Scared of mid-airs

I sure as hell hope nobody who thinks nineteen seconds is too short
a time to find and recognize a threat and then take appropriate action is driving on my street or flying in my sky (but of course they are).

There's way too many passengers with pilot certificates sitting in the front seats these days. How people scan and how they should scan are often two different things. Flying an aircraft is work, Jose, when done properly. Enjoyable, also? Yes, but it's the "work" part that adds to longevity.

If you are looking at the encroaching aircraft, then nineteen seconds is
probably plenty of time. The point is, usually you are not. You just
scanned that part of the sky. You are now scanning other parts of the
sky. You can't scan it all at the same time. It takes time. You may
not return to that part of the sky for nineteen seconds, except in
general. Conflicts can come from any direction, and you can only see
(well) in a field 10 or 15 degrees wide. It only takes a few seconds
per "block" but there are 24 to 36 blocks, and we are not even counting
what is above or below by more than 15 degrees. So, at two seconds per
look, and 24 looks, we have forty-eight seconds before you get another
shot at the same 10-15 degree area.

Depending on conditions, it may take as much as TEN SECONDS to actually
see the traffic that you are looking right at. The implication of this
is that if you allow two seconds per look, and it takes you ten seconds
to see traffic in the configuration in question, you'll miss it four
times out of five.

But enough theory. How many times have you not seen traffic that was
pointed out to you (2 o'clock and four miles) by ATC? How long did it
take you to find the traffic you =did= see?

http://www.alaska.faa.gov/ata/MACA.htm

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

On Fri, 04 Aug 2006 04:55:32 GMT, Jose
wrote in :

http://www.alaska.faa.gov/ata/MACA.htm

PROPER CLEARING/SCANNING TECHNIQUES

An efficient scan pattern is paramount to visual collision
avoidance procedures. In developing a proper scan technique,
remember that when your head is in motion, vision is blurred and
the brain will not be able to identify conflicting traffic.
Therefore a constant motion scan across the windscreen is
practically useless.

A proper scan technique is to divide your field of vision into
blocks approximately 10 to 15 degrees wide. Examine each block
individually using a system that you find comfortable (e g. from
left to right or starting from the left and moving to the right,
then back to the left again). This method enables you to detect
any movement in a single block. It takes only a few seconds to
focus on a single block and detect conflicting traffic.

A moving target attracts attention and is relatively easy to see.
A stationary target or one that is not moving in your windscreen
is very difficult to detect and is the one that can result in a
MIDAIR COLLISION.

The time to perceive and recognize an aircraft, become aware of a
collision potential and decide on appropriate action, may vary
from as little as 2 seconds to as much as 10 seconds or more
depending on the pilot, type of aircraft and geometry of the
closing situation. Aircraft reaction time must also be added. By
the way, any evasive maneuver contemplated should include
maintaining visual contact with the other aircraft if practical.

There you have it. The FAA telling pilots, that for a 90 degree wide
scan field (45 degrees each side of center), it takes more than two
seconds per 15 degree scan block (at 3 seconds per block, that's 18
seconds per full scan), for a pilot to see a stationary traffic
conflict aircraft growing larger, and it can take up to ten seconds
see-and-avoid (for a total of 28 seconds per full scan).