, • Fault – Good Action, Wrong Intention • Active – Errors with immediate consequence
• Slip – Wrong Action, Good Intention • Latent – Caused by circumstance or
• Currently 1 accident per million movements • Omission – Forgetting to do something surroundings and not directly obvious
• This makes aviation the safest mode of • Commission – Doing something you
transport shouldn’t
• GPWS has been the biggest contributor to • Substitution – Similar to a slip
safety so far
• Pilot error makes up 70% of accidents Threats → Errors → UAS
through lack of good judgement • Threat – External factor beyond flight crew
• Is a subset of national culture influence
• 1 in 1000 times is a good human error rate
• Just - Genuine mistakes are not punished • Error – Internal factors (action/inaction)
• Reporting – Mistakes are reported • Undesired Aircraft State – Unintended
• Informed – Mistake reports are assessed situation causing reduced safety margins
• Has the correct Knowledge, Skills and • Learning – Action is taken on gathered data
Attitudes (KSA) • Flexible – Must be flexible in implementing
• Everyone is responsible for safety as solutions • Environmental – Weather, ATC…
individuals, not just pilots
• Organizational – Operational Pressures,
Manual Error…
• Open Culture – People can share their
knowledge/thoughts
• Closed Culture – No incentive/fear towards • Communication – Missed ATC call…
sharing • Aircraft Handling – Incorrect Config…
• Procedural – Missed SOP/Wrong Callout…
• Ground Navigation – Wrong Taxiway…
• Software – Non-physical aspects like • Aircraft Handling – Unstable Approach,
checklists/SOPs Outside Limits…
• Hardware – All solid objects around the • Incorrect Config – Flight Controls, Mass and
liveware like the aircraft Balance…
• Environment – The varying factors through
• For an accident to happen, multiple active
which the aircraft is operated
and latent failures must line-up such that
• Liveware – The pilot and other people (x2) • Hard – Already in place
layers of safety barriers (the cheese slices)
are ineffective • Soft – Utilizes the KSA of the flight crew
, • Henrys Law – Quantity of gas dissolved into
• 78% Nitrogen, 21% Oxygen and 1% Rare liquid is proportional to the partial pressure 1.Nitrogen absorbed into blood
Gases (0.03% Carbon Dioxide) 2.Pressure reduces
• Proportions constant until 100km 3.Nitrogen bubbles form
• Pain will result from trapped gas – 4.This creates blockages potentially leading to
‘Dysbarism’
tissue death
Key Pressures: • Occurs in the stomach, ears, sinuses and • Caused by Henrys Law
• 760 mmHg at Sea Level teeth
• 380 mmHg at ½ Pressure (18,000ft) • Caused by Boyles Law
• 190 mmHg at ¼ Pressure (34,000ft)
• Joints – “Bends” – Deep pain in large joints
Key Lapse Rates:
▪ This is the primary symptom
• 27ft/hPa up to 18,000ft • Occurs in the stomach
• Skin Capillaries – “Creeps” – Intense itching
• 50ft/hPa above this • Severe pain possible above 25,000ft
• Lungs – “Chokes” – Chest pain
• Relieved by belching, passing flatus
• Brain – “Staggers” – Neurological problems
(farting) and descending
• These symptoms may not be immediate
• 2°C per 1,000ft up to 36,000ft (-56.5°C)
• Isothermal above this
• Occurs in the ear
• Eustachian tube balances pressure • Unlikely below 14,000ft
• MSL-10,000ft – Physiological Zone • Harder to equalise pressure in the descent • Most likely above 18,000ft (unpressurised)
• 10-60,000ft – Physiological Deficient Zone • Relieved by yawning, swallowing, Valsalva • Significant increase in risk above 25,000ft
• 60,000ft+ - Space Equivalent Zone or Frenzel manoeuvre • Scuba diving, obesity and age are risk factors
• Can result in ear drum rupture
• Charles Law – Volume ∝ Temperature • Shallow Dive – 12 Hour Flight Ban
(Constant Pressure) • Can be blocked by infection/cold • >30ft – 24 Hour Flight Ban
• Boyles Law – Pressure ∝ 1/Temperature • Prevents air equalization • Snorkeling presents no problem
(Constant Temperature) • Climbing means the pressure can’t escape • Doing exercise does not prevent DCS
• General Gas Law - PV⁄T = Constant • Descending creates a vacuum
• This cannot be relieved
• Daltons Law – In a mixture, total pressure is
the sum of the partial pressures
• Ficks Law – Rate of diffusion depends on
• Occurs in the teeth
Surface Area, Differential Pressure and
• Trapped gas expands when climbing
Membrane Thickness
• Relieved by descending
• Slip – Wrong Action, Good Intention • Latent – Caused by circumstance or
• Currently 1 accident per million movements • Omission – Forgetting to do something surroundings and not directly obvious
• This makes aviation the safest mode of • Commission – Doing something you
transport shouldn’t
• GPWS has been the biggest contributor to • Substitution – Similar to a slip
safety so far
• Pilot error makes up 70% of accidents Threats → Errors → UAS
through lack of good judgement • Threat – External factor beyond flight crew
• Is a subset of national culture influence
• 1 in 1000 times is a good human error rate
• Just - Genuine mistakes are not punished • Error – Internal factors (action/inaction)
• Reporting – Mistakes are reported • Undesired Aircraft State – Unintended
• Informed – Mistake reports are assessed situation causing reduced safety margins
• Has the correct Knowledge, Skills and • Learning – Action is taken on gathered data
Attitudes (KSA) • Flexible – Must be flexible in implementing
• Everyone is responsible for safety as solutions • Environmental – Weather, ATC…
individuals, not just pilots
• Organizational – Operational Pressures,
Manual Error…
• Open Culture – People can share their
knowledge/thoughts
• Closed Culture – No incentive/fear towards • Communication – Missed ATC call…
sharing • Aircraft Handling – Incorrect Config…
• Procedural – Missed SOP/Wrong Callout…
• Ground Navigation – Wrong Taxiway…
• Software – Non-physical aspects like • Aircraft Handling – Unstable Approach,
checklists/SOPs Outside Limits…
• Hardware – All solid objects around the • Incorrect Config – Flight Controls, Mass and
liveware like the aircraft Balance…
• Environment – The varying factors through
• For an accident to happen, multiple active
which the aircraft is operated
and latent failures must line-up such that
• Liveware – The pilot and other people (x2) • Hard – Already in place
layers of safety barriers (the cheese slices)
are ineffective • Soft – Utilizes the KSA of the flight crew
, • Henrys Law – Quantity of gas dissolved into
• 78% Nitrogen, 21% Oxygen and 1% Rare liquid is proportional to the partial pressure 1.Nitrogen absorbed into blood
Gases (0.03% Carbon Dioxide) 2.Pressure reduces
• Proportions constant until 100km 3.Nitrogen bubbles form
• Pain will result from trapped gas – 4.This creates blockages potentially leading to
‘Dysbarism’
tissue death
Key Pressures: • Occurs in the stomach, ears, sinuses and • Caused by Henrys Law
• 760 mmHg at Sea Level teeth
• 380 mmHg at ½ Pressure (18,000ft) • Caused by Boyles Law
• 190 mmHg at ¼ Pressure (34,000ft)
• Joints – “Bends” – Deep pain in large joints
Key Lapse Rates:
▪ This is the primary symptom
• 27ft/hPa up to 18,000ft • Occurs in the stomach
• Skin Capillaries – “Creeps” – Intense itching
• 50ft/hPa above this • Severe pain possible above 25,000ft
• Lungs – “Chokes” – Chest pain
• Relieved by belching, passing flatus
• Brain – “Staggers” – Neurological problems
(farting) and descending
• These symptoms may not be immediate
• 2°C per 1,000ft up to 36,000ft (-56.5°C)
• Isothermal above this
• Occurs in the ear
• Eustachian tube balances pressure • Unlikely below 14,000ft
• MSL-10,000ft – Physiological Zone • Harder to equalise pressure in the descent • Most likely above 18,000ft (unpressurised)
• 10-60,000ft – Physiological Deficient Zone • Relieved by yawning, swallowing, Valsalva • Significant increase in risk above 25,000ft
• 60,000ft+ - Space Equivalent Zone or Frenzel manoeuvre • Scuba diving, obesity and age are risk factors
• Can result in ear drum rupture
• Charles Law – Volume ∝ Temperature • Shallow Dive – 12 Hour Flight Ban
(Constant Pressure) • Can be blocked by infection/cold • >30ft – 24 Hour Flight Ban
• Boyles Law – Pressure ∝ 1/Temperature • Prevents air equalization • Snorkeling presents no problem
(Constant Temperature) • Climbing means the pressure can’t escape • Doing exercise does not prevent DCS
• General Gas Law - PV⁄T = Constant • Descending creates a vacuum
• This cannot be relieved
• Daltons Law – In a mixture, total pressure is
the sum of the partial pressures
• Ficks Law – Rate of diffusion depends on
• Occurs in the teeth
Surface Area, Differential Pressure and
• Trapped gas expands when climbing
Membrane Thickness
• Relieved by descending
