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Avoiding Other Aircraft
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Instructional Collision Avoidance; The Art of Avoidance; Planning Avoidance; Controlling the Hazards; ...Situational Awareness; ...It's Called Imagination; ...Cockpit Management; ...Accident Prevention;...Traffic Alert and Collision Avoidance Systems; ...Proximity Warning Indicator; ...Collision Avoidance Learned; ...Avoidance Checklist; ...The Way to Use Your Eyes; ...How to Traffic Scan; Near Mid-Air Collision; Runway Incursion is the 'Drug War' of Aviation; ...Ground Marker System Mid-airs Revisited; ... Midair Collisions; Avoiding the Midair; Learning to Recognize Conflicting Traffic; Being Situationally Aware; ...Mid-air collisions 1977-1986; ...My Web Posting; ...Helping Aircraft See You; ...Avoiding Arriving Aircraft; ... Mark I Eyeball; ...Reasons You Can't See; ...
Instructional Collision Avoidance
When I started instructing ground school in 1968 instructional flight instruction was a low percentage of all general aviation midair accidents. Ten years later instructional accidents equaled the same number of mid-airs as occurred during personal flying.
The cause/solution of this was multiple:
--The student is preoccupied with doing what he is doing.
--Students undergoing instruction do little scanning.
--Student relies on instructor to avoid aircraft.
--The instructor must get the student to scanning by teaching scanning skills.
--Aircraft scanning must be three-dimensional not the automotive two-dimensional.
--Students mimic the instructor
--Radar contact does not change PIC responsibility to see and avoid.
--The volume of traffic often overwhelms ATC traffic avoidance procedures.
--Radio communications is the best single universal aid for the individual pilot.
--Eyes outside the cockpit is still the most reliable means of aircraft avoidance.
Art of Avoidance
--The limitations of your eyes are a major weakness of the 'see and avoid' concept.
--80% of our total acquired information is via our eyesight.
--The understanding of how our vision works and does not work makes our seeing better.
--Your eyes are vulnerable to dust, fatigue, emotion, germs, age, alcohol and optical illusions.
--In flight vision factors are atmospheric conditions, windshield distortion, oxygen, glare, lighting, design and most of all vagaries of the mind.
--We see only what our mind lets us see.
--Our eyes require time to accommodate to different focal distances.
--If not focused the eyes default to no focus.
--It takes one of two seconds to accommodate to distant focus
--Once you see something you need ten more seconds to do something about it.
--Our field of focused vision is very narrow. We visualize an arc of 200 degrees but see less than 15 degrees.
--Motion can be perceived in the periphery of our visual field. A plane on a collision course will not move.
--Covering the sun with your thumb was a WWI way of looking into the sun.
--A plane just before it hits you will 'blossom' to fill the windshield.
--Flying into the sun you can't see but 'they' can.
--Flying away from the sun you can see but 'they' can't.
--The degree of contrast between a plane and the background determines if it can be seen.
--Your mind can cause cockpit myopia where it fails to 'see' what your eyes are looking at.
--Pilots tend to over-estimate their visual abilities along with everything else.
Once on a flight the most likely cause of an emergency is going to be related to pre-flight preparation. This may relate to aircraft capability, maintenance, fuel, weather, or routes. Either singly or in combination, these planning factors can combine to create an emergency. Flight planning can control and reduce accident probability by such things as flying airport vicinity routes, altitudes, climbing at Vy, etc. The pilot's reasoning process at emergency occurrence makes a big difference, saving the airplane rates low on the important scale, survival rates high. Have a checklist that keeps the priorities in order. Change your mind only once. Make the most conservative response to preserve or improve the current level of safety. No flight is so important that it must be made.
The use of intelligence and knowledge can minimize the effects of attitude and personality in assessing flight risk. This means the ability to integrate knowledge, vigilance, selective attention, risk identification, information processing and problem solving into the processing ability of your brain. An alternate airport is part of the plan as are engine failure and weather changes. This planning is part of your training program. Contingency planning applies to a particular flight. You set up with those in the plane and those concerned on the ground an alternative contact or plan to cope with possibilities. Tell someone at home of your planned route, destination and alternatives. Arrange a communications program to cover these situations and the unexpected.
All activities involve some degree of risk. Flying, due to its multi-dimensional complexity, has more than its share. Risk can be managed if the pilot has properly prepared for the flight and is proficient and current in the required skills. Preparation is mental, physical and mechanical. Proficiency requires recent flying in aircraft type and weather conditions. 72% of pilot accidents have occurred where pilots are not trained or current in the conditions surrounding the accident. If you think training is expensive and stressful, just wait until you have an accident or a visit from the FAA.
I recommend that we avoid flying at 3000' or 2500 VFR at all times. 2850' is just as legal and safer. Practice airwork over hilly terrain where 4250' is again both legal and safer. Stay within gliding range of the flatlands. Avoid flying direct to VORs. If you really wish to avoid aircraft, fly early in the morning. This practice works fine unless you plan to cross MOAs in Nevada. Military pilots know the advantages of morning flights, too.
"Operation Lights On" was an FAA suggestion that landing lights be used to improve detection between aircraft. Some aircraft systems now have landing lights that pulse to attract attention. During the bird migratory season the lights enable the birds to see and avoid. During periods of low visibility the ATIS may request that landing lights be used for airport arrivals and departures. If you are showing a light so advise ATC when you make your call-up. The use of strobe in daytime flying increases you visibility by a factor of ten.
Many of the Bay Area airports now have BRITE radar displays that allow radar location but not identification of nearby aircraft who can accurately give their arrival location by radio. This will greatly improve the specialists' ability to make a visual sighting. They are starting to call aircraft 'in sight' long before they turn downwind and may clear them as #1 to land.
Practice VOR tracking and holding patterns at 850' AGL. Use a suitable VOR. You are much less likely to meet another airplane that low. The VOR is more sensitive and requires more precise flying down low. Do your airwork about 600' below the floor of a Class B shelf that is not used as a flyway. Most pilots are insecure in their ability and knowledge of Class B operations to do flight operations there. This makes for fewer airplanes in the area. Get and use radar advisories where available.
Always make 45-degree entries to uncontrolled airports. This particular FAA recommendation has been the largest single reason for reductions in mid-airs over the past twenty years. A common fault of the 45 entry is the failure of instructors to teach that the 45-entry is aimed at the landing threshold and not the mid point of the runway. By doing this the inbound aircraft will double the separation of departing traffic making standard 45-degree departures. Draw it out and you will see the difference..
arrive at airports via routes and altitudes that you know are
often used by other aircraft. There are many occasions when closer
to the ground can be safer. You know that departing traffic coming toward you
is climbing or at least should be. This means you will be safer down
low, sooner than later. Monitor local frequencies when following
freeways down low. The CHP flies low and slow even in marginal
conditions. When flying along roads or valleys stay on the right
Cross-country flights should be at altitudes high enough to minimize any local traffic conflicts. Don't follow airways and keep a good lookout when crossing airways regardless of hemispheric rule. Airways are eight miles wide and not all cross country pilots update altimeter settings. Pilots who are insecure in their pilotage skills tend to follow airways.
Know where the local flight schools have their practice areas. Sierra out of Oakland likes to practice Southeast of Mt. Diablo. There is a small legal aerobatics area East of Mt. Diablo. There is a very busy flyway North to Northeast of Concord. It is best to avoid this quadrant at altitudes less than 5000'. Another busy route extends from San Jose up to CCR along 680. The preferred altitude for this route seems to be 2500 so choose some other altitude..
Over 50% of all accidents occur because of pilot perceived time pressures. When an individual feels time is important the brain begins to screen the available information so as to get a desired flight plan result rather than the safest one. The pilot becomes so focused due to time pressure that other available options are outside the perceptive scan.
A difficult flight decision can be avoided by making an early decision for avoidance. When two choices appear regarding fuel, get fuel; when two choices appear regarding weather, turn back and avoid; when two choices regarding fatigue appear, stop and spend the night. As part of pre-flight planning poise several two-choice options as might occur and make your decision ahead of time. These pre-decided selections should exist for both situations requiring instantaneous choices such as engine failure on takeoff as well as choices of where to eat en route.
I have always emphasized situational awareness without using the term. Prior to every training flight I review the flight plan and the reasons for certain procedures, altitudes, and performance parameters. You must know where you are in the operational environment and where others say they are. This reduces your risk but does not eliminate it.
The pilot who is actively participating in securing his situational awareness is spotting potential trouble before it occurs. The people in the front seats should be involved totally with flying. We must separate the flying from being a tour guide. Flying is made up of practice and discipline, and requires practice a discipline to keep flying the airplane as #1. A side conversation will make you less aware of the flight situation. Complacency, lack of attentiveness, and distraction is a prelude to an accident.
If you are pleased with your flying, situation, and competency, you are most likely complacent. Fly as though you were in trouble, worried, watched, and tested on every flight. Look for things that are close to right without being right. Don't accept 'close' if perfection will increase your alertness. Use of the checklist to perform critical tasks reduces the natural tendency to become inattentive. A little discomfort can be considered a positive influence, especially when flying alone. Hand-flying will keep you awake.
The more aware you are, the better your cockpit management, the better will be your defensive flying performance. More importantly, when your performance is up to standard you can detect the elements of the pre-accident sequence. The accident sequence begins on the ground, in most cases. The presence of risk may not be as apparent but it is on the ground where risk reduction begins. There are a number of personal stress factors, which dominate here.
The risk of an accident or an emergency begins very slowly and progresses cumulatively to ever increasing levels in a very orderly sequence. The pilot's ability to recognize and interrupt the sequence determines his ability to make an early on plan change to break the risk sequence. Stress interferes with the reasoning process. As the sequence develops the pilot get in over his head without realizing it. He has failed to allow any options as they occurred in the sequence. The unanswered multitude of questions surrounding every flight decision you make determines your proclivity for emergencies. In most accidents there is a sequence of events where the pilot should realize that continuance would push the capability envelope. This sequence most often begins with getting into the airplane.
Situational awareness means that the pilot is knowledgeable of the risks inherent in a given flight condition? Why is it more desirable to initially climb at best rate rather than cruise? When should a pilot opt to fly close to rising terrain? To what extent should a pilot trust a tower or radar controller? What options does the pilot have? What changes in flight procedures are desirable under SVFR or at night? The pilots knowledge and awareness of the real risks sets the threshold of tension onset and thereby the decision making process. Even smart people make dumb mistakes. Anyone can get lost; it takes an expert to stay found.
The accurate perception and understanding of all the factors and conditions within the four fundamental risk elements (recognition, evaluation, selection,
performance) that affect safety before, during, and after the flight.
Knowing where you are, why you are there, how you got there and how to get away.
It’s Called Imagination
---Yes, but it’s really situational awareness.
---Situational awareness is more than just knowing where you are.
--- Situational awareness means knowing where everything and everyone else is.
--- Situational awareness means knowing where everything fixed and moving will be relative to you.
---ATC is playing this ‘game’ with all aircraft on the frequency and you must play it as well.
---This three-dimensional chess requires imagination, anticipation, attention and caution.
---Caution is displayed by your letting ATC know when your situational awareness screen goes blank.
---You can do this in two ways over the radio:
---Ask ATC to point out unknown traffic by position and altitude
---Talk ‘beyond’ ATC by giving position and altitude in hopes the unknown traffic get the message.
---You can practice situational awareness by reflecting on what has happened in a past situation.
---Reflection involves thinking how something may have been done differently or better.
---Practice reflection by visualizing an airport or pattern situation that happened and how to make it safer.
---Some visualize better than others do but imagination will give flashes of insight of what to do next time.
For the past twenty years there has been slow but steady improvement in the safety of flying. Some of these improvements have been in technology but the greatest change has been in reducing pilot caused accidents. The pilot must establish for himself personal minimums. He must live by them even though they may be well above FAR, published, or POH figures. Higher personal minimums will give more options and reduce anxiety of your flying. Never second-guess your personal minimums.
Advise a second pilot or passenger of all the above information on a 'nice to know' basis rather than on a 'need to know' basis. The better informed others are the better they can monitor your behavior and performance. Your companions are a resource of information to be used. An informed resource is the most useful.
You are not likely to have a minor accident with an airplane. Any repair is apt to be very expensive. The FAR's make the pilot the ultimate responsible party. ATC instructions are 'clearances' which leave the pilot responsible. Every flight is composed of numerous choices and decisions. Flight safety is based on the pilot's discrimination in selecting these choices and decisions. The pilot who is in the most need for accident prevention training is often the least likely to seek it. The once a week pilot often falls victim to accidents in which proficiency has been allowed to deteriorate to dangerous levels. 47% of the 80s-decade accidents were the result of incorrect judgments and decisions. Safety must be the paramount choice in making hard decisions. When in doubt make the safe choice.
If what you do in an emergency as a pre-planned procedure you have made the big step to avoiding the panic that kills people. Knowing what to do should not promote a feeling of invulnerability. We must have respect for the 'possibles" that occur in flying. We plan every flight for the best safety. When something goes wrong we must know decisively where to start and how to proceed. Indecision is often worse than doing nothing. As with everything in life, we can make a difference. Aviation safety investigations have shown that accidents are due to a lack of basic knowledge and flying skills, a complacency that whatever happens won't happen to you, and entering into a flight environment that contains flight hazards. Alone or in combination these await all of us given sufficient time. Again, remember your life's ambition is to be an old pilot.
All to frequently accidents are the result of a pilot's failure to know what he is responsible for knowing about his aircraft, its performance and systems. Just having a great deal of time is type is no assurance of adequate knowledge. POH knowledge should be reinforced by periodic refresher study. The first item on any FAA investigation is as to whether the pilot knows all he should know per FAR 91.103. You should be able to pass a blindfold cockpit instrument, controls and systems check. You should know the specifics for both normal and emergency operations.
Memory is the primary accident culprit. We forget or ignore those skills and cautions we had as students. We develop a false sense of competence. Memory is the source of common sense and good judgment. You remember what you have learned and have been taught about the flying factors that will keep you alive and free from accidents. Additionally, you must be constantly immersed in the literature of aviation in order to remain aware of the many changes that are part of the continuum of being a competent pilot.
Traffic Alert and Collision Avoidance
TCAS uses transponder equipped aircraft to display a plan view of aircraft position and collision threat. It does this by predicting flight path. Latest types tell pilot which way to go for avoidance. There have been a few false warnings.
Proximity Warning Indicator
Uses strobe light indications to display indicator lights as to give azimuth out to a range of one mile. These lights are found on TV towers.
Because you are inside a cockpit there are a number of inherent factors that will make it harder for you to see another airplane. Pilot fatigue, anoxia, a dirty windshield, cabin design, time of day, age, stress, temperature, illusions, window distortion, or distraction can make it more difficult for you, the pilot, to see another aircraft.
77% of mid airs occur between overtaking aircraft from tail or side. You will most likely never see the aircraft you hit or that hits you. Collisions are frequently caused by failure to follow ATC avoidance instructions. The charts tend to emphasize the element of high speed closure rates as being the hazard. This is not so, since only 5% of the mid airs are even partially nose to nose. The closure rate between a vast majority of midair accident aircraft is a speed less that the cruise speed of either aircraft. As you might expect the faster aircraft overtakes the slower. Knowing the facts can protect you. 50% of all mid-airs occur at less than 500' AGL. Another short 25% happen above 3000'. 92% happen in good VFR.
If you should have a view of the aircraft that you are going to hit, it will creep slowly into view and will not appear to move on the windshield. It is this lack of movement that makes the aircraft so hard to see. There is a lag time of over six seconds between looking, seeing and recognition of another aircraft as a problem. An additional six seconds is required to put an reaction into effect. At a 90-knot closure rate from a half-mile you will have less that eight seconds to avoid the collision. Not enough time. You must see the plane further away if you want a survival chance. You are unlikely to see a plane beyond a mile that is not moving on your windshield. In the final moments the other aircraft will blossom to fill the entire window. You are out of time.
The narrowness of our focused field of vision, only 10%, is a primary limiting factor in our ability to see an airplane. If you have not had an opportunity to focus your eyes to distance in the past 30 seconds your focal distance may be less than 50'. A window post that blocks from seeing with one eyes inhibits your vision.
You do have some options. You can deliberately avoid common altitudes. You can vary your aircraft course, attitude, and altitude. You can make a deliberate effort to move the head forward and back. You can know where to expect and look for other planes. You can do much of the work of the cockpit like copying the ATIS, looking at the charts by doing the copying and looking up near the windshield so that you can split your visual field. Under no conditions should you look down into your lap in a known traffic avoidance situation.. Even three seconds of instrument scan should be a maximum. Use your lights.
Additionally, avoid those areas, routes, and altitudes that are known to be frequented by other aircraft. Know that you have the total responsibility to see and avoid other aircraft. If you acknowledge an aircraft in sight that has been pointed out by ATC, you are responsible from that point forward unless you advise ATC that you have lost contact. Initiate your avoidance procedure immediately, don't delay. Use a deliberate scan pattern in 15° segments of the windshield.
If you must react, it is important that you pre-decide what you are going to do. For example, turning tends to expose more of your aircraft to the other aircraft and the bank increases the G-load on the aircraft. My personal choice is to climb since this is the best reaction with birds who fold their wings and dive. As a reaction to aircraft the dive/ climb/choice might be best weighted as to which mode
gives you the strongest G-load margin. Higher positive G-loads exist over negative G-loads in aircraft construction and that would mean that diving would be best.
Responsibility for traffic avoidance under VFR rests solely on the pilot. ATC may or may not provide warnings. Once you acknowledge having seen traffic to ATC the full responsibility rests with you. Keep this traffic in sight. If you lose sight of acknowledged traffic, advise ATC. When using radar advisories, the tendency to relax vigilance, don't. ATC is not responsible for your collision avoidance except when IFR and then only from IFR traffic. This includes airport traffic patterns without radar, as well. Don't trust ATC to have cleared the direction of a commanded turn, takeoff or anything else. Clear areas for your safety. A clearance lets you do something when YOU think it is safe.
Only the exceptional pilot can visually locate and identify a traffic conflict from two miles. You are more likely to locate that traffic if you are so familiar with the area that the direction of where to look is known from a given pilot or ATC reference point. If you are unable to locate a pointed out aircraft at one mile the problem may relate to difficulty deciding where to look for eleven o'clock, an ATC point-out error, or the relative course movement. Any one of the three could amount to a 30-degree; aggregate error. For this reason you must scan. You scan by moving your head, not your eyes. You cannot see when your eyes move.
For a period of years, midair collisions have averaged in the low twenties per year. Only half of these result in fatalities. Half of mid-airs occur below 500' and 1/3 in the traffic pattern. The causes of these are inherent in the visual limits of the cockpit, the limitations of the human eye, and a concentration of aircraft at airports and navigational facilities. Flight below 3000' has inherent dangers since most aircraft are below that altitude much of the time. You can't see faster aircraft coming into you from behind and above. Aircraft climbing into you from below are more likely to see you. Fly at altitudes other than even thousands or five-hundreds when you are below 3000' AGL. Use radar assistance whenever it is available.
See and avoid has psychological effects decreasing visual effectiveness. If we 'see' an aircraft called by ATC we tend to stop looking for other aircraft. Small traffic over two-miles out will not be seen. Large traffic can be seen out to seven miles. Outside of one mile a pilot is unlikely to spot an aircraft. Limited visibility really means limited ability to see.
Traffic is what you see, what you hear is advisory only. A relatively high proportion of aircraft are not where they say they are when communicating to ATC or otherwise. By knowing where you are at all times, you can avoid being part of the problem. Make your radio calls accurate as to position, altitude and intentions. Stating your intentions is not a clearance for you to stop looking. An altitude call is more likely to be accurate than a position call.
The closing rate of most mid-airs is relatively slow since it is most likely a faster aircraft merging from the rear 10-degees off center to either side. It takes a minimum of 10 seconds for you to spot, identify, react, and have the aircraft move. At any merging speed over 700 knots you will not have time to move. Any aircraft on a collision course within three miles may well be unavoidable. Any aircraft on a collision course will be on the horizon and appear motionless. Such an aircraft will 'blossom' in your window at the last moment. Banking for avoidance will be less effective than a dive or climb.
--Organize your cockpit
--Clean the windows
--Follow the altitude flight rules
--Avoid crowed areas like near VORs
--Use your lights and strobes
--Keep your altimeter setting current
--Keep your visual scan coupled to your brain
--Visual complacency is a killer
--85% of preventable flight accidents are caused by deficiencies of judgment or attitude
The way to
use your eyes
The weak link in the see and avoid system is the eye. Dust, fatigue, feelings, illness, age, illusions, altitude, sun direction, glare, heat, lighting, and aircraft design affect vision. The eye has an accommodation function that enables it to change focus from far to near and back again. Even the best of eyes take one to two seconds to make this adjustment. If the weather or haze is significant the eyes may be unable to focus to a distance because there is nothing to see. You then have what is known as 'empty-field myopia'. If one eye sees something that the other eye cannot it gives a blurred or even rejected image to the brain. This happens when you have one eye dominant over the other. Movement is usually easily detected. While the eyes can get light from over 200° or arc, they can only focus on a 10-15-degree area. The eye can only focus while stopped. Move your eyes from side to side and you will only get a gray blur. Thus any scan must consist of a series of stops.
The system we practice is the one we will use. A good scan will make nine distinctive stops across the windshield with head turns to see to the rear at extreme left and right. Where you start is not as important as having a systematic method of looking. Drop the focus down and back up every third sweep to the flight panel and every fifth time to the engine/fuel panel. You must also move your head forward and back to see around the cabin posts and compass. No one scan works for everyone but the block scan that covers about nine sectors of the windshield is a good methodology. A fixation with a two-second stop is required to detect an existing target. You should devote 18 seconds to your external scan for every three seconds of cockpit scan. This means a 6 to l time difference, outside to inside.
Visual perception, as noted, is affected by many factors. An aircraft below you on final while you are on downwind may be lost in the mix of houses, trees and yards. Pilots tend to be optimistic and prone to overestimation of estimates of their visual abilities. Some people are entitled to this opinion however; Chuck Yeager was able to detect aircraft far sooner than other pilots of his WWII squadron were.
Scanning skill can reduce accidents that are expected by probability to happen every year. These thirty annual mid-air accidents can be reduced by seven or eight. We can learn to fly in those places and in such a way to bring about this reduction. Most midair collisions occur within five miles of an airport, below 3000' and in clear weather. Use standard 45-degree arrivals at uncontrolled airports. Learn to fly and practice where there are the fewest airplanes and the most space. As a student, do not stop clicking your eyeballs just because the instructor is aboard.
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.
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.
--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.
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.
Critical--where avoidance occurred only through chance.
--within 100 feet"
--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.
Violation of FARs
ATC separation error
Area of increased occurrence
Violation of movement area without authorization
---Radio position and intentions, when in doubt STOP
---Readback all instructions completely if not exactly
---Know runway and taxiway signage and markings
---Position and hold has inherent dangers…
---Clear both directions for all crossings
---Have airport ground map
---Use aircraft lights
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://www.faa.gov/and/and500/520/Programs/GM.html
Did not work well enough to be useful.
--82 percent of mid-airs occur from the rear.
--Scanning to the front and both sides cover only l5 percent of potential midairs.
--45 percent of accidents occur in the pattern.
--Low wing converging with high wing
--Faster aircraft overtaking slower aircraft
--On final at non-tower airport.
--En route inattention
--Taxiing on to active runway
Avoidance at Non-tower airports
--Know and use proper terminology for your position relative to airport or reference point.
--Tune, verify and use CTAF frequencies or get radar advisories.
--Make your first callup at least ten miles out and state your arrival intentions.
--Identify the airport at the beginning and end of every transmission.
--Ask if aircraft fails to give airport name or position.
--NORDO aircraft are both common and legal.
--Slow down to give yourself more time to react.
--Check behind and below at least once on final.
--Report your destination on departure. This is much more specific than just a pattern direction.
--Report IFR approach position by distance not fixes.
--All air-carriers are equipped with TCAS (Traffic Alert and Collision Avoidance Systems)
--Most MAC occur where most of planes are at airport below 500 feet.
--56 percent of MACs had fatalities
--60 percent of aircraft involved landed safely
--44 percent of the time, both planes landed safely
--80 percent of MACs occur with faster aircraft overtaking and converging from rear
--5 percent were from directly ahead
--50% of MACs pilots had over 1500 hours of flight time
--33 percent had over 3000 hours
--35.5 of MACs involve student pilots with 22.5 percent when solo and 28 percent with CFI aboard a plane
--No MACs have occurred in IFR conditions
Today, 10-7-03, my dumb son,
the half-Whitt that works for a living, sent me pictures of two F-18 that had
a head-on mid-air. One lost the entire fuselage forward of the
cockpit. The other lost part of one wing and part of vertical
stabilizer. Total value of the aircraft 80-million. Both landed
Avoiding the Midair
--Avoid congested airspace
--Don't overfly intersections or common call-up sites
--Stay away from military training routes (MTRs)
--Use strobes and flashing recognition lights
--Report your position accurately not as being over what you can see.
--Use flight advisories when in radar covered areas
--Use recommended radio and pattern procedures at non-towered airports
--We will continue to have the statistical probability of MACs just don't let it happen to you
to Recognize Conflicting Traffic
--Use a scanning technique that avoids distractions, fixation and blind spots
--Use series of fixated pauses of two seconds to allow eyes to focus
--Divide windshield into five blocks and focus in the center for distance
--Peripheral vision will detect motion
--10 degrees above and below horizon will detect most aircraft with MAC potential
--Use a 20 second scan pattern with three seconds for the instruments and 17 outside
--Vary your heading to create 'motion' in things you are trying to detect.
--Vary your aircraft attitude and seat position to reduce structural obstructions
--Use tinted glasses that will reduce the problems from sun and atmospheric situations
Being Situationaly Aware
--Make all your movements based upon knowing what other aircraft, vehicles and people are doing
--Use radio, signs, markings and lighting to orient yourself.
--At uncontrolled airports (NTA) all advisories should name airport twice; beginning and end.
--Listen to ATC advisories issued to other aircraft inbound and outbound
--Know and mark on diagram where you are now and draw out your route as cleared.
--Track your route in stages based on intersections and turns to destination
--Orally communicate with another or to yourself as progress continues
--Do not stop on a runway, get off if you can or at least to one side
--At NTAs make a full 360 while using the radio to advise of taking runway, departure and route.
--Do not go into the takeoff holding position unless certain the runway is clear
--Have someone check out the 6 o'clock to make sure no one is landing.
--Advise frequency that you are in position and holding.
--Confirm runway by reference to compass heading
--After landing turn clear of the runway as soon as possible.
--Do not let ATC force you into a premature turn.
--Taxi clear of the runway and across any hold bars before cleaning up aircraft.
--An advisory at a NTA that you are clear is not needed but won't hurt.
--General aviation aircraft averaged 27 per year.
--Forty percent of these ended without injury.
--Those involved in mid-air accidents were typically high-time pilots, averaging 3,000 hours.
--1/2 of mid-airs occur in California
–Over half of mid-airs involve high wing aircraft
–Less than half of the mid-airs involve low-wing aircraft
--49% of pilots in mid air accident have below 1000 hours.
--1/2 of mid-airs occur during instructional flight
--90% occurs during day time.
My Web Posting
This entire thread seems to be totally entranced with the possible conflict of aircraft on a heading/course. Whereas, the most likely conflict is in altitude between IFR and VFR supposedly flying with 500 feet of FAA separation.
Some time ago I was told that ATC figures a + - error 300 feet in blind encoder/transponder reply.. The altimeter is likewise allowed a 75 foot + - error. Not knowing for certain but assuming it is so. Look at the following scenario.
If we have an IFR and a VFR flying in opposite hemispheric directions in VFR conditions we have several possible extreme conditions. Take the first aircraft indicating 6000 feet west bound. The second aircraft indicating 5500 feet east bound. If both the transponders and altimeters have errors to the extreme in the opposite directions, they could still miss each other.
If the first aircraft is flying 250 lower than indicated due to accumulated instrument error, while the other is actually flying 250 feet higher than indicated we have only see and be seen to save the situation.
To me the probability of a midair is more likely to altitude error than heading error. The odds of having two such aircraft with hemispheric accumulative opposite errors in altitude sufficient to cause a midair is unlikely but more likely than an opposite heading midair. I believe this because the distances are matters of feet rather than miles. It takes both to actually cause the midair so the total emphasis on course/heading is only a part of the equation. I haven't even mentioned GPS altitude as a factor.
Helping Aircraft See You
One of my pet peeves in all uncontrolled airport departures as well as controlled airport departures is a failure of pilots to communicate beyond the airport and ATC. I do not like or teach straight-out, crosswind, downwind 270' departures. Rather, I teach 'on course'.
'On course...' to a specific location is even better than a magnetic direction since even locals have difficulty knowing the directions of their roads but do know where the roads go. By including the words 'on course' in your departure call you tell everyone on the frequency a line of flight as compared to the broad brush flight areas of the pattern. At a towered airport including a possible destination in your departure call you have 'filed' a mini-flight plan. At an non-towered airport you have greatly reduced the 'hot' traffic scan space for other pilots to see you. Try it, you'll like it.
With all due respect to others who disagree, I feel that pilots should
communicate their departure and arrival plans for the information of all who
may be on the frequency. I suggest using "... on course...as part of your
departure including final altitude call as being more definitive than westerly
or crosswind. I believe all calls, not at pattern altitude or on the ground,
should include altitude as well as the appropriate, level, climbing and
descending. The more help we get in finding traffic on the radio the better.
I teach my students to be suggestive rather than passive when talking with ATC.
Avoiding Arriving Aircraft
You will be amazed the number of times you will have airplanes slightly over and under you when you avoid all altitudes with three zeros or those with five and two zeros whenever within 3000'
of the ground.
Another survival device I teach is related to reporting points. Never report being at the reporting point. Fly so that you can say, "One North, South, East or West", of the reporting point' I gave a talk to the EAA so now I hear that a lot.
When weather is marginal, avoid the IFR approach corridors and remember in haze anything you see is closer than you think
Just yesterday ATC had three aircraft entering on right base for 32R at Concord. One was a C-150 that I often fly so I figured that with the Garmin 430 her reports were pretty accurate. The Piper was an unknown but in the vicinity. We were in my 180 hp+ C-172.
At one point we were off the right wing of the 150 but unable to find it. Never did see the Piper but knew that we were all in close proximity and heading for the same two mile base reporting point.
Three rounds of position reports along with altitudes failed to enable us to see the other aircraft. ATC had us on the BRITE to the right of the other aircraft. My pilot, a CFI to be, in the right seat informed ATC that we were making a right 360 for spacing and began the turn. when hearing no objection from ATC.
No doubt ATC would have worked out a solution if a collision was about to occur. I say, "Why wait for a situation to become critical before taking the safe way out."
When we landed ATC thanked us for our cooperation which included exiting at the first taxiway..
Mark I Eyeball
The Mark I eyeball is the most useful navigation aid when combined with the Mark I Outside World Indicator for identification of obstacles and other traffic.
Any object that maintains a constant relative position in relation to your eye is something that you will hit if it is approaching. So when you are on final approach and see an aircraft on a wide base out of the corner of your windshield, that stays in the same place and just seems to be getting bigger, you will have a collision on final with that airplane. If the airplane is moving toward the center of the windshield, it is changing the angle and is faster than you and IS in front of you. That does not give that aircraft the right of way (you're on final) but if he doesn't see you and you see him, avoidance is your responsibility. Just how close you'll come depends on speed changes.
Motionless objects are harder to see than objects with relative motion, so it isn't easy to see traffic that is most critical. To help see traffic and to help them see you, use all your lights, bank to see into your blind spots, don't fixate on the runway, clear the whole area. Look for shadows on the ground, some day you may see two or even three airplane shadows near you.
Keep all your windows clean, scratch free and clear of tickets.
James H. Macklin
Reasons You Can't See
Interesting article that has application in aviation outside of security screening. It might be a reasonably coherent explanation, for example, of why it is so difficult to pick out another plane from ground clutter, especially if the plane is of an unusual design.
Basically, the article discusses target-distractor similarity, where an object is difficult to identify from distracting objects of a similar appearance in the background, and the general problem of distractors, which make it difficult for the eye to recognize a familiar object if it is in an unexpected orientation or format. I think it could have particular application in explaining why student pilots have such difficulty picking out other aircraft or finding strange runways.
Target-distractor similarity could explain why otherwise intelligent pilots will attempt to land at Luke AFB instead of, say Glendale even though the pilot is familiar with both Glendale and Luke. They are not very similar, but when distracted by roads and other ground clutter a pilot can become temporarily disoriented. A closer example would be confusing Reid-Hillview with other area airports.
Clutter distraction would simply mean that it is harder to recognize another aircraft when it is flying over a cluttered background, such as an industrial area, than when it is flying over an even cloud cover or over water. It seems obvious, but consider what happens if you are told the aircraft is at 3:00 low, traveling in the same direction you are. You can look all over for an airplane, but miss the Long-EZ or helicopter that ATC is seeing.
If a bag screener has difficulty recognizing a gun simply because the image is reversed or in a different place from where he was used to looking for it, consider the problem of the pilot who is looking for another airplane that is "five miles out." Many pilots mis-report their position for a variety of reasons, but as shown by studies like this that can make you almost impossible to see.
An aircraft pulling out onto a runway for an intersection takeoff is another case. The pilot may look in only one direction, or if he looks both ways he is really only expecting traffic to come from one particular direction. If that is the case, he may not see an oncoming aircraft even though it is in plain sight. The eye sees it, but the brain does not register it. You get the same sort of effect when pulling into an intersection with a car. You expect traffic from the left and even if you look right you might not see a bicyclist riding on the left hand side of the road, despite his bright yellow jersey and florescent helmet. Even worse if he is on a sidewalk.
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