4.9Propulsion System

4.9.1 The air operator's assessment of propulsion systems reliability for the ETOPS fleet should be made available to their PMI (with supporting data) in accordance with an agreed upon frequency, to ensure that the approved maintenance program continues to maintain a level of reliability necessary for Extended Range Operations.

4.9.2 The assessment will include, as a minimum, engine hours flown in the period, in flight shut-down rate for all causes and engine removal rate, both on a 12 month moving average basis. Where the combined ETOPS fleet is part of a larger fleet of the same aircraft/engine combination, data from the air operator's total fleet will be acceptable. However, the reporting requirements of paragraph4.7 of this Chapter must still be observed for the ETOPS fleet.

4.9.3 Any adverse sustained trend shall require an immediate evaluation to be accomplished by the air operator in consultation with the PMI. The evaluation may result in corrective action or operational restrictions being applied.

Note: Where statistical assessment alone may not be applicable, e.g. when the fleet size is small, the air operator's performance will be reviewed on a case-by-case basis.

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