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Figure 21: Fatal and All Accident Rates per 100,000 Flying Hours
0
1
2
3
4
5
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
Accident Rate per 100,000 Flying Hours
Annual Fatal Accident Rate
Annual All Accident Rate
Five-Year Average Fatal Accident Rate
Five-Year Average All Accident Rate
Source: Oil & Gas UK
4.4 Accident Analysis
A breakdown of reportable accident causes from 1997 to 2016 is provided in the charts overleaf
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. From 1997
to 2016, operational causes (flight and ground) accounted for 38 per cent of accidents, 38 per cent were due to
technical failures and 24 per cent caused by external factors.
All the operational accidents that occurred during flight were attributed to pilot error. Eighty-eight per cent of the
technical failures were attributed to dynamic component failures (main rotor gear box, main rotor blade and tail
rotor). A structural issue accounts for the remaining 12 per cent.
For the 24 per cent of accidents due to external factors, all resulted from weather-related events, including four
lightning strikes and an encounter with a water spout.
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For accident events to be identified using a recognised international code, categorisation and causation follows the
International Civil Aviation Organisation/Commercial Aviation Safety Team Common Taxonomy Team Taxonomy.
Operational (F) = an event related to the helicopter while in flight or abnormal contact with terrain.
Operational (G) = an event related to the helicopter while on the ground.
Technical = an event involving system/component failure or malfunction, fire/smoke.
External = an event involving icing, turbulence, wind shear, thunderstorm or bird strike.
4