AD/FU24/64 Fin and Leading Edge (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.

Airparts (NZ) Ltd. FU 24 Series Aeroplanes

AD/FU24/64 Fin and Leading Edge 13/2007 DM

Applicability:

All Model FU-24 aircraft.

Requirement:

1 and 2.  Visual Inspection.

Inspect the fin for condition, security, and damage in accordance with the requirements in Chapter 05 page 25 of the FU-24-950 Series Maintenance Manual.

In order to carry out this visual inspection, all non-transparent protective coatings and their adhesive must be removed.  This includes previously approved modifications such as, but not limited to, James Aviation Modification JA/FU24/M258.

3.    Detailed Inspection.

Perform a detailed visual inspection of the leading edge skin in the area detailed in Figure 1 to detect cracking, corrosion, scratches, dents, creases, or buckling.

Inspect the entire leading edge down to the forward attach fitting.  If the aircraft has been modified by the addition of dorsal fin extensions, these must be removed in order to inspect the obscured areas of the fin.

Inspect the fin skin for corrosion and cracks paying particular attention to the centre rib rivet holes and the skin joint at the fin base.

Inspect the fin forward attachment point for corrosion and remove the fin tip and inspect the top rib for cracks at the skin stiffener cut outs.

Inspection and maintenance requirements for the vertical stabiliser are detailed in the FU-24-950 Series Maintenance Manual, Chapters 05 and 55.

Damage detected during any inspection must be repaired using an approved repair scheme before further flight.

The following transparent polyurethane protective tapes have been assessed as suitable for use to re-protect the leading edge, and may remain in situ for subsequent inspections, provided they are sound, and in a condition to permit visual inspection of the skin beneath them.

Manufacturer           Product

3M   8591, or 8671, 8672, and 8681HS (aeronautical grade)

Scapa   Aeroshield P2604 (transparent)

Do not trim product in situ, as score damage to the skin may lead to fatigue failure.

Note 1:  This Directive amplifies the Check 1 and Check 2 visual inspection requirements for the vertical stabiliser as detailed in Chapter 05 page 25 of the
FU-24-950 Series Maintenance Manual.

Figure 1: Fin Leading Edge Inspection

Note 2:  NZ CAA AD DCA/FU24/176C refers.

Compliance:

1.    Visual inspection by the pilot: After every last flight of the day.

2.    Visual inspection by maintenance personnel: Within 50 hours time in service after 8 November 2007, and thereafter at intervals not to exceed 50 hours time in service.

3.    Detailed inspection: Within 100 hours time in service after 8 November 2007, and thereafter at intervals not to exceed 100 hours time in service.

The Requirement 1 visual inspection at every last flight of the day may be performed and certified by the pilot in command who has been trained to do the inspection by an appropriately qualified person.

This Airworthiness Directive becomes effective on 8 November 2007.

Background:

The actions required by this Directive are intended to prevent possible in-flight failure of the vertical fin, with consequent loss of control of the aircraft.

David Villiers
Delegate of the Civil Aviation Safety Authority

7 November 2007