AD 2012-22-09 Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

This AD becomes effective December 20, 2012.

(1) The Manager, Boston Aircraft Certification Office, FAA, may approve AMOCs for this AD. Send your proposal to: Nicholas Faust, Aviation Safety Engineer, Boston Aircraft Certification Office, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7763; email nicholas.faust@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, we suggest that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office before operating any aircraft complying with this AD through an AMOC.

Joint Aircraft Service Component (JASC) Code: 5340, Fuselage Main, Attach Fittings.

(1) For helicopters with 500 or more hours time-in-service (TIS), within 25 hours TIS and thereafter at intervals not to exceed 10 hours TIS, inspect each T/R pylon for a crack, damage, corrosion, or a loose or missing fastener in accordance with the Accomplishment Instructions, paragraph 3.A.(4)(a) through paragraph 3.A.(4)(f), and referring to Figure 1 of Sikorsky Alert Service Bulletin (ASB) No. 92-53-001, dated June 23, 2008, except that you are not required to contact Sikorsky Customer Service Engineering per paragraph 3.A.(4)(c) 1 of ASB 92-53-001, dated June 23, 2008. (2) If there is a crack, damage, corrosion, or a loose or missing fastener, before further flight, either: (i) If within allowable tolerances, repair each crack and each area of damage or corrosion and replace any loose or missing fastener; or (ii) Replace the T/R pylon, (P/N) 92000-06102-041, with T/R pylon, P/N 92070-20058-042, as follows: (A) Conduct the Total Indicated Run-out procedure on the No. 4 and No. 5 T/R drive shafts and remove the T/R pylon; and (B) Install the doubler, P/N 92070-20087-101, as follows: ( 1 ) For helicopters, serial numbers (S/Ns) 920006 through 920082, on the aft shear deck tunnel assembly, P/N 92204-05103-041 or -045, in accordance with the Accomplishment Instructions, paragraph 3.B.(1) through 3.B.(30) and while referring to Figures 1, 2, and 4 of Sikorsky ASB No. 92-53-004B, Revision B, dated June 21, 2011 (92-53-004B). ( 2 ) For helicopters, S/Ns 920083 through 920124, on the aft shear deck tunnel assembly, P/N 92204-05103-043, in accordance with the Accomplishment Instructions, paragraph 3.C.(1) through 3.C.(21) and referring to Figures 3 and 4 of ASB 92-53-004B. (3) If there is no crack in the T/R pylon, replace T/R pylon, P/N 92000-06102-041, with T/R pylon, P/N 92070-20058-042, and install doubler, P/N 92070-20087-101, on the aft shear deck tunnel assembly as specified in paragraphs (2)(ii)(A) through (2)(ii)(B) of this AD, according to the following: (i) For a T/R pylon with 3,750 or more hours TIS, replace and install doubler within 12 months. (ii) For a T/R pylon with 1,500 through 3,749 hours TIS, replace and install doubler within 24 months. (iii) For a T/R pylon with 1,499 or less hours TIS, replace and install doubler within 36 months. (4) Replacing T/R pylon, P/N 92000-06102-041, with T/R pylon, P/N 92070-20058-042, and installing internal tail cone doubler, P/N 92070-20087-101, on the aft shear deck tunnel assembly, constitutes terminating action for the requirements of this AD.

This AD defines the unsafe condition as a loose or missing fastener, a crack, damage, or corrosion on the T/R pylon that could result in failure of the T/R pylon or other T/R components, and subsequent loss of control of the helicopter.