COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Pilatus Porter PC-6 Series Aeroplanes
AD/PC-6/44 Horizontal Stabiliser Trim Actuator 12/99 TX
Applicability: All PC-6 aircraft fitted with horizontal stabiliser trim actuator Pilatus P/N 978.73.18.101 or 978.73.18.102 or 978.73.18.103.
Requirement: Inspect in accordance with the requirements of Pilatus Service Bulletin PC-6 No 178 dated 29 Sept 1999.
Note: Swiss FOCA AD HB 99-507 refers.
Compliance: For aircraft with more than 2000 landings or more than 500 hours TIS if the number of landings has not been recorded, inspect before further flight.
For all other aircraft, inspect at the next 100 hourly inspection.
This Airworthiness Directive becomes effective on 11 October 1999.
Background: The Swiss Airworthiness Directive was written after the FOCA received a report of a lower lug of the electrical horizontal stabiliser trim actuator was found cracked and with a lug segment missing. The cause is suspected to be loosening of the staked bearing causing excessive wear and hence failure of the lower lug.
Overview
The Civil Aviation Regulations 1998, specifically PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES, was enacted to ensure the safety of civil aviation in Australia by establishing standards and regulations for airworthiness directives. This legislation is aimed at addressing potential safety issues and ensuring that all civil aircraft meet required safety standards. The Civil Aviation Safety Authority (CASA), operating under the authority of the Civil Aviation Act 1988, implements these regulations to safeguard the public and maintain the integrity of the aviation industry. AD/PC-6/44, which pertains to the Pilatus Porter PC-6 Series Aeroplanes and their horizontal stabiliser trim actuator, was introduced to address a specific safety issue identified in certain models of these aircraft, ensuring that all affected aircraft are inspected and maintained to prevent potential failures and ensure continued airworthiness.
The Airworthiness Directive AD/PC-6/44 was issued following a report from the Swiss Federal Office of Civil Aviation (FOCA) about a cracked lower lug of the horizontal stabiliser trim actuator, leading to a suspected loosening of the staked bearing and subsequent failure. The directive mandates specific inspection protocols for all PC-6 aircraft equipped with certain horizontal stabiliser trim actuators, ensuring that these aircraft are maintained to the highest safety standards. The directive became effective on 11 October 1999, with requirements varying based on the number of landings and total flight hours to ensure timely and effective inspections. This directive is a critical measure in maintaining the safety and reliability of the Pilatus Porter PC-6 Series Aeroplanes in Australian airspace.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates the application of Airworthiness Directives (AD) to ensure the safety and airworthiness of aircraft within Australia. This particular AD, AD/PC-6/44, applies to all Pilatus Porter PC-6 series aeroplanes equipped with a horizontal stabiliser trim actuator identified by Pilatus part numbers 978.73.18.101, 978.73.18.102, or 978.73.18.103. The directive requires inspections to be conducted in accordance with Pilatus Service Bulletin PC-6 No 178 dated 29 September 1999, referencing the Swiss FOCA AD HB 99-507. For aircraft with more than 2000 landings or more than 500 hours of total time in service if landing records are unavailable, the inspection must be performed before further flight. For all other aircraft, the inspection must occur at the next 100-hourly inspection. This directive took effect on 11 October 1999, following a Swiss Federal Office of Civil Aviation report of a cracked and partially missing lower lug on the electrical horizontal stabiliser trim actuator, attributed to the loosening of the staked bearing leading to excessive wear and eventual failure.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105 concerning the Civil Aviation Safety Authority's schedule of airworthiness directives, mandates particular safety measures for Pilatus Porter PC-6 Series Aeroplanes. This particular directive, AD/PC-6/44, focuses on the horizontal stabiliser trim actuator, particularly those identified by Pilatus Parts Numbers 978.73.18.101, 978.73.18.102, and 978.73.18.103. Section (1) of this directive outlines the necessity for an inspection in compliance with Pilatus Service Bulletin PC-6 No 178 dated 29 September 1999. The directive references Swiss FOCA AD HB 99-507 for additional context.
The obligations imposed by this directive vary based on the aircraft's operational history. For aircraft with over 2000 landings or more than 500 hours of Total Cumulative Time in Service (TIS) if the landing count is not recorded, the directive requires an inspection before further flight. For all other aircraft, the inspection must be conducted at the next 100-hourly inspection. Compliance with these inspection requirements is crucial to ensure the integrity and safety of the horizontal stabiliser trim actuator. The directive became effective on 11 October 1999, establishing a clear timeline for adherence.
Failure to comply with the requirements of this airworthiness directive may result in significant consequences. The primary concern stems from the potential for the lower lug of the electrical horizontal stabiliser trim actuator to crack and lose a segment, leading to excessive wear and eventual failure. This condition could compromise the aircraft's stability and control, posing serious risks during flight. Although specific penalties or enforcement details are not explicitly mentioned in the directive, non-compliance could result in civil or criminal penalties under broader aviation safety laws. These could include fines, suspension of airworthiness certificates, or other regulatory actions as deemed appropriate by the Civil Aviation Safety Authority.