[Federal Register Volume 63, Number 189 (Wednesday, September 30, 1998)]
[Rules and Regulations]
[Pages 52152-52155]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-25971]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-254-AD; Amendment 39-10751; AD 98-19-09]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -300, -400, 
and -500 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to all Boeing Model 737-100, -200, -300, -400, and -
500 series airplanes, that currently requires removal of the fuel boost 
pump wiring in the conduits of the wing and center fuel tanks; an 
inspection to detect damage of the wiring, and corrective action, if 
necessary; and eventual installation of Teflon sleeving over the 
electrical cable. That AD was prompted by reports of severe wear of the 
fuel boost pump wiring due to chafing between the wiring and the 
surrounding conduit inside the fuel tank; pin-hole-sized holes in the 
conduit that appear to be the result of arc-through of the conduit; and 
exposure of the main tank boost pump wire conductor inside a conduit 
and signs of arcing to the wall of the conduit. This amendment expands 
the inspection requirement to include additional airplanes. The actions 
specified by this AD are intended to detect and correct chafing and 
electrical arcing between the fuel boost pump wiring and the 
surrounding conduit, which, if not corrected, could result in arc-
through of the conduit, and consequent fire or explosion of the fuel 
tank.

DATES: Effective October 15, 1998.
    The incorporation by reference of Boeing Alert Service Bulletin 
737-28A1120, dated April 24, 1998, as revised by Notices of Status 
Change NSC 01, dated May 7, 1998, NSC 02, dated May 8, 1998, and NSC 
03, dated May 9, 1998, as listed in the regulations, was previously 
approved by the Director of the Federal Register on June 29, 1998.
    The incorporation by reference of Boeing Alert Service Bulletin 
737-28A1120, Revision 1, dated May 28, 1998, as listed in the 
regulations, is approved by the Director of the Federal Register as of 
October 15, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before November 30, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-254-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    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 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.

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: On June 12, 1998, the FAA issued AD 98-11-
52, amendment 39-10611 (63 FR 34271, June 24, 1998), applicable to all 
Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, to 
require removal of the fuel boost pump wiring in the conduits of the 
wing and center fuel tanks; an inspection to detect damage of the 
wiring, and corrective action, if necessary; and eventual installation 
of Teflon sleeving over the electrical cable. That action was prompted 
by reports of severe wear of the fuel boost pump wiring due to chafing 
between the wiring and the surrounding conduit inside the fuel tank; 
pin-hole-sized holes in the conduit that appear to be the result of 
arc-through of the conduit; and exposure of the main tank boost pump 
wire conductor inside a conduit and signs of arcing to the wall of the 
conduit. The actions required by that AD are intended to detect and 
correct chafing and electrical arcing between the fuel boost pump 
wiring and the surrounding conduit, which, if not corrected, could 
result in arc-through of the conduit, and consequent fire or explosion 
of the fuel tank.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the FAA has received reports of 
severe chafing of the boost pump wiring (with wear of the primary wire 
insulation between 40 percent and 80 percent) on Boeing Model 737 
series airplanes that had accumulated between 29,000 and 35,000 total 
flight hours. Some of these airplanes had accumulated fewer flight 
hours than the number of flight hours specified as the inspection 
threshold in AD 98-11-52.
    In light of these findings, the FAA has determined that it is 
necessary to expand the inspection requirement to include airplanes 
that have accumulated between 20,000 and 30,000 total flight hours. 
This is necessary to ensure that these airplanes have not also 
developed a problem with chafing and electrical arcing between the fuel 
boost pump wiring and the surrounding conduit.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-28A1120, Revision 1, dated May 28, 1998. The procedures for 
inspecting the fuel boost pump wiring and installing Teflon sleeving 
are essentially identical to the procedures described in the original 
version of the alert service bulletin (referenced in AD 98-11-52). The 
only change effected by Revision 1 is to provide information concerning 
revised rework instructions and optional parts and procedures.

Explanation of Requirements of Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of this same type design, this AD 
supersedes AD 98-11-52 to continue to require removal of the fuel boost 
pump wiring in the conduits of the wing and center fuel tanks; an 
inspection to detect damage of the wiring, and corrective action, if 
necessary; and eventual installation of Teflon sleeving over the 
electrical cable. This AD expands the inspection requirement to include 
airplanes that have accumulated between 20,000 and 30,000 total flight 
hours. The actions are required to be accomplished in accordance with 
the alert service bulletin described previously. This AD also requires 
that operators report findings of discrepancies to the manufacturer.

Possible Future Rulemaking Action

    The FAA currently is considering further rulemaking action that 
would supersede this action to additionally require inspection of Model 
737 series airplanes that have accumulated less

[[Page 52153]]

than 20,000 total flight hours. However, the planned compliance time 
for the inspection is sufficiently long so that notice and opportunity 
for prior public comment will be practicable.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications shall identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-254-AD.'' The postcard will be date stamped and 
returned to the commenter.

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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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 removing amendment 39-10611 (63 FR 
34271, June 24, 1998), and by adding a new airworthiness directive 
(AD), amendment 39-10751, to read as follows:

98-19-09  Boeing: Amendment 39-10751. Docket 98-NM-254-AD. 
Supersedes AD 98-11-52, Amendment 39-10611.

    Applicability: All Model 737-100, -200, -300, -400, and -500 
series airplanes; certificated in any category.

    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 (m)(1) 
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 detect and correct chafing and electrical arcing between the 
fuel boost pump wiring and the surrounding conduit, which, if not 
corrected, could result in arc-through of the conduit, and 
consequent fire or explosion of the fuel tank, accomplish the 
following:

Inspections Required by AD 98-11-52

    (a) For all airplanes that have accumulated 50,000 or more total 
flight hours as of June 29, 1998 (the effective date of AD 98-11-52, 
amendment 39-10611): Prior to further flight, remove the fuel boost 
pump wiring from the in-tank conduit for the aft boost pumps in main 
tanks numbers 1 and 2, and perform a detailed visual inspection to 
detect damage of the wiring, in accordance with the procedures 
specified in Boeing Alert Service Bulletin 737-28A1120, dated April 
24, 1998, as revised by Notices of Status Change NSC 01, dated May 
7, 1998, NSC 02, dated May 8, 1998, and NSC 03, dated May 9, 1998; 
or Revision 1, dated May 28, 1998.
    (b) For all airplanes that have accumulated less than 50,000 
total flight hours as of receipt of telegraphic AD T98-11-51: Prior 
to the accumulation of 40,000 total flight hours, or within 14 days 
after June 29, 1998, whichever occurs later, remove the fuel boost 
pump wiring from the in-tank conduit for the aft boost pumps in main 
tanks numbers 1 and 2, and perform a detailed visual inspection to 
detect damage of the wiring, in accordance with the procedures 
specified in Boeing Alert Service Bulletin 737-28A1120, dated April 
24, 1998, as revised by Notices of Status Change NSC 01, dated May 
7, 1998, NSC 02, dated May 8, 1998, and NSC 03, dated May 9, 1998; 
or Revision 1, dated May 28, 1998.
    (c) For all airplanes: Remove the fuel boost pump wiring from 
the in-tank conduit for the center tank left and right boost pumps, 
and perform a detailed visual inspection to detect damage of the 
wiring, in accordance with the procedures specified in Boeing Alert 
Service Bulletin 737-28A1120, dated April 24, 1998, as revised by 
Notices of Status Change NSC 01, dated May 7, 1998, NSC 02, dated 
May 8, 1998, and NSC 03, dated May 9, 1998; or Revision 1, dated May 
28, 1998. Accomplish the inspection at the earliest of the times 
specified in paragraphs (c)(1), (c)(2), and (c)(3).
    (1) For Model 737-300, -400, and -500 series airplanes: Inspect 
prior to the accumulation of 40,000 total flight hours, or within 14 
days after June 29, 1998, whichever occurs later.
    (2) For Model 737-100 and -200 series airplanes: Inspect prior 
to the accumulation of 40,000 total flight hours, or within 10 days 
after June 29, 1998, whichever occurs later.
    (3) For all airplanes: Inspect prior to the accumulation of 
50,000 total flight hours, or within 5 days after June 29, 1998, 
whichever occurs later.
    (d) For all airplanes: Prior to the accumulation of 30,000 total 
flight hours or

[[Page 52154]]

within 45 days after June 29, 1998, whichever occurs later, remove 
the fuel boost pump wiring from the in-tank conduit for the aft 
boost pumps in main tanks numbers 1 and 2, and the center tank left 
and right boost pumps, and perform a detailed visual inspection to 
detect damage of the wiring, in accordance with the procedures 
specified in Boeing Alert Service Bulletin 737-28A1120, dated April 
24, 1998, as revised by Notices of Status Change NSC 01, dated May 
7, 1998, NSC 02, dated May 8, 1998, and NSC 03, dated May 9, 1998; 
or Revision 1, dated May 28, 1998.

New Inspection Requirement

    (e) For airplanes that have accumulated 20,000 or more total 
flight hours and less than 30,000 total flight hours as of the 
effective date of this AD: Within 60 days after the effective date 
of this AD, remove the fuel boost pump wiring from the in-tank 
conduit for the aft boost pumps in main tanks numbers 1 and 2, and 
the center tank left and right boost pumps, and perform a detailed 
visual inspection to detect damage of the wiring; in accordance with 
the procedures specified in Boeing Alert Service Bulletin 737-
28A1120, dated April 24, 1998, as revised by Notices of Status 
Change NSC 01, dated May 7, 1998, NSC 02, dated May 8, 1998, and NSC 
03, dated May 9, 1998; or Revision 1, dated May 28, 1998.

Corrective Actions

    (f) If red, yellow, blue, or green wire insulation cannot be 
seen through the outer jacket of the electrical cable during any 
inspection required by this AD: Prior to further flight, accomplish 
paragraph (f)(1), (f)(2), or (f)(3) of this AD in accordance with 
procedures specified in Boeing Alert Service Bulletin 737-28A1120, 
dated April 24, 1998, as revised by Notices of Status Change NSC 01, 
dated May 7, 1998, NSC 02, dated May 8, 1998, and NSC 03, dated May 
9, 1998; or Revision 1, dated May 28, 1998.
    (1) Install Teflon sleeving over the electrical cable, and 
reinstall the cable. Or
    (2) Reinstall the electrical cable without Teflon sleeving over 
the cable. Within 500 flight hours after accomplishment of the 
reinstallation, repeat the inspection described in paragraph (d) of 
this AD; and install Teflon sleeving over the cable. Or
    (3) Replace the electrical cable with new cable without Teflon 
sleeving. Within 18 months or 6,000 flight hours, whichever occurs 
first, repeat the inspection specified in paragraph (d) of this AD, 
and install Teflon sleeving over the cable.
    (g) If red, yellow, blue, or green wire insulation can be seen 
through the outer jacket of the electrical cable during any 
inspection required by this AD, but no evidence of electrical arcing 
is found: Prior to further flight, accomplish either paragraph 
(g)(1) or (g)(2) of this AD in accordance with the procedures 
specified in Boeing Alert Service Bulletin 737-28A1120, dated April 
24, 1998, as revised by Notices of Status Change NSC 01, dated May 
7, 1998, NSC 02, dated May 8, 1998, and NSC 03, dated May 9, 1998; 
or Revision 1, dated May 28, 1998.
    (1) Replace the damaged electrical cable with a new cable, 
install Teflon sleeving over the cable, and reinstall the cable. Or
    (2) Replace the electrical cable with a new cable without Teflon 
sleeving. Within 18 months or 6,000 flight hours, whichever occurs 
first, repeat the inspection described in paragraph (d) of this AD; 
and install Teflon sleeving over the cable.
    (h) If any evidence of electrical arcing but no evidence of fuel 
leakage is found on the removed electrical cable during any 
inspection required by this AD: Prior to further flight, accomplish 
paragraphs (h)(1) and (h)(2) of this AD in accordance with the 
procedures specified in Boeing Alert Service Bulletin 737-28A1120, 
dated April 24, 1998, as revised by Notices of Status Change NSC 01, 
dated May 7, 1998, NSC 02, dated May 8, 1998, and NSC 03, dated May 
9, 1998; or Revision 1, dated May 28, 1998.
    (1) Verify the integrity of the conduit in accordance with the 
instructions contained in NSC 03 or Revision 1 of the alert service 
bulletin. And
    (2) Accomplish either paragraph (h)(2)(i) or (h)(2)(ii) of this 
AD in accordance with the alert service bulletin.
    (i) Replace the damaged electrical cable with a new cable, 
install Teflon sleeving over the cable, and reinstall the cable. Or
    (ii) Replace the electrical cable with a new cable without 
Teflon sleeving. Within 18 months or 6,000 flight hours, whichever 
occurs first, repeat the inspection described in paragraph (d) of 
this AD; and install Teflon sleeving over the cable.
    (i) If any evidence of fuel is found on the removed electrical 
cable during any inspection required by this AD: Prior to further 
flight, accomplish paragraphs (i)(1) and (i)(2) of this AD in 
accordance with the procedures specified in Boeing Alert Service 
Bulletin 737-28A1120, dated April 24, 1998, as revised by Notices of 
Status Change NSC 01, dated May 7, 1998, NSC 02, dated May 8, 1998, 
and NSC 03, dated May 9, 1998; or Revision 1, dated May 28, 1998.
    (1) Replace the conduit section where electrical arcing was 
found. And
    (2) Accomplish either paragraph (i)(2)(i) or (i)(2)(ii) of this 
AD.
    (i) Replace the damaged electrical cable with a new cable, 
install Teflon sleeving over the cable, and reinstall the cable. Or
    (ii) Replace the electrical cable with a new cable without 
Teflon sleeving. Within 18 months or 6,000 flight hours, whichever 
occurs first, repeat the inspection described in paragraph (d) of 
this AD; and install Teflon sleeving over the cable.
    (j) For Groups 1 and 2 airplanes, as identified in Boeing Alert 
Service Bulletin 737-28A1120, dated April 24, 1998: Concurrent with 
the first accomplishment of corrective action in accordance with 
paragraph (f), (g), (h), or (i) of this AD, as applicable, replace 
the case ground wire with a new wire in accordance with Boeing Alert 
Service Bulletin 737-28A1120, dated April 24, 1998; as revised by 
Notices of Status Change NSC 01, dated May 7, 1998, NSC 02, dated 
May 8, 1998, and NSC 03, dated May 9, 1998; or Revision 1, dated May 
28, 1998.
    (k) Installation of Teflon sleeving over any electrical cable 
that is new or has been inspected in accordance with paragraph (a), 
(b), (c), (d), or (e) of this AD, constitutes terminating action for 
the requirements of this AD.
    (l) If any damage specified in paragraph (g), (h), or (i) of 
this AD is found during any inspection required by this AD, within 
10 days after accomplishing the inspection required by paragraph 
(a), (b), (c), (d), or (e) of this AD, as applicable, accomplish 
paragraphs (l)(1) and (l)(2) of this AD. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.
    (1) Submit any damaged electrical cables and conduits to Boeing, 
in accordance with Boeing Alert Service Bulletin 737-28A1120, dated 
April 24, 1998, as revised by Notices of Status Change NSC 01, dated 
May 7, 1998, NSC 02, dated May 8, 1998, and NSC 03, dated May 9, 
1998; or Revision 1, dated May 28, 1998; include the serial number 
of the airplane, the number of total flight hours and flight cycles 
accumulated on the airplane, and the location of the electrical 
cable on the airplane.
    (2) For airplanes that are inspected after June 29, 1998, submit 
the serial number of the airplane, the number of total flight hours 
and flight cycles accumulated on the airplane, and the location of 
the electrical cable on the airplane to the Manager, Seattle 
Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 
fax (425) 227-1181.
    (m)(1) 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.
    (m)(2) Alternative methods of compliance, approved previously in 
accordance with AD 98-11-52 are approved as alternative methods of 
compliance with this AD.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (n) Special flight permits may be issued in accordance with 
Secs. 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.
    (o) Except as provided in paragraph (k)(2) of this AD, the 
actions shall be done in accordance with Boeing Alert Service 
Bulletin 737-28A1120, dated April 24, 1998, as revised by Notice of 
Status Change NSC 01, dated May 7, 1998, Notice of Status Change NSC 
02, dated May 8, 1998, and Notice of Status Change NSC 03, dated May 
9, 1998; or Boeing Alert Service Bulletin 737-28A1120, Revision 1, 
dated May 28, 1998.
    (1) The incorporation by reference of Boeing Alert Service 
Bulletin 737-28A1120, Revision 1, dated May 28, 1998, as listed in 
the regulations, is approved by the Director of the Federal Register 
as of October 15, 1998.
    (2) The incorporation by reference of Boeing Alert Service 
Bulletin 737-28A1120,

[[Page 52155]]

dated April 24, 1998, as revised by Notice of Status Change NSC 01, 
dated May 7, 1998, Notice of Status Change NSC 02, dated May 8, 
1998, and Notice of Status Change NSC 03, dated May 9, 1998, was 
approved previously by the Director of the Federal Register as of 
June 29, 1998 (63 FR 34271, June 24, 1998).
    (3) 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.
    (p) This amendment becomes effective on October 15, 1998.

    Issued in Renton, Washington, on September 23, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-25971 Filed 9-29-98; 8:45 am]
BILLING CODE 4910-13-U