```

[Federal Register Volume 77, Number 104 (Wednesday, May 30, 2012)]
[Proposed Rules]
[Pages 31762-31765]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-13039]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0490; Directorate Identifier 2012-NM-066-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

ACTION: Notice of proposed rulemaking (NPRM).

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

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 was prompted by reports of cracking of the 
midspar fittings, and of the engine and nacelle strut separating from 
the airplane. This proposed AD would require performing a detailed 
inspection of the midspar fittings of the nacelle strut to confirm that 
the correct part number is installed, and installing the correct part 
number if necessary; performing repetitive high frequency eddy current 
inspections (HFEC) of the midspar fittings of the nacelle strut for 
cracks, and repair if necessary; and

[[Page 31763]]

performing repetitive general visual inspections of the nacelle struts 
to verify that the nacelle strut has not drooped below its normal 
position, applying the droop stripe to the nacelle strut and sailboat 
fairing if necessary, and repair if necessary. We are proposing this AD 
to detect and correct cracking of the midspar fitting, which could 
result in separation of the nacelle strut and engine from the airplane 
while in flight, and consequent loss of controllability of the 
airplane.

DATES: We must receive comments on this proposed AD by July 16, 2012.

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, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; email me.boecom@boeing.com; 
Internet https://www.myboeingfleet.com. You may review copies of the 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue SW., Renton, Washington. 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; 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: Berhane Alazar, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
165501 Lind Avenue SW., Renton, WA 98057-3356; phone: (425) 917-6577; 
fax: (425) 917-6590; email: Berhane.Alazar@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-2012-0490; 
Directorate Identifier 2012-NM-066-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 have received reports of fatigue cracking of the midspar 
fittings, and the engine and nacelle strut separating from the 
airplane. Operators have reported that the cracking occurred on more 
than 40 airplanes with approximately 9,900 to 63,000 flight hours. In 
addition, there has been a report of the engine number 3 nacelle strut 
separating from the airplane and contacting the engine number 4 nacelle 
strut, which also separated from the airplane. This condition, if not 
corrected, could result in a fractured midspar fitting, which could 
cause a separation of the nacelle strut and engine from the airplane 
while in flight, resulting in loss of controllability of the airplane.

Relevant Service Information

    We reviewed Boeing 707 Alert Service Bulletin A3537, dated January 
30, 2012. That service information describes procedures for:
     Performing a detailed inspection of the midspar fittings 
of the engine number 2 and 3 nacelle struts to confirm that the correct 
part number is installed, and installing the correct part number if 
necessary.
     Performing HFEC inspections of the midspar fittings of the 
engine number 2 and 3 nacelle struts for cracks, and repairing if 
necessary.
     Performing 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, applying the 
droop stripe to the nacelle strut and sailboat fairing if necessary, 
and repairing if necessary.
    The initial compliance times for the HFEC and general visual 
inspections, and the application of the droop stripe if necessary, is 
at the later of: (1) Within 1,500 flight cycles or 48 months from the 
replacement of the nacelle strut inboard and outboard midspar fittings, 
whichever occurs first, or (2) within 120 days.
    For the HFEC inspection, the repetitive interval is within 250 
flight cycles or 12 months, whichever occurs first.
    For the general visual inspection, the repetitive interval is 30 
flight cycles, except after both midspar fittings are replaced on the 
strut, the next inspection would be performed within 1,500 flight 
cycles or 48 months, whichever occurs first, from the replacement of 
both the nacelle strut inboard and outboard midspar fittings.
    Boeing 707 Alert Service Bulletin A3537, dated January 30, 2012, 
refers to Boeing 707/720 Service Bulletin 3183, Revision 5, dated 
September 16, 1993, as an additional source of guidance for the HFEC 
inspections of the midspar fittings of the engine number 2 and 3 
nacelle struts for cracks.

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 actions specified 
in the service information described previously, except as discussed 
under ``Differences Between the Proposed AD and the Service 
Information.''

Differences Between the Proposed AD and the Service Information

    Boeing 707 Alert Service Bulletin A3537, dated January 30, 2012, 
specifies to contact the manufacturer for instructions on how to repair 
certain conditions, but this proposed AD would require repairing those 
conditions 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.

[[Page 31764]]

    Boeing 707 Alert Service Bulletin A3537, dated January 30, 2012, 
refers to ``Manual 707, 720 NDT Part 6, 51-00-00 Figure 24 as an 
accepted procedure'' for the HFEC inspection. This proposed AD would 
require that the inspection must be done in accordance with Subject 51-
00-00 Figure 24, Steel Part Surface Inspection (Impedance Plane 
Display), of Part 6, Eddy Current, of the Boeing 707, 720 
Nondestructive Test Manual, Document D6-48023, Revision 120, dated 
March 15, 2012.

Costs of Compliance

    We estimate that this proposed AD affects 11 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
----------------------------------------------------------------------------------------------------------------
Detailed inspection, repetitive HFEC  23 work-hours x $85 per              $0           $1,955          $21,505
 inspections and repetitive general    hour = $1,955
 visual inspections of the midspar
 fittings of the nacelle strut.
----------------------------------------------------------------------------------------------------------------

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

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
              Action                    Labor cost                     Parts cost                    product
----------------------------------------------------------------------------------------------------------------
Install the correct part number    130 work-hours x $85  $7,867 x 4 = $31,468..................         $42,518
                                    per hour = $11,050
----------------------------------------------------------------------------------------------------------------

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

    1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2012-0490; Directorate Identifier 
2012-NM-066-AD.

(a) Comments Due Date

    We must receive comments by July 16, 2012.

(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

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 54, Nacelles/Pylons.

(e) Unsafe Condition

    This AD was prompted by reports of cracking of the midspar 
fittings and of the engine and nacelle strut separating from the 
airplane. We are issuing this AD to detect and correct cracking of 
the midspar fitting, which could result in separation of the nacelle 
strut and engine from the airplane while in flight, and consequent 
loss of controllability of the airplane.

(f) Compliance

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

(g) Detailed Inspection

    Within 120 days after the effective date of this AD: Do a 
detailed inspection of the midspar fittings of the engine number 2 
and 3 nacelle struts to confirm that the correct part number is 
installed, in accordance with the Accomplishment Instructions of 
Boeing 707 Alert Service Bulletin A3537, dated January 30, 2012. If 
any incorrect part number is found: Before further flight, install 
the correct part number, in accordance with the Accomplishment 
Instructions of Boeing

[[Page 31765]]

707 Alert Service Bulletin A3537, dated January 30, 2012.

    Note 1 to paragraph (g) of this AD:  Boeing 707 Alert Service 
Bulletin A3537, dated January 30, 2012, refers to Boeing 707/720 
Service Bulletin 3183, Revision 5, dated September 16, 1993, as an 
additional source of guidance for high frequency eddy current 
inspections of the midspar fittings of the engine number 2 and 3 
nacelle struts for cracks.

(h) High Frequency Eddy Current Inspection (HFEC)

    At the applicable times specified in paragraph 1.E., 
``Compliance,'' of Boeing 707 Alert Service Bulletin A3537, dated 
January 30, 2012, except as provided in paragraph (j) of this AD: Do 
an HFEC inspection of the midspar fittings of the engine number 2 
and 3 nacelle struts for cracks, in accordance with the 
Accomplishment Instructions of Boeing 707 Alert Service Bulletin 
A3537, dated January 30, 2012, except as provided by paragraph (k) 
of this AD. If any crack is found, before further flight, repair 
using a method approved in accordance with the procedures specified 
in paragraph (m) of this AD. Thereafter, repeat the inspection at 
the applicable intervals specified in paragraph 1.E., 
``Compliance,'' of Boeing 707 Alert Service Bulletin A3537, dated 
January 30, 2012.

(i) General Visual Inspection of the Nacelle Struts of Engine Numbers 
1, 2, 3, and 4

    At the applicable times in paragraph 1.E., ``Compliance,'' of 
Boeing 707 Alert Service Bulletin A3537, dated January 30, 2012, 
except as provided in paragraph (j) of this AD: Do a general visual 
inspection 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, in accordance with the Accomplishment Instructions of 
Boeing 707 Alert Service Bulletin A3537, dated January 30, 2012. 
Thereafter, repeat the inspection at the applicable intervals 
specified in paragraph 1.E., ``Compliance,'' of Boeing 707 Alert 
Service Bulletin A3537, dated January 30, 2012.
    (1) If any nacelle strut has drooped below its normal position: 
Before further flight, repair using a method approved in accordance 
with the procedures specified in paragraph (m) of this AD.
    (2) If any nacelle strut has not drooped below its normal 
position, and no droop stripe has been applied, as specified in 
Boeing 707/720 Service Bulletin 3377, dated November 21, 1979: At 
the applicable times in paragraph 1.E., ``Compliance,'' of Boeing 
707 Alert Service Bulletin A3537, dated January 30, 2012, except as 
provided in paragraph (j) of this AD: Apply the droop stripe to the 
nacelle strut and sailboat fairing, on each side of the engine 
numbers 1, 2, 3, and 4 nacelle struts, in accordance with the 
Accomplishment Instructions of Boeing 707 Alert Service Bulletin 
A3537, dated January 30, 2012.

(j) Exception to the Compliance Time

    Where Boeing 707 Alert Service Bulletin A3537, dated January 30, 
2012, specifies a compliance time based on ``the original issue date 
of this service bulletin,'' this AD requires compliance within the 
specified compliance time after the effective date of this AD.

(k) Exception to the Service Information

    Where Boeing 707 Alert Service Bulletin A3537, dated January 30, 
2012, refers to ``Manual 707, 720 NDT Part 6, 51-00-00 Figure 24 as 
an accepted procedure'' for the HFEC inspection, this AD requires 
that the inspection must be done in accordance with Subject 51-00-00 
Figure 24, Steel Part Surface Inspection (Impedance Plane Display), 
of Part 6, Eddy Current, of the Boeing 707, 720 Nondestructive Test 
Manual, Document D6-48023, Revision 120, dated March 15, 2012.

(l) Credit for Previous Actions

    This paragraph provides credit for the installation of the 
engine droop lines required by paragraph (i) of this AD, if those 
actions were performed before the effective date of this AD using 
Boeing 707/720 Service Bulletin 3377, dated November 21, 1979.

(m) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle Aircraft Certification Office (ACO), 
ANM-120S, 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 the Related Information 
section of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-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, Seattle ACO, ANM-120S 
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.

(n) Related Information

    (1) For more information about this AD, contact Berhane Alazar, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; 
phone: (425) 917-6577; fax: (425) 917-6590; email: 
Berhane.Alazar@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, Washington 98124-2207; telephone 
206-544-5000, extension 1; fax 206-766-5680; email 
me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You 
may review copies of the referenced service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, 
Washington. For information on the availability of this material at 
the FAA, call 425-227-1221.

    Issued in Renton, Washington, on May 21, 2012.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-13039 Filed 5-29-12; 8:45 am]
BILLING CODE 4910-13-P
```