DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-9189; Product Identifier 2016-NM-114-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening
of comment period.

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SUMMARY: We are revising an earlier proposal for certain The Boeing
Company Model 737-600, -700, -700C, -800, -900, and -900ER series
airplanes. This action revises the notice of proposed rulemaking (NPRM)
by adding airplanes to the applicability and adding a measurement of
the distance between the hooks of the torsion spring of the lanyard
assembly. We are proposing this airworthiness directive (AD) to address
the unsafe condition on these products. Since these actions would
impose an additional burden over those in the NPRM, we are reopening
the comment period to allow the public the chance to comment on these
changes.

DATES: The comment period for the NPRM published in the Federal
Register on October 13, 2016 (81 FR 70647), is reopened.

We must receive comments on this SNPRM by October 29, 2018.

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 http://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: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.

For service information identified in this SNPRM, 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. It is also
available on the internet at http://www.regulations.gov by searching
for and locating Docket No. FAA-2016-9189.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.gov
by searching for and locating Docket No. FAA-2016-
9189; 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 SNPRM, the regulatory evaluation, any comments received, and other
information. The street address for Docket Operations (phone: 800-647-
5527) is in the ADDRESSES section. Comments will be available in the AD
docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Scott Craig, Aerospace Engineer, Cabin
Safety and Environmental Systems Section, FAA, Seattle ACO Branch, 2200
South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3566;
email: michael.s.craig@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2016-9189;
Product Identifier 2016-NM-114-AD" at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this SNPRM. We will consider all
comments received by the closing date and may amend this SNPRM because
of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,
including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this SNPRM.

Discussion

We issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to certain The Boeing Company Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes. The NPRM published in the
Federal Register on October 13, 2016 (81 FR 70647). The NPRM was
prompted by reports of passenger service units (PSUs) becoming detached
from the supporting airplane structure in several Model 737 airplanes
during survivable accidents. The NPRM proposed to require modifying the
PSUs and life vest panels by replacing the existing inboard lanyard and
installing two new lanyards on the outboard edge of the PSUs and life
vest panels.

Actions Since the NPRM Was Issued

Since we issued the NPRM, we have determined that additional
airplanes are subject to the unsafe condition. In addition, we have
determined that the torsion spring of a certain lanyard assembly may be
manufactured incorrectly and have an inadequate distance between the
hooks of the torsion spring. Since the discrepant torsion springs may
have been installed in production, as well as on airplanes modified in
accordance with Boeing Service Bulletin 737-25-1707, dated September
24, 2015, we have determined that it is necessary to measure the
distance between the hooks of the torsion spring of the lanyard
assembly and replace discrepant lanyard assemblies.

Comments

We gave the public the opportunity to comment on the NPRM. The
following presents the comments received on the NPRM and the FAA's
response to each comment.

Support for the NPRM

The National Transportation Safety Board (NTSB) and commenter
London Smith expressed their support for the NPRM.

Effect of Winglets on Accomplishment of the Proposed Actions

Aviation Partners Boeing stated that the installation of winglets
per Supplemental Type Certificate (STC) ST00830SE does not affect the
accomplishment of the manufacturer's service instructions.

We agree with the commenter that STC ST00830SE does not affect the
accomplishment of the manufacturer's service instructions. Therefore,
the installation of STC ST00830SE does not affect the ability to
accomplish the actions that would be required by this SNPRM. We have
not changed this SNPRM in this regard.

Request To Extend the Compliance Time

Japan Airlines (JAL) and American Airlines (AA) requested that the
compliance time in paragraph (g) of the proposed AD be extended from 60
months to 84 months. JAL suggested that, due to Boeing's manufacturing
schedule for the kits, Boeing might not manufacture an adequate number
of kits within the proposed compliance time. AA stated that extending
the compliance time would allow operators to perform the modification
during regularly scheduled heavy maintenance checks, thereby reducing
the financial burden on operators.

We disagree with the requests. In developing an appropriate
compliance time for this action, we considered the urgency of the
unsafe condition along with the practical aspect of accomplishing the
required modification at a time corresponding to the normal scheduled
maintenance for most operators. According to the manufacturer, an
adequate number of modification kits will be available to modify the
affected fleet within the proposed compliance time. However, under the
provisions of paragraph (i) of this SNPRM, we will consider requests
for approval of an extension of the compliance time if sufficient data
are submitted to substantiate that the new compliance time would
provide an acceptable level of safety. We have not changed this SNPRM
in this regard.

Request To Clarify Service Information Requirements

AA requested that we clarify that data notes (b) and (d) to Figure
1 of Boeing Service Bulletin 737-25-1707, dated September 24, 2015, can
be complied with in accordance with an operator's procedures. AA noted
paragraph 3.B.1.b. of the Accomplishment Instructions of Boeing Service
Bulletin 737-25-1707, dated September 24, 2015, which requires the
installation of new lanyards in accordance with Figure 1 of the service
information, is a Required for Compliance (RC) step. AA added that data
notes (b) and (d) to Figure 1 of Boeing Service Bulletin 737-25-1707,
dated September 24, 2015, provide latitude when the operator has an
accepted alternative procedure by using the term "refer to."

We agree to clarify that the operator is allowed latitude in
accomplishing work steps that use the term "refer to." If a step is
marked RC and a procedure or document may be followed to accomplish an
action (e.g., the design approval holder's procedure or document may be
used, but an FAA-accepted procedure could also be used), the
appropriate terminology to use to cite the procedure or document is
"refer to . . . as an accepted procedure." We have not changed this
SNPRM in this regard.

Request To Add Airplanes to the Applicability

United Airlines (UAL) noted that the proposed AD did not refer to
the PSUs on Model 757-200 and -300 airplanes, which can have the same
part numbers as the airplanes addressed by the proposed AD. UAL stated
that operators who operate both of these fleet types need to review the
risk of having both pre- and post-AD parts in their inventory. UAL
added that they will mitigate the risk of potential parts intermingling
by modifying their Model 757-200 and -300 airplanes with the same PSU
modification.

We infer that UAL requests that Model 757-200 and -300 series
airplanes should be included in the applicability of this proposed AD.
We agree to investigate whether a similar unsafe condition exists on
Model 757-200 and -300 series airplanes. We will take appropriate
action based on the result of that investigation. However, delaying
this SNPRM in order to determine if Model 757 airplanes should be added
to the applicability would be inappropriate given that we
have determined that an unsafe condition exists and that the
modifications must be done to ensure continued safety. We have not
changed this SNPRM in this regard.

Request To Change Text To Match the Service Information

Boeing requested that we change wording in the proposed AD that
discusses ". . . removing the existing lanyard and installing two new
lanyards. . ." to instead read ". . . replacing the existing lanyard
and installing two new lanyards. . . ." Boeing stated that the
proposed text more accurately describes the modification required by
the service bulletin.

We agree with the request. We have updated the wording of the
applicable sentence in the Discussion and Related Service Information
under 1 CFR part 51 sections of this SNPRM.

Request To Clarify Language Describing What Prompted the AD

Boeing requested that the word "incidents" be changed to
"accidents" in language describing what prompted the proposed AD.
Boeing noted that the events in which PSUs became detached were
accidents, not incidents, as defined by the NTSB and International
Civil Aviation Organization (ICAO) Annex 13.

We agree to make this change, which will more accurately define
these events according to industry standards. We have updated the
Discussion section and paragraph (e) of this SNPRM to reflect this
change.

Request To Refer to New Service Information

Boeing requested that we update the proposed AD to refer to Boeing
Service Bulletin 737-25-1707, Revision 1, dated May 18, 2018, which was
recently released. Boeing stated that the service bulletin would be
revised to include the 737NG Boeing Business Jet (BBJ) aircraft
effectivity blocks, which were omitted in the original revision of the
service bulletin.

We agree with the commenter's request. Boeing Service Bulletin 737-
25-1707, Revision 1, dated May 18, 2018, adds airplanes to the
effectivity, adds a new measurement of the torsion spring of the
lanyard assembly, and clarifies the instructions for attaching the
lanyard assembly torsion spring to the PSU rail. For these reasons, we
have updated this SNPRM to refer to Boeing Service Bulletin 737-25-
1707, Revision 1, dated May 18, 2018.

Related Service Information Under 1 CFR Part 51

We reviewed Boeing Service Bulletin 737-25-1707, Revision 1, dated
May 18, 2018. This service information describes procedures for
modifying the PSUs and life vest panels by replacing the existing
inboard lanyard and installing two new lanyards on the outboard edge of
the PSUs and life vest panels, measuring the distance between the hooks
of the torsion spring of the lanyard assembly, replacing any discrepant
lanyard assemblies, and re-identifying serviceable lanyard assemblies.
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

We are proposing this AD because we 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.
Certain changes described above expand the scope of the NPRM. As a
result, we have determined that it is necessary to reopen the comment
period to provide additional opportunity for the public to comment on
this SNPRM.

Proposed Requirements of This SNPRM

This SNPRM would require accomplishment of the actions identified
as "RC" (required for compliance) in the Accomplishment Instructions
of Boeing Service Bulletin 737-25-1707, Revision 1, dated May 18, 2018,
described previously, except as discussed under "Differences Between
this SNPRM and the Service Information," and except for any
differences identified as exceptions in the regulatory text of this
proposed AD. For information on the procedures and compliance times,
see this service information at http://www.regulations.gov by searching
for and locating Docket No. FAA-2016-9189.

Differences Between This SNPRM and the Service Information

The effectivity of Boeing Service Bulletin 737-25-1707, Revision 1,
dated May 18, 2018, is limited to Model 737-600, -700, -700C, -800,
-900, and -900ER series airplanes, line numbers 1 through 6009, without
a Boeing Sky Interior (BSI). However, the applicability of this
proposed AD includes all Boeing Model 737-600, -700, -700C, -800, -900,
and -900ER series airplanes without a BSI. Because the affected lanyard
assemblies are rotable parts, we have determined that these parts could
later be installed on airplanes that were initially delivered with
acceptable lanyard assemblies, thereby subjecting those airplanes to
the unsafe condition. This difference has been coordinated with Boeing.

Costs of Compliance

We estimate that this proposed AD affects 2,015 airplanes of U.S.
registry. We estimate the following costs to comply with this proposed AD:

Estimated Costs

According to the manufacturer, some or all of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected individuals. We do not control warranty coverage for
affected individuals. As a result, we have included all known costs in
our cost estimate.

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.

We are 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.

This proposed AD is issued in accordance with authority delegated
by the Executive Director, Aircraft Certification Service, as
authorized by FAA Order 8000.51C. In accordance with that order,
issuance of ADs is normally a function of the Compliance and
Airworthiness Division, but during this transition period, the
Executive Director has delegated the authority to issue ADs applicable
to transport category airplanes to the Director of the System Oversight
Division.

Regulatory Findings

We 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) Is not a "significant rule" under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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

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 (AD):