[Federal Register Volume 69, Number 96 (Tuesday, May 18, 2004)]
[Rules and Regulations]
[Pages 28046-28051]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-10906]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-297-AD; Amendment 39-13636; AD 2004-10-06]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727-100 and -200; 737-100, 
-200, -200C, -300, -400 and -500; and 747 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 727-100 and -200; 737-100, -200, -
200C, -300, -400 and -500; and 747 series airplanes. This amendment 
requires, among other things, preparation of the electrical bonding 
faying surfaces for the tubing penetrations of the hydraulic heat 
exchanger on the forward and aft surfaces of the rear spars of the fuel 
tanks of the left and right wings, a one-time measurement of the 
electrical bonding resistances, and follow-on actions. This action is 
necessary to ensure adequate electrical bonding between the penetration 
fittings of the hydraulic heat exchanger and the rear spars of the fuel 
tanks. Inadequate electrical bonding, in the event of a lightning 
strike, could cause electrical arcing and ignition of fuel vapor in the 
wing fuel tank, which could result in a fuel tank explosion. This 
action is

[[Page 28047]]

intended to address the identified unsafe condition.

DATES: Effective June 22, 2004.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 22, 2004.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplanes, PO 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 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.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6501; fax (425) 917-6590.

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 727-100 and -
200; 737-100, -200, -200C, -300, -400 and -500; and 747 series 
airplanes, was published in the Federal Register on July 21, 2003 (68 
FR 43040). That action proposed to require, among other things, 
preparation of the electrical bonding faying surfaces on the forward 
and aft surfaces of the rear spars of the fuel tanks of the left and 
right wings, a one-time measurement of the electrical bonding 
resistances, and follow-on actions.

Clarification of the Description of Electrical Bonding Faying Surfaces

    The FAA has clarified the description of the electrical bonding 
faying surfaces in the final rule. We have added ``for the tubing 
penetrations of the hydraulic heat exchanger'' after ``electrical 
bonding faying surfaces'' in the ``Summary'' paragraph of the preamble 
of the final rule and in paragraph (a) of the final rule.

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.

Request To Withdraw the Proposed AD

    Two commenters request to withdraw the proposed AD. The commenters 
point out that the unsafe condition addressed by the proposed AD is 
inadequate electrical bonding of the hydraulic heat exchangers to the 
rear spar, which could cause electrical arcing and subsequent ignition 
of fuel vapors in the wing fuel tank. The commenters note that Boeing 
Service Bulletin 737-29A1096, dated June 7, 2001, does not contain any 
reports where the non-bonded penetration fittings have resulted in 
arcing. The commenters believe this proposed AD for wing fuel tanks 
need not be mandated.
    We do not agree with the request to withdraw the proposed AD. 
Although there have been no reports where the non-bonded penetration 
fittings have resulted in arcing for the Model 737 series airplanes 
mentioned by the commenter, we find sufficient data exists to 
demonstrate that such potential remains. In addition, unless a fire or 
explosion results from an arcing event, there will not necessarily be 
evidence that such arcing occurred. Three catastrophic accidents have 
occurred when transport airplanes were struck by lightening: a Model 
707 series airplane at Elkton, Maryland, in 1963; a Boeing Model KC-135 
airplane in Spain in 1974; and a Model 747 series airplane in Madrid, 
Spain, in 1976. In one of those accidents, holes in metal debris from 
the accident pointed to a lightning strike that ignited fuel vapors 
inside a fuel tank. In the other two cases, observers from the ground 
confirmed that the airplanes had been struck by lightning and were in 
flames before crashing. These accidents have led us to require using 
conservative lightning safety design practices to preclude ignition 
sources in fuel tanks due to lightning. Laboratory lightning tests in 
conjunction with analyses conducted by the airplane manufacturer 
demonstrate the potential for in-tank arcing associated with a high 
electrical bonding resistance between the hydraulic heat exchangers and 
the airplane structure. Such high bonding resistances are expected to 
exist on these airplanes because of the details of the original design 
and production practices. In addition, lightning strikes are expected 
to occur several times in the life of each airplane. Data collected by 
the airplane manufacturer indicates that Model 737 and 747 series 
airplanes are struck by lightning approximately once per year. We and 
the airplane manufacturer are in agreement that a potential for arcing 
at the hydraulic line penetrations and at the heat exchanger exists in 
the event of a lightning strike to the engine or the wing for the 
Boeing Model 727, 737, and 747 series airplanes listed in Table 1 of 
the AD. We also considered the aging of the fleet of these Boeing 
airplanes in determining the severity of the unsafe condition. 
Therefore, we do not find it necessary to change the final rule in this 
regard.

Request To Extend Compliance Time

    Several commenters request that the proposed AD be revised to 
extend the compliance time specified in paragraph (a) of the proposed 
AD. One commenter suggests extending the compliance time for the 
initial actions from within 5 years (as proposed) to within 8 years or 
20,000 flight hours. Another commenter suggests extending the initial 
compliance time to within 6 years. That commenter also notes that there 
have not been any reported cases of arcing occurring at the heat 
exchanger to wing spar area on any of the affected fleet and some of 
the fleets have been in service over 40 years. Given those facts, that 
commenter believes an equivalent level of safety can be maintained over 
the 6-year compliance time. The commenters contend that extending the 
compliance time will allow affected operators to perform the inspection 
during a regularly scheduled maintenance interval while adoption of the 
proposed compliance time of within 5 years would require operators to 
schedule special times to do the inspection, at additional expense.
    We do not agree with the request to extend the compliance time 
specified in paragraph (a) of the final rule. The commenters provide no 
technical justification for revising the compliance time. The 
manufacturer has done a risk assessment analysis related to lightning 
strikes on the Model 727, 737, and 747 fleets and determined that an 
acceptable level of safety would be provided by a compliance time of 
five years for accomplishing the actions in the service bulletins 
(specified as the appropriate source of service information for the 
final rule). We concur with the manufacturer's assessment. We also 
considered the Air Transportation Association's (ATA's) guidelines of 
using an interval of five years for significant modifications when an 
acceptable level of safety is provided. Therefore, we have determined 
that the initial compliance time of within five years after the 
effective date of the AD, as specified in paragraph (a) of the final 
rule, is appropriate. We do not find it necessary to change the final 
rule in this regard. However, if operators care to provide technical 
justification, they may

[[Page 28048]]

request an approval of an alternative method of compliance (AMOC) from 
the FAA, in accordance with paragraph (e) of the final rule.

Request To Revise Compliance Time for Corrective Action for Incorrect 
Bonding Resistance

    Two commenters request that paragraph (a) of the proposed AD be 
revised by changing the compliance time to accomplish corrective action 
for any incorrect bonding resistances from ``Before further flight'' to 
``within 5 years after the effective date of this AD.'' The commenters 
are concerned that an inability to attain the specified electrical 
bonding resistances will delay return to service of the airplane which 
in turn could cause operational disruptions.
    We do not agree with the request to change the compliance time to 
accomplish corrective action for any incorrect bonding resistances. Our 
general policy is to require repair of known identified unsafe 
conditions before further flight (though we may make exceptions to this 
policy in certain cases of unusual need). Because of the safety 
implications and consequences associated with electrical resistances 
beyond a certain threshold, resistances below the threshold must be met 
before further flight. In addition, since the fuel tanks are open, 
there should be no undue burden to operators when they accomplish the 
corrective action for incorrect bonding resistances that is required by 
paragraph (a) of the final rule. We do not find it necessary to change 
the final rule in this regard.

Request To Revise Applicability for Boeing Model 747 Series Airplanes

    One commenter, the manufacturer, requests to revise the 
applicability in Table 1 of the proposed AD for Boeing Model 747 series 
airplanes. The manufacturer states that the effectivity listed for 
Boeing Alert Service Bulletin 747-29A2104, dated July 19, 2001, is 
``All 747 airplanes from line numbers 1 through 1271.'' The 
manufacturer points out that, at line number 1272, it incorporated a 
design change into Model 747 production that is equivalent to the 
change defined in the service bulletin. The manufacturer recommends 
changing the applicability for 747 series airplanes in Table 1 of the 
AD from ``as listed in Boeing Alert Service Bulletin 747-29A2104, dated 
July 19, 2001,'' to ``line numbers 1 thru 1271.''
    We agree that the applicability of the final rule should be revised 
for Boeing Model 747 series airplanes. For the reasons specified by the 
commenter, we have revised the ``Applicability'' for the 747 series 
airplanes in Table 1 of the final rule to ``Line Number 1 through 1271 
inclusive.'' The number of Model 747 series airplanes affected by the 
final rule has not changed.

Request To Allow Operator Equivalent Procedures for Draining and Access 
to the Fuel Tanks

    Two commenters request that operator equivalent procedures (OEPs) 
be allowed for draining and gaining access to the fuel tanks. The 
commenters contend that the wording in paragraph (a) of the proposed AD 
will prevent operators from using their own procedures for draining 
fuel tanks and preparing them for entry unless they request an AMOC. 
The commenters feel the intent of the proposed AD is to prepare and 
measure the electrical bond of the hydraulic heat exchangers and not to 
mandate how the fuel tanks are drained.
    We agree that OEPs may be allowed for draining and gaining access 
to the fuel tanks provided those procedures are FAA-accepted 
procedures. The use of OEPs for draining and gaining access to the fuel 
tank does not directly affect the means of correcting the unsafe 
condition. The use of OEPs may also reduce the costs of implementing 
the AD. Therefore, we have added paragraph (b) to the final rule 
stating: ``Operators may use their own FAA-accepted equivalent 
procedures for draining the fuel tanks and gaining access to the fuel 
tanks.'' We also revised paragraph (a) of the final rule by adding 
``except as provided by paragraph (b) of this AD'' and we revised the 
paragraph numbering following paragraph (b) of the final rule.

Request To Use Latest Revision of Boeing Alert Service Bulletin 737-
29A1096

    Several commenters request that Revision 1 of Boeing Alert Service 
Bulletin 737-29A1096, dated July 31, 2003, be referenced in the 
proposed AD instead of the original version of the service bulletin, 
dated June 7, 2001. The commenters point out that the manufacturer has 
issued Revision 1 of the service bulletin and it contains changes to 
the parts and procedures. The commenters also suggest that 
modifications accomplished per the original issue of the service 
bulletin be considered acceptable for compliance with the proposed AD.
    We agree with the commenters. We have reviewed and approved Boeing 
Alert Service Bulletin 737-29A1096, Revision 1, dated July 31, 2003, as 
the appropriate source of service information for the actions specified 
in the final rule. The changes in Revision 1 of the service bulletin 
clarify the parts and procedures described in the original version of 
the service bulletin. No additional work is specified in Revision 1 of 
the service bulletin. Accordingly, the final rule has been revised to 
reference Boeing Alert Service Bulletin 737-29A1096, Revision 1, dated 
July 31, 2003. In addition, paragraph (d) has been added to the final 
rule to allow actions accomplished before the effective date of the 
final rule per the original version of the service bulletin, dated June 
7, 2001, to be considered acceptable for compliance with the 
corresponding action specified in this final rule.

Request To Use Latest Revision of Boeing Alert Service Bulletin 747-
29A2104

    Two commenters request that Revision 1 of Boeing Alert Service 
Bulletin 747-29A2104, dated March 7, 2002, be referenced in the 
proposed AD instead of the original version of the service bulletin, 
dated July 19, 2001. The commenters point out that the proposed AD 
references the original version of the service bulletin and that 
Revision 1 of the service bulletin was issued on March 7, 2002.
    We agree with the commenters. We have reviewed and approved Boeing 
Service Bulletin 747-29A2104, Revision 1, dated March 7, 2002, as the 
appropriate source of service information for the actions specified in 
the final rule. The actions in Revision 1 of the service bulletin are 
almost identical to the actions described in the original version of 
the service bulletin. No additional work is specified in Revision 1 of 
the service bulletin. Accordingly, the final rule has been revised to 
reference Boeing Service Bulletin 747-29A2104, Revision 1, dated March 
7, 2002. In addition, the original version of the service bulletin, 
dated July 19, 2001, has been added to paragraph (d) of the final rule 
to allow actions accomplished before the effective date of the final 
rule per the original version of the service bulletin to be considered 
acceptable for compliance with the corresponding action specified in 
this final rule.

Request To Approve Future Revisions of Service Bulletins

    Two commenters request that approval be added for the 
accomplishment of future revisions of the service bulletins listed in 
Tables 1 and 2 of the proposed AD as being acceptable for compliance 
with the proposed AD. One commenter noted that there have been 
revisions to the

[[Page 28049]]

service bulletins listed in Tables 1 and 2 of the proposed AD.
    We do not agree with the request to approve accomplishment of 
future revisions of the service bulletins as being acceptable for 
compliance with the final rule. When referencing a specific service 
bulletin in a final rule, using a phrase such as, ``or later FAA-
approved revisions,'' violates Office of the Federal Register 
regulations for approving materials that are incorporated by reference. 
To allow operators to use later revisions of the referenced document 
(issued after publication of the final rule), either we must revise the 
final rule to reference specific later revisions, or operators must 
request approval to use later revisions as an AMOC with the final rule, 
under the provisions of paragraph (e) of the final rule. As stated 
previously, we have revised the final rule to specify the use of Boeing 
Alert Service Bulletin 737-29A1096, Revision 1, dated July 31, 2003; 
and Boeing Service Bulletin 747-29A2104, Revision 1, dated March 7, 
2002. We do not find it necessary to make any additional changes to the 
final rule in this regard.

Request To Remove Reference to Service Bulletin for Incorrect Bonding 
Resistance Corrective Action

    Two commenters request that paragraph (a) of the proposed AD be 
revised by removing the reference to Boeing Service Bulletin 737-
29A1096 listed in Table 2 for corrective action for any incorrect 
bonding resistance. One commenter notes that there are no specific 
corrective work instructions for incorrect electrical bonding 
resistances in the service bulletin.
    We agree that the reference for corrective action for any incorrect 
bonding resistances should be revised in paragraph (a) of the final 
rule. All the service bulletins listed in Table 2 of the final rule do 
not contain any instructions for correcting incorrect bonding 
resistances. We have revised the last sentence in paragraph (a) of the 
final rule to provide instructions for correcting incorrect bonding 
resistances as follows: ``If the bonding resistance is incorrect, 
before further flight, repeat the preparation of the electrical bonding 
faying surface on the forward and aft surfaces of the rear spar of the 
fuel tanks of the left and right wings as necessary to achieve a 
bonding resistance below the threshold specified in the Accomplishment 
Instructions of the applicable service bulletin listed in Table 2 of 
this AD.''

Request To Remove Reference to Service Bulletin for Leak Repairs

    Two commenters request that paragraph (b) of the proposed AD be 
revised by removing the reference to Boeing Alert Service Bulletin 737-
29A1096 for the repair of any leaks. One commenter notes that there are 
no leak repair instructions in the service bulletin. The commenter does 
agree that leakage should be repaired before further flight.
    We do not agree with the request to revise paragraph (c) of the 
final rule (specified in paragraph (b) of the proposed AD) by removing 
the reference to the service bulletin for repair of any leaks. While 
the service bulletin does not contain specific leak repair 
instructions, it does cite the appropriate airplane maintenance manuals 
for repair of any leaks. We do not find it necessary to change the 
final rule in this regard.

Request To Remove Identification of Rear Spar With Service Bulletin 
Number

    Two commenters request to remove the requirement to identify the 
rear spar with the service bulletin number as specified in Figure 8, 
Step 5, of Boeing Alert Service Bulletin 737-29A1096. One commenter 
believes there is no real benefit to this action and that it creates 
additional exterior markings that must be maintained. The commenter 
contends that tracking accomplishment of the service bulletin via 
aircraft records should be sufficient.
    We do not agree with the request to remove the requirement to 
identify the rear spar with the service bulletin number. The airplane 
manufacturer has studied this matter and concluded that the best method 
for identifying the accomplishment of the measurement and follow-on 
actions is to mark the service bulletin number on an appropriate 
airplane component. We concur with the manufacturer. We do not find it 
necessary to change the final rule 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.

Changes to 14 CFR part 39/Effect on the AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits, and alternative methods of 
compliance. However, for clarity and consistency in this final rule, we 
have retained the language of the NPRM regarding that material.

Change to Labor Rate Estimate

    We have 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 $60 per work 
hour to $65 per work hour. The cost impact information, below, reflects 
this increase in the specified hourly labor rate.

Cost Impact

    There are approximately 5,085 airplanes of the affected design in 
the worldwide fleet. We estimate that 2,251 airplanes of U.S. registry 
will be affected by this AD. The following table shows the estimated 
cost impact to do the required actions for airplanes affected by this 
AD. The average labor rate is $65 per work hour. The estimated maximum 
total cost for all airplanes affected by this AD is $6,827,860.

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                                                                      Number of U.S.-          Work hours         Labor cost        Maximum fleet cost
                              Model                                 registered airplanes      (estimated)        (estimated)           (estimated)
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727.............................................................                      910                 44             $2,860               $2,602,600
737.............................................................                    1,091                 44              2,860                3,120,260
747.............................................................                      250                 68              4,420                1,105,000
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    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

[[Page 28050]]

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 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

0
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

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. Section 39.13 is amended by adding the following new airworthiness 
directive:

2004-10-06 Boeing: Amendment 39-13636. Docket 2001-NM-297-AD.
    Applicability: This AD applies to the airplanes listed in Table 
1 of this AD, certificated in any category:

                         Table 1.--Applicability
------------------------------------------------------------------------
                  Model                            Applicability
------------------------------------------------------------------------
727-100 and -200 series airplanes........  As listed in Boeing Alert
                                            Service Bulletin 727-
                                            29A0067, dated June 7, 2001.
737-100, -200, -200C, -300, -400 and -500  As listed in Boeing Alert
 series airplanes.                          Service Bulletin 737-
                                            29A1096, Revision 1, dated
                                            July 31, 2003.
747 series airplanes.....................  Line Numbers 1 through 1271
                                            inclusive.
------------------------------------------------------------------------


    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 ensure adequate electrical bonding between the penetration 
fittings of the hydraulic heat exchanger and the rear spars of the 
fuel tanks of the left and right wings, accomplish the following:

Prepare Electrical Bonding Faying Surfaces/Measure Electrical Bonding

    (a) Within 60 months after the effective date of this AD: 
Prepare the electrical bonding faying surfaces for the tubing 
penetrations of the hydraulic heat exchanger on the forward and aft 
surfaces of the rear spars of the fuel tanks of the left and right 
wings, and do a one-time measurement of the electrical bonding 
resistances between the penetration fittings of the hydraulic heat 
exchanger and the rear spars, and between the heat exchanger tube 
and the lower wing stringer surfaces, per the Accomplishment 
Instructions of the applicable Boeing service bulletin listed in 
Table 2 of this AD, except as provided by paragraph (b) of this AD. 
The procedures include the following: Depressurize the hydraulic 
systems; drain the fuel from the fuel tanks; disconnect the inlet 
and outlet tubes of the heat exchangers and remove the heat 
exchangers; prepare the faying surface by sanding the surface areas 
down to bare metal and apply alodine protective coating on the 
surfaces, and re-install the heat exchangers. If the bonding 
resistance is incorrect, before further flight, repeat the 
preparation of the electrical bonding faying surface for the tubing 
penetrations of the hydraulic heat exchanger on the forward and aft 
surfaces of the rear spar of the fuel tanks of the left and right 
wings as necessary to achieve a bonding resistance below the 
threshold specified in the Accomplishment Instructions of the 
applicable service bulletin listed in Table 2 of this AD.

                                           Table 2.--Service Bulletins
----------------------------------------------------------------------------------------------------------------
              Model                Boeing service bulletin        Revision level                  Date
----------------------------------------------------------------------------------------------------------------
727-100 and -200.................              727-29A0067  Original.................  June 7, 2001.
737-100, -200, -200C, -300, -400               737-29A1096  Revision 1...............  July 31, 2003.
 and -500.
747..............................              747-29A2104  Revision 1...............  March 7, 2002
----------------------------------------------------------------------------------------------------------------

    (b) Operators may use their own FAA-accepted equivalent 
procedures for draining the fuel tanks and gaining access to the 
fuel tanks.

Follow-On Actions

    (c) Before further flight after accomplishment of paragraph (a) 
of this AD: Apply fillet sealant and protective finishes around the 
penetration fittings of the hydraulic heat exchanger per the 
Accomplishment Instructions of the applicable Boeing service 
bulletin listed in Table 2 of this AD (per Figure 4 of Boeing Alert 
Service Bulletin 727-29A0067; per Figure 8 of Boeing Alert Service 
Bulletin 737-29A1096, Revision 1; or per Figure 4 of Boeing Service 
Bulletin 747-29A2104, Revision 1; as applicable); then service and 
pressurize the hydraulic systems and examine for signs of hydraulic 
fluid leakage; and service the fuel tank and examine for signs of 
fuel leakage per the Accomplishment Instructions of the applicable 
service bulletin listed in Table 2 of this AD. Repair any leaks 
found before further flight, per the applicable service bulletin 
listed in Table 2 of this AD.

Actions Accomplished Per Previous Issue of Service Bulletin

    (d) Actions accomplished before the effective date of this AD 
per Boeing Alert Service Bulletin 737-29A1096, dated June 7, 2001; 
and Boeing Alert Service Bulletin 747-29A2104, dated July 19, 2001; 
as applicable, are considered acceptable for compliance with the 
corresponding action specified in this AD.

[[Page 28051]]

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 Aircraft Certification 
Office (ACO), FAA. 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (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) Unless otherwise specified in this AD, the actions shall be 
done in accordance with the applicable service bulletins listed in 
Table 3 of this AD:

                                     Table 3.--Applicable Service Bulletins
----------------------------------------------------------------------------------------------------------------
              Service bulletin                         Revision level                         Date
----------------------------------------------------------------------------------------------------------------
Boeing Alert Service Bulletin 727-29A0067..  Original.........................  June 7, 2001.
Boeing Alert Service Bulletin 737-29A1096..  Revision 1.......................  July 31, 2003.
Boeing Service Bulletin 747-29A2104........  Revision 1.......................  March 7, 2002.
----------------------------------------------------------------------------------------------------------------

    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 Airplanes, 
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 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.

Effective Date

    (h) This amendment becomes effective on June 22, 2004.


    Issued in Renton, Washington, on May 5, 2004.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-10906 Filed 5-17-04; 8:45 am]
BILLING CODE 4910-13-P