Airworthiness Directive · Amendment 39-18387 · Tail rotor system
Bell Helicopter Textron Canada Limited
Superseded. A later AD replaced this one: AD 2020-17-10. Comply with the one in force.
This AD applies to Bell Helicopter Textron Canada Limited Model 429 helicopters with a tail rotor (T/R) pitch link (link) part number (P/N) 429-012-112-101, -101FM, -103, or -103FM installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron Canada Limited (Bell) Model 429 helicopters. This AD requires inspecting each tail rotor (T/R) pitch link (link) bearing bore for corrosion and pitting and either replacing the T/R link or applying sealant. This AD also requires a recurring inspection of the sealant and repeating the inspections for corrosion and pitting if any sealant is missing. This AD is prompted by an incident in which a helicopter experienced an in-flight failure of a T/R link. These actions are intended to detect corrosion or pitting and to prevent failure of a T/R link and subsequent loss of control of the helicopter.
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 429-012-112-103, within 10 hours time-in-service (TIS):
(i) Remove each T/R link assembly. 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 inspect 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 links 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 paragraph (e)(1)(i) through (e)(1)(iii) of this AD before further flight.
(3) Do not install T/R link P/N 429-012-112-101 or -103 on any helicopter before complying with the actions in paragraph (e)(1) 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.
