AD/F100/77 Main Landing Gear Main Fitting 4 (Cth)

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 39.001(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/F100/77 Main Landing Gear Main Fitting - 4 4/2006

Applicability:

Model F.28 Mk. 0070 and Mk. 0100 aircraft, all serial numbers, if equipped with Messier-Dowty (formerly Dowty Aerospace Gloucester) Main Landing Gears.

Requirement:

1.    For all installed MLG Main Fitting units, except as indicated in Requirement 2 of this Directive, inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of Messier-Dowty Service Bulletin (SB) F100-32-111, dated 20 December 2005, or later EASA approved revision.

2.    For new MLG Main Fitting units and MLG Main Fitting units on which both bores have been reworked as required by CAA-NL AD 2002-115/2 (AD/F100/55 Amdt 1) or NL-2005-002 (AD/F100/64), inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of SB F100-32-111, or later EASA approved revision.

3.    Thereafter, inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of SB F100-32-111, or later EASA approved revision.

Whenever cracks are found, determine whether (and for how many) flights may be continued, before rework or replacement, in accordance with the crack size and location thresholds as listed in Fokker Services SBF100-32-146, dated
2 February 2006, or later EASA approved revision.

4.    Whenever, following a crack finding (or for any other reason), a MLG Main Fitting has been reworked (both bores) or replaced by a new MLG Main Fitting, inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of SB F100-32-111, or later EASA approved revision.

5.    No Dowty Aerospace Gloucester or Messier-Dowty MLG Main Fitting unit (except for new or reworked units, as indicated in Requirements 2 or 4 of this Directive) may be installed as a replacement part, unless it has been inspected, and as necessary, reworked in accordance with SB F100-32-106, dated
18 February 2005 or SB F100-32-111; or later EASA approved revisions.

Irrespective of the results, within 7 calendar days after each inspection as required by Requirements 1, 2, 3, and 4 of this Directive, report all findings to Fokker Services using the questionnaire attached to Fokker Services
SBF100-32-146.

Note:  CAA-NL AD NL-2006-003 refers.

Compliance:

1.    Within the next 2,000 flight cycles since the last inspection in accordance with Messier-Dowty SB F100-32-106 and Fokker Services SBF100-32-141, as required by AD NL-2005-002 (AD/F100/64), or within the next 4 months after 13 April 2006, whichever occurs later.

2.    Within 4,000 flight cycles since new (installation) or rework, as applicable.

3.    At intervals not to exceed 2,000 flight cycles.

4.    Within 4,000 flight cycles since new (installation) or rework, as applicable, and thereafter at intervals not to exceed 2,000 flight cycles.

5.    As of the effective date of this Directive.

This Airworthiness Directive becomes effective on 13 April 2006.

Background:

Two cases have been reported of Fokker 100 aircraft, being moved backward for maintenance, suffering failure of a Main Landing Gear Main Fitting upon brake application.  CAA-NL previously issued AD 2002-115/2 and NL-2005-002 to prevent and remedy this problem.  Both ADs still apply and require one-time inspections, an AFM change and the introduction of a placard that prohibit application of the brakes during any backwards movement of the aircraft.  This Directive requires the introduction of a repetitive inspection for cracks and rework, as necessary.

David Punshon
Delegate of the Civil Aviation Safety Authority

1 March 2006