AD 2002-18-04

[Federal Register Volume 67, Number 176 (Wednesday, September 11, 2002)]
[Rules and Regulations]
[Pages 57510-57514]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 02-22855]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-34-AD; Amendment 39-12878; AD 2002-18-04]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747-100, 747-100B, 747-100B SUD, 
747-200B, 747-300, 747SP, and 747SR series airplanes, that requires 
one-time inspections for cracking in certain upper deck floor beams and 
follow-on actions. The actions specified by this AD are intended to 
find and fix cracking in certain upper deck floor beams. Such cracking 
could extend and sever floor beams adjacent to the body frame and 
result in rapid depressurization of the airplane. This action is 
intended to address the identified unsafe condition.

DATES: Effective October 16, 2002.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 16, 2002.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., Suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1153; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-100, 747-
100B, 747-100B SUD, 747-200B, 747-200F, 747-300, 747SP, and 747SR 
series airplanes was published in the Federal Register on January 2, 
2002 (67 FR 38). That action proposed to require one-time inspections 
for cracking in certain upper deck floor beams and follow-on actions.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Supportive Comment

    One commenter agrees with the proposed rule.

Request To Withdraw Proposed Rule

    One commenter is concerned with the continuing trend to issue 
Airworthiness Directives (ADs) that overlap or are in close proximity 
to other ADs, based on isolated reports of minor structural cracks. The 
commenter provided the AD numbers for ADs that require inspections and 
repair of the same structure specified in this proposed rule. The 
commenter notes that the Boeing 747 Maintenance Program requires visual 
inspections of the upper deck floor beam of the fuselage frame 
interface, in addition to those inspections required by the previously 
issued ADs. The commenter adds that the few reports of upper chord 
cracking of the floor beam can be adequately detected by the 
maintenance program inspections before an unsafe condition could 
develop.

[[Page 57511]]

    Although the commenter does not make any specific request, the FAA 
infers that the commenter wants to withdraw the proposed rule. We 
acknowledge that Boeing Model 747 series airplanes have an extensive 
service life and that numerous inspections have been performed as part 
of the FAA-approved 747 maintenance program. (All operators are 
required to maintain their airplanes in accordance with an FAA-approved 
maintenance program as required for continued airworthiness.) However, 
we find that the subject inspections in the maintenance program do not 
adequately address certain in-service difficulties and thus do not 
adequately address the identified unsafe condition. Additionally, we do 
not agree that the cited ADs already require inspections and repair of 
the same structure specified in this final rule. Therefore, the FAA has 
determined that the proposed rule is appropriate and warranted.

Exclude Certain Flight Cycles

    One commenter states that the service bulletin referenced in the 
proposed rule specifies the exclusion of flight cycles with a cabin 
pressure differential of 2.0 pounds per square inch (psi) or less. The 
commenter asks that this exclusion be added to the final rule.
    We agree with the commenter in that this exclusion is specified in 
the referenced service bulletin. Paragraph (a) of this final rule has 
been changed to exclude flight cycles with a cabin pressure 
differential of 2.0 psi or less, as stated above.

Reduce Applicability

    One commenter asks that all references to Boeing Model 747-200F 
series airplanes be deleted from the proposed rule. The commenter 
states that the service bulletin referenced in the proposed rule adds 
the same inspection of the upper deck floor beams required by AD 98-09-
17 for Model 747-200F series airplanes.
    We agree with the commenter. AD 98-09-17, amendment 39-10498 (63 FR 
20311, April 24, 1998), is applicable to Boeing Model 747-200F and -
200C series airplanes. That AD requires repetitive inspections or a 
one-time inspection to detect cracking of certain areas of the upper 
deck floor beams; and corrective actions, if necessary. Therefore, we 
have deleted all references to Model 747-200F from this final rule.

Allow Permanent Repairs Specified in Service Information

    One commenter states that paragraph (c) of the proposed rule would 
require repair of any crack found during the proposed inspections 
either by a temporary repair, per the referenced service bulletin, or 
by accomplishing an approved permanent repair. The commenter adds that 
Note 3 of the proposed rule states that the referenced service bulletin 
does not contain instructions for permanent repairs; however, page 29 
of the service bulletin does contain permanent repair instructions. The 
commenter notes that paragraph (c)(2) of the proposed rule should be 
changed to allow permanent repairs to be done per the service bulletin.
    We agree with the commenter that the referenced service bulletin 
does contain permanent repair instructions for floor beam web, strap, 
and frame cracks, but not upper chord cracks. Therefore, paragraph 
(c)(2) of this final rule has been changed to specify repair according 
to the service bulletin, unless the service bulletin specifies 
contacting the manufacturer. Also, Note 3 has been removed from this 
final rule and subsequent notes have been renumbered accordingly.

Change Certain Wording

    One commenter asks that the wording specified in paragraphs 
(c)(1)(i), (c)(1)(ii), and (d) of the proposed rule be changed. The 
commenter states that the words ``temporary repair'' should be changed 
to ``time-limited repair.'' The commenter notes that, since a time-
limited repair must be replaced with a permanent repair within 18 
months or 1,500 flight cycles, this change would ensure that a 
permanent repair would be installed before the modification is done. 
The commenter adds that the word ``repair'' specified in paragraph (d) 
of the proposed rule should be changed to ``permanent repair.''
    We agree with the commenter. The term ``time-limited'' repair 
should be used instead of ``temporary'' repair, for clarity. We also 
agree that the post-modification inspection threshold should begin 
after installation of a permanent repair. Paragraphs (c)(1)(i), 
(c)(1)(ii), and (d) of this final rule have been changed accordingly.

Change Cost Impact

    One commenter asks that the Cost Impact section of the proposed 
rule be changed. The commenter states that it will take 8 work hours to 
accomplish the initial inspections, but an additional 22 work hours to 
gain access and close up in order to accomplish the inspections. The 
commenter adds that the 24 work hours necessary to accomplish the 
modification are in addition to the hours for the inspections, and for 
gaining access and close up.
    We do not agree to change the work hours for the initial 
inspections. The number of work hours necessary to accomplish the 
inspections, specified as 8 in the cost impact information, is 
consistent with the service bulletin. This number represents the time 
necessary to perform only the inspections actually required by this AD. 
The FAA recognizes that, in accomplishing the requirements of any AD, 
operators may incur ``incidental'' costs in addition to the ``direct'' 
costs. The cost analysis in AD rulemaking actions, however, typically 
does not include incidental costs, such as the time required to gain 
access and close up, planning time, or time necessitated by other 
administrative actions. Because incidental costs may vary significantly 
from operator to operator, they are almost impossible to calculate.
    We agree that adding the words ``in addition to the inspection'' to 
the 24 work hours for the modification will provide clarification. The 
cost impact section has been changed accordingly.

Change Paragraph (d) of the Proposed Rule

    One commenter asks that paragraph (d) of the proposed rule be 
changed. The commenter reiterates the requirements in paragraph (d) of 
the proposed rule and suggests alternatives to that paragraph as 
follows: 1. Issue the proposed rule only after the referenced service 
bulletin is revised to include post-modification/repair instructions; 
2. Specifically define the inspection requirements and include them in 
paragraph (d); or 3. Omit paragraph (d) from the proposed rule, and, if 
necessary, issue a revised or new AD after the service bulletin has 
been revised.
    We do not agree with the commenter. Alternative 1. would delay 
issuance of the proposed rule, which would not address the unsafe 
condition in a timely manner. At this time, we do not have the 
necessary data to incorporate alternative 2. When the manufacturer 
revises its service bulletin to include post-modification inspections, 
we can consider approving it as an alternative method of compliance 
(AMOC) to the final rule. Regarding alternative 3., we have determined 
that post-modification inspections should be addressed in this final 
rule; therefore, paragraph (d) of this final rule will not be omitted.

[[Page 57512]]

Reference Revised Service Information

    One commenter asks that the FAA reference the revised service 
bulletin that will be issued later, rather than the current issue 
referenced in the proposed rule. The commenter states that there are 
inconsistencies and minor errors in the referenced service bulletin.
    While we acknowledge the commenter's statements about the accuracy 
of certain wording in the accomplishment instructions of the service 
bulletin, we do not concur with the request to reference a service 
bulletin that has not yet been issued or reviewed and approved by us. 
The airplane manufacturer is aware of the discrepancies in the service 
bulletin instructions and may issue a revision of the service bulletin 
in the future. However, considering the criticality of the unsafe 
condition noted previously, we find it would be inappropriate to delay 
the issuance of this AD until a revised service bulletin is available. 
No change to the final rule is necessary in this regard.

Change Certain Sections in the Preamble

    One commenter asks that the sentence in the Summary section of the 
proposed rule be changed from ``This action is intended to address the 
identified unsafe condition,'' to ``This action is intended to address 
the identified potential unsafe condition.'' The commenter also asks 
that the sentence be changed in the Explanation of Requirements of 
Proposed Rule section. The commenter states that while a severed upper 
chord of the upper floor beam would pose an unsafe condition, a chord 
that has not cracked, but at some time may crack, poses a ``potential'' 
unsafe condition.
    We acknowledge but do not agree with the commenter's request. The 
sentence in the Summary section specifies that the action is intended 
to address the identified unsafe condition. The final rule is necessary 
to find and fix cracking in certain upper deck floor beams, which is 
not a ``potential'' unsafe condition. Additionally, the Explanation of 
Requirements of Proposed Rule section is not restated in this final 
rule. No change to the final rule is necessary in this regard.

Reduce Compliance Time

    One commenter asks that the compliance time specified in paragraph 
(a)(1) of the proposed rule be reduced. The commenter states that 
paragraph (a)(1) of the proposed rule specifies the inspection of 
airplanes with 22,000 flight cycles or less be accomplished within 
1,500 flight cycles after the effective date of the AD. The commenter 
notes that the inspection could occur as late as 23,500 flight cycles 
and adds that paragraph (a)(2) of the proposed rule requires that the 
inspections be accomplished on airplanes with more than 22,000 flight 
cycles within 500 flight cycles. The commenter suggests that paragraph 
(a)(1) of the proposed rule be changed to require the inspection of 
airplanes within 22,000 flight cycles or less to be accomplished within 
1,500 flight cycles after the effective date of the AD, but no later 
than 22,500 flight cycles.
    We do not agree with the commenter. The commenter provides no data 
to justify its statement that the proposed compliance time should be 
changed in the manner suggested. In developing an appropriate 
compliance time for this AD, we considered not only the manufacturer's 
recommendation, but the degree of urgency associated with addressing 
the subject unsafe condition, the average utilization of the affected 
fleet, and the time necessary to perform the inspections. We find that 
the compliance time required by paragraph (a)(1) of the final rule is 
an appropriate interval for affected airplanes to continue to operate 
without compromising safety. No change to the final rule is necessary 
in this regard.

Allow Operators To Change Method of Inspection

    One commenter (the airplane manufacturer) asks that, to avoid 
confusion, the instructions specified in paragraph (d) of the proposed 
rule should be changed to allow for operators to change the method of 
inspection. The commenter suggests that, instead of ``Repeat the 
inspection within * * *'' as specified in paragraphs (d)(1) and (d)(2) 
of the proposed rule, the wording be changed to ``Conduct the next 
inspection within * * *'' The commenter states that this wording seems 
to imply that the operator must continue with the same inspection 
method.
    We do not agree with the commenter that the wording specified in 
paragraph (d) of the final rule obligates the operator to continue 
using the same inspection method. However, if the commenter needs 
further clarification, the clarification can be made in a future 
revision to the service bulletin. The FAA may then consider approving 
the bulletin as an AMOC to the final rule. No change to the final rule 
is necessary in this regard.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 539 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 168 airplanes of U.S. registry 
will be affected by this AD.
    It will take approximately 8 work hours per airplane to accomplish 
the initial inspections, at the average labor rate of $60 per work 
hour. Based on these figures, the cost impact of these required 
inspections on U.S. operators is estimated to be $80,640, or $480 per 
airplane.
    It will take approximately 24 work hours per airplane to accomplish 
the modification or permanent repair, in addition to the inspection, at 
the average labor rate of $60 per work hour. Based on these figures, 
the cost impact of the required modification or repair on U.S. 
operators is estimated to be $241,920 or $1,440 per airplane.
    It will take approximately 8 work hours per airplane to accomplish 
the post-modification/repair inspections, at the average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
required post-modification/repair inspections on U.S. operators is 
estimated to be $80,640 or $480 per airplane, per inspection cycle.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the requirements of this 
AD action, and that no operator would accomplish those actions in the 
future if this AD were not adopted. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

Regulatory Impact

    The regulations adopted herein 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

[[Page 57513]]

levels of government. Therefore, it is determined that this final rule 
does not have federalism implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

2002-18-04 Boeing: Amendment 39-12878. Docket 2001-NM-34-AD.

    Applicability: Model 747-100, 747-100B, 747-100B SUD, 747-200B, 
747-300, 747SP, and 747SR series airplanes; line numbers 1 through 
810 inclusive; certificated in any category; and NOT equipped with a 
nose cargo door.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (e) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To find and fix cracking in certain upper deck floor beams, 
which could extend and sever floor beams adjacent to the body frame 
and result in rapid depressurization of the airplane, accomplish the 
following:

Inspections

    (a) At the compliance time specified in paragraph (a)(1) or 
(a)(2) of this AD, as applicable, perform one-time detailed and 
open-hole high frequency eddy current (HFEC) inspections for 
cracking in the upper deck floor beams at station (STA) 340 and STA 
360, according to Boeing Alert Service Bulletin 747-53A2459, dated 
January 11, 2001. For the purposes of this AD, flight cycles with a 
cabin differential pressure of 2.0 psi or less are not calculated 
into the compliance thresholds specified in this AD. However, all 
cabin pressure records must be maintained for each airplane, and no 
fleet averaging of cabin pressure is allowed.

    Note 2: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available lighting is normally 
supplemented with a direct source of good lighting at intensity 
deemed appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''

    (1) For airplanes with 22,000 or fewer total flight cycles as of 
the effective date of this AD: Do the inspections prior to the 
accumulation of 16,000 total flight cycles, or within 1,500 flight 
cycles after the effective date of this AD, whichever is later.
    (2) For airplanes with more than 22,000 total flight cycles as 
of the effective date of this AD: Do the inspections within 500 
flight cycles after the effective date of this AD.

Modification

    (b) If no crack is found during the inspections per paragraph 
(a) of this AD: Within 5,000 flight cycles after the initial 
inspections, modify the upper deck floor beams at STA 340 and STA 
360, according to Boeing Alert Service Bulletin 747-53A2459, dated 
January 11, 2001. If this modification is not accomplished before 
further flight after the inspections required by paragraph (a) of 
this AD, those inspections must be repeated one time, immediately 
before accomplishing the modification in this paragraph. If any 
crack is found during these repeat inspections, before further 
flight, accomplish paragraph (c)(2) of this AD.

Repair

    (c) If any crack is found during the inspections per paragraph 
(a) of this AD: Before further flight, repair according to either 
paragraph (c)(1) or (c)(2) of this AD.
    (1) Accomplish repairs according to paragraphs (c)(1)(i) and 
(c)(1)(ii) of this AD.
    (i) Accomplish a time-limited repair (including removing certain 
fasteners and the existing strap, performing open-hole HFEC 
inspections of the chord and web, stop-drilling web cracks, 
replacing the outboard section of the web, if applicable, and 
installing new straps) according to Boeing Alert Service Bulletin 
747-53A2459, dated January 11, 2001; except where the service 
bulletin specifies to contact Boeing for appropriate action, repair 
according to a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA; or according to data meeting the 
type certification basis of the airplane approved by a Boeing 
Company Designated Engineering Representative (DER) who has been 
authorized by the Manager, Seattle ACO, to make such findings. For a 
repair method to be approved as required by this paragraph, the 
approval must specifically reference this AD. AND
    (ii) Within 18 months or 1,500 flight cycles after installation 
of the time-limited repair according to paragraph (c)(1)(i) of this 
AD, whichever is first, do paragraph (c)(2) of this AD.
    (2) Accomplish a permanent repair according to Boeing Alert 
Service Bulletin 747-53A2459, dated January 11, 2001; except where 
the service bulletin specifies to contact Boeing for appropriate 
action, repair according to a method approved by the Manager, 
Seattle ACO; or according to data meeting the type certification 
basis of the airplane approved by a Boeing Company DER who has been 
authorized by the Manager, Seattle ACO, to make such findings. For a 
repair method to be approved as required by this paragraph, the 
approval must specifically reference this AD.

Repetitive Inspections: Post-Modification/Repair

    (d) Within 15,000 flight cycles after modification of the upper 
deck floor beams per paragraph (b) of this AD, or permanent repair 
of the upper deck floor beams per paragraph (c) of this AD, as 
applicable: Perform either open-hole HFEC inspections for cracking 
of fastener holes common to the upper chord, reinforcement straps, 
and the body frame; or surface HFEC inspections for cracking along 
the lower edge of the upper chord of the floor beam at the 
intersection with the body frame; and repeat these inspections at 
the interval specified in paragraph (d)(1) or (d)(2) of this AD, as 
applicable. Perform these inspections and repair any cracking found 
during these inspections according to a method approved by the 
Manager, Seattle ACO, or according to data meeting the type 
certification basis of the airplane approved by a Boeing Company DER 
who has been authorized by the Manager, Seattle ACO, to make such 
findings. For an inspection or repair method to be approved as 
required by this paragraph, the approval must specifically reference 
this AD.
    (1) If the most recent inspection used the surface HFEC method: 
Repeat the inspection within 1,000 flight cycles.
    (2) If the most recent inspection used the open-hole HFEC 
method: Repeat the inspection every 3,000 flight cycles.

    Note 3: There is no terminating action at this time for the 
repetitive post-modification/repair inspections according to 
paragraph (d) of this AD, and instructions for these inspections are 
not provided in Boeing Alert

[[Page 57514]]

Service Bulletin 747-53A2459, dated January 11, 2001.

Alternative Methods of Compliance

    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle ACO. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Seattle ACO.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (f) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

Incorporation by Reference

    (g) Except as provided by paragraphs (c)(1)(i), (c)(2), and (d) 
of this AD, the actions shall be done in accordance with Boeing 
Alert Service Bulletin 747-53A2459, dated January 11, 2001. This 
incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., Suite 700, Washington, DC.

Effective Date

    (h) This amendment becomes effective on October 16, 2002.

    Issued in Renton, Washington, on August 30, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-22855 Filed 9-10-02; 8:45 am]
BILLING CODE 4910-13-P