Document ID: chunk:federal_register_of_legislation:F2005L01791:body:0:p6
Version: federal_register_of_legislation:F2005L01791
Segment Type: other
Provision Reference: 
Character Range: 15722–18896

At the next gearbox inspection, engine overhaul, or when the gearbox diaphragm module is out of the engine, whichever occurs first after the effective date of this Directive.

             Requirement 6(a)(i):  At intervals not to exceed 9,000 hours TIS since the last replacement of the bull gear, P/N 3108295-1, and the HSP, P/N 3101741-2, or since the last overhaul of the diaphragm matched housing set, whichever occurs first.

             Requirement 6(a)(ii):  Whenever certain gearbox parts, identified in Paragraph 2.B. of ASB TPE331-A72-2088, are removed from the engine following compliance with Requirement 6(a) or 6(b)(i) of this Directive.

             Requirement 6(a)(iii):  Whenever the engine is removed from the aircraft and disassembled to the extent that the diaphragm module is accessed after 500 hours TIS following compliance with Requirement 6(a) or 6(b)(i) of this Directive.

             TPE331-12JR Engines

             Requirement 7(a):  At the next gearbox inspection, engine overhaul, or when the bull gear requires replacement, whichever occurs first.

             Requirement 7(b)(i):  At intervals not to exceed 5,100 hours TIS since the last replacement of the bull gear, P/N 3108295-1, and the HSP, P/N 3101741-2, or since the last overhaul of the diaphragm matched housing set, whichever occurs first.

             Requirement 7(b)(ii):  Whenever certain gearbox parts, identified in Paragraph 2.B. of ASB TPE331-A72-2093, are removed from the engine following compliance with Requirement 7(a) or 7(b)(i) of this Directive.

             Requirement 7(b)(iii):  Whenever the engine is removed from the aircraft and disassembled to the extent that the diaphragm module is accessed after 500 hours TIS following compliance with Requirement 7(a) or 7(b)(i) of this Directive.
             This Amendment becomes effective on 4 August 2005.
Background:  This Directive supersedes AD/TPE 331/55 Amdt 3, AD/TPE 331/57 Amdt 1 and AD/TPE 331/58 Amdt 2.  Those Directives were in response to failure of reduction gears in TPE 331 -11 and -12 model engines.  Those Directives required certain parts to be replaced and inspection of the affected parts to prevent further failures from occurring.

             Since mandating the requirements of the above mentioned Directives there have been further failures involving engines, both locally and overseas.  In response to those failures the manufacturer has released a new bull gear, high-speed pinion and diaphragm assembly that have been designed to address the current problems.

             This Directive also provides an alternative to mandatory requirements by approving the use of the manufacturers referenced service bulletins as an alternative to both the compliance times given and the requirement to replace certain parts with other parts for certain model engines.  The fitment of the new designed parts will provide terminating action for the repetitive inspections detailed in this Directive.

             Amendment 1 includes an alternative means of compliance for TPE 331-12JR engines.  There have been no other changes to the requirements for other models of the