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Federal Register / Vol. 86, No. 103 / Tuesday, June 1, 2021 / Rules and Regulations
searching for and locating Docket No.
FAA20210126; 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 final rule, the 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.

a critical location, possibly resulting in reduced control of the helicopter.
Accordingly, EASA AD 20190258
requires a one-time inspection for Tibolt P/N EN3740060022F marked with manufacturer monogram D or with an illegible manufacturer monogram installed on the aft connection of the tail rotor ball bearing control ball bearing control and, depending on findings, contacting AHD for corrective action.
EASA AD 20190258 also prohibits the reinstallation of these Ti-bolts.

Matt Fuller, AD Program Manager, General Aviation & Rotorcraft Unit, Airworthiness Products Section, Operational Safety Branch, FAA, 10101
Hillwood Pkwy., Fort Worth, TX 76177;
telephone 817 2225110; email matthew.fuller@faa.gov.

Comments The FAA received no comments on the NPRM or on the determination of the costs.

FOR FURTHER INFORMATION CONTACT:

SUPPLEMENTARY INFORMATION:

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Background The FAA issued a notice of proposed rulemaking NPRM to amend 14 CFR
part 39 by adding an AD that would apply to Airbus Helicopters Deutschland GmbH AHD Model MBB
BK 117 D2 helicopters with a Ti-bolt part number P/N EN3740060022F
marked with manufacturer monogram D or with an illegible manufacturer monogram, installed on the aft connection of the tail rotor ball bearing control. The NPRM published in the Federal Register on March 3, 2021 86
FR 12294. In the NPRM, the FAA
proposed to require removing any affected Ti-bolt P/N EN3740060022F
from service. The NPRM also to prohibit installing an affected Ti-bolt on the aft connection of the ball bearing control of any helicopter. The NPRM was prompted by EASA AD 20190258, dated October 18, 2019 EASA AD
20190258, issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition for Airbus Helicopters Deutschland GmbH AHD, formerly Eurocopter Deutschland GmbH, Model MBBBK117 D2
helicopters. EASA advises of a report of a broken Ti-bolt. Subsequent investigation revealed that an improper heat treatment process was accomplished on a batch of Ti-bolts, which can lead to hydrogen embrittlement. Hydrogen embrittlement can make high-strength bolts susceptible to stress corrosion, pitting, and failure.
EASA states that this condition, if not detected and corrected, could lead to failure of an affected Ti-bolt installed in
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Discussion of Final Airworthiness Directive
Conclusion 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 about the unsafe condition described in its AD. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these helicopters.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Airbus Helicopters Alert Service Bulletin No. ASB MBB
BK117 D200A001, Revision 1, dated October 16, 2019, which specifies replacing each Ti-bolt P/N EN3740
060022F that is marked with manufacturer monogram D or if the manufacturer monogram cannot be identified with an airworthy Ti-bolt in both locations of the aft connection of ball bearing control and both high frequency HF antenna bracket locations.
This service information 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.
Differences Between This AD and the EASA AD
EASA AD 20190258 applies to Model MBBBK117 D2 helicopters and requires inspecting for Ti-bolt P/N
EN3740060022F marked with manufacturer monogram D or with an illegible manufacturer monogram installed on the aft connection of the ball bearing control. This AD applies to Model MBBBK 117 D2 helicopters with a Ti-bolt P/N EN3740060022F
marked with manufacturer monogram
PO 00000

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D or with an illegible manufacturer monogram installed on the aft connection of the ball bearing control instead. EASA AD 20190258 requires contacting AHD for approved instructions if an affected Ti-bolt is found, whereas this AD requires removing an affected Ti-bolt from service instead.
Costs of Compliance The FAA estimates that this AD
affects 29 helicopters of U.S. Registry.
Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates the following costs to comply with this AD.
Replacing a Ti-bolt takes about 2
work-hours and parts cost about $100
for an estimated cost of $270 per Ti-bolt.
Authority for This Rulemaking Title 49 of the United States Code specifies the FAAs 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 Agencys 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 helicopters identified in this rulemaking action.
Regulatory Findings 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.

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