Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 88, Number 145 (Monday, July 31, 2023)]
[Rules and Regulations]
[Pages 49284-49287]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-16121]



[[Page 49284]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1479; Project Identifier AD-2022-00703-T; 
Amendment 39-22497; AD 2023-13-12]
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 all 
The Boeing Company Model 737-100, 737-200, 737-200C, 737-300, 737-400, 
737-500, 737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER, 757-
200, 757-200PF, 757-200CB, 757-300, 767-200, 767-300, 767-300F, and 
767-400ER series airplanes. This AD was prompted by reports indicating 
premature aging of certain passenger chemical oxygen generators. This 
AD requires repetitively replacing affected chemical oxygen generators 
with serviceable parts. This AD also limits the installation of 
affected parts. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective September 5, 2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2022-1479; 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: Nicole S. Tsang, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3959; 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 all The Boeing Company 
Model 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500, 737-600, 
737-700, 737-700C, 737-800, 737-900, 737-900ER, 757-200, 757-200PF, 
757-200CB, 757-300, 767-200, 767-300, 767-300F, and 767-400ER series 
airplanes. The NPRM published in the Federal Register on December 9, 
2022 (87 FR 75528).
    The NPRM was prompted by reports indicating premature aging of 
certain passenger chemical oxygen generators. In the NPRM, the FAA 
proposed to require repetitively replacing affected chemical oxygen 
generators with serviceable parts, and to limit the installation of 
affected parts. The FAA is issuing this AD to address the premature 
aging that resulted in the chemical oxygen generators failing to 
activate, which could fail to deliver oxygen during an emergency, 
possibly resulting in injury to the airplane occupants.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from the Air Line Pilots Association, 
International, and The Boeing Company. Both commenters supported the 
NPRM without change.
    The FAA received additional comments from Delta Air Lines, American 
Airlines, United Airlines, and United Parcel Service. The following 
presents the comments received on the NPRM and the FAA's response to 
each comment.

Request To Clarify Service Life of Affected Parts

    American Airlines requested clarification on why paragraph (i)(3) 
of the proposed AD allows chemical oxygen generators to remain in 
service longer than 10 years. American Airlines stated that paragraph 
(i)(3) of the proposed AD contradicts paragraph (h) of the proposed AD 
and leads to confusion.
    The FAA agrees to clarify. Currently, there are units with a 
manufacturing date older than 10 years that are potentially installed 
on airplanes, and these units might be included in the group identified 
in paragraph (i)(3) of this AD. After the initial replacement required 
by paragraph (i)(3) of this AD, the introductory text to paragraph (i) 
of this AD requires operators to replace affected units before 
exceeding 10 years since date of manufacture. To determine the 
appropriate compliance time for paragraph (i)(3) of this AD, the FAA 
assessed the failure rate of the units, the number of suspect units, 
and the probability of an unsafe outcome. The FAA has not changed this 
AD in this regard.

Request To Remove the 30-Day Compliance Time for Inspection of Part 
Numbers

    American Airlines and Delta Air Lines requested removing the 30-day 
compliance time for the inspection of the chemical oxygen generators 
part numbers. American Airlines stated that inspecting the part numbers 
alone does not provide any increase in safety and will severely disrupt 
the regular maintenance of the airplane with the potential to impact 
passengers if other work has to be postponed to meet a 30-day 
inspection requirement. Instead of requiring the 6-, 12-, and 24-month 
replacement, American Airlines suggested allowing 12 months to inspect 
and correct the units. Delta Air Lines recommended allowing operators 
to use existing methods to obtain chemical oxygen generator part 
numbers and dates of manufacture at a time that works within the needs 
of their operation rather than within 30 days. Delta Air Lines stated 
that the existing methods have already been reviewed by the operators' 
Certificate Management Office (CMO) and is FAA approved.
    The FAA disagrees with the request to remove the 30-day compliance 
time for the part number inspection. The FAA disagrees with Delta Air 
Lines' recommendation to allow operators' existing methods to inspect 
the chemical oxygen generators part numbers and date of manufacture 
that work within the needs of their operation rather than within this 
AD's compliance time. The FAA also disagrees with replacing this AD's 
proposed compliance times with the American Airlines' proposed 12-month 
compliance time to inspect and correct units. The commenter did not 
provide justification to substantiate how a 12-month compliance time to 
inspect and correct units provides an acceptable level of safety. 
Passenger chemical oxygen generators identified in paragraph (i)(1) of 
this AD must be replaced sooner than the proposed 12-month compliance 
time. After considering all of the available information, the FAA 
determined that the compliance time, as proposed, represents an 
appropriate interval of time in which the required actions can be 
performed in a timely manner within the affected fleet, while still 
maintaining an adequate level of safety. When developing the compliance 
time, the FAA considered the estimated hours to complete the inspection 
and replacements and the availability of parts. There are provisions in 
paragraph (g) of this AD that allow review of the airplane maintenance 
records in lieu of

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an inspection, provided the date of manufacture can be conclusively 
determined by that review. Under the provisions of paragraph (k) of 
this AD, operators may apply for an extension of the compliance times 
by providing rationale explaining why a compliance time extension 
provides an acceptable level of safety. The FAA has not changed this AD 
in this regard.

Request To Remove Inspection for Retired and Long-Term Storage 
Airplanes

    American Airlines requested that inspection of retired airplanes or 
airplanes in long-term storage not be required until the airplane goes 
into service.
    The FAA agrees that operators are not required to inspect retired 
airplanes because retired airplanes are not in service. And the FAA 
agrees that airplanes in long-term storage are not required to comply 
with the requirements of this AD until the airplane goes into service 
(14 CFR 39.7). If the compliance time has passed before a stored 
airplane is returned to service, it is not a violation. A violation 
occurs only if a product is operated that does not meet the 
requirements of an AD. Under the provisions of paragraph (k) of this 
AD, an operator who is unable to accomplish the inspection in this AD 
within the specified compliance time may request an alternative method 
of compliance (AMOC) to extend this time. The FAA has not changed this 
AD in this regard.

Request Six Months To Revise Manuals

    American Airlines requested six months to revise applicable 
manuals.
    The FAA disagrees with the request to require six months to revise 
applicable manuals. This AD requires only inspection of the chemical 
oxygen generator part numbers and replacement of chemical oxygen 
generators. This AD does not mandate revising applicable manuals. The 
FAA has not changed this AD in this regard.

Request Six Months To Purge Inventory

    American Airlines requested six months to purge inventory of P/N 
117080-XX chemical oxygen generators.
    The FAA disagrees with the request to require six months to purge 
inventory of P/N 117080-XX chemical oxygen generators. This AD requires 
only inspection of the chemical oxygen generator part numbers and 
replacement of chemical oxygen generators. This AD does not mandate 
purging inventory of P/N 117080-XX chemical oxygen generators. The FAA 
has not changed this AD in this regard.

Request To Confirm Life Limit of AVOX Systems Part Number P/N 807218-03

    American Airlines requested confirmation that FAA has determined 
AVOX Systems part number (P/N) 807218-03 does not have the same 
problems as P/N 117080-04 and continues to be an approved part number 
with a life of 15 years from the date of manufacture. AVOX Systems P/N 
807218-03 has been qualified to both Boeing Spec S417T401-44 (or Drager 
P/N E71740-00) and Boeing Spec S417T401-60 (or Collins P/N 117080-04).
    The FAA confirms that AVOX Systems P/N 807218-03 does not have the 
same problems as P/N 117080-04. The life limit for AVOX Systems P/N 
807218-03 is 15 years from the date of manufacture. Because this AD 
does not address P/N 807218-03, no change to this AD is necessary.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that the installation of winglets 
per Supplemental Type Certificate (STC) ST00830SE, STC ST01219SE, STC 
ST01518SE, and STC ST01920SE on applicable Boeing models subject to the 
proposed AD does not affect compliance with the mandated actions.
    The FAA agrees with the commenter that STC ST00830SE, STC 
ST01219SE, STC ST01518SE, and STC ST01920SE do not affect the ability 
to accomplish the actions required by this AD. The FAA has not changed 
this AD in this regard.

Request Use of Illustrated Parts Catalog To Determine Approved Part 
Numbers

    Delta Air Lines requested clarification on how to determine whether 
a part number is approved. Paragraph (h)(2) of this AD does not have 
any provision to allow operators to determine if a part number is 
approved. Delta Air Lines assumed operators may use the airplane 
Illustrated Parts Catalog (IPC) to determine acceptable approved 
alternate parts.
    The FAA confirms that operators may use the airplane IPC to 
determine acceptable approved part numbers. The FAA has not changed 
this AD in this regard.

Request To Define Acceptable Replacement Chemical Oxygen Generators

    Delta Air Lines requested that paragraph (i) of the proposed AD be 
revised to explicitly state that chemical oxygen generators be replaced 
with serviceable units during the repetitive replacement.
    The FAA agrees with the comment and has revised the introductory 
text to paragraph (i) of this AD accordingly.

Request To Limit Replacement Requirement Based on Date of Manufacture

    Delta Air Lines suggested that paragraph (i) of the proposed AD be 
revised to state that no replacement is necessary for affected 
passenger chemical oxygen generators that have a date of manufacture in 
2014 or later. Delta inferred that since these generators would have a 
manufacture date of 2014 or later, and therefore be within the new 10-
year life limit, replacement would not be mandated per the proposed AD.
    The FAA disagrees that units that have a date of manufacture in 
2014 or later need not be replaced. The FAA has added paragraph (i)(4) 
of this AD to clarify that units with a date of manufacture in 2014 or 
later must be replaced before exceeding 10 years since the date of 
manufacture, with a 24-month grace period that will allow for timely 
and orderly replacement of units that are close to their 10-year life 
limit.

Request To Clarify Affected Airplanes

    The United Parcel Service (UPS) Airlines requested limiting the 
proposed AD to apply only to the affected airplane models with part 
number 117080-02, 117080-03, or 117080-04 chemical oxygen generators 
installed. The commenter noted that the proposed AD would require 
accomplishment of paragraphs (g) and (i) on all of the airplane models 
covered by paragraph (c) of the proposed AD, even if an applicable 
airplane does not have part number 117080-02, 117080-03, or 117080-04 
installed.
    The FAA disagrees with the commenter's request. The FAA determined 
that the part number 117080-02, 117080-03, or 117080-04 chemical oxygen 
generators are rotable. This AD therefore applies to all airplanes of 
the affected models to ensure that no person installs a non-serviceable 
passenger chemical oxygen generator on an airplane that was initially 
delivered with an acceptable unit, thereby subjecting that airplane to 
the unsafe condition. The FAA has not changed this AD in this regard.

Additional Change to AD

    The compliance time in paragraph (i)(1) of this AD has been 
adjusted to accommodate airplanes with generators close to the 15-year 
life limit as of the effective date of the AD. This change is not more 
restrictive than what was proposed, and does not expand the

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scope of the requirement as specified in the proposed AD.

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.

Related Service Information

    Collins Aerospace Service Information Letter (SIL) 117080-SIL-002, 
dated May 4, 2022, specifies procedures for replacing affected chemical 
oxygen generators.

Costs of Compliance

    The FAA estimates that this AD affects 3,419 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
          Action                Labor cost            Parts cost         Cost per product         operators
----------------------------------------------------------------------------------------------------------------
Inspection...............  4 work-hours x $85    $0..................  $340................  $1,162,460.
                            per hour = $340.
Replacement..............  0.50 work-hour x $85  Up to $445..........  Up to $488 per        $1,668,472 per
                            per hour = $43 per                          replacement cycle.    replacement cycle.
                            replacement cycle.
----------------------------------------------------------------------------------------------------------------

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:

2023-13-12 The Boeing Company: Amendment 39-22497; Docket No. FAA-
2022-1479; Project Identifier AD-2022-00703-T.

(a) Effective Date

    This airworthiness directive (AD) is effective September 5, 
2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-100, 737-
200, 737-200C, 737-300, 737-400, 737-500, 737-600, 737-700, 737-
700C, 737-800, 737-900, 737-900ER, 757-200, 757-200PF, 757-200CB, 
757-300, 767-200, 767-300, 767-300F, and 767-400ER series airplanes, 
certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 35, Oxygen.

(e) Unsafe Condition

    This AD was prompted by reports of premature aging of certain 
chemical oxygen generators. The FAA is issuing this AD to address 
this premature aging that resulted in the generators failing to 
activate, which could fail to deliver oxygen during an emergency, 
possibly resulting in injury to the airplane occupants.

(f) Compliance

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

(g) Oxygen Generator Part Number Inspection

    Within 30 days after the effective date of this AD: Inspect 
passenger chemical oxygen generators having part numbers 117080-02, 
117080-03, and 117080-04 to determine their date of manufacture. A 
review of airplane maintenance records is acceptable for the 
inspection, provided the date of manufacture can be conclusively 
determined by that review.

(h) Definition

    For purposes of this AD, a serviceable unit is a passenger 
chemical oxygen generator that meets the condition specified in 
either paragraph (h)(1) or (2) of this AD.
    (1) Part numbers 117080-02, 117080-03, and 117080-04, with a 
manufacturing date not older than 10 years.
    (2) Approved part numbers other than 117080-02, 117080-03, and 
117080-04, provided the generator has not exceeded the life limit 
established for that generator by the manufacturer.

(i) Oxygen Generator Replacement

    For any passenger chemical oxygen generators having part numbers 
117080-02, 117080-03, and 117080-04: At the applicable time 
specified in paragraph (i)(1) through (4) of this AD, replace the 
chemical oxygen generator with a serviceable unit, as defined in 
this AD. Thereafter, replace chemical oxygen generators having part 
numbers 117080-02, 117080-03, and 117080-04 with serviceable units, 
as defined in this AD,

[[Page 49287]]

before exceeding 10 years since date of manufacture.
    Note 1 to paragraph (i): Additional guidance for replacing the 
affected passenger chemical oxygen generators can be found in 
Collins Aerospace Service Information Letter 117080-SIL-002, dated 
May 4, 2022, and approved maintenance procedures.
    (1) After doing the inspection in paragraph (g) of this AD: If 
the passenger chemical oxygen generator has a date of manufacture in 
2008 or earlier, replace before further flight or within 15 years 
since the date of manufacture, whichever occurs later.
    (2) For passenger chemical oxygen generators that have a date of 
manufacture in 2009 or 2010: Replace within 12 months after the 
effective date of this AD.
    (3) For passenger chemical oxygen generators that have a date of 
manufacture in 2011, 2012, or 2013: Replace within 24 months after 
the effective date of this AD.
    (4) For passenger chemical oxygen generators that have a date of 
manufacture in 2014 or later: Replace before exceeding 10 years 
since the date of manufacture, or within 24 months after the 
effective date of this AD, whichever occurs later.

(j) Parts Installation Limitation

    As of the effective date of this AD, no person may install a 
passenger chemical oxygen generator, unless the oxygen generator is 
a serviceable unit, as defined in this AD.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Continued Operational Safety 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 (l)(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, 
Continued Operational Safety 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.

(l) Related Information

    (1) For more information about this AD, contact Nicole S. Tsang, 
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 
98198; phone: 206-231-3959; email: [email protected].
    (2) For Collins Aerospace service information identified in this 
AD that is not incorporated by reference, contact Collins Aerospace, 
15701 West 95th Street, Lenexa, KS 66219; email 
[email protected]; website tpi.beaerospace.com/Authentication. 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.

(m) Material Incorporated by Reference

    None.

    Issued on June 30, 2023.
Michael Linegang,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-16121 Filed 7-28-23; 8:45 am]
BILLING CODE 4910-13-P

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