[Federal Register Volume 86, Number 212 (Friday, November 5, 2021)]
[Proposed Rules]
[Pages 61088-61090]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-24082]



[[Page 61088]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0958; Project Identifier 2019-CE-010-AD]
RIN 2120-AA64


Airworthiness Directives; Gulfstream Aerospace Corporation 
Airplanes

AGENCY: Federal Aviation Administration (FAA), 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 and GV-
SP airplanes. This proposed AD results from corrosion of the horizontal 
stabilizer lower bonded skin assemblies. This proposed AD would require 
inspecting the horizontal stabilizer lower skin and associated bonded 
doublers and bonded stringers, repairing the area susceptible to 
corrosion, and incorporating revisions to the airworthiness limitations 
section (ALS) in the existing aircraft maintenance manual (AMM). 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 December 
20, 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; phone: (800) 810-4853; fax: (912) 965-3520; email: 
[email protected]; 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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0958; 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 Wissing, Aviation Safety 
Engineer, Atlanta ACO Branch, FAA, 1701 Columbia Avenue, College Park, 
GA 30337; phone: (404) 474-5552; fax: (404) 474-5606; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0958; Project Identifier 
2019-CE-010-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 Wissing, Aviation Safety Engineer, Atlanta ACO Branch, FAA, 1701 
Columbia Avenue, College Park, GA 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

    Gulfstream notified the FAA of bond line corrosion on Model GV and 
GV-SP airplanes, which causes disbonding between the horizontal 
stabilizer lower skin and associated bonded doublers and bonded 
stringers. Gulfstream determined that the existing visual inspection in 
the AMM does not reliably detect bond line corrosion, and they added a 
repetitive non-destructive testing (NDT) inspection to detect the 
damage. Gulfstream added the revised inspections to the ALS of the AMM. 
This condition, if not addressed, could compromise the structural 
integrity of the horizontal stabilizer and lead to loss of control of 
the airplane.

FAA's Determination

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

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Gulfstream G500-5000 Customer Bulletin No. 190, 
Revision B; Gulfstream G550 Customer Bulletin No. 190, Revision B; and 
Gulfstream GV Customer Bulletin No. 228, Revision B; all dated October 
31, 2019. For the applicable marketing designation specified on each 
document, the customer bulletins specify procedures for inspecting the 
horizontal stabilizer lower bonded skin.
    The FAA also reviewed Gulfstream V Maintenance Manual, 
Airworthiness Limitations, Section 05-10-10, dated February 28, 2020; 
Gulfstream G500-5000 Maintenance Manual, Airworthiness Limitations, 
Section 05-10-10, dated March 15, 2021; and Gulfstream G550 Maintenance 
Manual, Airworthiness Limitations, Section 05-10-10, dated March 15, 
2021. For the applicable marketing designation specified on each 
document, the service information contains inspection intervals for 
nondestructive testing of the lower horizontal stabilizer skins and 
provides the specific reference for the inspection procedures.

[[Page 61089]]

    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 ADDRESSES.

Other Related Service Information

    The FAA also reviewed the following service documents related to 
this NPRM:
     Gulfstream Service Letter Document No. GSL505510019, 
Revision E, dated September 3, 2021, which contains procedures for 
applying on-wing corrosion inhibiting compound to the horizontal 
stabilizer.
     Gulfstream Service Letter Document No. GSL505510020, 
Revision C, dated March 12, 2020, which contains procedures for 
applying corrosion inhibiting compound to the horizontal stabilizer.
     Gulfstream V Nondestructive Testing Procedures Manual 
Chapter 05-00-00, 1. Horizontal Stabilizer Lower Skin Resonance C-
Scan--NDT Procedure.

Proposed AD Requirements in This NPRM

    This proposed AD would require inspecting the horizontal stabilizer 
lower skin and associated bonded doublers and bonded stringers, 
repairing the area susceptible to corrosion, and incorporating 
revisions to the ALS of the existing AMM.

Differences Between This Proposed AD and the Service Information

    The differences between Gulfstream G500-5000 Customer Bulletin No. 
190, Revision B; Gulfstream G550 Customer Bulletin No. 190, Revision B; 
and Gulfstream V Customer Bulletin No. 228, Revision B; all dated 
October 31, 2019, and this proposed AD are listed below.
     The service bulletins exclude certain serial-numbered 
airplanes inspected by Gulfstream, but this proposed AD would apply to 
all Model GV and GV-SP airplanes.
     The service bulletins include an optional horizontal 
stabilizer lower skin resonance A-Scan NDT inspection (referred to in 
the Customer Bulletin as ``Part I Inspection'') for critical areas of 
the horizontal stabilizer bonded lower skin assemblies, but this 
proposed AD would not require the Part I Inspection.
     The service bulletins allow the horizontal stabilizer 
lower skin resonance C-Scan NDT inspection (referred to in the Customer 
Bulletin as a ``Part II Inspection'') and application of corrosion 
inhibiting compound to be repeated indefinitely every 48 months. This 
proposed AD would only allow the Part II inspection to be performed one 
time and, within 48 months after the inspection, would require approved 
repairs.
     The customer bulletins contain actions labeled ``Required 
for Compliance'' (RC), and the language in the customer bulletin and in 
paragraph (j)(4) of this proposed AD indicate that operators must 
comply with all actions labeled RC for compliance with this AD. 
However, this AD does not require all of the steps in the customer 
bulletins that are labeled as RC. Operators only need to comply with 
the RC steps required by paragraph (i) of this AD.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect up to 694 airplanes of U.S. registry. The FAA estimates the 
following costs to comply with this proposed AD:

                                                 Estimated Costs
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                                                                                 Cost per        Cost on U.S.
             Action                  Labor cost             Parts cost            product          operators
----------------------------------------------------------------------------------------------------------------
Resonance C-Scan NDT (Part II)   80 work-hours x     Not applicable.........          $6,800  $2,196,400 (for
 inspection and CIC application.  $85 per hour =                                               323 airplanes).
                                  $6,800.
AMM revision...................  1 work-hour x $85   Not applicable.........              85  $58,990 (for 694
                                  per hour = $85.                                              airplanes).
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    The extent of corrosion found during the proposed inspection may 
vary significantly from airplane to airplane. The FAA has no way of 
determining the number of airplanes that might need repair or the cost 
to repair each airplane.

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) Would not affect intrastate aviation in Alaska, and
    (3) Would 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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:


[[Page 61090]]


Gulfstream Aerospace Corporation: Docket No. FAA-2021-0958; Project 
Identifier 2019-CE-010-AD.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by December 20, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Gulfstream Aerospace Corporation Model GV and 
GV-SP airplanes, all serial numbers, certificated in any category.
    Note 1 to paragraph (c): Model GV-SP airplanes are also referred 
to by the marketing designations G500, G550, and G500-5000.

 (d) Subject

    Joint Aircraft System Component (JASC) Code 5510, Horizontal 
Stabilizer Structure.

(e) Unsafe Condition

    This AD results from corrosion of the horizontal stabilizer 
lower bonded skin assemblies. The FAA is issuing this AD to detect 
and correct bond line corrosion, which if not addressed, could 
result in compromise of the structural integrity of the horizontal 
stabilizer and lead to loss of control of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Incorporation of Airworthiness Limitations (ALS) Revisions

    Within 30 days after the effective date of this AD, incorporate 
into your existing maintenance or inspection program the ALS 
revision specified in paragraph (g)(1), (2), or (3) of this AD for 
your applicable airplane designation.
    (1) For Model GV airplanes: Section F and Table 12: Horizontal 
Stabilizer Inspection Table in section 05-10-10, Airworthiness 
Limitations, of the Gulfstream V Maintenance Manual, dated February 
28, 2020;
    (2) For Model GV-SP (G500 and G500-5000) airplanes: Section F 
and Table 12: Horizontal Stabilizer Inspection Table in section 05-
10-10, Airworthiness Limitations, of the Gulfstream G500-5000 
Maintenance Manual, dated March 15, 2021; or
    (3) For Model GV-SP (G550) airplanes: Section F and Table 12: 
Horizontal Stabilizer Inspection Table in section 05-10-10, 
Airworthiness Limitations, of the Gulfstream G550 Maintenance 
Manual, dated March 15, 2021.

(h) Applicable Customer Bulletins

    The customer bulletins specified in paragraphs (h)(1) through 
(3) of this AD contain procedures for compliance with the actions 
required by paragraph (i) of this AD for your applicable airplane 
designation.
    (1) Gulfstream GV Customer Bulletin No. 228, Revision B, dated 
October 31, 2019;
    (2) Gulfstream G500-5000 Customer Bulletin No. 190, Revision B, 
dated October 31, 2019; or
    (3) Gulfstream G550 Customer Bulletin No. 190, Revision B, dated 
October 31, 2019.

(i) Inspection

    For Model GV airplanes, all serial numbers, and Model GV-SP 
airplanes, serial numbers 5001 through 5158, where more than 132 
months have elapsed since the original certificate of airworthiness 
issue date (often referred to as entry into service date), as of the 
effective date of this AD: Within 12 months after the effective date 
of this AD, perform the horizontal stabilizer lower skin resonance 
C-Scan inspection (Part II inspection) for bond line corrosion and 
apply corrosion inhibiting compound (CIC) by following steps 6.2.a. 
through 6.2.e. and 6.3.a. of appendix A of the applicable customer 
bulletin listed in paragraph (h) of this AD.
    Note 2 to the introductory text of paragraph (i): The 
inspections listed in the applicable ALS revision in paragraph (g) 
of this AD must also be accomplished at the same time you perform 
the Part II inspection.
    (1) Within 48 months after applying CIC, repair the area using a 
method approved as specified in paragraph (j)(3) of this AD.
    (2) If there is bond line corrosion that exceeds the allowable 
damage limit, before further flight, repair the area using a method 
approved as specified in paragraph (j)(3) of this AD.

 (j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Atlanta ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (k)(1) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by a Gulfstream Engineering Authorized 
Representative (EAR) of the Gulfstream Organization Designation 
Authorization (ODA), that has been authorized by the Manager, 
Atlanta ACO Branch, to make those findings. To be approved, the 
repair, modification deviation, or alteration deviation must meet 
the certification basis of the airplane, and the approval must 
specifically refer to this AD.
    (4) For service information that contains steps that are labeled 
as Required for Compliance (RC), the following provisions apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. An AMOC is required for any deviations to RC steps, 
including substeps and identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(k) Related Information

    (1) For more information about this AD, contact Ronald Wissing, 
Aviation Safety Engineer, Atlanta ACO Branch, FAA, 1701 Columbia 
Avenue, College Park, GA 30337; phone: (404) 474-5552; fax: (404) 
474-5606; email: [email protected].
    (2) For service information identified in this AD, contact 
Gulfstream Aerospace Corporation, Technical Publications Dept., P.O. 
Box 2206, Savannah, GA 31402; phone: (800) 810-4853; fax: (912) 965-
3520; email: [email protected]; website: 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, MO 
64106. For information on the availability of this material at the 
FAA, call (816) 329-4148.

    Issued on October 28, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-24082 Filed 11-4-21; 8:45 am]
BILLING CODE 4910-13-P


