The proximate causes have been the usual suspects: WX, terrain, night. No mechanical failures of the type that have plagued, e.g. Qantas for whatever reasons recently.
Statisticians will point out that a "clumping" of events is actually usually a sign of randomness rather than a sign of causality.
The NTSC statement implies that there have been more EMS flights in total (some, they say, unnecessary), and again, if one crash in a hundred flights is normal, then 3x the flights will result in 3x the crashes. Normal statistics.
In short, there may be no "why" in terms of an external factor, just chance, influenced by a larger number of rolls of the dice (flights).
The NTSC suggestions are primarily restrictions that would both reduce flights in iffy conditions and also the overall numbers of flights ("Can this be done with ground transport instead?") which may well be effective in the roll/dice sense, but also likely will affect bottom lines for the services that are private.
The most recent (3 crew/1 child/Aurora IL) was to a hospital at which I used to work, so it cut a bit closer to home than usual. I also live under the approach path to a nearby hospital, so the pictures fall off the walls some nights when the crews are doing approaches (practice or for real).
[edit] @tottigol(below) Hee-hee! I see your point. But I'm not one! My post and the one above it were 'imported' from a different thread, which may make them look a little displaced.
There probably is some "use-it-or-lose-it" pressure as mentioned below, affecting go-no go decisions.
Last edited by pattern_is_full; 30th Oct 2008 at 22:17.