[Federal Register Volume 72, Number 80 (Thursday, April 26, 2007)]
[Proposed Rules]
[Pages 20782-20785]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-7978]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28015; Directorate Identifier 2006-NM-210-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR 
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 supersede an existing airworthiness 
directive (AD) that applies to all Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR 
series airplanes. The existing AD currently requires repetitive 
inspections for cracking of the station 800 frame assembly, and repair 
if necessary. This proposed AD would revise certain applicabilities and 
compliance times in the existing AD. This proposed AD results from 
several reports of cracks of the station 800 frame assembly on 
airplanes that had accumulated fewer total flight cycles than the 
initial inspection threshold in the original AD. We are proposing this 
AD to detect and correct fatigue cracks that could extend and fully 
sever the frame, which could result in development of skin cracks that 
could lead to rapid depressurization of the airplane.

DATES: We must receive comments on this proposed AD by June 11, 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: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., 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 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 ``Docket No. 
FAA-2007-28015; Directorate Identifier 2006-NM-210-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 the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or may 
can visit http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m. Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    On May 31, 2006, we issued AD 2006-12-12, amendment 39-14638 (71 FR 
33595, June 12, 2006), for all Boeing Model 747-100, 747-100B, 747-100B 
SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series 
airplanes. That AD requires repetitive inspections for cracking of the 
station 800 frame assembly, and repair if necessary. That AD resulted 
from several reports of cracks of the station 800 frame assembly on 
airplanes that had accumulated fewer total flight cycles than the 
initial inspection threshold in an existing AD that AD 2006-12-12 
superseded. We issued AD 2006-12-12 to detect and correct fatigue 
cracks that could extend and fully sever the frame, which could result 
in development of skin cracks that could

[[Page 20783]]

lead to rapid depressurization of the airplane.

Actions Since Existing AD Was Issued

    Since we issued AD 2006-12-12, errors have been found in the 
applicability of paragraphs (f) and (g), and the compliance times in 
Tables 1 and 2 of that AD. Therefore, we have made the following 
changes:
     We have removed the Model 747-200F from paragraphs (f) and 
(g) of this NPRM. The Model 747-200F was not included in the 
applicability of AD 2006-12-12 because the Model 747-200F is not 
subject to the unsafe condition.
     We have added the Model 747SR to paragraphs (f) and (g) of 
this NPRM and added a new Table 2 to accommodate it. These airplanes 
were identified in the main applicability in paragraph (c) of AD 2006-
12-12.
     We have removed the Model 747-100B SUD from paragraphs (f) 
and (g) of this NPRM because they are not subject to the requirements 
of AD 2001-14-22 (the AD that was superseded by AD 2006-12-12).
     We have revised the thresholds in paragraphs (f)(2), 
(f)(3), (h)(2), and (h)(3) of this NPRM to correct an inadvertent error 
in the compliance times.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 2006-12-12 and would retain the requirements of the 
existing AD. This proposed AD would also revise certain applicabilities 
and compliance times in the existing AD.

Costs of Compliance

    There are about 900 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 156 airplanes of 
U.S. registry.
    The repetitive inspections would take between 12 and 14 work hours 
per airplane, depending on the airplane configuration. The average 
labor rate is $80 per work hour. Based on these figures, the estimated 
cost of the currently required actions is between $149,760 and 
$174,720, or between $960 and $1,120 per airplane, per inspection 
cycle.
    The repetitive inspections of the expanded area would take between 
18 and 20 work hours per airplane, at an average labor rate of $80 per 
work hour. Based on these figures, the estimated cost of the new 
actions specified in this proposed AD for U.S. operators is between 
$224,640 and $249,600, or between $1,440 and $1,600 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.

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 
removing amendment 39-14638 (71 FR 33595, June 12, 2006) and adding the 
following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-28015; Directorate Identifier 2006-NM-
210-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by June 11, 
2007.

Affected ADs

    (b) This AD supersedes AD 2006-12-12.

Applicability

    (c) This AD applies to all Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR 
series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD results from several reports of cracks of the 
station 800 frame assembly on airplanes that had accumulated fewer 
total flight cycles than the initial inspection threshold in the 
existing AD. We are issuing this AD to detect and correct fatigue 
cracks that could extend and fully sever the frame, which could 
result in development of skin cracks that could lead to rapid 
depressurization 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.

Requirements of AD 2006-12-12 With Revised Appicabilities and 
Thresholds

Repetitive Inspections

    (f) For Boeing Model 747-100, 747-100B, 747-200B, 747-200C, and 
747SR series airplanes, as identified in Boeing Alert Service 
Bulletin 747-53A2451, including Appendix A, dated October 5, 2000: 
Do detailed, surface high-frequency eddy current (HFEC), and open-
hole HFEC inspections, as applicable, for cracking of the station 
800 frame assembly (including the inner chord strap, angles, and 
exposed web) between stringers 14 and 18, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2451, including Appendix A, dated October 5, 2000; or Boeing 
Alert Service Bulletin 747-53A2451, Revision 1, dated November 10, 
2005; after the effective date of this AD, only Revision 1 of the 
service bulletin may be used. Except as provided by paragraph (g) of 
this AD, do the inspection at the applicable time specified in Table 
1 or Table 2 of this AD, as applicable, and repeat the inspections 
thereafter at intervals not to exceed 3,000

[[Page 20784]]

flight cycles until the initial inspections required by paragraph 
(h) of this AD are accomplished.

Table 1.--Compliance Times for Boeing Model 747-100, 747-100B, 747-200B,
                      and 747-200C Series Airplanes
------------------------------------------------------------------------
  Total flight cycles as of August 30,
2001 (the effective date of AD 2001-14-   Do the inspection in paragraph
   22, amendment 39-12333, which was       (f) of this AD at this time
      superseded by AD 2006-12-12)
------------------------------------------------------------------------
(1) Fewer than 19,000..................  Before the accumulation of
                                          19,000 total flight cycles, or
                                          within 1,500 flight cycles
                                          after August 30, 2001,
                                          whichever comes later.
(2) 19,000 or more, but 24,250 or fewer  Within 1,500 flight cycles or
                                          12 months after August 30,
                                          2001, whichever comes first.
(3) 24,251 or more.....................  Within 750 flight cycles or 12
                                          months after August 30, 2001,
                                          whichever comes first.
------------------------------------------------------------------------


   Table 2.--Compliance Times for Boeing Model 747SR Series Airplanes
------------------------------------------------------------------------
Total flight cycles as of the effective   Do the inspection in paragraph
            date of this AD                (f) of this AD at this time
------------------------------------------------------------------------
(4) Fewer than 19,000..................  Before the accumulation of
                                          19,000 total flight cycles, or
                                          within 1,500 flight cycles
                                          after the effective date of
                                          this AD, whichever comes
                                          later.
(5) 19,000 or more, but 24,250 or fewer  Within 1,500 flight cycles or
                                          12 months after the effective
                                          date of this AD, whichever
                                          comes first.
(6) 24,251 or more.....................  Within 750 flight cycles or 12
                                          months after the effective
                                          date of this AD, whichever
                                          comes first.
------------------------------------------------------------------------

Adjustments to Compliance Time: Cabin Differential Pressure

    (g) For Boeing Model 747-100, 747-100B, 747-200B, and 747-200C 
series airplanes, as identified in Boeing Alert Service Bulletin 
747-53A2451, including Appendix A, dated October 5, 2000, that were 
inspected before July 17, 2006 (the effective date of AD 2006-12-
12); and for Boeing Model 747SR airplanes, as identified in Boeing 
Alert Service Bulletin 747-53A2451, that were inspected before the 
effective date of this AD: Except as provided by paragraph (i) of 
this AD, for the purposes of calculating the compliance threshold 
and repetitive interval for the actions required by paragraph (f) of 
this AD, the number of flight cycles in which cabin differential 
pressure is at 2.0 pounds per square inch (psi) or less need not be 
counted when determining the number of flight cycles that have 
occurred on the airplane, provided that the flight cycles with 
momentary spikes in cabin differential pressure above 2.0 psi are 
included as full pressure cycles. For this provision to apply, all 
cabin pressure records must be maintained for each airplane: No 
fleet-averaging of cabin pressure is allowed.

Repetitive Inspections of Expanded Area at a New Reduced Threshold

    (h) For all airplanes, at the applicable time specified in Table 
3 of this AD, except as provided by paragraph (i) of this AD, do the 
following inspections of the station 800 frame assembly in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2451, Revision 1, dated November 10, 2005: A 
detailed inspection for cracking of the inner chord strap, angles, 
and exposed web adjacent to the inner chords on the station 800 
frame between stringer 14 and stringer 18; and surface HFEC and 
open-hole HFEC inspections for cracking of the inner chord strap and 
angles. Do the initial inspections at the applicable time specified 
in Table 3 of this AD, and repeat the inspections thereafter at 
intervals not to exceed 3,000 flight cycles. Accomplishing the 
initial inspections required by this paragraph terminates the 
inspection requirements of paragraph (f) of this AD.

                   Table 3.--Revised Compliance Times
------------------------------------------------------------------------
   Total flight cycles as of July 17,    Do the inspections in paragraph
                 2006--                   (h) of this AD at this time--
------------------------------------------------------------------------
(1) Fewer than 16,000..................  Before the accumulation of
                                          16,000 total flight cycles, or
                                          within 1,500 flight cycles
                                          after July 17, 2006, whichever
                                          comes later.
(2) 16,000 or more, but 21,250 or fewer  Within 1,500 flight cycles
                                          after July 17, 2006, or within
                                          1,000 flight cycles after the
                                          effective date of this AD,
                                          whichever comes later.
(3) 21,251 or more.....................  Within 750 flight cycles after
                                          the July 17, 2006 or within
                                          500 flight cycles after the
                                          effective date of this AD,
                                          whichever comes later.
------------------------------------------------------------------------

Adjustments to Compliance Time: Cabin Differential Pressure

    (i) For the purposes of calculating the compliance threshold and 
repetitive interval for actions required by paragraphs (f) and (h) 
of this AD, for Boeing Model 747-100, 747-100B, 747-200B, and 747-
200C series airplanes, on or after July 17, 2006; and for Boeing 
Model 747SR series airplanes, on or after the effective date of this 
AD: All flight cycles, including the number of flight cycles in 
which cabin differential pressure is at 2.0 psi or less, must be 
counted when determining the number of flight cycles that have 
occurred on the airplane. However, for airplanes on which the 
repetitive interval for the actions required by paragraph (f) of 
this AD have been calculated in accordance with paragraph (g) of 
this AD by excluding the number of flight cycles in which cabin 
differential pressure is at 2.0 pounds psi or less: Continue to 
adjust the repetitive inspection interval in accordance with 
paragraph (g) of this AD until the initial inspections required by 
paragraph (h) of this AD are accomplished. Thereafter, no adjustment 
to compliance times based on paragraph (g) of this AD is allowed.

Repair

    (j) If any cracking is detected during any inspection required 
by paragraph (f) or (h) of this AD, and the service bulletin 
specifies to contact Boeing for appropriate action: Before further 
flight, repair using a method approved in accordance with the 
procedures specified in paragraph (l) of this AD.

[[Page 20785]]

No Report Required

    (k) Although the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2451, including Appendix A, dated October 5, 
2000; and Boeing Alert Service Bulletin 747-53A2451, Revision 1, 
dated November 10, 2005; describe procedures for reporting certain 
information to the manufacturer, this AD does not require that 
report.

Alternative Methods of Compliance (AMOCs)

    (l)(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) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
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 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.
    (4) AMOCs approved previously in accordance with AD 2001-14-22, 
are approved as AMOCs for the corresponding provisions of paragraphs 
(f) and (j) of this AD.
    (5) AMOCS approved previously in accordance with AD 2006-12-12, 
are approved as alternative methods of compliance with this AD.

    Issued in Renton, Washington, on April 19, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-7978 Filed 4-25-07; 8:45 am]
BILLING CODE 4910-13-P