AD/TB10/16 - Lower Engine Cowl Carburettor Air Supply

Overview

The Civil Aviation Regulations 1998, under Part 39 - 105, addresses the safety requirements for specific aircraft, including the Aerospatiale (Socata) TB9 and TB10 (Tobago) series aeroplanes. This regulation was enacted to ensure the safe operation of these aircraft by mandating compliance with specific airworthiness directives, such as AD/TB10/16, which focus on preventing potential hazards related to engine cowlings. The Civil Aviation Safety Authority, established under the Civil Aviation Act 1988, is responsible for enacting and enforcing these regulations to safeguard the public and maintain high safety standards in civil aviation. The policy objective of this legislation is to mitigate risks associated with aircraft malfunctions, ensuring that all aircraft meet stringent safety criteria to prevent incidents that could compromise flight safety. The regulation specifically addresses a known issue with the lower engine cowl NACA fitting on the TB9 and TB10 series aircraft, which can be damaged if the supply hose clamp is overtightened. Such damage can lead to the intake hose coming loose, potentially restricting engine operation. This directive aligns with the French civil aviation authority's technical requirements, DGAC AD 90-240 (A), with an effective date revised to 31 March 1991. The aim is to ensure all affected aircraft are compliant with these safety standards, thereby preventing potential in-flight hazards.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, under the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, addresses the airworthiness of Aerospatiale (Socata) TB9 and TB10 (Tobago) series aeroplanes. This legislation applies to all TB9 and TB10 series aircraft with serial numbers from 1 to 944 inclusive, provided they are equipped with a lower cowling carburettor air supply. The regulation mandates compliance with the technical requirements outlined in DGAC AD 90-240 (A) with a revised effective date of 31 March 1991. The primary concern addressed is the potential damage to the lower engine cowl 'NACA' fitting due to overtightening of the supply hose clamp, which could lead to the intake hose coming loose and subsequently restrict engine operation. The scope of this legislation encompasses aircraft owners, operators, and maintenance personnel who must ensure adherence to these specific airworthiness directives to maintain the safety and airworthiness of the affected aircraft.

Key Provisions

The key provisions of the Civil Aviation Regulations 1998, particularly those pertaining to the Aerospatiale (Socata) TB9 and TB10 (Tobago) series aeroplanes, are detailed in Part 39 - 105, specifically AD/TB10/16. This regulation addresses the lower engine cowl carburettor air supply for aircraft in the specified series and serial numbers. The regulation requires compliance with the technical requirements outlined in DGAC AD 90-240 (A), with an effective date revised to 31 March 1991. Essentially, this means that all TB9 and TB10 series aircraft from serial numbers 1 to 944, inclusive, fitted with a lower cowling carburettor air supply, must adhere to the specified requirements to ensure the safety and operational integrity of the aircraft. The obligations imposed by this regulation are clear and focused on maintaining the structural integrity of the lower engine cowl. Aircraft owners, operators, and maintenance personnel must ensure that the carburettor air supply hose clamp is not overtightened, as this can cause damage to the lower engine cowl `NACA’ fitting. If this fitting is compromised, it could lead to the intake hose coming loose, which in turn might restrict engine operation. Consequently, maintaining the correct tightness of the hose clamp is critical to prevent such failures. Failure to comply with the requirements set forth in AD/TB10/16 could lead to serious operational risks. While the Civil Aviation Regulations 1998 do not specify particular offences or penalties directly within this directive, non-compliance with airworthiness directives can generally result in severe consequences. These can include grounding of the aircraft, which prevents it from flying until the issues are rectified, and potential enforcement actions by the Civil Aviation Safety Authority (CASA). In extreme cases, continued non-compliance could lead to more stringent regulatory actions, including fines and other civil or criminal penalties as stipulated in the broader legislative framework governing aviation safety in Australia. In summary, AD/TB10/16 mandates specific actions to prevent damage to the lower engine cowl carburettor air supply in Aerospatiale (Socata) TB9 and TB10 series aeroplanes. Compliance involves adhering to the technical specifications provided in DGAC AD 90-240 (A) and ensuring that the hose clamp is not overtightened. Non-compliance with these directives could result in significant operational risks and potential regulatory enforcement actions by CASA.