AD/S-76/66 Amdt 1 Main Landing Gear Positioning Rod Assembly (Cth)

AIRWORTHINESS DIRECTIVE

On the commencement date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below repeals Airworthiness Directive (AD) AD/S-76/66 and issues the following AD under subregulation 39.001 (1) of CASR and subsection 33 (3) of the Acts Interpretation Act 1901. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct an 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.

Sikorsky Aircraft Corporation S-76 Series Helicopters

AD/S-76/66 Amdt 1 Main Landing Gear Positioning Rod Assembly 17/2019

Applicability:

All Sikorsky S-76A, S-76B and S-76C model helicopters with the following parts installed:

a.     Positioning rod assembly Part Number (P/N) 1945E-31A or 2071-31, or

b.    Side brace rod end P/N 1945E-235 or 2071-235.

Requirement:

1.    a.     Inspect the positioning rod assembly and side brace rod end for corrosion in accordance with Section 2, Accomplishment Instructions, in BFGoodrich Service Bulletin (SB) No. 76A-32-03, Revision 1, as in force on 15 September 2000.

b.    Replace any applicable part that is corroded with a serviceable part.

2.    a.     If the positioning rod assembly or side brace rod end were inspected and re-assembled in accordance with BFGoodrich Component Maintenance Manual with Illustrated Parts List 1945/2071 Series Main Landing Gear, No. 32‑10‑01, as in force from time to time, within the period of 24 months before the commencement of this AD, inspect the positioning rod assembly and side brace rod end in accordance with Section 2 of SB 76A-32-03 Revision 1, as in force on 15 September 2000.

b.    Replace any applicable part that is corroded with a serviceable part.

3.    a.     For side brace rod ends that are not re-assembled with Mastinox sealant or re-assembled with Mastinox sealant but without cadmium plate restoration; inspect the positioning rod assembly and side brace rod end for corrosion in accordance with Section 2 of SB 76A-32-03 Revision 1, as in force on 15 September 2000.

b.    Replace any applicable part that is corroded with a serviceable part.

4.    a.     For side brace rod ends assembled with Mastinox sealant and cadmium plate restoration or for side brace rod ends re-assembled with Mastinox but that did not previously require rework due to corrosion, inspect the positioning rod assembly and side brace rod end for corrosion in accordance with Section 2 of SB 76A-32-03 Revision 1, as in force on 15 September 2000.

b.    Replace any applicable part that is corroded with a serviceable part.

Note 1:  Federal Aviation Administration of USA AD 2001-01-04 Amendment 39-12074 refers.

Note 2:  The words “as in force from time to time” require compliance with the most recent version of the referenced document.

Compliance:

1.    a.     Unless previously accomplished, within 14 days after the commencement of this AD.

b.    Before further flight.

2.    a.     Unless previously accomplished, within 42 days after the commencement of this AD.

b.    Before further flight.

3.    a.     At intervals not to exceed 90 days.

b.    Before further flight.

4.    a.     At intervals not to exceed 12 months or 1,500 hours’ time in service, whichever occurs first.

b.    Before further flight.

This AD commences on 23 August 2019.

Background:

The FAA received a report of a landing gear collapse cause by corrosion due to dissimilar metals in the landing gear rod end.  The actions specified by this Directive are intended to detect corrosion of the threaded joint in the rod assembly to prevent a collapse of the landing gear, and subsequent loss of control of the helicopter during landing.

Amendment 1 of this AD is issued to expand the applicability of the AD by removing the aircraft serial number range, thereby making the AD applicable to all S‑76 helicopters that have the applicable part numbers for positioning rod assembly or side brace rod ends installed.

This amendment action is considered necessary to address the possibility that the affected parts can be installed on all S-76 helicopters, including those models of later serial numbers.  This possibility is confirmed by the effectivity of BFGoodrich Service Bulletin 76A-32-03, Revision 1, dated 15 September 2000 which includes all S-76A, S-76B and S-76C helicopters fitted with the affected parts.

Pieter van Dijk
Delegate of the Civil Aviation Safety Authority

13 August 2019