April 20, 2019

Accident Investigation (2/2)

In the previous article, we discussed how the probability of accidents was listed. In this article, we will discuss how the possibilities are evaluated and how the conclusion is reached. Again, we continue with the mobile phone scenario and assume that the user died in the fire.

We reached the wreckage of the mobile phone in the fire site. The phone was shattered, and the pieces melted in the fire. Even though the device is in a very bad condition, it has a recording system that is strong enough to withstand all this damage. No matter what happens to the phone, nothing happens to this recording piece. This is the famous black box on the planes. The black box is a recording device. Usually, the last 25 hours of the flight, is constantly recorded with hundreds of different parameters. We can think of it as a digital camera that takes pictures from every direction of the entire plane, every second.

Imagine that our mobile phone is connected to our veins and just like the step gauge, it records our blood pressure & sugar level, heart rate, body temperature, frequency of breath, whether our stomach is full or not. If someone examine this recording, they could have an idea about us very quickly, right? For example, if the blood sugar has fallen and fainted, and we suspect that he was hitting his head, then we can see if he can see whether we're hungry or not. Or we could look at the direct blood glucose. We could examine what was the last time we had eaten.

The black box works in the same logic. It records the speed, weight, altitude, current weather conditions, fuel quantity, fuel consumption rate, engine rotation speed, exhaust temperature, oil temperature, wings, tail and landing gear position, and hundreds of different values. By examining these values ​​after an accident, weak possibilities are eliminated. The rest is put on the table and the finer recordings are used to make more precise eliminations. It takes a long time to get the final results. Because the wrong evaluations made in a hurry may cause different errors. Since the committees that make the evaluation have to be objective, they are formed by bringing together independent experts from different disciplines.

After all these evaluations, if all indicators indicate a single possibility, we determine the exact (100%) cause of the accident. However, if, despite all efforts, the cause cannot be reduced to a single probability, the result is declared with % probability. 70% likelihood due to the reason A, and 30% as likely to caused by B. So what happens after the conclusion?

The problem indicated by the final report is immediately taken into consideration on other aircraft.

Did the risk continue or was it an isolated event? On the other hand, the importance of the issue is published to all the aviation industry by renewing the warnings and precautions at necessary points.

If there is a risk of recurrence, a preventive solution is produced immediately. Repetitive checks are performed once or on planes of the same model that continue to fly. Routine maintenance coverage is expanded or detailed. New inspection and control methods can be made mandatory.

If there is negligence, the source is immediately identified and the necessary penal sanctions are applied. Depending on the extent of negligence, criminal penalties are introduced, ranging from fines to flying, to the cancellation of the company's trade license. Controls may be tightened or additional measures may be introduced so that neglect does not recur.

If the error is due to the design, the certificate specifications are updated. Similar criminal penalties come into play again. No one can be blamed if it has been found that there has been a situation that has never been seen before, because there has been a situation that cannot be foreseen despite all efforts without intent or negligence. Every kind of precaution is implemented in order to prevent repeating the required courses.

For example, the last Boeing 737 Max accident preventative solution could not be produced immediately, but the risk continued, so the airplanes' permission to fly was canceled. As of today, the investigation is still not finalized. Aircraft will not be able to return to commercial flights until the solution is finalized. We will see how much longer it will take and how it will end.

Aviation has come to these days with very painful experiences. No matter how painful the results were, the industry took the lesson out of every event and continued its path. We've already addressed an article about this in the title of How Safe Are the Airplanes?

The planes have affected our lives so deeply and significantly changed it. No matter how much it hurts us, it is impossible for us to separate our paths with them. Somehow, we will reach an agreement and move on to the future. The memories of the losses will always be with us and will be remembered in the history of civil aviation. Civil Aviation will become safer for all of us when the lessons that will brighten the future are brought to life.