Airworthiness Directives; Gulfstream Aerospace Corporation Airplanes

[Federal Register Volume 88, Number 138 (Thursday, July 20, 2023)]
[Rules and Regulations]
[Pages 46677-46679]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-15255]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0659; Project Identifier AD-2022-01404-T; 
Amendment 39-22508; AD 2023-14-08]
RIN 2120-AA64


Airworthiness Directives; Gulfstream Aerospace Corporation 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Gulfstream Aerospace Corporation Model GVII-G600 airplanes. 
This AD was prompted by an addition of a life limit in the 
Airworthiness Limitations Section (ALS) for GVII-G600 flap yokes. The 
life limit for the GVII-G600 flap yokes was informed by a GVII-G500 
flap yoke failure that occurred during flight testing and, ultimately, 
resulted in additional test and analysis to establish more accurate 
life limits reflective of each model's design features and stress 
levels. The FAA is issuing this AD to require revising the existing ALS 
to prevent the GVII-G600 inboard flap yoke from remaining in service 
beyond its life limit. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective August 24, 2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-0659; 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: Jeffrey Johnson, Aviation Safety 
Engineer, FAA, 1701 Columbia Avenue, College Park, GA 30337; phone: 
404-474-5554; email: [email protected].

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 certain Gulfstream 
Aerospace Corporation Model GVII-G600 airplanes. The NPRM published in 
the Federal Register on April 6, 2023 (88 FR 20436). The NPRM was 
prompted by an addition of a life limit in the ALS for GVII-G600 
inboard flap actuator yoke fittings. Gulfstream revised the ALS to 
establish a life limit of 4,000 flight cycles. The FAA is issuing this 
AD to address decreased fatigue life of GVII-G600 inboard flap actuator 
yoke fittings and to prevent the GVII-G600 flap yoke from remaining in 
service beyond its life limit. An inboard flap actuator yoke fitting 
remaining in service beyond its life limit could result in the flaps 
being jammed in position, if fracture occurred. Additional failures in 
the flap actuator force limiter, or flap yoke actuator disconnect, 
could result in asymmetric flap positions leading to a loss of control 
of the airplane.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from Gulfstream Aerospace Corporation. 
The following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request To Clarify the Summary Section

    Gulfstream Aerospace Corporation states the summary statement does 
not accurately describe the condition or reason for this AD as the flap 
yoke fittings installed on GVII-G500 are not installed on any GVII-G600 
aircraft. Gulfstream has added a limitation to the GVII-G600 ALS based 
on a reevaluation of the damage tolerance analysis considering the 
GVII-G500 flap yoke fitting failure. The shaft diameters on both the 
inboard and outboard GVII-G600 flap yoke fittings are larger than the 
corresponding GVII-G500 configurations, and the operational stresses 
are lower.
    The FAA agrees with adopting Gulfstream's recommended language for 
the Summary with two exceptions. The FAA will continue to reference the 
unsafe condition because it follows previous NPRM language for ALS 
revisions when establishing life limits. The FAA will also continue to 
reference the GVII-G500 failure as the life limit for the GVII-G600 
flap yokes was informed by the GVII-G500 flap yoke failure that 
occurred during flight testing and resulted in additional test and 
analysis to establish more accurate life limits reflective of each 
model's design features and stress levels.

Request To Clarify the Background Section

    Gulfstream Aerospace Corporation states there is no design flaw on 
the GVII-G600 flap yoke. The flap yoke fittings installed on GVII-G500 
have a different design. A damage tolerance analysis was performed on 
the GVII-G600 inboard yoke fittings and determined that a life limit 
was necessary to protect the integrity of the flap actuation system. 
Gulfstream has requested the Background be changed to clarify this 
section.
    The FAA agrees with Gulfstream and has revised the Background 
section accordingly. While the GVII-G600 does have design features 
known to reduce fatigue life, the use of the term `design flaw' should 
not be applied to the GVII-G600 flap yoke fittings.

Request To Clarify Paragraph (e) Unsafe Condition

    Gulfstream Aerospace Corporation states the GVII-G600 design is 
much more robust than the GVII-G500 design, and there is no design flaw 
with the GVII-G600 flap yoke. Through analysis, Gulfstream determined a 
life limit was needed to address all threats required under 14 CFR 
25.571(a) and (b), including fatigue, corrosion, and accidental damage. 
Gulfstream acknowledges this AD is necessary to notify operators of a 
revision to the G600 ALS to incorporate life limits for the inboard 
flap actuator yoke fittings. Gulfstream requested a change to the 
unsafe paragraph to clarify the reason for this AD.
    The FAA agrees to revise the language in paragraph (e) to remove 
reference to the GVII-G500 investigation as a need to establish a life 
limit. While the GVII-G500 flap yoke fitting failure incident did 
inform the fatigue effects, the FAA

[[Page 46678]]

understands the GVII-G600 has unique design features and operating 
stress levels. The FAA disagrees with removal of the reference to the 
term ``unsafe condition'' from this section since all ADs are issued to 
address unsafe conditions in accordance with 14 CFR 39.5.

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, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Costs of Compliance

    The FAA estimates that this AD affects 41 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Revise ALS............................  1 work-hour x $85 per                N/A             $85          $3,485
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

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

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:

2023-14-08 Gulfstream Aerospace Corporation: Amendment 39-22508; 
Docket No. FAA-2023-0659; Project Identifier AD-2022-01404-T.

(a) Effective Date

    This airworthiness directive (AD) is effective August 24, 2023.

 (b) Affected ADs

    None.

 (c) Applicability

    This AD applies to Gulfstream Aerospace Corporation Model GVII-
G600 airplanes, certificated in any category, serial numbers 73001 
through 73051 inclusive.

 (d) Subject

    Air Transport Association (ATA) of America Code 27, Flight 
Controls.

 (e) Unsafe Condition

    This AD was prompted by an addition of a life limit in the 
Airworthiness Limitations Section (ALS) for GVII-G600 inboard flap 
actuator yoke fittings. The FAA is issuing this AD to address 
decreased fatigue life of GVII-G600 inboard flap actuator yoke 
fittings and to prevent the GVII-G600 flap yoke from remaining in 
service beyond its life limit. The unsafe condition, if not 
addressed, could result in the flaps being jammed in position, if 
fracture occurred. Additional failures in the flap actuator force 
limiter, or flap yoke actuator disconnect, could result in 
asymmetric flap positions leading to a loss of control of the 
airplane.

 (f) Compliance

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

 (g) Incorporation of ALS Revisions

    Within 30 days after the effective date of this AD, revise the 
existing ALS of the Instructions for Continued Airworthiness (ICA) 
or inspection program for your airplane by establishing a life limit 
of 4,000 flight cycles for the left-hand part number (P/N) 
73P5755033M005 and right-hand P/N 73P5755033M006 inboard flap yoke 
fittings.
    Note 1 to paragraph (g): The life limit in paragraph (g) of this 
AD is contained in table 2 in Section 05-10-10 of Gulfstream GVII-
G600 Aircraft Maintenance Manual, Revision 9, dated November 15, 
2022.

 (h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, East Certification 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 responsible Flight 
Standards 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 (i)(1) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.

 (i) Related Information

    (1) For more information about this AD, contact Jeffrey Johnson, 
Aviation Safety Engineer, FAA, 1701 Columbia Avenue, College Park, 
GA 30337; phone: 404-474-5554; email: [email protected].
    (2) For Gulfstream service information identified in this AD 
that is not incorporated by reference, contact Gulfstream Aerospace 
Corporation, Technical Publications Dept.,

[[Page 46679]]

P.O. Box 2206, Savannah, GA 31402-2206; telephone 800-810-4853; 
email [email protected]; website gulfstream.com/en/customer-support/. You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the availability 
of this material at the FAA, call 206-231-3195.

 (j) Material Incorporated by Reference

    None.

    Issued on July 13, 2023.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-15255 Filed 7-19-23; 8:45 am]
BILLING CODE 4910-13-P

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