Decompression sickness, or ‘divers disease’, is caused by nitrogen being released from body tissue during ascent, forming bubbles in the blood stream. The nitrogen released is the nitrogen that was earlier absorbed by the body tissue when spending time under water - a function of time and pressure (plus any remains of previous dives). Divers disease is a serious condition for all scuba divers to keep track of, as it can result in pain, paralysis, or even death. Individual susceptibility can vary from day to day, and different individuals under the same conditions may be affected differently, or not at all. The effects can be modelled with bio-mathematical models, and there are many similarities to the build-up of fatigue in aviation crew Historically, divers disease was avoided by planning the dives carefully, relying on simplified 'dive tables' using anticipated depth and time of the upcoming dive, which may change several times during a dive. When the dive didn’t go as planned, or the individual was more susceptible than the average person - incidents and accidents were not uncommon.
Today, divers disease is more effectively managed through the use of scuba diving computers which continuously keep track of depth and time. They also allow users to set their own additional safety margin. The result has been improvements in scuba diving safety, as well as allowing for longer dives.
Regulatory flight and duty time limits are not that different from the (old) dive tables. They are simplifications, that are neither very practical nor entirely aligned with science or capturing risk with precision. Crew may become fatigued even if they are ‘legal’, while ‘illegal’ roster patterns may be perfectly fine.
Like a scuba diving computer, applying bio-mathematical modelling and using detailed knowledge of the individual and their needed safety margin, CrewAlert has been designed to deliver improved fatigue risk awareness for airline crew. The app contains tailored mitigation strategies, personal 'drop dead limits', etc. and is available for Mac, iPhone, iPad and the Apple Watch.
The CrewAlert app uses actual sleep/wake history collected from wearables, the full crew roster, individual settings, and leading fatigue risk modelling to provide information for fatigue awareness, prevention and mitigation. CrewAlert is free of charge on the Appstore, contains the full Boeing Alertness Model and the ‘pro-features’ are available for a very moderate monthly fee. Welcome to check it out!
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