Safety Notice – Carbon Monoxide Minimisation and Detection in GA
IFA Comment: IFA notes carbon monoxide is a significant hazard. Special attention is always needed to ensure that general aviation aircraft are not vulnerable to this invisible killer.
SAFETY NOTICE Number: SN–2020/003
Carbon Monoxide Minimisation and Detection in General Aviation Aircraft
This Safety Notice contains recommendations regarding operational safety.
Recipients must ensure that this Notice is copied to all members of their staff who need to take appropriate action or who may have an interest in the information (including any ‘in-house’ or contracted maintenance organisations and relevant outside contractors).
Version 3: Issued: 18 July 2023
- 1.1 This Safety Notice is published to raise awareness around minimising the likelihood of carbon monoxide (CO) contamination, highlighting the hazards associated with carbon monoxide exposure and to provide guidance on the use of carbon monoxide detectors in general aviation (GA) aircraft to protect pilots and passengers.
- 1.2 Carbon monoxide poisoning has been cited as a factor in multiple GA accidents globally. In the UK, since 2000 there have been two fatal accidents, one non-fatal accident, and fifteen other incidents where CO may have been a causal factor. The potential dangers of carbon monoxide exposure have been highlighted by the UK Air Accidents Investigations Branch (AAIB) in several recent accident reports – see the Recommended Reading section below.
- 1.3 Carbon monoxide, formed by the incomplete combustion of carbon-containing materials, is a colourless, odourless gas that can cause damage to the brain, heart and nervous system. Symptoms of exposure include headache, fatigue, sleepiness, breathlessness, and degradation in performance. Continued exposure to elevated concentrations can cause unconsciousness and death.
- 1.4 The physiological effects of CO poisoning are cumulative and take a very long time to disperse. Even a low level of CO ingestion, below the level that causes immediate physical symptoms, will cause a progressive reduction in blood oxygen levels which will reduce pilot performance and
potentially cause permanent damage to the brain, heart and nervous system. It is therefore a mistake to assume that a cockpit contaminated with relatively low levels of CO is acceptable as the cumulative negative effects on human performance may not be noticed.
- 1.5 When it comes to CO, prevention is always better than cure. Maintenance is therefore the first, and best, line of defence against CO exposure. However, should maintenance fail, effective alerting of CO presence can be achieved via an appropriate CO detector. This Safety Notice provides guidance on both topics.
- 1.6 In 2022, the CAA concluded a 12-month study of commercially available low-cost active CO detectors and found them to be a net safety benefit to GA. Whilst the risk of CO poisoning may be broadly understood by GA pilots, the same cannot be said for consumers and third parties generally, who may fly in piston engine aircraft on a commercial or recreational basis. Pilots and owners are therefore advised to consider the significant safety benefits offered by active CO detectors, both for their own protection and for their passengers’ as well.