the loop.
      • Manual skill fades A drawback of automation is less manual control of the aircraft.
      • More programming slips One downside of automation: more slips when typing or setting up the automatic systems.
      • Error relocated, workload up Automation does not remove error; it generally moves the potential for error elsewhere and increases workload.

Takeaway: Hypoxia steals judgment first, the senses can lie, arousal narrows attention, and automation moves error rather than removing it.

Why is there less oxygen if it is still 21%?

Thin air

Each column is the air pressing on you. Its height is the total pressure.

Takeaway: The mix never changes, but the total pressure falls, so oxygen's partial pressure falls with it. That is Dalton's law, and it explains altitude hypoxia.

Hypoxia or hyperventilation: how do you tell?

Hypoxia or hyper?

Same tingling, different cause, opposite treatment. Read across each row.

This lesson is part of the Core plan. See plans

What do G, practice and symptoms tell you?

Revision toys

Three views: G effects, skill phases and the four symptom groups.

This lesson is part of the Core plan. See plans

What happens to your view as G builds?

G and vision

Three views of the same horizon as positive G rises from left to right.

This lesson is part of the Core plan. See plans

How does a skill become automatic?

Skill phases

Three phases of a motor programme, from first lesson to experienced captain.

This lesson is part of the Core plan. See plans

Practice set: the body

Body

Twelve practice questions on air, pressure, blood and G.

This lesson is part of the Exam-Ready plan. See plans

Practice set: senses and illusions

Senses

Twelve practice questions on eyes, ears and illusions.

This lesson is part of the Exam-Ready plan. See plans

Practice set: the mind

Mind

Twelve practice questions on memory, arousal, stress and learning.

This lesson is part of the Exam-Ready plan. See plans

Practice set: crew and automation

Work

Twelve practice questions on crews, automation and the body clock.

This lesson is part of the Exam-Ready plan. See plans

Hypoxia, hyperventilation, DCS or CO?

Sort the symptoms

Read each case and press the stamp that applies.

This lesson is part of the Exam-Ready plan. See plans

Numbers to know

Numbers

The figures these practice questions use.

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Pairs that catch students out

Don't mix up

Read both sides, then the line that tells them apart.

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Test yourself

Five quick questions from this chapter.

This lesson is part of the Core plan. See plans