Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 80, Number 103 (Friday, May 29, 2015)]
[Rules and Regulations]
[Pages 30605-30608]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-12858]



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Federal Register / Vol. 80, No. 103 / Friday, May 29, 2015 / Rules 
and Regulations

[[Page 30605]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2014-0756; Directorate Identifier 2014-NM-103-AD; 
Amendment 39-18167; AD 2015-11-04]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for all The 
Boeing Company Model 707 airplanes, and Model 720 and 720B series 
airplanes. This AD was prompted by reports of cracked midspar fittings 
on the inboard and outboard nacelle struts. This AD requires 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 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 wing fire.

DATES: This AD is effective July 6, 2015.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 6, 
2015.

ADDRESSES: 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. It is also available on the Internet at http://regulations.gov by searching for and locating Docket No. FAA-2014-0756.

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 AD, the regulatory evaluation, any comments received, and 
other information. The address for the Docket Office (phone: 800-647-
5527) is Docket Management Facility, U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue SE., Washington, DC 20590.

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: [email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to all The Boeing Company 
Model 707 airplanes, and Model 720 and 720B series airplanes. The NPRM 
published in the Federal Register on November 13, 2014 (79 FR 67379). 
The NPRM was prompted by reports of cracked midspar fittings on the 
inboard and outboard nacelle struts. The NPRM proposed to 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 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 wing fire.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM (79 
FR 67379, November 13, 2014) and the FAA's response to each comment.

Request To Extend the Compliance Time

    The Air Force Life Cycle Management Center (AFLCMC) at Robins Air 
Force Base, and the Massachusetts Institute of Technology Lincoln 
Laboratory Flight Facility (LLFF), requested that the compliance time 
proposed in the NPRM (79 FR 67379, November 13, 2014) be extended. 
AFLCMC asked that the grace period be extended from 18 months after the 
effective date of the AD to 24 months after the effective date of the 
AD. This commenter explained that its airplanes are scheduled for heavy 
maintenance visits every 24 months, and the 18-month grace period for 
the initial actions proposed in the NPRM would negatively impact 
airplane availability.
    In addition, the AFLCMC stated that there is a low quantity of kits 
available to replace the inboard and outboard midspar fittings with new 
parts, as proposed in paragraphs (g) and (h) of the NPRM (79 FR 67379, 
November 13, 2014). This commenter also noted that the kits are 
expensive and have long lead times, which could impact operators' 
schedules. We infer that the commenter is requesting that the 
compliance time proposed in the NPRM be lengthened to accommodate parts 
availability.
    LLFF's interpretation of the compliance time was that the 
compliance time was related to the date of the service bulletin. LLFF 
commented that operators would have a difficult time complying with the 
requirements proposed in the NPRM (79 FR 67379, November 13, 2014).
    We do not agree with the commenters' requests to extend the 
compliance time.

[[Page 30606]]

In developing an appropriate compliance time for this action, we 
considered not only the degree of urgency associated with addressing 
the subject unsafe condition, but the manufacturer's recommendation for 
an appropriate compliance time, the availability of required parts, and 
the practical aspect of installing the required modification within an 
interval of time that corresponds to the typical scheduled maintenance 
for the majority of affected operators. The supplier of the parts kits 
reports that the lead time for kit delivery is 12 months from the date 
an operator places an order. This final rule provides operators with a 
grace period of 18 months from the effective date of this AD, which we 
deem adequate for acquiring the midspar fitting kits, performing the 
inspection, accomplishing any necessary corrective actions, and 
replacing the midspar fittings. However, under the provisions of 
paragraph (k) of this AD, we may approve requests for adjustments to 
the compliance time if data are submitted to substantiate that such an 
adjustment would provide an acceptable level of safety. We have not 
changed this final rule regarding this issue.

Request To Clarify the Unsafe Condition

    Boeing requested that the unsafe condition statement in the NPRM 
(79 FR 67379, November 13, 2014) be revised. The NPRM stated ``This 
condition could cause an unsafe separation of the engine and consequent 
wing fire.'' Boeing commented that the word ``consequent'' implied that 
the end result would always be a wing fire. Boeing suggested that the 
wording be changed to ``This condition could cause an unsafe separation 
of the engine and potential fire.''
    We do not agree to revise the unsafe condition statement in this 
final rule. Where the unsafe condition states ``could result'' it is 
recognized that the loss of structural integrity, unsafe separation of 
the engine, and wing fire are possible outcomes in a chain of events. 
Furthermore, we frequently use ``consequent'' in unsafe condition 
statements when we state the end-level effect of the unsafe condition 
on an airplane. We have not changed this AD regarding this issue.

Request To Revise the Discussion Section of the NPRM (79 FR 67379, 
November 13, 2014)

    Boeing requested that the term limit of validity (LOV) in the first 
paragraph of the Discussion section of the preamble of the NPRM (79 FR 
67379, November 13, 2014) be removed because it is misleading. Boeing 
commented that the term LOV has implications associated with it which 
may not be intended. Boeing suggested that the term ``service 
objective'' be used instead of LOV.
    We agree that the unsafe condition addressed by this final rule is 
not related to an airplane reaching its LOV. The actions in this final 
rule are necessary to prevent loss of the structural integrity of the 
midspar fitting as the result of stress corrosion and fatigue at the 
lug and fatigue at the tangs. These actions do not directly support an 
airplane reaching its LOV. The Discussion section from the preamble of 
an NPRM is not repeated in a final rule so no change is necessary. We 
have revised paragraph (e) of this AD by removing the statement ``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 
replaced that statement with ``This AD was prompted by reports of 
cracked midspar fittings on the inboard and outboard nacelle struts.''

Request To Clarify Replacement Requirements

    Rafael Veas stated that two midspar fittings had already been 
replaced on an airplane at his facility. This commenter asked if all 
four midspar fittings have to be replaced, or only the two remaining 
midspar fittings that have not yet been replaced.
    We agree to clarify the replacement requirements of this final 
rule. Paragraph (f) of this AD states ``Comply with this AD within the 
compliance times specified, unless already done.'' The two midspar 
fittings that have already been replaced do not have to be replaced 
again if they have been replaced in accordance with the procedures 
mandated by this AD. For these two midspar fittings the repetitive 
inspection and replacement intervals should be calculated from the most 
recent midspar fitting replacement. We have not changed this final rule 
regarding this issue.

Request To Revise the Cost Estimate

    The AFLCMC mentioned that the cost and labor estimates presented in 
the preamble of the NPRM (79 FR 67379, November 13, 2014) are 
significantly lower than the actual costs. The commenter stated that 
accomplishment of the actions proposed in the NPRM would require a set 
of ready-for-installation engine pylons, removal of all four engines, 
inspections, and reassembly, and the estimated cost would be over 
$1,000,000 per airplane. We infer that the commenter requested that the 
estimated costs be revised.
    After considering the data presented by the commenter, we agree 
that the cost and labor estimates referenced in the NPRM (79 FR 67379, 
November 13, 2014) are significantly lower than the actual costs. The 
cost estimate in the NPRM was for replacement of the midspar fitting 
for one engine, and the proposed requirement in the NPRM was for 
replacement of the midspar fitting for all four engines. The estimated 
cost information in this final rule has been revised to indicate this 
higher amount. We disagree, however, with the commenter's estimate that 
the cost will be over $1,000,000 per airplane. Our cost estimate 
includes the work hours and parts cost for the required midspar fitting 
replacements, but does not include costs associated with maintenance 
scheduling or a set of ready-for-installation engine pylons.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM (79 FR 67379, November 13, 2014) for correcting the unsafe 
condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM (79 FR 67379, November 13, 2014).

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing 707 Alert Service Bulletin A3183, Revision 6, 
dated February 7, 2014. The service information describes procedures 
for 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 related 
investigative and corrective actions; replacing the midspar fittings; 
and doing other specified actions. This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section of this AD.

Costs of Compliance

    We estimate that this AD affects 12 airplanes of U.S. registry.

[[Page 30607]]

    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                   Cost on U.S.
            Action                  Labor cost            Parts cost         Cost per product       operators
----------------------------------------------------------------------------------------------------------------
Inspections..................  214 work-hours x $85  $0..................  $72,760 (4 pylons     $873,120 per
                                per hour = $18,190                          per inspection        inspection
                                per pylon per                               cycle).               cycle.
                                inspection cycle.
Replacement of midspar         18 work-hours x $85   Up to $7,867........  Up to $37,588 (1      Up to $451,056.
 fitting.                       per hour = $1,530                           fitting per pylon,
                                per pylon.                                  4 pylons total).
Mid-interval inspections.....  107 work-hours x $85  $0..................  $36,380 (4 pylons     $436,560 per
                                per hour = $9,095                           per inspection        inspection
                                per pylon per                               cycle).               cycle.
                                inspection cycle.
----------------------------------------------------------------------------------------------------------------

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

                                               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

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under 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.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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):

2015-11-04 The Boeing Company: Amendment 39-18167; Docket No. FAA-
2014-0756; Directorate Identifier 2014-NM-103-AD.

(a) Effective Date

    This AD is effective July 6, 2015.

(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 reports of cracked midspar fittings on 
the inboard and outboard nacelle struts. 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 wing 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 707 Alert Service Bulletin A3183, Revision 6, dated 
February 7, 2014, except as required by

[[Page 30608]]

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 707 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 707 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 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 
(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 (l) 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 
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

    For more information about this AD, contact Chandra Ramdoss, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5239; fax: 562-627-5210; email: [email protected].

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing 707 Alert Service Bulletin A3183, Revision 6, dated 
February 7, 2014.
    (ii) Reserved.
    (3) 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.
    (4) 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on May 20, 2015.
John P. Piccola, Jr.,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2015-12858 Filed 5-28-15; 8:45 am]
 BILLING CODE 4910-13-P

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