[Federal Register Volume 86, Number 87 (Friday, May 7, 2021)]
[Proposed Rules]
[Pages 24546-24549]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-09243]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0156; Project Identifier AD-2020-01594-T]
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 certain Gulfstream Aerospace Corporation (Gulfstream) Model GVII-
G500 airplanes. This proposed AD results from flap yoke fittings with 
design features that cause decreased fatigue life. This proposed AD 
would require replacing the flap inboard and outboard yoke fitting 
assemblies and establishing a 20,000 flight cycle life limit for the 
fittings. 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 June 21, 
2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR

[[Page 24547]]

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; email: pubs@gulfstream.com; 
website: https://www.gulfstream.com/en/customer-support/. You may view 
this service information at the 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-2021-0156; 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: Jeff Johnson, Aviation Safety 
Engineer, Atlanta ACO Branch, FAA, 1701 Columbia Ave., College Park, GA 
30337; phone: (404) 474-5554; fax: (404) 474-5606; email: 
jeffrey.d.johnson@faa.gov.

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-2021-0156; Project Identifier 
AD-2020-01594-T'' 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 Jeff 
Johnson, Aviation Safety Engineer, Atlanta ACO Branch, FAA, 1701 
Columbia Ave., 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

    During flight testing of a Gulfstream Model GVII-G500 airplane, 
when the aircraft was configuring for a steep approach test point, the 
crew received a flap failure message. After landing, inspection 
revealed that the left-hand flap track `B' yoke had become disconnected 
due to structural failure. Gulfstream's investigation to determine the 
root cause of the failure revealed that the flap yoke fittings for 
certain serial-numbered Gulfstream Model GVII-G500 airplanes have 
design features that cause decreased fatigue life. The unsafe design 
features include insufficient shaft diameter, a small fillet radius 
detail at the top of the shaft, and a rough surface finish allowance, 
which collectively attribute to a potential yoke fitting failure. These 
design features ultimately cause higher stress concentrations leading 
to premature and fast-fracture overload of the flap actuator yoke at 
the junction of the fitting shaft and yoke clevis.
    This condition, if not addressed, could result in failure of the 
flap yoke fitting during flap transition, which could cause the flaps 
to stop moving. This, combined with additional failures in the flap 
actuator force limiter or flap yoke actuator disconnect, could result 
in asymmetric flap positions, leading to a loss of airplane control.

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 GVII-G500 Aircraft Service Change No. 
032, Initial Issue, dated November 20, 2020 (Gulfstream ASC No. 032). 
This service information specifies procedures for replacing the flap 
inboard and outboard yoke fitting assemblies and upper bushings. 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 Gulfstream GVII-500 Customer Bulletin No. 
045, Initial Issue, dated November 20, 2020. This service information 
specifies the compliance time and additional information for Gulfstream 
ASC No. 032. The FAA also reviewed Gulfstream Aerospace GVII-G500 
Aircraft Maintenance Manual (AMM) Document Number GAC-AC-GVII-G500-AMM-
0001, Revision 7, dated December 15, 2020. This document contains 
revised airworthiness limitations, maintenance checks, and inspections.

Proposed AD Requirements in This NPRM

    This proposed AD would require replacing the flap inboard and 
outboard yoke fitting assemblies and updating chapter 5 of your 
existing AMM to incorporate a 20,000 flight cycle life limit.

Differences Between This Proposed AD and the Service Information

    Gulfstream ASC No. 032 contains actions labeled ``Required for 
Compliance'' (RC), and the language in the ASC and in paragraph (h)(3) 
of this AD indicates 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 Gulfstream ASC No. 032 that are labeled as 
RC. Operators only need to comply with the RC steps specified in 
paragraph (g) of this AD.

[[Page 24548]]

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 85 airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replace the flap inboard and         83.5 work-hours x $85 per         $8,015.00      $15,112.50   $1,284,562.50
 outboard yoke fitting assemblies     hour = $7,097.50.
 and update the existing AMM.
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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:

Gulfstream Aerospace Corporation: Docket No. FAA-2021-0156; Project 
Identifier AD-2020-01594-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by June 21, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Gulfstream Aerospace Corporation Model GVII-
G500 airplanes, serial numbers 72001 through 72085, certificated in 
any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code 5753, Trailing Edge 
Flaps.

(e) Unsafe Condition

    This AD results from flap yoke fittings with design features 
that cause decreased fatigue life. The FAA is issuing this AD to 
prevent failure of the flap yoke fitting. The unsafe condition, if 
not addressed, could result in failure of the flap yoke fitting 
during flap transition, which could cause the flaps to stop moving. 
This, combined with additional failures in the flap actuator force 
limiter or flap yoke actuator disconnect, could result in asymmetric 
flap positions leading to a loss of airplane control.

(f) Compliance

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

(g) Required Actions

    (1) Within 24 months after the effective date of this AD or 
within 500 flight cycles after the effective date of this AD, 
whichever occurs first, replace each flap yoke fitting assembly by 
following Sections III.A.2 through III.D of the Modification 
Instructions in Gulfstream GVII-G500 Aircraft Service Change No. 
032, Initial Issue, dated November 20, 2020 (Gulfstream ASC No. 
032).
    (2) Within 24 months after the effective date of this AD, revise 
the existing Airworthiness Limitations section of the Instructions 
for Continued Airworthiness or aircraft inspection program for your 
airplane by establishing a life limit of 20,000 flight cycles for 
each flap yoke fitting part number 72P5755095A001, 72P5755096A001, 
72P5755097A001, and 72P5755098A001.

    Note 1 to paragraph (g)(2): Section 05-10-10 of Gulfstream 
Aerospace GVII-G500 Aircraft Maintenance Manual (AMM) Document 
Number GAC-AC-GVII-G500-AMM-0001, Revision 7, dated December 15, 
2020, contains the life limit in paragraph (g)(2) of this AD.

(h) 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 Related Information.
    (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) 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

[[Page 24549]]

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.

(i) Related Information

    (1) For more information about this AD, contact Jeff Johnson, 
Aviation Safety Engineer, Atlanta ACO Branch, FAA, 1701 Columbia 
Ave., College Park, GA 30337; phone: (404) 474-5554; fax: (404) 474-
5606; email: jeffrey.d.johnson@faa.gov.
    (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; email: 
pubs@gulfstream.com; 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 April 28, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-09243 Filed 5-6-21; 8:45 am]
BILLING CODE 4910-13-P


