AD/CESSNA 180/67 - Aileron Balance Weight

Overview

The Civil Aviation Regulations 1998, under Part 39 - 105, includes Airworthiness Directives (AD) designed to ensure the continued safety of aircraft in Australian airspace. Specifically, AD/CESSNA 180/67, enacted in 1984, addresses the problem of potential destructive aileron flutter in Cessna 180, 182, and Wren 460 series aeroplanes. This directive was introduced to mitigate risks associated with improperly installed aileron balance weights, which can lead to severe aerodynamic instability. The Civil Aviation Safety Authority, as the enforcing body, aims to ensure compliance with safety standards to protect both the aircraft and its occupants. The policy objective is to maintain airworthiness by requiring specific inspections and modifications to aircraft that have been modified under certain circumstances prior to a specified date. This legislative instrument mandates that owners or operators of affected Cessna models must determine if their aircraft were modified according to specific criteria before August 1, 1983, and subsequently inspect and, if necessary, replace the aileron balance weights to the correct specifications. Failure to comply with these requirements could result in severe operational risks, including aileron flutter, which endangers flight safety. Compliance with this directive must be achieved within 50 hours of the aircraft being in service after January 31, 1983.

Scope and Application

The Civil Aviation Safety Authority (CASA) Regulations 1998, as specified in Part 39 - 105, provide detailed safety directives for the maintenance and operation of various aircraft types, including the Cessna 180, 182 and Wren 460 Series Aeroplanes. This particular directive, AD/CESSNA 180/67, applies to all models 180 through 180H, 180J and 180K aircraft that have been modified in accordance with the Robertson STC SA 1435WE, as well as models 182 through 182R, R182, T182 and TR182 modified under the Robertson STC SA 1382WE. The directive mandates that if an aircraft was modified at Robertson Aircraft Corporation repair station No. 415-23 prior to 1 August 1983, it must undergo an inspection to determine the correct installation of aileron balance weights. The inspection requires measuring the height of all aileron balance weights, with specific requirements for replacement if any are found to be incorrectly installed. Compliance with these directives is necessary within 50 hours of time in service after 31 January 1983, to prevent destructive aileron flutter. This regulation applies nationally across Australia, overseen by CASA, and there are no stated exclusions or exemptions in this directive, though compliance may be extended or modified through subsequent legislative instruments or CASA directives.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandate Airworthiness Directives for various aircraft models, including the Cessna 180, 182, and Wren 460 series aeroplanes. Section AD/CESSNA 180/67 focuses on the aileron balance weight for these aircraft. The directive applies to all Cessna 180 models from 180 through 180H, 180J, and 180K that have undergone modifications in accordance with Robertson STC SA 1435WE, as well as models 182 through 182R, R182, T182, and TR182 modified under Robertson STC SA 1382WE. To comply with this directive, the first requirement is to ascertain if the aircraft has been modified by Robertson Aircraft Corporation, repair station number 415-23, prior to 1 August 1983. If the aircraft was indeed modified during this period, it is then necessary to measure the height of all aileron balance weights. If the measured height of all weights is approximately 3/4 inch, the weights are correctly installed, and no further action is required. However, if any weight measures approximately 1/2 inch, it must be replaced with a balance weight of the appropriate part number in accordance with the applicable STC data or Robertson SB No. 20. After replacement, the ailerons must be rebalanced within the limits specified by the Cessna Aircraft Company Service Manual for the specific aircraft involved. These requirements must be met within 50 hours of time in service after 31 January 1983. Failure to comply with the directive could lead to destructive aileron flutter, which poses significant safety risks. The obligations imposed on the aircraft owners and operators are clear: ensure that any modifications and inspections are carried out by authorised personnel and within the specified timeframes. Non-compliance with these regulations could result in severe penalties, including fines, aircraft grounding, or other enforcement actions taken by the Civil Aviation Safety Authority. The potential civil and criminal consequences underscore the importance of adhering to these directives to maintain the safety and airworthiness of the aircraft.