U.S. Department
of Transportation

Federal Aviation

St. Louis
Flight Standards District Office

10801 Pear Tree Lane
Suite 200
St. Ann, Missouri 63074


October 2000 




Thought for the month.....When we try to separate one thing by itself we find it hitched to everything else in the universe.

Identifying Links.... We have been taught that an accident is usually the product of a chain of events, and that if we intervene at some point and remove a link in the chain an accident will be prevented. That's sort of true, but it assumes that we can identify the error links. Secondly, it assumes that the same chain of events will always produce an accident. And, lastly, it discounts the fact that modifying the chain might actually be the last necessary step to cause the accident to occur.

When we investigate an accident we attempt to find as many links in the error chain as we can, and then try to figure out where they fit. It becomes clear very quickly that the same set of conditions may exist time and time again without causing an accident. For example, a pilot may experience a door popping open on several occassions and deal with it without incident. Then, the event occurs again and the pilot becomes preoccupied by it and loses control of the aircraft. Same aircraft, same pilot, same event. Three times it's handled successfully, but the fourth time it causes a fatal accident. What changes in the error sequence caused the final event to end tragically? Is it really possible to identify the links in the chain and correct them before the accident?

My favorite cartoon which I collected during the days when I was flying military aircraft, depicts a character looking very much like a visitor or sightseer, standing before three huge pipes sticking out of the ground. The sign which he is staring at reads: "The tubes down which many things have gone." I've seen those tubes, and watched many plans go down them. When that happened, it usually meant that we were making up a new plan as we went along. Deviation from the plan is always one of the first links in an accident chain, and is even more so when the "new plan" includes procedures which are contrary to existing rules or directives.

One of the reasons a plan goes down the tubes is because of disparity or difference from what is supposed to happen, versus what actually happens. We were expecting A, we were prepared to deal with B, and had considered the possibility of C happening. What we got was Q with no idea how to make that work. The fact that A,B,& C have gone down the tubes is not necessarily the critical link, but because our original plan has now evaporated, we can become preoccupied with alternatives. We can also become fixated on a particular element and miss critical information.

All these things inevitably lead to a condition of uneasiness. Sometimes we call this premonition or just gut feeling, and it is often one of the most easily identifiable links in a mishap chain. Confusion usually accompanies the uneasiness, causing us to feel more like we're along for the ride, instead of directing the action.

Sometimes, just the realiztion that some of the above conditions exist is sufficient to prevent a mishap. Perhaps the most critical link in the accident chain is the failure to recognize, or admit, that a change has occurred. The pilot had experienced the door popping open on several occassions without disasterous results. When it happened again he may have become preoccupied in trying to find out why the door kept popping open. He didn't recognize it as an initiating event and that may have been the key difference between the last tragic time it happened, and the previous occurrences.

Rarely does a flight go exactly as planned. When changes occur, recognition and heightened awareness may be the best tools at our disposal. We may not know everything that's going on, but at least we realize it isn't going as planned. An accident is a chain of events, but it is over simplifying it to say that we can identify the critical one's and remove them. Removing a link might just be the element that causes the mishap. When we try to separate one thing by itself we find it hitched to everything else in the universe.

AFSS Operation Takeoff dates....The St. Louis AFSS is offering pilot education seminars, and facility briefing and tour for groups of 15 people on the Oct. 21 and Nov. 18, from 9am to noon. Reservations are required and can be made by calling Lisa Burrows at 314-890-7210.

Upcoming Events

Oct. 10
The St Louis Chapter is proud to present
Weather Wise
Lindbergh High School
7pm to 9pm
Check our October page for directions:

Oct. 21
Marriott West Hotel, Town & Country MO
Helicopter Safety Seminar
8am to 1pm

Oct. 26
Creve Coeur Aviation
Creve Coeur Airport
Operations at Non-towered Airports and Land Survival
7pm to 9pm

Oct. 27
Schafer Metro East Airport, St. Jacob, IL
Cockpit Complacency, Disorientation and Vertigo
7 to 9pm

Nov. 9
Cape Girardeau Airport
Cape Pilots Club Bldg.
Aeronautical Decision Making and Disorientation and Vertigo
7 to 9pm.

FRED P. Harms
Operations Safety Program Manager
1-800-322-8876 extension 4835