boulder mid-air

On Feb 7, 3:02*pm, None wrote:

From the description the Cirrus pilot was just not looking ....

Probably wrong:
I have done a geometric analysis of cockpit visibility.
- First, sharp vision -- the fovea -- is only about 1% of the sphere
surrounding us. Our brain integrates peripheral vision and
interpolates detail gathered from the scanning that the eyes do
unconsciously.
- Second, consider all the space eclipsed by stuff:
- the bill of your cap
- the whole of the aircraft beneath you (the Cirrus was descending,
one account says)
- the panel and the sun visor
- the TCAS unit standing on top of the panel
- everything behind you in all directions
- Third, the fact that the aircraft you're about to collide with, even
if it's in your field of view (only about 25% of the sphere) is a
speck on the windscreen that isn't moving -- it's just growing. Our
vision is very sensitive to movement, but insensitive to growth. It's
the movement that directs our gaze, to cause foveal vision to capture
a clear impression of the moving object.
- So: by what miracle of chance do you expect the Cirrus pilot to have
seen through his airplane, to have glimpsed the Pawnee?

*I don't want to be insensitive to the family of the Cirrus pilot, but the
fault was his...In my experience, many IFR pilots
just don't look out for VFR traffic and expect ATC to keep them clear of ALL traffic.

How often have you been the IFR pilot flying with the aid of ATC in
VMC, in a busy airspace? Other traffic is VERY difficult to see even
when one knows altitude and azimuth; much traffic, even collision
traffic, cannot be seen because both aircraft are eclipsed from the
pilot by their own aircraft.
In addition, VFR aircraft often do not check in with ATC to verify
their altitude, or have non-encoding transponders, so that's a
mystery. And then there's the fact that some of us are essentially
invisible to ATC even with a transponder: when we thermal, we're
relatively stationary to radar, which then puts us in "coast" mode,
and removes our blip from the display.
The only way to mitigate this risk effectively is to mandate that
all aircraft, regardless of class, carry operating anticollision
devices.
Unfortunately, the rule-making process is so slow that by the time
any new thing gets through, it's at least decade-old technology and
therefore the target of flames from people who know about the new
technology (ADS-B v. FLARM, for example)
In this regard, at the SSA convention 2 weeks ago, one of the
European attendees said that now that FLARM is established, too many
glider pilots are flying with their eyes in the cockpit and depending
too much on FLARM. Complacency affects every one of us.

Some news articles that contain additional information:

http://www.dailycamera.com/news/ci_14352511
The most complete photos, videos, and summary.

From http://www.thedenverchannel.com/news...00/detail.html
"The Boulder County Coroner has identified the third victim, the pilot
of the Piper Pawnee, as Alexander Howard Gilmer, 25, of Evergreen. His
family asked for their privacy.
On his MySpace page, he described himself as a base jumper, sky diver,
pilot and marine."

"The glider narrowly avoided disaster after pilot Reuben Bakker cut
his craft loose from the ill-fated Piper seconds before the collision,
landing safely 3 miles away and saving his life and those of his
passenger and her 11-year-old son. Their names were not available.

"The glider narrowly avoided disaster after pilot Reuben Bakker cut
his craft loose from the ill-fated Piper seconds before the collision,
landing safely 3 miles away and saving his life and those of his
passenger and her 11-year-old son. Their names were not available.

The glider narrowly avoided disaster after pilot Reuben Bakker cut his
craft loose from the ill-fated Piper seconds before the collision,
landing safely 3 miles away and saving his life and those of his
passenger and her 11-year-old son. Their names were not available.

From http://www.denverpost.com/headlines/ci_14355506
The glider pilot was Reuben Bakker...

From http://www.mercurynews.com/breaking-news/ci_14350203
Sue Patton, 53, and her 8-year-old daughter, Sarah Weller, ran
outside just in time to see two people plunge out of the plane. Patton
said it appeared to her that they jumped.
"The plane was burning really strong," she said. "They really didn't
have a choice.""

This is precisely the problem! The majority of the public, including
many pilots and apparently the FAA, believe in "See and Avoid" since
they can often see other aircrafts either from the ground or when
flying. They do not grasp the simple fact that they only see aircrafts
which are not in a collision course with them! This, combined with
multiple blind spots and the various distractions which are part of
the job of piloting an aircraft, makes it a pure luck when someone
actually manage to see and avoid.
If See and Avoid can be relied on, why do we bother with traffic
lights and multiple lanes on the roads? Yet it is much easier to see
and avoid on the road due to significantly slower speed and knowing
where to look.
It is ironic to hear and read about the money and effort which goes
into investigating the cause of those accidents, while the answer is
simply biological limit of our eyes, and the design of our airplanes.
The only reason that aircrafts do not collide with each other all the
time is the big sky theory. Unfortunately the sky is not big enough,
and we loose many good pilots and passengers to GA midairs every
year.
The responsibility lies with the FAA bureaucrats and the rule making
process, which is so slow that we are still using 50 years old
technologies! Imagine if the FAA was run by, say... Apple.
We would all be carrying a small $99 (ok maybe $999) gizmo in all our
aircrafts, which capable of providing real time warnings for any
threat (such as flarm or ADS-B).
And for those who claims that this will create complacency or heads
down - even if you blind fold all the pilots you will get far less
midairs due to the occasional misuse of malfunction of this
technology, verses relying on See and Avoid!
For a good reading on the subject of see and avoid check
http://www.aviationweek.com/aw/gener...s/bca0107c.xml

Ramy

I think that discussing midair is important in general, so please
continue on.

However, I think it is also important for everyone including your
friends and families to understand that this is basically a collision
between two powerplanes, and one of them just happened to be towing a
glider. This accident has nothing to do with the safety of this
sports. It didn't happen because of the flying characteristics of
glider, the visibility of glider in the air, or having or not having
transponder or similar equipments.

I was wondering why so many initial reports emphasized that the Cirrus
ran into the tow rope. Apparently, there is a perception among non
pilots that the tow rope is miles-long, thus making it an invisible
trap in the air, and the poor Cirrus tripped on it because they
couldn't see it. That is very wrong. The tow rope is only a couple
hundreds of feet long, and you shouldn't get that close to other
aircrafts in the sky anyway.

I even see a headline like this.

Three killed in glider accident
http://www.abc.net.au/news/stories/2...?section=world

-Gen

It will be interesting to see what the NTSB comes up with on this one,
Since unlike most mid-airs this one had a pilot witness and two non-
pilot witnesses in the front row seat (glider) to observe what
happened.

I think that discussing midair is important in general, so please
continue on.

However, I think it is also important for everyone including your
friends and families to understand that this is basically a collision
between two powerplanes, and one of them just happened to be towing a
glider. This accident has nothing to do with the safety of this
sports. It didn't happen because of the flying characteristics of
glider, the visibility of glider in the air, or having or not having
transponder or similar equipments.

I was wondering why so many initial reports emphasized that the Cirrus
ran into the tow rope. Apparently, there is a perception among non
pilots that the tow rope is miles-long, thus making it an invisible
trap in the air, and the poor Cirrus tripped on it because they
couldn't see it. That is very wrong. The tow rope is only a couple
hundreds of feet long, and you shouldn't get that close to other
aircrafts in the sky anyway.

I even see a headline like this.

Three killed in glider accident
http://www.abc.net.au/news/stories/2...?section=world

-Gen

danlj wrote:
And then there's the fact that some of us are essentially
invisible to ATC even with a transponder: when we thermal, we're
relatively stationary to radar, which then puts us in "coast" mode,
and removes our blip from the display.

In the USA, the radar will not remove your transponder blip from the
screen because you are circling; if the blip is from primary mode radar
(no transponder), it may be removed. Radar does know the difference
between clutter and a transponder!

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org