Document ID: FAA-2016-3697-0010
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2017-05-05T04:00Z

[Federal Register Volume 82, Number 86 (Friday, May 5, 2017)]
[Proposed Rules]
[Pages 21146-21153]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-07938]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-3697; Directorate Identifier 2015-NM-143-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 proposed airworthiness directive 
(AD) that proposed to supersede AD 2011-01-15, which applies to certain 
The Boeing Company Model 757-200, -200CB, and -300 series airplanes. AD 
2011-01-15 requires repetitive inspections for cracking of the fuselage 
skin of the crown skin panel along the chem-milled step at certain 
stringers, and repair, if necessary. This action revises the notice of 
proposed rulemaking (NPRM) by reducing the compliance time for certain 
inspections. We are proposing this AD to address the unsafe condition 
on these products. Since these actions impose an additional burden over 
that proposed in the NPRM, we are reopening the comment period to allow 
the public the chance to comment on these proposed changes.

DATES: We must receive comments on this SNPRM by June 19, 2017.

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.

[[Page 21147]]

     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; telephone 
562-797-1717; Internet https://www.myboeingfleet.com. You may view this 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the 
availability of this material at the FAA, call 425-227-1221. It is also 
available on the Internet at http://www.regulations.gov by searching 
for and locating Docket No. FAA-2016-3697.

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-
3697; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this proposed AD, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Eric Schrieber, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 
562-627-5348; fax: 562-627-5210; email: eric.schrieber@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2016-3697; 
Directorate Identifier 2015-NM-143-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD 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 proposed AD.

Discussion

    We issued an NPRM to amend 14 CFR part 39 to supersede AD 2011-01-
15, Amendment 39-16572 (76 FR 1351, January 10, 2011) (``AD 2011-01-
15''). AD 2011-01-15 applies to certain The Boeing Company Model 757-
200, -200CB, and -300 series airplanes. AD 2011-01-15 requires 
repetitive inspections for cracking of the fuselage skin of the crown 
skin panel along the chem-milled step at stringers S-4L and S-4R, from 
station (STA) 297 through STA 439, and repair if necessary. AD 2011-01-
15 also includes terminating action for the repetitive inspections of 
the repaired areas only. AD 2011-01-15 resulted from reports of 
cracking in the fuselage skin of the crown skin panel. The NPRM 
published in the Federal Register on February 18, 2016 (81 FR 8157) 
(``The NPRM''). The NPRM was prompted by reports of the initiation of 
new fatigue cracking in the fuselage skin of the crown skin panel along 
locally thinned channels adjacent to the chem-milled steps. The NPRM 
proposed to add repetitive inspections for cracking in additional areas 
and repair if necessary. The NPRM also proposed to remove airplanes 
from the applicability in AD 2011-01-15. The NPRM also proposed to add 
an optional skin panel replacement which would terminate all 
inspections and an optional preventative modification that would 
terminate certain inspections.

Actions Since the NPRM Was Issued

    Since we issued the NPRM, we have received a report that cracking 
was found earlier than the compliance time specified for the Zone 1 
inspections identified in Boeing Special Attention Service Bulletin 
757-53-0097, Revision 2, dated July 28, 2015 (referenced in the NPRM as 
the appropriate source of service information for accomplishing the 
specified actions). Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016, has been issued to reduce the 
compliance time for the Zone 1 inspections.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 3, dated December 2, 2016. The service information describes 
procedures for repetitive external sliding probe eddy current (EC) and 
external spot-probe-medium-frequency EC inspections for cracking of the 
crown skin panel, repair, a preventive modification, and replacement of 
the crown skin panel. 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.

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

    FedEx provided comments that support the intent of the NPRM. FedEx 
also stated that the inspection area is within the affected area of its 
passenger-to-freighter modification per supplemental type certificate 
(STC) ST03562AT. FedEx noted that ST Aerospace will apply for an 
alternative method of compliance (AMOC).

Request To Reduce the Compliance Threshold for Zone 1 Inspections

    Boeing asked that we change paragraph (g)(1) of the proposed AD to 
reduce the compliance threshold for the Zone 1 inspections from 18,000 
to 15,000 total flight cycles. Boeing stated that a grace period could 
be provided for airplanes that have exceeded 15,000 total flight 
cycles. Boeing noted that an operator reported a crack finding in Zone 
1 that occurred on an airplane with 15,722 total flight cycles. Boeing 
added that previous data supported the threshold of 18,000 flight 
cycles, but this new finding supports the 15,000 total flight cycle 
threshold. Boeing stated that since FAA letter 120S14-181, dated March 
26, 2014 (which extends the compliance times specified in AD 2011-01-
15), and Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 2, dated July 28, 2015 (which specifies the 18,000 flight-
cycle compliance time), were released, some operators may have 
suspended or delayed inspections beyond 15,000 total flight cycles and 
up to 18,000 total flight cycles. Boeing added that a short grace 
period of 200 flight cycles or 90 days (which is similar to the grace 
period in AD 2011-01-15) should be applied for

[[Page 21148]]

the initial inspection for airplanes on which the 15,000 total flight 
cycle threshold has been exceeded.
    We agree with the commenter's request to reduce the compliance 
threshold for the Zone 1 inspections from 18,000 to 15,000 total flight 
cycles, for the reasons provided. Boeing Special Attention Service 
Bulletin 757-53-0097, Revision 3, dated December 2, 2016, has been 
issued to reduce the compliance time for the Zone 1 inspections. We 
have changed the compliance time specified in paragraph (g)(1) of this 
proposed AD and added a new paragraph (h) to this proposed AD to 
specify the reduced compliance times.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing the STC 
ST01518SE does not affect compliance with the actions specified in the 
NPRM.
    We agree with the commenter. We have redesignated paragraph (c) of 
the proposed AD (in the NPRM) as (c)(1) and added a new paragraph 
(c)(2) to this proposed AD to state that installation of STC ST01518SE 
does not affect the ability to accomplish the proposed actions. 
Therefore, for airplanes on which STC ST01518SE is installed, a 
``change in product'' AMOC approval request is not necessary to comply 
with the requirements of 14 CFR 39.17.

Request To Remove Certain Duplicate Language

    European Air Transport Leipzig GmbH and DHL Air Ltd. asked that we 
remove all duplicated data from the NPRM, and only refer to the 
compliance tables specified in Boeing Special Attention Service 
Bulletin 757-53-0097, Revision 2, dated July 28, 2015. The commenters 
stated that the compliance information is contained in detail in the 
referenced service information, and is repeated in the NPRM without 
benefit of clarification. The commenters added that the stringers 
identified for inspection in paragraphs (g)(3)(i) and (g)(3)(ii) of the 
proposed AD are incorrect, and should refer to inspection Zone 3 
containing stringers S-3L, S-2L, S-1, S-2R, and S-3R.
    We partially agree with the commenters' request. We agree to revise 
this proposed AD for clarity but we do not agree to remove all of the 
details for the required actions in this proposed AD. The stringers 
identified for inspection in paragraphs (g)(3)(i) and (g)(3)(ii) of the 
proposed AD are correct, as specified in the referenced service 
information. However, paragraphs (g)(3)(i) and (g)(3)(ii) of the 
proposed AD (in the NPRM) should have specified between stringers S-3L 
to S-3R instead of ``at stringers S-3L and S-3R.'' Since the stringer 
location is clear in the service information, we have removed the 
reference to the stringers in paragraphs (g)(3)(i) and (g)(3)(ii) of 
this proposed AD. Instead, we have added a reference to the Zone 3 
areas of Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 3, dated December 2, 2016.

Request To Clarify Zone 1 Inspection Language

    Boeing and United Airlines (UA) asked that we clarify the 
inspection language specified in paragraphs (g)(1)(i) and (g)(1)(ii) of 
the proposed AD. Boeing asked that we include ``Zone 1 areas'' and ``as 
applicable'' in the description. UA stated that it appears that the 
inspections are for ``Zone 1 areas.'' Boeing stated that the Zone 1 
areas are clearly delineated in Boeing Special Attention Service 
Bulletin 757-53-0097, Revision 2, dated July 28, 2015.
    We agree with the commenters' request for the reason provided. As 
stated previously, this proposed AD cites Boeing Special Attention 
Service Bulletin 757-53-0097, Revision 3, dated December 2, 2016. We 
have clarified the inspection language in paragraph (g)(1) of this 
proposed AD. We have also clarified similar inspection language in 
paragraph (g)(2) of this proposed AD.

Request To Clarify Optional Terminating Action

    UA asked that we clarify the optional terminating action in 
paragraph (j)(2) of the proposed AD, to eliminate the need for a new 
AMOC as terminating action for the inspections after replacing the 
crown skin panel using a method approved in accordance with paragraph 
(m) of the proposed AD. UA noted that Note (c) of Table 1, Note (b) of 
Table 2, and Note (b) of Table 3 of paragraph 1.E., ``Compliance,'' of 
Boeing Special Attention Service Bulletin 757-53-0097, Revision 2, 
dated July 28, 2015, stipulate that the skin replacement itself is 
considered terminating action to all inspections done in accordance 
with the referenced service information. UA added that this is based on 
the fact that the skin chem-mill process defect should not be present 
in the new skin. UA noted that this method of skin replacement is not 
part of the safety consideration, and should not require a new AMOC.
    We agree with the commenter's request. We have clarified paragraph 
(k)(2) of this proposed AD (which was referred to as paragraph (j)(2) 
of the proposed AD (in the NPRM)) to add replacing the crown skin panel 
in accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 757-53-0097, Revision 3, dated December 2, 
2016, or using a method approved in accordance with the procedures 
specified in paragraph (n) of this proposed AD (which was referred to 
as paragraph (m) of the proposed AD (in the NPRM)), terminates the 
inspections.

Request To Address the Possibility That Cracking May Have Been Found 
During Inspections Required by AD 2011-01-15

    Boeing asked that we include the possibility that cracking may have 
been found during the inspections required by paragraph (g) of AD 2011-
01-15 in the provisional requirements of paragraphs (g)(2) and (g)(3) 
of the proposed AD (in the NPRM). Boeing recommended including a 
reference to paragraph (g) of AD 2011-01-15 as follows: ``For airplanes 
on which any crack is found during any inspections required by 
Paragraph (g)(1) of this AD or previously per AD 2011-01-15, Paragraph 
(g); or any repair . . . .'' Boeing added that to exclude this language 
could lead operators to infer that it precludes previous findings from 
inclusion in the provisional statement.
    We acknowledge the commenter's concerns. As of the effective date 
of the final rule following this SNPRM, AD 2011-01-15 will no longer 
exist since it will be superseded by the new AD. For this reason, we do 
not typically refer to a superseded AD in a new AD requirement. 
However, paragraphs (g)(2) and (g)(3) of this proposed AD do include 
findings from paragraph (g) of AD 2011-01-15. Paragraph (h) of AD 2011-
01-15 states that a repair must be done before further flight if any 
crack is found. Therefore, for any crack found before the effective 
date of the final rule, the crack should already have been repaired. 
Paragraph (g)(2) of this proposed AD states ``. . . or any repair is 
installed that covers any portion of the Zone 1 inspection area . . .'' 
and that statement covers the crack findings in AD 2011-01-15.
    In addition, paragraph (m) of this proposed AD provides credit for 
Zone 1 inspections required by paragraph (g)(1) of this proposed AD, if 
those actions were performed before the effective date of the final 
rule using Boeing Special Attention Service Bulletin 757-53-0097, dated 
November 22, 2010; Revision 1, dated January 6, 2011; or Revision 2, 
dated July 28, 2015. We

[[Page 21149]]

have not changed this proposed AD in this regard.

Request To Include Credit for Previous Inspections

    Boeing and UA asked that a new paragraph (l)(3) be added to the 
proposed AD to provide credit for previous inspections done using 
previous revisions of the referenced service information to accomplish 
the inspections in paragraph (g)(1) of this AD. Those inspections were 
approved as an AMOC to AD 2011-01-15.
    We do not agree with the commenter's request. It is not necessary 
to include credit for inspections that were done using previous 
revisions of the referenced service information, because credit for 
those inspections is already provided in paragraph (m) of this proposed 
AD. Therefore, we have not changed this proposed AD in this regard.

Request To Include Credit for Previously Approved Repairs

    UA asked that we include credit language in this proposed AD for 
inspecting previously approved repairs, as specified in Note (a) of 
Table 1, Note (c) of Table 2, and Note (c) of Table 3 of paragraph 
1.E., ``Compliance,'' of Boeing Special Attention Service Bulletin 757-
53-0097, Revision 2, dated July 28, 2015. UA stated that including this 
credit would avoid unnecessary work stoppage and minimize future AMOC 
requests for repairs which meet these criteria.
    We agree that operators are allowed credit for inspecting 
previously approved repairs, as specified in the notes in Tables 1, 2, 
and 3 of paragraph 1.E., ``Compliance,'' of Boeing Special Attention 
Service Bulletin 757-53-0097, Revision 2, dated July 28, 2015. However, 
we do not agree that the language in those notes should be added to 
this proposed AD because Parts 1, 2, and 3 of the Work Instructions of 
Boeing Special Attention Service Bulletin 757-53-0097, Revision 3, 
dated December 2, 2016, also include those credit notes. This proposed 
AD requires accomplishing the specified actions in accordance with the 
Accomplishment Instructions, which includes those notes in the Work 
Instructions; therefore, operators are given credit. We have not 
changed this proposed AD in this regard.

Request To Clarify Certain Inspection Areas

    Boeing and UA asked that we clarify the inspection area in 
paragraphs (g)(2)(i) and (g)(2)(ii) of the proposed AD to include the 
Zone 2 areas, and also that we clarify the inspection area in 
paragraphs (g)(3)(i) and (g)(3)(ii) of the proposed AD to include the 
Zone 3 areas. Boeing and UA stated that the zones are identified in 
Boeing Special Attention Service Bulletin 757-53-0097, Revision 2, 
dated July 28, 2015.
    We agree with the commenters' requests for the reason provided. As 
stated previously, this proposed AD cites Boeing Special Attention 
Service Bulletin 757-53-0097, Revision 3, dated December 2, 2016. We 
have clarified the inspection language in paragraphs (g)(2)(i) and 
(g)(2)(ii), and (g)(3)(i) and (g)(3)(ii), of this proposed AD to 
include the Zone 2 and Zone 3 areas, respectively.

Request To Clarify Sections in Service Information With Inspection 
Instructions

    Boeing asked that we change paragraph (g)(1) of the proposed AD to 
clarify that the inspections should be done using the instructions 
specified in Part 1 or Part 2 of Boeing Special Attention Service 
Bulletin 757-53-0097, Revision 2, dated July 28, 2015. Boeing stated 
that this clarification would avoid confusion.
    We agree with the commenter's request for the reason provided. We 
have clarified paragraphs (g)(1), (g)(1)(i), and (g)(1)(ii) of this 
proposed AD to include doing the inspection as specified in Part 1 or 
Part 2 of Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 3, dated December 2, 2016.
    Boeing and UA asked that we change paragraph (g)(2) of the proposed 
AD to clarify that the Zone 2 inspections should be done using the 
instructions specified in Part 4 or Part 5 of Boeing Special Attention 
Service Bulletin 757-53-0097, Revision 2, dated July 28, 2015. Boeing 
stated that those areas are clearly identified in Boeing Special 
Attention Service Bulletin 757-53-0097, Revision 2, dated July 28, 
2015, and should be included for clarity.
    We agree with the commenter's request for the reason provided. We 
have clarified paragraphs (g)(2), (g)(2)(i), and (g)(2)(ii) of this 
proposed AD to include doing the Zone 2 inspections as specified in 
Part 4 or Part 5 of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016.
    Boeing and UA asked that we change paragraph (g)(3) of the proposed 
AD to clarify that the Zone 3 inspections should be done using the 
instructions specified in Part 6 or Part 7 of Boeing Special Attention 
Service Bulletin 757-53-0097, Revision 2, dated July 28, 2015. Boeing 
and UA stated that those areas are clearly identified in Boeing Special 
Attention Service Bulletin 757-53-0097, Revision 2, dated July 28, 
2015, and should be included for clarity.
    We agree with the commenters' request for the reason provided. We 
have clarified paragraphs (g)(3), (g)(3)(i), and (g)(3)(ii) of this 
proposed AD to include doing the Zone 3 inspections as specified in 
Part 6 or Part 7 of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016. The reference to Part 6 and 
Part 7 also applies to the repetitive inspections.

Request To Clarify Inspection Language

    Boeing asked that we clarify the inspection language in paragraph 
(j)(1) of the proposed AD to better describe the inspections required 
when doing the preventative modification. Boeing stated that it should 
specify doing high frequency eddy current open-hole inspections for 
cracking in existing fastener holes. Boeing noted that Boeing Special 
Attention Service Bulletin 757-53-0097, Revision 2, dated July 28, 
2015, clearly specifies using an open-hole inspection, and added that 
if this inspection is not defined it would permit operators to do a 
surface inspection around the fasteners, which is not sufficient to 
ensure there is no cracking in the fastener holes.
    Boeing also asked that we change the paragraph identifier at the 
end of paragraph (j)(1) of the proposed AD from (g) to (g)(1) since the 
referenced inspection is actually required by paragraph (g)(1) of the 
proposed AD. Boeing also asked that we change that paragraph identifier 
in paragraphs (l)(1) and (l)(2) of the proposed AD. Boeing stated that 
paragraph (g) of the proposed AD merely refers to the inspection 
paragraphs.
    We agree with the commenter's requests for the reasons provided. We 
have clarified the inspection language in paragraph (k)(1) of this 
proposed AD (which was referred to as paragraph (j)(1) of the proposed 
AD (in the NPRM)) to include ``. . . open-hole inspections for cracking 
in existing fastener holes.''
    We have also changed the paragraph identifiers in paragraphs (k)(1) 
and (m) of this proposed AD (which were referred to as paragraphs 
(j)(1), (l)(1), and (l)(2) of the proposed AD (in the NPRM)) to specify 
paragraph (g)(1) of this proposed AD accordingly.

Request To Clarify the Repair Area

    Boeing asked that we change paragraphs (g)(2) and (g)(3) of the 
proposed AD to clarify that the repair can cover ``any portion'' of the 
Zone 1

[[Page 21150]]

area, and asked that the description be changed to include those words. 
Boeing stated that currently the inspection area specified in those 
paragraphs could be interpreted as a repair that would need to cover 
the entire Zone 1 inspection area; however, operators typically install 
local repairs in areas where cracks are found.
    We agree with the commenter's request for the reason provided. We 
have clarified paragraphs (g)(2) and (g)(3) of this proposed AD to 
include the words ``any portion'' of the Zone 1 repair area to be 
inspected.

Request To Clarify the Description of the Preventative Modification

    Boeing asked that we change paragraphs (g)(2) and (g)(3) of the 
proposed AD to clarify that ``any preventative modification'' is 
actually ``the optional Zone 1 preventative modification specified in 
paragraph (j)(1) of the NPRM.'' Boeing stated that there is only one 
specific preventative modification specified in the referenced service 
information that necessitates the inspections in paragraphs (g)(2) and 
(g)(3) of the proposed AD.
    We agree with the commenter's request for the reason provided. We 
have clarified paragraphs (g)(2) and (g)(3) of this proposed AD to 
include the language provided by the commenter.

Request To Clarify Exceptions

    Boeing asked that we change paragraph (k)(3) of the proposed AD to 
clarify that the exception covers cracking found during any inspection 
required by paragraph (h) or (j)(1) of the proposed AD (in the NPRM). 
Boeing stated repairing any crack found during the inspection before 
installation of the preventative modification in paragraph (h) of the 
proposed AD (in the NPRM) should also be an exception.
    We do not agree with the commenter's request. Paragraph (j) of this 
proposed AD (which was referred to as paragraph (i) of the proposed AD 
(in the NPRM)) already specifies repairing any cracking found during 
any inspection required by paragraph (i) of this proposed AD (which was 
referred to as paragraph (h) of the proposed AD (in the NPRM)), as well 
as inspections required by paragraphs (g)(1), (g)(2), and (g)(3) of 
this proposed AD. Paragraph (k)(3) of the proposed AD (in the NPRM) was 
intended to address cracking found during the preventative modification 
specified in paragraph (j)(1) of the proposed AD (in the NPRM). For 
clarity in this proposed AD, we have added the corrective action for 
cracking found during the inspection specified in paragraph (k)(1) of 
this proposed AD (which was referred to as paragraph (j)(1) of the 
proposed AD (in the NPRM)) into paragraph (k)(1) of this proposed AD. 
We have also removed paragraph (k)(3) of the proposed AD (in the NPRM) 
from this proposed AD.

Request To Clarify Certain AMOC Language

    Two commenters requested that we clarify whether existing AMOCs are 
approved. UA asked that paragraph (m)(4) of the proposed AD (in the 
NPRM) be changed to clarify that repairs approved previously as AMOCs 
to AD 2011-01-15 require no further evaluation or approval. UA stated 
that operators were required to repair any finding with a repair that 
included an AMOC to AD 2011-01-15. UA stated that the current language 
in paragraph (m)(4) of the proposed AD (in the NPRM) would invalidate 
all such AMOCs, forcing operators to submit new requests for approval 
for each previously approved repair. In addition, UA asked that we 
include a new paragraph (l)(3) to provide credit for inspections 
required by paragraph (g)(1) of the proposed AD (in the NPRM) that were 
approved as an AMOC to AD 2011-01-15.
    Boeing asked if paragraph (m)(4) of the proposed AD (in the NPRM) 
meant that new AMOCs are needed for all AMOCs to AD 2011-01-15. Boeing 
asked that credit be given for inspections required by paragraph (g)(1) 
of the proposed AD (in the NPRM) that were approved as an AMOC to AD 
2011-01-15 in Boeing Alternative Method of Compliance Notice 757-53-
0097-AMOC-01, dated March 28, 2011, and stated in FAA letter 120S-11-
13, dated January 19, 2011. Boeing stated that the AMOC allowed a 
longer interval for the inspections that are now incorporated in Boeing 
Special Attention Service Bulletin 757-53-0097, Revision 2, dated July 
28, 2015. Boeing also noted that Boeing Alternative Method of 
Compliance Notice 757-53-0097 AMOC 03, dated March 28, 2014, should be 
rescinded since new data shows that a 15,000 total flight cycle 
threshold is appropriate instead of 18,000 total flight cycles.
    We agree that clarification is necessary. Although paragraph (m)(4) 
of the proposed AD (in the NPRM) specified that AMOCs approved for AD 
2011-01-15, are not approved as AMOCs for the corresponding provisions 
of paragraph (g) of the proposed AD (in the NPRM); after further review 
we have determined those AMOCs should continue to be approved, except 
as of the effective date of this proposed AD, AMOCs that extend the 
initial compliance times specified in AD 2011-01-15 are no longer 
approved for the compliance time extension and instead, the compliance 
times required by this proposed AD must be complied with. Boeing 
Alternative Method of Compliance Notice 757-53-0097 AMOC 03, dated 
March 28, 2014, extended the initial compliance times specified in AD 
2011-01-15, and as stated previously, we have received new data that 
does not justify the extended compliance times. We have changed 
paragraph (n)(4) of this proposed AD (which was referred to as 
paragraph (m)(4) of the proposed AD (in the NPRM)) accordingly.
    Boeing asked that paragraph (m)(3) of the proposed AD (in the NPRM) 
be changed from ``For a repair method 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'' to ``For a repair method, modification deviation, or 
alteration deviation 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.'' 
Boeing stated that this approval needs to specify not only for a repair 
method to be approved, but also for modification and alteration 
deviations to be approved, they must meet type certification.
    We agree that some clarification is necessary. We have clarified 
paragraph (n)(3) of this proposed AD (which was referred to as 
paragraph (m)(3) of the proposed AD (in the NPRM)) as follows: ``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 Commercial Airplanes Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Los 
Angeles ACO, 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.''

Request To Correct Typographical Error

    Boeing asked that we change the punctuation following the word 
``repair'' in the first sentence of paragraph (m)(3) of the proposed AD 
(in the NPRM) from a period to a comma. Boeing noted that this is a 
punctuation error.
    We agree with the commenter's request and have corrected the

[[Page 21151]]

punctuation in paragraph (n)(3) of this proposed AD (which was referred 
to as paragraph (m)(3) of the proposed AD (in the NPRM)) accordingly.

Concerns About Correcting Unsafe Condition

    A commenter, Jonathan Fortune, stated that it is imperative that 
any potentially catastrophic structural issues identified in any 
airplanes be promptly corrected. Mr. Fortune added that repair costs 
are greatly outweighed by the potential marketing and industry disaster 
that would occur if these airplanes crashed. Mr. Fortune noted that 
Boeing should not be able to operate these airplanes without addressing 
these issues. Mr. Fortune stated that he is willing to pay for 
increased air travel costs in order to get the sense of safety 
established through compliance with this regulation.
    We acknowledge and appreciate the commenter's concerns. The FAA 
works to ensure that all unsafe conditions are addressed in a timely 
manner in accordance with FAA risk management policies that are 
designed to promote aviation safety.

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 accomplishing the actions specified in the 
service information described previously. 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-
3697.

Costs of Compliance

    We estimate that this proposed AD affects 652 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
            Action                   Labor cost              Parts cost             product         operators
----------------------------------------------------------------------------------------------------------------
Inspections (Zone 1)           2 work-hour x $85 per  $0......................  $170 per         $110,840 per
 [Retained actions from AD      hour = $170 per                                  inspection       inspection
 2011-01-15].                   inspection cycle.                                cycle.           cycle.
Inspections (Zones 2 and 3)    Up to 4 work-hours x   $0......................  Up to $340 per   Up to $221,680
 [new proposed action].         $85 per hour = Up to                             inspection       per inspection
                                $340 per inspection                              cycle.           cycle.
                                cycle.
Optional modification........  Up to 615 work-hours   Up to $26,496...........  Up to $78,771..  Up to
                                x $85 per hour = Up                                               $51,358,692.
                                to $52,275.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
a cost estimate for the on-condition actions specified in this proposed 
AD.
    We have received no definitive data that would enable us to provide 
a cost estimate for the optional replacement specified in this proposed 
AD.

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.

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

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) 
2011-01-15, Amendment 39-16572 (76 FR 1351, January 10, 2011), and 
adding the following new AD.

The Boeing Company: Docket No. FAA-2016-3697; Directorate Identifier 
2015-NM-143-AD.

(a) Comments Due Date

    We must receive comments by June 19, 2017.

[[Page 21152]]

(b) Affected ADs

    This AD replaces AD 2011-01-15, Amendment 39-16572 (76 FR 1351, 
January 10, 2011) (``AD 2011-01-15'').

(c) Applicability

    (1) This AD applies to The Boeing Company Model 757-200 and -300 
series airplanes, certificated in any category, as identified in 
Boeing Special Attention Service Bulletin 757-53-0097, Revision 3, 
dated December 2, 2016.
    (2) Installation of Supplemental Type Certificate (STC) 
ST01518SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/38B606833BBD98B386257FAA00602538?OpenDocument&Highlight=st01518se) 
does not affect the ability to accomplish the actions required by 
this AD. Therefore, for airplanes on which STC ST01518SE is 
installed, a ``change in product'' alternative method of compliance 
(AMOC) approval request is not necessary to comply with the 
requirements of 14 CFR 39.17.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of the initiation of fatigue 
cracking in the fuselage skin of the crown skin panel along locally 
thinned channels adjacent to the chem-milled steps. We are issuing 
this AD to detect and correct fatigue cracking of the fuselage skin 
of the crown skin panel, which could result in pressure venting and 
consequent rapid decompression of the airplane.

(f) Compliance

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

(g) Repetitive Inspections

    Do the applicable inspections required by paragraphs (g)(1), 
(g)(2), and (g)(3) of this AD.
    (1) For all airplanes: Within the compliance time specified in 
paragraph (h) of this AD, do the Zone 1 inspection specified in 
paragraph (g)(1)(i) or (g)(1)(ii) of this AD. Repeat the applicable 
Part 1 or Part 2 inspection thereafter at the applicable times 
specified in table 1 of paragraph 1.E., ``Compliance,'' of Boeing 
Special Attention Service Bulletin 757-53-0097, Revision 3, dated 
December 2, 2016. Accomplishing the preventative modification 
specified in paragraph (k)(1) of this AD or the replacement 
specified in paragraph (k)(2) of this AD terminates the inspections 
required by this paragraph.
    (i) Do an external sliding probe eddy current (EC) inspection 
for cracking of the crown skin panel in the applicable Zone 1 areas 
specified in, and in accordance with, Part 1 of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016.
    (ii) Do an external spot-probe-medium-frequency EC inspection 
for cracking of the crown skin panel in the applicable Zone 1 areas 
specified in, and in accordance with Part 2 of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016.
    (2) For airplanes on which any crack is found during any 
inspection required by paragraph (g)(1) of this AD; or any repair is 
installed that covers any portion of the Zone 1 inspection area 
specified in Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 3, dated December 2, 2016; or the optional Zone 1 
preventative modification specified in paragraph (k)(1) of this AD 
is installed: At the applicable time specified in table 2 of 
paragraph 1.E., ``Compliance,'' of Boeing Special Attention Service 
Bulletin 757-53-0097, Revision 3, dated December 2, 2016, except as 
required by paragraph (l)(1) of this AD: Do the Zone 2 inspection 
specified in paragraph (g)(2)(i) or (g)(2)(ii) of this AD. Repeat 
the applicable Part 4 or Part 5 inspection thereafter at the 
applicable times specified in table 2 of paragraph 1.E., 
``Compliance,'' of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016. Accomplishing the 
replacement specified in paragraph (k)(2) of this AD terminates the 
inspections required by this paragraph.
    (i) Do an external sliding probe EC inspection for cracking of 
the crown skin panel in the applicable Zone 2 areas specified in, 
and in accordance with, Part 4 of the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 757-53-0097, Revision 3, 
dated December 2, 2016.
    (ii) Do an external spot-probe-medium-frequency EC inspection 
for cracking of the crown skin panel in the applicable Zone 2 areas 
specified in, and in accordance with, Part 5 of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016.
    (3) For airplanes on which any crack is found during any 
inspection required by paragraph (g)(1) of this AD; or any repair is 
installed that covers any portion of the Zone 1 inspection area 
specified in Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 3, dated December 2, 2016; or the optional Zone 1 
preventative modification specified in paragraph (k)(1) of this AD 
is installed: At the applicable time specified in table 3 of 
paragraph 1.E., ``Compliance,'' of Boeing Special Attention Service 
Bulletin 757-53-0097, Revision 3, dated December 2, 2016, except as 
required by paragraph (l)(1) of this AD, do the Zone 3 inspection 
specified in paragraph (g)(3)(i) or (g)(3)(ii) of this AD. Repeat 
the applicable Part 6 or Part 7 inspection thereafter at the 
applicable times specified in table 3 of paragraph 1.E., 
``Compliance,'' of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016. Accomplishing the 
replacement specified in paragraph (k)(2) of this AD terminates the 
inspections required by this paragraph.
    (i) Do an external sliding probe EC inspection for cracking of 
the crown skin panel in the applicable Zone 3 areas specified in, 
and in accordance with, Part 6 of the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 757-53-0097, Revision 3, 
dated December 2, 2016.
    (ii) Do an external spot-probe-medium-frequency EC inspection 
for cracking of the crown skin panel in the applicable Zone 3 areas, 
specified in, and in accordance with, Part 7 of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016.

(h) Initial Compliance Time for Inspection Required by Paragraph (g)(1) 
of This AD

    Within the applicable compliance times specified in paragraphs 
(h)(1), (h)(2), (h)(3), and (h)(4) of this AD, whichever occurs 
latest: Do the initial inspection required by paragraph (g)(1) of 
this AD.
    (1) For all airplanes: Before the accumulation of 15,000 total 
flight cycles.
    (2) For airplanes on which an external sliding probe EC 
inspection for Zone 1, as specified in Boeing Special Attention 
Service Bulletin 757-53-0097, has been done as of the effective date 
of this AD: Within 620 flight cycles after accomplishing the most 
recent external sliding probe EC inspection for Zone 1.
    (3) For airplanes on which an external spot-probe-medium-
frequency EC inspection for Zone 1, as specified in Boeing Special 
Attention Service Bulletin 757-53-0097, has been done as of the 
effective date of this AD: Within 200 flight cycles after 
accomplishing the most recent external spot-probe-medium-frequency 
EC inspection for Zone 1.
    (4) For all airplanes: Within 200 flight cycles or 90 days after 
the effective date of this AD, whichever occurs first.

(i) Post-Preventive Modification Supplemental Inspections

    For airplanes on which a preventive modification has been 
installed as specified in Part 3 of the Accomplishment Instructions 
of Boeing Special Attention Service Bulletin 757-53-0097, Revision 
3, dated December 2, 2016: At the applicable time specified in table 
4 of paragraph 1.E., ``Compliance,'' of Boeing Special Attention 
Service Bulletin 757-53-0097, Revision 3, dated December 2, 2016; do 
eddy current and detailed inspections for cracking of the applicable 
areas of the fuselage skin of the doublers, triplers, and fillers of 
the preventive modification, in accordance with the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016. Repeat the inspection 
thereafter at the applicable times specified in table 4 of paragraph 
1.E., ``Compliance,'' of Boeing Special Attention Service Bulletin 
757-53-0097, Revision 3, dated December 2, 2016.

(j) Repair

    If any cracking is found during any inspection required by 
paragraph (g)(1), (g)(2), (g)(3), or (i) of this AD, repair before 
further flight using a method approved in accordance with the 
procedures specified in paragraph (n) of this AD. Doing the repair 
ends the repetitive inspections for the repaired area only.

[[Page 21153]]

(k) Optional Terminating Actions

    (1) Accomplishing the preventative modification, including doing 
high frequency EC open-hole inspections for cracking in the existing 
fastener holes, in accordance with Part 3 of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 757-53-
0097, Revision 3, dated December 2, 2016, except as required by 
paragraph (l)(2) of this AD, terminates the inspections required by 
paragraph (g)(1) of this AD, provided the preventative modification 
is done before further flight after accomplishing an inspection 
required by paragraph (g)(1) of this AD. If any cracking is found 
during any high frequency EC open-hole inspection, before further 
flight, repair using a method approved in accordance with the 
procedures specified in paragraph (n) of this AD.
    (2) Replacing the crown skin panel between station (STA) 297 and 
STA 439, and stringers S-4L and S-4R, in accordance with the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 757-53-0097, Revision 3, dated December 2, 2016, or using a 
method approved in accordance with the procedures specified in 
paragraph (n) of this AD, terminates the inspections required by 
paragraphs (g)(1), (g)(2), and (g)(3) of this AD.

(l) Exceptions to Service Information Specifications and Preventative 
Modification

    (1) Where Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 3, dated December 2, 2016, specifies a compliance time 
``after the Revision 2 date of this service bulletin,'' or ``after 
the Revision 3 date of this service bulletin,'' this AD requires 
compliance within the specified compliance time after the effective 
date of this AD.
    (2) Where Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 3, dated December 2, 2016, specifies to contact Boeing for 
repair instructions: Before further flight, repair using a method 
approved in accordance with the procedures specified in paragraph 
(n) of this AD.

(m) Credit for Previous Actions

    This paragraph provides credit for Zone 1 inspections required 
by paragraph (g)(1) of this AD, if those actions were performed 
before the effective date of this AD using Boeing Special Attention 
Service Bulletin 757-53-0097, dated November 22, 2010 (which was 
incorporated by reference in AD 2011-01-15); Boeing Special 
Attention Service Bulletin 757-53-0097, Revision 1, dated January 6, 
2011; or Boeing Special Attention Service Bulletin 757-53-0097, 
Revision 2, dated July 28, 2015.

(n) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office 
(ACO), 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 ACO, send it to the 
attention of the person identified in paragraph (o)(1) of this AD. 
Information may be emailed to: 9-ANM-LAACO-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 Commercial Airplanes Organization 
Designation Authorization (ODA) that has been authorized by the 
Manager, Los Angeles ACO, 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 for AD 2011-01-15 are approved as AMOCs for 
the corresponding provisions of paragraph (g) of this AD; except, as 
of the effective date of this AD, AMOCs that extend the initial 
compliance times specified in AD 2011-01-15 are no longer approved 
for the compliance time extension and the compliance times required 
by this AD must be complied with.
    (5) For service information that contains steps that are labeled 
as Required for Compliance (RC), the provisions of paragraphs 
(n)(5)(i) and (n)(5)(ii) apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. An AMOC is required for any deviations to RC steps, 
including substeps and identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(o) Related Information

    (1) For more information about this AD, contact Eric Schrieber, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5348; fax: 562-627-5210; email: Eric.Schrieber@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; 
telephone 562-797-1717; Internet https://www.myboeingfleet.com. You 
may view this referenced service information at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For 
information on the availability of this material at the FAA, call 
425-227-1221.

    Issued in Renton, Washington, on April 7, 2017.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2017-07938 Filed 5-4-17; 8:45 am]
BILLING CODE 4910-13-P