The importance of disaster investigations For Systems Engineers.

The importance of disaster investigations

For Systems Engineers

What is a Systems Engineer?

In the modern industry engineering systems are becoming more complex by the day. Therefore a need for elite engineers i.e. the Systems Engineer, capable of applying a wide range of engineering disciplines to a variety of tasks from product design and development from requirements analysis to simulation to manufacturing and marketing etc… is essential.

Such engineers work within a team at the heart of the organisation where the design and development of a project is carried out. At this stage it is of great importance that every aspect of the design is studied accurately in order to ensure the final product works effectively, efficiently and safely. However, although maximum effort is made during the design, it is impossible to produce a result 100% efficient. This unfortunately leads to the occurrence of accidents and in some extreme cases to a disaster. By carrying out investigations into the disasters and their causation, lessons can be learnt and employed in future designs. This allows the team of engineers to improve the performance and efficiency of the system whilst maintaining the maximum safety levels.

Disasters and why they happened?

Air disasters caused due to faulty design:

There have been historically countless cases of confusion in handling the flaps and the gear controls on the DC3 aircraft as they are in close proximity to each other and of similar shape. This is a problem that should have been addressed by the system engineers before the final go ahead for production was approved considering the importance of such instruments and their role during the flight of the aircraft.

Challenger disaster caused due to faulty design:

This incident saw the destruction of the United States space shuttle Challenger 73 seconds after take-off from the Kennedy Space Centre on January 28, 1986 killing the entire shuttle crew.

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Challenger disaster caused due to faulty design:

This incident saw the destruction of the United States space shuttle Challenger 73 seconds after take-off from the Kennedy Space Centre on January 28, 1986 killing the entire shuttle crew.

The disaster was caused by the failure of an “O-ring” seal in the solid-fuel rocket on the shuttle's right side. The seal's faulty design and the unusually cold weather, which affected the seal's proper functioning, allowed hot gases to leak through the joint. Flames from inside the booster rocket escaped through the failed seal and enlarged the small hole. The flames then burned through the shuttle's external fuel tank and cut away one of the supports that attached the booster to the side of the external tank. The booster broke loose and collided with the tank, piercing the tank's side. Liquid hydrogen and liquid oxygen fuels from the tank and booster mixed and ignited, causing the shuttle to tear apart.

It is quite clear from this example that had the design of the ring been suited to the environment in which it was to be used then such a disaster could have been prevented.

The Hillsborough disaster:

On the April 15, 1989 at the Sheffield Wednesday Football stadium the worst disaster in British sporting history took place. The match was a FA Cup semi-final between Liverpool and Nottingham Forest. The tragedy occurred when police opened a main gate into the terraced area to relieve pressures caused by a build up of people at the entrance allocated to the Liverpool supporters. This caused a flood into the packed terraces and people were crushed against the perimeter gates. In total 96 Liverpool fans lost their lives and another 400 were injured.

The cause of this disaster proved to be a combination of human error and faulty design. Primarily due to the poor and inefficient ground control and crowd management system, and secondly the existence of ground design faults which prevented the crowds from exiting the stands in the event of an emergency. As a result football stadiums are now designed without fences around the pitch and standing terraces have been abolished.

How do Systems Engineers learn from disasters?

We are now going to take a look at a disaster that has occurred in the past and see how this relates to the design cycle (Fig.1.1). By doing this, the importance of feedback from disaster investigations for systems engineers and how the information is incorporated will be illustrated.

We will use the Chernobyl disaster as an example to relate to the diagram.

April 26, 1986 saw the world’s worst known nuclear reactor disaster to date. The problem arose from an improperly supervised experiment conducted at a nuclear plant in a Ukrainian town, Chernobyl, located approximately 130 km north of Kiev. The experiment was undertaken with the water-cooling system turned off which led to an uncontrolled reaction, that in turn caused a steam explosion. The reactor’s protective covering was blown off, and approximately 100 million curies of radionuclides were released into the atmosphere. Some of the radiation spread across northern Europe and into Britain. Around 31 people died as a result of the accident, but the number of radiation-caused deaths is yet unknown although expected to be much greater.

Fig 1.1

The diagram above outlines the design and manufacturing process of the product. There are three main blocks i.e. the right hand corner shows the management aspect, the bottom right hand corner the operators (users) of the product and the left hand side is where the design and tests take place.

Systems engineers are situated in the design area and are involved with the organisations accumulated knowledge, process engineering, codes of practice and tests and reviews.

Relating this diagram to the Chernobyl disaster we can see that the problem originated in the operational management department. The approval of the experiment defied the organisations policies that no activity should been undertaken without proper supervision. This action from senior management allowed inexperienced staff to handle very dangerous equipment. With practically no training in operating or emergency procedures it was inevitable for disaster to strike. The operators proceeded with the experiment and due to a misunderstanding of the process instructions caused an explosion to take place that polluted the environment with nuclear radiation.

So how does this feedback affect the Systems Engineer?

From this example we can see that the main fault rested with the management section however the design and operating conditions of the equipment can also be taken into consideration.

The way the equipment operates could be modified in order to cater for human error. In this case for safety reasons for instance:

The set up of the machinery could be designed to satisfy a computer checklist before the reactor will function.
Another possibility could be the aid of a computer i.e. automation that would interact in the case of an emergency by either shutting down the system or making the necessary changes to other machinery.

These are just a couple of possible considerations that system engineers could bear in mind for future designs. Basically we are now not only having to design the system but also design it against possible short cuts that operators will take. Ignorance and human errors are aspects of life which may be controlled but never eliminated.

Designing to prevent:

To prevent disasters from happening there are a wide range of factors to take in to consideration as we have seen. The information from investigations has proved to be a crucial asset to the systems engineer whose responsibility is on going as these systems become more complex.

Unfortunately the best why we can prevent an incident occurring is by learning from someone else’s mistake.

Below is a short list of lessons learnt that hopefully will help engineers in the future during the designs process:

Primarily design for the environment and the operator, and secondly for the task.
Reduce the amount of stress inflicted on the individual as it has been shown that where high levels of stress exist, errors are more likely to occur.
Design against human short cuts that could possibly have disastrous effects.
Use feedback from previous events to modify future designs.
Ensure operating procedures and instructions exist and are understandable.
Staff must be trained in every aspect of their operating condition and in the event of an emergency should have a good understanding of safety procedures.
Ensure maintenance can be effectively carried out.
The conditions of the working environment will have a serious effect, for example a pilots performance will be effected if say the cockpit has improper lighting or if the control panels vibrate due to the aircraft’s propulsion.