2021-20-10: Main Rotor Gearbox

The Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive: \n\n2021-20-10 Leonardo S.p.a.: Amendment 39-21748; Docket No. FAA-2021- 0579; Project Identifier MCAI-2020-00267. \n\n(a) Effective Date \n\n\n\tThis airworthiness directive (AD) is effective November 22, 2021. \n\n(b) Affected ADs \n\n\n\tNone. \n\n(c) Applicability \n\n\n\tThis AD applies to Leonardo S.p.a. Model AB139 and AW139 helicopters, certificated in any category, without main gearbox (MGB) spherical bearing lock nut (lock nut) part number (P/N) 3G6320A09152 installed and with: \n\t(1) MGB P/N 3G6320A00131, 3G6320A00132, 3G6320A00133, 3G6320A00134, 3G6320A00135, 3G6320A00136, 3G6320A22031, 4G6320A00132, or 4G6320A00133 installed, or \n\t(2) MGB P/N 3G320A00133 with serial number (S/N) M23, or MGB P/N 3G6320A00134, with S/N M6, N76, N92, P124, P129, P131, P162, P184, Q230, Q243, Q249, R272, V21, V39, V96, V163, V211, V241, V272, V281, V384, V386, or V622 installed, or \n\t(3) MGB P/N 3G6320A00136 with S/N AW1, AW2, AW3, AW5, or AW10 installed. \n\n(d) Subject \n\n\n\tJoint Aircraft Service Component (JASC) Code: 6320, Main Rotor Gearbox. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by a cracked MGB lock nut. The FAA is issuing this AD to replace an affected MGB lock nut with a new MGB lock nut. The unsafe condition, if not addressed, could result in failure of the MGB planetary gears, resulting in loss of control of the helicopter. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Required Actions \n\n\n\t(1) Within 100 hours time-in-service, or during the next scheduled MGB overhaul, whichever occurs first after the effective date of this AD, remove each MGB lock nut P/N 3G6320A09151 from service and replace with MGB lock nut P/N 3G6320A09152 in accordance with Annex A, steps 1 through 17, of Leonardo Helicopters Alert Service Bulletin No. 139-609, Revision A, dated April 13, 2021, except you are not required to send parts to Leonardo Helicopters. \n\tNote to paragraph (g)(1): Leonardo Helicopters service information refers to an MGB lock nut as a ring nut. \n\t(2) As of the effective date of this AD, do not install any MGB having MGB lock nut P/N 3G630A09151 on any helicopter, and do not install any MGB lock nut P/N 3G630A09151 on any helicopter. \n\n(h) Special Flight Permits \n\n\n\tSpecial flight permits are prohibited. \n\n(i) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19,send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (j)(1) of this AD. Information may be emailed to: [email protected]. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. \n\n((Page 57577)) \n\n(j) Related Information \n\n\n\t(1) For more information about this AD, contact Rao Edupuganti, Aerospace Engineer, Dynamic Systems Section, Technical Innovation Policy Branch, Policy & Innovation Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email [email protected]. \n\t(2) The subject of this AD is addressed in European Union Aviation Safety Agency (EASA) AD 2021-0121, dated May 4, 2021. You may view the EASA AD at https://www.regulations.gov in Docket No. FAA-2021-0579. \n\n(k) Material Incorporated by Reference \n\n\n\t(1) The Director of the Federal Register approved the incorporation by reference of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. \n\t(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. \n\t(i) Leonardo Helicopters Alert Service Bulletin No. 139-609, Revision A, dated April 13, 2021. \n\t(ii) (Reserved) \n\t(3) For service information identified in this AD, contact Leonardo S.p.A. Helicopters, Emanuele Bufano, Head of Airworthiness, Viale G. Agusta 520, 21017 C. Costa di Samarate (Va) Italy; telephone +39-0331-225074; fax +39-0331-229046; or at https://customerportal.leonardocompany.com/en-US/. \n\t(4) You may view this service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. \n\t(5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html. \n\n\n\tIssued on September 16, 2021. Lance T. Gant, Director, Compliance & Airworthiness Division, Aircraft Certification Service. (FR Doc. 2021-22468 Filed 10-15-21; 8:45 am) BILLING CODE 4910-13-P