Airworthiness Directive · Amendment 39-21866 · Tail rotor system
Airbus Helicopters
Superseded. A later AD replaced this one: AD 2025-20-10. Comply with the one in force.
This AD applies to Airbus Helicopters Model EC120B helicopters, certificated in any category, all serial numbers.
The FAA is superseding Airworthiness Directive (AD) 2020-11- 05, which applied to all Airbus Helicopters Model EC120B helicopters. AD 2020-11-05 required repetitive inspections of the tail rotor (TR) hub body for cracks and applicable corrective actions if necessary, and repetitive replacement of the attachment bolts, washers, and nuts of the TR hub body. This AD was prompted by a report of recurrent loss of tightening torque on several attachment bolts on the TR hub body. This AD retains certain requirements of AD 2020-11-05, adds repetitive inspections, requires additional corrective actions, and updates applicable service information. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within 15 hours time-in-service (TIS) or 7 days, whichever occurs first after the effective date of this AD, and thereafter at intervals not to exceed 15 hours TIS, using a light source and mirror, visually inspect TR hub body part number (P/N) C642A0100103 for a crack in the entire inspection area depicted in Figure 1 of Airbus Helicopters Emergency Alert Service Bulletin 05A020 Revision 2, dated February 8, 2021. If there is a crack, before further flight, perform the actions in paragraphs (g)(1)(i) and (ii) of this AD.
(i) Remove the TR hub body and each bolt, washer, and nut installed on the TR hub body from service and replace with airworthy parts.
(ii) Inspect the TR splined flange for corrosion, impacts, fretting, wear, and a crack in the areas identified in Figure 2 to paragraph (g)(1)(ii) of this AD. If the condition of the part (including corrosion, impacts, fretting, wear, or cracks) exceeds the criteria as specified in Figure 1 to paragraph (g)(1)(ii) of this AD, before further flight, remove the splined flange from service and replace with an airworthy part.
Note 1 to paragraph (g)(1)(ii): You may refer to “Detailed Check—Splined Flange,” Task 64-21-00, 6-5, Airbus Aircraft Maintenance Manual (AMM), dated October 15, 2020, which pertains to the TR splined flange inspection.
(2) For helicopters with 9,000 or more total hours TIS, or with unknown total hours TIS, within 15 hours TIS or 7 days, whichever occurs first after the effective date of this AD, and thereafter at intervals not to exceed 1,000 hours TIS, remove each bolt, washer, and nut installed on the TR hub body from service and replace with airworthy parts and perform the actions in paragraph (g)(1)(ii) of this AD.
(3) For helicopters with less than 9,000 total hours TIS, within 1,000 hours TIS or before accumulating 9,000 total hours TIS, whichever occurs first after the effective date of this AD, and thereafter at intervals not to exceed 1,000 hours TIS, remove each bolt, washer, and nut installed on the TR hub body from service and replace with airworthy parts and perform the actions in paragraph (g)(1)(ii) of this AD.
(4) As of the effective date of this AD, do not install TR hub body P/N C642A0100103 on any helicopter, unless the actions of paragraph (g)(1) of this AD have been accomplished.
