Airworthiness Directive · Amendment 39-21215 · Tail rotor system
Bell Helicopter Textron Canada Limited Helicopters
This AD applies to Bell Helicopter Textron Canada Limited Model 429 helicopters with a tail rotor (T/R) pitch link assembly (link) part number (P/N) 429-012-112-101, -101FM, -103, -103FM, -111, -111FM, -113, or -113FM installed, certificated in any category.
The FAA is superseding Airworthiness Directive (AD) 2016-02-06 for Bell Helicopter Textron Canada Limited (Bell) Model 429 helicopters. AD 2016-02-06 required inspecting certain tail rotor (T/R) pitch link bearing bores for corrosion and pitting. AD 2016-02-06 also required a repetitive inspection of the sealant and repeating the inspections for corrosion and pitting if any sealant is missing. This new AD retains the requirements of AD 2016-02-06, expands the applicability, and adds a repetitive inspection. This AD was prompted by an FAA determination that additional part-numbered T/R pitch link assemblies (links) are affected by the same unsafe condition and that an additional repetitive inspection is necessary to address the unsafe condition. The actions of this AD are intended to address an unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) For T/R link P/N 429-012-112-101 and -103, within 10 hours time-in-service (TIS):
(i) Remove each T/R link. Prior to cleaning the T/R link bearing bores, using 10X or higher power magnification, inspect each T/R link bearing bore for aluminum oxide corrosion extruding from between the roll staked lip of the bearing outer race and the link bearing bore. Aluminum oxide corrosion appears as a white crystalline material in contrast with the black finish and any accumulated soot. An example of this corrosion is shown in Figure 1 of Bell Helicopter Alert Service Bulletin 429-15-26, dated December 7, 2015 (ASB 429-15-26).
(ii) If there is any aluminum oxide corrosion, replace the T/R link before further flight.
(iii) If there is no aluminum oxide corrosion, clean each T/R link bearing bore with isopropyl alcohol, and using 10X or higher power magnification, inspect each cleaned T/R link for pitting.
(A) If there is any pitting, replace the T/R link before further flight.
(B) If there is no pitting, apply corrosion preventative sealant by following the Accomplishment Instructions, paragraph 5. of Part I, of ASB 429-15-26.
(2) For all T/R link P/Ns listed in paragraph (a) of this AD, within 50 hours TIS, and thereafter at intervals not to exceed 50 hours TIS, using 10X or higher power magnification, inspect each T/R link bearing bore for missing corrosion preventative sealant. If any corrosion preventative sealant is missing, perform the actions in paragraphs (f)(3)(i) and (ii) of this AD before further flight.
(3) For all T/R link P/Ns listed in paragraph (a) of this AD, within 12 months since date of manufacture, except if paragraphs (f)(1)(i) through (iii) of this AD have already been done for T/R link P/N 429-012-112-101 or -103 within the last 12 months and except if paragraph (f)(3)(i) and (ii) of this AD have already been done for T/R link P/N 429-012-112-101FM, -103FM, -111, -111FM, -113, or -113FM within the last 12 months; and thereafter for all T/R link P/Ns listed in paragraph (a) of this AD at intervals not to exceed 12 months:
(i) Remove each T/R link; and
(ii) Remove all corrosion preventative sealant, and perform the actions in paragraphs (f)(1)(i) through (iii) of this AD.
(4) After the effective date of this AD:
(i) Do not install T/R link P/N 429-012-112-101 or -103 on any helicopter before complying with the actions in paragraphs (f)(1)(i) through (iii) of this AD.
(ii) Do not install T/R link P/N 429-012-112-101FM, 103FM, -111, 111FM, -113, or -113FM on any helicopter before complying with the actions in paragraph (f)(2) of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
