Anti-collision mechanism

Don Hammer wrote:
On 1 Jan 2005 15:17:49 -0800, "george" wrotD:

Also, since TCAS has been mandated, there has been only one mid-air
with equipped aircraft and it was because one crew ignored the
warning. (UPS and Aeroflot in Switzerland)

????? You mean the TCAS only gives a warning, with the pilots having a
say on whether or not to take action?? I was under the impression that
the TCAS sytems talk to each other and take automatic action to avoid a
collision!!

To leave it to the pilots doesn't appear to be too much of an
advantage, with a relative speed of two planes being about 1000 mph
towards each other. Also, given the small reaction time, there's also a
chance, howsoever small, that the pilots could both take action that'll
precipitate a collision instead of avoiding one; both diving, for
example.

If it isn't automatic, I think the TCAS should be. For sure.
Ramapriya

EBME, eye ball measuring equipment is the most important instrument you have
in the cockpit. ALL THE OTHER AIDS ARE ONLY AIDS!

Hope this helps,
Peter

"Ramapriya" wrote in message
oups.com...
Don Hammer wrote:
On 1 Jan 2005 15:17:49 -0800, "george" wrotD:

Also, since TCAS has been mandated, there has been only one mid-air
with equipped aircraft and it was because one crew ignored the
warning. (UPS and Aeroflot in Switzerland)

????? You mean the TCAS only gives a warning, with the pilots having a
say on whether or not to take action?? I was under the impression that
the TCAS sytems talk to each other and take automatic action to avoid a
collision!!

To leave it to the pilots doesn't appear to be too much of an
advantage, with a relative speed of two planes being about 1000 mph
towards each other. Also, given the small reaction time, there's also a
chance, howsoever small, that the pilots could both take action that'll
precipitate a collision instead of avoiding one; both diving, for
example.

If it isn't automatic, I think the TCAS should be. For sure.
Ramapriya

TCAS alerts and instructions are what the pilot is supposed to follow. If
ATC and the TCAS conflict then the pilot is required to follow TCAS.

In the case over Germany the Russian obeyed ATC when they should have
followed the TCAS. The DHL plane obeyed TCAS but still ended up wrecked
because the Russian plane had not taken the action it was supposed to
follow.

As with all accidents measures taken earlier could have eliminated the need
for conflict resolution. There was only one controller on duty that night
covering a couple of sectors and he missed the problem as it was building
up. when he tried to raise the Russian plane he had difficulty and so it all
went on.

In the end the controller was murdered by, its claimed, avenging parents of
the 86 kids killed on the Russian plane.

Every regulation brought in is written in someone's blood.

Chris wrote:

TCAS alerts and instructions are what the pilot is supposed to follow. If
ATC and the TCAS conflict then the pilot is required to follow TCAS.

Of interest, here was the Russian view of the priorities at the time:

http://www.aeronautics.ru/news/news002/news053.htm

I believe they have since changed their instructions to encourage the
pilots to follow TCAS recommendations.

In article .com,
"Ramapriya" wrote:

To leave it to the pilots doesn't appear to be too much of an
advantage, with a relative speed of two planes being about 1000 mph
towards each other. Also, given the small reaction time, there's also a
chance, howsoever small, that the pilots could both take action that'll
precipitate a collision instead of avoiding one; both diving, for
example.

1) Reaction times are less of an issue with TCAS because normally
the system will advise the crew of traffic (called a traffic advisory or TA)
when the conflicting aircraft is (iirc) 40 seconds out. This allows the
crew to begin scanning for the potential conflict.

2) If the two aircraft involved in a potential conflict are both TCAS II
equipped, the systems will coordinate. That is, generally the higher
aircraft will get a "Resolution Advisory" or RA to climb (or possibly not
descend) while the lower aircraft will get a descent (or possibly not
climb).


If it isn't automatic, I think the TCAS should be. For sure.

you have far more faith in automation than I.

btw - since TCAS can only see transponder-equipped aircraft, it
wouldn't be real smart to make the system automatic beause you
wouldn't want the system to fly the aircraft into conflict with
a non-transponder aircraft.

--
Bob Noel
looking for a sig the lawyers will like

Bob Noel wrote:

--
Bob Noel
looking for a sig the lawyers will like

ok, how about "A good lawyer knows the law, a great lawyer knows the
judge"

Bob Noel wrote:

1) Reaction times are less of an issue with TCAS because normally
the system will advise the crew of traffic (called a traffic advisory
or TA)
when the conflicting aircraft is (iirc) 40 seconds out. This allows
the
crew to begin scanning for the potential conflict.

You know I'm not an aviator, but 40 secs don't appear that much. A few
secs to initially notice a warning and a few more till it properly
registers would take away much of the 40 secs. Moreover, the pilots
could easily be doing other things at the time - a loo break, chatting
up passengers while on autopilot, munching a snack, even flirting with
a hostess (hope I don't get flamed for suggesting that )...

If it isn't automatic, I think the TCAS should be. For sure.

you have far more faith in automation than I.

and why is it that you don't have faith in automation, Bob? Not having
to use brains, and doing something by rote instead, isn't necessarily a
disadvantage always. The chances of a well-programmed software
consistently doing a collision avoidance routine correctly are better
than two pilots doing so, I'd imagine.

Ramapriya

In article . com,
"Ramapriya" wrote:

If it isn't automatic, I think the TCAS should be. For sure.

you have far more faith in automation than I.

and why is it that you don't have faith in automation, Bob?

because I've seen how avionics software systems are developed

because I've seen the state-of-the-art wrt safety-critical software.

Not having
to use brains, and doing something by rote instead, isn't necessarily a
disadvantage always. The chances of a well-programmed software
consistently doing a collision avoidance routine correctly are better
than two pilots doing so, I'd imagine.

1) the chances of actually having that "well-programmed" software
is pretty

2) I suggest you check out the accuracy of the TCAS II system wrt
azimuth for conflicting traffic. I'm just a software guy, but my hardware
guys tell me that the 4 element (4 pole?) antenna used doesn't give
an azimuth accuracy of even +/- 15 degrees.

--
Bob Noel
looking for a sig the lawyers will like

"Ramapriya" wrote in message
You know I'm not an aviator, but 40 secs don't appear that much. A few
secs to initially notice a warning and a few more till it properly
registers would take away much of the 40 secs.

For a crew that is trained to respond to a TCAS alert by instinct, 40
seconds is plenty.

Moreover, the pilots
could easily be doing other things at the time - a loo break, chatting
up passengers while on autopilot, munching a snack, even flirting with
a hostess (hope I don't get flamed for suggesting that )...

With a professional crew, only one pilot is chatting up the hosties. The
other is flying. A professional crew always has one of the pilots placing
his/her attention on the plane, even with the auto-pilot on.

and why is it that you don't have faith in automation, Bob? Not having
to use brains, and doing something by rote instead, isn't necessarily a
disadvantage always. The chances of a well-programmed software
consistently doing a collision avoidance routine correctly are better
than two pilots doing so, I'd imagine.

Bob understands the limitation of the equipment. It is great stuff. TCAS is
a huge inprovement in safety. However, it isn't infallible. I was on the
jumpseat last week when a fellow crew received a TCAS warning even though a
real threat did not exist. Well-trained pilots who are supplied with good
information will always be the best safety equipment.

For example- the A-320 you have experienced was designed so that idiots can
fly it. The idiots still manage to crash the A-320.

D.

Ramapriya wrote:
Don Hammer wrote:

On 1 Jan 2005 15:17:49 -0800, "george" wrotD:

Also, since TCAS has been mandated, there has been only one mid-air
with equipped aircraft and it was because one crew ignored the
warning. (UPS and Aeroflot in Switzerland)


????? You mean the TCAS only gives a warning, with the pilots having a
say on whether or not to take action?? I was under the impression that
the TCAS sytems talk to each other and take automatic action to avoid a
collision!!

To leave it to the pilots doesn't appear to be too much of an
advantage, with a relative speed of two planes being about 1000 mph
towards each other. Also, given the small reaction time, there's also a
chance, howsoever small, that the pilots could both take action that'll
precipitate a collision instead of avoiding one; both diving, for
example.

If it isn't automatic, I think the TCAS should be. For sure.

20+ years ago I knew one of the early developers of TCAS. She told me
about some of the attempts at conflict resolution. For example, they
started off with a rule that said if two planes were heading directly at
each other, "pass with the other plane on the right". Fortunately,
they did simulations: the result is the colliding planes form a
decreasing-radius spiral about each other, always with the other plane
on the right.