AD/INST/29 - Bendix M-4 (A,B,C,D) Automatic Flight Control System Servo - Inspection and Modification

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, address the need for ensuring the safety of aircraft through various regulatory measures, including airworthiness directives. One such directive is the AD/INST/29 which specifically targets the Bendix M-4 (A,B,C,D) Automatic Flight Control System Servo. This legislative instrument was introduced to address the problem of mechanical seizure in primary servo motors, which can lead to increased actuation forces and potentially compromise flight safety. The policy objective is to ensure the continued airworthiness of affected aircraft by requiring inspections and modifications to the specified servo components. The Civil Aviation Safety Authority, under the regulations, mandates compliance with these directives to maintain the safety standards within the civil aviation sector. The AD/INST/29 directive applies to all models of the specified servos delivered, repaired, or overhauled after January 1, 1979, and mandates compliance within 100 hours of service after January 31, 1981. This directive aims to prevent mechanical failures that could endanger the primary flight controls, ensuring that the aircraft remain safe for operation. By enforcing this directive, the Civil Aviation Safety Authority seeks to mitigate risks associated with servo motor seizures, thereby safeguarding the integrity of flight operations and the safety of passengers and crew.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107 under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, mandates the inspection and modification of the Bendix M-4 (A,B,C,D) Automatic Flight Control System Servo for certain aircraft models. This regulation applies to all Models 3013E, 3013F, 3013G, 3013H, 3013J, and 3013K primary servos delivered, repaired, or overhauled after 1 January 1979 that do not contain Modification Number 4. It also covers any primary servos that have had magnetic clutches installed after this date. The directive is designed to address instances of mechanical seizure reported overseas, which could compromise primary flight controls and increase the actuation forces required by the pilot. Compliance with these airworthiness directives is mandatory within 100 hours of time in service after 31 January 1981, as specified in the Bendix Alert SB M-4D-060 document.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39, Section 107, includes detailed directives for maintaining the airworthiness of certain aircraft components, with a focus on automatic flight control systems. Specifically, Airworthiness Directive AD/INST/29 pertains to the Bendix M-4 Automatic Flight Control System Servo, requiring inspections and modifications to ensure safety. This directive applies to all models 3013E, 3013F, 3013G, 3013H, 3013J, and 3013K primary servos (1U014-01, 1U014-02, 1U014-03) delivered, repaired, or overhauled after 1 January 1979, unless they already have Modification Number 4. Additionally, any primary servos that have had magnetic clutches installed or repaired/overhauled after this date are also subject to the directive. Compliance with this directive must be achieved within 100 hours of time in service following 31 January 1979. Entities and parties governed by these regulations are obligated to ensure that the specified primary servos are inspected and modified as required. This involves identifying and addressing any primary servos that do not meet the criteria for exemption, particularly those manufactured by Bendix or those that have been repaired or overhauled after the specified date. The directive is clear that any primary servos which do not have Modification Number 4 must be inspected and modified to prevent potential mechanical seizures that could compromise flight control. Compliance must be verified, and any modifications must be documented according to the guidelines provided in the Bendix Alert SB M-4D-060. Failure to comply with these airworthiness directives can result in significant civil and criminal consequences. The Civil Aviation Safety Authority (CASA) has the authority to enforce these regulations, and non-compliance may lead to penalties. While the specific penalties are not detailed in the provided text, non-compliance with airworthiness directives generally results in enforcement actions, which may include fines, suspension of flight operations, or even criminal charges if the non-compliance leads to a safety incident. It is crucial for operators and maintainers to adhere strictly to these directives to avoid such repercussions.