Voglio sapere a riguardo di…

Federal Register / Vol. 86, No. 120 / Friday, June 25, 2021 / Rules and Regulations Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the EASA AD, any comments received, and other information. The street address for Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT:
Darren Gassetto, Aerospace Engineer, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 1600
Stewart Ave., Suite 410, Westbury, NY
11590; telephone 516 2287323; email Darren.Gassetto@faa.gov.
SUPPLEMENTARY INFORMATION:

lotter on DSK11XQN23PROD with RULES1

Background The EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD
20200271, dated December 8, 2020
EASA AD 20200271 also referred to as the Mandatory Continuing Airworthiness Information, or the MCAI, to correct an unsafe condition for Leonardo S.p.A. formerly Finmeccanica S.p.A, AgustaWestland S.p.A., Agusta S.p.A.; and AgustaWestland Philadelphia Corporation, formerly Agusta Aerospace Corporation Model AB139, AW139, and AW189 helicopters, all serial numbers. Although EASA AD 2020
0271 applies to Model AB139, AW139, and AW189 helicopters, all serial numbers, this AD applies to helicopters with an affected part installed instead.
This AD was prompted by a report of the in-flight failure of one of the three stainless steel external rings bonded to the main rotor swashplate boot installed on Model AB139 and AW139
helicopters. The broken ring, under the effects of the centrifugal force, was released from the main rotor swashplate boot and impacted one tail rotor blade, causing extensive damage. Investigation revealed that the failure of the external ring was caused by fatigue initiated by corrosion. A contributing factor to the external ring failure was disbonding at the four points where the affected ring was bonded to the main rotor swashplate boot. Leonardo S.p.a. Model AW189 helicopters have a similar design, therefore, this model may be subject to the same unsafe condition revealed on the Model AB139 and AW139 helicopters. Since EASA AD
20200271 was published, there have been two more reports of discrepant main rotor boots.
The FAA is issuing this AD to address corrosion, cracking, and damage to the adhesive e.g., disbonding of any stainless steel external ring bonded to the main rotor swashplate boot, which
VerDate Sep<11>2014

16:27 Jun 24, 2021

Jkt 253001

could result in release of a ring from the main rotor swashplate boot, resulting in damage to, and reduced control of, the helicopter. See the EASA AD for additional background information.
Related IBR Material Under 1 CFR Part 51
EASA AD 20200271 specifies procedures for repetitive detailed inspections DET of the affected external rings for corrosion including superficial oxidation, and cracks, and, depending on findings, polishing corrosion, and replacing an affected external ring with a serviceable part.
EASA AD 20200271 also requires repetitive inspections for damage of the adhesive e.g., disbonding between the bonding areas of the affected external rings and the main rotor swashplate boot and re-applying the adhesive if necessary. For certain helicopters, EASA AD 20200271 requires a onetime restoring of the adhesive between the bonding areas of the affected external rings and the main rotor swashplate boot. For all helicopters, EASA AD 20200271 allows, under certain conditions, reinstallation of an affected part on a helicopter.
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.
FAAs Determination These products have been approved by the aviation authority of another country, and are approved for operation in the United States. Pursuant to the FAAs bilateral agreement with the State of Design Authority, the FAA has been notified of the unsafe condition described in the MCAI referenced above. The FAA is issuing this AD after evaluating all pertinent information and determining that the unsafe condition exists and is likely to exist or develop on other products of these same type designs.
Requirements of This AD
This AD requires accomplishing the actions specified in EASA AD 2020
0271, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this AD.
Explanation of Required Compliance Information In the FAAs ongoing efforts to improve the efficiency of the AD
process, the FAA initially worked with Airbus and EASA to develop a process to use certain EASA ADs as the primary source of information for compliance
PO 00000

Frm 00021

Fmt 4700

Sfmt 4700

33499

with requirements for corresponding FAA ADs. The FAA has since coordinated with other manufacturers and civil aviation authorities CAAs to use this process. As a result, EASA AD
20200271 is incorporated by reference in the FAA final rule. This AD would, therefore, require compliance with EASA AD 20200271 in its entirety, through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. Using common terms that are the same as the heading of a particular section in the EASA AD does not mean that operators need comply only with that section. For example, where the AD requirement refers to all required actions and compliance times, compliance with this AD requirement is not limited to the section titled Required Actions and Compliance Times in the EASA
AD. Service information specified in EASA AD 20200271 that is required for compliance with EASA AD 20200271
is available on the internet at https
www.regulations.gov by searching for and locating Docket No. FAA2021
0512.
FAAs Justification and Determination of the Effective Date Section 553b3B of the Administrative Procedure Act 5 U.S.C.
551 et seq. authorizes agencies to dispense with notice and comment procedures for rules when the agency, for good cause finds that those procedures are impracticable, unnecessary, or contrary to the public interest. Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance.
Further, section 553d of the APA
authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption.
The FAA has found that the risk to the flying public justifies foregoing notice and comment prior to adoption of this rule because the in-flight failure of a stainless steel external ring bonded to the main rotor swashplate boot could result in damage to, and reduced control of, the helicopter. In addition, the compliance time for the required action is shorter than the time necessary for the public to comment and for publication of the final rule. Based on the average utilization rate for the affected Model AB139 and AW139 helicopters, it would take approximately one month for an affected helicopter to reach 25 hours time-in-service. Therefore, notice and
E:FRFM25JNR1.SGM

25JNR1