AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Fokker F100 (F28 Mk 100) Series Aeroplanes
AD/F100/51 Vertical Stabiliser Torsion Box - 2 7/2002
Applicability: Model F.28 Mk.0100 aircraft, serial numbers 11244 through 11460, 11463 through 11469, 11471, 11474 through 11483, 11489, 11490, 11491, 11497, 11498, 11499,
11501, 11502, 11504, 11506, 11507, 11512 through 11515, 11517, and 11520.
Requirement: Cold expand the 12 hi- lok bolt holes at the Rib 5.0 position of the vertical stabiliser torsion box, in accordance with Parts 1, 2, and 3 of the Accomplishment Instructions, as applicable, of Fokker Service Bulletin (SB) F100-55-023, dated 3 January 1995.
Note: Netherlands CAA AD 1995-017 refers.
Compliance: 1. For aircraft which have already been in-service modified to post SB F100-55- 018-configuration:
Before accumulating 10,000 flight cycles since the accomplishment of the modification in accordance with Fokker SB F100-55-018 (as required by AD 93- 069); or,
2. For aircraft which are still in pre-SB F100-55-018-configuration:
Concurrent with the accomplishment of the modification in accordance with Fokker SB F100-55-018 (as required by AD 93-069); or,
3. For aircraft which have had SB F100-55-018 factory incorporated: Before accumulating 10,000 flight cycles since new.
This Airworthiness Directive becomes effective on 11 July 2002.
Fokker F100 (F28 Mk 100) Series Aeroplanes
AD/F100/51 (continued)
Background: Netherlands Airworthiness Directive 93-069 (AD/F100/17) was issued to prevent cracks in the vertical stabiliser torsion box, and requires the accomplishment of Fokker SB F100-55-018, which introduces support brackets on Rib 5.0. More recent full-scale fatigue tests, however, have revealed cracks in Rib 5.0, due to this modification. This condition, if not corrected, produces a too rapid change in structural strength and may lead to consequential cracking of the vertical stabiliser struc ture. This Directive requires an additional modification that introduces cold- expanded bolt holes in the torsion box at Rib 5.0 of the vertical stabiliser.
David Alan Villiers
Delegate of the Civil Aviation Safety Authority 31 May 2002
The above AD is notified in the Commonwealth of Australia Gazette on 19 June 2002.
Overview
The Airworthiness Directive AD/F100/51 issued by the Civil Aviation Safety Authority (CASA) in 2002 addresses an identified safety issue with the Fokker F100 (F28 Mk 100) Series Aeroplanes. This directive was introduced to rectify the unsafe condition caused by cracks in the vertical stabiliser torsion box, a problem initially identified and partially addressed by Netherlands Airworthiness Directive 93-069 (AD/F100/17). Despite the earlier modification, further testing revealed that the modification could still lead to structural weaknesses and consequential cracking. The policy objective of this directive is to enhance the safety of the specified Fokker F100 aircraft models by requiring the cold expansion of bolt holes at the Rib 5.0 position of the vertical stabiliser torsion box, as detailed in Fokker Service Bulletin F100-55-023. This measure is designed to prevent the identified structural issues and ensure the continued airworthiness of the affected aircraft.
Scope and Application
The Airworthiness Directive issued under the Civil Aviation Regulations 1998 applies specifically to Fokker F100 (F28 Mk 100) series aeroplanes with certain serial numbers, which are detailed in the applicability section of the directive. These aircraft must comply with the specified requirements for the vertical stabiliser torsion box, which involves cold expanding the 12 hi-lok bolt holes at the Rib 5.0 position. This directive is issued by the delegate of the Civil Aviation Safety Authority and applies across the Commonwealth of Australia, as evidenced by its notification in the Commonwealth of Australia Gazette. The compliance criteria depend on whether the aircraft is already in-service modified, still in the pre-modification configuration, or has the modification factory incorporated, with a compliance deadline set in relation to flight cycles. This directive, which came into effect on 11 July 2002, aims to address the unsafe condition identified through recent fatigue tests, ensuring the structural integrity of the vertical stabiliser in the specified Fokker F100 aircraft models.
Key Provisions
The key provisions of the Airworthiness Directive (AD) for Fokker F100 (F28 Mk 100) Series Aeroplanes, as issued by the Civil Aviation Safety Authority (CASA) delegate, are outlined in AD/F100/51. This AD mandates specific actions to address an unsafe condition related to the vertical stabiliser torsion box. The affected aircraft are those in the Fokker F100 series with serial numbers ranging from 11244 through 11460, 11463 through 11469, and so forth, up to 11520. The requirement is to cold expand the 12 hi-lok bolt holes at the Rib 5.0 position of the vertical stabiliser torsion box, as detailed in Parts 1, 2, and 3 of the Accomplishment Instructions of Fokker Service Bulletin (SB) F100-55-023 dated 3 January 1995. The AD references Netherlands CAA AD 1995-017 for additional context.
The AD imposes specific obligations on the parties governed by it. Aircraft owners and operators must ensure that the cold expansion modification is carried out in accordance with the instructions provided in Fokker SB F100-55-023. For aircraft that have already undergone the modification to post SB F100-55-018 configuration, this must be done before accumulating 10,000 flight cycles since the modification. For aircraft still in pre-SB F100-55-018 configuration, the modification must be performed concurrently with the SB F100-55-018 modification. Aircraft that have had SB F100-55-018 factory incorporated must undergo the bolt hole modification before accumulating 10,000 flight cycles since new. Compliance with these requirements is crucial to address the identified unsafe condition.
Failure to comply with the AD may result in significant consequences. The AD does not explicitly state specific penalties or offences; however, non-compliance with an AD can lead to enforcement actions by CASA, including fines, suspension, or revocation of the aircraft's certificate of airworthiness. The seriousness of the condition, which involves structural integrity, implies that non-compliance could also have severe safety implications. It is imperative that all stakeholders adhere to the AD to ensure the continued airworthiness and safety of the affected Fokker F100 aircraft.