Document ID: FAA-2014-0756-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2014-11-13T05:00Z

[Federal Register Volume 79, Number 219 (Thursday, November 13, 2014)]
[Proposed Rules]
[Pages 67379-67382]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-26837]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2014-0756; Directorate Identifier 2014-NM-103-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 airplanes, and Model 720 and 720B series 
airplanes. This proposed AD is intended to complete certain mandated 
programs intended to support the airplane reaching its limit of 
validity (LOV) of the engineering data that support the established 
structural maintenance program. This proposed AD would require 
repetitive inspections for cracking of the inboard and outboard midspar 
fittings of the nacelle struts and of the torque bulkhead, midspar 
chords, drag fitting, and front spar support, and doing applicable 
related investigative and corrective actions; replacing the midspar 
fittings; and doing other specified actions. We are proposing this AD 
to detect and correct cracking in the midspar fittings of the inboard 
and outboard nacelle struts, which could result in the loss of the 
structural integrity of the midspar fitting. This condition could cause 
an unsafe separation of the engine and consequent wing fire.

DATES: We must receive comments on this proposed AD by December 29, 
2014.

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 proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; 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.

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-2014-
0756; 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: Chandra Ramdoss, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 
562-627-5239; fax: 562-627-5210; email: chandraduth.ramdoss@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-2014-0756; 
Directorate Identifier 2014-NM-103-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

    As described in FAA Advisory Circular 120-104 (http://www.faa.gov/documentLibrary/media/Advisory_Circular/120-104.pdf), several programs 
have been developed to support initiatives that will ensure the 
continued airworthiness of aging airplane structure. The last element 
of those initiatives is the requirement to establish a limit of 
validity (LOV) of the engineering data that support the structural 
maintenance program under 14 CFR 26.21. This proposed AD is the result 
of an assessment of the previously established programs by Boeing 
during the process of establishing the LOV for Model 707 airplanes and 
Model 720 and 720B series airplanes. The actions specified in this 
proposed AD are necessary to complete certain programs to ensure the 
continued airworthiness of aging airplane structure and to support an 
airplane reaching its LOV.
    We received reports of cracked midspar fittings on the inboard and 
outboard nacelle struts. The airplanes had accumulated between 9,900 
and 63,000 total flight hours. Five of these airplanes had cracked 
midspar fittings that resulted in separation of the inboard strut and 
engine from the airplane inflight. In two of those events the inboard 
nacelle strut contacted the outboard engine, causing it to separate 
from the airplane. Operators have also reported cracking in the 
transition radius of the inboard and outboard midspar fittings of the 
nacelle struts of the numbers 1 and 4 engines.
    The reported cracks on the inboard and outboard midspar fittings of 
the nacelle struts of engines numbers 1, 2, 3, and 4 were found to be 
vertical at the

[[Page 67380]]

lug hole or across the double horizontal tangs at the radius where the 
tangs merge with the lug. Analysis determined that the 4330 steel 
midspar fittings cracked as a result of stress corrosion and fatigue at 
the lug and fatigue at the tangs.
    Cracked midspar fittings, if not detected and corrected, could 
result in the loss of the structural integrity of the midspar fitting. 
This condition could cause an unsafe separation of the engine and 
consequent wing fire.

Relevant Service Information

    We reviewed Boeing 707 Alert Service Bulletin A3183, Revision 6, 
dated February 7, 2014. 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-2014-
0756.

Related Rulemaking

    AD 93-11-02, Amendment 39-8594, Docket No. 92-NM-230-AD, which 
applies to The Boeing Company Model 707 and 720 series airplanes, 
requires repetitive inspections for cracking of the midspar fittings on 
the inboard struts, related investigative and corrective actions if 
necessary, and replacement of the midspar fittings with new, improved 
fittings, which constitutes terminating action for the repetitive 
inspections.
    AD 2012-16-12, Amendment 39-17159 (77 FR 49708, August 17, 2012), 
which applies to The Boeing Company Model 707 airplanes, and Model 720 
and 720B series airplanes, requires a detailed inspection of the 
midspar fittings of the nacelle struts for engine numbers 2 and 3 to 
confirm that the correct part number is installed, and installing the 
correct part number if it is not installed. The correct part number is 
the new, improved midspar fitting required by AD 93-11-02, Amendment 
39-8594, Docket No. 92-NM-230-AD. AD 2012-16-12 also requires 
repetitive high frequency eddy current inspections (HFEC) of the 
midspar fittings of engine numbers 2 and 3 nacelle struts for cracks 
and repair if necessary. In addition, AD 2012-16-12 requires repetitive 
general visual inspections of the nacelle struts of engine numbers 1, 
2, 3, and 4 to verify that the nacelle strut has not drooped below its 
normal position, and repair if necessary.

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.

Proposed AD Requirements

    This proposed AD would require accomplishing the inspections for 
cracking of the inboard and outboard midspar fittings of the nacelle 
struts and of the torque bulkhead, midspar chords, drag fitting, and 
front spar support, and doing applicable related investigative and 
corrective actions; replacing the midspar fittings; and doing other 
specified actions; as specified in parts 2 through 6, inclusive, of the 
Accomplishment Instructions of the service information described 
previously, except as discussed under ``Differences Between this 
Proposed AD and the Service Information.''
    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 actions, 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'' are actions that correct or address any 
condition found. Corrective actions in an AD could include, for 
example, repairs.
    The phrase ``other specified actions'' is used in this proposed AD. 
Other specified actions in this proposed AD include installing new 
inboard and outboard midspar fittings, installing oversized fasteners 
in the two forward most fastener holes common to the inboard side of 
the nacelle strut overwing support fitting and the wing front spar 
upper chord, applying sealant to the midspar area, and applying 
corrosion inhibiting compound to the midspar fitting areas.
    We have determined that the actions specified in table 1 of 
paragraph 1.E., ``Compliance,'' of Boeing 707 Alert Service Bulletin 
A3183, Revision 6, dated February 7, 2014, should not be required in 
this AD, as noted in the service bulletin.

Differences Between This Proposed AD and the Service Information

    Boeing 707 Alert Service Bulletin A3183, Revision 6, dated February 
7, 2014, specifies to contact the manufacturer for fitting installation 
instructions and instructions on how to repair certain conditions, but 
this proposed AD would require doing those corrective actions 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 12 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Action                        Labor cost                   Parts cost                 Cost per  product          Cost on U.S.  operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspections.......................  214 work-hours x $85 per    $0..........................  $18,190.....................  $218,280.
                                     hour = $18,190 per
                                     inspection cycle.
Replacement of midspar fitting....  18 work-hours x $85 per     Up to $7,867................  Up to $9,397................  Up to $112,764.
                                     hour = $1,530.
Mid-interval inspections..........  107 work-hours x $85 per    $0..........................  $9,095......................  $109,140.
                                     hour = $9,095 per
                                     inspection cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any additional inspections 
that would be required based on the results of the proposed 
inspections. We have no way of determining the number of aircraft that 
might need these inspections:

[[Page 67381]]

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                  Action                                Labor cost                 Parts cost        product
----------------------------------------------------------------------------------------------------------------
Inspections...............................  Up to 21 work-hours x $85 per hour              $0           $1,785
                                             = $1,785.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition corrective actions specified in 
this 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 adding the following new airworthiness 
directive (AD):

    The Boeing Company: Docket No. FAA-2014-0756; Directorate 
Identifier 2014-NM-103-AD.

(a) Comments Due Date

    We must receive comments by December 29, 2014.

(b) Affected ADs

    None.

(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.

(e) Unsafe Condition

    This AD was prompted by certain mandated programs intended to 
support the airplane reaching its limit of validity (LOV) of the 
engineering data that support the established structural maintenance 
program. We are issuing this AD to detect and correct cracking in 
the midspar fittings of the inboard and outboard nacelle struts, 
which could result in the loss of the structural integrity of the 
midspar fitting. This condition could cause an unsafe separation of 
the engine and consequent engine fire.

(f) Compliance

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

(g) Inspections of Nacelle Struts and Surrounding Structure and 
Replacement of Inboard and Outboard Midspar Fittings

    At the applicable time specified in table 2 or table 3 of 
paragraph 1.E., ``Compliance,'' of Boeing 707 Alert Service Bulletin 
A3183, Revision 6, dated February 7, 2014, except as required by 
paragraph (i)(1) of this AD: Do the inspections required by 
paragraphs (g)(1), (g)(2), and (g)(3) of this AD in accordance with 
part 2 or part 3, as applicable, of the Accomplishment Instructions 
of Boeing Alert Service Bulletin A3183, Revision 6, dated February 
7, 2014, except as required by paragraph (i)(2) of this AD. Before 
further flight, do all applicable related investigative and 
corrective actions, replace the inboard and outboard midspar 
fittings with new parts, and do other specified actions (including 
installing new bushings and oversize fasteners) in accordance with 
part 2 or part 3, as applicable, of the Accomplishment Instructions 
of Boeing Alert Service Bulletin A3183, Revision 6, dated February 
7, 2014, except as required by paragraph (i)(2) of this AD. Repeat 
the inspections required by paragraphs (g)(1), (g)(2), and (g)(3) of 
this AD thereafter at the applicable intervals specified in table 2 
or table 3 of paragraph 1.E., ``Compliance,'' of Boeing 707 Alert 
Service Bulletin A3183, Revision 6, dated February 7, 2014, except 
as required by paragraph (i)(1) of this AD.
    (1) A detailed inspection and a high frequency eddy current 
inspection (HFEC) for cracks in the inboard and outboard midspar 
fittings of the nacelle struts.
    (2) Open hole HFEC inspections for cracks in the torque 
bulkhead, midspar chords, drag fitting, and front spar support.
    (3) A surface HFEC inspection of the front spar support for 
cracks.

(h) Mid-Interval Inspections and Replacement of Nacelle Strut Midspar 
Fittings

    At the applicable time specified in table 4 or 5 of paragraph 
1.E., ``Compliance,'' of Boeing 707 Alert Service Bulletin A3183, 
Revision 6, dated February 7, 2014: Do the inspections required by 
paragraphs (h)(1), (h)(2), and (h)(3) of this AD, in accordance with 
part 4 or part 5, as applicable, of the Accomplishment Instructions 
of Boeing Alert Service Bulletin A3183, Revision 6, dated February 
7, 2014, except as required by paragraph (i)(2) of this AD. Do all 
applicable related investigative, corrective, and other specified 
actions (including installing new bushings and oversize fasteners) 
before further flight. Repeat the inspections required by paragraphs 
(h)(1), (h)(2), and (h)(3) of this AD thereafter at the applicable 
intervals specified in table 4 or 5 of paragraph 1.E., 
``Compliance,'' of Boeing 707 Alert Service Bulletin A3183, Revision 
6, dated February 7, 2014. The threshold for the repetitive 
inspections required by paragraphs (h)(1), (h)(2), and (h)(3) of 
this AD is 1,500 flight cycles or 48 months, whichever occurs first, 
since the most recent midspar fitting replacement.
    (1) A detailed inspection and a surface HFEC inspection for 
cracks in the inboard

[[Page 67382]]

and outboard midspar fittings of the nacelle struts.
    (2) An open hole HFEC inspection for cracks in the drag fitting 
and front spar support.
    (3) A surface HFEC inspection for cracks in the front spar 
support.

(i) Exceptions to Service Information Specifications

    (1) Where Boeing 707 Alert Service Bulletin A3183, Revision 6, 
dated February 7, 2014, specifies a compliance time ``after the 
Revision 6 date of this service bulletin,'' this AD requires 
compliance within the specified compliance time after the effective 
date of this AD.
    (2) Where Boeing 707 Alert Service Bulletin A3183, Revision 6, 
dated February 7, 2014, specifies to contact Boeing for appropriate 
action: Do corrective actions before further flight using a method 
approved in accordance with the procedures specified in paragraph 
(k) of this AD.

(j) Special Flight Permit

    Special flight permits, as described in Section 21.197 and 
Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 
and 21.199), are not allowed.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office, 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 (l)(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 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. For a repair method to be approved, the repair 
must meet the certification basis of the airplane and the approval 
must specifically refer to this AD.

(l) Related Information

    (1) For more information about this AD, contact Chandra Ramdoss, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles 
Aircraft Certification Office (ACO), 3960 Paramount Boulevard, 
Lakewood, CA 90712-4137; phone: 562-627-5239; fax: 562-627-5210; 
email: chandraduth.ramdoss@faa.gov.
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; 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 November 5, 2014.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2014-26837 Filed 11-12-14; 8:45 am]
BILLING CODE 4910-13-P