Document ID: FAA-2020-0789-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2020-09-08T04:00Z

[Federal Register Volume 85, Number 174 (Tuesday, September 8, 2020)]
[Proposed Rules]
[Pages 55391-55395]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-19582]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0789; Project Identifier AD-2020-00849-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 supersede Airworthiness Directive (AD) 
2019-22-10, which applies to all The Boeing Company Model 737-600, -
700, -700C, -800, -900, and -900ER series airplanes. AD 2019-22-10 
requires repetitive inspections for cracking of the left- and right-
hand side outboard chords of frame fittings and failsafe straps at a 
certain station around eight fasteners, and repair if any cracking is 
found. Since the FAA issued AD 2019-22-10, it was determined that the 
initial inspection threshold and repetitive inspection interval are 
inadequate to address the cracking in a timely manner. For certain 
airplanes, this proposed AD would reduce the compliance time for the 
initial inspection, and for all airplanes this proposed AD would reduce 
the compliance time for the repetitive inspections. 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 October 23, 
2020.

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 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 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. 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. It is 
also available on the internet at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-0789.

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-2020-
0789; 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. Comments will be 
available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Greg Rutar, Aerospace Engineer, 
Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3529; email: 
Greg.Rutar@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to participate in this rulemaking by submitting 
written comments, data, or views about this proposal. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. To 
ensure the docket does not contain duplicate comments, commenters 
should submit only one copy of the comments. Send your comments to an 
address listed under the ADDRESSES section. Include ``Docket No.

[[Page 55392]]

FAA-2020-0789; Project Identifier AD-2020-00849-T'' at the beginning of 
your 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, as well 
as a report summarizing each substantive public contact with FAA 
personnel concerning this proposed rulemaking. Before acting on this 
proposal, the FAA will consider all comments received by the closing 
date for comments. The FAA will consider comments filed after the 
comment period has closed if it is possible to do so without incurring 
expense or delay. The FAA may change this NPRM because of those 
comments.

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 the 
person identified in the FOR FURTHER INFORMATION CONTACT section. Any 
commentary that the FAA receives which is not specifically designated 
as CBI will be placed in the public docket for this rulemaking.

Discussion

    The FAA issued AD 2019-22-10, Amendment 39-19789 (84 FR 61533, 
November 13, 2019) (``AD 2019-22-10''), for all The Boeing Company 
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. AD 
2019-22-10 requires inspections for cracking of the left- and right-
hand side outboard chords of frame fittings and failsafe straps at a 
certain station around eight fasteners, and repair if any cracking is 
found. AD 2019-22-10 superseded AD 2019-20-02 Amendment 39-19755 (84 FR 
52754, October 3, 2019) (``AD 2019-20-02''). AD 2019-22-10 resulted 
from reports of cracking discovered in the left- and right-hand side 
outboard chords of the station (STA) 663.75 frame fittings and failsafe 
straps adjacent to the stringer S-18A straps and a determination that 
the inspection area specified in AD 2019-20-02 needed to be expanded. 
The FAA issued AD 2019-22-10 to address cracking in the STA 663.75 
frame fitting outboard chords and failsafe straps adjacent to the 
stringer S-18A straps, which could result in failure of a Principal 
Structural Element (PSE) to sustain limit load. This condition could 
adversely affect the structural integrity of the airplane and result in 
loss of control of the airplane.

Actions Since AD 2019-22-10 Was Issued

    Since the FAA issued AD 2019-22-10, it was determined by an 
engineering analysis of the inspection reporting results and 
metallurgical evaluation of the submitted frame fitting assemblies that 
the initial inspection threshold for Model 737-900ER series airplanes, 
and the repetitive inspection interval for all affected airplanes is 
inadequate to address the cracking in a timely manner.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Multi-Operator Message MOM-MOM-20-0443-01B 
(R1), dated June 2, 2020. This service information describes procedures 
for repetitive detailed inspections for cracking of the left- and 
right-hand side outboard chords of the STA 663.75 frame fittings and 
failsafe straps around eight fasteners adjacent to the stringer S-18A 
straps.
    This proposed AD also requires Boeing Multi-Operator Message MOM-
MOM-19-0536-01B, dated September 30, 2019, which the Director of the 
Federal Register approved for incorporation by reference as of October 
3, 2019 (84 FR 52754, October 3, 2019).
    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.

FAA's Determination

    The FAA is proposing this AD because the agency evaluated all the 
relevant information and determined the unsafe condition described 
previously is likely to exist or develop in other products of the same 
type design.

Proposed AD Requirements

    This proposed AD requires repetitive inspections for cracking of 
the left- and right-hand side outboard chords of the STA 663.75 frame 
fittings and failsafe straps around eight fasteners adjacent to the 
stringer S-18A straps. This proposed AD also requires repair of all 
cracking using a method approved by the FAA or The Boeing Company 
Organization Designation Authorization (ODA). Accomplishing the initial 
inspection required by paragraph (i) of this proposed AD would 
terminate the inspections originally required by paragraph (g) of AD 
2019-22-10, which are retained in this proposed AD (the associated 
reporting specified in paragraph (h) of AD 2019-22-10 is also retained 
in this proposed AD). This proposed AD would also require sending a 
report of all results of the initial inspections specified in paragraph 
(i) of this proposed AD to Boeing.
    Although this proposed AD does not explicitly restate the 
requirements of paragraphs (i), (j), and (k) of AD 2019-22-10, this 
proposed AD would retain those requirements with certain revised 
compliance times. Those requirements are referenced in Boeing Multi-
Operator Message MOM-MOM-20-0443-01B (R1), dated June 2, 2020, which, 
in turn, is referenced in paragraphs (i) and (l) of this proposed AD.
    For information on the procedures and compliance times, see this 
service information at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2020-0789.

Explanation of New Compliance Times for Certain Configurations

    For Boeing Model 737-600, -700, -700C, -800, and -900 series 
airplanes having less than 22,600 total flight cycles and on which an 
inspection specified in Boeing Multi-Operator Message MOM-MOM-19-0623-
01B, dated November 5, 2019, has been done; and for Boeing Model 737-
900ER series airplanes having less than 14,000 total flight cycles and 
on which an inspection specified in Boeing Multi-Operator Message MOM-
MOM-19-0623-01B, dated November 5, 2019, has been done, the compliance 
times specified in Boeing Multi-Operator Message MOM-MOM-20-0443-01B 
(R1), dated June 2, 2020 (which will be required by this proposed AD), 
are relieving as compared to the compliance times in Boeing Multi-
Operator Message MOM-MOM-19-0623-01B, dated November 5, 2019 (which is 
required by AD 2019-22-10).
    For example, for a Boeing Model 737-600 series airplane on which 
the inspection was done and the airplane had accumulated 15,000 total 
flight cycles, the next inspection required by AD 2019-22-10 would be 
at 18,500 total flight cycles (i.e., 3,500 flight cycles after the 
inspection as specified in

[[Page 55393]]

Boeing Multi-Operator Message MOM-MOM-19-0623-01B, dated November 5, 
2019).
    However, as specified in Boeing Multi-Operator Message MOM-MOM-20-
0443-01B (R1), dated June 2, 2020, the next inspection for that 
airplane is prior to 22,600 total flight cycles or within 1,500 flight 
cycles from the last inspection in accordance with MOM-MOM-19-0623-01B, 
or within 30 days from the original issue date of MOM-MOM-20-0443-01B 
(R1) (which would correspond to 30 days after the effective date of the 
final rule for this proposed AD), whichever occurs latest.
    In conclusion, if the inspection was done early, operators do not 
have to do the next inspection at the 3,500 interval required by AD 
2019-22-10 after this proposed AD is a final rule; instead operators 
would then do the next inspection within the new compliance times 
specified in Boeing Multi-Operator Message MOM-MOM-20-0443-01B R1), 
dated June 2, 2020, for their configuration.

Interim Action

    The FAA considers this proposed AD interim action. The inspection 
reports that are required by this proposed AD will enable the 
manufacturer to obtain better insight into the nature, cause, and 
extent of the cracking, and eventually to develop final action to 
address the unsafe condition. Once final action has been identified, 
the FAA might consider further rulemaking.

Costs of Compliance

    The FAA estimates that this proposed AD affects 1,911 airplanes of 
U.S. registry. The FAA estimates the following costs to comply with 
this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost     Cost per  product        operators
----------------------------------------------------------------------------------------------------------------
Inspection (retained action from   1 work-hour x $85                $0  $85 per inspection   $162,435 per
 AD 2019-22-10).                    per hour = $85 per                   cycle.               inspection cycle.
                                    inspection cycle.
Reporting (retained action from    1 work-hour x $85                 0  85.................  162,435.
 AD 2019-22-10).                    per hour = $85.
Inspection (new action)..........  1 work-hour(s) x                  0  85 per inspection    162,435 per
                                    $85 per hour = $85                   cycle.               inspection cycle.
                                    per inspection
                                    cycle.
Reporting (new action)...........  1 work-hour x $85                 0  85.................  162,435.
                                    per hour = $85.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data that would enable the 
agency to provide cost estimates for the on-condition actions specified 
in this proposed AD.

Paperwork Reduction Act

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to penalty for 
failure to comply with a collection of information subject to the 
requirements of the Paperwork Reduction Act unless that collection of 
information displays a current valid OMB control number. The control 
number for the collection of information required by this proposed AD 
is 2120-0056. The paperwork cost associated with this proposed AD has 
been detailed in the Costs of Compliance section of this document and 
includes time for reviewing instructions, as well as completing and 
reviewing the collection of information. Therefore, all reporting 
associated with this proposed AD is mandatory. Comments concerning the 
accuracy of this burden and suggestions for reducing the burden should 
be directed to Information Collection Clearance Officer, Federal 
Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-
1524.

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 has 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 that the proposed 
regulation:
    (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 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 removing Airworthiness Directive (AD) 
2019-22-10, Amendment 39-19789 (84 FR 61533, November 13, 2019), and 
adding the following new AD:

The Boeing Company: Docket No. FAA-2020-0789; Project Identifier AD-
2020-00849-T.

(a) Comments Due Date

    The FAA must receive comments on this AD action by October 23, 
2020.

[[Page 55394]]

(b) Affected ADs

    This AD replaces AD 2019-22-10, Amendment 39-19789 (84 FR 61533, 
November 13, 2019) (``AD 2019-22-10'').

(c) Applicability

    This AD applies to all The Boeing Company Model 737-600, -700, -
700C, -800, -900, and -900ER series airplanes, certificated in any 
category.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by reports of cracking discovered in the 
station (STA) 663.75 frame fitting outboard chords and failsafe 
straps adjacent to the stringer S-18A straps and a determination 
that the initial inspection threshold for certain airplanes and the 
repetitive inspection interval specified in AD 2019-22-10 are 
inadequate to address the cracking in a timely manner. The FAA is 
issuing this AD to address cracking in the STA 663.75 frame fitting 
outboard chords and failsafe straps adjacent to the stringer S-18A 
straps, which could result in failure of a Principal Structural 
Element (PSE) to sustain limit load. This condition could adversely 
affect the structural integrity of the airplane and result in loss 
of control of the airplane.

(f) Compliance

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

(g) Retained Inspection and Corrective Action With No Changes

    This paragraph restates the requirements of paragraph (g) of AD 
2019-22-10 with no changes. At the earlier of the times specified in 
paragraphs (g)(1) and (2) of this AD: Do a detailed inspection for 
cracking of the left- and right-hand side outboard chords of the STA 
663.75 frame fittings and failsafe straps adjacent to the stringer 
S-18A straps, in accordance with Boeing Multi-Operator Message MOM-
MOM-19-0536-01B, dated September 30, 2019. If any crack is found, 
repair before further flight using a method approved in accordance 
with the procedures specified in paragraph (n) of this AD. Repeat 
the inspection thereafter at intervals not to exceed 3,500 flight 
cycles until the initial inspection required by paragraph (i) of 
this AD is done.
    (1) Prior to the accumulation of 30,000 total flight cycles, or 
within 7 days after October 3, 2019 (the effective date of AD 2019-
20-02, Amendment 39 19755 (84 FR 52754, October 3, 2019) (``AD 2019-
20-02'')), whichever occurs later.
    (2) Prior to the accumulation of 22,600 total flight cycles, or 
within 1,000 flight cycles after October 3, 2019 (the effective date 
of AD 2019-20-02), whichever occurs later.

(h) Retained Reporting Requirement With No Changes

    This paragraph restates the requirements of paragraph (h) of AD 
2019-22-10, with no changes. At the applicable time specified in 
paragraph (h)(1) or (2) of this AD, submit a report of all findings, 
positive and negative, of the initial inspection required by 
paragraph (g) of this AD. Submit the report in accordance with 
Boeing Multi-Operator Message MOM-MOM-19-0536-01B, dated September 
30, 2019.
    (1) If the inspection was done on or after October 3, 3019 (the 
effective date of AD 2019-20-02): Submit the report within 3 days 
after the inspection.
    (2) If the inspection was done before October 3, 2019 (the 
effective date of AD 2019-20-02): Submit the report within 3 days 
after October 3, 2019.

(i) Inspection and Corrective Action With Reduced Compliance Times

    Except as specified in paragraph (j) of this AD: At the 
applicable initial compliance time specified in Tables 1 and 2 of 
``Ref I'' of Boeing Multi-Operator Message MOM-MOM-20-0443-01B (R1), 
dated June 2, 2020, do a detailed inspection of the left- and right-
hand side outboard chords of the STA 663.75 frame fittings and 
failsafe straps around eight fasteners adjacent to the stringer S-
18A straps, in accordance with Boeing Multi-Operator Message MOM-
MOM-20-0443-01B (R1), dated June 2, 2020. If any crack is found, 
repair before further flight using a method approved in accordance 
with the procedures specified in paragraph (n) of this AD. Repeat 
the inspection thereafter at the applicable intervals specified in 
Tables 1 and 2 of ``Ref I'' of Boeing Multi-Operator Message MOM-
MOM-20-0443-01B (R1), dated June 2, 2020. Accomplishing the initial 
inspection required by this paragraph or an initial inspection 
specified in Boeing Multi-Operator Message MOM-MOM-19-0623-01B, 
dated November 5, 2019, terminates the inspections required by 
paragraph (g) of this AD.

(j) Exceptions to Service Information Specifications

    Where Boeing Multi-Operator Message MOM-MOM-20-0443-01B (R1), 
dated June 2, 2020, uses the phrase ``the original issue date of 
MOM-MOM-20-0443-01B(R1),'' this AD requires using ``the effective 
date of this AD.''

(k) New Reporting Requirement

    At the applicable time specified in paragraph (k)(1) or (2) of 
this AD, submit a report of all findings, positive and negative, of 
the initial inspection required by paragraph (i) of this AD. Submit 
the report in accordance with MOM-MOM-20-0443-01B (R1), dated June 
2, 2020.
    (1) If the inspection was done on or after the effective date of 
this AD: Submit the report within 3 days after the inspection.
    (2) If the inspection was done before the effective date of this 
AD: Submit the report within 3 days after the effective date of this 
AD.

(l) Special Flight Permit

    Special flight permits may be issued in accordance with 14 CFR 
21.197 and 21.199 to operate the airplane to a location where the 
airplane can be repaired if any crack is found, provided the 
Manager, Seattle ACO Branch, FAA, concurs with issuance of the 
special flight permit. Send requests for concurrence by email to 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.

(m) Paperwork Reduction Act Burden Statement

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to a penalty 
for failure to comply with a collection of information subject to 
the requirements of the Paperwork Reduction Act unless that 
collection of information displays a current valid OMB Control 
Number. The OMB Control Number for this information collection is 
2120-0056. Public reporting for this collection of information is 
estimated to be approximately 1 hour per response, including the 
time for reviewing instructions, searching existing data sources, 
gathering and maintaining the data needed, and completing and 
reviewing the collection of information. All responses to this 
collection of information are mandatory as required by this AD. Send 
comments regarding this burden estimate or any other aspect of this 
collection of information, including suggestions for reducing this 
burden to Information Collection Clearance Officer, Federal Aviation 
Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524.

(n) 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 (o)(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.
    (4) AMOCs approved previously for AD 2019-20-02 are approved as 
AMOCs for the corresponding provisions of this AD.
    (5) AMOCs approved previously for AD 2019-22-10 are approved as 
AMOCs for the corresponding provisions of this AD.

(o) Related Information

    (1) For more information about this AD, contact Greg Rutar, 
Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 
South 216th St., Des Moines, WA

[[Page 55395]]

98198; phone and fax: 206-231-3529; email: Greg.Rutar@faa.gov.
    (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 https://www.myboeingfleet.com.

    Issued on August 26, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-19582 Filed 9-4-20; 8:45 am]
BILLING CODE 4910-13-P