Spotting Traffic

How often do you spot traffic without guidance from ATC when you are out
flying"

How often do you spot traffic called out to you by ATC?

On a recent trip, while flying a PA32-300, I never saw traffic that ATC
called out to me that passed within two miles and 1000 feet vertical
separation. This was a flight of two T-38's.

On my last trip in a C182S with Garmin330 transponder and MX-20 display,
I watch as the display showed traffic passing 1500 feet directly
overhead, but never was able to eyeball the traffic. Earlier in the
flight, I did locate an aircraft 700 feet below and inside a mile.

All of the above occurred during daylight, clear VFR.

T38's are small and hard to see. Clear skies are harder
because there is no background, just bright sky.

Remember, ATC calls traffic in relation to your track, not
heading, so if they say 2 O'clock it can be anywhere to your
right front.



--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"john smith" wrote in message
...
| How often do you spot traffic without guidance from ATC
when you are out
| flying"
|
| How often do you spot traffic called out to you by ATC?
|
| On a recent trip, while flying a PA32-300, I never saw
traffic that ATC
| called out to me that passed within two miles and 1000
feet vertical
| separation. This was a flight of two T-38's.
|
| On my last trip in a C182S with Garmin330 transponder and
MX-20 display,
| I watch as the display showed traffic passing 1500 feet
directly
| overhead, but never was able to eyeball the traffic.
Earlier in the
| flight, I did locate an aircraft 700 feet below and inside
a mile.
|
| All of the above occurred during daylight, clear VFR.

In article ,
john smith wrote:
How often do you spot traffic without guidance from ATC when you are out
flying?

Fairly often, but I don't know how many I missed, obviously.

I've had three near collisions, all away from airports, and two
requiring evasive action. I've had close calls in the pattern when
position reports where horribly wrong, but all of those were resolved
before they got too close for comfort.

The first near collision was at 10,500ft. A bizjet crossed 90degrees
to my path so fast that I didn't have time to react. Range was
less then half a mile. I don't think the bizjet crew even saw me.

The second was at 6,500ft. A Bonanza was off the left side,
90degrees to my path, and wasn't moving in the window. I turned
a few degrees to the left to get off the collision course, and
passed behind the Bo. We got a little bump from the Bonanza's wake
turbulence.

The third was down low, heading eastbound through the pass between
Half Moon Bay and Crystal Springs under the SFO Class B. A Bonanza
was heading westbound on a reciprocal heading at my altitude. With
a closing speed of ~250kts, the Bonanza 'appeared' out of nowhere.
I had to yank hard to avoid the collision.

How often do you spot traffic called out to you by ATC?

For traffic at 5miles, I spot the traffic ~50% of the time. Alot
of times, I get 'traffic no factor' before I can find it. Small
stuff like us is hard to spot, unfortunately.

All of the above occurred during daylight, clear VFR.

Ditto.

See and avoid works pretty well in the pattern, where the close
traffic (1/2mile away) is moving in basically the same direction
as you. Unless someone is flying the opposite pattern or doing
other unfriendly behaviors, the closing rate should be low enough
to see the traffic. And yes, I know most midairs happen at airports,
but I think that is more a factor of the fact that airports attract
lots of airplanes.

Away from an airport, traffic can be moving in any random direction.
Head on, even two spam cans can have a frighteningly high closing
speed. In my head on encounter with the Bonanza, I was a second
away from a fireball.

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

Less than half the time. Even with a callout it is not easy.

Bob Gardner

"john smith" wrote in message
...
How often do you spot traffic without guidance from ATC when you are out
flying"

How often do you spot traffic called out to you by ATC?

On a recent trip, while flying a PA32-300, I never saw traffic that ATC
called out to me that passed within two miles and 1000 feet vertical
separation. This was a flight of two T-38's.

On my last trip in a C182S with Garmin330 transponder and MX-20 display,
I watch as the display showed traffic passing 1500 feet directly
overhead, but never was able to eyeball the traffic. Earlier in the
flight, I did locate an aircraft 700 feet below and inside a mile.

All of the above occurred during daylight, clear VFR.

"john smith" wrote in message ...
How often do you spot traffic without guidance from ATC when you are out
flying"

A few years back, before the New Smyrna Beach Airport (KEVB) had a control
tower
we made all our call outs on the CTAF and while on short final we noticed
something odd.
The image before us was hard to make out but as we got closer to the runway
we realized
that it was a twin on takeoff from runway 20.
The problem with that was the fact that we were on the reciprocal end
landing on runway 02.
The twin was hard to make out because of how low he was to the trees after
he had done
a downwind takeoff without making any calls to anyone (yes we were on the
correct
frequency, we could here everyone else make their calls).
The wind that day was 030 @ 11kts. so that made runway of choice was 02.
That head-on collision was avoided by adding full power and banking hard
right.
But that isn't the end of this story.
We were there to test fly a plane that I was interested in buying.
The owner took us up in the pattern to demonstrate the plane to us but the
first
problem was that he also tried to take off from the wrong runway and was
yelled at by everyone on the frequency.

Since then the New Smyrna Beach Airport (KEVB) now has a working control
tower.

David.

On Mon, 01 May 2006 01:22:53 GMT, john smith wrote in
::

I never saw traffic that ATC called out to me that passed within two
miles and 1000 feet vertical separation.

I agree. It's difficult to spot conflicting air traffic even when
it's only a mile or two away. No doubt, that's the reasoning behind
the FAA's 250 knot speed limit below 10,000'.

As Mr. Macklin indicates:

Remember, ATC calls traffic in relation to your track, not
heading, so if they say 2 O'clock it can be anywhere to your
right front.

There is another insidious inaccuracy in ATC's traffic advisory
information. Termed 'latency' it is caused by the radar antenna's
rotation rate. Targets are updated on the 'scope' once every six
seconds, so the baring provided by ATC is not real-time, but
historical by up to six seconds. (This rate may vary by facility.)

If one assumes a worst case scenario of 250 knot traffic, six seconds
works out to 4,167'/second, or 25,000' (greater than 4 nautical
miles).

Additionally, radar information is remotely relayed to TRACONs, and
then processed by ATC computers. Surely this induces additional
latency, but I have no information on the magnitude of its
significance.

So, with all this in mind, it helps to look along the flight path of
the traffic (corrected for wind) up to 4 NM out ahead of where ATC
reported it.

If you still don't spot the traffic, request a vector from ATC.

And what ever you do, NEVER rely on ATC to keep you separated in VMC;
separation in VMC is ALWAYS airmens' responsibility even if you're on
an IFR flight plan.

As a wise, old airman once opined:

For instance, a pilot who has no fear of a mid-air is an idiot.
A pilot who flies without being constantly aware that he/she is
the main aspect of the mid-air avoidance equation is misguided.
--Dudley Henriques

If one assumes a worst case scenario of 250 knot traffic, six seconds
works out to 4,167'/second, or 25,000' (greater than 4 nautical
miles).

This sounds like orbital speed.

250 knots is 250 (nautical) miles per HOUR, about 250*6000 feet per
hour, or about 250*100 feet per minute. 25000 feet every sixty seconds,
or 2500 feet every six seconds. Half a mile in six seconds. Opposite
direction traffic at the same speed and your relative change is a mile
in six seconds.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

On Mon, 01 May 2006 16:10:37 GMT, Jose
wrote in ::

If one assumes a worst case scenario of 250 knot traffic, six seconds
works out to 4,167'/second, or 25,000' (greater than 4 nautical
miles).

This sounds like orbital speed.

250 knots is 250 (nautical) miles per HOUR, about 250*6000 feet per
hour, or about 250*100 feet per minute. 25000 feet every sixty seconds,
or 2500 feet every six seconds. Half a mile in six seconds. Opposite
direction traffic at the same speed and your relative change is a mile
in six seconds.

Jose

Damn decimal places.... :-)

I appreciate the correction.

In a previous article, Larry Dighera said:
If one assumes a worst case scenario of 250 knot traffic, six seconds
works out to 4,167'/second, or 25,000' (greater than 4 nautical
miles).

This sounds like orbital speed.

250 knots is 250 (nautical) miles per HOUR, about 250*6000 feet per
hour, or about 250*100 feet per minute. 25000 feet every sixty seconds,
or 2500 feet every six seconds. Half a mile in six seconds. Opposite
direction traffic at the same speed and your relative change is a mile
in six seconds.

Jose

Damn decimal places.... :-)

You non-Unix/non-Mac users don't know what you're missing:

[tomblin@chicago ~]$ units
2084 units, 71 prefixes, 32 nonlinear units

You have: 250 knots
You want: feet per 6 seconds
* 2531.7148
/ 0.0003949892
You have: ^D
[tomblin@chicago ~]$

250 knots is 2531.7 feet in 6 seconds.


--
Paul Tomblin http://xcski.com/blogs/pt/
"You must be smarter than this stick ---- to put a machine on the
Internet."

On Mon, 1 May 2006 16:37:27 +0000 (UTC),
(Paul Tomblin) wrote in ::


You non-Unix/non-Mac users don't know what you're missing:

[tomblin@chicago ~]$ units
2084 units, 71 prefixes, 32 nonlinear units

You have: 250 knots
You want: feet per 6 seconds
* 2531.7148
/ 0.0003949892
You have: ^D
[tomblin@chicago ~]$

250 knots is 2531.7 feet in 6 seconds.


I've been a Unix SysAdm since '84, but your response is too arcane for
me. What is that 'bc' or something?