AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 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.
Allison Turbine Engines - 250 Series
AD/AL 250/81 Third Stage Turbine Wheels 6/2002
Applicability: Allison 250 - C28 Engines with third stage turbine wheels Part Number (P/N) 6899383 and with Serial Numbers (S/N) listed in Table 1 of this Directive.
Requirement: Remove from service all turbine wheels P/N 6899383 listed by S/N in Table 1 of this Directive.
Note: FAA AD 2002-06-08 refers.
Compliance: Effective 13 June 2002; as per Table 2 of this Directive.
This Airworthiness Directive becomes effective on 13 June 2002.
Background: Fractures of the third stage turbine blade tips and shrouds could cause uncommanded shutdowns. New lower life limits have been established to address this problem.
This Directive requires the removal from service of certain turbine wheels that exceed the new lower life limits.
Table 1. S/N’s of Affected Third Stage Turbine Wheels
HX91428R | HX91489R | HX91707R |
HX91456R | HX91490R | HX91708R |
HX91457R | HX91492R | HX91709R |
HX91428R | HX91489R | HX91707R |
HX91456R | HX91490R | HX91708R |
HX91457R | HX91492R | HX91709R |
HX91458R | HX91493R | HX91710R |
HX91459R | HX91494R | HX91711R |
HX91461R | HX91500R | HX91712R |
HX91462R | HX91501R | HX91713R |
HX91464R | HX91503R | HX91714R |
HX914659 | HX91504R | HX91715R |
HX91465R | HX91506R | HX91721R |
HX91466R | HX91507R | HX91722R |
HX91467R | HX91508R | HX91726R |
HX91468R | HX91510R | HX91733R |
HX91469R | HX91511R | HX91735R |
HX91471R | HX91512R | HX91736R |
HX91472R | HX91513R | HX91738R |
HX91473R | HX91519R | HX91742R |
HX91474R | HX91520R | HX91744R |
HX91475R | HX91522R | HX91748R |
HX91477R | HX91523R | HX91749R |
HX91478R | HX91524R | HX91750R |
HX91480R | HX91525R | HX91754R |
HX91482R | HX91526R | HX91764R |
HX91483R | HX91527R | HX91765R |
HX91485R | HX91528R | HX91766R |
HX91486R | HX91529R | HX91767R |
HX91487R | HX91530R | HX91768R |
HX91488R | HX91706R | HX91769R |
Table 2. Removal Schedule
As of the effective date of this AD | Remove by |
(1) With fewer than 2,800 cycles-since- new (CSN), and fewer than 1,400 hours’ time-since-new (TSN). | 3,000 CSN or 1,500 hours TSN, whichever occurs earlier. |
(2) With between 2,800 and 3,000 CSN (inclusive), and fewer than 1,500 hours TSN. | 200 additional cycles or 100 additional hours, after the effective date of this AD, whichever occurs earlier. |
(3) With fewer than 3,000 CSN, and between 1,500 and 3,000 hours TSN. | 100 additional hours, after the effective date of this AD. |
(4) With between 3,000 and 6,000 CSN (inclusive), and fewer than 1,500 hours TSN. | 200 additional cycles, after the effective date of this AD. |
(5) With between 3,000 and 6,000 CSN and between 1,500 and 3,000 hours TSN. | 200 additional cycles or 100 additional hours, after the effective date of this AD, whichever occurs earlier. |
(6) With more than 6,000 CSN, or more than 3,000 hours TSN | Before further flight. |
James Coyne
Delegate of the Civil Aviation Safety Authority 15 April 2002
The above AD is notified in the Commonwealth of Australia Gazette on 22 May 2002.
Overview
The Civil Aviation Safety Authority (CASA) introduced Airworthiness Directive (AD) AL 250/81 on 13 June 2002 to address safety concerns associated with fractures in the third stage turbine blades and shrouds of Allison 250-C28 engines. This AD aims to mitigate the risk of uncommanded shutdowns by requiring the removal of certain turbine wheels that have exceeded the newly established lower life limits. The directive applies to Allison 250-C28 engines with third stage turbine wheels Part Number (P/N) 6899383 and specific Serial Numbers (S/N) listed in Table 1 of the directive. The policy objective is to enhance aviation safety by ensuring that affected turbine wheels are removed from service to prevent potential engine failures. Compliance with this directive is mandatory, with removal schedules outlined in Table 2, varying based on the cycle and time since new of the affected turbine wheels.
Scope and Application
This Airworthiness Directive (AD) issued under the Civil Aviation Regulations 1998 by a delegate of the Civil Aviation Safety Authority (CASA) pertains specifically to Allison 250 - C28 engines equipped with third stage turbine wheels with Part Number (P/N) 6899383 and particular Serial Numbers (S/N) as listed in Table 1 of the Directive. The AD mandates the removal from service of these specific turbine wheels, which have been identified as potentially unsafe due to the risk of fractures leading to uncommanded shutdowns. The geographic reach of this AD is the Commonwealth of Australia, as CASA is a federal authority. The AD applies to aircraft operators who possess or use the specified engines and must comply with the outlined removal schedule in Table 2. The Directive does not specify any exclusions or exemptions, and it extends its application through subordinate instruments where necessary, ensuring the safety and airworthiness of the specified aircraft engines within Australia.
Key Provisions
The Airworthiness Directive (AD) AD/AL 250/81, issued by the Civil Aviation Safety Authority (CASA) delegate, targets the Allison 250 - C28 engines with specific third stage turbine wheels identified by part number 6899383 and the serial numbers listed in Table 1. This AD mandates the removal of these turbine wheels from service to address safety concerns related to potential fractures in the third stage turbine blade tips and shrouds, which could lead to uncommanded shutdowns. The requirement (section 3) is to remove the specified turbine wheels from service, with the effective date set for 13 June 2002, as outlined in section 4 of the directive. The compliance section (section 5) provides a schedule for the removal of the turbine wheels based on their cycles since new (CSN) and time since new (TSN), with different timelines depending on the specific conditions of the turbine wheels.
Entities governed by this AD, particularly those operating Allison 250 - C28 engines, are required to identify the affected turbine wheels by their serial numbers and part numbers, and to remove them from service in accordance with the specified timelines. These entities must ensure that the removal is carried out by qualified personnel following the instructions provided in the AD. They are also required to maintain records of the removal and any related actions taken to comply with the directive. Furthermore, operators must ensure that the engines are not operated once the specified turbine wheels have been removed, unless the removal has been properly documented and any necessary repairs or replacements have been made.
Failure to comply with the AD may result in significant civil or criminal consequences. Non-compliance with airworthiness directives is generally considered a breach of the Civil Aviation Safety Regulations 1998 (CAR 1998). The maximum penalties for such breaches can include substantial fines and, in more severe cases, imprisonment. For corporations, the penalties can be even more severe, with fines potentially reaching up to hundreds of thousands of dollars. Additionally, non-compliance can result in the grounding of aircraft, leading to operational disruptions and potential safety risks. It is therefore imperative for entities governed by this AD to adhere strictly to the requirements and timelines specified within the directive.