Human Performance Flashcards
SHELL model
S - software (manuals, procedures)
H - hardware (equipment)
E - environment
L - Liveware (other people)
L - Liveware (pilot)
Pilot liveware is central to the other 4.
2 components of liveware considerations
- Psychological
- Physiological
Nervous system components
Central - Brain & spinal cord
Peripheral - Networks of nerves and ganglia
Division of peripheral nervous system
Autonomic: Organs and non-voluntary functions such as heart beat, sweating, digestion.
Sensory-somatic: Everything under voluntary control
Cardiovascular system components
Heart
Blood vessels
Blood
Types of blood vessel
Arteries: Thick, carry blood from heart
Veins: Carry blood back to heart
Capillaries: Smaller vessels joining arteries to veins, travelling in networks through organs.
Two parts of blood circulation
Systemic circulation: From left side of heart, through organs, back to right side of heart.
Pulmonary circulation: From right side of heart, through lungs, to left side of heart.
Hypertension
High blood pressure
Can lead to heart attack. Caused by lifestyle factors.
Coronary Heart Disease
Fatty layer building up in coronary arteries.
Bits breaking off can form blood clots, blocking the coronary artery.
Caused in part by lifestyle factors.
Respiratory system functions
i) Gas exchange
ii) Immune defence (infection entering lungs)
iii) Talking
iv) Release of chemicals, proteins & enzymes
3 types of respiration
External (breathing)
Internal (exchange of gases in lungs or organs)
Cellular (oxygen being used by cells to create energy)
What does the body use to determine respiration rate?
CO2 levels
Time of useful consciousness at altitude
Moderate & minimal activity
22k feet: 5 mins & 10 mins
25k feet: 2 mins & 3 mins
30k feet: 45 secs & 75 secs
35k feet: 30 secs & 45 secs
40k feet: 12 secs & 15 secs
Altitude at which body reacts to decreasing pressure
7,000ft
Altitude at which atmospheric pressure is half MSL
18,000ft
2 types of hypoxia
Hypoxic hypoxia (insufficient oxygen coming into body)
Anaemic hypoxia (inability of blood to carry oxygen)
Initial symptoms of hypoxia
Euphoria, clumsiness, impaired judgement.
Hyperventilation
- Cause
- Misdiagnosis
- Treatment
Caused by excess carbon dioxide, body attempts to flush it out.
Can be confused with hypoxia which is more serious to treat, more likely explanation at unpressurised high altitude.
Treat by blowing into paper bag, slowing breathing.
Scuba-diving delays
12 hours down to 10m
24 hours beyond 10m
Barotrauma
Gases trapped in your body (e.g. stomach, inner ear, tooth cavity) expanding during descent.
6 main eye components
Cornea - transparent cap, solid shape
Iris - Coloured area in front of lens
Pupil - Gap in middle of iris allowing light through, changes size to control light.
Lens - Transparent, muscles control its shape to focus light
Retina - Back of the eye, covered in light sensitive cells
Optic nerve
2 types of retina cells
Cones: Foveal vision, concentrated in central area of retina, colour sensitive and best in daylight.
Rods: Peripheral vision, further from foveal region, not colour sensitive but work well in the dark and detect movement well.
Autokinesis
Illusion of movement when you stare at a static light in darkness.
How is false horizon illusion caused?
A sloping layer of cloud can be taken as a false horizon leading to adopting a non level attitude
Myopia
- Cause
- Correcting glass type
Short sightedness
Lens is too convex (can’t flatten enough) so light from far away is bent too much and focuses in front of the retina
Concave glass lens to correct
Hyperopia/Hypermetropia
- Cause
- Correcting glass type
Long sightedness
Lens is not convex enough so light from close up can’t be redirected enough to focus on retina (focus point behind retina)
Convex glass lens to correct
Presbyopia
Long sightedness that is common in 40s and beyond.
Presbycusis
Deterioration in hearing due to age
Astigmatism
Curvature of cornea or lens is not perfectly round leading to uneven refraction and distorted images.
Accomodation
The ability to focus on near and far objects
Time required to develop night vision (and adapt to bright light)
30 minutes (and 10 seconds)
Optical illusion caused by rain on windscreen
Makes objects appear lower than they are (so aircraft appear higher) leading to a low approach.
Strongest vision area for rods
10 degrees off centre
Likely effect of approach to brightly lit runway with no other lights near it?
Black hole effect.
Pilot is likely to descend early leading to a low approach
What distance do eyes tend to focus at in the dark with nothing to focus on
1-2 metres
Time before flying after cataract or corneal surgery
24 hours
3 components of outer ear
External ear: Pinna or Auricle, gathers sound signals
Outer canal: Pressure waves pass through
Eardrum: Vibrates in harmony with pressure waves
2 components of middle ear
Ossicles: 3 small bones, forced by eardrum, convert pressure wave energy to mechanical energy.
Eustachian tube: Connects middle ear to nasal passages to allow pressure to match ambient pressure
Barotitis
Air being trapped in the middle ear
2 components of inner ear
Cochlea: Shell shaped part, converts mechanical energy of ossicles to electrical signals
Vestibular Apparatus: Contain fluid and small hairs that detect gravity and acceleration.
Frequency of human hearing and human voices
Hearing: 20Hz to 20,000Hz
Voices: 500Hz to 3,000Hz
Coriolis illusions
- Prevention
Mistaken sense of direction or acceleration caused by vestibular apparatus.
Keep head still and held steady and upright relative to body. Keep turns coordinated with balance ball.
Somatogravic Illusion
Impression of climbing/descending due to acceleration/deceleration
Vertigo
- What is it?
- Potential causes
Feeling of rotation when there is none, or vice versa.
- Disease
- Acceleration
- Sudden pressure changes in ear (blowing nose)
- Flicker vertigo from flashing lights
- Pressure vertigo from blocked eustachian tubes
Motion Sickness
- Causes (3)
- Miss-matching signals between ears and eyes
- Overstimulated inner ear due to turbulence of manoeuvres
- Psychological factors
Blood & bone marrow donation delays
Blood: 24 hours
Bone marrow: 48 hours
Anaesthetic delays
Local - 12 hours
General - 48 hours
Requirement if in hospital
If in hospital for over 12 hours, require CAA or AME input before flying.
Alcohol
- Minimum delay
- Potential time alcohol remains
- Time for 1 unit
At least 8 hours always
Potential remaining after 30 hours
1 unit processed in 1 hour
Amount of alcohol removed from blood per hour
0.01%
Weekly alcohol limit
14 units both men and women
Alcohol limits for pilots
Blood: 20 milligrams per 100ml
Urine: 27 milligrams per 100ml
Requirement for glasses wearers
Must carry spare pair when flying
Requirements to be able to use contact lenses in flight
Been worn constantly and successfully for 8 hours a day for at least a month.
Requires medical certificate endorsement from AME.
Still need spare pair of glasses.
Bifocals
Not allowed.
Need to wear half glasses instead.
Can have bifocals for emergency use.
Do lit objects at night appear closer or further away than reality?
Then appear to be closer than they really are.
Consideration of arousal
Low level of arousal associated with fatigue, sleep deprivation -> poor performance.
High level of arousal is fear, panic -> poor performance.
Optimal arousal is slightly on the low side of the peak performance - to enable response to unexpected events.
Examples of physical or environmental stressors
Heat, cold, vibration, turbulence, noise, discomfort, illness, eye strain, flashing lights, concentration, lack of sleep.
Noise - decibel levels
- Typical cockpit
- Should wear ear protection
- Industry limit
- Causing excess stress
Typical cockpit: 75-80db
Wear ear protection: 80db
Industry limit: 85db continuous
Excess stress: 90db
Melatonin
Produced by the brain to aid sleep.
Is used as a supplement but not approved for pilots.
Don’t fly within 12 hours.
Zeitgeber
Clue or reminder as to the true time of day (e.g. daily events, sunrise, sunset).
Natural day cycle in hours for a person with no clues as to real time
Longer than 24 hours, around 25 hours.
Jet-lag worse travelling east or west and reason
Worse travelling East
This is because days are shortened and the 25 hour body cycle exaggerates the jet lag by another hour.
Travelling west the 25 hour body cycle reduces the initial effect and brings you back into rhythm quickly.
Motor programmes
AKA skills, actions that at one point required full attention but over time can be carried out more automatically.
Receptor
Specialised cell capable of detecting changes in the environment (external or internal).
Adaptation in receptors
The reduction in sensitivity of a receptor as a result of continuous or repetitive exposure to a stimulus.
Sensory memory
The ability to store sensed information before processing, for example noticing after a few seconds that somebody said your name.
Length of time dependent on the sense (only a second for visual, a few seconds for sound).
Agnosia
A brain disorder that interferes with interpretations of sensation and would prevent a pilots license
Different types of memory (4)
- Sensory
- Short term
- Working
- Long term
Short term vs working memory
Short term memory is limited to about 7 items such as a list of 7 numbers, for about 15 seconds.
Working memory lasts longer for items we are focussed on, e.g. rehearsing a list of numbers to hold the memory for longer than 15 seconds.
2 types of long term memory
Semantic: Meaning memory, knowledge in words and understanding such as language or numbers.
Episodic: Event memory
2 types of judgement
Perceptual: Relating to skills that have been learnt (e.g. landing an aeroplane)
Cognitive/thinking: Relating to knowledge based behaviour. Uses brain power and analysis.
Heuristics
A method of judgement relating to rules based behaviour. Using knowledge that “if I do X then Y will happen”
Risky shift
The tendency for groups of people to make more risky decisions that they each would individually
Definition of situational awareness
i) Perception of relevant events
ii) Comprehension of the implications
iii) Projection of their status in the future
Situational Awareness levels
Notice - Understand - Think ahead
Situational Awareness elements
(Categories of things to worry about)
Plane (e.g. instrument settings)
Path (e.g. on track, collision avoidance)
People (e.g. crew, passengers, ATC)
TDODAR process
Analytical approach to decision making
Time
Diagnose
Options
Decide
Assign
Review
TEM
Threat and Error Management
TEM steps
Avoid (Anticipation)
Trap (Recognition)
Mitigate (Recovering)
Threat
An external event of error outside the control of the pilots requiring immediate attention and management if flight safety is to be maintained.
2 types of threat
Environmental (weather, air control, terrain etc.)
Organisational (flight deck, operational pressure)
Error
An action or inaction which results in deviation from pilot intention or expectations and increases likelihood of safety margins being eroded.
3 types of error
Aircraft Handling
Procedural
Communications
UAS
Undesired Aircraft State
Swiss cheese model
Layers of protection against errors viewed as slices of swiss cheese, with errors only occurring when holes in all slices line up
4 layers in swiss cheese model
Organisation
Unsafe supervision
Preconditions for unsafe acts
The unsafe act
Airmanship
The consistent use of good judgement and well-developed knowledge, skills and attitudes to accomplish flight objectives.
CRM
Crew Resource Management
Relationship between SA, TEM and CRM
SA enables better TEM which combined with CRM provides the best possible outcome.
Closed loop system
System in which after taking action, feedback can be observed and corrections made (e.g. pilot flying an aeroplane)
Standardisation of:
- Yoke/sidestick
- Throttle
- Fuel tank controls
Yoke/sidestick - forward to pitch down, left to bank left (etc.) are standard
Throttle - push forward to open throttle is standard
Fuel tank controls - NOT standardised
Parallax error
Misreading an indicator due to seeing it form an angle, based on distance between the needle and image behind it.
Basic T layout
AI is top middle.
ASI, Altimeter, HI are left right and bottom
Turn coordinator & VSI in the bottom corners
Flight director
An indicator which shows you a “target” for the correct attitude to fly the aircraft.
Consists of a triangle for the plane and a dock or crossed lines where it must be lined up.
Is non-verbal or verbal communication biggest component of normal communication?
Non-verbal accounts for 55 to 75% of normal communication (including paralanguage - ‘um’, ‘arr’)
Effect of REM and non-REM sleep
REM sleep recharges the brain
Non-REM sleep recharges the body
Ideal pilot personality type
Extrovert - stable
