[Federal Register Volume 64, Number 227 (Friday, November 26, 1999)]
[Rules and Regulations]
[Pages 66361-66364]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30517]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-18-AD; Amendment 39-11430; AD 99-24-06]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -300, -400,
and -500 Series Airplanes; and Model 727-100 and -200 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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[[Page 66362]]
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 737-100, -200, -300, -400, and -500
series airplanes; and Model 727-100 and -200 series airplanes. This
amendment requires a one-time inspection to determine the presence and
condition of the breather plug in each fuel tank boost pump; and either
installation of a new plug or replacement of the boost pump with a new
or serviceable pump, if necessary. This amendment is prompted by a
report that breather plugs were missing from fuel tank boost pumps. The
actions specified by this AD are intended to prevent possible ignition
of fuel vapor in the fuel tank boost pump, which could result in a fuel
tank explosion in the event of a boost pump internal failure.
DATES: Effective January 3, 2000.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 3, 2000.
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: Dorr Anderson, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate,
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2684; 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 737-100, -
200, -300, -400, and -500 series airplanes; and all Model 727-100 and -
200 series airplanes; was published in the Federal Register on May 10,
1999 (64 FR 24964). That action proposed to require a one-time
inspection to determine the presence and condition of the breather plug
in each fuel tank boost pump; and either installation of a new plug or
replacement of the boost pump with a new pump, if necessary.
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.
Support for the Proposal
One commenter supports the proposed rule.
Request To Clarify Part Numbers of Affected Fuel Pump
Two commenters request that Argo-Tech/TRW fuel tank boost pumps
subject to the unsafe condition be identified by part number in the
proposed rule. The commenters state that there are Argo-Tech/TRW fuel
tank boost pumps with certain part numbers that are not subject to the
identified unsafe condition. The FAA concurs and has revised the
applicability section and paragraph (b) of the final rule accordingly.
Request To Allow Replacement With Serviceable Pumps
One commenter requests that the proposed rule be revised to allow
replacement of any discrepant fuel tank boost pump with a serviceable
pump. The proposed rule specifies that discrepant fuel tank boost pumps
be replaced with new pumps. The commenter states that boost pumps may
be overhauled and re-installed on airplanes. The FAA concurs with the
commenter that either overhauled or new pumps are acceptable for
compliance with this AD. Therefore, paragraph (a) of the final rule has
been revised to allow replacement of any discrepant boost pump with a
new or serviceable pump.
Request To Reference Additional Service Information
Three commenters request that the proposed rule be revised to
reference Boeing Alert Service Bulletin 737-28A1134, dated February 23,
1999, and Revision 1, dated June 10, 1999 (for Model 737 series
airplanes); and Boeing Alert Service Bulletin 727-28A0125, dated
February 23, 1999, and Revision 1, dated June 10, 1999 (for Model 727
series airplanes); as additional sources of service information. The
commenters state that these alert service bulletins provide
instructions equivalent to those contained in Boeing Telex M7200-98-
03173, dated October 21, 1998 (which is cited in the proposed rule as
the appropriate source of service information for accomplishment of the
inspection requirements of the proposed AD).
The FAA partially concurs and has revised paragraph (a) of the
final rule to cite Boeing Alert Service Bulletin 737-28A1134, Revision
1, and Boeing Alert Service Bulletin 727-28A0125, Revision 1, as
additional sources of service information. However, the original issues
of the alert service bulletins incorrectly identify the part numbers of
affected fuel tank boost pumps, though the procedures needed to
accomplish the required actions of this AD are correctly described.
Therefore, a note has been added to the final rule stating that, for
the applicable boost pumps, accomplishment of the actions in accordance
with the original issues of the alert service bulletins, prior to the
effective date of this AD, is acceptable.
Request for Change in Applicability
One commenter requests that the Model 737-500 series airplane be
excluded from the applicability of the proposed rule. The commenter
states that, to its knowledge, Argo-Tech/TRW fuel tank boost pumps
subject to the identified unsafe condition are not approved for
installation on the Model 737-500 series airplane. The commenter also
requests that boost pumps installed in the main or center fuel tanks of
the Model 737-400 series airplane be excluded from the applicability of
the proposed rule because, to its knowledge, Argo-Tech/TRW boost pumps
subject to the identified unsafe condition are not approved for
installation in those fuel tanks on the Model 737-400 series airplane.
The FAA does not concur. The FAA recognizes that Argo-Tech/TRW fuel
tank boost pumps subject to the identified unsafe condition were not
installed during production in any fuel tank on Model 737-500 series
airplanes or in the main or center fuel tanks of Model 737-400 series
airplanes. However, the FAA cannot confirm that these boost pumps were
not installed as part of a post-production modification to an airplane.
Therefore, the FAA continues to require that each operator confirm
whether Argo-Tech/TRW boost pumps subject to the identified unsafe
condition are installed on its airplanes. No change to the final rule
is necessary in this regard.
Request To Extend Compliance Time
One commenter requests that the proposal rule be revised to extend
the compliance time from the proposed 6 months to 12 months for the
inspection of the fuel tank boost pumps in the center fuel tanks on
Model 737 series airplanes and in the auxiliary fuel tanks on Model 737
and 727 series airplanes. The commenter requests this extension so that
affected operators will be able to perform the inspection during a
regularly scheduled maintenance interval. The commenter states that the
[[Page 66363]]
adoption of the proposed compliance time of 6 months would require
operators to schedule special times for the accomplishment of the
inspection, at additional expense and downtime.
The FAA does not concur. The operator provided no technical
justification for revising this interval as requested. The FAA
specifically selected a shorter compliance time for fuel tank boost
pumps in the center fuel tanks on Model 737 series airplanes and in the
auxiliary fuel tanks on Model 737 and 727 series airplanes because
these fuel tanks have a higher flammability exposure than the other
fuel tanks. This is due to the fact that these fuel tanks are warmer
than the main fuel tanks and because they are routinely operated until
they are dry, exposing the pump return lines directly to flammable fuel
vapors. The FAA considered not only those safety issues in developing
an appropriate compliance time for this action, but the recommendations
of the manufacturer, the availability of any necessary replacement
parts, and the practical aspect of accomplishing the required
inspection within an interval of time that parallels normal scheduled
maintenance for the majority of affected operators. In light of these
factors, the FAA has determined that the 6-month compliance time for
inspection of fuel tank boost pumps in the center fuel tanks on Model
737 series airplanes and in the auxiliary fuel tanks on Model 737 and
727 series airplanes, as proposed, is appropriate. No change to the
final rule is necessary in this regard.
Request To Reduce Compliance Time
One commenter requests that the proposed 6-month compliance time
for the inspection of fuel tank boost pumps in the center fuel tanks on
Model 737 series airplanes and in the auxiliary fuel tanks on Model 737
and 727 series airplanes be shortened to 3 months, and that the
proposed 12-month compliance time for the inspection of boost pumps in
the main fuel tanks on Model 737 series airplanes and in center and
main fuel tanks on Model 727 series airplanes be shortened to 6 months.
This commenter suggests that the proposed compliance time may be too
long to allow an airplane to fly with a potential failure that could
result in a fuel tank explosion. The commenter notes that the time
required to carry out the inspections will have minimal impact on
airplane operations.
The FAA does not concur with the request for a shorter compliance
time. In developing the proposed compliance time, the FAA considered
the probability of a fuel tank explosion occurring on any of these
airplanes due to a missing breather plug. The FAA determined that the
occurrence of a fuel tank ignition event is improbable; therefore, more
urgent action is not necessary. In making this determination, the FAA
has taken into account the conditions that are required for a missing
breather plug to cause a fuel tank explosion. Specifically, the FAA
considered the probability of an in-service fuel tank boost pump
missing a breather plug (based on inspections that had been conducted
on over 1,050 fuel pumps), the probability of a boost pump failure that
would cause an internal ignition inside the pump, and the probability
of fuel vapors in the fuel tank being flammable. The proposed
compliance times were determined to be appropriate in consideration of
the safety implications, the average utilization rate of the affected
fleet, the practical aspects of an orderly inspection of the fleet
during regular maintenance periods, and the availability of required
replacement parts. No change to the final rule is necessary in this
regard.
Request To Revise Compliance Time
One commenter requests that the proposed rule be revised to provide
an extension of the compliance time for any airplane that is out of
service for heavy maintenance for a long period of time. The commenter
suggests the compliance time should be within 6 months (or 12 months)
after the effective date of this AD, or prior to further flight,
whichever occurs later.
The FAA does not concur with the commenter's request; however, the
FAA agrees with the commenter's intent. Part 39 of the Federal Aviation
Regulations (14 CFR part 39) states that, ``No person may operate a
product to which an airworthiness directive applies except in
accordance with the requirements of that airworthiness directive.''
This regulation provides compliance relief for airplanes that are not
being operated, because affected airplanes need only be in compliance
prior to return to operation. No change to the final rule is necessary
in this regard.
Request for Credit for Previously Accomplished Actions
Two commenters request that a statement be added to the proposed
rule to clarify that no further action is required for airplanes that
have already accomplished the actions specified in the proposed rule.
The FAA agrees that no further action is required for these airplanes.
Operators are always given credit for previously accomplished actions
by means of the phrase in the compliance section of the AD that states,
``Required . . . unless accomplished previously.'' Therefore, no change
to the final rule is necessary in this regard.
Explanation of Change Made to Proposal
The airplane manufacturer has revised the instructions in the
airplane maintenance manual (AMM) sections specified in paragraph (a)
of the proposed rule to include, prior to installation of a new fuel
tank boost pump, a check of the vent port to ensure that a breather
plug is installed. The FAA finds that this check is appropriate.
Therefore, the FAA has revised paragraph (a) of the final rule to
specify that, after the effective date of the final rule, only Section
28-22-41 of the Boeing 737 AMM, dated May 1, 1999, or Section 28-22-21
of the Boeing 727 AMM, dated January 20, 1999, as applicable, shall be
used.
The FAA also has added a note to the final rule to clarify the
definition of a detailed visual inspection.
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 2,477 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 1,345 airplanes of U.S.
registry will be affected by this AD. It will take approximately 2 work
hours per fuel tank boost pump to accomplish the required actions at an
average labor rate of $60 per work hour. (There are 6 boost pumps in
the center and main fuel tanks on Model 737 series airplanes, 8 boost
pumps in the center and main fuel tanks on Model 727 series airplanes,
and 2 boost pumps in each auxiliary fuel tank, which may be installed
on some affected airplanes of both models.) Based on these figures, the
cost impact of the AD on U.S. operators is estimated to be $120 per
boost pump.
The cost impact figure discussed above is 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.
[[Page 66364]]
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
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:
99-24-06 Boeing: Amendment 39-11430. Docket 99-NM-18-AD.
Applicability: Model 737-100, -200, -300, -400, and -500 series
airplanes; and Model 727-100 and -200 series airplanes; certificated
in any category; equipped with Argo-Tech/TRW fuel tank boost pumps
having part numbers 258000-2, -3, and -5, or 382300-1, -2, and -3.
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 (c) 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 prevent possible ignition of fuel vapor in the fuel boost pump,
which could result in a fuel tank explosion, accomplish the following:
Inspection and Corrective Actions
(a) Perform a one-time detailed visual inspection to detect
discrepant breather plugs (including loose, damaged, and missing
plugs) in the fuel tank boost pumps, at the time specified in
paragraph (a)(1) or (a)(2), as applicable, of this AD; in accordance
with Boeing Telex M-7200-98-03173, dated October 21, 1998; or Boeing
Alert Service Bulletin 737-28A1134, Revision 1, dated June 10, 1999
(for Model 737 series airplanes); or Boeing Alert Service Bulletin
727-28A0125, Revision 1, dated June 10, 1999 (for Model 727 series
airplanes). If any discrepancy is detected, prior to further flight,
either install a new breather plug in accordance with Temporary
Revision (TR) No. 28-1 of the Argo-Tech Overhaul Manual, dated
November 13, 1998, or the alert service bulletins; or replace the
boost pump with a new or serviceable pump, in accordance with
procedures specified in Section 28-22-41 of the Boeing 737 Airplane
Maintenance Manual (AMM), or Section 28-22-21 of the Boeing 727 AMM,
as applicable. After the effective date of this AD, only Section 28-
22-41 of the Boeing 737 Airplane Maintenance Manual (AMM), dated May
1, 1999, or Section 28-22-21 of the Boeing 727 AMM, dated January
20, 1999, as applicable, shall be used for replacement of the boost
pump.
(1) For center fuel tanks installed on Model 737 series
airplanes, and for auxiliary fuel tanks installed on Model 727 and
737 series airplanes: Inspect within 6 months after the effective
date of this AD.
(2) For main fuel tanks installed on Model 737 series airplanes,
and for center and main fuel tanks installed on Model 727 series
airplanes: Inspect within 12 months after the effective date of this
AD.
Note 2: For the purposes of this AD, a detailed visual
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.''
Note 3: For Argo-Tech/TRW fuel tank boost pumps, part numbers
258000-2, -3, and -5, and 382300-1, -2, and -3: Accomplishment of
the actions specified in paragraph (a) of this AD, prior to the
effective date of this AD, in accordance with Boeing Alert Service
Bulletin 737-28A1134, dated February 23, 1999 (for Model 737 series
airplanes), or Boeing Alert Service Bulletin 727-28A0125, dated
February 23, 1999 (for Model 727 series airplanes), is acceptable
for compliance with this AD.
Spares
(b) As of the effective date of this AD, no person shall install
on any airplane an Argo-Tech/TRW fuel tank boost pump having the
part number 258000-2, -3, or -5; or 382300-1, -2, or -3; unless that
pump has been inspected and applicable corrective actions have been
performed in accordance with the requirements of this AD.
Alternative Methods of Compliance
(c) 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, Transport Airplane Directorate. 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
(d) 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
(e) The inspection and installation shall be done in accordance
with Boeing Telex M-7200-98-03173, dated October 21, 1998; Boeing
Alert Service Bulletin 737-28A1134, Revision 1, dated June 10, 1999;
Boeing Alert Service Bulletin 727-28A0125, Revision 1, dated June
10, 1999; or Temporary Revision No. 28-1 of the Argo-Tech Overhaul
Manual, dated November 13, 1998; as applicable. 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.
(f) This amendment becomes effective on January 3, 2000.
Issued in Renton, Washington, on November 17, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-30517 Filed 11-24-99; 8:45 am]
BILLING CODE 4910-13-P
