Aviation safety issues and actions

Turbine blade material susceptible to creep rupture

Issue number: AO-2009-069-SI-01
Who it affects: Operators of aircraft fitted with CFM56 engines
Issue owner: CFM International
Transport function: Aviation: Other
Background: Investigation Report AO-2009-069
Issue release date: 20 July 2011
Current issue status: Adequately addressed

Safety issue description

Material characteristics of some the LPT blades installed in engine 858322 were consistent with a raw material manufacturing cast that had previously been identified as being susceptible to creep rupture

Proactive Action

Action number: AO-2009-069-NSA-090
Action organisation: CFM International
Date: 20 July 2011
Action status: Closed

As a result of this occurrence and at the time of writing this report, the engine manufacturer is revising service bulletin SB 72-1113 to expand the range of blade manufacturing batch numbers that had previously been identified as being predisposed to creep-related failure.

Blades in the batches identified in the service bulletin are to be withdrawn from service as soon as they are next removed from the engine.

ATSB comment:

Adequately addresses the issue until such point as there are more, unrelated occurrenecs.

Last update 24 February 2014