At 20:42 04-06-02 +1000, you wrote: >It's perfectly safe in Australia, Andrew. CASA said so. > >It's only dangerous in England and France. It's so safe in Australia they >can even do it through clouds and in IMC. CASA's collision model says so.
Graeme - Nobody said anything was "perfectly safe" (if there is ever such a level of safety). However, two independent risk management specialists have developed separate models which indicate that the level of risk falls within the range generally considered to be either the "negligible" or the "lower ALARP" range. Read the NPRM on the CASA web site if you don't understand "Level of risk" or "ALARP". These models work by inputting local usage statistics into the formula to decide whether or not a risk is "acceptable" by these criteria, and then applying a variety of risk mitigation strategies to make the risk "as low as reasonably practicable". These include radio broadcast, lookout and cloud height limitations. >I'm not sure whether it was programmed with the average density of >aircraft and parachutists over the continent or the actual density around >busy GA/gliding/parachuting fields (like Caboolture?), but it's >safe. Don't worry. It's completely safe. > >This is only the fourth I know of. Two collisions between gliders and parachutists are referred to in the CASA Summary of Responses - one in France that has already been mentioned in this discussion group, and one in New Zealand that emerged after some digging for information by myself. It seems you know of another - please share the information, offline if you wish. If it affects the data it is vital for your safety that people know. If it doesn't affect the data I STILL WANT TO KNOW (please!). >It's quite safe. > >>...Could it be that they doing something wrong over there? > >Absolutely - they're not using CASA's model. I suspect that if they used the CASA models they might discover that the risk in the situation of a parachute DZ sharing the aerodrome with a gliding operation but without an apparent means of communication would fall outside the acceptable risk area - but until we get the traffic density data we will not know to be able to perform the calculations. Likewise until more information comes to light about the weather conditions (cloud base and amount, visibility, whether the glider was actually based at Hinton-in-the-Hedges or elsewhere and if so, where) we will not know whether the world-first risk management strategy that has been developed in Australia might have averted this unfortunate event, or perhaps might not have done. Incidentally, one of the few en-route midair collisions between a light aeroplane and a glider happened not too far from Hinton, about 15 years ago - and did not raise much of an eyebrow here despite the Nick Goodhart 1955-ish calculation of the "big sky" theory that such an event was only likely to happen once every 357 years or thereabouts. We all take risks of one sort or another every day, often without understanding or knowing the degree of risk that it is. (Who drives a car? a motor-bike? a push-bike? ... How many do so after consuming alcohol, or how many smoke?) Since acceptability is a product of likelihood and severity, you may be interested to know that there is a finite and estimable (not necessarily calculable) chance of half the earth's population being wiped out by cosmic radiation from a nearby star going supernova. (The half of the planet away from the supernova at the time of the radiation reaching earth would be protected by the planet itself!) Current estimates of that event happening place it at one event each 1E+15 years, or 10,000 times the life of the universe. If the number of people killed exceeds 5 billion the overall impact becomes "intolerable" in risk management terms. There are four possible avoidance strategies, involving prior detection and assessment of which star might explode (highly improbable); move to colonise another planetary system remote from the risk star (beyond current technology); sit back and let it happen because we can't affect the occurrence (most realistic and probable); or reduce global population so the severity is reduced into an ALARP or acceptable region of the risk regime (most likely to be successful). Alternatively, we could re-assess what level of risk is intolerable since there is bugger all we could do about it!!! >Graeme Cant Returning to the risk of a parachutist/glider collision, we can all do something for ourselves by avoiding known parachute drop zones (particularly setting locations like Corowa as a turn-point unless we know how to avoid conflict when we get there, or not local soaring from Camden to overfly within 3NM of Wilton [sorry non-NSW people but I had to use a likely scenario]), not operating on a radio frequency that is useless to known potentially-conflicting traffic, and if we do go to such places, being willing to communicate with other probable airspace users. [Robert Hart and others - FYI people expect to find gliders near gliding sites and may - should - use 122.5/7/9 then, but cannot know -and we should not be so self-centred as to expect them to - use these "secret" channels out in general-use airspace. Whilst low traffic density may make the absence of an Area Frequency in 'outback' G airspace a low risk, I am not yet convinced its use would not be a safety and cost-benefit improvement to the National Airspace System. Particularly in North American traffic densities I would consider it to be a useful addition to the system. Rick QA, as a professional risk manager, may care to comment - and please note that although he did not open his posting with it, he was quoting from the Australian Parachute Federation's Safety Officer, who is part of the Canberra aviation community and flies other things as well as plummeting bodies. Anyhow, condolences to those affected by this UK accident, and let's all try to make sure we are not the next ones directly affected. Mike Cleaver My personal, not employment-motivated, views - from my private computer. -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information.
