[Federal Register Volume 71, Number 112 (Monday, June 12, 2006)]
[Rules and Regulations]
[Pages 33595-33598]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-5207]



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  Federal Register / Vol. 71, No. 112 / Monday, June 12, 2006 / Rules 
and Regulations  

[[Page 33595]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24102; Directorate Identifier 2005-NM-244-AD; 
Amendment 39-14638; AD 2006-12-12]
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: Final rule.

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

SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD), which applies to certain Boeing Model 747-100 and -200 series 
airplanes. That AD currently requires repetitive inspections for 
cracking of the station 800 frame assembly, and repair if necessary. 
This new AD retains the repetitive inspection requirements of the 
existing AD, but expands the area to be inspected. This AD also reduces 
the initial inspection threshold, removes the adjustment of the 
compliance threshold and repetitive interval based on cabin 
differential pressure, and adds airplanes to the applicability. 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.

DATES: This AD becomes effective July 17, 2006.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of July 17, 
2006.
    On August 30, 2001 (66 FR 38891, July 26, 2001), the Director of 
the Federal Register approved the incorporation by reference of Boeing 
Alert Service Bulletin 747-53A2451, including Appendix A, dated October 
5, 2000.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
Room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6437; 
fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

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 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 street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that supersedes AD 2001-14-22, amendment 
39-12333 (66 FR 38891, July 26, 2001). The existing AD applies to 
certain Boeing Model 747-100 and -200 series airplanes. That NPRM was 
published in the Federal Register on March 8, 2006 (71 FR 11551). That 
NPRM proposed to require repetitive inspections for cracking of the 
station 800 frame assembly, and repair if necessary.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments that have been 
received on the NPRM.

Support for the Proposed AD

    Air Transport Association (ATA), on behalf of its member Northwest 
Airlines, concurs with the intent of the NPRM.

Requests To Remove or Revise 12-Month Grace Period From Table 2

    Boeing requests that we remove the 12-month compliance time from 
paragraph (h), Table 2, items (2) and (3), of the NPRM. Boeing states 
that the cracking that is the subject of the NPRM is initiated and 
propagated solely by cyclic loading as measured in flight cycles. 
Boeing also states that calendar time has no bearing on the initiation 
rate of the cracking. ATA, on behalf of Northwest Airlines, also 
comments on the 12-month grace period. Northwest states that, for 
operators who have planned completion of the initial inspection near 
the previously defined 19,000 flight-cycle threshold in accordance with 
AD 2001-14-22, the proposed 12-month grace period could result in 
unscheduled out-of-service airplanes. Northwest adds that the cracking 
addressed by the NPRM is attributed to fatigue, which is driven by 
flight cycles rather than calendar days. Northwest therefore requests 
that we change the calendar time from 12 months to 18 months, which is 
consistent with the Boeing maintenance interval on Model 747 airplanes. 
Northwest suggests limiting this calendar-time change to airplanes that 
have not exceeded the previously mandated 19,000 total-flight-cycle 
threshold. ATA states that this change would avoid disruption of 
maintenance visits that were scheduled to facilitate compliance with 
the existing AD.
    We agree that a grace period based on calendar time is 
inappropriate because, as Boeing states and ATA notes, the cracking 
that is the subject of the NPRM is initiated and propagated solely by 
cyclic loading as measured in flight cycles. For this reason, we 
disagree with ATA's request to extend the grace period to 18 months for 
certain airplanes. Instead, we have revised Table 2 of the final rule 
to remove the 12-month portion of the grace period, and to include only 
the compliance time based on flight cycles. This change will ensure an 
equivalent level of safety and

[[Page 33596]]

alleviate concerns about unscheduled out-of-service airplanes.

Request To Clarify Expanded Inspection Requirements for Previously 
Inspected Airplanes

    ATA, on behalf of Northwest Airlines, also requests that, for 
airplanes on which the inspections in accordance with AD 2001-14-22 
have been done, we clarify that the inspection per procedures defined 
in Boeing Alert Service Bulletin 747-53A2451, Revision 1, dated 
November 10, 2005, be accomplished at the next scheduled repeat 
inspection. Northwest states that this request complies with the 
statement in the service bulletin that specifies no additional work is 
necessary on airplanes previously inspected in accordance with the 
initial release of the service bulletin (dated October 5, 2000), and to 
do the expanded inspection at the time of the next scheduled 
inspection.
    We partially agree. We agree with the commenter that, for the 
previously accomplished inspections, compliance with AD 2001-14-22 was 
met if the inspection was accomplished in accordance with the original 
release of the service bulletin (Boeing Alert Service Bulletin 747-
53A2451, including Appendix A, dated October 5, 2000). It is the intent 
of the NPRM to match the service information provided by Boeing. We 
disagree that any change is necessary to clarify the AD. Paragraph (f) 
of the AD states that, prior to the effective date of this new AD, the 
inspections may be accomplished in accordance with either the initial 
release or Revision 1 of the service bulletin. After the effective date 
of this AD, only Revision 1 may be used. We have not changed the AD in 
this regard.

Explanation of Change to Costs of Compliance

    After the NPRM was issued, we reviewed the figures we have used 
over the past several years to calculate AD costs to operators. To 
account for various inflationary costs in the airline industry, we find 
it necessary to increase the labor rate used in these calculations from 
$65 per work hour to $80 per work hour. The cost impact information, 
below, reflects this increase in the specified hourly labor rate.

Conclusion

    We have carefully reviewed the available data, including the 
comments that have been received, and determined that air safety and 
the public interest require adopting the AD with the changes described 
previously. We have determined that these changes will neither increase 
the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 900 airplanes of the affected design in the 
worldwide fleet. This AD will affect about 156 airplanes of U.S. 
registry.
    The inspections that are specified in AD 2001-14-22, and retained 
in this AD, 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 $960 and $1,120 per airplane, per 
inspection cycle.
    The new actions will 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 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 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); 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 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-12333 (66 FR 38891, July 26, 2001) and by adding 
the following new airworthiness directive (AD):


2006-12-12 Boeing: Amendment 39-14638. Docket No. FAA-2006-24102; 
Directorate Identifier 2005-NM-244-AD.

Effective Date

    (a) This AD becomes effective July 17, 2006.

Affected ADs

    (b) This AD supersedes AD 2001-14-22.

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

[[Page 33597]]

the compliance times specified, unless the actions have already been 
done.

Restatement of the Requirements of AD 2001-14-22

Repetitive Inspections

    (f) For Boeing Model 747-100, 747-100B, 747-100B SUD, -200B, 
747-200C, and 747-200F 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 of this AD, and repeat the inspections 
thereafter at intervals not to exceed 3,000 flight cycles until the 
initial inspections required by paragraph (h) of this AD are 
accomplished.

                       Table 1.--Compliance Times
------------------------------------------------------------------------
  Total flight cycles as of
     August 30, 2001 (the        Do the inspection in paragraph (f) of
effective date of AD 2001-14-             this AD at this time
             22)
------------------------------------------------------------------------
(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        Within 1,500 flight cycles or 12 months
 21,250 or fewer.               after August 30, 2001, whichever comes
                                first.
(3) 21,251 or more...........  Within 750 flight cycles or 12 months
                                after August 30, 2001, whichever comes
                                first.
------------------------------------------------------------------------

Adjustments to Compliance Time: Cabin Differential Pressure

    (g) For Boeing Model 747-100, 747-100B, 747-100B SUD, -200B, 
747-200C, and 747-200F series airplanes, as identified in Boeing 
Alert Service Bulletin 747-53A2451, including Appendix A, dated 
October 5, 2000, that are 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.

New Requirements of this AD

Repetitive Inspections of Expanded Area at a New Reduced Threshold

    (h) For all airplanes, at the applicable time specified in Table 
2 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 2 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 2.--Revised Compliance Times
------------------------------------------------------------------------
Total flight cycles as of the    Do the inspections in paragraph (h) of
  effective date of this AD               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 the effective date of this
                                AD, whichever comes later.
(2) 16,000 or more, but        Within 1,500 flight cycles after the
 24,250 or fewer.               effective date of this AD.
(3) 24,251 or more...........  Within 750 flight cycles after the
                                effective date of this AD.
------------------------------------------------------------------------

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, 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.

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.

[[Page 33598]]

    (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.

Material Incorporated by Reference

    (m) You must use 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; as 
applicable; to perform the actions that are required by this AD, 
unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of Boeing Alert Service Bulletin 747-
53A2451, Revision 1, dated November 10, 2005, in accordance with 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) On August 30, 2001 (66 FR 38891, July 26, 2001), the 
Director of the Federal Register approved the incorporation by 
reference of Boeing Alert Service Bulletin 747-53A2451, including 
Appendix A, dated October 5, 2000.
    (3) Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for a copy of this service information. You 
may review copies at the Docket Management Facility, U.S. Department 
of Transportation, 400 Seventh Street, SW., Room PL-401, Nassif 
Building, Washington, DC; on the Internet at http://dms.dot.gov; or 
at the National Archives and Records Administration (NARA). For 
information on the availability of this material at the NARA, call 
(202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on May 31, 2006.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-5207 Filed 6-9-06; 8:45 am]
BILLING CODE 4910-13-P