The Nimrod Review - Official Documents

The Nimrod Review
462
The three year Dryden Inquiry presented a rare opportunity for an independent body
to examine the entire Canadian aviation system for organisational failures, both latent
and active, which might have contributed to the Captain’s faulty decision, and to make
recommendations for necessary change. It was an opportunity not to be squandered.” 16
18.13 The authors of Beyond Aviation Human Factors point that, even if pilot error had not occurred on this
occasion and the crash of Flight 1363 had not taken place, “…the flawed organisational processes and
the latent failures would still remain. Dryden would take place elsewhere, given the degree of sickness, the
numerous pathogens hidden in the system17 .
Accident Theories
18.14
There are two main accident theories:
18.14.1 Normal Accident Theory:
‘Normal Accident Theory’ holds that, when technologies become very
complex and ‘tightly coupled’, accidents become inevitable and therefore, in a sense, ‘normal’. 18
This theory takes a pessimistic, but not defeatist, view of the ability of organisations and individuals
to manage high risk technologies.
18.14.2 High Reliability Theory:
‘High Reliability Theory’ argues that organisations responsible for
operating high risk technologies can successfully compensate for inevitable human shortcomings
which would normally lead to catastrophic failures. Proper design, management and training are
seen as important requisites for being a highly reliable organisation.
Normal Accident Theory
18.15
Normal Accident theorists recognise that high-risk technologies are prone to accidents and catastrophes
when the right combination of circumstances come together to defeat safety devices and/or the efforts of
those responsible for coping with such events. The theory recognises the possibility of such events, rather
than being a statement of despair or “learned helplessness”. 19 However, Charles Perrow’s basic pessimism is
unmistakable:
“No matter how hard we try, no matter how much training, how many safety devices,
planning redundancies buffers, alarms, bells and whistles we build into our systems, those
that are complexly interactive will find an occasion where the unexpected interaction of two
or more failures defeats the training, the planning, and the design of safety devices.” 20
“If interactive complexity and tight coupling – system characteristics – inevitably will
produce an accident, I believe we are justified in calling it a normal accident, or a system
accident. The odd term ‘normal accident’ is meant to signal that, given the system
characteristics, multiple and unexpected interactions of failures are inevitable. This is an
expression of an integral characteristic of the system, not a statement of frequency…
System accidents are uncommon, even rare; yet this is not all that reassuring, if they can
produce catastrophes.” 21
16 See Address by The Honourable Virgil P Moshansky, CM QC – The Halifax 5 – Canadian Health Care Safety Symposium At Calgary, Alberta, Saturday
22 October 2005.
17 Ibid, page 81.
18 See the work of Charles Perrow, a leading proponent of the ‘Normal Accident Theory’.
19 James Reason.
20 Cited by Scott D Sagan in The Limits of Safety, 1993, page 45.
21 Charles Perrow, Normal Accidents – Living With High-Risk Technologies, 1984, page 4. (Princeton publishing).