Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 84, Number 227 (Monday, November 25, 2019)]
[Rules and Regulations]
[Pages 64723-64725]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-25474]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0323; Product Identifier 2019-NM-026-AD; Amendment 
39-19785; AD 2019-22-06]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company 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 The Boeing Company Model 737-800 series airplanes. This AD was 
prompted by reports of inadequate clearance between a certain fuel 
quantity indicating system (FQIS) tank unit and a certain reinforcement 
angle added as a part of a certain split winglet modification. This AD 
requires a detailed inspection to measure the clearance between the 
FQIS tank unit and a certain reinforcement angle installed as a part of 
the split winglet modification, and repair if necessary. The FAA is 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective December 30, 2019.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publications listed in this AD as of December 
30, 2019.

ADDRESSES: For service information identified in this final rule, 
contact Aviation Partners Boeing, 2811 S 102nd Street, Suite 200, 
Seattle, WA 98168; telephone 206-830-7699; internet https://www.aviationpartnersboeing.com. You may view this service information 
at the FAA, Transport Standards Branch, 2200 South 216th St., Des 
Moines, WA. For information on the availability of this material at the 
FAA, call 206-231-3195. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2019-
0323.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2019-
0323; 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, the regulatory evaluation, 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: Christopher Baker, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3552; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain The Boeing 
Company Model 737-800 series airplanes. The NPRM published in the 
Federal Register on May 14, 2019 (84 FR 21279). The NPRM was prompted 
by reports of inadequate clearance between a FQIS tank unit at rib 21 
and the stringer U-14 reinforcement angle added as a part of a split 
winglet modification per supplemental type certificate (STC) ST00830SE. 
The NPRM proposed to require a detailed inspection to measure the 
clearance between the FQIS tank unit and a certain reinforcement angle 
installed as a part of the split winglet modification, and repair if 
necessary.
    The FAA is issuing this AD to address inadequate clearance between 
a certain FQIS tank unit and a certain reinforcement angle upon 
accomplishment of a certain split winglet modification, which could 
result in a potential source of ignition in a fuel tank and consequent 
fire, overpressure, and structural failure of the wing and possible 
loss of the airplane.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Support for the NPRM

    United Airlines stated that it concurs with the proposed actions 
with no additional comments.

Request To Clarify Paragraph (c) Applicability of the Proposed AD

    Boeing and Aviation Partners Boeing (APB) requested that we revise 
paragraph (c) of the proposed AD to include more detail as to which 
airplanes are affected. Boeing explained that STC ST00830SE has 
multiple configurations, and the proposed AD is applicable to only one 
configuration; airplanes in that configuration are identified in 
Aviation Partners Boeing Service Bulletin AP737-57-020, dated April 5, 
2018. APB clarified further that STC ST00830SE includes both blended 
and split scimitar winglet configurations, but operators with aircraft 
modified to receive the blended winglets do not install the 
reinforcement that may interfere with the tank unit, and are not 
subject to the unsafe condition and requirements of the proposed AD.
    The FAA agrees with the commenters' request for the reasons 
provided. The FAA has revised paragraph (c) of this AD to state that 
this AD applies to The Boeing Company Model 737-800 series airplanes, 
certificated in any category, line numbers 4919 through 5063 inclusive, 
modified with split winglets per STC ST00830SE and listed in Aviation 
Partners Boeing Service Bulletin AP737-57-020, dated April 5, 2018.

Request To Delete ODA Provisions

    Boeing and APB requested that the FAA delete paragraph (h)(3) of 
the proposed AD because The Boeing Company Organization Designation 
Authorization (ODA) does not have AMOC authority for the referenced 
split scimitar winglet STC ST00830SE.
    The FAA agrees with the request for the reasons provided. The FAA 
has removed paragraph (h)(3) of this AD.

Request To Clarify the Cost of Compliance Section of the NPRM

    Boeing requested that the FAA revise the Cost of Compliance section 
of the NPRM to clarify that APB is responsible for warranty coverage. 
Boeing reasoned that the NPRM's language of ``according to the 
manufacturer . . .'' did not specify which manufacturer, Boeing or APB, 
would be responsible for warranty coverage.
    The FAA agrees with the request for the reasons provided. The FAA 
has revised the Costs of Compliance section of this final rule to 
clarify that APB is the manufacturer responsible for warranty coverage.

[[Page 64724]]

Request To Revise the Summary of the NPRM

    Boeing requested that the FAA revise the SUMMARY section of the 
NPRM to further clarify which airplanes are affected by the proposed 
AD. Boeing suggested that the FAA add ``modified with split winglets 
and listed in Aviation Partners Boeing Service Bulletin AP737-57-020, 
dated April 5, 2018,'' as a qualifier for the airplanes affected. In 
addition, Boeing requested that the FAA clarify what prompted the AD 
and the requirements of the AD by adding language that makes clear the 
reinforcement angle was added as a part of the referenced split 
scimitar winglet STC ST00830SE.
    The FAA partially agrees with the request. The FAA disagrees with 
the request to add the qualifying statement of ``modified with split 
winglets and listed in Aviation Partners Boeing Service Bulletin AP737-
57-020, dated April 5, 2018,'' because the SUMMARY section serves only 
as a brief introduction to the NPRM, and the level of detail requested 
by Boeing is reserved for the Regulatory Section of the proposed AD. As 
discussed earlier, the FAA has revised paragraph (c) of this AD to 
clarify that this AD applies only to The Boeing Company Model 737-800 
series airplanes modified with split winglets per STC ST00830SE and 
listed in Aviation Partners Boeing Service Bulletin AP737-57-020, dated 
April 5, 2018. However, the FAA has revised the SUMMARY section of the 
final rule to clarify that a certain reinforcement angle was added as a 
part of a certain split winglet modification.
    The FAA agrees with Boeing's request to clarify what prompted the 
NPRM and the requirements of the NPRM, for the reasons provided. The 
SUMMARY section of this AD has been revised accordingly.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule with the changes described previously 
and minor editorial changes. The FAA has determined that these minor 
changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Aviation Partners Boeing Service Bulletin AP737-
57-020, dated April 5, 2018. This service information describes 
procedures for a detailed inspection to measure the clearance between 
the FQIS tank unit at rib 21 (WSTA 617) and stringer U-14 reinforcement 
angle on the left-hand wing, and repair including trimming the stringer 
U-14 reinforcement angle to obtain minimum clearance. 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.

Costs of Compliance

    The FAA estimates that this AD affects 16 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
----------------------------------------------------------------------------------------------------------------
Detailed Inspection................  7 work-hours x $85 per hour              $0            $595          $9,520
                                      = $595.
----------------------------------------------------------------------------------------------------------------

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

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Repair.....................................  4 work-hours x $85 per hour = $340.              $0            $340
----------------------------------------------------------------------------------------------------------------

    According to Aviation Partners Boeing, some or all of the costs of 
this AD may be covered under warranty, thereby reducing the cost impact 
on affected individuals. The FAA does not control warranty coverage for 
affected individuals. As a result, the FAA has included all known costs 
in the agency's 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.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to transport category airplanes and 
associated appliances to the Director of the System Oversight Division.

Regulatory Findings

    This AD will not have federalism implications under Executive Order

[[Page 64725]]

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.

Adoption of 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 (AD):

2019-22-06 The Boeing Company: Amendment 39-19785; Docket No. FAA-
2019-0323; Product Identifier 2019-NM-026-AD.

(a) Effective Date

    This AD is effective December 30, 2019.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-800 series 
airplanes, certificated in any category, line numbers 4919 through 
5063 inclusive, modified with split winglets per supplemental type 
certificate (STC) ST00830SE and listed in Aviation Partners Boeing 
Service Bulletin AP737-57-020, dated April 5, 2018.

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

    This AD was prompted by reports of inadequate clearance between 
a certain fuel quantity indicating system (FQIS) tank unit and a 
certain reinforcement angle added as a part of a certain split 
winglet modification. The FAA is issuing this AD to address this 
condition, which could result in a potential source of ignition in a 
fuel tank and consequent fire, overpressure, and structural failure 
of the wing and possible loss of the airplane.

(f) Compliance

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

(g) Inspection and Repair

    Within 18 months after the effective date of this AD: Perform a 
detailed inspection to determine the clearance between the FQIS tank 
unit at rib 21 (WSTA 617) and stringer U-14 reinforcement angle in 
accordance with the Accomplishment Instructions of Aviation Partners 
Boeing Service Bulletin AP737-57-020, dated April 5, 2018. If the 
measured clearance is less than 0.10 inch: Before further flight, 
perform the repair action in accordance with the Accomplishment 
Instructions of Aviation Partners Boeing Service Bulletin AP737-57-
020, dated April 5, 2018.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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 (i) of this AD. Information may be 
emailed to: [email protected].
    (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.

(i) Related Information

    For more information about this AD, contact Christopher Baker, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3552; email: [email protected].

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) 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) Aviation Partners Boeing Service Bulletin AP737-57-020, 
dated April 5, 2018.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
Aviation Partners Boeing, 2811 S 102nd Street, Suite 200, Seattle, 
WA 98168; telephone 206-830-7699; internet https://www.aviationpartnersboeing.com.
    (4) You may view this service information at the FAA, Transport 
Standards Branch, 2200 South 216th St., Des Moines, WA. For 
information on the availability of this material at the FAA, call 
206-231-3195.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Des Moines, Washington, on November 7, 2019.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-25474 Filed 11-22-19; 8:45 am]
 BILLING CODE 4910-13-P

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