COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Hiller UH-12 Series Helicopters
AD/HILLER 12/40
Amdt 2
Main Rotor Assembly Drag Strut and T-T Bar Pin
1/98
Applicability: Models UH-12A, UH-12B, UH-12C, UH-12D, and UH-12E, and all models converted by STCs 177WE and 178WE.
Requirement: 1. Inspect the alignment of the outboard T-T bar pin, part number 51452, and adjust the alignment, if necessary, in accordance with Hiller Aviation Service Letter 51-2, dated March 31, 1978.
2. Inspect the head of the outboard T-T bar pin for cracks using a dye penetrant or magnetic particle inspection method.
3. Install shims between the inboard end of the drag strut and the outboard T-T bar pin in accordance with the Accomplishment Instructions of Hiller Aviation Service Bulletin 51-9, dated April 8, 1983.
Note: FAA AD 97-20-15 Amdt 39-10151 refers.
Compliance: 1. Unless the initial inspection is already accomplished, within 25 hours’ time in service after 1 January 1998, or at the next 100 hour inspection, whichever occurs first; thereafter at intervals not to exceed 100 hours’ time in service.
2. Unless the initial inspection is already accomplished, within 25 hours’ time in service after 1 January 1998, or at the next 100 hour inspection, whichever occurs first; thereafter at intervals not to exceed 100 hours’ time in service.
3. Unless already accomplished, within 25 hours’ time in service after 1 January 1998, or at the next 100 hour inspection, whichever occurs first.
The compliance of the previous issue of this Directive is unchanged for the repetitive inspection requirement and the one-time requirement.
This amendment becomes effective on 1 January 1998.
Background: Overseas reports were received of T-T bar pin failure due to fretting corrosion, which caused unacceptable vibration and emergency landings.
Amendment 1 included a repetitive inspection for cracks in the head of the outboard T-T bar pin as well as the shimming required by the initial issue of this Directive.
This amendment was prompted by two accidents overseas that were determined to have been caused by failure of the pin.
Amendment 2 is issued in response to a new FAA AD which allows a magnetic particle inspection of the T-T bar pin as an alternative to the currently required dye penetrant inspection.
Overview
The Civil Aviation Regulations 1998, specifically Part 39 - 105, address the safety concerns associated with the Hiller UH-12 Series Helicopters by issuing Airworthiness Directives. The Act was enacted by the Australian Parliament to ensure the safety of civil aviation in Australia. This legislation was introduced to address specific safety issues related to the main rotor assembly of the Hiller UH-12 Series Helicopters, particularly the drag strut and T-T bar pin, which had been implicated in overseas incidents of fretting corrosion and subsequent failures. The policy objective of these regulations is to mandate regular inspections and adjustments to these components to prevent similar incidents from occurring in Australian airspace. Compliance with these directives is critical to maintaining the airworthiness of these aircraft and ensuring the safety of passengers and crew.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, concerns airworthiness directives issued by the Civil Aviation Safety Authority (CASA). The focus here is on the AD/HILLER 12/40 Amendment 2, which pertains to the main rotor assembly drag strut and T-T bar pin of the Hiller UH-12 Series Helicopters, including models UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, and those converted by STCs 177WE and 178WE. This regulation applies to all operators of these helicopters within the Australian jurisdiction. The amendment mandates a thorough inspection and adjustment of the outboard T-T bar pin alignment, a crack inspection of the pin head, and the installation of shims between the drag strut and the T-T bar pin, as per specific instructions. Compliance is required within 25 hours after 1 January 1998 or at the next 100-hour inspection, whichever is sooner, and subsequently at intervals not exceeding 100 hours. The regulation's intent is to mitigate the risks of T-T bar pin failures due to fretting corrosion, which has caused significant vibration and emergency landings in overseas incidents. This directive is in line with the Federal Aviation Administration's AD 97-20-15 Amendment 39-10151, reflecting a collaborative effort to enhance aviation safety standards.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, address the airworthiness directives for the Hiller UH-12 Series Helicopters. Amendment 2 to the AD/HILLER 12/40, which pertains to the main rotor assembly drag strut and T-T bar pin, outlines several key requirements. Firstly, the regulation requires an inspection of the alignment of the outboard T-T bar pin (section 1) and, if necessary, an adjustment according to Hiller Aviation Service Letter 51-2 (section 1). Secondly, the regulation mandates an inspection of the head of the outboard T-T bar pin for cracks using either a dye penetrant or magnetic particle inspection method (section 2). Thirdly, it requires the installation of shims between the inboard end of the drag strut and the outboard T-T bar pin in accordance with Hiller Aviation Service Bulletin 51-9 (section 3). The amendment notes that FAA AD 97-20-15 Amdt 39-10151 also refers to these requirements.
The Civil Aviation Regulations impose specific obligations on the operators and maintainers of the Hiller UH-12 Series Helicopters. Operators must ensure that the specified inspections and adjustments are carried out within the prescribed timeframes. For example, the initial inspection must be completed within 25 hours of service after 1 January 1998 or at the next 100-hour inspection, whichever occurs first. Subsequent inspections must occur at intervals not exceeding 100 hours of service. These requirements are crucial to maintaining the airworthiness of the aircraft and ensuring the safety of all passengers and crew.
Failure to comply with the provisions of the Civil Aviation Regulations can lead to significant consequences. Although the specific penalties are not detailed in the text provided, regulatory non-compliance generally results in civil penalties or enforcement actions under Australian aviation law. These may include fines, operational restrictions, or even the grounding of the aircraft until compliance is achieved. Additionally, repeated or severe non-compliance could potentially lead to criminal charges, depending on the severity of the breach and its impact on aviation safety.
In summary, the Civil Aviation Regulations 1998, Part 39 - 105, mandate specific inspections and adjustments to the main rotor assembly drag strut and T-T bar pin of Hiller UH-12 Series Helicopters. Operators are required to adhere to these provisions to ensure the continued airworthiness of their aircraft. Failure to comply can result in substantial penalties and enforcement actions, underscoring the importance of adherence to these safety directives.