[Federal Register Volume 72, Number 130 (Monday, July 9, 2007)]
[Proposed Rules]
[Pages 37130-37132]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-13263]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28620; Directorate Identifier 2007-NM-090-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP 
Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 
747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. This 
proposed AD would require repetitive inspections for cracking of the 
station (STA) 1241 bulkhead fittings just above the canted pressure 
deck; a one-time determination of the edge margin at seven fastener 
positions on each side of the airplane; and related investigative/
corrective actions if necessary. This proposed AD results from a report 
that an operator found a 1.65-inch crack on the STA 1241 bulkhead 
fitting on the left side of a Boeing Model 747-200F series airplane 
that had accumulated 17,332 total flight cycles. We are proposing this 
AD to detect and correct cracking in the STA 1241 bulkhead fittings, 
which could result in reduced structural integrity of the airplane.

DATES: We must receive comments on this proposed AD by August 23, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     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.
     Fax: (202) 493-2251.
     Hand Delivery: Room W12-140 on the ground floor of the 
West Building, 1200 New Jersey Avenue SE., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind 
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6437; 
fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
28620; Directorate Identifier 2007-NM-090-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Operations 
office between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Operations office (telephone (800) 647-

[[Page 37131]]

5527) is located on the ground floor of the West Building at the street 
address stated in the ADDRESSES section.

Discussion

    We have received a report that an operator found a 1.65-inch crack 
on the station (STA) 1241 bulkhead fitting on the left side of a Boeing 
Model 747-200F series airplane that had accumulated 17,332 total flight 
cycles. The crack was at a fastener hole just above the canted pressure 
deck. The STA 1241 fitting was replaced on this airplane. The STA 1241 
bulkhead fittings on Model 747 airplanes are 140-inch long aluminum 
forgings that extend from stringer 19 down through the pressure deck 
and attach to the wing rear spar. Cracking in the STA 1241 bulkhead 
fittings, if not found and repaired, can become large and result in 
reduced structural integrity of the airplane.

Other Relevant Rulemaking

    On January 16, 1990, we issued AD 90-06-06, amendment 39-6490, (55 
FR 8374, March 7, 1990), for certain Boeing Model 747 series airplanes 
listed in Boeing Document No. D6-35999, dated March 31, 1989. That AD 
requires, among other actions, replacement of the STA 1241 bulkhead 
splice straps in accordance with Boeing Service Bulletin 747-53-2283, 
Revision 3, dated November 1, 1989. We issued that AD to prevent 
structural failure of the affected airplanes. The date of that 
replacement is used to determine the compliance threshold for certain 
airplanes affected by this proposed AD.
    On March 18, 1992, we issued AD 92-08-02, amendment 39-8213 (57 FR 
12869, April 14, 1992), for certain Boeing Model 747 airplanes. That AD 
requires repetitive inspections of the STA 1241 bulkhead splice straps 
in accordance with Boeing Service Bulletin 747-53-2283, Revision 3, 
dated November 1, 1989, and repair if necessary. Boeing Service 
Bulletin 747-53-2219 is an alternative method of compliance (AMOC) for 
certain repairs required by that AD. The date of modification in 
accordance with Boeing Service Bulletin 747-53-2219 is used to 
determine the compliance threshold for certain airplanes affected by 
this proposed AD.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-53A2658, dated 
February 22, 2007. The service bulletin describes procedures for doing 
repetitive inspections (internal surface high frequency eddy current 
and external ultrasonic) for cracking of the STA 1241 bulkhead fittings 
just above the canted pressure deck. The service bulletin also 
specifies a one-time determination of the edge margin at seven fastener 
positions on each side of the airplane. If the edge margin of a 
fastener hole is less than 1.35 times the diameter of the hole, the 
related investigative/corrective action is contacting Boeing for 
special inspection data. For any crack found during a repetitive 
inspection, the corrective action is contacting Boeing for repair data.
    The compliance threshold for doing the initial inspection varies 
according to the configuration of the airplane, and according to the 
date of previous splice strap replacement or date of previous bulkhead 
modification as described above under ``Other Relevant Rulemaking.'' 
The thresholds described in Boeing Alert Service Bulletin 747-53A2658 
are as follows:
     For airplanes in the original configuration, or as 
modified in accordance with Boeing Service Bulletin 747-53-2219 (AMOC 
for AD 92-08-02): Before the accumulation of 10,000 total flight 
cycles, or 1,500 flight cycles after the effective date on Boeing Alert 
Service Bulletin 747-53A2658, whichever occurs later.
     For airplanes modified in accordance with Boeing Service 
Bulletin 747-53-2283 (AD 90-06-06): Before the accumulation of 5,000 
flight cycles since modification in accordance with Boeing Service 
Bulletin 747-53-2283, or within 1,500 flight cycles after the date on 
Boeing Alert Service Bulletin 747-53A2658, whichever occurs later.
    The compliance time for doing the first repeat inspection varies 
according to the smallest calculated edge margin at the seven fastener 
positions on each side of the airplane. The earliest specified range 
for doing the first repetitive inspection is before the accumulation of 
11,500 total flight cycles, or within 1,500 flight cycles since the 
initial inspection, whichever occurs later. The latest specified range 
for doing the first repeat inspection is before the accumulation of 
15,000 total flight cycles, or within 5,000 flight cycles since the 
initial inspection, whichever occurs later. Afterward, the repetitive 
intervals range from intervals not to exceed 1,500 flight cycles, to 
intervals not to exceed 5,000 flight cycles.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously, except as discussed under 
``Difference Between the Proposed AD and the Service Bulletin.''

Difference Between the Proposed AD and the Service Bulletin

    The service bulletin specifies to contact the manufacturer for 
instructions on how to do certain inspections and repairs, but this 
proposed AD would require inspection or repair in one of the following 
ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the Boeing Commercial Airplanes Delegation Option Authorization 
Organization whom we have authorized to make those findings.

Costs of Compliance

    There are about 455 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 133 airplanes of 
U.S. registry. The proposed actions would take about 14 work hours per 
airplane, at an average labor rate of $80 per work hour. Based on these 
figures, the estimated cost of the proposed AD for U.S. operators is 
$148,960, or $1,120 per airplane, per inspection cycle.

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.

[[Page 37132]]

Regulatory Findings

    We have 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 that the 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); and
    3. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, 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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

     Boeing: Docket No. FAA-2007-28620; Directorate Identifier 2007-
NM-090-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by August 
23, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B 
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series 
airplanes, certificated in any category; as identified in Boeing 
Alert Service Bulletin 747-53A2658, dated February 22, 2007.

Unsafe Condition

    (d) This AD results from a report that an operator found a 1.65-
inch crack on the station (STA) 1241 bulkhead fitting on the left 
side of a Boeing Model 747-200F series airplane that had accumulated 
17,332 total flight cycles. We are issuing this AD to detect and 
correct cracking in the STA 1241 bulkhead fittings, which could 
result in reduced structural integrity of the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Inspections and Corrective Action

    (f) At the applicable time specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 747-53A2658, dated 
February 22, 2007: Do internal surface high-frequency eddy current 
and external ultrasonic inspections for cracking of the STA 1241 
bulkhead fittings just above the canted pressure deck; determine the 
edge margin at seven fastener positions on each side of the 
airplane; and do all applicable related investigative/corrective 
actions; by doing all of the actions specified in the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2658, dated 
February 22, 2007, except as provided by paragraphs (f)(1) and 
(f)(2) of this AD. Do all applicable related investigative/
corrective actions before further flight. Repeat the inspections 
thereafter at the applicable interval specified in paragraph 1.E., 
``Compliance'' of the service bulletin.
    (1) Where the service bulletin specifies to contact Boeing for 
appropriate action, before further flight, do the action using a 
method approved in accordance with the procedures specified in 
paragraph (g) of this AD.
    (2) Where the service bulletin specifies a compliance time after 
the date on the service bulletin, this AD requires compliance within 
the specified compliance time after the effective date of this AD.

Alternative Methods of Compliance (AMOCs)

    (g)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.
    (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 an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle 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.

    Issued in Renton, Washington, on June 25, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-13263 Filed 7-6-07; 8:45 am]
BILLING CODE 4910-13-P