Document ID: FAA-2018-0504-0002
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2018-06-07T04:00Z

[Federal Register Volume 83, Number 110 (Thursday, June 7, 2018)]
[Proposed Rules]
[Pages 26383-26387]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-12128]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0504; Product Identifier 2018-NM-046-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for all 
The Boeing Company Model 707 series airplanes and Model 720 and 720B 
series airplanes. This proposed AD was prompted by a report indicating 
that a fracture of the midspar fitting resulted in the separation of 
the inboard strut and engine from the airplane, and a determination 
that existing inspections are not sufficient for timely detection of 
cracking. This proposed AD would require repetitive inspections of 
certain nacelle strut spar and overwing fittings, and diagonal braces 
and associated fittings; replacement of the diagonal brace assembly on 
certain airplanes; and applicable related investigative and corrective 
actions. We are proposing

[[Page 26384]]

this AD to address the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by July 23, 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: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; 
telephone 562-797-1717; internet https://www.myboeingfleet.com. You may 
view this service information at the FAA, Transport Standards Branch, 
2200 South 216th St., Des Moines, WA. 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-2018-0504.

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-2018-
0504; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this NPRM, 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: Jeffrey Chang, Aerospace Engineer, 
Propulsion Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5263; fax: 562-627-
5210; email: [email protected] or George Garrido, Aerospace 
Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5232; fax: 562-627-
5210; email [email protected].

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-2018-0504; 
Product Identifier 2018-NM-046-AD'' at the beginning of your comments. 
We specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this NPRM. We will consider all 
comments received by the closing date and may amend this NPRM 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 NPRM.

Discussion

    We have received reports of cracking of the midspar fittings and of 
the engine and nacelle strut separating from the airplane. We issued AD 
2012-16-12, Amendment 39-16159 (77 FR 49708, August 17, 2012) to 
require inspection of the inboard and outboard strut midspar fittings 
and AD 2015-11-04, Amendment 39-18167 (80 FR 30605, May 29, 2015) to 
require replacement of all engine strut midspar fittings and to 
initiate a life limit program. Since that time, we have determined that 
inspections of other strut fittings are needed for timely detection of 
cracking. Cracks have been reported in the diagonal brace end fittings, 
forward mating fittings, aft mating fittings, overwing support 
fittings, and the upper surface and the aft lug(s) of the front spar 
fittings on the nacelle struts, numbers 1, 2, 3 and 4. This cracking is 
attributed to fatigue in the end fittings and stress corrosion or 
fatigue in the mating fittings. This condition, if not addressed, could 
result in cracks that grow beyond a critical length, allowing strut 
fittings to fail and reducing the structural integrity of the nacelle. 
This, in combination with damage to adjacent attachment structure, 
could result in the loss of an engine from the airplane.

Related Service Information Under 1 CFR Part 51

    We reviewed the following service information.
     Boeing 707 Alert Service Bulletin A3364, Revision 4, dated 
February 21, 2017. The service information describes procedures for 
repetitive detailed inspections of the diagonal brace tube for any 
crack; repetitive detailed inspections and high frequency eddy current 
(HFEC) inspections of the nacelle strut diagonal brace end fittings, 
forward mating fitting, and aft mating fitting for any crack; an 
alternative dye penetrant inspection of vertical webs on aft mating 
fitting for any crack; an HFEC inspection of the diagonal brace tube 
for any crack; and corrective actions.
     Boeing 707 Alert Service Bulletin A3365, Revision 3, dated 
March 9, 2017. The service information describes procedures for 
repetitive detailed, HFEC, and ultrasonic inspections of the overwing 
support fittings for any crack at the bolt hole forward of the wing 
front spar and at the holes for the four fasteners attaching the 
fitting to the spar, and related investigative and corrective actions.
     Boeing 707 Alert Service Bulletin A3514, Revision 1, dated 
November 9, 2016. The service information describes procedures for 
repetitive detailed and surface HFEC inspections of the front spar 
fittings at nacelle struts numbers 1, 2, 3, and 4 for cracks, and 
replacement of cracked front spar fittings.
    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 these same type 
designs.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified 
in the service information described previously, except as discussed 
under ``Differences Between this Proposed AD and the Service 
Information.'' 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-2018-0504.
    The phrase ``related investigative actions'' is used in this 
proposed AD. Related investigative actions are follow-on actions that 
(1) are related to the primary action, and (2) further investigate the 
nature of any condition found. Related investigative actions in an AD 
could include, for example, inspections.
    The phrase ``corrective actions'' is used in this proposed AD. 
Corrective actions correct or address any condition found. Corrective 
actions in an AD could include, for example, repairs.

[[Page 26385]]

Differences Between This Proposed AD and the Service Information

    Boeing 707 Alert Service Bulletin A3364, Revision 4, dated February 
21, 2017; Boeing 707 Alert Service Bulletin A3365, Revision 3, dated 
March 9, 2017; and Boeing 707 Alert Service Bulletin A3514, Revision 1, 
dated November 9, 2016; specify to contact the manufacturer for certain 
instructions, but this proposed AD would require using repair methods, 
modification deviations, replacement deviations, and alteration 
deviations in one of the following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by the Boeing Commercial 
Airplanes Organization Designation Authorization (ODA) whom we have 
authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD affects 65 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
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                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Detailed inspections per Service   36 work-hours x $85              $0  $3,060 per           $198,900 per
 Bulletin A3364, Revision 4.        per hour = $3,060                    inspection cycle.    inspection cycle.
                                    per inspection
                                    cycle.
HFEC inspections per Service       128 work-hours x                  0  $10,880 per          $707,200 per
 Bulletin A3364, Revision 4.        $85 per hour =                       inspection cycle.    inspection cycle.
                                    $10,880 per
                                    inspection cycle.
Inspections per Service Bulletin   20 work-hours x $85               0  $1,700 per           $110,500 per
 A3365, Revision 3.                 per hour = $1,700                    inspection cycle.    inspection cycle.
                                    per inspection
                                    cycle.
Detailed inspections per Service   12 work-hours x $85               0  $1,020 per           $66,300 per
 Bulletin A3514, Revision 1.        per hour = $1,020                    inspection cycle.    inspection cycle.
                                    per inspection
                                    cycle.
HFEC inspections per Service       32 work-hours x $85               0  $2,720 per           $176,800 per
 Bulletin A3514, Revision 1.        per hour = $2,720                    inspection cycle.    inspection cycle.
                                    per inspection
                                    cycle.
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    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions specified in this proposed 
AD.
    We estimate that any necessary proposed replacement of affected 
fittings would take about 96 work-hours for a cost of $8,160 per 
fitting. We have received no definitive data on the parts costs of the 
affected fittings. We have no way of determining the number of aircraft 
that might need this replacement.

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 and associated appliances 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

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 (AD):

The Boeing Company: Docket No. FAA-2018-0504; Product Identifier 
2018-NM-046-AD.

(a) Comments Due Date

    We must receive comments by July 23, 2018.

(b) Affected ADs

    This AD affects AD 82-24-03, Amendment 39-4496 (47 FR 51099, 
November 12, 1982) (``AD 82-24-03'') and AD 2005-08-15, Amendment 
39-14067 (70 FR 21136, April 25, 2005) (``AD 2005-08-15'').

(c) Applicability

    This AD applies to all The Boeing Company Model 707-100 Long 
Body, -200, -100B Long Body, and -100B Short Body series airplanes; 
Model 707-300, -300B, -300C, and -400 series airplanes; and Model 
720 and 720B series airplanes; certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 54, Nacelles/
pylons.

[[Page 26386]]

(e) Unsafe Condition

    This AD was prompted by a report indicating that a fracture of 
the midspar fitting resulted in the separation of the inboard strut 
and engine from the airplane, and a determination that existing 
inspections for other nacelle strut fittings are not sufficient for 
timely detection of cracking. We are issuing this AD to address 
cracks, which if not detected and corrected, could grow beyond a 
critical length, allowing the strut fitting to fail and reducing the 
structural integrity of the nacelle. This, in combination with 
damage to adjacent attachment structure, could result in the loss of 
an engine from the airplane.

(f) Compliance

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

(g) Repetitive Detailed Inspections of the Front Spar Fittings at 
Nacelle Struts Numbers 1, 2, 3, and 4

    Prior to the accumulation of 3,500 total flight hours; within 
700 flight hours after the most recent inspection specified in 
Boeing 707 Alert Service Bulletin A3514, dated July 29, 2004, was 
done; or within three months after the effective date of this AD; 
whichever occurs later: Do a detailed inspection for cracking of the 
front spar fittings at nacelle struts numbers 1, 2, 3, and 4, in 
accordance with the Accomplishment Instructions of Boeing 707 Alert 
Service Bulletin A3514, Revision 1, dated November 9, 2016. If any 
cracking is found, before further flight, replace the affected 
fitting, in accordance with the Accomplishment Instructions of 
Boeing 707 Alert Service Bulletin A3514, Revision 1, dated November 
9, 2016. Repeat the inspections thereafter at intervals not to 
exceed 700 flight hours.

(h) Repetitive Surface High Frequency Eddy Current (HFEC) Inspections 
of the Aft Lugs on the Front Spar Fittings at Nacelle Struts Numbers 1, 
2, 3, and 4

    Within 1,500 flight cycles or 48 months after the most recent 
detailed inspection required by paragraph (g) of this AD was done, 
whichever occurs first, do a surface HFEC inspection for cracking of 
the aft lugs on the front spar fittings at nacelle struts numbers 1, 
2, 3, and 4, and do all applicable corrective actions, in accordance 
with the Accomplishment Instructions of Boeing 707 Alert Service 
Bulletin A3514, Revision 1, dated November 9, 2016, except as 
required by paragraph (l)(4) of this AD. Do all applicable 
corrective actions before further flight. Repeat the inspection 
thereafter at intervals not to exceed 1,500 flight cycles or 48 
months, whichever occurs first.

(i) Repetitive Inspections of the Overwing Support Fitting at Nacelle 
Struts Numbers 1, 2, 3, and 4

    At the times specified in paragraph 1.E., ``Compliance,'' of 
Boeing 707 Alert Service Bulletin A3365, Revision 3, dated March 9, 
2017, except as required by paragraph (l)(1) of this AD: Do the 
inspections specified in paragraphs (i)(1) through (i)(3) of this AD 
and do all applicable related investigative and corrective actions, 
in accordance with the Accomplishment Instructions of Boeing 707 
Alert Service Bulletin A3365, Revision 3, dated March 9, 2017, 
except as required by paragraph (l)(3) of this AD. Do all applicable 
related investigative and corrective actions before further flight. 
Repeat the inspections thereafter at the applicable time specified 
in paragraph 1.E., ``Compliance,'' of Boeing 707 Alert Service 
Bulletin A3365, Revision 3, dated March 9, 2017.
    (1) Do a detailed inspection for any crack at all five holes in 
the overwing support fitting, and at the flange radii.
    (2) Do the inspection specified in paragraph (i)(2)(i) or 
(i)(2)(ii) of this AD.
    (i) Do a surface HFEC inspection for any crack in the overwing 
support fitting around the hole immediately forward of the spar 
chord, with the bolt in place, and at the flange radii.
    (ii) Do an open hole HFEC inspection for any crack in the 
overwing support fitting at the hole immediately forward of the spar 
chord.
    (3) Do the inspection specified in paragraph (i)(3)(i) or 
(i)(3)(ii) of this AD.
    (i) Do an ultrasonic inspection for any crack in the overwing 
support fitting around the four holes common to the fitting and the 
spar chord, with the bolts in place.
    (ii) Do a surface HFEC inspection for any crack in the overwing 
support fitting around the four holes common to the fitting and the 
spar chord, with the bolts in place.

(j) Inspections of the Nacelle Strut Diagonal Braces and Associated 
Fittings

    For airplanes with nacelle strut diagonal braces and associated 
fittings which have accumulated 7,500 flight cycles or more: At the 
applicable times specified in paragraph 1.E., ``Compliance'' of 
Boeing 707 Alert Service Bulletin A3364, Revision 4, dated February 
21, 2017, except as required by paragraph (l)(2) of this AD, do the 
inspections specified in paragraphs (j)(1) through (j)(3) of this 
AD. Repeat the inspections thereafter at the applicable intervals 
specified in tables 1, 2, 3, and 4 of paragraph 1.E., 
``Compliance,'' of Boeing 707 Alert Service Bulletin A3364, Revision 
4, dated February 21, 2017. If any crack is found during any 
inspection required by this paragraph, before further flight, do all 
applicable corrective actions, in accordance with the Accomplishment 
Instructions of Boeing 707 Alert Service Bulletin A3364, Revision 4, 
dated February 21, 2017, except as required by paragraph (l)(3) of 
this AD.
    (1) Do a detailed inspection of the nacelle strut diagonal brace 
end fittings, diagonal brace tube, forward mating fitting, and aft 
mating fitting for any crack.
    (2) Do HFEC inspections of the nacelle strut diagonal brace end 
fittings, forward mating fitting, and aft mating fitting for any 
crack. As an alternative for the aft mating fitting, do a dye 
penetrant inspection of vertical webs on aft mating fitting for any 
crack.
    (3) Do an HFEC inspection of the diagonal brace tube for any 
crack.

(k) Replacement

    For Group 3, 4, and 6 airplanes as identified in Boeing 707 
Alert Service Bulletin A3364, Revision 4, dated February 21, 2017, 
on which the outboard diagonal brace end fitting (forward or aft) 
attach holes have been oversized as specified in Boeing 707 Alert 
Service Bulletin A3364, Revision 4, dated February 21, 2017: Within 
1,000 flight cycles after the effective date of this AD, replace the 
diagonal brace assembly, in accordance with Figure 3 of Boeing 707 
Alert Service Bulletin A3364, Revision 4, dated February 21, 2017.

(l) Exceptions to Service Information Specifications

    (1) For purposes of determining compliance with the requirements 
of this AD: Where Boeing 707 Alert Service Bulletin A3365, Revision 
3, dated March 9, 2017, uses the phrase ``the Revision 3 date of 
this service bulletin,'' this AD requires using ``the effective date 
of this AD.''
    (2) For purposes of determining compliance with the requirements 
of this AD: Where Boeing 707 Alert Service Bulletin A3364, Revision 
4, dated February 21, 2017, uses the phrase ``the Revision 4 date of 
this service bulletin,'' this AD requires using ``the effective date 
of this AD.''
    (3) Where Boeing 707 Alert Service Bulletin A3364, Revision 4, 
dated February 21, 2017; and Boeing 707 Alert Service Bulletin 
A3365, Revision 3, dated March 9, 2017; specify contacting Boeing: 
This AD requires repair using a method approved in accordance with 
the procedures specified in paragraph (o) of this AD.
    (4) Where Boeing 707 Alert Service Bulletin A3514, Revision 1, 
dated November 9, 2016, specifies contacting Boeing: This AD 
requires replacement using a method approved in accordance with the 
procedures specified in paragraph (o) of this AD.

(m) Terminating Action for Other ADs

    (1) Accomplishing the initial inspections required by paragraph 
(j) of this AD terminates all requirements of AD 82-24-03.
    (2) Accomplishing the initial inspections required by paragraph 
(g) of this AD, terminates all requirements of AD 2005-08-15.

(n) Parts Installation Prohibition

    As of the effective date of this AD, no person may install, on 
any airplane, a front spar fitting having a part number other than 
the part numbers specified in paragraph 2.C.2. of Boeing 707 Alert 
Service Bulletin A3514, Revision 1, dated November 9, 2016.

(o) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles ACO Branch, FAA, has the authority 
to approve AMOCs for this AD, if requested using the procedures 
found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your 
request to your principal inspector or local Flight Standards 
District Office, as appropriate. If sending information directly to 
the manager of the certification office, send it to the attention of 
the person(s) identified in paragraph (p)(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

[[Page 26387]]

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, replacement, 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 Branch, to make those 
findings. To be approved, the repair method, modification deviation, 
replacement deviation, or alteration deviation must meet the 
certification basis of the airplane, and the approval must 
specifically refer to this AD.

(p) Related Information

    (1) For more information about this AD, contact Jeffrey Chang, 
Aerospace Engineer, Propulsion Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5263; fax: 562-627-5210; email: [email protected] or George 
Garrido, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO 
Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 
562-627-5232; fax: 562-627-5210; email [email protected].
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; internet https://www.myboeingfleet.com. 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.

    Issued in Des Moines, Washington, on May 24, 2018.
James Cashdollar,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2018-12128 Filed 6-6-18; 8:45 am]
BILLING CODE 4910-13-P