Overview

The Civil Aviation Regulations 1998, specifically under Part 39 – 105, were enacted by the Commonwealth of Australia to ensure the safety of civil aviation within its jurisdiction. One of the key issues these regulations aim to address is the potential for hazards in flight resulting from technical malfunctions in aircraft systems. The Civil Aviation Safety Authority, through the issuance of Airworthiness Directives (ADs), provides specific instructions for the maintenance and modification of aircraft to mitigate these risks. The AD/LEARJET/25 concerning Gates Learjet 24 & 25 Series Aeroplanes is an example of such measures, targeting the deactivation and modification of the Automatic Flight Control System to prevent hazardous flight attitudes due to pitch axis malfunctions. The overarching policy objective of these regulations is to maintain the highest standards of air safety by ensuring all aircraft conform to stringent safety protocols and are regularly inspected and maintained as required.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives for Gates Learjet 24 & 25 Series Aeroplanes, with the directive AD/LEARJET/25 focusing on the Automatic Flight Control System. This legislation applies to all models 24 with serial numbers 24-100 and subsequent, all models 25 with serial numbers 25-003 and subsequent, all models 28 with serial numbers 28-001 and subsequent, and all models 29 with serial numbers 29-001 and subsequent. The directive mandates deactivation of the pitch function of the Automatic Flight Control System by pulling the AFCS Pitch DC Circuit Breaker to the off position and banding it to prevent use of this function. A placard must also be installed to indicate that the autopilot pitch axis is inoperative, and the aircraft must be operated in accordance with this placard. The compliance requirements necessitate deactivation and placard installation before further flight, with modifications to the elevator control system and autopilot pitch trim monitor test switch installation before 1 May 1981. The geographic reach of this directive is national, applying to all civil aircraft operating within Australia, governed by the Civil Aviation Regulations 1998. The legislation does not provide for any exclusions or exemptions, and compliance is mandatory for the specified aircraft models.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, outlines several key provisions regarding airworthiness directives for Gates Learjet 24 & 25 Series Aeroplanes, with AD/LEARJET/25 focusing on the Automatic Flight Control System (AFCS). Section 4/81 mandates the deactivation of the pitch function of the FC-110 AFCS or AFC/SS by pulling the AFCS Pitch DC Circuit Breaker to the off position and securing it to prevent its use. This must be confirmed as the only deactivated circuit or control. The specific location for this action varies depending on the serial number of the aircraft model (paragraph 1). Additionally, a placard indicating that the autopilot pitch axis is inoperative must be installed in a visible location, and the aircraft must be operated in accordance with the Airspeed limitations outlined in the appropriate Aircraft Flight Manual (paragraph 2). Furthermore, the elevator control system must be inspected to confirm the presence of Pitch Axis Servo (DC Torquer), P/N 6600163-( ), and, if present, the aircraft must be modified by incorporating the autopilot pitch trim monitor test switch according to Gates Learjet Airplane Modification Kit AMK 80-16B, Change 2 (paragraph 3(a)). If the Pitch Axis Servo is not installed, it must be replaced, and the aircraft must be modified by incorporating the autopilot pitch trim monitor test switch according to Gates Learjet Airplane Modification Kits AMK 80-3, Change 4, and AMK 80-16B, Change 2, respectively (paragraph 3(b)). The obligations under these regulations are stringent and require adherence to specific timelines and modifications to ensure the safety and airworthiness of the aircraft. Operators must deactivate the AFCS pitch function before further flight and ensure the placard is installed and visible to the crew. Moreover, operators must conduct a visual inspection of the elevator control system and perform the necessary modifications by the specified date of 1 May 1981. Failure to comply with these requirements could result in non-compliance with the Civil Aviation Regulations 1998, potentially leading to serious safety hazards and operational restrictions. Failure to comply with the provisions of this airworthiness directive could result in serious consequences. Non-compliance with these requirements can lead to the aircraft being deemed unairworthy, which could result in grounding of the aircraft and potential fines or penalties imposed by the Civil Aviation Safety Authority (CASA). In severe cases, continued operation of a non-compliant aircraft could lead to criminal charges, with potential maximum penalties including substantial fines and imprisonment. It is crucial for operators to adhere strictly to these regulations to ensure the safety of flight operations and to avoid any legal repercussions.