COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes
AD/AC/66
Amdt 8
Wing Fatigue Life Limitation 13/89
Applicability: As specified in the Requirement.
Requirement: Retire wing main spar lower cap assembly from service (or modify in accordance with a scheme approved by the Authority) in accordance with the schedule below:
AIRCRAFT MODELS AFFECTED
(The straps referred to are wing spar lower cap fatigue life improvement reinforcements)
SPAR CAP RETIREMENT LIFE
(Hours’ Time in Service)
| MTOW of 6750 lb. | MTOW of 7400 lb. |
500B | 30400 | - |
500B used in low level survey type operations | 19900 | - |
500U with external strap (Pre S/N 1731) | 23200 | 17700 |
500U with external strap (Pre S/N 1731) and used in low level survey type operations | 15900 | 12100 |
560F | 24100 | |
560F used in low level survey type operations | 16300 | |
| MTOW of 8000 lb. | MTOW of 8500 lb. |
680F | 17100 | - |
680FL with external strap (Pre S/N 1731) | 17100 | 11200 |
680FL with internal strap (S/N 1731 and on) | 3900 | 30000 |
680FL (P) with external strap (Pre S/N 1731) | - | 25200 |
680T | | 27100 | |
680V, 680W (Pre S/N 1731) with external strap | | 23500 | |
685 | | 20700 | |
690, 690A | | 12900 | |
690B | | 11500 | |
690C, 695 - canted aerodynamic wing tips | | 11300 | |
690C, 695 - plain tips for total operational life | | 24800 | |
695A | | To be Advised. | |
|
Note 1: If Models 680F(P) or 680FL(P) aircraft are flown predominantly at low or zero cabin differential pressure, then the retirement life of Models 680F or 680FL respectively, shall apply.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Note 2: Should models other than the 500B, 500U and 560F be used in low level survey type operations, the Authority must be advised as a reduction in life will be necessary. For all aircraft engaged in low level operations appropriate log book entries must be made listing times actually engaged in such operations. The Authority must also be advised of any aircraft operating consistently at a flight duration of less than 45 minutes when averaged over the life of the aircraft.
Note 3: The wing spar lower cap assembly subject to retirement consists of the spar cap “T” section element together with the nesting angles, outer wing spar cap splice angles and, as fitted, either internal or external reinforcement straps. The outer wing spar caps need not be retired.
Note 4: On the basis of currently available fatigue substantiating data only one spar cap assembly replacement is permitted without further evaluation. This will normally allow only a single life extension from spar cap replacement or reinforcement/modification.
Note 5: Models not listed in the schedule generally have fatigue lives greater than 30000 hours and are thus unlikely to be affected.
Compliance: As specified in the Requirement.
Background: The retirement lives of this Directive are based directly on data provided by the manufacturer. Amendment 7 was raised to clarify the strap configuration for those models which were fitted with any one of a number of strap configurations during their production life. For all models, the internal straps were fitted to S/N 1731 and subsequent. Amendment 8 corrects some typographical errors.
Overview
The Civil Aviation Regulations 1998, as amended, address various safety directives related to civil aviation, one of which is the Airworthiness Directive (AD) concerning the Twin Commander series aeroplanes (Gulfstream/Rockwell/Aerocommander 500, 600, and 700). This AD, specifically Amendment 8, was introduced to address issues related to the fatigue life limitations of the wing main spar lower cap assemblies in these aircraft models. The Australian Parliament enacted this regulation to ensure the safety and airworthiness of these aircraft. The policy objective of this legislation is to provide clear guidelines for the retirement or modification of specific components to prevent structural failures due to fatigue, thus enhancing aviation safety. This AD is issued by the Civil Aviation Safety Authority (CASA) to mandate the retirement of certain wing components based on their time in service and operational conditions, aiming to maintain the structural integrity of the aircraft over their operational lives.
Scope and Application
The Civil Aviation Safety Authority Schedule of Airworthiness Directives, specifically AD/AC/66 Amendment 8, pertains to the Twin Commander series of aircraft, including models 500, 600, and 700. This legislation applies to aircraft operators, maintenance personnel, and potentially other entities involved in the maintenance and operation of these specific aircraft models. The directive sets forth specific requirements for the retirement of the wing main spar lower cap assembly or its modification, depending on the aircraft's time in service and operational conditions. The geographic reach of this legislation is national, applying to all civil aviation activities within Australia, governed under the Civil Aviation Regulations 1998. The directive includes specific exclusions for models not listed in the schedule, which generally have fatigue lives exceeding 30000 hours and are thus unlikely to be affected by the stipulated requirements. The applicability and compliance of these directives may be further extended or restricted through subordinate instruments as necessary to ensure safety and regulatory adherence.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, address airworthiness directives concerning the Twin Commander (Gulfstream/Rockwell/Aerocommander 500, 600, and 700) series aeroplanes, particularly focusing on wing fatigue life limitations. Section AD/AC/66 Amendment 8 mandates the retirement or modification of the wing main spar lower cap assembly, as detailed in the schedule, to ensure continued airworthiness (sections 13/89). The schedule specifies the retirement life in terms of time in service for various aircraft models and maximum take-off weights (MTOW), with additional considerations for aircraft used in low-level survey operations.
Operators and owners of affected aircraft must comply with these directives, which require adherence to the specified retirement schedules. For aircraft with external strap configurations, specific modifications and retirement timelines are outlined. Operators must ensure that all modifications and retirements are carried out in accordance with the directives and that approved schemes are followed if modifications are chosen over retirement. Furthermore, operators must maintain detailed records of low-level survey operations and notify the Civil Aviation Safety Authority (CASA) of any such operations or flight durations of less than 45 minutes over the aircraft's life.
Failure to comply with these airworthiness directives can lead to serious consequences. The Civil Aviation Regulations 1998 impose penalties for non-compliance, which may include fines or imprisonment. The exact penalties depend on the severity and frequency of the breach, but operators must ensure strict adherence to avoid any legal repercussions. Non-compliance could also result in the grounding of the aircraft, thereby affecting operational capabilities and potentially leading to further regulatory actions by CASA.
The directives aim to ensure the safety and airworthiness of the Twin Commander series aeroplanes by addressing specific fatigue-related issues in the wing spar lower cap assemblies. CASA retains the authority to enforce these regulations and may take action against operators who fail to comply with the specified requirements. In cases of significant non-compliance, CASA can impose maximum penalties as outlined in the Civil Aviation Act 1988, which can include substantial fines and other enforcement measures.