It was 04:00 and I woke up with a dull pain in my left forearm and pins and needles in my left hand. Bugger!
That day I had completed two dives, the first to max depth 44m with an average depth of 38m for 27 mins and completed 31 mins of deco using 50%. The second was to a max of 26m, average 23m for 43m and a min deco ascent with deco clearing at 6m. Surface interval was 3 hours. An uneventful pair of dives from a decompression point of view. The previous day (Tuesday) I had not dived, the day before that (Monday) I only did 50 mins at an average of 21m with 10 mins on 100% O2 at 6m.
For those who are looking for a reason as to my bend, sorry, I don't have one and to be honest, the mechanism and causality for the bend is uninteresting to me in this particular case. Neither of the hyperbaric doctors here in Stromness could explain it either.
Rather, this blog is more about the decision-making processes that happened after I woke up because I believe that most divers...
Many of my readers will have heard about me talk about Professor James Reason's Swiss Cheese Model and how it can be used to show how incident develop because of holes in the barriers and defences which are put in place to maximise safety.
Professor Reason's research showed that at different levels within a system, there are different barriers or defences present. e.g. organisational, supervisor and individual. However, these defences can have holes in them because the organisations, supervisors and operators are all fallible and therefore the defences cannot be perfect.
Ever looked back at an incident or accident to find the reason it happened and realised that you were stressed, tired or distracted and that is what caused the event? These are three of the ‘Dirty Dozen’ which human factors experts have identified as key contributory factors or precursors to incidents and accidents.
The term ‘The Dirty Dozen’ refers to twelve of the most common human error pre-conditions or precursors which lead to accidents and incidents. These twelve have been shown to influence people to make mistakes, errors or violations. The concept was developed by Gordon Dupont in 1993 and is now a key element to Human Factors in Maintenance training.
Note that these twelve are not the only factors which lead to mistakes, errors and violations, but they certainly give you a focal point to identify conditions where errors and violations are more likely to occur. Different domains or even subsets within domains like pilots, ramp crews, air...
It is easy to ascribe ‘human error’ to diving incidents because we often lack details about what happened. It is also perversely satisfying to blame someone, an individual, rather than attribute it to a system issue. Part of this is because we can then start internalising this, distancing ourselves and say that “we wouldn’t have made that mistake”, a natural human reaction.
Unfortunately looking to blame individuals, calling them ‘Darwin Award winners’ or pointing out their stupidity, does nothing to help identify what the real issues were which led to the adverse event, nor do these actions help improve learning because those who have had near misses are scared of the social media backlash when posts are made about events which are so ‘obvious’ in their outcome.
This short piece will cover the Human Error framework from James Reason and look at ways in which we can use this to improve safety and human performance in diving.
The body contains millions of cells, a fraction of which are blood cells. Those cells are broadly split into two types, red blood cells for carrying nutrients and oxygen to the tissues and recovering the waste and CO2 for disposal, and white blood cells which are used to fight ‘bad stuff’ that is in our bodies such as germs and viruses. They both have their purpose but their contribution to the productivity of the human body is somewhat skewed.
By that I mean if we were to look at their productivity over an average year, the red blood cells are really productive, they are used all the time and they support the body’s needs on a second-by-second, minute-by-minute basis. If we stopped the flow of oxygen to the tissues by preventing oxygen being picked up e.g. carbon monoxide poisoning, then the tissues would die relatively quickly. Compare that to the white blood cells, which are primarily used when an infection or anti-body is detected and the body responds by...
One of the worst dives I have undertaken was in the Red Sea on a night dive scootering between the four wrecks on the Abu Nuhas reef. The dive itself had the potential to be awesome. 10 divers on scooters, a mixture of OC and CCR divers (I was on CCR), following the reef from left to right on the image below, stopping off at each wreck for a quick look inside and then moving on. Relatively clear warm water. But it was night time. We entered the water late, around dusk. We hadn't planned it, but there was an issue on the boat which meant we were delayed.
The reason I hated it was because I was responsible for the divers in the group. I wasn't leading it, that was the guide's job, but they weren't keeping track of the divers and I didn't want to lose anyone. At night, 10 HIDs or powerful LEDs all look the same so diver identification was really hard. Ever tried counting 9 black cats in a dark room?! I felt accountable, so I led.
After 70mins, during which...
NTSB Finds ‘Blind Spot’ in SFO Radar After Near-Miss to Aviation’s Greatest Disaster Reports the Mercury News: “The wayward Air Canada plane that nearly caused an aviation disaster at San Francisco International Airport [on July 7th] dropped off radar displays for 12 seconds in the moments before it approached four fully loaded passenger jets on the taxiway, according to new information released Wednesday from federal aviation officials investigating the incident. A source familiar with the investigation called it a “blind spot” that is a half-mile from the start of Runway 28-Right and Taxiway C.” [The link includes cockpit audio]
In aviation, when a near miss of a catastrophic error takes place everyone including pilots, airline companies, government agencies, passenger witnesses, air traffic control and airport administration, all work together on a federal level through the NTSB and the FAA to find the cause.
One of the reasons for...
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