5.2 Fatigue AVMO 0019 study card 22022017

• • Define fatigue.
• • Describe normal human sleep physiology and architecture.
• • List the types and causes of fatigue.
• • Describe the effects of fatigue.
• • Compare and contrast aspects of military and civilian aviation that predispose to fatigue.
• • Outline fatigue countermeasures applicable to the aviation environment.
• • Recommend strategies to prevent and manage fatigue in aviation personnel.

• • Early years
• • Daytime ops
• • Short duration
• • Later
• • Focus on sleep, rest
• • Crew duty hours
• • BUT poor recognition
• • fatigue implicated in accidents

• • 24 hour ops eg 1st Gulf War
• • Circadian rhythm disturbances
• • night ops
• • time zone changes
• Air to Air refuelling
• • ‘Global Power/Strike missions’

-Fatigue

• • A physiological state of reduced mental or physical performance capability resulting from sleep loss or extended wakefulness,
• circadian phase, or workload (mental and/or physical activity) that can impair a crew member’s alertness and ability to safely
• operate an aircraft or perform safety related duties.

• Regular hours of continuous sleep
• Percentage of adult population
• 3-4 8%
• 5-6 15%
• 7-8 62%
• 9-10 13%
• 10 or more 2%

• • Acute / Transient Fatigue
• • Chronic / Cumulative Fatigue

• • Degradation in accuracy and timing
• • Unconscious acceptance of lower standards of performance - poor decision making
• • Unconscious tendency to cut corners & task dump
• • Narrowing of attention - “tunnel vision”
• • Reduced ability to integrate information into overall pattern (“the big picture”)
• • Loss of Situational Awareness
• • Irritability.

• • Decreased physical activity
• • Social withdrawal
• • Visible decrements in performance
• • Increased use of alcohol or stimulants-socially accetable,
• • Appearance of psychosomatic illnesses
• • Irritability/mood instability
• • Increased incidence of chronic disease.

• • Acute fatigue  2-3 days (weekends!)
• • Chronic  prolonged period of recovery (weeks to months to…?).

• • Continuous hours of wakefulness
• • Recent sleep history-quantity and quality
• • Time of day -Circadian

• • Cyclic variations in body functions
• • sleep/wake cycle,
• • body temperature,
• • hormones,
• • performance
• • “Synchronised” mainly by light/dark cycle
• • also social factors e.g. work/rest schedules, meal times.

• Note: Reductions in performance are not result of sleep deprivation
• Body Temperature Psychomotor Performance Reaction Time
• Digit Summation & Short Term Memory

• • Yawning
• • Heavy eyelids
• • Eye rubbing
• • Head drooping
• • Micro-sleeps
• • Loss of appetite
• • Physical exhaustion

• • Slowed reaction time
• • Skip routines
• • Increased carelessness
• • Reduced ability to follow directions
• • Reduced checking
• • Acceptance of increased risk

• • Reduced concentration
• • Reduced attention
• • Reduced vigilance
• • Tunneling of attention
• • Lapses in STM
• • Reduced decisiveness
• • Reduced SA
• • Impaired judgement

• • Reduced communication
• • Withdrawn
• • Reduced energy
• • Reduced motivation
• • Irritability & grumpy
• • Loss of sense of humour

• • Attention deteriorates first, then judgement, then reasoning, Skills deteriorate much later.
• • Fatigued aircrew cannot reliably estimate their own level of performance decrement.

• • Reactionary
• • natural disasters, political will
• • 24/7 standby
• • Operating in inhospitable environments
• • Rest facilities
• • Long duty days.

• • Free-running circadian rhythm gives a “day” of just over 24 hours
• • “West is best” – elongates day
• • Strategy depends on timing
• • Majority of adaptation is in the first 48 hours.

• • After 18 hours awake, performance is equivalent to a blood alcohol level of 0.05%
• • 20 hours without sleep is equivalent to a BAL of 0.08%
• • Performance during out of phase circadian conditions is similar to BAL of 0.1%.

• • Predominately subjective
• • Objective tools available but intrusive
• • Research continuing into other objective measures.

• • Crew duty limits
• • Mission planning
• • Scheduling tools
• • Awareness of fatigue
• • Drugs
• • Hypnotics
• • Stimulants
• • Supervision
• • CO
• • Authorising Officers.

• • Environmental Factors - insist on appropriate quarters
• • Noise, climate, lighting conditions, work patterns
• • Meals at right time of “day”
• • Surroundings differing from home may interfere with good sleep
• • Alcohol (commonly used sleeping aid in the RAAF)
• • suppresses REM sleep
• • leads to more disrupted sleep (rebound wakefulness)
• • result in increased impairment of performance
• • Medication.

• • Follow a routine
• • Make sleep time sacred
• • Don’t exercise prior to bedtime
• • Avoid heavy meals close to bedtime
• • Don’t watch the clock (get up after 30 mins)
• • Avoid caffeine and alcohol.

• • The only true countermeasure, is sleep
• • Professionalism and determination cannot overcome fatigue
• • Practice and repetition allow the task to become “automated”
• • less workload for that task
• • less affected by fatigue.

• • FEGs to issue SIs outlining maximum crew duty periods
• • Consider:
• • aircraft types, operating environments
• • crew workloads and mission profiles
• • disruptions to circadian rhythm
• • normal and augmented crew operations.
• • Maximum crew duty limits may only be varied with Command approval.

• • Pre-mission planning
• • plan sleep periods
• • define critical periods
• • Crew Duty Limits
• • Scheduling tools:
• • Crew Duty and Rest Planner (AVMED/DDAAFS)
• • Fatigue Avoidance Scheduling Tool (FAST) – USAF.

• • Proven to refresh and enhance performance
• • Sleep cycle is 90-112 minutes
• • Take advantage of the circadian lows at 3-5 pm and 3-5 am to nap
• • “Sleep inertia” can last from 15-60 minutes
• • Some people find it more difficult to nap than others
• • Try to find the right sleeping environment.

• • Dangerous distractions cause fight/flight response – adrenaline
• • Adrenaline promotes coning of attention
• • Fatigue promotes coning of attention
• • Extra vigilance when fatigued, especially when distractions occur
• • When things start happening, you have to pay attention to paying attention!

• • Be aware – extra vigilance! (self/others)
• • Adhere strictly to printed checklists
• • read aloud with verbal checks
• • Alternate - activity & relaxation periods
• • e.g. stretching, exercise
• • Posture – minimize discomfort /maximize alertness.

• • Hot foods, fluids, caffeine
• • Start duty time well rested
• • Music/conversation if appropriate
• • Avoid sorties after 0300 (circadian low)
• • Ramp onto night duty
• • Naps - some sleep is better than no sleep.

Always vigilant for any malfunctions, the Captain scans the overhead console while the co-pilot checks the window heating system with his forehead

• • Benzodiazepine hypnotic
• • Dose 10-20mg per 24 hour period
• • Taken not less than 12 hours before start of “aviation-related” duty
• • Side effects rare, dependance possible
• • 48 hour ground trial
• • AVMO prescription only
• • HD 311 refers.

• • “Second line” agent
• • Rapidly absorbed
• • Half life 2 - 3 hours
• • Dose 10 mg ONLY
• • Taken not less than 8 hours before start of “aviation-related” duty
• • Higher side effect risk
• • 48 hour ground trial, AVMO prescription
• • HD 311 refers.

• • “Natural” does not mean “safe”
• • Some with significant medical/psychological effects
• • What is in the filler?
• • Content / purity not adequately regulated for aviation personnel
• • Not approved for aviators without consulting

• • Mild CNS stimulant / reduces effects of fatigue
• • Recognized useful wakefulness aid
• • Performance enhancement due to caffeine effects
• • Also some benefit from getting up to make the cuppa!
• • Max plasma levels in 1 hour
• • Duration 4 to 10 hours in heavy coffee drinkers
• • Side effects
• • Disturbed sleep
• • Tachycardia, raised blood pressure
• • “The shakes”
• • Anxiety.

• • Cup coffee  85mg (60-150mg)
• • Cup tea  50mg (20-100mg)
• • Coca-Cola  46mg
• • Hot cocoa  10mg
• • Red Bull  75mg / 250 ml can.

• • Sleep is a vital physiological need and should be taken seriously
• • People who are fatigued are more likely to make mistakes
• • Sleep requirements should be managed like any other mission asset
• • Often those most mission critical get the least sleep - they feel they are irreplaceable.

• • Three core factors in fatigue are:
• • Continuous hours of wakefulness
• • Cumulative sleep loss
• • Time of day
• • Individuals are poor at assessing the impact of fatigue on their performance
• • Mutual support and command commitment are essential in combating fatigue.

• • Define fatigue.
• • Describe normal human sleep architecture.
• • List the types and causes of fatigue.
• • Describe the effects of fatigue.
• • Compare and contrast aspects of military and civilian aviation that predispose to fatigue.
• • Outline fatigue countermeasures applicable to the aviation environment.
• • Recommend strategies to prevent and manage fatigue in aviation personnel.

• Need a better system for analysing fatigue aspects of incidents and accidents

• • “Chatham House Rules” discussions with members of:
• • Management
• • Workforce
• • Analysis of data from incidents and accidents:
• • May be limited due to format and details collected in the data-base
• • Provide details of overall picture to management, together with recommendations for action
• • WAIT
• • The larger the organisation, the more resistant to change
• • May require “right people” in “right Position”.

• • Commitment is required from two levels:
• • Management
• • Workforce
• • Members must remain engaged throughout the process of review and change
• • Members must feel that they are a part of the process and the development of the solution
• • Without these, even the best R&D will be destined to failure.

• • Never underestimate the intelligence of the workforce that you are dealing with
• • They are smart enough and capable of handling and managing complex tools in their workspace