AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/PR/34 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.
Propellers - Variable Pitch - Dowty Rotol
AD/PR/34
Amdt 1
Hub Through Bolts 11/2003
Applicability: All Dowty Rotol propeller models R354/4-123-F/13, R354/4-123-F/20, R375/4-123- F/21, R389/4-123-F/25, R389/4-123-F/26, and R390/4-123-F/27 installed on SAAB 340A and 340B aircraft excluding those propellers assembled using PR1422-B2 sealant in accordance with Dowty Aerospace Service Bulletin (SB) SF340-61-97.
Requirement: 1. Unless previously accomplished in accordance with Dowty Aerospace Propellers SB SF340-61-96 Revision 1, dated 18 April 2000, inspect the propeller hub through bolts for loss of torque in accordance with Dowty Aerospace Propellers SB SF340-61-96 Revision 2, Accomplishment Instructions, Paragraph 3A(2) though 3A(9).
2. Unless previously accomplished in accordance with Dowty Aerospace Propellers SB SF340-61-96 Revision 1, advise the propeller manufacturer of the results of each inspection and record the results of each inspection in the respective propeller records in accordance with SB SF340-61-96 Revision 2, Accomplishment Instructions, Paragraphs 3B and 3C respectively.
Note: The UK CAA has declared the referenced service bulletin MANDATORY.
Compliance: For Requirement 1: Inspect affected propellers between 500 flying hours and 1800 flying hours from 31 August 2000.
Propellers inspected per the original issue of SB SF340-61-96 must be re-inspected if that inspection was accomplished at a period less than 500 flying hours since the hub was last assembled.
For Requirement 2: Upon compliance with Requirement 1. This Amendment becomes effective on 30 October 2003.
Background: This Amendment changes the applicability of the propeller to exclude those propellers which have been assembled using PR 1422-B2 sealant that should prevent the hub through torque from reducing. It also clarifies the specific requirements to be complied with within the reference document.
Propellers - Variable Pitch - Dowty Rotol
AD/PR/34 Amdt 1 (continued)
This Directive was prompted by reports of cracks in the blade retention area of the hub and extensive fretting damage to the hub mating surfaces. These defects have been attributed to loss of hub through bolt torque. Dowty believes through bolt torque loss is associated with the sealant applied to the hub parting surfaces during assembly.
This Directive ensures hub through bolt torque is maintained, thereby reducing the potential for cracking and excessive fretting, and provides data for continuing investigation into this problem.
The original issue of this Airworthiness Directive became effective on 31 August 2000.
Jim Coyne
Delegate of the Civil Aviation Safety Authority 19 September 2003
The above AD is notified in the Commonwealth of Australia Gazette on 8 October 2003.
Overview
The Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Safety Regulations 1998 (CASR) addresses specific safety concerns related to Dowty Rotol propellers installed on SAAB 340A and 340B aircraft. This AD, F2006B06332, was enacted to correct an unsafe condition identified in certain Dowty Rotol propeller models, particularly the risk of cracking in the blade retention area of the hub and extensive fretting damage to the hub mating surfaces due to loss of hub through bolt torque. The policy objective of this directive is to ensure the maintenance of hub through bolt torque to mitigate these risks, thereby enhancing the safety of the aircraft. The directive requires inspection and recording of the torque of specific propeller hub through bolts, and communication of inspection results to the propeller manufacturer, with specific timelines for compliance based on the flying hours since the hub was last assembled.
Scope and Application
The Airworthiness Directive (AD) issued under the Civil Aviation Act 1988 (Cth) applies specifically to certain Dowty Rotol propeller models installed on SAAB 340A and 340B aircraft, with exclusions for those assembled using PR1422-B2 sealant. This AD mandates that the specified propellers must be inspected for loss of torque and the results must be communicated to the propeller manufacturer and recorded, aiming to maintain the structural integrity of the propellers and mitigate the risk of cracking and fretting damage. The directive is issued by a delegate of the Civil Aviation Safety Authority (CASA) and applies nationally within Australia, as per the AD's publication in the Commonwealth of Australia Gazette. The AD extends to all relevant aircraft and propellers within the specified parameters, ensuring compliance through the prescribed inspection and recording processes.
Key Provisions
The Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 (CASR) mandates specific actions to be taken concerning Dowty Rotol propellers on SAAB 340A and 340B aircraft. The directive applies to all Dowty Rotol propeller models specified in the applicability section, excluding those assembled with PR1422-B2 sealant. The main requirement (Section 1) is to inspect the propeller hub through bolts for loss of torque, following specific instructions from Dowty Aerospace Propellers Service Bulletin (SB) SF340-61-96 Revision 2. The second requirement (Section 2) mandates advising the propeller manufacturer of inspection results and recording these results in the respective propeller records, also in accordance with SB SF340-61-96 Revision 2.
Operators and owners of the specified aircraft must ensure that these inspections and record-keeping are carried out as per the outlined requirements. For Requirement 1, inspections must be completed between 500 and 1800 flying hours from 31 August 2000. If the original inspection was done less than 500 flying hours since the hub was last assembled, a re-inspection is necessary. Requirement 2 must be completed upon compliance with Requirement 1. This directive was made effective on 30 October 2003.
Failure to comply with the AD may result in severe consequences, including aircraft being deemed unairworthy. Non-compliance can lead to enforcement actions by the Civil Aviation Safety Authority (CASA), which may include fines, penalties, and potential legal action. The exact penalties would depend on the nature and severity of the non-compliance but could involve significant financial penalties or operational restrictions. It is crucial for operators and owners to adhere strictly to the AD to ensure the continued airworthiness and safety of the aircraft.