We have developed operational limitations for Class 5 medical self-declaration for pilots in consultation with the aviation medicine technical working group (TWG).
Together, we developed a comprehensive risk analysis process. This process aims to manage the increased likelihood of a Class 5 pilot having a medical impairment. The process also helps mitigate the consequences of an accident in the air and on the ground.
The mitigation strategies cover:
- type of aircraft
- type of operations
- number of people exposed
- medical guidelines and excluded medical conditions
- quality assurance processes to validate the risk assessment process.
Availability of data for comparison
The medical self-declaration scheme is a leading initiative. There is no known equivalent non-aviation medical examiner (non-AME) medical self-declaration regulatory model.
This means there is no data in Australia or internationally we can compare to quantify the likelihood of impairment, or the likelihood of an impairment-related accident, where a medical practitioner has not assessed a pilot.
We do have available data on doctor-issued non-AME certificates in aviation and road standards and Class 5 medical guidelines align with these standards. This data indicates the Class 5 pilot population is 5-10 times more likely to experience impairment compared with the Class 2 medical examiner-certified pilots.
Collecting new impairment data
The collection of impairment data for Class 5 medical self-declaration is important in identifying and quantifying the likelihood and the impairment risk for our population. It also helps make sure our assessment is correct.
This risk based on the US FAA BasicMed review: 12% annual risk of death from all causes in BasicMed holders. Australian Fitness to Drive (AFTD) and United Kingdom Driver and Vehicle Licensing Agency (UK DVLA) private driver impairment risk threshold = 20% per annum. Class 2 solo pilot risk threshold = 2% per annum.
Air safety occurrences require mandatory reporting under the Transport Safety Investigations Act 2003.
Under Class 5 medical self-declaration, pilots must report on any medical issue in flight that caused:
- reduced capacity to control the aircraft for any period of time
- them to change flight plan due to the issue. This could be:
- land early
- divert
- change altitude
- hand over control to another pilot.
We will collaborate with ATSB to make sure we reliably capture data for Class 5. The safety occurrence data will inform safety and risk assessment elements of the post implementation review.
Operational limitations explanations
The following material provides rationales for some of the operational limitations.
Maximum Take-off Weight (MTOW)
The certificated maximum take-off weight of no greater than 2,000kg aligns with the UK CAA MTOW requirements for their Pilot Medical Declaration. The MTOW of 2,000kg captures most aircraft on the Australian Register private pilots operate.
This reduces the number of complex aircraft (multi-engine or high-performance) within scope which reduces the cognitive load on a subject pilot.
People on Board (POB)
The limit of 2 people on board aligns with the limitation for:
- Recreational Aviation Australia (RAAus) self-declaration with passenger endorsement
- our Recreational Aviation Medical Practitioner’s Certificate (RAMPC).
This limits the number of people directly affected by the consequence of pilot incapacitation. This is a higher risk under the Class 5 medical self-declaration scheme than under our other medical certification options.
However, please note the number of people indirectly affected by pilot incapacitation could be significantly higher if the incident affects other aircraft or people on the ground.
Altitude 10,000 feet
The altitude ceiling is a risk treatment for aeromedical conditions, for example hypoxia. It is consistent with the limit for RAAus, RAMPC, and Basic Class 2 medical certificate.
Oxygenation of tissues requires the transfer of oxygen from the atmosphere to the body’s cells.
What determines the transfer of gas from the atmosphere all the way through to cells in your body is partial pressure of oxygen. At 10,000 feet, the effectiveness of partial pressure of oxygen drops below the effective gas transfer in healthy adults while 'at rest'. This means while pilots are conducting their duties, they are not considered 'at rest'.
At 10,000 feet, healthy adults start to experience impairment of executive function and increasing demands on their cardiac and respiratory systems. Someone can experience impairment of executive function and increased cardiorespiratory demand at less than 10,000 feet if they experience:
- a health state
- a disease or medication reduces the transfer of oxygen in lungs and tissues
- poor circulation of blood to tissues
- poor carriage of oxygen in haemoglobin or red blood cells
- increased tissue oxygen demand compared with a resting healthy adult.
Pilots with cardiac, respiratory, and neurological diseases will be more impaired by hypoxia from 5,000 feet upwards. They are also significantly impaired at 10,000 feet (below PaO2 50mmHg, SaO2 <90%).
Access to airspace
We foster efficient airspace use and equitable access to airspace for all users when administering Australia’s airspace with safety remaining paramount. The access for Class 5 pilots to controlled and non-controlled airspace follows risk assessment and consultation with our technical experts and the TWG.
A pilot licensed under Part 61 of CASR must demonstrate competencies before operating in controlled airspace. Operating in controlled environments is more structured, formal and demanding. These is also an increased emphasis on safety awareness and willingness to self-report errors or any inability to comply with air traffic control instructions.
Permitting access to controlled airspace (CTA) intends to reduce the likelihood of mid-air collision or collision with terrain. It also reduces the number of fatalities in aircraft and on the ground in the event of these occurrences. This will be done using the existing Airservices Australia systems to maintain separation and manage aircraft movements.
We will review the issue of access to controlled airspace as part of the post-implementation review of the Class 5 scheme.
No aerobatics
Under the Class 5 medical self-declaration pilots are not permitted to conduct aerobatics.
We have based this on a risk assessment of likelihood and consequence of risks of incapacitation in-flight. It also makes sure there is a risk control in place.
Aerobatic manoeuvres subject the pilot to +Gz (“G”) forces which incur significant physiological burden. Aerobatically-capable civil aircraft can expose pilots to up to 9G (modern military aircraft approach 15G).
G tolerance varies based on:
- the rate of onset
- peak G levels
- the use and effectiveness of the anti-G straining manoeuvre
- G-protection equipment
- pressure breathing.
G tolerance also varies based on the pilot’s:
- cardiac function
- respiratory function
- muscle strength and endurance
- hydration
- fatigue
- cerebral perfusion.
Exposure to G can also cause impairment of cardiac and respiratory function, visual function, or balance. Orientation function will reduce G tolerance and increase risk of spatial disorientation.
Fatal accidents are more likely to be the consequence of aerobatic manoeuvres. This is because incapacity is likely to be G-LOC, A-LOC or SD and therefore not likely to be recoverable even from higher altitudes.
No formation flying
The Class 5 medical self-declaration does not permit pilots to conduct formation flying. We have based this on a risk assessment of likelihood and consequence of risks and ensures there is a risk control in place.
Formation flying relies on the pilot’s ability to maintain separation from another aircraft in close proximity. This requires effective function of:
- the visual system around depth perception
- visual acuity and visual fields
- effective integration of the visual system with executive functions to rapidly and accurately respond to aircraft, pilot, and environmental cues.
Pilots require an assessment by a trained clinician using specialised tools and processes for formation flying. This is not part of the Class 5 medical self-declaration scheme.
Any impairment to visual function, including peripheral field functional deficits, field deficits, and depth anomalies will reduce the ability to fly the sortie as briefed. These include impairments to:
- short term memory and learning deficit due to impaired executive function
- maintaining separation, visual field and depth function
- using executive function in time-critical responses to evolving flight situation.
Aircraft in pre-planned close proximity have a significantly lower capacity to tolerate errors from pilots, whether generated from a medical issue or otherwise.
The consequence of mid-air collision during formation flying due to loss of separation is more likely to be unrecoverable. A mid-air collision may also result in both loss of multiple aircraft and severe or fatal injuries to multiple occupants.
Day VFR only (not IFR, IMC or night VFR)
This measure mitigates potential risks of an accident or serious incident because of in-flight visual dysfunction during flight.
The normal operation of the visual system requires pilots to not have a disease or dysfunction of the:
- extra-ocular musclescornea
- pupil
- lens
- retina
- optic nerve
- optic tracts and optic cortex
- executive function integration.
Most of the diseases of the visual system require comprehensive assessment by an appropriate clinician with specialised equipment. This can include disease or dysfunctions such as:
- cataract
- glaucoma
- macular degeneration
- hypertensive and diabetic retinopathy.