[Federal Register Volume 87, Number 142 (Tuesday, July 26, 2022)]
[Proposed Rules]
[Pages 44285-44288]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-15848]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0810; Project Identifier AD-2021-01238-T]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company 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 all The Boeing Company Model 777 airplanes. This proposed AD was 
prompted by fuel system reviews conducted by the manufacturer. This 
proposed AD would require, depending on the airplane configuration, 
installation of Teflon sleeves, cap sealing of fasteners, detailed 
inspections, and corrective actions. This proposed AD would also 
require revising the existing maintenance or inspection program, as 
applicable, to incorporate more restrictive airworthiness limitations 
(AWLs). 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 September 
9, 2022.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to 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 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 www.myboeingfleet.com. 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. Boeing Alert Service Bulletin 777-57A0050, Revision 6, dated 
August 18, 2021, is also available at www.regulations.gov by searching 
for and locating Docket No. FAA-2022-0810.

Examining the AD Docket

    You may examine the AD docket at www.regulations.gov by searching 
for and locating Docket No. FAA-2022-0810; 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: Kevin Nguyen, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3555; email: 
[email protected].

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-2022-0810; Project Identifier 
AD-2021-01238-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 
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 Kevin 
Nguyen, Aerospace Engineer, Propulsion Section, FAA, Seattle ACO 
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-
231-3555; email: [email protected]. Any commentary that the FAA 
receives that is not specifically designated as CBI will be placed in 
the public docket for this rulemaking.

Background

    The FAA has examined the underlying safety issues involved in fuel 
tank explosions on several large transport airplanes, including the 
adequacy of existing regulations, the service history of airplanes 
subject to those regulations, and existing maintenance practices for 
fuel tank systems. As a result of those findings, the FAA issued a 
regulation titled ``Transport Airplane Fuel Tank System Design Review, 
Flammability Reduction and Maintenance and Inspection Requirements'' 
(66 FR 23086, May 7, 2001). In addition to new airworthiness standards 
for transport airplanes and new maintenance requirements, this rule 
included Special Federal Aviation Regulation No. 88 (SFAR 88), 
Amendment 21-78. Subsequently, SFAR 88 was amended by Amendment 21-82 
(67 FR 57490, September 10, 2002; corrected at 67 FR 70809, November 
26, 2002) and Amendment 21-83 (67 FR 72830, December 9, 2002; corrected 
at 68 FR 37735, June 25, 2003, to change ``21-82'' to ``21-83'').
    Among other actions, SFAR 88 requires certain type design (i.e., 
type certificate (TC) and supplemental type certificate (STC)) holders 
to substantiate that their fuel tank systems can prevent ignition 
sources in the fuel tanks. This requirement applies to type design 
holders for large turbine-powered

[[Page 44286]]

transport airplanes and for subsequent modifications to those 
airplanes. It requires them to perform design reviews and to develop 
design changes and maintenance procedures if their designs do not meet 
the new fuel tank safety standards. As explained in the preamble to the 
rule, the FAA intended to adopt airworthiness directives to mandate any 
changes found necessary to address unsafe conditions identified as a 
result of these reviews.
    In evaluating these design reviews, the FAA has established four 
criteria intended to define the unsafe conditions associated with fuel 
tank systems that require corrective actions. The percentage of 
operating time during which fuel tanks are exposed to flammable 
conditions is one of these criteria. The other three criteria address 
the failure types under evaluation: Single failures, combination of 
failures, and unacceptable (failure) experience. For all three failure 
criteria, the evaluations included consideration of previous actions 
taken that may mitigate the need for further action.
    The FAA has determined that the actions identified in this proposed 
AD are necessary to reduce the potential of ignition sources inside 
fuel tanks, which, in combination with flammable fuel vapors, could 
result in fuel tank explosions and consequent loss of the airplane.
    The FAA issued AD 2017-11-14, Amendment 39-18913 (82 FR 25954, June 
6, 2017) (AD 2017-11-14), for certain The Boeing Company Model 777-200, 
-200LR, -300, and -300ER series airplanes, to prevent arcing inside the 
main and center fuel tanks in the event of a fault current or lightning 
strike, which, in combination with flammable fuel vapors, could result 
in a fuel tank explosion and consequent loss of the airplane.
    AD 2017-11-14 requires certain inspections for certain airplanes, 
corrective actions if necessary, and installation of Teflon sleeves 
under certain wire bundle clamps.
    Since the FAA issued AD 2017-11-14, it was discovered that more 
airplanes are affected by the identified unsafe condition, and 
additional work is required for airplanes on which an earlier revision 
of the service information was done.

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 Boeing Alert Service Bulletin 777-57A0050, 
Revision 6, dated August 18, 2021. This service information specifies 
applicable actions that vary depending on the airplane configuration, 
such as procedures for the installation of Teflon sleeves, cap sealing 
of fasteners, detailed inspections, and corrective actions. The 
detailed inspection of and installation of Teflon sleeves includes 
various locations, such as the rear spar wire bundles, inboard and 
outboard front spar wire bundles, wing-to-body fairing and 
environmental control system (ECS) bay wire bundles, front and rear 
spar bulkhead wire bundles, and wing rear spar wire bundles. The 
detailed inspection of and cap sealing of fasteners include fasteners 
in the center fuel tank, left and right main fuel tanks, and right 
cheek portion of the center fuel tank. Corrective actions include 
installing Teflon sleeve, installing clamp, and cap sealing fasteners.
    The FAA also reviewed Section 9, Airworthiness Limitations (AWLs) 
and Certification Maintenance Requirements (CMRs), D622W001-9, dated 
March 2022, of Boeing 777 200/200LR/300/300ER/777F Maintenance Planning 
Data (MPD) Document. This service information specifies, among other 
airworthiness limitations, 28-AWL-31 and 28-AWL-32 that address cushion 
clamps and Teflon sleeving installed on out-of-tank wire bundles 
installed on brackets that are mounted directly on the fuel tanks.
    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.

Proposed AD Requirements in This NPRM

    This proposed AD would require doing all applicable actions (i.e., 
installation of Teflon sleeves, cap sealing of fasteners, detailed 
inspections, and corrective actions) identified in Boeing Alert Service 
Bulletin 777-57A0050, Revision 6, dated August 18, 2021. This proposed 
AD would also require revising the existing maintenance or inspection 
program, as applicable, to incorporate AWLs 28-AWL-31 and 28-AWL-32 as 
identified in Section 9, Airworthiness Limitations (AWLs) and 
Certification Maintenance Requirements (CMRs), D622W001-9, dated March 
2022. For information on the procedures and compliance times for the 
applicable actions specified in paragraph (g) of this AD, see Boeing 
Alert Service Bulletin 777-57A0050, Revision 6, dated August 18, 2021, 
at www.regulations.gov by searching for and locating Docket No. FAA-
2022-0810.
    This proposed AD would require revisions to certain operator 
maintenance documents to include new actions (e.g., inspections) and 
Critical Design Configuration Control Limitations (CDCCLs). Compliance 
with these actions and CDCCLs is required by 14 CFR 91.403(c). For 
airplanes that have been previously modified, altered, or repaired in 
the areas addressed by this proposed AD, the operator may not be able 
to accomplish the actions described in the revisions. In this 
situation, to comply with 14 CFR 91.403(c), the operator must request 
approval for an alternative method of compliance according to paragraph 
(m) of this proposed AD.
    This NPRM would not supersede AD 2017-11-14. Rather, the FAA has 
determined that a stand-alone AD would be more appropriate to address 
the changes. Accomplishment of the actions required by paragraph (g) of 
this proposed AD would then terminate the requirements of paragraphs 
(g)(1), (i), and (j) of AD 2017-11-14.
    In addition, accomplishment of the revision required by paragraph 
(i) of this proposed AD would terminate the requirements of paragraphs 
(g)(6) and (h) of AD 2021-24-12, Amendment 39-21833 (86 FR 73660, 
December 28, 2021) (AD 2021-24-12). AD 2021-24-12 requires revising the 
existing maintenance or inspection program, as applicable, to 
incorporate multiple AWLs, including 28-AWL-31 and 28-AWL-32.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 282 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

[[Page 44287]]



                                                Estimated Costs *
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                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
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Installations, cap sealing, and   Up to 545 work-     Up to $3,510......  Up to $49,835.....  Up to $14,053,470.
 inspections.                      hours x $85 per
                                   hour = $46,325.
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* Table does not include estimated costs for revising the existing maintenance or inspection program.

    The FAA has determined that revising the existing maintenance or 
inspection program takes an average of 90 work-hours per operator, 
although the agency recognizes that this number may vary from operator 
to operator. Since operators incorporate maintenance or inspection 
program changes for their affected fleet(s), the FAA has determined 
that a per-operator estimate is more accurate than a per-airplane 
estimate. Therefore, the FAA estimates the average total cost per 
operator to be $7,650 (90 work-hours x $85 per work-hour).
    The FAA estimates the following costs to do any necessary 
corrective actions that would be required based on the results of the 
proposed inspections. The agency has no way of determining the number 
of aircraft that might need these actions:

                                               On-Condition Costs
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                Action                        Labor cost               Parts cost            Cost per product
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Corrective actions...................  Up to 26 work-hours x    Up to $3,510...........  Up to $5,720.
                                        $85 per hour = $2,210.
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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:

The Boeing Company: Docket No. FAA-2022-0810; Project Identifier AD-
2021-01238-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 9, 2022.

(b) Affected ADs

    (1) This AD affects AD 2017-11-14, Amendment 39-18913 (82 FR 
25954, June 6, 2017) (AD 2017-11-14).
    (2) This AD also affects AD 2021-24-12, Amendment 39-21833 (86 
FR 73660, December 28, 2021) (AD 2021-24-12).

(c) Applicability

    This AD applies to all The Boeing Company Model 777-200, -200LR, 
-300, -300ER, and 777F series airplanes, certificated in any 
category.

(d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by fuel system reviews conducted by the 
manufacturer. The FAA is issuing this AD to prevent arcing inside 
the main and center fuel tanks in the event of a fault current or 
lightning strike, which, in combination with flammable fuel vapors, 
could result in a fuel tank explosion and consequent loss of the 
airplane.

(f) Compliance

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

(g) Required Service Bulletin Actions

    For airplanes identified in Boeing Alert Service Bulletin 777-
57A0050, Revision 6, dated August 18, 2021: Except as specified in 
paragraph (h) of this AD, at the applicable times specified in 
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
777-57A0050, Revision 6, dated August 18, 2021, do all applicable 
actions (i.e., installation of Teflon sleeves, cap sealing of 
fasteners, detailed inspections, and corrective actions) identified 
in, and in accordance with, the Accomplishment Instructions of 
Boeing Alert Service Bulletin 777-57A0050, Revision 6, dated August 
18, 2021. Do all applicable corrective actions before further 
flight.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 777-57A0050, Revision 6, 
dated August 18, 2021, uses the phrase ``the revision 5 date of

[[Page 44288]]

this service bulletin'' or ``the revision 6 date of this service 
bulletin,'' this AD requires using ``the effective date of this 
AD.''
    (2) Where circle symbol 1 of sheet 2 of Figures 172, 173, and 
174 of Boeing Alert Service Bulletin 777-57A0050, Revision 6, dated 
August 18, 2021, points to the outboard side of rib no. 9 for the 
locate and cap seal task or the inspection task, as applicable, in 
step 1 of sheet 3, for this AD, circle symbol 1 points to the seven 
fasteners located at the inboard side of rib no. 9.
    (3) Where circle symbol 1, next to the text ``7 locations,'' of 
sheet 2 of Figure 175 and Figure 176 of Boeing Alert Service 
Bulletin 777-57A0050, Revision 6, dated August 18, 2021, points to 
the outboard side of rib no. 9 for the locate and cap seal task or 
the inspection task, as applicable, in step 1 of sheet 3, for this 
AD, circle symbol 1, next to the text ``7 locations,'' points to the 
seven fasteners located at the inboard side of rib no. 9.
    (4) Where circle symbol 1, next to the text ``7 locations,'' of 
sheet 4 of Figure 179 and Figure 180 of Boeing Alert Service 
Bulletin 777-57A0050, Revision 6, dated August 18, 2021, points to 
the outboard side of rib no. 9 for the locate and cap seal task or 
the inspection task, as applicable, in step 1 of sheet 6, for this 
AD, circle symbol 1, next to the text ``7 locations,'' points to the 
seven fasteners located at the inboard side of rib no. 9.

(i) Maintenance or Inspection Program Revision

    Within 60 days after the effective date of this AD, revise the 
existing maintenance or inspection program, as applicable, to 
incorporate the information for 28-AWL-31 and 28-AWL-32 specified in 
Section D, ``Airworthiness Limitations-Systems,'' including 
Subsections D.1, of Section 9, Airworthiness Limitations (AWLs) and 
Certification Maintenance Requirements (CMRs), D622W001-9, dated 
March 2022, of Boeing 777-200/200LR/300/300ER/777F Maintenance 
Planning Data (MPD) Document, except as specified in paragraph (j) 
of this AD. The initial compliance time for doing airworthiness 
limitation instructions (ALI) task 28-AWL-32 is at the applicable 
time specified in paragraph (i)(1) or (2) of this AD:
    (1) For airplanes having line numbers (L/Ns) 1 through 503 
inclusive: Within 3,750 days after accomplishment of the actions 
specified in Boeing Service Bulletin 777-57A0050, or within 60 
months after the effective date of this AD, whichever occurs later.
    (2) For airplanes having L/Ns 504 and subsequent: Within 3,750 
days after the date of issuance of the original airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness; or within 60 months after the 
effective date of this AD; whichever occurs later.

(j) Exceptions to the AWLs

    The following exceptions apply to 28-AWL-31 and 28-AWL-32 of 
Section D, ``Airworthiness Limitations--Systems,'' including 
Subsections D.1 of Section 9, Airworthiness Limitations (AWLs) and 
Certification Maintenance Requirements (CMRs), D622W001-9, dated 
March 2022, of Boeing 777-200/200LR/300/300ER/777F Maintenance 
Planning Data (MPD) Document.
    (1) In paragraph 1.i., change ``Front Spar Bulkhead (Center 
Tank)'' to ``Front Spar Bulkhead (Center Wing Tank Fuel Quantity 
Greater than 12,400 Gallons).''
    (2) In paragraph 1.i.II, change ``For 777-200, 777-200LR, 777-
300, and 777-300ER airplanes, L/N 562 and on'' to ``L/N 562 and on, 
except 777F.''
    (3) In paragraph 1.i.III., change ``For 777F airplanes, L/N 718 
and on'' to ``For 777F airplanes.''
    (4) In paragraph 1.j., change ``Rear Spar Bulkhead (Center 
Tank)'' to ``Rear Spar Bulkhead (Center Wing Tank Fuel Quantity 
Greater than 12,400 Gallons).''

(k) No Alternative Actions, Intervals, or Critical Design Configuration 
Control Limitations (CDCCLs)

    After the existing maintenance or inspection program has been 
revised as required by paragraph (i) of this AD, no alternative 
actions (e.g., inspections), intervals, or CDCCLs may be used unless 
the actions, intervals, and CDCCLs are approved as an alternative 
method of compliance (AMOC) in accordance with the procedures 
specified in paragraph (m) of this AD.

(l) Terminating Action for Certain Requirements of AD 2017-11-14 and AD 
2021-24-12

    (1) Accomplishment of the actions required by paragraph (g) of 
this AD terminates the requirements of paragraphs (g)(1), (i), and 
(j) of AD 2017-11-14.
    (2) Accomplishment of the revision required by paragraph (i) of 
this AD terminates the requirements of paragraphs (g)(6) and (h) of 
AD 2021-24-12.

(m) 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 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 (n)(1) 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 responsible Flight Standards 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.

(n) Related Information

    (1) For more information about this AD, contact Kevin Nguyen, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3555; email: [email protected].
    (2) For service information identified in this AD, 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 www.myboeingfleet.com. You 
may view this referenced 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.

    Issued on June 30, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-15848 Filed 7-25-22; 8:45 am]
BILLING CODE 4910-13-P