AD 2021-05-05

This AD is effective April 16, 2021.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of April 16, 2021.

For material incorporated by reference (IBR) in this AD, contact the EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu; internet www.easa.europa.eu. You may find this material on the EASA website at https://ad.easa.europa.eu. You may view this material 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. It is also available in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-1123.

Kathleen Arrigotti, Aviation Safety Engineer, Large Aircraft Section, International Validation Branch, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone and fax 206-231-3218; email kathleen.arrigotti@faa.gov.

The EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2017-0125, dated July 21, 2017 (EASA AD 2017-0125) (also referred to as the Mandatory Continuing Airworthiness Information, or the MCAI), to correct an unsafe condition for all Airbus Helicopters Model SA 365 N1, AS 365 N2, AS 365 N3, SA 366 G1, EC 155 B, and EC 155 B1 helicopters. EASA AD 2017-0125 supersedes EASA AD 2017-0007, dated January 13, 2017, which superseded EASA AD 2016-0097R1, dated May 25, 2016 (which corresponds to FAA AD 2016-23-05). EASA AD 2017-0125 adds helicopters to the applicability, adds repetitive inspections of the magnetic plug after bearing replacement, requires the use of the revised Airbus Helicopters Alert Service Bulletin (ASB) instructions, and requires replacement of the TGB with a modified unit, which terminates the repetitive inspections.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2016-23-05, Amendment 39-18712 (81 FR 85126, November 25, 2016) (AD 2016-23-05). AD 2016-23-05 applied to certain Airbus Helicopters Model SA-365N1, AS-365N2, AS 365 N3, SA-366G1, EC 155B, and EC155B1 helicopters. The NPRM published in the Federal Register on December 14, 2020 (85 FR 80689). The NPRM was prompted by a determination that additional inspections, replacements, and modifications are necessary to address the unsafe condition. The NPRM proposed to retain the requirements of AD 2016-23-05 and also require modifying the helicopter by replacing the TGB control shaft guide bushes; repetitive inspections of the TGB magnetic plug and corrective actions if necessary; repetitive replacements of the bearing; and modifying the helicopter by replacing the TGB; as specified in an EASA AD. The NPRM also proposed to add helicopters to the applicability.

The FAA is issuing this AD to address damage to the bearing, which could result in end play, loss of tail rotor pitch control, and subsequent loss of control of the helicopter. See the MCAI for additional background information.

The FAA gave the public the opportunity to participate in developing this final rule. The FAA received no comments on the NPRM or on the determination of the cost to the public.

The FAA has updated the costs for the new required actions and on-condition actions based on data received since the NPRM was issued.

The FAA reviewed the relevant data and determined that air safety and the public interest require adopting this final rule as proposed, except for minor editorial changes. The FAA has determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM.

EASA AD 2017-0125 describes procedures for modifying the helicopter by replacing TGB control shaft guide bushes, repetitive inspections (checks) of the oil level of the tail rotor gearbox and, if necessary, filling the oil to the maximum level, repetitive inspections of the TGB magnetic plug for the presence of particles and corrective actions if necessary (corrective actions include removing the TGB, complying with certain work cards to address particles and other conditions such as abrasions, scales, flakes, and splinters, and replacing the bearing), repetitive replacements of the bearing; and modifying the helicopter by replacing the TGB.

This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Although this AD does not explicitly restate the requirements of AD 2016-23-05, this AD retains certain requirements of AD 2016-23-05. Those requirements are referenced in paragraphs (2) and (5) of EASA AD 2017-0125, which, in turn, is referenced in paragraph (g) of this AD.

The FAA estimates that this AD affects 52 helicopters of U.S. registry. The FAA estimates the following costs to comply with this AD:

According to the manufacturer, some or all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators. The FAA does not control warranty coverage for affected operators. As a result, the FAA has included all known costs in this cost estimate.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2016-23-05, Amendment 39-18712 (81 FR 85126, November 25, 2016), and adding the following new AD: