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Federal Register / Vol. 86, No. 36 / Thursday, February 25, 2021 / Rules and Regulations main rotor MR damper. This AD was prompted by reports of in-service MR
damper failures and the development of an improved MR damper. This condition, if not corrected, could lead to loss of the lead-lag damping function of the MR blade, possibly resulting in damage to adjacent critical rotor components and subsequent loss control of the helicopter. The actions of this AD
are intended to address the unsafe condition on these products.
This AD is effective April 1, 2021.
The Director of the Federal Register approved the incorporation by reference of certain documents listed in this AD
as of April 1, 2021.

DATES:

For service information identified in this final rule contact Leonardo S.p.A. Helicopters, Emanuele Bufano, Head of Airworthiness, Viale G.Agusta 520, 21017 C.Costa di Samarate Va Italy; telephone +39
0331225074; fax +390331229046; or at https www.leonardocompany.com/
en/home. You may view the referenced service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N321, Fort Worth, TX 76177. It is also available on the internet at https
www.regulations.gov by searching for and locating Docket No. FAA2020
0503.

ADDRESSES:

Examining the AD Docket You may examine the AD docket on the internet at https
www.regulations.gov by searching for and locating Docket No. FAA2020
0503; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
The AD docket contains this AD, the European Aviation Safety Agency now European Union Aviation Safety Agency EASA AD, any service information that is incorporated by reference, any comments received, and other information. The street address for Docket Operations is U.S. Department of Transportation, Docket Operations, M
30, West Building Ground Floor, Room W12140, 1200 New Jersey Avenue SE, Washington, DC 20590.
Matt Fuller, AD Program Manager, Operational Safety Branch, Airworthiness Products Section, General Aviation & Rotorcraft Unit, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817222
5110; email matthew.fuller@faa.gov.

FOR FURTHER INFORMATION CONTACT:

SUPPLEMENTARY INFORMATION:

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Discussion The FAA issued a notice of proposed rulemaking NPRM to amend 14 CFR
part 39 by adding an AD that would apply to Leonardo Model AW189
helicopters with MR damper part number P/N 4F6220V00251 installed.
The NPRM published in the Federal Register on May 20, 2020 85 FR 30664.
The NPRM proposed to require reducing the installation torque of the nuts on the bolts attaching the MR damper to the MR hub. The NPRM also proposed to require, at specified intervals, replacing the affected MR damper; dye penetrant or eddy current inspecting the rod end and body end of each MR damper for a crack, visually inspecting the rod end and body end of each MR damper for a crack, and replacing any cracked MR
damper. For certain helicopters, the NPRM also proposed to require inspecting each rod end and body end bearing for rotation, and replacing the rod end or MR damper as applicable if there is any rotation; inspecting the lag damper broached ring nut for damage, correct engagement, and alignment and removing the rod end and broached ring nut from service if any of those conditions exist. For all helicopters, the NPRM proposed to require, at specified intervals, inspecting the bearing friction torque of each MR damper body end and rod end, and replacing the MR
damper if the torque value exceeds 30.0
Nm 265.5 lb in; inspecting the MR
damper anti-rotation block for wear and replacing the anti-rotation block if there is wear beyond acceptable limits; and replacing each special washer P/N
3G6220A05051 with special washer P/N
3G6220A05052. For certain MR
dampers, the NPRM proposed to require inspecting the broached ring for damage and alignment, removing the broached ring from service if there is damage, and replacing the broached ring if the rod end and broached ring cannot be aligned. Finally, the NPRM proposed to require inspecting certain serialnumbered MR dampers for correct torque of the broached ring prior to installation on any helicopter. The proposed requirements were intended to detect 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.
The NRPM was prompted by EASA
AD No. 20160145R1, dated January 17, 2018 EASA AD 20160145R1, issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition
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for Leonardo Model AW189 helicopters with MR damper P/N 4F6220V00251
installed. EASA advises that a MR
damper failed, which resulted in complete seizure of the body end lug and an in-flight disconnection of the damper. EASA states that a combination of factors may have contributed to the MR damper disconnection, and that this condition could result in loss of the lead-lag damping function of the MR
blade, damage to adjacent critical rotor components, and subsequent reduced control of the helicopter. The contributing factors include cracks, slippage marks, damaged broach ring teeth, and loss of torque.
According to EASA, the AW189 MR
damper is a similar design to the MR
dampers installed on Model AW139
helicopters, where multiple MR damper failures have been reported involving the body end lug, the eye end lug, and the rod end. To correct this condition, EASA issued a series of superseded and revised ADs to require repetitive inspections of certain MR dampers, and similar corrective actions as those for Model AW139 helicopters. EASA AD
20160145R1 requires various one-time and repetitive inspections of the MR
damper, a torque check of the body end, and replacing any MR damper with a crack or that fails the torque check.
EASA AD 20160145R1 also allows installation of a new MR damper, P/N
8G6220V00151, as an optional terminating action for the repetitive inspections.
Comments The FAA gave the public the opportunity to participate in developing this final rule, but the FAA did not receive any comments on the NPRM or on the determination of the cost to the public.
FAAs Determination These helicopters have been approved by EASA and are approved for operation in the United States. Pursuant to the FAAs bilateral agreement with the European Union, EASA has notified the FAA of the unsafe condition described in its AD. The FAA is issuing this AD
after evaluating all of the information provided by EASA and determining the unsafe condition exists and is likely to exist or develop on other helicopters of the same type design and that air safety and the public interest require adopting these AD requirements as proposed.
Differences Between This AD and the EASA AD
The EASA AD requires contacting the manufacturer under certain conditions, while this AD does not.

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