Document ID: chunk:federal_register_of_legislation:F2008L01253:body:0:p2
Version: federal_register_of_legislation:F2008L01253
Segment Type: other
Provision Reference: 
Character Range: 2856–4598

Amdt 15349 dated 16 January 2008 refers.

Compliance:     1. For TFE731-2C, -3B, -3BR, -3C, -3CR, -3D, -3DR, -4R, -5AR, -5BR, and -5R series turbofan engines use the following drawdown schedule:

                  a. For HP turbine discs with 4,200 cycles-since-new (CSN) or more on the effective date of this AD, remove HP turbine rotor assemblies within 100 cycles-in-service (CIS) after the effective date of this AD.

                  b. For HP turbine discs with fewer than 4,200 CSN on the effective date of this AD, remove HP turbine rotor assemblies at the next access to the HP turbine rotor discs, but not to exceed 4,300 CSN.

                2. For TFE731-20R, -20AR, -20BR, -40, -40AR, -40R, and -60 series turbofan engines use the following drawdown schedule:

                  a. For HP turbine discs with 3,200 CSN or more on the effective date of this AD, remove HP turbine rotor assemblies within 100 CIS after the effective date of this AD.

                  b. For HP turbine discs with fewer than 3,200 CSN on the effective date of this AD, remove HP turbine rotor assemblies at the next access to the turbine rotor discs, but not to exceed 3,300 CSN.

                3. From the effective date of this AD.
             This Airworthiness Directive becomes effective on 8 May 2008.
Background:  This AD results from the manufacturer's report that some HP turbine rotor discs received improperly machined radii in the root of the forward and aft curvic teeth during manufacture.  The issuing of this AD is intended to prevent uncontained failure of the HP turbine rotor assembly, which could result in damage to the aeroplane.

David Punshon
Delegate of the Civil Aviation Safety Authority

6 March 2008