DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-1109; Product Identifier 2020-NM-067-AD; Amendment
39-21383; AD 2021-01-07]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD)
for
certain The Boeing Company Model 737-700 series airplanes. This AD
requires repetitive testing to verify correct operation of the smoke
clearance mode of the equipment cooling system and low pressure
environmental control system, and corrective actions if necessary. This
AD also requires installing new relays and changing the wiring to the
environmental control system, among other actions. This AD was prompted
by a determination that a repetitive test is needed to assess the
components on airplanes equipped with a certain air distribution system
configuration. The FAA is issuing this AD to address the unsafe
condition on these products.
DATES: This AD is effective March 9, 2021.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of March 9,
2021.
The FAA must receive comments on this AD by April 8, 2021.
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 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, 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-
1109.
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-
1109; 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
street address for Docket Operations is listed above. Comments will be
available in the AD docket shortly after receipt.
FOR FURTHER INFORMATION CONTACT: Susan L. Monroe, Aerospace Engineer,
Cabin Safety and Environmental Systems Section, FAA, Seattle ACO
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-
231-3570; email: susan.l.monroe@faa.gov.
SUPPLEMENTARY INFORMATION:
Discussion
The FAA has determined that a repetitive test is needed to assess
the components on airplanes equipped with a certain air distribution
system configuration. A review by Boeing found that there was no
maintenance procedure available to assess the components used to
reconfigure the air distribution system to the cargo fire mode. Without
the repetitive test, failures of components could be latent for
extended periods. This condition, if not addressed, could result in
latent failures of the equipment cooling system and low pressure
environmental control system, which, in combination with a cargo fire
event, could result in smoke in the flight deck and/or main cabin, and
possible loss of aircraft control.
Other Related Rulemaking
The FAA issued AD 2016-04-06, Amendment 39-18400 (81 FR 9756,
February 26, 2016) (AD 2016-04-06), applicable to all The Boeing
Company Model 737-600, -700, -700C, -800, -900, and -900ER series
airplanes. That AD requires doing repetitive testing to verify correct
operation of the equipment cooling system and low pressure
environmental control system, and corrective actions if necessary. That
AD also requires, for certain airplanes, installing new relays and
changing the wiring to the environmental control system. That AD was
prompted by a determination that a repetitive test is needed to inspect
the components on airplanes equipped with a certain air distribution
system configuration. The actions required by that AD are intended to
address latent failures of the equipment cooling system and low
pressure environmental control system, which, in combination with a
cargo fire event, could result in smoke in the flight deck and/or main
cabin, and possible loss of aircraft control.
Since issuance of that AD, the FAA has determined that additional
actions are necessary to address the same unsafe condition identified
in AD 2016-04-06 for The Boeing Company Model 737-700 series airplanes
having line numbers (L/Ns) 481, 545, 684, 979, 1089, 1211, and 1223.
Those actions have been included in the revised service information
specified in paragraphs (g) and (h) of this AD. This AD adds the
requirements of paragraph (h) that include installing new relays and
changing the wiring to the environmental control system, and
accomplishing certain concurrent actions, for the affected airplanes.
Relationship Between This AD and AD 2016-04-06
This AD does not supersede AD 2016-04-06. Rather, the FAA has
determined that a stand-alone AD would be more appropriate to address
the requirements of this AD. AD 2016-04-06 did not address the unsafe
condition for the 7 airplanes mentioned previously and identified in
paragraph (c) of this AD. To address the unsafe condition for these 7
airplanes, this AD requires repetitive testing to verify correct
operation of the smoke clearance mode of the equipment cooling system
and low pressure environmental control system, and corrective actions
if necessary; and also requires installing new relays and changing the
wiring to the environmental control system, and accomplishing certain
concurrent actions. As such, this AD terminates all of the requirements
of AD 2016-04-06 for the airplanes identified in paragraph (c) of this
AD only.
Related Service Information Under 1 CFR Part 51
The FAA reviewed the following service information:
Boeing Alert Service Bulletin 737-26A1122, Revision 3, dated
January 31, 2020. This service information describes procedures for
installing new relays and changing the wiring to the environmental
control system.
Boeing Alert Service Bulletin 737-26A1137, Revision 2, dated
January 27, 2020. This service information describes procedures for
repetitive testing to verify correct operation of the smoke clearance
mode of the equipment cooling system and low pressure environmental
control system, and applicable corrective actions.
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 issuing 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.
AD Requirements
This AD requires accomplishing the actions specified in the service
information described previously.
FAA's Justification and Determination of the Effective Date
There are currently no domestic operators of these products.
Therefore, the FAA finds that notice and opportunity for prior public
comment are unnecessary and that good cause exists for making this
amendment effective in less than 30 days.
Comments Invited
This AD is a final rule that involves requirements affecting flight
safety and was not preceded by notice and an opportunity for public
comment. However, the FAA invites you to send any written data, views,
or arguments about this final rule. Send your comments to an address
listed under the ADDRESSES section. Include Docket No. FAA-2020-1109
and Product Identifier 2020-NM-067-AD at the beginning of your
comments. The FAA specifically invites comments on the overall
regulatory, economic, environmental, and energy aspects of this final
rule. The FAA will consider all comments received by the closing date
and may amend this final rule 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, as well
as a report summarizing each substantive public contact with FAA
personnel concerning this AD. The FAA will consider all comments
received by the closing date for comments. The FAA may amend this AD
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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Susan
L. Monroe, Aerospace Engineer, Cabin Safety and Environmental Systems
Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA
98198; phone and fax: 206-231-3570; email: susan.l.monroe@faa.gov. Any
commentary that the FAA receives that is not specifically designated as
CBI will be placed in the public docket for this rulemaking.
Regulatory Flexibility Act (RFA)
The requirements of the RFA do not apply when an agency finds good
cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and
comment. Because the FAA has determined that it has good cause to adopt
this rule without notice and comment, RFA analysis is not required.
Costs of Compliance
Currently, there are no affected U.S.-registered airplanes. For any
affected airplane that is imported and placed on the U.S. Register in
the future, the FAA provides the following cost estimates to comply
with this AD:
Estimated Costs
Action |
Labor cost |
Parts cost |
Cost per product |
Operational Test |
4 work-hours x $85 per hour =
$340 per test cycle |
$0 |
$340 per test cycle |
New relays/wiring changes |
104 work hours x $85 per hour
= $8,840 |
11,417 |
$20,257 |
We estimate the following costs to
do any necessary system fault
isolation and replacements that would be required based on the results
of the operational test. We have no way of determining the number of
aircraft that might need these actions:
On-Condition Costs
Action |
Labor cost |
Parts cost |
Cost per product |
Perform system fault isolation
and replace faulty component. |
10 work-hours x $85 per hour
= $850 |
$0 |
$850 |
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, and
(2) Will not affect intrastate aviation in Alaska.
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
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]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:
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