COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Fokker F27 Series Aeroplanes
AD/F27/142
Amdt 1
Main Landing Gear Actuating Ram 5/98
Applicability: All Fokker F27 Mk 100 through Mk 700 series aircraft fitted with Dunlop main landing gear actuating ram, P/N AC67132, AC67134, AC67848 or AC67850.
Requirement: Modify the main landing gear actuating ram in accordance with Dunlop Equipment Division SB 32-1142 dated October 22, 1996, or Dunlop Aviation Australia (DAA) Service Bulletin 36-24 dated May 21, 1984.
Note: RLD AD BLA nr 1996-142(A) dated November 29, 1996, and Fokker SB F27/32-168 dated October 23, 1996, refers.
Compliance: Unless previously accomplished, at next repair or overhaul or within the next 4000 hours time in service or 24 calendar months, whichever occurs first.
This amendment becomes effective on 23 April 1998.
Background: Several operators have reported broken main landing gear lockstruts. Investigation by Fokker has confirmed failure of the lockstrut was due to loss of damping within the main landing gear actuating ram. To dampen the gear movement during extension the actuating ram is equipped with a damping chamber filled with silicon oil which is forced through a restrictor during ram extension. If a bobbin “O” ring seal fails then the silicon oil can leak past the seal and this may not be noticed during routine maintenance. Silicon oil loss usually leads to a gradual loss in damping which can be detected by an increase in landing gear extension speed or shaking of the aircraft at gear extension.
Dunlop Australia in 1984 developed a modification that also addresses the problem, however it changes the actuator ram seal configuration preventing fitment of the DED modification. This amendment reflects the suitability of the Dunlop Australia modification.
The original issue of this airworthiness directive became effective on 27 March 1997.
Overview
The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), play a crucial role in ensuring the safety of civil aviation within Australia. This regulatory framework includes Part 39 - 105, which details specific airworthiness directives aimed at maintaining the safety standards of aircraft. One such directive, AD/F27/142 Amendment 1, pertains to the Fokker F27 series aeroplanes and was enacted to address issues with the main landing gear actuating ram. This directive became effective on 23 April 1998, following reports of broken main landing gear lockstruts due to the loss of damping in the actuating ram. The directive mandates modifications to the ram to rectify the identified safety issue, ensuring compliance with specified service bulletins from Dunlop. The policy objective behind this directive is to mitigate the risk of gear failure and enhance the overall safety of Fokker F27 aircraft during operation.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, which pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, applies to all Fokker F27 Mk 100 through Mk 700 series aircraft equipped with Dunlop main landing gear actuating rams identified by the part numbers AC67132, AC67134, AC67848, or AC67850. This directive is part of the overarching legislative framework aimed at ensuring the safety and airworthiness of aircraft within Australia's jurisdiction. The directive mandates that the specified main landing gear actuating rams must be modified in accordance with Dunlop Equipment Division Service Bulletin 32-1142 dated October 22, 1996, or Dunlop Aviation Australia Service Bulletin 36-24 dated May 21, 1984. Compliance with this directive requires the modification to be carried out at the next repair or overhaul of the aircraft, or within the next 4000 hours of time in service, or 24 calendar months, whichever comes first. This amendment came into effect on 23 April 1998, addressing an issue where the loss of damping within the actuating rams was found to be due to a failure in the bobbin “O” ring seal, leading to a gradual loss in damping and potential safety risks during landing gear extension.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives (AD) for various aircraft. One such directive, AD/F27/142 Amendment 1, concerns the Fokker F27 Series Aeroplanes. This particular directive applies to all Fokker F27 aircraft from the Mk 100 to Mk 700 series that are equipped with Dunlop main landing gear actuating rams bearing part numbers AC67132, AC67134, AC67848, or AC67850 (section 1). The directive mandates that these main landing gear actuating rams must be modified in accordance with Dunlop Equipment Division Service Bulletin 32-1142 dated October 22, 1996, or Dunlop Aviation Australia Service Bulletin 36-24 dated May 21, 1984 (section 2). This modification is to address issues related to the loss of damping within the actuating ram, which can lead to failures such as broken main landing gear lockstruts.
Operators of the affected Fokker F27 aircraft are required to comply with this directive by modifying the main landing gear actuating ram. The modification must be carried out at the next repair or overhaul of the aircraft, within 4000 hours of time in service, or within 24 calendar months, whichever occurs first. This directive was amended to become effective on April 23, 1998 (section 3). The need for this modification arises from incidents where the damping chamber, filled with silicon oil, experienced a loss of oil due to a failed bobbin “O” ring seal. This loss of oil leads to a gradual reduction in damping, which can be detected by an increase in landing gear extension speed or shaking of the aircraft during gear extension.
Failure to comply with this AD could result in serious safety issues, as the loss of damping within the actuating ram can lead to catastrophic failure of the main landing gear. The regulations impose significant obligations on aircraft operators to ensure the airworthiness of their aircraft. Non-compliance with these airworthiness directives can result in penalties and enforcement actions by CASA. Such actions may include fines, suspension of airworthiness certificates, or other regulatory measures to ensure compliance and maintain safety standards in civil aviation (section 4). The maximum penalties for non-compliance with these regulations can vary, but they are designed to enforce adherence to critical safety requirements.