The “accident pyramid”, as depicted by H. Heinrich in the second edition of his book Industrial Accident Prevention: A Scientific Approach. Note the last sentence: “Moral — prevent the accidents and the injuries will take care of themselves”.
F. Bird’s work revealed the following ratios in the accidents reported to the insurance company:
For every reported major injury (resulting in a fatality, disability, lost time or medical treatment), there were 9.8 reported minor injuries (requiring only first aid). For the 95 companies that further analyzed major injuries in their reporting, the ratio was one lost time injury per 15 medical treatment injuries.
The safest way to operate in any industry is to eliminate all hazards. Unfortunately, this is a virtually impossible task since the cost of such an operation would be prohibitive. The effort required to run such a system will make it inviable in every sense. A Safety Management System (SMS) is a systematic approach to managing safety, including the necessary organizational structures, accountabilities, policies and procedures. As per ICAO requirements, service providers are responsible for establishing an SMS, which is accepted and overseen by their State.
Prior to implementation of the ICAO Annex 19 SMS, the regulations were more prescriptive. One could either perform an action or not, it was black or white. With the implementation of the SMS, actions can be performed if the risk generated is acceptable interns of the product of frequency and probability. Therefore, if the SMS program is fully implemented, then risk based decisions could be taken. The SMS program would keep a track of the risk to ensure that it does not exceed the limits set by the system through a process of feed back and periodic review. Training of personnel and effective reporting through a healthy safety culture would make the system more robust and effective.
A typical safety risk analysis of Spice Jet operations would reveal the risk level as 5C due to the high frequency of major occurrences. This would typically entail immediate mitigating action by the operator/regulator or restrict operations. These measures are required to ensure that the operator gets their act together and ensures that the safety management system is working and more importantly effective.
Note: The above table is not based on actual data but indicative of a likely scenario.
Decision errors: These “thinking” errors represent conscious, goal-intended behavior that proceeds as designed, yet the plan proves inadequate or inappropriate for the situation. These errors typically manifest as poorly executed procedures, improper choices, or simply the misinterpretation and/or misuse of relevant information.
Skill-based errors: Highly practiced behavior that occurs with little or no conscious thought. These “doing” errors frequently appear as breakdown in visual scan patterns, inadvertent activation/ deactivation of switches, forgotten intentions, and omitted items in checklists. Even the manner or technique with which one performs a task is included.
Perceptual errors: These errors arise when sensory input is degraded, as is often the case when flying at night, in poor weather, or in otherwise visually impoverished environments. Faced with acting on imperfect or incomplete information, aircrew run the risk of misjudging distances, altitude, and descent rates, as well as of responding incorrectly to a variety of visual/vestibular illusions.
Routine violations: Often referred to as “bending the rules,” this type of violation tends to be habitual by nature and is often enabled by a system of supervision and management that tolerates such departures from the rules.
Exceptional violations: Isolated departures from authority, neither typical of the individual nor condoned by management.
The question which arises is, if the root cause of most errors/violations is the human being then isn’t it better to fix the cause rather than creating engineering controls for every error that the human makes? It is important to determine why normal procedures failed to work or the reasons for failure of standard operating procedures to trap the error or error prevention. it will be more fruitful to concentrate our effort on revising the SOP’s and retraining humans to ensure behavioral control.