AD/PMC/27 Amdt 1 - Attachment Studs

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia and administered by the Civil Aviation Safety Authority (CASA), were established to ensure the safety of civil aviation in Australia. The regulations have been amended over the years to address emerging safety concerns and technological advancements. One such amendment is AD/PMC/27, which pertains to the modification of attachment studs in variable pitch propellers, specifically for McCauley model 3AF34C74, 3AF34C86, and 3AF34C92 propellers fitted to certain Cessna and Beagle aircraft. This amendment was introduced to address a safety issue related to the attachment studs of these propellers, ensuring that all applicable hubs are properly modified to comply with the specified standards, thus enhancing the overall airworthiness and safety of the affected aircraft. The policy objective of this amendment is to ensure that the aircraft in question meet the necessary safety standards by requiring the modification of the attachment studs in accordance with McCauley Service Bulletins No 102 and 102-1. This includes ensuring that the modified hubs have eight studs protruding between 44.5mm to 45mm above the hub, eight 12mm thick spacers, and the addition of the letter “P” as a suffix to the part number. This amendment is aimed at preventing potential safety hazards associated with improperly modified propellers, thereby contributing to the safety and reliability of civil aviation in Australia.

Scope and Application

The Civil Aviation Safety Authority (CASA) Regulations 1998, under Part 39 - 107, establish the scope and application of the Airworthiness Directives, specifically addressing the modification of attachment studs for certain McCauley variable pitch propellers. This legislative instrument applies to all model 3AF34C74, 3AF34C86 and 3AF34C92 propellers that are fitted to Cessna 411, 411A, 421, 421A, 421B, or Beagle B-206 series 2 aircraft. The requirement stipulates that the propeller hubs must be modified in accordance with McCauley Service Bulletins No 102 and 102-1. Compliance must be achieved prior to the installation of these propellers unless the modification has already been carried out. The modification involves ensuring that there are eight studs protruding between 44.5mm and 45mm above the hub, using eight 12mm thick spacers, and adding the letter "P" as a suffix to the part number for the modified hubs. The directive is applicable across the Commonwealth of Australia, ensuring a uniform approach to aircraft safety and airworthiness standards.

Key Provisions

The main sections of the Civil Aviation Regulations 1998 (CAR) Part 39 - 107, pertaining to the Airworthiness Directives for McCauley Variable Pitch Propellers, specifically address the modification of attachment studs in certain propeller models. Section 107.111(1) mandates that all model 3AF34C74, 3AF34C86, and 3AF34C92 propellers fitted to Cessna 411, 411A, 421, 421A, 421B, and Beagle B-206 series 2 aircraft must be modified in accordance with McCauley Service Bulletin (SB) No 102 and 102-1. The requirement necessitates compliance unless the modifications have already been carried out prior to installation. The obligations imposed by these regulations are clear and specific. Aircraft owners and operators must ensure that their propellers are modified to meet the specifications outlined in McCauley SB No 102 and 102-1. This includes modifying the hubs so that eight studs protrude 44.5mm to 45mm above the hub, incorporating eight 12mm thick spacers, and adding the letter "P" as a suffix to the part number of the modified hubs. This requirement ensures that the propellers are safe and comply with airworthiness standards. Failure to comply with the Airworthiness Directives can lead to serious consequences. Under section 107.111(2), non-compliance can result in enforcement actions against the aircraft owner or operator. These actions can include fines, aircraft grounding, or other regulatory penalties, which are intended to ensure that all aircraft meet the necessary safety standards. The seriousness of these consequences underscores the importance of adhering to the specified modifications. In summary, the Civil Aviation Regulations 1998 mandate that specific propellers be modified in accordance with McCauley SB No 102 and 102-1 to ensure airworthiness. Aircraft owners and operators are required to comply with these modifications, which include specific measurements and additions to the propeller hubs. Non-compliance can lead to enforcement actions, highlighting the critical nature of adhering to these directives to maintain safety standards.