COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Cessna 206 Series Aeroplanes
AD/CESSNA 206/3
Amdt 3
Wing Rear Spar 1/90
Applicability: All models fitted with rear spar assembly P/N 1220050-1, -2, -23, -24, -25 or -26.
Note: These part numbers are in aircraft serial numbers 206-0001 to 206-0275, U206-0276 to U206-1367, and P206-0001 to P206-0597; excepting of course those aircraft that have had rear spar assemblies replaced with later part numbers.
Requirement: Visually inspect each main plane rear spar web for fatigue cracking at the root attachment area and the upper flange of the rear spar channel at the outer end of the attachment fittings. These cracks originate in the radius which is located beneath the attachment fittings. This inspection shall be carried out using a magnifying glass of at lease 4X magnification or alternatively, a device such as the “Syte Ade” may be employed. Since the trailing edge root end rib fits closely to the spar, it may be difficult to detect possible cracks, therefore, where doubt exists, the trailing edge root end rib shall be removed for more detailed inspection.
Note: The affected area is illustrated in Rex Aviation Technical Memorandum No. 12 dated 10 May 1960.
Compliance: Within 500 hours time in service after 25 January 1990, and thereafter at intervals not exceeding 500 hours time in service.
Background: There have been several reports of cracks in the rear spar near the attachment fitting, including at least one fatal accident, in another model that uses a similar design of spar assembly.
The problem seems to be confined to the early design rear spars. Later spars have a thicker web and additional doublers. Amendment 3 changes the applicability of this Directive to clarify that only the early part number rear spars need to be inspected.
The inspection interval has been extended to 500 hours based on service experience.
Overview
The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses safety concerns for aircraft through the issuance of Airworthiness Directives. One such directive, AD/CESSNA 206/3 Amendment 3, targets the inspection of the wing rear spar of Cessna 206 Series Aeroplanes. This directive was enacted to mitigate the risk of fatigue cracking in the rear spar web and flange, which has been identified as a safety issue, particularly in older models. The policy objective behind this directive is to ensure that these aircraft remain airworthy by mandating regular inspections to detect and address potential structural weaknesses before they lead to catastrophic failures. The amendment narrows the scope of applicability to specific early part number rear spars, reflecting an effort to focus resources on the areas of greatest risk.
The Civil Aviation Safety Authority, under the authority of the Australian Government, issued this directive to enhance safety standards and compliance in the aviation industry. The directive aims to prevent the recurrence of incidents related to structural failure in the specified aircraft models by setting a clear inspection protocol and timeframe, thereby contributing to the overarching goal of maintaining the highest safety standards in Australian civil aviation.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 concerning the Civil Aviation Safety Authority Schedule of Airworthiness Directives, apply to all Cessna 206 Series aeroplanes fitted with specific rear spar assembly part numbers. The regulation targets a particular group of aircraft, namely those equipped with rear spar assemblies identified by part numbers 1220050-1, -2, -23, -24, -25, and -26, which are found in the serial number ranges 206-0001 to 206-0275, U206-0276 to U206-1367, and P206-0001 to P206-0597. Aircraft that have had these rear spar assemblies replaced with newer part numbers are exempted from this directive. The regulation mandates a visual inspection for fatigue cracking in the rear spar webs and flanges, performed with appropriate magnification tools, and requires compliance with these inspections within 500 hours of service after 25 January 1990 and subsequently at intervals not exceeding 500 hours of service. This regulatory action is a response to reported incidents of spar cracking, including a fatal accident, and aims to ensure the continued airworthiness of the affected aircraft.
Key Provisions
The Civil Aviation Regulations 1998, specifically under Part 39, contain a schedule of airworthiness directives that mandate specific inspections and maintenance procedures for certain aircraft models. For instance, AD/CESSNA 206/3 Amendment 3 (AD/CESSNA 206/3/Amdt 3) concerns the Cessna 206 Series aeroplanes and focuses on the wing rear spar. The directive applies to all models equipped with rear spar assemblies bearing part numbers 1220050-1, -2, -23, -24, -25, or -26, which are found in aircraft serial numbers ranging from 206-0001 to 206-0275, U206-0276 to U206-1367, and P206-0001 to P206-0597. However, it excludes those aircraft that have already had their rear spar assemblies replaced with later part numbers. The primary requirement of this directive is to conduct a visual inspection of the main plane rear spar web for any fatigue cracking at the root attachment area and the upper flange of the rear spar channel at the outer end of the attachment fittings. The inspection should focus on the radius beneath the attachment fittings. The use of a magnifying glass with at least 4X magnification or a device like the "Syte Ade" is recommended. If there is any doubt about the presence of cracks, the trailing edge root end rib should be removed for a more detailed inspection.
The obligations imposed by this directive are clear and specific. Operators of the affected Cessna 206 Series aeroplanes must ensure that the visual inspections are conducted meticulously. The inspections are required within 500 hours of time in service after 25 January 1990, and then at intervals not exceeding 500 hours of time in service thereafter. Failure to comply with these inspection requirements could result in the aircraft being deemed unairworthy, which could lead to severe consequences including grounding of the aircraft until the necessary inspections and repairs are performed. The directive also provides a reference to Rex Aviation Technical Memorandum No. 12 dated 10 May 1960, which illustrates the affected areas for clarity.
In terms of potential penalties and consequences, the Civil Aviation Regulations do not explicitly detail specific offences or penalties related to this airworthiness directive within the provided text. However, non-compliance with airworthiness directives can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions may include fines, penalties, or more severe measures such as the suspension or revocation of the aircraft's certificate of airworthiness. Additionally, failure to adhere to these directives could result in legal liability in the event of an accident or incident caused by undetected structural failure in the rear spar.