[Federal Register Volume 85, Number 61 (Monday, March 30, 2020)]
[Rules and Regulations]
[Pages 17480-17483]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-06459]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0719; Product Identifier 2019-NM-137-AD; Amendment 
39-19876; AD 2020-05-26]
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

[[Page 17481]]

The Boeing Company Model 787-8 airplanes. This AD was prompted by a 
report of failure of a wing strut leak test due to a missing bolt on 
the firewall. This AD requires a one-time leak test of the strut upper 
spar areas for the left and right wing struts, and corrective action if 
necessary. The FAA is issuing this AD to address the unsafe condition 
on these products.

DATES: This AD is effective May 4, 2020.

ADDRESSES: For service information identified in this final rule, 
contact Boeing Commercial Airplanes, Attention: Contractual & Data 
Services (C&DS), 2600 Westminster Blvd., MC 110 SK57, Seal Beach, CA 
90740-5600; telephone 562-797-1717; internet https://www.myboeingfleet.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.

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-
0719; 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: Tak Kobayashi, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3553; email: 
takahisa.kobayashi@faa.gov.

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 787-8 airplanes. The NPRM published in the Federal 
Register on November 1, 2019 (84 FR 58636). The NPRM was prompted by a 
report of failure of a wing strut leak test due to a missing bolt on 
the firewall. The NPRM proposed to require a one-time leak test of the 
strut upper spar areas for the left and right wing struts, and 
corrective action if necessary.
    The FAA is issuing this AD to address a hole in the firewall, which 
could allow flammable fluid to leak from the strut compartment to the 
engine compartment when the drainage provision is overwhelmed. 
Flammable fluid leakage into the engine compartment could result in an 
uncontrollable engine fire and consequent structural failure of the 
wing.

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

    Two commenters, Patrick Imperatrice and Seth Stewart, indicated 
support for the NPRM.

Request To Change the Unsafe Condition

    Boeing asked that the current language for the unsafe condition 
specified in the proposed AD, which states, in part, ``. . . which 
could allow flammable fluid leakage in the strut area. This leakage 
could overwhelm the drainage provision, enter the engine compartment . 
. .'' be changed to ``. . . which could allow flammable fluid to leak 
from the strut compartment to the engine core compartment . . . .'' 
Boeing stated that the hole in the firewall due to a missing bolt does 
not affect the drain provision from the strut system tubing shroud. 
Boeing added that a missing bolt does create an unintended drain path 
from the strut flammable fluid compartment to the engine core 
compartment fire zone.
    The FAA agrees with the commenter's request for the reason 
provided. The FAA has revised the Discussion section and paragraph (e) 
of this AD to include the suggested language.

Request To Clarify Certain Language

    Boeing asked that the language specified in paragraph (g)(2) of the 
proposed AD, be changed from ``strut upper spar (strut areas . . .)'' 
to ``systems tubing shroud (area . . .).'' Boeing stated that the water 
must be applied in the systems tubing shroud, not to the strut upper 
spar. Boeing added that the strut upper spar between the forward and 
mid-vapor barriers is a dry bay, but the systems tubing shroud is a 
flammable leakage zone.
    The FAA agrees with the commenter's request to clarify the language 
to be consistent with Boeing's terminology. This procedure is also 
provided in the Boeing 787 Aircraft Maintenance Manual (AMM), specified 
as additional guidance in this AD. The FAA has revised paragraph (g)(2) 
of this AD as suggested by the commenter.

Request To Remove Leak Test Requirement

    Boeing asked that the FAA remove the leak test required by 
paragraph (g) of the proposed AD and either require or include an 
option for a visual inspection for proper installation of the bolt on 
the firewall, as specified in planned Boeing Service Bulletin 787-
54A0021-I001. Boeing stated that paragraph (e) of the proposed AD 
specified that the unsafe condition was caused by a missing bolt that 
plugs a penetration on the strut firewall. Boeing added that a visual 
inspection done using the planned Boeing service information will 
verify the proper installation of the bolt, and ensure firewall 
integrity, in addition to less maintenance time than a leak test, 
resulting in lower costs for the airlines. Boeing also stated that the 
service bulletin is scheduled for release in June 2020, and will 
include instructions to inspect for a missing bolt, as well as 
corrective action to correctly install a missing bolt and perform a 
leak test to ensure proper drainage.
    The FAA acknowledges the commenter's request, but does not agree to 
revise this AD. The leak test required by this AD provides a practical 
means to address the unsafe condition, and this method is adequate 
since the service information is not yet approved or available. The FAA 
may not require any document that does not yet exist in an AD. In 
general terms, the FAA is required by Office of the Federal Register 
(OFR) regulations for approval of materials incorporated by reference, 
as specified in 1 CFR 51.1(f), to either publish the service document 
contents as part of the actual AD language; or submit the service 
document to the OFR for approval as referenced material, in which case 
the FAA may only refer to such material in the text of an AD. Since no 
service information for the visual inspection has been provided to the 
FAA, the agency is unable to evaluate or approve an inspection method. 
The FAA finds that delaying this action is inappropriate in light of 
the identified unsafe condition. If service information for this 
inspection becomes available later, it may be submitted to the FAA for 
approval of an alternative method of compliance under the provisions of 
paragraph (h) of this AD. The FAA has not changed this AD in this 
regard.

Request To Clarify a Procedure

    Boeing asked that the FAA add the language ``remove the tubing 
shroud cover'' to the end of paragraph (g)(1) of

[[Page 17482]]

the proposed AD to clarify the procedure. Boeing stated that if the 
tubing shroud cover is not removed, water cannot be poured into the 
systems tubing and side shroud areas.
    The FAA partially agrees with the commenter's request. The FAA 
determined that only the steps necessary for properly accomplishing the 
leak test--not the general steps necessary to prepare for the test--are 
included in the AD requirements. For additional guidance, Note 1 to 
paragraph (g) of this AD provides information related to the procedures 
in the applicable section of the Boeing 787 AMM. That section includes 
all relevant general steps for accomplishing the required leak test. 
Therefore, the FAA has not changed this AD in this regard.

Request for Correction of a Paragraph Identifier

    Boeing stated that there are two paragraph identifiers that are 
identical. Boeing noted that paragraph identifier (g)(5)(ii) of the 
proposed AD is repeated, and the second paragraph identifier should be 
(g)(5)(iii).
    The FAA agrees with the commenter and has corrected the paragraph 
identifier 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:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
     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.

Costs of Compliance

    The FAA estimates that this AD affects 2 airplanes of U.S. 
registry. The agency estimates the following costs to comply with this 
AD:

                                      Estimated Costs for Required Actions
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                                                                                    Cost per       Cost on U.S.
                          Labor cost                              Parts cost        product         operators
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3 work-hours x $85 per hour = $255...........................              $0             $255             $510
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    The FAA estimates the following costs to do any necessary on-
condition action that would be required based on the results of any 
required actions. The FAA has no way of determining the number of 
aircraft that might need this on-condition action:

                 Estimated Costs of On-Condition Action
------------------------------------------------------------------------
                                                             Cost per
            Labor cost                   Parts cost           product
------------------------------------------------------------------------
1 work-hour x $85 per hour = $85..  Minimal.............             $85
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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

    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.

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):

2020-05-26 The Boeing Company: Amendment 39-19876; Docket No. FAA-
2019-0719; Product Identifier 2019-NM-137-AD.

(a) Effective Date

    This AD is effective May 4, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 787-8 airplanes, 
certificated in any category, line numbers 6, 11, 17, 19, 20, 21, 
23, 25 through 30 inclusive, and 32 through 38 inclusive.

[[Page 17483]]

(d) Subject

    Air Transport Association (ATA) of America Code 54, Nacelles/
Pylons.

(e) Unsafe Condition

    This AD was prompted by a report of failure of a wing strut leak 
test due to a missing bolt on the firewall. The FAA is issuing this 
AD to address a hole in the firewall, which could allow flammable 
fluid to leak from the strut compartment to the engine compartment 
when the drainage provision is overwhelmed. Flammable fluid leakage 
into the engine compartment could result in an uncontrollable engine 
fire and consequent structural failure of the wing.

(f) Compliance

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

(g) Leak Test and Corrective Action

    Within 12 months after the effective date of this AD: Do a one-
time leak (functional) test of the strut upper spar areas for the 
left and right wing struts, by doing the actions specified in 
paragraphs (g)(1) through (5) of this AD. A review of airplane 
maintenance records is acceptable in lieu of this test if it can be 
conclusively determined from that review that the leak test was 
previously accomplished and successfully completed.
    (1) Put a plug in the strut forward drain outlet (this drain 
outlet is labeled as ``pylon strut''). Put an empty container below 
the strut forward drain outlet to collect water drained through this 
outlet.
    (2) Apply 381 to 387 fluid ounces (11.3 to 11.4 liters) of water 
in 2.5 to 3.5 minutes, to the systems tubing shroud (area between 
the forward and mid-vapor barriers).
    (3) Make sure that no leakage occurred after doing the action 
specified in paragraph (g)(2) of this AD.
    (4) Remove the plug from the strut forward drain outlet and make 
sure that the water is drained through the strut forward drain 
outlet only.
    (5) After 3 minutes from accomplishing the action specified in 
paragraph (g)(4) of this AD, measure the water collected in the 
container, and do the applicable actions specified in paragraphs 
(g)(5)(i) through (iii) of this AD.
    (i) If leaks were found, do corrective action before further 
flight using a method approved in accordance with the procedures 
specified in paragraph (h) of this AD.
    (ii) If no leaks were found and less than 354 fluid ounces (10.5 
liters) of water is collected in the container, do corrective action 
before further flight using a method approved in accordance with the 
procedures specified in paragraph (h) of this AD.
    (iii) Before further flight after accomplishing any corrective 
action required by paragraph (g)(5)(i) or (ii) of this AD, repeat 
the actions specified in paragraphs (g)(1) through (5) of this AD 
until successful completion of the test (i.e., no leaks are found 
and 354 fluid ounces (10.5 liters) of water or more is measured in 
the container).
    Note 1 to paragraph (g): Additional guidance for performing the 
leak (functional) test can be found in Boeing 787 Aircraft 
Maintenance Manual (AMM), 54-65-01, Strut Spar--Upper--Functional 
Test.

(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)(1) of this AD. Information may be 
emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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 The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Seattle 
ACO Branch, FAA, to make those findings. To be approved, the repair 
method, modification deviation, or alteration deviation must meet 
the certification basis of the airplane, and the approval must 
specifically refer to this AD.

(i) Related Information

    (1) For more information about this AD, contact Tak Kobayashi, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3553; email: takahisa.kobayashi@faa.gov.
    (2) For service information identified in this AD that is not 
incorporated by reference, contact Boeing Commercial Airplanes, 
Attention: Contractual & Data Services (C&DS), 2600 Westminster 
Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-
1717; internet https://www.myboeingfleet.com. For information on the 
availability of this material at the FAA, call 206-231-3195.

(j) Material Incorporated by Reference

    None.

    Issued on March 10, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-06459 Filed 3-27-20; 8:45 am]
 BILLING CODE 4910-13-P


