On 7/5/2010 8:46 PM, Darryl Ramm wrote:
On Jul 5, 6:38 pm, wrote:
On Jul 5, 8:25 pm, Darryl wrote:



On Jul 5, 5:35 pm, Mike
wrote:

On 7/5/2010 11:09 AM, Darryl Ramm wrote:

On Jun 16, 11:48 am, wrote:
SSA contest report indicates that 2 gliders made contact on the first
day. If the gliders are identified correctly then one continued to
win the day and the other returned to the airport missing part of one
wing and so far has no log posted.

Any more information available?

Andy.

Maybe worth noting that there was also a mid-air collision at the 31st
Worlds on Day 1 (4th July) between two standard class gliders which
was also caught on IGC flight logs. According to the contest web site
both gliders were able to land and the pilots are OK. See flight logs
for 8K and GX (reported as FX on the score sheet).

According to the contest site, one glider had an anti-collision
device, presumably Flarm, the other did not. One glider was thermaling
and the other appears to join the thermal (or at least try to avoid
the thermal circle?) but misjudges and there is a collision. That
pilot had the day disqualified and a two day suspension for what the
CD determined was dangerous flying.

As with the Parowan mid-air there was a gaggle stacked up above the
collision point and the collision involves at least one of the gliders
entering the thermal. Likely a lot of gliders to look at and I wonder
in both cases how much the pilots may have been distracted from seeing
the gliders at the same altitude by looking up at the gaggle above to
help judge the thermal location.

And as discussed in this thread earlier, continuing on task after a
collision is specifically not allowed by FAI rules (Annex A 4.1.4).
Here one glider did continue back to the contest airport/finish. He
was already on the final leg but did seem to pass up several other
closer options to land. I wonder how the CD interprets the 4.1.4 "land
as soon as practicable" requirement, but moot in this case since the
pilot was disqualified anyhow. I mention that only to point it out,
not to judge, without knowing the condition of the glider and
facilities available at the landing sites I do not know what I would
do.

Darryl

I didn't see any mention that there were additional gliders in the
vicinity of the Parowan mid-air. Is there some further documentation
that describes this?

--
Mike Schumann

Download all the IGC files for that Parowan contest day and play those
in SeeYou (EditAdd Flight and do a multiple select on all the IGC
files). There were at least three gliders in a thermal, one just
starting to leave, and the two gliders in the collision appear to be
joining that thermal below those other gliders. I have _no_ idea if
either pilot of the colliding gliders have ever commented on watching
those gliders above or whether this was a factor.

Darryl

i know one pilot who was under the colliding pilots in the same
thermal.

From the flight traces there appear to be two gliders below the
general are of the collision, neither appear to be actually working
the same thermal so I did not mention them. One of them in particular
flies towards and under the gliders a short time after the collide.

It's worth sitting down with SeeYou on a fast computer and playing
either the Parowan or WGC collision in 3D (complete with all the other
gliders) and imagine looking at that other traffic while joining a
thermal. A healthy reminder how easy this is to happen when there are
enough gliders around trying to work the same thermals.

Darryl

This is an interesting insight into this incident. Based on the
previous posts, I had assumed that this collision had occurred between
two gliders in isolation. This certainly provides some explanation on
what led up to this event.

--
Mike Schumann