Airworthiness Directive · Amendment 39-22298 · Tail rotor head
Airbus Helicopters
This AD applies to all Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters. This AD was prompted by an occurrence reported where during an inspection of a tail rotor head (TRH) pitch change spider, excessive play and excessive wear were detected, due to an unwanted rotating motion. This AD requires for helicopters with certain part- numbered TRH spider pitch change units installed, inspecting for correct installation of the spider pitch change nut (nut); marking a 2 to 5 mm wide black paint index mark and repetitively inspecting the alignment of the marking; and additional inspections and corrective actions if necessary. This AD also allows an affected part to be installed on a helicopter if certain requirements of this AD are met. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For helicopters with TRH spider pitch change unit, part number (P/N) 350A33-2030-00, 350A33-2167-00, or 350A33-2167-01 installed, within 50 hours time-in-service (TIS) after the effective date of this AD:
(i) Inspect the nut for correct installation. If the nut is missing or loose, before further flight, remove the bearing from the TRH spider pitch change unit and do the following:
(A) Inspect the TRH spider pitch change unit for corrosion. If there is any corrosion, before further flight, remove the affected part from service and replace with an airworthy part.
(B) Inspect for rotation and wear on the faces of the bushes. For the purposes of this AD, indications of rotation and wear include tearing, peening, metal pick-up, and hammering. If there is any rotation or any wear on the faces of the bushes, before further flight, remove the bushes from service and replace with airworthy bushes.
(C) Using a 5X or higher power magnifying glass visually inspect the rotating plate and the rotating plate threads for damage. For the purposes of this AD, indications of damage include wear, deformation, stripping, galling, and corrosion. If there is any damage on the rotating plate or the rotating plate threads, before further flight, remove the rotating plate from service and replace with an airworthy rotating plate.
Note 1 to paragraph (g)(1)(i): Airbus Helicopters Mechanical Repair Manual (MRM) AS350 65-20-00-713, dated March 29, 2017, also known as Work Card 65-20-00-713 MRM, and Airbus Aircraft Maintenance Manual (AMM) AS350 65-21-00, 4-9b, dated May 16, 2019, also known as Task 65-21-00, 4-9 AMM, specify disassembly and reassembly information for the TRH pitch change unit.
(ii) Identify the position of the TRH pitch change unit (item a) and of bearing spacer (item b) by marking a 2 to 5 mm wide black paint index mark (item C) with black paint as depicted in Figure 1 of Airbus Helicopters Alert Service Bulletin (ASB) No. AS350-05.01.03, Revision 0, dated December 16, 2021 (ASB AS350-05.01.03), or Airbus Helicopters ASB No. AS355-05.00.86, Revision 0, dated December 16, 2021 (ASB AS355-05.00.86), as applicable to your model helicopter.
(iii) Within 10 hours TIS after the initial marking required by paragraph (g)(1)(ii) of this AD, and thereafter at intervals not to exceed 10 hours TIS, visually inspect the alignment of the marking. An example of a properly aligned marking is depicted in Figure 1 of ASB AS350-05.01.03 and ASB AS355-05.00.86, as applicable to your model helicopter. If the black paint index mark (item C) is misaligned, before further flight, inspect the TRH spider pitch change unit by accomplishing the actions required by paragraphs (g)(1)(i) and (ii) of this AD.
(2) As of the effective date of this AD, do not install TRH spider pitch change unit P/N 350A33-2030-00, 350A33-2167-00, or 350A33-2167-01 on any helicopter, unless you do the actions required by paragraphs (g)(1)(i) and (ii) of this AD before further flight after installation, and thereafter do the actions required by paragraph (g)(1)(iii) of this AD at the times specified in paragraph (g)(1)(iii) 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.
