COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Agusta A109 Series Helicopters
AD/A109/16
Amdt 3
Main Rotor Blades 12/90 DM
Applicability: All models fitted with main rotor blades P/N 109-0103-01-( ) (all dash numbers), serial numbers 378 through to 1519 inclusive, which have achieved 300 or more hours component time in service.
Requirement: Action in accordance with Agusta Bollettino Tecnico No 109-79, dated 27 July 1990. The radiographic inspection should be performed using X-rays of energy no greater than 50 KVp to obtain the required contrast sensitivity, in the area of interest, of no greater than 1%.
Note 1: This Bollettino Tecnico supersedes B T No 109-6, Revs A and B. Eddy current inspections performed in accordance with previous issues of this AD (B T No 109-6) shall be accepted as meeting the eddy current inspection requirement of this amendment.
Note 2: Approval to perform the radiographic inspection in accordance with Part 2 of the Requirement document and Agusta Report No 109-02-79, issued 15 July 1990, may be granted upon application to the Authority. Applicants will need access to suitable radiographic equipment and must be able to demonstrate 1% or better contrast sensitivity on a representative specimen.
Compliance: For Part 1 of the Requirement document: At intervals not to exceed 25 hours time in service and before further flight upon the occurrence of anomalous vibratory conditions, until such time as Part 2 of the Requirement Document has been accomplished.
For Part 2 of the Requirement document: At operator’s option.
Background: Several cases of main rotor blade cracking have been found in service, including one which failed catastrophically. Fatigue cracking has been initiated by chordwise scoring, introduced during manufacture, adjacent to spar mass balance weights.
Amendment 2 reduced the initial inspection threshold to 600 hours.
Amendment 3 further reduces the initial inspection threshold to 300 hours, in accordance with the manufacturer’s recommendations, and also introduces a once only inspection procedure to positively identify blades which have unacceptable levels of scoring. Such blades must be removed from service before further flight. Any positive indications, whether confirmed or otherwise, resulting from these inspections, should be the subject of a Major Defect Report.
Overview
The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes Airworthiness Directives that are essential in maintaining the safety standards of aircraft operating in Australia. The regulations were enacted by the Parliament of the Commonwealth of Australia to ensure that all civil aviation activities within the country adhere to stringent safety measures. One such Airworthiness Directive, AD/A109/16 Amendment 3, addresses the issue of main rotor blade cracking in Agusta A109 Series Helicopters. This amendment was introduced to mitigate the risk of catastrophic failure due to fatigue cracking, which has been traced back to manufacturing defects such as chordwise scoring adjacent to spar mass balance weights. The policy objective of this directive is to enhance the safety of air operations by mandating regular inspections and maintenance actions to prevent such failures.
The Civil Aviation Safety Authority oversees the implementation of these directives, ensuring that helicopter operators comply with the specified requirements to maintain airworthiness. The directive requires that helicopters with specific main rotor blade serial numbers and those that have accumulated a certain number of flight hours undergo radiographic inspections to detect any unacceptable levels of scoring. This measure is designed to ensure that any blades identified with significant scoring are removed from service, thereby preventing potential catastrophic incidents. By reducing the inspection threshold to 300 hours, the directive aims to address the problem more proactively, aligning with the manufacturer's recommendations to improve safety standards.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Agusta A109 Series Helicopters equipped with main rotor blades P/N 109-0103-01-( ) (all dash numbers), within the serial number range of 378 to 1519 inclusive, that have accumulated 300 or more hours of component time in service. This regulation is a crucial part of ensuring the airworthiness of these helicopters, focusing on the maintenance and inspection of the main rotor blades to prevent potential catastrophic failures. The geographic and jurisdictional reach of this regulation is national, as it falls under the Civil Aviation Safety Authority, which oversees all aspects of civil aviation within Australia. There are no exclusions or exemptions specified within this particular Airworthiness Directive, meaning that all applicable helicopters must adhere to the outlined requirements. The application of the regulation can be further defined through subordinate instruments, which may provide additional specifications or clarifications on the implementation and compliance processes.
Key Provisions
The Civil Aviation Regulations 1998, under Part 39 - 105, specifically address the airworthiness of Agusta A109 Series Helicopters, with a focus on Main Rotor Blades in AD/A109/16 Amendment 3. This directive applies to all models fitted with main rotor blades of a particular part number and serial number range, provided they have accumulated 300 or more hours of component time in service (Section 12/90 DM). The primary requirement is for a radiographic inspection conducted according to Agusta Bollettino Tecnico No 109-79, dated 27 July 1990. The inspection must utilise X-rays with an energy level of no more than 50 KVp to ensure the required contrast sensitivity of no greater than 1% in the area of interest. Eddy current inspections performed according to previous versions of this directive (B T No 109-6) are still acceptable if conducted in compliance with the previous requirements.
The obligations under this directive are quite specific and demand rigorous adherence. Operators must ensure that the radiographic inspection is carried out at intervals not exceeding 25 hours of time in service and before further flight if anomalous vibratory conditions are detected, until the more comprehensive inspection outlined in Part 2 of the Requirement Document is completed. For Part 2, the inspection can be conducted at the operator's discretion. The directive also allows for the approval of radiographic inspections to be granted by the Authority, provided the applicant has access to suitable radiographic equipment and can demonstrate the required contrast sensitivity on a representative specimen.
Non-compliance with these directives can lead to severe consequences. The primary risk is the potential for main rotor blade cracking, which has already resulted in incidents, including one catastrophic failure. Such failures can be attributed to fatigue cracking initiated by chordwise scoring during manufacturing, adjacent to spar mass balance weights. Any blades found to have unacceptable levels of scoring must be removed from service before further flight. Positive indications from these inspections must be reported as Major Defect Reports. The legislative framework does not explicitly state penalties for non-compliance, but the potential for catastrophic outcomes underscores the critical nature of adhering to these safety directives.