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Old 20th Mar 2009, 07:58
  #1294 (permalink)  
JimL
 
Join Date: May 2003
Location: Europe
Posts: 900
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maxwelg2,

Although not apparently a cause of this accident, perhaps your mind can be set at rest when it comes to events in the CADORS data-base that are concerned with engine-failure.

It might be of interest to know that all (world-wide) engine failures are tracked as a result of the JAR-OPS 3 requirement to establish engine reliability. Each Type Certificate Holder (TCH - engine and airframe) is required to log and investigate all in-flight-shut-downs (IFSD) - commanded (perhaps as a result of a chip warning) and uncommanded (when the engine power drops below a defined level). The requirement for analysis is contained in Appendix 1 to JAR-OPS 3.517(a) with methods of compliance in ACJ-1 to Appendix 1 to JAR-OPS 3.517(a).

Each IFSD is investigated by the appropriate TCH and an applicability (to reliability) factor is assigned; as you can imagine, failures that are due to (say) FOD are not considered to have a high relevance but those which result from failure of some (part of a) unit are. For each of these events there is a corrective action (and/or comments); each of these corrective actions is assessed for 'efficiency of corrective action' which can then be applied to the reliability index. (No failure escapes this analysis.)

The subsequent reliability index must be within a target (set in the regulations mentioned above) before that aircraft can be approved for use by operators in certain types of operation - flight over hostile environments like the North Atlantic or the North Sea for example.

Each airframe manufacturer is required to assess its airframe/engine combinations yearly and provide the results of this analysis - the index to operators (in the form of an AOL) and analyses to the Authority of the State of the Operator. In order that the index is smoothed, a moving statistical window of five years is used.

Sikorsky released the latest result of this analysis to operators, in the last month. The latest (five year) index was below (better than) the target set in the regulation.

Jim
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