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Rules and Regulations
Federal Register Vol. 86, No. 59
Tuesday, March 30, 2021

AGENCY:

Examining the AD Docket You may examine the AD docket at https www.regulations.gov by searching for and locating Docket No.
FAA20200831; 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, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M30, West Building Ground Floor, Room W12140, 1200 New Jersey Avenue SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT:
Ronald Wissing, Aviation Safety Engineer, Atlanta ACO Branch, FAA, 1701 Columbia Avenue, College Park, GA 30337; phone: 404 4745552; fax:
404 4745606; email: ronald.wissing@
faa.gov.
SUPPLEMENTARY INFORMATION:

The FAA is adopting a new airworthiness directive AD for all Gulfstream Aerospace Corporation Gulfstream Model GV airplanes. This AD was prompted by notification of corrosion present in floor beam support links. This AD requires inspecting the right butt line 6 floor beam inboard support links and bushings for corrosion. The FAA is issuing this AD
to address the unsafe condition on these products.
DATES: This AD is effective May 4, 2021.
The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD
as of May 4, 2021.
ADDRESSES: For service information identified in this final rule, contact Gulfstream Aerospace Corporation, Technical Publications Dept., P.O. Box 2206, Savannah, GA 314022206;
phone: 800 8104853; fax: 912 965
3520; email: pubs@gulfstream.com;
website: https www.gulfstream.com/
en/customer-support/. You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106.
For information on the availability of this material at the FAA, call 816 329
4148. It is also available at https
www.regulations.gov by searching for and locating Docket No. FAA2020
0831.

Background The FAA issued a notice of proposed rulemaking NPRM to amend 14 CFR
part 39 by adding an AD that would apply to all Gulfstream Model GV
airplanes. The NPRM published in the Federal Register on December 10, 2020
85 FR 79443. The NPRM was prompted by notification of a failed floor beam support link at right butt line RBL 6 on a Gulfstream Model GV
airplane, resulting from seizure of the retaining sleeve and bushing at the lower attachment point due to undetected corrosion.
The floor beam support links at RBL
6, fuselage stations FS 499, 531, and 569.5 have a two-piece installation with straight bushings rather than spherical bearings in the inboard link lower end.
Design of the support links allows floor beam movement when the cabin is pressurized. Seizure of the lower bushing will not allow the link assembly to move as designed, resulting in bending stress and potential failure of the link, which may compromise the integrity of the pressure vessel floor.
Gulfstream determined that the procedures for the existing Aircraft Maintenance Manual AMM inspection do not reliably detect corrosion in the floor beam support link lower bushings.
Accordingly, Gulfstream has revised the airworthiness limitation requirements to the AMM by adding a detailed inspection with an initial and repetitive inspections at intervals of 96 months
This section of the FEDERAL REGISTER
contains regulatory documents having general applicability and legal effect, most of which are keyed to and codified in the Code of Federal Regulations, which is published under 50 titles pursuant to 44 U.S.C. 1510.
The Code of Federal Regulations is sold by the Superintendent of Documents.

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration 14 CFR Part 39
Docket No. FAA20200831; Project Identifier 2019CE031AD; Amendment 3921471; AD 20210604
RIN 2120AA64

Airworthiness Directives; Gulfstream Aerospace Corporation Airplanes Federal Aviation Administration FAA, DOT.
ACTION: Final rule.

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and including references for removal and installation instructions for RBL 6
Floor Beam Support Links.
In the NPRM, the FAA proposed to require inspecting the right butt line 6
floor beam inboard support links and bushings for corrosion. The FAA is issuing this AD to prevent link failure, which can compromise the integrity of the pressure vessel floor and lead to loss of pressurization of the airplane.
Discussion of Final Airworthiness Directive Comments The FAA received one comment from Gulfstream. The following presents the comment received on the NPRM and the FAAs response to the comment.
Request for Clarification on Reporting Gulfstream requested the FAA clarify whether the AD requires or recommends reporting the CB 231A inspection results to Gulfstream. Gulfstream noted a discrepancy in the NPRM, where the section titled Proposed AD
Requirements states that the proposed AD recommends sending the inspection results to Gulfstream, but the section titled Differences Between this Proposed AD and the Service Information states that the proposed AD would not require reporting the results of the inspection to Gulfstream.
The FAA agrees. This AD does not require reporting the results of the inspection. This AD is not an interim action; mandating a report of the inspection results is not necessary to correct the unsafe condition. The FAA
should not have included conflicting language in the NPRM to this effect. The FAA has revised the preamble of this final rule to correct this discrepancy.
Conclusion The FAA reviewed the relevant data, considered any comments received, 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 products. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Gulfstream GV
Customer Bulletin Number 231,
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