SN-10 user

JJ,

I am so happy things worked out in the end for you. As a low time
pilot I am grateful for the uneventful reminder that things can go
wrong in a big hurry no matter how many hours you have logged.
Although I may raise my personal goals for 2010, my personal risk
margins/limits shall stand a bit longer. Thanks for sharing your
experience. It helps.

Matt Herron Jr.

On Sep 29, 2:59*pm, Darryl Ramm wrote:
On Sep 29, 10:49*am, "
wrote:





Dave - Good luck trying to convince people this was a good decision.
It just appears to be contrary to how others interpret the meaning of
"L" and "A". This is not how I believe all Cambridge products have
used an "L" and "A" attributes, certainly not the C302/303 and I think
older Cambridge devices. With Cambridge effectively defining the
standard for this why was if felt necessary to use the reverse
interpretation that "A" does not imply "L"?

What makes you think Cambridge is defining the standard? *I find the
SN10 format easy and simple to use. *As far as using the A or L to
figure out what kind of airport/landing area the waypoint is - all you
have to do is hit the help button and call up the waypoint description
- then you get all the data about it, including runway length, width,
freqs, etc! *Take a look at the data contained in the CAI format
compared to the NDB format, and you will see the advantage of the
SN10s format.

Kirk
66

Happy SN10 user - who wouldn't use a Cambridge to fill an empty hole
in my panel!

It has nothing to do with whether you like one instrument over
another. Cambridge was here first, and they provided a data format for
their instrument which have widely been used by others. *Dave Ellis et
al. got the whole IGC recorder business started, they proved (in World
level contests) that it was workable, etc. The Cambridge .DAT format
consequently *is* the defacto standard, e.g. it is kind of intrinsic
to Winscore in the USA. Cambridge have an "L" and an "A" waypoint (err
"landpoint") attribute with specific meaning. To change that was not a
good choice, at least use a different letter code to avoid the obvious
confusion. While the soaring turnpoint exchange does a good job hiding
differences, this is just the kind of incompatibility that will bite
sooner or later.

Darryl- Hide quoted text -

- Show quoted text -

First doesn't necessarily mean best, just as the best solution isn't
always the one that ends up becoming the standard - (beta max, anyone
- or PC vs Mac?).

The real solution would be to have an IGC-defined format for
turnpoints that would be universally compatible with all FRs and glide
computers - but barring that, one has to understand their equipment,
and GIGO is always a possibility!

Meanwhile, Leibacher's Soaring Turnpoint Exchange does a wonderful job
of managing all the various turpoint formats.

But let's face it - it really boils down to taking the time to make
sure that your data is correct - an essential part of preflight
planning, just like checking the weather and having a current
sectional in the cockpit!

Cheers!

Kirk
66

(Ok, I admit I do kinda like the 302 vario...)

The 'A' attribute does not cause a point to appear in the
list of landable fields on the alternates page! Only points marked
with an 'L' for landable will be shown.
If true that seems like an really bad design. When you are low you
need a friendly gps with answers, not a bunch of constraints. It
sounds like the SN-10 is not very useful without also having PDA and
moving map.
Chris

On Sep 28, 2:02*pm, JJ Sinclair wrote:
I had a nasty land-out the other day, hit heavy sink while deep in the
mountains east of Williams, Ca. I lost 2500 feet in no time and found
myself below the mountain tops. Went to the 'Alternates' page on my
trusty SN-10 only to find I wasn't within gliding distance of any
listed alternates. I ran east following a canyon that lead to the
totally unlandable terrain east of Red Bluff. Down, down ,down I sank
maintaining about 1000 feet above the slope as I looked at nothing but
trees! Finally I flew over a small pasture that looked to be landable.
It had all my favorite attributes, short, bumpy, fenced, up hill with
trees on the approach end, but at the time, it looked lovely. Popped
the gear and turned down-wind at what looked to be about 800 feet,
pulled full spoiler just before the trees and cleared them by a good
10 feet. Flared with half spoiler and rolled about 10 feet when I hit
a mound that put the nose down hard (Genesis 2). I heard something pop
and then we were flying again. Pulled full spoiler and touched down
again and slid to a stop about 100 feet short of the fence. WOW, glad
that's over!
A few days later I checked my trace and found I was within easy
gliding distance of an airport (Ruth, Ca) when I hit all that sink.
Why didn't the SN-10 direct me to Ruth? Reading the manual, on page 21
it says; The 'A' attribute does not cause a point to appear in the
list of landable fields on the alternates page! Only points marked
with an 'L' for landable will be shown. Ruth was marked with an 'A'
only. Checking the local data bases I find Montague, Air Sailing,
Logan, Avenal, Hobbs and Parowan are all using *'A' without the 'L'
for landable airports.
Recommend everyone check to make sure the data base you are using with
the SN-10 has airports identified with an 'L' for landable attribure.
Cheers,
JJ
PS;The pop I heard on landing was a shear pin that fails when heavy
loads are placed on the nose wheel thereby preventing retraction loads
from being applied to the main gear. An easy fix after I located the
shear pin which is deep inside the nose wheel -well.

Yikes! That sounds like a lot of sink! Glad it turned out.

Goes to show that even multiple thousands of flying hours won't
necessarily show you the worst of what mother nature is capable of
dishing out and even careful prep won't always protect you from
technical snafus that can put you in a pickle.

Best to have a Plan C in case Plan B doesn't work out...in Case Plan A
doesn't work out.

I think Dave meant if an airport is landable it should have both an L
and an A attribute. I assume the turnpoint exchange does the right
thing for each format/computer. The problem is most likely with the
originator of the waypoint file.

9B