Put your money where the risk is

On Thursday, November 28, 2019 at 9:49:10 AM UTC-8, Andy Blackburn wrote:
On Wednesday, November 27, 2019 at 6:07:47 PM UTC-8, 2G wrote:

I did - 20 years worth. Read every last one of the fatals and a lot of the major damage ones as part of an article I wrote for Soaring. I can give you a full statistical rundown as well - by phase of flight, type of glider, region of the country, contest/XC flight vs local, etc.

I think you mis-understood me. A pilot makes hundreds to thousands of in-flight maneuvers every flight hour. Almost all of them executed without incident. Many of them are made based on presumptions about what the airmass, pilot workload, traffic situation, aircraft response and physical/mental capabilities of the pilot are likely to be over the next N seconds. Most of the time the consequences of being a bit wrong on where you are in the probability distribution of all of the above doesn't matter, but sometimes it does. You can attempt to move where you are in the probability distribution of unexpected bad things by increasing your margins, but it's not a panacea.

I would speculate that many of the stall/spin accidents I've seen in the mountains had a fair amount to do with the airmass not doing what the pilot expected. You can say - well, don't fly in the mountains! I think that's not especially helpful. An awful lot of final glides gone bad are the result of persistent sink that exceeded the pilot expectation plus whatever buffer he had. I personally interviewed a number of midair-involved pilots and I can tell you that even with a very good scan your odds of picking up an aircraft on a collision course (particularly if it's head-to-head) is about 50/50. Your fovea just isn't big enough for the closing velocities of aircraft. The Air Force, NASA and various air safety bodies around the world have studied it to death and that's the rough number they come up with. That's one reason we have Flarm - you can't train yourself to have a bigger fovea.

You can call all of that poor airmanship if you want, but I think you're whistling past the graveyard a bit.

Andy

Andy,

I recommend that you do what I did: review ALL of the fatal glider accidents for the last two years and get back to me. Hint: those accidents did not fall into the 0.01% category.

Tom

The air in which we fly is not uniform, sometimes not even honest. Peter Masak, was a great pilot. He met fate flying in an area and conditions he was familiar with. While I did not view his GPS trace I did speak with a pilot whom did. Nothing unusual noted in the GPS. You can stall at any speed and any attitude. We have seen this in the Sierra's. Andy's right on about the stall/spin accidents, sometimes there are other factors. One of the things I worked with a XC student I had was noticing and calling out changes in airmass. Sailors are particularly attuned to this.