Strange landing at SJC

Hello again,

On Aug 19, 3:32*pm, Alexander Avtanski wrote:
[...]
I just came back from a walk outside my office in Santa Clara. *Around
3:00pm I saw something quite unusual - while all the planes from San
Jose International were taking off in N-W direction, there was a
single plane (something that looked a bit like MD-80) that seemed to
_land_ coming from N-W, exactly opposite the rest of the traffic.
[...]

I just got an e-mail from a reader of this group (Thanks!), who sent
me links to some ATC audio and pointed out the place where the tower
says that a "flight check Lear will do a low approach to 12R".

http://avtanski.net/images/var/KSJC-...2008-2200Z.mp3

(This is about 20 sec. from the start of the recording).

So, first, shame on me that I could confuse a Learjet with MD-80. It
has been quite low then and it zoomed really fast so it managed to
surprise me and I couldn't get a look, but still...

I checked the approach audio too - at about 24min 20sec of this
recording some guy says something about "we've lost a receiver", but I
can't make the rest. Here's the audio (don't forget to scroll to the
24:20 mark!):

http://avtanski.net/images/var/KSJC-...2008-2130Z.mp3

What's this about? Just curious...

Regards,

- Alex

In article ,
Alexander Avtanski wrote:

I just got an e-mail from a reader of this group (Thanks!), who sent
me links to some ATC audio and pointed out the place where the tower
says that a "flight check Lear will do a low approach to 12R".

Flight Check is the FAA checking navaids. The ILS for 12R was
probably due for a check. I've seen them do a check at Palo Alto
(PAO), and they zipped through the approach really fast, on their
way to the next check.

John
--
John Clear - http://www.clear-prop.org/

"Alexander Avtanski" wrote in message
...

I checked the approach audio too - at about 24min 20sec of this
recording some guy says something about "we've lost a receiver", but I
can't make the rest. Here's the audio (don't forget to scroll to the
24:20 mark!):

http://avtanski.net/images/var/KSJC-...2008-2130Z.mp3

What's this about? Just curious...

FAA flight check uses NAV receivers in the back of the plane coupled to a
computer that checks the ILS equipment. They could have had some type of
glitch in the middle of a run which would require them to do the last run
over. That's my guess.

FAA flight check has numerous planes. They have a few Lear 35s, but most of
their planes are King-Airs. All of them have 2 digit N numbers.

"Mike" wrote in message
news:1S1sk.536$p72.166@trnddc05...
"Alexander Avtanski" wrote in message
...

I checked the approach audio too - at about 24min 20sec of this
recording some guy says something about "we've lost a receiver", but I
can't make the rest. Here's the audio (don't forget to scroll to the
24:20 mark!):

http://avtanski.net/images/var/KSJC-...2008-2130Z.mp3

What's this about? Just curious...

FAA flight check uses NAV receivers in the back of the plane coupled to a
computer that checks the ILS equipment. They could have had some type of
glitch in the middle of a run which would require them to do the last run
over. That's my guess.

FAA flight check has numerous planes. They have a few Lear 35s, but most
of their planes are King-Airs. All of them have 2 digit N numbers.
I used to watch the FAA conduct check flights at TEB and at other times at
SJC. They oftentimes made several runs at the approach NAVAID...on coarse
and at the limit instrument deviation. I don't know exactly what their plan
was but it was more than 1 pass.

"Bob F." wrote in message
. ..


"Mike" wrote in message
news:1S1sk.536$p72.166@trnddc05...
"Alexander Avtanski" wrote in message
...

I checked the approach audio too - at about 24min 20sec of this
recording some guy says something about "we've lost a receiver", but I
can't make the rest. Here's the audio (don't forget to scroll to the
24:20 mark!):

http://avtanski.net/images/var/KSJC-...2008-2130Z.mp3

What's this about? Just curious...

FAA flight check uses NAV receivers in the back of the plane coupled to a
computer that checks the ILS equipment. They could have had some type of
glitch in the middle of a run which would require them to do the last run
over. That's my guess.

FAA flight check has numerous planes. They have a few Lear 35s, but most
of their planes are King-Airs. All of them have 2 digit N numbers.
I used to watch the FAA conduct check flights at TEB and at other times at
SJC. They oftentimes made several runs at the approach NAVAID...on coarse
and at the limit instrument deviation. I don't know exactly what their
plan was but it was more than 1 pass.

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.

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.