AD 2021-02-03 Airworthiness Directives; Leonardo S.p.a. Helicopters

This AD becomes effective April 1, 2021.

(1) Actions accomplished before the effective date of this AD in accordance with the Compliance Instructions, Part II, of Finmeccanica Bollettino Tecnico No. 189-069, dated February 12, 2016 (BT 189-069), are considered acceptable for compliance with the corresponding actions in paragraph (e)(7)(i) of this AD. (2) Actions accomplished before the effective date of this AD in accordance with the Compliance Instructions, Part III, of BT 189-069, are considered acceptable for compliance with the corresponding actions in paragraph (e)(7)(ii) of this AD.

(1) The Manager, Rotorcraft Standards Branch, FAA, may approve AMOCs for this AD. Send your proposal to: Matt Fuller, AD Program Manager, Operational Safety Branch, Airworthiness Products Section, General Aviation & Rotorcraft Unit, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-5110; email 9-ASW-FTW-AMOC-Requests@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, the FAA suggests 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.

(1) Within 10 hours time-in-service (TIS), reduce the torque of the nut on the bolt attaching each MR damper to the MR hub by following paragraphs 4 through 7 of the Accomplishment Instructions, Part I, of Leonardo Helicopters Alert Service Bulletin No. 189-102, Revision A, dated December 21, 2017 (ASB 189-102). (2) Within 30 hours TIS or before the MR damper body end (body end) accumulates 500 hours TIS, whichever occurs later, and thereafter at intervals not to exceed 500 hours TIS, replace the MR damper. (3) Within 30 hours TIS, before the MR damper accumulates 300 hours TIS, or within 300 hours TIS since the last overhaul, whichever occurs later, dye penetrant inspect using a 5X power magnifying glass or eddy current inspect each MR damper rod end (rod end) and body end for a crack in the areas depicted in Figure 2 of Finmeccanica Bollettino Tecnico No. 189-080, Revision A, dated July 15, 2016 (BT 189-080). (i) If there is a crack on the body end, before further flight, replace the MR damper. (ii) If there is a crack on the rod end, before further flight, replace the rod end and, within 300 hours TIS, dye penetrant or eddy current inspect the rod end for a crack as described in paragraph (e)(3) of this AD. (iii) If there are no cracks, before further flight, mark the rod end and body end with a dot of black polyurethane paint as shown in Figure 13 of BT 189-080. (iv) Thereafter, before the first flight of each day, using a mirror and a magnifying glass visually inspect each rod end and body end for a crack in the areas shown in Figure 14 of BT 189-080. If there is a crack in the rod end, before further flight, replace the rod end. If there is a crack on the body end, before further flight, replace the MR damper. (4) Within the compliance times listed in paragraphs (e)(4)(i) and (ii) of this AD, inspect each rod end bearing and body end for bearing rotation in the damper seat. An example of rotation (misaligned slippage marks) is shown in Figure 4 of BT 189-080. If there is any bearing rotation in the rod end, before further flight, replace the rod end. If there is any bearing rotation in the body end, before further flight, replace the MR damper. (i) For MR dampers that have accumulated less than 300 hours TIS since new or since the last overhaul, within 30 hours TIS and thereafter at intervals not to exceed 10 hours TIS. (ii) For MR dampers that have accumulated 300 or more hours TIS since new or since the last overhaul, within 5 hours TIS and thereafter before the first flight of each day. (5) For helicopters with an MR damper with a serial number (S/N) MCR0001 through MCR0154 and MCR0174 through MCR0195, within 30 hours TIS and thereafter at intervals not to exceed 20 hours TIS until the MR damper has accumulated 600 hours TIS, visually inspect each MR damper broached ring nut for broken teeth, proper engagement, and alignment as depicted in Figure 5 and shown in Figures 6, 7, and 8 of BT 189-080. If there is a broken tooth, improper engagement, or misalignment of the broached ring nut, before further flight, remove from service the rod end and broached ring nut. (6) Within 50 hours TIS and thereafter at intervals not to exceed 100 hours TIS: (i) Rotate the body end around the damper axis to put it near the middle position and determine the bearing friction torque value of the body end, using as a reference Figure 11 of BT 189-080. Note 1 to Paragraph (e)(6)(i): Applying too much force while rotating the body end around the damper axis may cause damage. (A) If the torque value of the body end is more than 30.0 Nm (265.5 in lb), before further flight, replace the MR damper. (B) If the torque value of the body end is 30.0 Nm (265.5 in lb) or less, determine the bearing friction torque value of each rod end, using as a reference Figure 11 of BT 189-080. If the torque value of the rod end is more than 30.0 Nm (265.5 in lb), before further flight, replace the rod end. (ii) Inspect each MR damper anti-rotation block for wear

This AD defines the unsafe condition as a crack in an MR damper, which if not detected and corrected, could lead to loss of the lead-lag damping function of the MR blade, resulting in damage of the MR damper, detachment of the MR damper in-flight, and subsequent loss of control of the helicopter.