preamble attached >>>
ADs updated daily at www.Tdata.com
2022-16-04 GULFSTREAM AEROSPACE CORPORATION: Amendment 39-22133; Docket No. FAA-2021-0958; Project Identifier 2019-CE-010-AD.
(a) EFFECTIVE DATE

    This airworthiness directive (AD) is effective September 7, 2022.

(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 al-
    ready 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
    Chapter 05,  Time Limits/Maintenance Checks,  of the Gulfstream V Air-
    craft Maintenance Manual, Revision 55, dated March 15, 2022.

(2) For Model GV-SP (G500 and G500-5000) airplanes: Section F and Table 11
    Horizontal Stabilizer Inspection Table in Section 05-10-10, Airworthi-
    ness Limitations, of Chapter 05,  Time Limits / Maintenance Checks, of
    the Gulfstream G500-5000  Aircraft  Maintenance  Manual,  Revision 36,
    dated March 15, 2022.

(3) For Model GV-SP (G550) airplanes:  Section F and Table 11:  Horizontal
    Stabilizer Inspection Table in Section 05-10-10, Airworthiness Limita-
    tions, of Chapter 05 Time Limits/Maintenance Checks, of the Gulfstream
    G550 Aircraft Maintenance Manual, Revision 36, dated March 15, 2022.

(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 Octo-
    ber 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: 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):  Operators may align the
inspections listed in the applicable ALS revision in paragraph (g) of this
AD with the Part II inspection.

(1) Within 48 months after applying CIC, repair all bond line corrosion.

(2) If there is bond line corrosion  that  exceeds  the  allowable  damage
    limits in Table 2 of appendix A  of  the  applicable customer bulletin
    listed in paragraph (h) of this AD,  or  other allowable damage limits
    established by  an  appropriately  authorized  Gulfstream Organization
    Designation Authorization (ODA) unit member, repair all bond line cor-
    rosion before further flight using a repair  approved by the FAA or an
    appropriately authorized Gulfstream ODA unit member.

(i) For a repair method to be approved  by the FAA,  the FAA's approval of
    the repair must specifically refer to this AD.

(ii) For a repair method  to be approved  by a Gulfstream ODA unit member,
     the unit member must be authorized  in writing by the Manager  of the
     Atlanta ACO Branch  to  approve  repairs for this AD,  and  the  unit
     member's approval of the repair must specifically refer to this AD.

(j) CREDIT FOR PREVIOUS ACTIONS

    You may take credit for the ALS revision  required by paragraph (g) of
    this AD if you revised the ALS  before  the  effective date of this AD
    using the service information  specified in paragraph (j)(1), (2),  or
    (3) of this AD, as applicable to your airplane designation.

(1) For Model GV airplanes: Section F and Table 12:  Horizontal Stabilizer
    Inspection Table in Section 05-10-10,  Airworthiness  Limitations,  of
    Chapter 05,  Time Limits/Maintenance Checks,  of the Gulfstream V Air-
    craft Maintenance Manual, Revision 53, dated February 28, 2020.

(2) For Model GV-SP (G500 and G500-5000) airplanes: Section F and Table 11
    Horizontal Stabilizer Inspection Table in Section 05-10-10, Airworthi-
    ness Limitations,  of Chapter 05,  Time Limits/Maintenance Checks,  of
    the Gulfstream G500-5000  Aircraft  Maintenance  Manual,  Revision 34,
    dated March 15, 2021.

(3) For Model GV-SP (G550) airplanes:  Section F and Table 12:  Horizontal
    Stabilizer Inspection Table in Section 05-10-10, Airworthiness Limita-
    tions, of Chapter 05, Time Limits/Maintenance Checks of the Gulfstream
    G550 Aircraft Maintenance Manual, Revision 34, dated March 15, 2021.

(k) 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 (l)(1) of this AD.

(2) Before using any approved AMOC,  notify your appropriate principal in-
    spector,  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 ODA that has been authorized by the Manager, Atlanta
    ACO Branch, to make those findings.  To be approved, the repair, modi-
    fication 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 Re-
    quired 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,  that are required  by paragraph (i)
    of this AD must be done to comply with this AD.  An  AMOC  is required
    for any deviations to RC steps required  by paragraph (i)  of this AD,
    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, includ-
     ing substeps and identified figures,  can still be done as specified,
     and the airplane can be put back in an airworthy condition.

(l) 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; email 9-ASO-ATLACO-ADs@faa.gov.

(2) Service information identified in this AD  that is not incorporated by
    reference is available at the addresses specified in paragraphs (m)(3)
    and (4) of this AD.

(m) MATERIAL INCORPORATED BY REFERENCE

(1) The Director of the Federal Register  approved  the  incorporation  by
    reference of the service information  listed in this paragraph under 5
    U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable  to do the actions
    required by this AD, unless the AD specifies otherwise.

(i) Gulfstream G500-5000 Customer Bulletin No. 190 Revision B, dated Octo-
    ber 31, 2019.

(ii) Gulfstream G550 Customer Bulletin No. 190, Revision B,  dated October
     31, 2019.

(iii) Gulfstream GV Customer Bulletin No. 228,  Revision B,  dated October
      31, 2019.

(iv) Section F and Table 11:  Horizontal Stabilizer  Inspection  Table  in
     Section  05-10-10,  Airworthiness  Limitations,  of Chapter 05,  Time
     Limits/Maintenance Checks, of the Gulfstream G500-5000 Aircraft Main-
     tenance Manual, Revision 36, dated March 15, 2022.

(v) Section F and Table 11: Horizontal Stabilizer Inspection Table in Sec-
    tion 05-10-10, Airworthiness Limitations, of Chapter 05,  Time Limits/
    Maintenance Checks, of the Gulfstream G550 Aircraft Maintenance Manual
    Revision 36, dated March 15, 2022.

(vi) Section F and Table 12:  Horizontal  Stabilizer  Inspection  Table in
     Section  05-10-10,  Airworthiness  Limitations,  of Chapter 05,  Time
     Limits / Maintenance Checks, of the Gulfstream V Aircraft Maintenance
     Manual, Revision 55, dated March 15, 2022.

(3) For service information identified in this AD, contact Gulfstream Aer-
    ospace Corporation, Technical Publications Dept, P.O. Box 2206, Savan-
    nah, GA 31402; phone: (800) 810-4853; fax: (912) 965-3520; email: pubs
    @gulfstream.com; website: www.gulfstream.com/en/customer-support/.

(4) You may view this service information at 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
    (817) 222-5110.

(5) You may view this service information  that is incorporated  by refer-
    ence at the National Archives and Records Administration  (NARA).  For
    information on the availability of this material  at NARA,  email: fr.
    inspection@nara.gov,  or go to: www.archives.gov/federal-register/cfr/
    ibr-locations.html.

Issued on July 26, 2022.  Christina Underwood, Acting Director, Compliance
& Airworthiness Division, Aircraft Certification Service.

FOR FURTHER INFORMATION CONTACT: Ronald Wissing, Aviation Safety Engineer,
Atlanta ACO Branch,  FAA,  1701 Columbia Avenue,  College Park,  GA 30337;
phone: (404) 474-5552; email: 9-ASO-ATLACO-ADs@faa.gov.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0958; Project Identifier 2019-CE-010-AD; Amendment
39-22133; AD 2022-16-04]
RIN 2120-AA64

Airworthiness Directives; Gulfstream Aerospace Corporation Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Gulfstream Aerospace Corporation (Gulfstream) Model GV and GV-SP
airplanes. This AD was prompted by corrosion of the horizontal
stabilizer lower bonded skin assemblies. This AD requires inspecting
the horizontal stabilizer lower skin and associated bonded doublers and
bonded stringers, repairing any area with corrosion beyond allowable
damage limits, and incorporating revisions to the airworthiness
limitations section (ALS) in the existing aircraft maintenance manual
(AMM) or progressive maintenance program. The FAA is issuing this AD to
address the unsafe condition on these products.

DATES: This AD is effective September 7, 2022.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of September 7,
2022.

ADDRESSES: For service information identified in this final rule,
contact Gulfstream Aerospace Corporation, Technical Publications Dept.,
P.O. Box 2206, Savannah, GA 31402; phone: (800) 810-4853; fax: (912)
965-3520; email: pubs@gulfstream.com; website: 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 (817) 222-5110. It is also available at
www.regulations.gov by searching for and locating Docket No. FAA-2021-
0958.

Examining the AD Docket

You may examine the AD docket at 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 final rule, any comments
received, and other information. The address for Docket Operations is
U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 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) 474-5552; email: 9-ASO-ATLACO-ADs@faa.gov.

SUPPLEMENTARY INFORMATION:

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
and GV-SP airplanes. The NPRM published in the Federal Register on
November 5, 2021 (86 FR 61088). The NPRM was prompted by 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 did not reliably detect bond line
corrosion and added a repetitive non-destructive testing (NDT)
inspection to detect the damage. In the NPRM, the FAA proposed to
require inspecting the horizontal stabilizer lower skin and associated
bonded doublers and bonded stringers, repairing any area with corrosion
beyond allowable damage limits, and incorporating revisions to the ALS
in the existing AMM. The FAA is issuing this AD to address the unsafe
condition on these products.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from one commenter, Gulfstream. The
following presents the comments received on the NPRM and the FAA's
response to each comment.

Request To Clarify Information in the Preamble

Gulfstream requested that the FAA revise a phrase describing part
of the proposed corrective action under SUMMARY and under the
``Proposed AD Requirements in This NPRM'' section of SUPPLEMENTARY
INFORMATION. Gulfstream requested the FAA change ``repairing the area
susceptible to corrosion'' to ``identify if a repair is required.''
Gulfstream stated that the bonded structure is ``susceptible'' to
corrosion but does not necessarily require ``repair'' because the need
for repair is based on the inspection results.
The FAA agrees that all areas susceptible to corrosion do not
necessarily require repair. The FAA has revised the SUMMARY of this
final rule to clarify that only areas with corrosion that exceeds
allowable damage limits need to be repaired. The ``Proposed AD
Requirements in This NPRM'' section is not restated in this final rule,
so a change is unnecessary.

Request To Revise the Description of a Service Document

Gulfstream requested the FAA change the description of Gulfstream
Service Letter Document No. GSL505510019, Revision E, dated September
3, 2021, in the ``Other Related Service Information'' section of the
preamble. In the NPRM, the FAA stated that the service letter contains
procedures for applying on-wing corrosion inhibiting compound (CIC) to
the horizontal stabilizer. Gulfstream advised that this description is
inaccurate because although the service letter specifies applying CIC,
it references another service letter for the application instructions.
Gulfstream requested that the preamble state instead that this service
letter ``contains allowable damage limits for the horizontal stabilizer
assembly.''
The FAA agrees and has revised this final rule accordingly.

Request Regarding the Airplane Effectivity Range

Gulfstream requested that the FAA remove language in the preamble
explaining that the proposed AD would apply to all Model GV and GV-SP
airplanes, while the service bulletins exclude certain serial-numbered
airplanes. Gulfstream also requested that the inspection proposed in
paragraph (i) of the proposed AD not be required for these same serial-
numbered airplanes. Gulfstream stated that four airplanes were excluded
from the effectivity of the customer bulletin because the airplanes had
not yet reached the baseline compliance time for doing the initial
``Part II'' inspection of the horizontal stabilizer lower skin.
Gulfstream explained that removing those four airplanes from the
inspection portion of the proposed AD would not have an impact on
safety, because those airplanes will be inspected in accordance with
the 144-month entry into service inspection specified in Chapter 5 of
the AMM.
The FAA disagrees. Gulfstream's request appears to be based on the
compliance time for those four airplanes and not whether they are
subject to the unsafe condition identified in this AD.

The inspection required by paragraph (i) of this AD is necessary to
correct the unsafe condition on all Model GV-SP airplanes with a serial
number in the range of 5001 through 5158. The FAA did not change this
AD based on this comment.

Request To Include Terminating Action

Gulfstream requested that the FAA add terminating actions for the
ALS revision proposed in paragraph (g) and for the inspection proposed
in paragraph (i) of the proposed AD. Gulfstream stated that otherwise
owners will have to comply for an indefinite period.
The FAA does not agree because paragraphs (g) and (i) of this AD
require one-time actions and not repetitive actions; therefore,
terminating action is not necessary. Once an operator has revised the
maintenance or inspection program for its airplane by incorporating the
applicable ALS revision, the operator has complied with paragraph (g)
of this AD. As explained in the NPRM, although the service bulletins
allow the inspection to be repeated indefinitely every 48 months, this
AD does not. Instead, paragraph (i) of this AD requires the inspection
once, and any necessary repairs within 48 months after the inspection.
The FAA did not change this AD based on this comment.

Request To Remove Entry Into Service Criteria

Gulfstream requested that the FAA revise paragraph (i) of the
proposed AD to remove the criteria that the inspection be required for
airplanes ``where more than 132 months have elapsed since the original
certificate of airworthiness issue date (often referred to as entry
into service date).'' In support, Gulfstream explained that this
language is no longer applicable because all affected airplanes have
accumulated 132 months since entry into service. In addition,
Gulfstream noted that the entry into service date and the original
certificate of airworthiness issue date are two different dates and are
not interchangeable.
The FAA agrees and has revised paragraph (i) of this AD
accordingly.

Request To Remove Note Regarding ALS Inspections

Gulfstream requested that the FAA remove Note 2 to the introductory
text of paragraph (i) of the proposed AD, which advised that the
inspections listed in the ALS revision (required by paragraph (g) of
the proposed AD) must be done at the same time as the Part II
inspection. Gulfstream stated it is not necessary to mandate the ALS
maintenance inspections at the same time as the Part II inspection of
the horizontal stabilizer lower skin for bond line corrosion.
Gulfstream explained there is no reason to accomplish these actions
together and doing so could result in duplication of efforts.
The FAA agrees that, to correct the unsafe condition, the ALS
maintenance inspections are not required at the same time as the
airworthiness inspection of the horizontal stabilizer lower skin for
bond line corrosion. However, operators may align these inspections to
establish a baseline for the required repetitive inspection intervals.
The FAA has revised Note 2 to the introductory text of paragraph (i) of
this AD accordingly.

Request To Clarify Note 2 of the Proposed AD

Gulfstream requested the FAA clarify the intent and placement of
Note 2, which was located after the introductory text of paragraph (i)
of the proposed AD and before paragraphs (i)(1) and (2) of the proposed
AD. Gulfstream explained that due to the placement of the note, it is
unclear whether paragraphs (i)(1) and (2) of the proposed AD are part
of the note or whether they are lower level paragraphs of paragraph (i)
of the proposed AD. Gulfstream also stated that this note does not
follow FAA policy and guidance, which states that notes are for
informational purposes, because it introduces a requirement not
otherwise stated in the AD.
Paragraphs (i)(1) and (2) of this AD are lower level paragraphs of
paragraph (i) of this AD. Paragraph (i) of this AD requires inspecting
the horizontal stabilizer lower skin for bond line corrosion and
applying CIC. Paragraphs (i)(1) and (2) of this AD provide the
compliance time for repairing any corrosion found as a result of the
inspection: either within 48 months after applying CIC if the corrosion
is within allowable damage limits, or before further flight if any
corrosion exceeds allowable damage limits. The placement of the note
after the introductory text of paragraph (i) of this AD follows the
formatting requirements for regulatory documents in the Office of the
Federal Register's Document Drafting Handbook. The FAA did not change
this AD based on this comment.

Request To Remove Paragraphs (i)(1) and (2) of the Proposed AD

Gulfstream requested that the FAA remove paragraphs (i)(1) and (2)
of the proposed AD, which proposed to require, after performing the
Part II inspection, repairing the area using a method approved by
Gulfstream's Organization Designation Authorization (ODA). Gulfstream
stated that these paragraphs are unnecessary and redundant with normal
operating and repair station procedures. Gulfstream further noted that
the FAA's regulations in 14 CFR part 43 already require that aircraft
with corrosion exceeding allowable damage limits be repaired and in an
airworthy state before approval for return to service.
The FAA disagrees with removing paragraph (i)(2) of this AD. For
corrosion that exceeds allowable damage limits, the FAA finds that the
repair mandated by paragraph (i)(2) of this AD is required to address
the identified unsafe condition. Aircraft found with corrosion that
exceeds allowable damage limits will require corrective action that may
appreciably affect the structural strength of the airframe. FAA-
approved (or ODA-approved) engineering data will likely be required to
return the aircraft to service. In addition, the FAA is unaware of a
repair procedure or specification that could be used to approve all
affected aircraft for return to service. Rather, unique, airplane-
specific repairs will be necessary.
However, the FAA agrees that standard maintenance practices are
sufficient to repair corrosion within allowable limits and has revised
paragraph (i)(1) of this AD accordingly. The FAA has also clarified the
scope of the repair required after the CIC application by revising
paragraph (i)(1) of this AD. Instead of the broader requirement to
repair ``the area,'' that paragraph now specifies repairing ``all bond
line corrosion.'' This change will decrease the burden of this
requirement on operators while appropriately addressing bond line
corrosion.

Request To Address Airplanes Repaired Prior to AD Issuance

Gulfstream requested that, for airplanes that have been
``permanently'' repaired prior to AD issuance, the FAA give operators
the full benefit of the repair. Alternatively, Gulfstream suggested the
FAA allow a 48-month compliance time, the same as for an airplane with
allowable bond line corrosion, to avoid immediately grounding
airplanes.
The FAA agrees operators should have the benefit of repairs
accomplished by Gulfstream before the effective date of the AD,
provided Gulfstream's ODA approves those repairs as restoring the
airplane to its type certification basis. The FAA infers that by
``permanent'' repair, Gulfstream is referring to repairs to airplanes
found with corrosion exceeding allowable damage limits.

Gulfstream has accomplished these repairs on many of the affected
airplanes prior to the effective date of the AD under its ODA
procedures. In the NPRM, the FAA proposed that these repairs must be
made using a method approved by Gulfstream's ODA under the procedures
for alternative methods of compliance (AMOCs). In order to more
efficiently give operators the benefit of these repairs, the FAA has
revised paragraph (i)(2) of this AD to require an FAA-approved or ODA-
approved repair method without using AMOC procedures. The document
approving the repair method must still specifically reference this AD.
The FAA finds that the additional compliance time requested by
Gulfstream is unnecessary. Operators have 12 months after the effective
date of this AD to perform the resonance C-Scan (Part II) inspection
required by the introductory text of paragraph (i) of this AD, apply
CIC, and repair any corrosion that exceeds allowable limits using an
FAA-approved or ODA-approved method. Operators have this same 12-month
compliance time to take credit for any actions ``already done'' under
paragraph (f) of this AD, including ``permanent'' repairs that
Gulfstream's ODA may need to approve by specifically referring to this
AD.

Request To Clarify Allowable Damage Limit

Gulfstream requested that the FAA revise paragraph (i)(2) of the
proposed AD to clarify that the term ``allowable damage limit'' means
the allowable damage limits provided by Gulfstream as the original
equipment manufacturer. Gulfstream explained that these limits are
defined in various Gulfstream documents.
The FAA agrees to clarify the term ``allowable damage limit'' and
has revised paragraph (i)(2) of this AD to specify that the limits are
those in the applicable service information or those approved by
Gulfstream's ODA.

Request To Clarify Required for Compliance (RC) Steps

Gulfstream requested that the FAA revise paragraph (j)(4)(i) of the
proposed AD (paragraph (k)(4)(i) of this AD) to clarify that operators
only need to comply with the RC steps required by paragraph (i) of the
proposed AD. Gulfstream noted that paragraph (j)(4)(i), as proposed,
implies that operators would have to do all of the actions labeled
``RC'' in the customer bulletin, even though the proposed AD does not
specify all of those steps.
The FAA agrees and has revised paragraph (k)(4)(i) of this AD
accordingly.

Additional Changes Made to This AD

After the NPRM was issued, Gulfstream revised the portions of the
ALS that are relevant to the proposed AD: Section F and Table 11:
Horizontal Stabilizer Inspection Table in Section 05-10-10,
Airworthiness Limitations, of Chapter 05, Time Limits/Maintenance
Checks, of the Gulfstream G500-5000 Aircraft Maintenance Manual,
Revision 36, dated March 15, 2022; Section F and Table 11: Horizontal
Stabilizer Inspection Table in Section 05-10-10, Airworthiness
Limitations, of Chapter 05, Time Limits/Maintenance Checks, of the
Gulfstream G550 Aircraft Maintenance Manual, Revision 36, dated March
15, 2022; and Section F and Table 12: Horizontal Stabilizer Inspection
Table in Section 05-10-10, Airworthiness Limitations, of Chapter 05,
Time Limits/Maintenance Checks, of the Gulfstream V Aircraft
Maintenance Manual, Revision 55, dated March 15, 2022. The FAA reviewed
these revisions and determined they do not require additional work or
impose any substantive changes to those proposed in the NPRM.
Therefore, the FAA has revised paragraph (g) of this AD to require
incorporating these later-issued revisions of the applicable section
and table of Section 05-10-10 of the ALS. The FAA has also added
paragraph (j) of this AD to provide credit for operators who have
revised their ALS before the effective date of this AD using the ALS
revisions specified in the NPRM. Subsequent paragraphs have been re-
designated accordingly.
The FAA has also updated the ALS table number reference in
paragraphs (g)(2) and (3) of this AD. This reference changed from Table
12 to Table 11 when Gulfstream revised Section 05-10-10 of the
applicable AMMs.

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 the changes described
previously, 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 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 Section F and Table 12: Horizontal Stabilizer
Inspection Table in Section 05-10-10, Airworthiness Limitations, of
Chapter 05, Time Limits/Maintenance Checks, of the Gulfstream V
Aircraft Maintenance Manual, Revision 55, dated March 15, 2022; Section
F and Table 11: Horizontal Stabilizer Inspection Table in Section 05-
10-10, Airworthiness Limitations, of Chapter 05, Time Limits/
Maintenance Checks, of the Gulfstream G500-5000 Aircraft Maintenance
Manual, Revision 36, dated March 15, 2022; and Section F and Table 11:
Horizontal Stabilizer Inspection Table in Section 05-10-10,
Airworthiness Limitations, of Chapter 05, Time Limits/Maintenance
Checks, of the Gulfstream G550 Aircraft Maintenance Manual, Revision
36, dated March 15, 2022. 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.
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.

Other Related Service Information

The FAA also reviewed the following service documents related to
this final rule.
Gulfstream Service Letter Document No. GSL505510019,
Revision E, dated September 3, 2021, which contains allowable damage
limits for the horizontal stabilizer assembly.
Gulfstream Service Letter Document No. GSL505510020,
Revision C, dated March 12, 2020, which contains procedures for
applying CIC to the horizontal stabilizer.
Gulfstream V Nondestructive Testing Procedures Manual
Chapter 05-00-00, 1. Horizontal Stabilizer Lower Skin Resonance C-
Scan--NDT Procedure.

Differences Between This 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 AD are listed below.
The customer bulletins exclude certain serial-numbered
airplanes inspected by Gulfstream, but this AD applies to all Model GV
and GV-SP airplanes.
The customer bulletins include an optional horizontal
stabilizer lower skin resonance A-Scan NDT inspection (referred to in
the customer bulletins as ``Part I Inspection'') for critical areas of
the horizontal stabilizer bonded lower skin assemblies, but this AD
does not require the Part I Inspection.
The customer bulletins allow the horizontal stabilizer
lower skin resonance C-Scan NDT inspection (referred to in the customer
bulletins as a ``Part II Inspection'') and application of CIC to be
repeated indefinitely every 48 months. This AD only allows the Part II
inspection to be performed one time and, within 48 months after the
inspection, requires approved repairs.
The customer bulletins contain actions labeled RC, and the
language in the customer bulletins and in paragraph (k)(4) of this 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 affects up to 694 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:

Estimated Costs

Action Labor cost Parts cost Cost per airplane Cost on U.S. operators
Resonance C-Scan NDT (Part II) inspection and CIC application 80 work-hours x $85 per hour = $6,800 Not applicable $6,800 $2,196,400 (for 323 airplanes)
AMM revision 1 work-hour x $85 per hour = $85 Not applicable 85 $58,990 (for 694 airplanes)

The extent of corrosion found during the 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

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.

List of Subjects in 14 CFR Part 39

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

The Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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: