Strange landing at SJC

Mike writes:

The number of passes they make depends on what type of ILS it is and what
check they are doing. I've seen them take several hours to do a CAT III
ILS. For a typical CAT I ILS they will check it once per year making about
3 approaches and an arc. Every other year they will do a more extensive
check. The equipment is also checked extensively on the ground at regular
intervals.

How do they fly the plane with sufficient precision to make the check valid?
Or do they use methods that are independent of the precision of the aircraft's
movements (if so, what are they?)?

Mxsmanic wrote:
Mike writes:


The number of passes they make depends on what type of ILS it is and what
check they are doing. I've seen them take several hours to do a CAT III
ILS. For a typical CAT I ILS they will check it once per year making about
3 approaches and an arc. Every other year they will do a more extensive
check. The equipment is also checked extensively on the ground at regular
intervals.


How do they fly the plane with sufficient precision to make the check valid?
Or do they use methods that are independent of the precision of the aircraft's
movements (if so, what are they?)?


They're using differential GPS with a reference
station near the threshold, and usually also an
optical theodolite to track the approcahes.

--

Tauno Voipio (CPL(A), avionics engineer)

"Mxsmanic" wrote in message
...
Mike writes:

The number of passes they make depends on what type of ILS it is and what
check they are doing. I've seen them take several hours to do a CAT III
ILS. For a typical CAT I ILS they will check it once per year making
about
3 approaches and an arc. Every other year they will do a more extensive
check. The equipment is also checked extensively on the ground at
regular
intervals.

How do they fly the plane with sufficient precision to make the check
valid?
Or do they use methods that are independent of the precision of the
aircraft's
movements (if so, what are they?)?


There are a number of different checks that are done. Some are, and this
list is not exhaustive:
1. Installation checks.
2. Routine periodic maintenance checks.
3. Suspected problem (complaints) checks.

The Routine checks are done by simply flying a pre-defined profile and
looking for anything that is out of place. In the other cases, special
equipment is loaded and used in conjunction with regular avionics to monitor
and measure a very large list of parameters. When the data is collected and
analyzed an action plan is created and executed, and then the system is
retested to make sure the problem found is fixed. As you would imagine they
find all kinds of things like bad radios, antennae, new RF energy sources,
RF reflections not there before (new building or billboard put up), etc, and
in some cases, a problem is never found or could not be reproduced. So they
just log it and keep a watch on it.

--
Regards, BobF.

Mxsmanic wrote in
:

Mike writes:

The number of passes they make depends on what type of ILS it is and
what check they are doing. I've seen them take several hours to do a
CAT III ILS. For a typical CAT I ILS they will check it once per
year making about 3 approaches and an arc. Every other year they
will do a more extensive check. The equipment is also checked
extensively on the ground at regular intervals.

How do they fly the plane with sufficient precision to make the check
valid? Or do they use methods that are independent of the precision of
the aircraft's movements (if so, what are they?)?


What's it to you? You don't fly.


Bertie

"Bertie the Bunyip" wrote in message
...
Mxsmanic wrote in
:

Mike writes:

The number of passes they make depends on what type of ILS it is and
what check they are doing. I've seen them take several hours to do a
CAT III ILS. For a typical CAT I ILS they will check it once per
year making about 3 approaches and an arc. Every other year they
will do a more extensive check. The equipment is also checked
extensively on the ground at regular intervals.

How do they fly the plane with sufficient precision to make the check
valid? Or do they use methods that are independent of the precision of
the aircraft's movements (if so, what are they?)?


What's it to you? You don't fly.


Bertie


I remember sitting at a meeting at RTCA, the same people who determine how
your avionics work, and we were having an ergonomics discussion and some
really strange issues were popping up. So I asked the question of the 20 or
so people around the table...how many of you people fly? You know what? I
was the only one. Scary isn't it.

--
Regards, BobF.

"Bob F." wrote in
:

"Bertie the Bunyip" wrote in message
...
Mxsmanic wrote in
:

Mike writes:

The number of passes they make depends on what type of ILS it is
and what check they are doing. I've seen them take several hours
to do a CAT III ILS. For a typical CAT I ILS they will check it
once per year making about 3 approaches and an arc. Every other
year they will do a more extensive check. The equipment is also
checked extensively on the ground at regular intervals.

How do they fly the plane with sufficient precision to make the
check valid? Or do they use methods that are independent of the
precision of the aircraft's movements (if so, what are they?)?


What's it to you? You don't fly.


Bertie


I remember sitting at a meeting at RTCA, the same people who determine
how your avionics work, and we were having an ergonomics discussion
and some really strange issues were popping up. So I asked the
question of the 20 or so people around the table...how many of you
people fly? You know what? I was the only one. Scary isn't it.


That is a bit scary. Not too surprising now I think about it though.

Bob F. writes:

I remember sitting at a meeting at RTCA, the same people who determine how
your avionics work, and we were having an ergonomics discussion and some
really strange issues were popping up. So I asked the question of the 20 or
so people around the table...how many of you people fly? You know what? I
was the only one. Scary isn't it.

Should it be? Ergonomics is a study in itself and largely independent of the
situation to which the study is applied. Pilots are human beings like anyone
else and their human reactions to specific types of external stimuli are
identical to those of anyone else, so general principles of ergonomy can be
applied to a cockpit without necessarily having any experience therein. The
important thing for these people to understand is how human beings and
machines interact, not the specific purpose of the interaction. Or course,
knowing a little bit about the patterns of interaction can't hurt, but they
don't have to be pilots for that (they can just put pilots in a sim and ask
them what they think).

Many people use computers all day, and they suffer fatigue from the poor
ergonomy of their work environment, but their long experience with computers
does not help them to resolve the problems with ergonomy, and they may not
even be aware of them. A specialist, however, might immediately recognize the
problems just by watching a person use the computer, and need not have any
experience using a computer herself.

Similarly, engine mechanics need not be pilots, and pilots need not be
mechanics, at least in theory. Small aircraft require a lot more knowledge of
engines than they really should, though, thanks to the ancient designs of the
powerplants.

"Mxsmanic" wrote in message
...
Bob F. writes:

I remember sitting at a meeting at RTCA, the same people who determine
how
your avionics work, and we were having an ergonomics discussion and some
really strange issues were popping up. So I asked the question of the 20
or
so people around the table...how many of you people fly? You know what?
I
was the only one. Scary isn't it.

Should it be? Ergonomics is a study in itself and largely independent of
the
situation to which the study is applied. Pilots are human beings like
anyone
else and their human reactions to specific types of external stimuli are
identical to those of anyone else, so general principles of ergonomy can
be
applied to a cockpit without necessarily having any experience therein.
The
important thing for these people to understand is how human beings and
machines interact, not the specific purpose of the interaction. Or
course,
knowing a little bit about the patterns of interaction can't hurt, but
they
don't have to be pilots for that (they can just put pilots in a sim and
ask
them what they think).

Many people use computers all day, and they suffer fatigue from the poor
ergonomy of their work environment, but their long experience with
computers
does not help them to resolve the problems with ergonomy, and they may not
even be aware of them. A specialist, however, might immediately recognize
the
problems just by watching a person use the computer, and need not have any
experience using a computer herself.

Similarly, engine mechanics need not be pilots, and pilots need not be
mechanics, at least in theory. Small aircraft require a lot more
knowledge of
engines than they really should, though, thanks to the ancient designs of
the
powerplants.


It was a rhetorical question without a lot of detail. And you answered it
without fully understanding the problem, just like any Senior Executive,
Politician or 12 year old. Absolutely correct, obvious, and useless to
anyone trying to get the job done. ...with no disrespect. And you included
in your answer using far more words than I did, that the underlying problem
was that no one offered experience example.

--
Regards, BobF.

On Aug 27, 8:47 am, "Bob F." wrote:
"Mxsmanic" wrote in message

...



Bob F. writes:

I remember sitting at a meeting at RTCA, the same people who determine
how
your avionics work, and we were having an ergonomics discussion and some
really strange issues were popping up. So I asked the question of the 20
or
so people around the table...how many of you people fly? You know what?
I
was the only one. Scary isn't it.

Should it be? Ergonomics is a study in itself and largely independent of
the
situation to which the study is applied. Pilots are human beings like
anyone
else and their human reactions to specific types of external stimuli are
identical to those of anyone else, so general principles of ergonomy can
be
applied to a cockpit without necessarily having any experience therein.
The
important thing for these people to understand is how human beings and
machines interact, not the specific purpose of the interaction. Or
course,
knowing a little bit about the patterns of interaction can't hurt, but
they
don't have to be pilots for that (they can just put pilots in a sim and
ask
them what they think).

Many people use computers all day, and they suffer fatigue from the poor
ergonomy of their work environment, but their long experience with
computers
does not help them to resolve the problems with ergonomy, and they may not
even be aware of them. A specialist, however, might immediately recognize
the
problems just by watching a person use the computer, and need not have any
experience using a computer herself.

Similarly, engine mechanics need not be pilots, and pilots need not be
mechanics, at least in theory. Small aircraft require a lot more
knowledge of
engines than they really should, though, thanks to the ancient designs of
the
powerplants.

It was a rhetorical question without a lot of detail. And you answered it
without fully understanding the problem, just like any Senior Executive,
Politician or 12 year old. Absolutely correct, obvious, and useless to
anyone trying to get the job done. ...with no disrespect. And you included
in your answer using far more words than I did, that the underlying problem
was that no one offered experience example.

--
Regards, BobF.

My sister in law was of the opinion that she was fully qualified to be
a shoe store manager because, in her words, "has bought a lot of
shoes".

wrote in message
...
On Aug 27, 8:47 am, "Bob F." wrote:

It was a rhetorical question without a lot of detail. And you answered
it
without fully understanding the problem, just like any Senior Executive,
Politician or 12 year old. Absolutely correct, obvious, and useless to
anyone trying to get the job done. ...with no disrespect. And you
included
in your answer using far more words than I did, that the underlying
problem
was that no one offered experience example.

--
Regards, BobF.

My sister in law was of the opinion that she was fully qualified to be
a shoe store manager because, in her words, "has bought a lot of
shoes".


Yes, I ran into a similar situation when I came across someone who said he
was a modem expert. It turned out he worked in purchasing and bought a few
modems. And, we all remember "the Flight of the Phoenix" movie.
--
Regards, BobF.