Scanning is not easy. The eye can detect movement over a 200-degree arc. It can focus on a large aircraft at 7 miles. Outside the fovea focus the aircraft would be visible as a 'still' target at .7 of a mile. An aircraft on a collision course will be a 'still' aircraft with you as the target. A good visual search is most difficult in hazy limited visibility conditions due to 'empty-field myopia'. Your eyes take only 30-40 seconds to return to a default focus of about 10 feet. You will never see the aircraft a .7-mile out. To re-focus your eyes you must sight on the furthest visible object. You must re-focus every thirty seconds to maintain distance capability. It takes about six seconds to see an airplane, recognize as a threat and initiate avoidance action.
Visual scanning is only part of your protective cover. Listening (scanning) to communications will make you aware of possible conflicts before they arise, to surprise. Be where you are supposed to be in the pattern and around airports. Learn where to look to give yourself a greater time margin of safety. Know and avoid instrument approach flyways especially in MVFR conditions. Practice Dutch rolls or slight turns in climb to uncover the nose and make 'still' aircraft 'move'. Divide the windscreen into 15-degree sectors focus on a most distant point in that sector. Watch the ground for shadows. Aircraft shadows are larger than the aircraft. If a fly-speck is moving across your windscreen it will miss you The fly-speck that stays in one spot on the horizon and windscreen is a collision about to happen.
Every turn should be preceded by a focused look on a distant object. Be aware that some places are more prone to have traffic than others are. Avoid the high traffic paths but be watchful for those who may be doing the same. There are some optical illusions that relate to nearby aircraft. An aircraft below you will appear to be above you. While getting closer it will appear to descend through your horizon. All the time it is straight and level below you. Avoid the temptation to dive.
The most hazardous area is near an uncontrolled airport. Few mid-airs occur in a radar environment. However, once traffic has been pointed out and recognized as 'in sight', all ATC responsibility for traffic warning ceases unless you do not report the traffic in sight. (It may be wiser not to report it in sight.) The price of flight freedom is responsibility for avoidance. Mid airs occur most frequently below 3000 feet and in clear skies. 50% occur below 500 feet and 33% in a traffic pattern. The pilot's avoidance scan must not stop when arriving at the pattern. The pattern scan must be both a visual watch and listening watch on the radio. At controlled airports you make a mistake if you put too much trust in ATC's ability to keep you separated from other aircraft. Legally, ATC's responsibility for separation only applies to ground operations. ATC may provide assistance in the air but it doesn't need to. Once you acknowledge seeing an aircraft, avoidance rests entirely with you.
Every radio call by another aircraft is significant. You must learn to discriminate as to how a reported position, intention, instruction relates to your position, intention, and instruction. Some aircraft are not in conflict unless a change is made; others may be in direct conflict. The pilot who does not have sufficient competence to both fly the airplane and monitor the radio is a hazard to himself and everyone else.
How to Traffic Scan
--You must scan the way that is best for you.
--Use a second hand to see how often you really scan for traffic.
--Just looking out without taking the two seconds it takes to focus is non-productive. So is staring at one spot.
--Know where to look. Clear before every turn, especially in the pattern.
--Use S-turns for every climb and descent.
--Look below on final for every landing. The shadow you see may not be yours.
--Make area-clearing turns before beginning maneuvers.
--Make your scan pattern extend to 60-degrees each side of center.
--Scan up and down at least ten degrees from horizontal.
--At one mile, an aircraft below you will give the illusion of being above you.
--Strobes multiply your visibility by a factor of ten
--Be situationally aware of what is said on the radio.
--Talk on the radio giving your altitude.
Scan Patterns
--Variations of the 'block' system work best.
--Use a sequenced series of eye fixations across a 9 to 12 sections of the windows. Two seconds per section.
--At each end at least two blocks are out the sides.
--At the end of each series give the instrument panel a sectional scan.
Near Mid-Air Collision
Definition:
An incident in which two airborne aircraft come within 500 feed of one another OR when a pilot reports he has come 'too close' to another aircraft. Only aviation collects this mode of statistics.
Classification:
Critical--where avoidance occurred only through chance.
--within 100 feet"
Potential
--where avoidance occurred because of pilot action
--within 500 feet
No hazard--where direction and/or altitude made collision unlikely
--14 percent of NMACs result in FAA enforcement
--5 percent of NMACs result in ATC controllers
--Increase in NMACs is due to improved reporting
--Majority of reported incidents involve at least one uncontrolled VFR aircraft
--The annual average of actual airborne collisions is less than 30
--Probability of an actual airborne collision is one in two-million
--One VFR vs one IFR is most common (60%) incident
--VFR vs VFR is next at 33%
--IFR vs IFR has 7%
--Altitude reporting was not required until 1987
--16 per year = 1 per 1.6 million flight hours since 1995.
--56% have fatality
--60% of all aircraft landed safely
--All mid-airs since 1983 occurred in VFR conditions.
--Bright sunlight considered a common factor.
--88 of colliding aircraft show no signs of evasive action.
--12% did take evasive action but too late.
--Most mid-airs have slow closing speeds.
--Formation flights were 14% of mid-airs.
--Experience is not assurance of not having a midair.
--A small aircraft is recognizable at a maximum of 1.5 miles.
--This means that all the point-outs by ATC beyond that distance are useless unless they are coming closer.
--At 1.5 miles the average closing speed of 200mph takes 25 seconds.
--Recommendation, don't bother looking, advise ATC that you will accept a vector.
--See and Avoid has limitations as a way to reduce the midair accident rate.
--The mid-air and G.A. accident rate has improved throughout the years I have been flying. See, I made a difference.
--TCAS in airline sized aircraft have had dramatic reduction of midair effects since 1978.
--Eliminated mid-airs among airliners.
Runway Incursion is the 'Drug War' of Aviation
--Has been equated to a dog that chases parked cars.
--Human error by people are the problem
--Only if technology improves in other areas then runway incursion will be a major cause of fatalities.
--Training to increase awareness and understanding.
--Technology to use automation to reduce the human input into the equation.
--Procedures that take the initiative to reduce risks and potential for error
--Signs/markings/lighting to reduce potential for error.
--Data accumulation to improve ability to learn from past experience.
--Local Solutions designed to improve the airfield and infrastructure.
--Eliminate unnecessary, unneeded, redundant, repetitive, echoic, reiterative verbiage.
--Optimize human memory capacity
--Enhance distribution, clarity, interaction, and notification.
--Improve remediation of people involved.
Ground Marker System
Concord (Buchannan Field) CA is the first airport selected for installation and evaluation of system.
Designed to use existing aircraft marker beacon frequency and marker beacon common to majority of General Aviation aircraft. Airports will use underground sensors (similar to highway sensors) to send voice messages into cockpits of aircraft approaching sensor position. An ATC laptop computer has a digital voice library to advise aircraft of any one of six locations on the airport. Cooperating aircraft are asked to have their Marker volume up and to fill out a questionnaire regarding use and effectiveness as part of the program. Online at http://
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