[Federal Register Volume 70, Number 96 (Thursday, May 19, 2005)]
[Rules and Regulations]
[Pages 28803-28806]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-9880]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19538; Directorate Identifier 2003-NM-99-AD; 
Amendment 39-14098; AD 2005-10-21]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 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 airplanes. That AD 
currently requires inspections to detect cracks in the front spar 
pressure bulkhead chord, and repair if necessary. This new AD requires 
repetitive high frequency eddy current (HFEC) inspections of the body 
station (BS) 1000 bulkhead chord for cracks, repetitive detailed 
inspections of the bathtub fittings, if installed, for cracks, and 
corrective action if necessary. Initiation of the new inspections ends 
the inspections of the existing AD. This AD also revises the 
applicability of the existing AD to include additional airplanes. This 
AD is

[[Page 28804]]

prompted by reports of cracks in the BS 1000 bulkhead chord. We are 
issuing this AD to detect and correct fatigue cracks in the BS 1000 
bulkhead chord, which, if not repaired before they reach critical 
length, could result in the failure of the adjacent structure and skin 
and lead to in-flight depressurization of the airplane.

DATES: This AD becomes effective June 23, 2005.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-53A2471, dated March 27, 2003; and Boeing Service Bulletin 747-53-
2064, Revision 4, including Addendum, dated September 23, 1983; as 
listed in the regulations; is approved by the Director of the Federal 
Register as of June 23, 2005.

ADDRESSES: For service information identified in this AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207. You can examine this information 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/code_of_federal_regulations/ibr_locations.html.
    Docket: The AD docket contains the proposed AD, comments, and any 
final disposition. You can 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 U.S. 
Department of Transportation, 400 Seventh Street SW., room PL-401, 
Washington, DC. This docket number is FAA-2004-19538; the directorate 
identifier for this docket is 2003-NM-99-AD.

FOR FURTHER INFORMATION CONTACT: Nick Kusz, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6432; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend part 39 of the 
Federal Aviation Regulations (14 CFR part 39) with an AD to supersede 
AD 90-09-09, amendment 39-6586 (55 FR 17928, April 30, 1990), for 
certain Boeing Model 747 airplanes (a correction of that AD was 
published in the Federal Register on May 21, 1990 (55 FR 20894)). That 
action, published in the Federal Register on November 5, 2004 (69 FR 
64517), proposed to require inspections to detect cracks in the front 
spar pressure bulkhead chord, and repair if necessary (the actions 
previously required by AD 90-09-09). That action also proposed to 
require repetitive high frequency eddy current inspections of the body 
station 1000 bulkhead chord for cracks, repetitive detailed inspections 
of the bathtub fittings, if installed, for cracks, and corrective 
action, 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 
submitted on the proposed AD.

Request To Clarify Paragraph (h); Meaning of ``All'' Actions

    One commenter states that, as the proposed rule is currently 
written, operators would be required to replace all bathtub fittings if 
cracks are found at just one fitting. The operator points out that the 
referenced service bulletin states that operators replace only the 
items that are found to be cracked. However, the commenter points out 
that paragraph (h) of the proposed rule specifies that the corrective 
action must be taken by accomplishing ``all'' the actions specified in 
the accomplishment instructions of the service bulletin. The commenter 
states that a literal review and interpretation of paragraph (h) and 
the service bulletin could lead operators to the conclusion that all 
four bathtub fittings must be replaced if only one is found to be 
cracked.
    We agree. The intent of the proposed rule was not to require 
operators to replace all fittings in the event that only one is found 
cracked. However, it is important to note that the 6,000-cycle post-
modification inspection threshold is valid only if the chord is 
replaced along with all bathtub fittings that correspond to the side of 
the airplane (left or right) in which the chord was replaced. We have 
added a note to paragraph (h) of this final rule and revised (k) of the 
final rule to reflect this change. We have re-numbered the notes in the 
final rule accordingly.

Request To Remove Replacement Requirement

    One commenter requests that we remove the requirement to replace 
the bathtub fittings in order to be eligible for the 6,000-cycle post-
modification threshold after the chord replacement. The commenter gives 
several reasons for this request: There have been no reports of cracked 
bathtub fittings; the replacement bathtub fittings are the same 
material, in some cases, as the original fittings; and bathtub fittings 
must be removed for chord replacement, thereby allowing thorough 
inspections of the fittings.
    We disagree. Although the commenter states otherwise, we have 
received reports of cracked bathtub fittings. In addition, the fact 
that the replacement fittings are of the same material as the original 
fittings does not mean that the fittings should not be replaced. 
Moreover, replacing all fittings, not just the damaged ones, is 
necessary in order to apply the 6,000-cycle post-modification 
threshold. Operators still have the option to replace only those 
bathtub fittings with detected cracking, and to continue with the 
3,000-cycle inspection interval. No change to the final rule is 
necessary in this regard.

Request To Revise Cost Estimate

    One commenter, an airplane operator having no technical objections, 
requests that the cost estimate be recalculated to include the work 
hours necessary for access and restoration. The commenter states that 
access and restoration can require up to 24 work hours for each 
airplane, and that such tasks do not occur frequently enough to warrant 
leaving them out of the cost estimate.
    We disagree. In establishing the requirements of all ADs, we 
typically do not include incidental costs such as the time required to 
gain access and close up, planning time, or the time needed for other 
administrative actions. Because incidental costs may vary significantly 
from operator to operator, they are almost impossible to calculate. The 
work hours that are needed to accomplish the actions required by this 
AD represent the time necessary to perform only the actions actually 
required by this AD (that is, the inspection). No change to the final 
rule is necessary in this regard.

Explanation of Changes Made to the Proposed AD

    We have revised the subject heading to identify model designations 
as published in the most recent type certificate data sheet for the 
affected models.
    Boeing has received a Delegation Option Authorization (DOA). We 
have revised paragraph (l) of the final rule to delegate the authority 
to approve an alternative method of compliance for any repair required 
by this AD to the Authorized Representative for the Boeing DOA 
Organization.
    We have also revised paragraph (i) of the final rule to allow any 
crack in the subject area to be repaired according to data that conform 
to the airplane's type

[[Page 28805]]

certificate and that are approved by an Authorized Representative for 
the Boeing DOA Organization whom we have authorized to make such 
findings.

Conclusion

    We have carefully reviewed the available data, including the 
comments that have been submitted, 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 1,350 Model 747 series airplanes worldwide of the 
affected design. This AD affects about 245 airplanes of U.S. registry.
    The actions that are required by AD 90-09-09 and retained in this 
AD take about 84 work hours per airplane, at an average labor rate of 
$65 per work hour. We estimate 102 airplanes of U.S. registry are 
affected by AD 90-09-09. Based on these figures, the estimated cost of 
the currently required actions is $556,920, or $5,460 per airplane, per 
inspection cycle.
    The new inspections take about 14 work hours per airplane, at an 
average labor rate of $65 per work hour. Based on these figures, the 
estimated cost of the new actions specified in this AD for U.S. 
operators is $222,950, or $910 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. 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 FAA amends Sec.  39.13 by removing amendment 39-6586 (55 FR 
17928, April 30, 1990), corrected at 55 FR 20894, May 21, 1990, and by 
adding the following new airworthiness directive (AD):

2005-10-21 Boeing: Amendment 39-14098. Docket No. FAA-2004-19538; 
Directorate Identifier 2003-NM-99-AD.

Effective Date

    (a) This AD becomes effective June 23, 2005.

Affected ADs

    (b) This AD supersedes AD 90-09-09, amendment 39-6586 (55 FR 
20894, May 21, 1990).

Applicability

    (c) This AD applies to Boeing Model 747 series airplanes, line 
numbers 1 through 1307 inclusive, 1309 through 1312 inclusive, and 
1314; certificated in any category.

Unsafe Condition

    (d) This AD was prompted by reports of cracks in the body 
station (BS) 1000 bulkhead chord. We are issuing this AD to detect 
and correct fatigue cracks in the BS 1000 bulkhead chord, which, if 
not repaired before they reach critical length, could result in the 
failure of the adjacent structure and skin and lead to in-flight 
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.

Restatement of Requirements of AD 90-09-09

    (f) For airplanes listed in Boeing Service Bulletin 747-53-2064, 
Revision 4, dated September 23, 1983, that have not been modified in 
accordance with Boeing Service Bulletin 747-53-2064, dated July 25, 
1972: Within the next 1,000 landings after October 15, 1984 (the 
effective date of AD 84-18-06, amendment 39-4912), or prior to the 
accumulation of 10,000 landings, whichever occurs later, and 
thereafter at intervals not to exceed 7,000 landings, conduct a high 
frequency eddy current (HFEC) inspection of the chord to detect 
cracks between stringers S-37 and S-39 at the chord radius, heel, 
and flanges adjacent to the fastener holes identified for inspection 
in Boeing Service Bulletin 747-53-2064, Revision 4, dated September 
23, 1983. If cracks are found in the pressure bulkhead chord, 
accomplish the repair in accordance with the service bulletin before 
further flight. Repair of cracks along the chord radius under 5 
inches in length, or across a chord flange that have not severed the 
chord flange, may be deferred 1,000 landings by stop drilling and 
reinspecting for crack progression every 200 landings using HFEC. If 
crack progression is found, repair in accordance with the service 
bulletin prior to further flight. Inspections are to continue at 
intervals not to exceed 7,000 landings after repair.
    (g) For airplanes listed in Boeing Service Bulletin 747-53-2064, 
Revision 4, dated September 23, 1983, that have been modified in 
accordance with Boeing Service Bulletin 747-53-2064, dated July 25, 
1972: Within the next 1,000 landings after October 15, 1984, or 
prior to the accumulation of 10,000 landings after the modification, 
whichever is later, and thereafter at intervals not to exceed 10,000 
landings, conduct an HFEC inspection to detect cracks in the front 
spar pressure bulkhead lower chord heel from stringers S-37 to S-39, 
and conduct an ultrasonic inspection to detect cracks in the 
fuselage skin originating at the indicated fastener holes beneath 
the forward drag splice fitting flanges, in accordance with the 
service bulletin. If any cracks are found, repair in accordance with 
Boeing Service Bulletin 747-53-2064, Revision 4, dated September 23, 
1983, before further flight. Inspections are to continue at 
intervals not to exceed 10,000 landings after repair.

New Requirements of This AD

Initial Inspections

    (h) At the later of the times specified in paragraph (h)(1), 
(h)(2), or (h)(3) of this AD: Except as provided by paragraph (i) of 
this

[[Page 28806]]

AD, perform an HFEC inspection of BS 1000 bulkhead chord for cracks, 
a detailed inspection of the bathtub fittings, if installed, for 
cracks, and corrective action, as applicable, by accomplishing all 
the actions specified in the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-53A2471, dated March 27, 2003. Any 
applicable corrective action must be done before further flight. 
Corrective actions include replacing only those bathtub fittings 
that are found to be cracked. Accomplishment of the HFEC and 
detailed inspections required by this paragraph ends the 
requirements of paragraphs (f) and (g) of this AD.
    Note 1: The 6,000-cycle post-modification inspection threshold 
in paragraph (k) of this AD is valid only if the chord is replaced 
along with all bathtub fittings corresponding to the side of the 
airplane (left or right) in which the chord was replaced.
    Note 2: For the purposes of this AD, a detailed inspection is 
``an intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirrors, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''
    (1) Prior to the accumulation of 10,000 total flight cycles.
    (2) Within 18 months after the effective date of this AD.
    (3) For airplanes on which the repair (i.e., chord replacement) 
has been accomplished in accordance with Boeing Service Bulletin 
747-53-2362, dated March 26, 1992, or in accordance with paragraph 
(f) or (g) of this AD (i.e., per Boeing Service Bulletin 747-53-
2064, Revision 4, dated September 23, 1983): Within 3,000 flight 
cycles after the replacement was accomplished.
    Note 3: Repairs (i.e., chord replacement) accomplished prior to 
the effective date of this AD in accordance with Boeing Service 
Bulletin 747-53-2064, Revision 1, dated May 18, 1973; Revision 2, 
dated February 22, 1974; Revision 3, dated September 13, 1974; 
Revision 5, dated July 23, 1987; or Revision 6, dated June 22, 1989; 
are also considered to be applicable to the inspection threshold 
specified in paragraph (h)(3) of this AD.
    (i) If any crack is found during any inspection required by 
paragraph (h) of this AD, and Boeing Alert Service Bulletin 747-
53A2471, dated March 27, 2003, specifies contacting Boeing for 
additional information: Before further flight, repair according to a 
method approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA; or according to data meeting the certification 
basis of the airplane approved by an Authorized Representative for 
the Boeing 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 reference this AD.

Repetitive Inspections

    (j) Except as provided by paragraph (k) of this AD, repeat the 
inspections required by paragraph (h) of this AD thereafter at 
intervals not to exceed 3,000 flight cycles.
    (k) For the side of the airplane on which the chord and all 
corresponding bathtub fittings for that side of the airplane (left 
or right) were replaced in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2471, dated 
March 27, 2003: Repeat the inspections required by paragraph (h) of 
this AD within 6,000 flight cycles after accomplishing replacement 
of the chord and bathtub fittings. Thereafter repeat the inspections 
at intervals not to exceed 3,000 flight cycles.

Alternative Methods of Compliance (AMOC)

    (l)(1) In accordance with 14 CFR 39.19, the Manager, Seattle 
ACO, FAA, is authorized to approve AMOCs for this AD.
    (2) AMOCs, approved previously in accordance with AD 90-09-09, 
amendment 39-6586, are approved as AMOCs to paragraph (f) or (g) of 
this AD, as applicable.
    (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 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 approval must specifically refer to this AD.

Material Incorporated by Reference

    (m) You must use Boeing Alert Service Bulletin 747-53A2471, 
dated March 27, 2003; and Boeing Service Bulletin 747-53-2064, 
Revision 4, including Addendum, dated September 23, 1983; as 
applicable, to perform the actions that are required by this AD, 
unless the AD specifies otherwise. The Director of the Federal 
Register approves the incorporation by reference of this document in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. For copies of the 
service information, contact Boeing Commercial Airplanes, P.O. Box 
3707, Seattle, Washington 98124-2207.
    You may view the AD docket at the Docket Management Facility, 
U.S. Department of Transportation, 400 Seventh Street SW, room PL-
401, Nassif Building, Washington, DC. To review copies of the 
service information, go 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 11, 2005.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-9880 Filed 5-18-05; 8:45 am]
BILLING CODE 4910-13-P