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obstructive sleep apnoea and aviation safety fact sheet

People with obstructive sleep apnoea (OSA) experience repetitive episodes of partial or complete closure of the upper-airway during sleep. Abnormal relaxation of respiratory muscles causes sufferers to snore, and to sometimes wake up gasping or choking.

While many people with OSA don’t realise their sleep has been disturbed, the condition causes excessive daytime fatigue and poor concentration.

As well as aviation, motor vehicle and industrial accidents, OSA increases the risk of obesity; high blood pressure; stroke; heart attack; type 2 diabetes; depression; impotence, and mood disorders.

When the respiratory muscles relax during sleep in OSA, soft tissues in the back of the throat collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing lasting 10 seconds or more. Sleep clinicians measure the severity of OSA using the Apnoea Hypopnea Index (AHI) and oxygen desaturation levels. The AHI is the number of apnoeas or hypopnoeas recorded during the study per hour of sleep. It is generally expressed as the number of events per hour. Based on the AHI, the severity of OSA is classified as follows:

  • None/minimal: less than five AHI per hour.
  • Mild: more than five but less than 15 AHI per hour.
  • Moderate: between 15 and 30 AHI per hour.
  • Severe: more than 30 AHI per hour.

If you suspect that you have OSA or you have symptoms of OSA, you should see your General practitioner. You may then be referred for a sleep-study so that you can be investigated for OSA and other sleep-disorders, to allow suitable treatment to be implemented if necessary.

Effect of aviation on condition

OSA sufferers may find their condition worsens during aviation due to:

  • irregular work and sleep hours
  • difficulty carrying continuous positive airway pressure (CPAP) equipment when operating away from home
  • lifestyle factors leading to increased BMI.

Effect of condition on aviation

  • overt incapacitation
    • hypersomnolence
    • increased risk of cardiovascular disease, cerebrovascular disease, insulin resistance, hypertension and congestive heart failure.
  • subtle incapacitation
    • reduced attention and concentration
    • degraded cognition.

Implications for Pilots and Controllers

If you are diagnosed with OSA you must ground yourself and obtain a DAME review.

Moderate and severe sleep apnoea is associated with accidents and health problems. Fortunately modern CPAP machines are highly portable. If the CPAP machine you use does not have a data download function, you may need to provide CASA with additional annual specialist reports, sleep studies or other tests.

  • You are not to fly if you experience any problems with your treatment or experience a recurrence of your symptoms.
  • If you are using CPAP, you should use it for at least five hours per night and for six nights per week. It must be used during the sleep period just prior to flight.
  • Effective control reduces the risk of cardiovascular disease, cerebrovascular disease, insulin resistance, hypertension and congestive heart failure.
  • CASA may be able to issue Class 1, 2 and 3 Certification if you can show evidence you condition is being satisfactory controlled.
  • Once you can demonstrate effective OSA management and stability you may only need to show CASA your CPAP download to satisfy review requirements.
  • In case of other treatment modalities, CASA will need you provide other evidence of control of this condition.
  • CASA requires annual review of Class 1 and 3 sufferers of OSA.

Approach to medical certification

More likely to be certified

You are more likely to be certified or recertified if:

  • you can show CASA objective measures which demonstrate your OSA is under control.

Less likely to be certified

You are less likely to be certified or recertified if:

  • you experience symptomatic OSA
  • you show inadequate compliance with treatment regimes
  • you have poor AHI control.

You are unique

Every case of OSA is different. How you are affected by OSA will depend on a range of circumstances. CASA makes aeromedical decisions on a case by case basis. A particular assessment decision is based on the individual circumstances of the applicant under consideration.