Commonwealth legislation

AD/CT7/10 Amdt 2 - Propeller Gearbox(PGB)

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

4/10 complexity

This Airworthiness Directive requires operators of specific General Electric CT7 turboprop engines with listed propeller gearboxes to inspect the propeller gearbox (PGB) oil-filter impending bypass button for extension, and to replace specified left and right idler gears or the entire PGB in certain cases. CASA explains the measures are intended to prevent idler-gear separation that can cause uncontained gearbox failure and impair propeller feathering. The rule affects aircraft operators and maintenance organisations that must follow the stated inspection intervals and GE service bulletin instructions.

JSON API

Deep dive

Want the full deep dive?

Zoe can write the in-depth analysis on top of the summary above: how it works, who it affects and what each part actually does.

Current sections

Direct links to the current provisions in AD/CT7/10 Amdt 2 - Propeller Gearbox(PGB).

AD/CT7/10 Amdt 2 - Propeller Gearbox(PGB)

View image in the official source

View image in the official source
AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/CT7/10 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

View image in the official source

General Electric Turbine Engines - CT7 Series

AD/CT7/10

Amdt 2

Propeller Gearbox(PGB) 7/2004

Applicability: General Electric Aircraft Engines (GEAE) CT7 series turboprop engines with propeller gearboxes (PGBs) identified by serial number (SN) in Table 1 of GEAE CT7 Turboprop Service Bulletin CT7-TP S/B 72-0452, dated 27 July 2001, and Table 1 of GEAE CT7 Turboprop Alert Service Bulletin (ASB) CT7-TP S/B 72-A0466 dated 17 April 2003. These engines are installed on, but not limited to, SAAB 340 series aeroplanes.

Requirement: 1. Inspect the propeller gearbox (PGB) oil filter impending bypass button (IBB) for extension. If PGB oil filter IBB is extended, replace the oil filter and carry out inspections in accordance with 3.A of the Accomplishment Instructions contained in GEAE CT7 Turboprop Service Bulletin CT7-TP S/B 72-0453,dated 27 July 2001.

2. Replace left and right-hand idler gears in accordance with the Accomplishment Instructions GEAE CT7 Turboprop Service Bulletin CT7-TP S/B 72-0452, dated 27 July 2001.

3. If the PGB is mated to a Hamilton Standard propeller and the left and right-hand idler gears have not been replaced in accordance with the Accomplishment Instructions contained in GEAE CT7 Turboprop Service Bulletin CT7-TP S/B 72-0452,dated 27 July 2001, replace the PGB.

Note: FAA AD 2004-07-09 Amdt 39-13553 refers.

Compliance: For Requirement 1: Unless previously accomplished, initial inspection within 50 hours time-in-service (TIS) after the effective date of this AD and thereafter on each day of aircraft operation until compliance with Requirment 2 or 3 of this Directive is achieved.

For Requirement 2: At next workshop visit of the PGB after the effective date of this AD.

For Requirement 3: Before accumulating an additional 2,000 engine flight hours after the 6 August 2003, the effective date of amendment 1 of this Directive.

This Amendment becomes effective on 8 July 2004.

General Electric Turbine Engines - CT7 Series

AD/CT7/10 Amdt 2 (continued)

Background: This AD is prompted by an on-going investigation that concluded that low-time PGB removals are due to accelerated wear of the PGB idler gears, rather than improperly hardened PGB input pinions. The actions specified in this AD are intended to prevent separation of the PGB left and right-hand idler gears, which could result in uncontained PGB failure and internal bulkhead damage, possibly prohibiting the auxiliary feathering system from fully feathering the propeller on certain PGB’s.

Amendment 1 clarified the applicability and, for administrative reasons, brought forward the effective date by one day.

This amendment includes additional PGB and PGB gears as detailed in the reference documents. There are no changes to the inspection requirements.

Signature of James Coyne Delegate of the Civil Aviation Safety Authority

James Coyne

Delegate of the Civil Aviation Safety Authority 28 May 2004

View image in the official source

The above AD is notified in the Commonwealth of Australia Gazette on 16 June 2004.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/CT7/10 Amdt 2 - Propeller Gearbox(PGB)

AIRWORTHINESS DIRECTIVE

General Electric Turbine Engines - CT7 Series

AD/CT7/10

Amdt 2

Propeller Gearbox(PGB) 7/2004

2. Replace left and right-hand idler gears in accordance with the Accomplishment Instructions GEAE CT7 Turboprop Service Bulletin CT7-TP S/B 72-0452, dated 27 July 2001.

3. If the PGB is mated to a Hamilton Standard propeller and the left and right-hand idler gears have not been replaced in accordance with the Accomplishment Instructions contained in GEAE CT7 Turboprop Service Bulletin CT7-TP S/B 72-0452,dated 27 July 2001, replace the PGB.

Note: FAA AD 2004-07-09 Amdt 39-13553 refers.

For Requirement 2: At next workshop visit of the PGB after the effective date of this AD.

For Requirement 3: Before accumulating an additional 2,000 engine flight hours after the 6 August 2003, the effective date of amendment 1 of this Directive.