AD/CESSNA 180/25 Amdt 1 - Pneumatic Stall Warning System

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Parliament, aim to ensure the safety and regulation of civil aviation within Australia. Specifically, Part 39 - 105 of these regulations includes airworthiness directives that address safety issues in certain aircraft models. The legislative instrument F2006B05040 pertains to the Cessna 180, 182, and Wren 460 series aeroplanes, with Amendment 1 focusing on the pneumatic stall warning system. This directive was introduced to address the problem of inadequate stall warning systems in certain models, ensuring that pilots receive clear stall warnings before potential flight hazards. The policy objective behind these regulations is to enhance flight safety by mandating specific checks and modifications to the stall warning systems in these aircraft.

Scope and Application

The Civil Aviation Regulations 1998, as amended, under the jurisdiction of the Commonwealth of Australia, specifically address the airworthiness directives for the Cessna 180, 182, and Wren 460 Series aeroplanes. The particular directive AD/CESSNA 180/25 Amendment 1 focuses on the pneumatic stall warning system. This applies to all models equipped with the specified pneumatic stall warning systems that do not incorporate the horn reed assembly P/N 0413483-2, P/N 0713348-1 or subsequent, and protective screens over the horn bell and stall warning system opening on the left wing. The directive mandates that the pneumatic stall warning system must be checked for correct operation by applying a slight suction at the stall warning opening, ensuring that the horn produces a clearly audible sound. This check can be performed by the pilot, as referenced in the Cessna 100 Series Service Manual from 1963 to 1967. Additionally, a placard must be installed in full view of the pilot stating "PRE-FLIGHT TEST THE PNEUMATIC STALL WARNING SYSTEM". Compliance with these requirements must occur before each flight for the operational check and within 25 hours of time in service after 5 September 1968 for the placard installation. The directive can be fulfilled by incorporating specified modifications, including replacing the stall warning reed assembly and installing a mesh screen, followed by a flight test to ensure the stall warning horn sounds at 5 to 10 knots above the stalling speed.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105 under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, outlines a directive concerning the Cessna 180, 182, and Wren 460 series aeroplanes, identified as AD/CESSNA 180/25 Amendment 1, focusing on the pneumatic stall warning system (Section 1). The directive applies to all models equipped with a pneumatic stall warning system that do not have the horn reed assembly parts numbers 0413483-2, P/N 0713348-1, or subsequent, and that have protective screens over the horn bell and the stall warning system opening on the left wing (Section 1). The main requirement of this directive is to check the functionality of the pneumatic stall warning system by applying slight suction with the mouth at the stall warning opening in the left wing to ensure the horn provides a clearly audible sound (Section 1). It is suggested to first cover the opening with a clean piece of cloth for this test, as referenced in the Cessna 100 Series Service Manual from 1963 to 1967, Section 16 (Section 1). Additionally, a placard must be installed in full view of the pilot, stating “PRE-FLIGHT TEST THE PNEUMATIC STALL WARNING SYSTEM” (Section 1). Compliance with these requirements must be checked before each flight for the operational check, and the placard must be installed within 25 hours time in service after 5 September 1968 (Section 1). Failure to adhere to these obligations can lead to operational risks, as the pneumatic stall warning system is crucial for alerting the pilot of impending stall conditions. The directive also allows for the removal of these requirements if specific modifications are made, such as replacing the stall warning reed assembly with the specified parts and installing the required mesh screen, followed by a flight test to ensure the stall warning horn sounds at 5 to 10 knots above the stalling speed (Section 1). The regulations stipulate that non-compliance with the airworthiness directives can lead to severe consequences. Although specific penalties are not detailed in the text, breaches of airworthiness directives typically result in serious regulatory actions, including the potential for grounding of the aircraft, enforcement actions, and possibly significant financial penalties. Such non-compliance can also have civil and criminal ramifications, including prosecution for violations of civil aviation safety regulations.