International Helicopter Safety Team Safety Management System Toolkit

Investigation
Occurrence, incident & accident:
Occurrences are unplanned safety related events,
including accidents and incidents that could impact
the safety of guests, passengers and personnel, equipment
or the work environment.
Every occurrence, incident or accident is investigated
for the purpose of gathering information to help
prevent similar occurrences. An initial risk assessment
assists in determining the extent of the full investigation.
Reports that demonstrate a high potential hazard
should be investigated in greater depth than those
with low potential. The investigation and analysis
results do the following:
Determine “what” and “why” the event happened,
rather than, “who’s” to blame
Ensure the person(s) conducting the investigation
is technically qualified and has access to other
personnel with expertise that may assist with the
investigation
Identify immediate causal and contributing factors
Look at organizational factors that may exacerbate
the hazard or incident
Identify both acts of “omission” and “commission”
Provide a report to the manager with the authority
to implement recommendations
In aviation incidents, injury and damage are generally
less significant than in accidents. In principle,
more information regarding such occurrences should
be available, e.g. live witnesses. Without the threat of
substantial damage and injury lawsuits, there tends to
be a less adversarial atmosphere during the investigation.
Thus, there should be a better opportunity to identify
why the incident occurred and how the defenses in
place prevented them from becoming accidents. In an
ideal situation, the underlying safety deficiencies could
all be identified and preventive measures implemented
before an accident occurs. (See the Occurrence &
Hazard I.D. Report form on the page 52.)
The 600 Rule
Research into industrial safety in 1969 indicated
that for every 600 events reported with no
injury or damage, there were:
30 involving property damage
10 involving serious injuries
1 fatal injury
The ratio shown in the below figure is indicative
of a wasted opportunity if investigative efforts are
focused only on those rare occurrences where
there is serious injury or significant damage.
...But Events are Precursors to Accidents
SMS Toolkit 51