Airworthiness Directive · Amendment 39-19862 · Tail rotor system
Bell Helicopter Textron Canada Limited Helicopters
This AD applies to Bell Helicopter Textron Canada Limited Model 429 helicopters, certificated in any category, with a serial number 57001 through 57343 inclusive, 57346 through 57349 inclusive, 57352 through 57356 inclusive, and 57362, with a curvic coupling part number 429-012-120-101 installed.
The FAA is adopting a new airworthiness directive (AD) for certain Bell Helicopter Textron Canada Limited (Bell Canada) Model 429 helicopters. This AD requires inspecting a certain part-numbered curvic coupling for proper engagement and depending on the inspection results, inspecting for play, inspecting the curvic coupling teeth, inspecting the flapping bearing teeth, replacing parts, performing a rigging check, and reporting information. This AD was prompted by a report of disengaged teeth of a curvic coupling due to improper installation. 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) Within 10 hours time-in-service, using a light source, flap the inboard and outboard T/R blades to inspect for proper engagement of the inboard and outboard curvic coupling teeth with the inboard and outboard flapping bearing teeth as shown in Figure 2 of Bell Alert Service Bulletin 429-19-45, dated April 16, 2019 (ASB 429-19-45).
(i) If the teeth are not properly engaged, before further flight, remove the T/R hub and blade assembly and do the following:
Note to paragraph (e)(1)(i) of this AD: Figure 1 of ASB 429-19-45 shows an example of improperly engaged teeth.
(A) Inspect the inboard flapping bearing teeth and the curvic coupling teeth that mate to them for a crack, wear, mechanical damage, and corrosion. If there is a crack, wear, mechanical damage, or corrosion on the teeth, before further flight, replace with an airworthy part.
(B) Inspect the outboard flapping bearing teeth and the curvic coupling teeth that mate to them for a crack, wear, mechanical damage, and corrosion. If there is a crack, or wear, mechanical damage, or corrosion on the teeth, before further flight, replace with an airworthy part.
(C) With the T/R hub and blade assembly installed, perform a rigging check of the directional control system.
(ii) If the teeth are properly engaged, before further flight, inspect for axial play between both the inboard and outboard T/R hub and blade assemblies.
(A) If there is axial play, remove the T/R hub and blade assembly, and perform the actions required by paragraph (e)(1)(i)(A) through (C) of this AD.
(B) If there is no axial play, inspect for play between the teeth of the curvic coupling and both the inboard and outboard flapping bearing teeth by applying a lead/lag force to the inboard and outboard T/R hub and blade assemblies. If there is play, remove the T/R hub and blade assembly, and perform the actions required by paragraph (e)(1)(i)(A) through (C) of this AD.
(2) Within 10 days after an inspection that resulted in replacing any part as required by paragraph (e)(1) of this AD, email a description of the inspection results that includes a description of each replaced part to: productsupport@bellflight.com. Include the following information in the email subject line: “ASB 429-19-45,” the helicopter's serial number, and the operator's name.
A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a currently valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524.
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.
