DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0831; Project Identifier 2019-CE-031-AD]
RIN 2120-AA64

Airworthiness Directives; Gulfstream Aerospace Corporation Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for all Gulfstream Aerospace Corporation (Gulfstream) Model GV
airplanes. This proposed AD was prompted by notification of corrosion
present in floor beam support links. This proposed AD would require in-
specting the right butt line 6 floor beam inboard support links and bush-
ings for corrosion. The FAA is proposing this AD to address the unsafe
condition on these products.

DATES: The FAA must receive comments on this proposed AD by January 25,
2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the
instructions for submitting comments.

Fax: 202-493-2251.

Mail: U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC 20590.

Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Gulfstream
Aerospace Corporation, Technical Publications Dept., P.O Box 2206,
Savannah, GA 31402-2206; phone: (800) 810-4853; fax: (912) 965-3520;
email: pubs@gulfstream.com; internet: https://www.gulfstream.com/en/
customer-support/. You may view this referenced service information at
the FAA, Airworthiness Products Section, Operational Safety Branch, 901
Locust, Kansas City, Missouri 64106. For information on the
availability of this material at the FAA, call (816) 329-4148.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-0831; 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 NPRM, any comments
received, and other information. The street address for Docket
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Ronald "Ron" Wissing, Aviation
Safety Engineer, Atlanta ACO Branch, FAA, 1701 Columbia Avenue, College
Park, Georgia 30337; phone: (404) 474-5552; fax: (404) 474-5606; email:
ronald.wissing@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2020-0831;
Project Identifier 2019-CE-031-AD" at the beginning of your comments.
The most helpful comments reference a specific portion of the proposal,
explain the reason for any recommended change, and include supporting
data. The FAA will consider all comments received by the closing date
and may amend this proposal because of those comments.

Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this NPRM.

Confidential Business Information

CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as "PROPIN." The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to
Ronald "Ron" Wissing, Aviation Safety Engineer, Atlanta ACO Branch,
FAA, 1701 Columbia Avenue, College Park, Georgia 30337. Any commentary
that the FAA receives which is not specifically designated as CBI will
be placed in the public docket for this rulemaking.

Background

The FAA was advised of a failed floor beam support link at right
butt line (RBL) 6 on a Gulfstream Model GV airplane. The failed support
link resulted 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 does 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 and including references for removal and
installation instructions for RBL 6 Floor Beam Support Links.

This condition, if not addressed, could result in link failure,
which can compromise the integrity of the pressure vessel floor and
lead to loss of pressurization to the airplane.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Gulfstream GV Customer Bulletin Number 231,
Revision A, dated July 30, 2019 (Gulfstream CB 231A). The service
information contains procedures for the inspection of the RBL 6, FS
499, 531, and 569.5, and the bushing in the lower end of the link and
all attachments for corrosion.

The FAA reviewed Gulfstream GV AMM, Section 05-10-10, Revision 51,
dated February 28, 2020. The service information identifies tasks for a
recurring detailed inspection of the floor beam and wing links FS 465
through FS 576.

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.

FAA's Determination

The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop in other
products of the same type design.

Proposed AD Requirements

This proposed AD would require a one-time inspection of the RBL 6
floor beam inboard support links and bushings for corrosion along with
any repairs necessary. This proposed AD would require a recurring
inspection of the floor beam support links. This proposed AD also
recommends sending the inspection results to Gulfstream.

Differences Between This Proposed AD and the Service Information

Gulfstream CB 231A requires reporting the results of the inspection
to Gulfstream and this proposed AD would not.

Costs of Compliance

The FAA estimates that this proposed AD would affect 148 airplanes
of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs

The FAA estimates the following costs to do any necessary
replacements that would be required based on the results of the
proposed inspection. The FAA has no way of determining the number of
airplanes that might need these replacements:

On-condition Costs

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

Authority for This Rulemaking

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.

Regulatory Findings

The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 this proposed
regulation:

(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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

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

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive: