AVIATION SAFETY NEWSLETTER
Thought for the month.......Knowledge of mid-air collisions is best not learned through experience.
Checklist for Avoidance....We just exceeded last year's number of mid-air collisions in the U.S. In 1999, we had 18. How high the number will be for 2000 won't be known for several weeks. That comes as a surprise to some people because they think of mid-air collisions as rare events. When you consider the fact that two aircraft are involved in each mishap, that means that 38 aircraft have already run into each other.
Electronic traffic collision avoidance systems (TCAS) are becoming more prolific and affordable. They are a good resource, but not a guarantee that a mid-air won't occur. Below 10,000 feet MSL, not all aircraft may show up on TCAS, and in high density areas, so many aircraft may be presented that a potential hazard can go unnoticed. We're getting better at it, but nothing has replaced the old Model 1 eyeball for seeing and avoiding other traffic.
Our eyes have a number of built-in problems that limit our ability to see. One of the most serious is the time required for accommodation. Accommodation is the process of refocusing from near to far objects, and back again. This can often take 2-3 seconds or longer depending on the lighting available. Add that to the average 10 seconds it takes to identify and react to a potential hazard and it becomes more understandable how two aircraft can try to occupy the same airspace at the same time. In addition to the built-in limitations, environmental properties can also severly restrict our vision. Precipitation, haze, darkness, bright sunlight, all effect our ablity to see the world around us. Three miles visibility may be legal VFR, but seeing other aircraft will be very difficult. The greatest limitation in all cases is however, our brain. If our mind isn't focused on seeing other traffic, our eyeballs will be of little use.
In developing a collision avoidance checklist the first consideration should be compliance with the rules and good operating procedures. In many in-flight collisions, at least one pilot was not where he was supposed to be. Since a number of mid-airs occur in the airport traffic pattern, knowing and complying with the established traffic patterns at an airport would be an excellent place to begin. This task has been made a lot easier recently by the addition of right pattern indications on sectional charts. If we have to unexpectedly divert to a strange airport, we don't need the additional stress of having to try to find the appropriate Airport Facility Directory to verify the pattern direction. All the information we need is on the chart.
The less time we have to spend inside, the more time we can spend looking outside. Having charts folded and in the proper sequence, organizing radio frequencies and GPS information, and keeping the cockpit free of clutter, will allow us to have some quality eyeballs-out time. Preflighting the airspace we will be operating in will help us identify landmarks and reporting points, as well as keeping us out of restricted areas or high density traffic areas. AFSS will know if MOA's are "hot". That is they know if the area is scheduled to be used, but they may not know if anyone is actually in there. To find out we need to contact the controlling agency, usually an Air Traffic Control Center, and that information is provided on the sectional. Since we're on the frequency anyway, might as well request flight following, at least while we're near the MOA.
We need the be aware of the design characteristics of the aircraft we are flying and compensate for blind spots. What is the proper initial control input for a left turn in a Cessna 172? - Right aileron. We need to compensate for the high wing design by raising the wing for a moment so we can clear the area we will be turning into. We should spend some time removing self induced problems also. A dirty, scratched, or bug spattered windscreen will make finding traffic even more difficult. Having a clean windscreen is great for us, but turning on strobes and landing lights will help us become more visible to other pilots who might not have taken the time to be as cautious. We might not have TCAS installed in the aircraft we're flying, but ensuring our transponder is "on" will make us show-up for operators that do.
When approaching airports with ATIS, that information should be received as early as possible. The closer and lower we get, the more time we need to spend looking outside, not copying information. Being aware of which runways are in use may also change the way we arrive in the area, making pattern entry easier. Knowing the CTAF or the tower frequency and monitoring the frequencies as we approach the airport will help give us a mental picture of the activity we may expect. Enter traffic patterns at traffic pattern altitude. Never descend into a pattern, that's a sure formula for disaster.
The most important item on our checklist is, of course, to scan. Despite their limitations, our eyes provide us with color, beauty, shape, motion, and excitement. As we train them to look for traffic in the sky, we also improve our ability to appreciate the view from aloft. Develop a plan for scanning and use it all the time. Knowledge of mid-air collisions is best not learned through experience.
Florissant Valley Community College
Student Center Building
AOPA Air Safety Foundation
Spectrum Balloon Port
Balloon Instructor Refresher Clinic
Boeing Building 33
McDonnell and Lindbergh Blvds
St. Louis and Southern Illinois Super Safety Seminar
8AM to 1PM
LET'S NOT MEET BY ACCIDENT
FRED P. Harms
Operations Safety Program Manager
1-800-322-8876 extension 4835