AD/F100/82 Amdt 1 Piccolo Tube Peri-Seals (Cth)
AIRWORTHINESS DIRECTIVE
On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/F100/82 and issues the following AD under subregulation 39.001(1) of CASR 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/F100/82 Amdt 1 | Piccolo Tube Peri-Seals | 11/2007 |
Applicability: | Fokker Aircraft B.V. Model F28 Mark 0070 and Mark 0100 aircraft, all serial numbers, unless modified per Fokker Service Bulletin SBFI00-30-022. |
Requirement: | 1. Inspect the Piccolo Tubes and their surrounding area and replace the Peri-seals in accordance with Part 3 Accomplishment Instructions of Fokker Service Bulletin SBF100-30-028 dated 18 May 2006 or a later NAA approved revision. 2. Do not install a spare wing leading edge section on any of the aircraft affected by this directive, unless it has been modified in accordance with CSB Note: EASA AD 2007-0229 dated 25 August 2007 refers. This AD supersedes |
Compliance: | 1. Remains unchanged as: Within the next 4,000 flight hours or 24 calendar months after the effective date of 23 November 2006 (the original issue of this AD), whichever occurs first, unless previously accomplished. 2. From 15 August 2008. |
| This Amendment becomes effective on 25 October 2007. | |
Background: | In 1997, Fokker introduced a new type of Peri-seal (SBF100-30-022). The old type was known to be subject to deterioration, which, in combination with improper installation, can cause leakage of hot wing anti-icing air from the Peri-seal housing. This results in an uncontrolled flow of high-pressure hot air to enter the forward (anti-icing) plenum chamber of the wing leading edge, potentially damaging the anti-icing barrier webs. Subsequently, the wing auxiliary spar can also be damaged by high-pressure hot air. Analysis at the time showed that any resulting damage (known to occur at inboard positions only) would not affect the wing load capability. For this reason, the modification was not classified as MANDATORY and no AD action was warranted. However, through a recent occurrence, it was discovered that deterioration of the Peri-seals enables the piccolo tubes to vibrate, resulting in a broken piccolo tube. In this case, the location of the failure was more outboard than previous occurrences. This condition, if not corrected, may cause heat damage to the front spar that potentially affects the wing’s load capability. |
| Since an unsafe condition has been identified that is likely to exist or develop on aircraft of this type design, this Airworthiness Directive requires inspection of the Piccolo Tubes and the surrounding structure to establish correct installation, as well as the replacement of the 460-series Peri-seals by the improved 600-series, which have a higher temperature limit. A new MRB task will be introduced to require the repetitive replacement (life limit) of the new Pen-seals to prevent long-term degradation. Since the issuance of original issue of this AD, Fokker has developed a modification, published as Component Service Bulletin (CSB) D14000-57-007, for spare wing leading edge sections that may still contain the 460-series Peri-seals. For that reason, this AD retains the requirements of AD NL-2006-011 and adds a limit for the allowed use of unmodified wing leading edge section as replacement part. The original issue of this AD became effective on 23 November 2006. |
Charles Lenarcic
Delegate of the Civil Aviation Safety Authority
10 September 2007
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