Two die in Glider mid-air

John

So my very next thought was has the encoder/altimeter system been tested
recently?

A standard biannual transponder check for a non-IFR aircraft does not
include a check of the altimeter/altitude encoder system, it just
includes RF tests--a fairly useless throwback to the days of much less
reliable traveling wave tube based transponders. The tests on first
install does include altimeter/encoder tests.

I've seen quite a few owners assume that the encoder/altimeter is being
tested, but unless you've made arrangement with the test provider this
just usually won't be done for these subsequent checks.

A simple test is to compare the altimeter (when set to 29.92"Hg) and
what the TT21 display says for the altitude. But that does not exclude
problems like the static line being disconnected behind the panel or
contaminated with water etc.

If this had happened to me and I'm sure my transponder was working I'd
probably contact the ATC/approach folks and have a chat - this just
should not happen with a TCAS II equipped 737. Unfortunately we don't
have Mode-S RA downlink really used in the USA. When used (like more
widely in Europe) that provides ATC controllers with direct visibility
to RA events in their airspace.

Darryl


On 9/9/11 2:48 PM, jcarlyle wrote:
I'm also puzzled as to why he didn't react to my presence. I would
think that his TCAS would have detected me. Nevertheless, there he was
- no course or alititude variation at all, he just flew right over me,
going _real_ fast. The other thing about it was that he wasn't on a
normal arrival path for PHL. I had my biannual VFR transponder check 3
weeks after this experience, and the Trig TT21 passed just fine. I
don't know what happened, but I hope not to be caught in a similar
situation again.

-John

On Sep 9, 5:14 pm, Darryl wrote:
Something is a little strange here as this seems well within the
altitude difference window that should have generated an RA. Which is a
big deal to the 737 crew both from the immediate required response to
the RA and subsequent reporting/paperwork.

Darryl

Darryl,

Although the encoder/altimeter weren't formally checked during the
biannual transponder check, the technician did me a favor and quickly
checked the correspondance at 0, 5000, 10000 and 20000 feet - they
were OK. I also routinely check the transponder altitude reading
against my alitimeter during each flight. So I'm pretty sure that's
all OK. As for your suggestion about chatting with ATC, that didn't
happen.

-John

On Sep 9, 6:48 pm, Darryl Ramm wrote:
John

So my very next thought was has the encoder/altimeter system been tested
recently?

A standard biannual transponder check for a non-IFR aircraft does not
include a check of the altimeter/altitude encoder system, it just
includes RF tests--a fairly useless throwback to the days of much less
reliable traveling wave tube based transponders. The tests on first
install does include altimeter/encoder tests.

I've seen quite a few owners assume that the encoder/altimeter is being
tested, but unless you've made arrangement with the test provider this
just usually won't be done for these subsequent checks.

A simple test is to compare the altimeter (when set to 29.92"Hg) and
what the TT21 display says for the altitude. But that does not exclude
problems like the static line being disconnected behind the panel or
contaminated with water etc.

If this had happened to me and I'm sure my transponder was working I'd
probably contact the ATC/approach folks and have a chat - this just
should not happen with a TCAS II equipped 737. Unfortunately we don't
have Mode-S RA downlink really used in the USA. When used (like more
widely in Europe) that provides ATC controllers with direct visibility
to RA events in their airspace.

Darryl

Ann Welch, a many time steward at WGC s , always warned against setting G
and R tasks due to the risk of collision; one nearly got me; about 3 secs
warning.
If you are running a cloud street, use the L/R lift indications to turn
slightly; no longer will you be a "stationary" speck to the other pilot and
the wing movment will make you easier to see.
A climbing turn is even better.
John F

Although the encoder/altimeter weren't formally checked during the
biannual transponder check, the technician did me a favor and quickly
checked the correspondance at 0, 5000, 10000 and 20000 feet - they
were OK. I also routinely check the transponder altitude reading
against my alitimeter during each flight. So I'm pretty sure that's
all OK. As for your suggestion about chatting with ATC, that didn't
happen.

-John

On Sep 9, 6:48 pm, Darryl Ramm wrote:
John

So my very next thought was has the encoder/altimeter system been
tested
recently?

A standard biannual transponder check for a non-IFR aircraft does not
include a check of the altimeter/altitude encoder system, it just
includes RF tests--a fairly useless throwback to the days of much less
reliable traveling wave tube based transponders. The tests on first
install does include altimeter/encoder tests.

I've seen quite a few owners assume that the encoder/altimeter is being
tested, but unless you've made arrangement with the test provider this
just usually won't be done for these subsequent checks.

A simple test is to compare the altimeter (when set to 29.92"Hg) and
what the TT21 display says for the altitude. But that does not exclude
problems like the static line being disconnected behind the panel or
contaminated with water etc.

If this had happened to me and I'm sure my transponder was working I'd
probably contact the ATC/approach folks and have a chat - this just
should not happen with a TCAS II equipped 737. Unfortunately we don't
have Mode-S RA downlink really used in the USA. When used (like more
widely in Europe) that provides ATC controllers with direct visibility
to RA events in their airspace.

Darryl

John F,

I understand your cloud street advice, but don't understand "G and R
tasks". Would you please elaborate?

In the case I was describing, I was in a house thermal 3 miles from my
home field, gaining altitude prepatory to starting a TAT. We get
fairly frequent turboprop commuter aircraft running between 4000 to
6000 feet from NW to SE (and vice versa) close to that area (they're
the ones I described as changing course to avoid us gliders), but no
one could recall ever seeing a jet airliner that low going from SW to
NE. It was a strange situation, made worse by him apparently not
detecting me via TCAS or knowing of me via ATC - and of course, me not
seeing him until he was way too close!

-John

On Sep 10, 9:33 am, John Firth wrote:
Ann Welch, a many time steward at WGC s , always warned against setting G
and R tasks due to the risk of collision; one nearly got me; about 3 secs
warning.
If you are running a cloud street, use the L/R lift indications to turn
slightly; no longer will you be a "stationary" speck to the other pilot and
the wing movment will make you easier to see.
A climbing turn is even better.
John F

[quote=jcarlyle;782917]John F,

I understand your cloud street advice, but don't understand "G and R
tasks". Would you please elaborate?


I would think 'Goal and Return' aka Out and Return

Colin