Airworthiness Directives; Boeing Model 737-600, -700, -700IGW, and -800 Series Airplanes

[Federal Register Volume 64, Number 23 (Thursday, February 4, 1999)]
[Rules and Regulations]
[Pages 5590-5592]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-2495]



[[Page 5590]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-362-AD; Amendment 39-11022; AD 99-03-08]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700IGW, 
and -800 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 737-600, -700, -700IGW, and -800 
series airplanes. This action requires repetitive inspections to detect 
discrepancies of the quick-disconnect coupling on the fuel hose, 
located at the fan case firewall; corrective action, if necessary; and 
installation of a clamp shell on the coupling to prevent separation of 
the coupling halves. This amendment is prompted by a report that a 
quick-disconnect coupling on the fuel hose on an in-service airplane 
was found loose and leaking fuel. The actions specified in this AD are 
intended to detect and correct excessive wear of the quick-disconnect 
coupling on the fuel hose, which could result in major fuel leakage, 
fire in the engine nacelle, and consequent loss of thrust from the 
affected engine.

DATES: Effective February 19, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 19, 1999.
     Comments for inclusion in the Rules Docket must be received on or 
before April 5, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-362-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: Bernie Gonzalez, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2682; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received a report indicating 
that the quick-disconnect coupling on the fuel hose was found loose and 
leaking fuel on an in-service Boeing Model 737-700 series airplane. As 
a result of this report, Boeing requested that all operators perform 
inspections to detect wear of the quick-disconnect coupling on the fuel 
hose on both engines of all Boeing Model 737-600, -700, -700IGW, and -
800 series airplanes. During these inspections, an excessively worn 
coupling was found on numerous airplanes, and several of these 
discrepant couplings were leaking fuel. Wear of the coupling, which is 
located at the fan case firewall of the engines, has been attributed to 
resonance vibration from the engine-driven hydraulic pump.
    Excessive wear of the quick-disconnect coupling on the fuel hose, 
if not corrected, could initially cause leakage of a small amount of 
fuel into the fan case fire zone of the engines. If such initial 
leakage is not detected and corrected, the coupling could become 
disconnected. Such disconnection could result in major fuel leakage, 
fire in the engine nacelle, and consequent loss of thrust from the 
affected engine.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-73A1011, dated November 25, 1998, which describes procedures for 
repetitive visual inspections to detect discrepancies (i.e., fuel 
leakage, wear of the lock teeth, and missing lock pins on the coupling 
nut) of the quick-disconnect coupling on the fuel hose; and corrective 
action, if necessary. If the coupling is found to be leaking, 
corrective actions include tightening the coupling nut; or if the 
coupling nut is tight, the lock teeth on the coupling are excessively 
worn, or one or more lock pins are missing, corrective actions include 
replacing the O-ring packing on the engine strut fuel fitting and 
replacing the fuel hose assembly. The alert service bulletin also 
describes procedures for installation of a clamp shell on the quick-
disconnect coupling to prevent separation of the coupling halves. 
Accomplishment of the actions specified in the alert service bulletin 
is intended to adequately address the identified unsafe condition.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to detect and correct excessive wear of the quick-
disconnect coupling on the fuel hose, located at the fan case firewall 
of the engines; which could result in major fuel leakage, fire in the 
engine nacelle, and consequent loss of thrust from the affected engine. 
This AD requires accomplishment of the actions specified in the alert 
service bulletin described previously, except as discussed below.

Differences Between This Rule and the Alert Service Bulletin

    Operators should note that this AD requires, within 30 days, the 
installation of the clamp shell described in the alert service 
bulletin. Installation of the clamp shell is identified in the alert 
service bulletin as an option that would allow the repetitive 
inspection interval to be increased from 500 to 1,000 flight hours.
    The FAA has determined that long-term continued operational safety 
will be better assured by installation of a device to prevent 
separation of the coupling halves and repetitive inspections at an 
interval not to exceed 1,000 flight hours, rather than by 
accomplishment of more frequent repetitive inspections (at intervals 
not to exceed 500 flight hours). Inspections alone (i.e., without the 
installation of the clamp shell) may not provide the degree of safety 
assurance necessary for the transport airplane fleet.
    In developing an appropriate compliance time for this AD, the FAA 
considered not only the manufacturer's recommendation, but the degree 
of urgency associated with addressing the subject unsafe condition, the 
availability of required parts, and the time necessary to perform the 
installation (2 work hours). In light of all of these factors, the FAA 
finds a compliance time of 30 days for accomplishing the installation 
to be warranted, in that it represents an appropriate interval of time 
allowable for affected airplanes to continue to operate without 
compromising safety.

Interim Action

    This is considered to be interim action. The manufacturer has 
advised that it currently is developing a modification that will 
positively address the unsafe condition addressed by this AD. Once this 
modification is developed, approved, and available, the FAA may 
consider additional rulemaking.

[[Page 5591]]

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-362-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 adding the following new 
airworthiness directive:

99-03-08  Boeing: Amendment 39-11022. Docket 98-NM-362-AD.

    Applicability: Model 737-600, -700, -700IGW, and -800 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 (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 detect and correct excessive wear of the quick-disconnect 
coupling on the fuel hose, which could result in major fuel leakage, 
fire in the engine nacelle, and consequent loss of thrust from the 
affected engine, accomplish the following:
    (a) Within 7 days after the effective date of this AD, perform a 
visual inspection to detect discrepancies (i.e., fuel leakage, wear 
of the lock teeth, or missing lock pins on the coupling nut) of the 
quick-disconnect coupling on the fuel hose, located at the fan case 
firewall, in accordance with Boeing Alert Service Bulletin 737-
73A1011, dated November 25, 1998.
    (1) If no discrepancy is detected, repeat the inspection 
thereafter at intervals not to exceed 500 flight hours, until the 
installation required by paragraph (b) of this AD is accomplished.
    (2) If any discrepancy is detected, prior to further flight, 
perform follow-on corrective actions, as applicable, in accordance 
with TABLE 1. of the Accomplishment Instructions of the alert 
service bulletin, and repeat the inspection thereafter at the time 
specified in TABLE 1. of the Accomplishment Instructions of the 
alert service bulletin.
    (b) Within 30 days after the effective date of this AD, install 
an Aeroquip Clamp Shell, having part number (P/N) AE20074-165, on 
the quick-disconnect coupling on the fuel hose, which is located at 
the fan case firewall, in accordance with Boeing Alert Service 
Bulletin 737-73A1011, dated November 25, 1998. Accomplishment of 
such installation terminates the repetitive inspection requirements 
of paragraph (a)(1) and (a)(2) of this AD. Within 1,000 flight hours 
after installation of the clamp shell, repeat the inspection 
specified in paragraph (a) of this AD.
    (1) If no discrepancy is detected, repeat the inspection 
thereafter at intervals not to exceed 1,000 flight hours.
    (2) If any discrepancy is detected, prior to further flight, 
perform follow-on corrective actions, as applicable, in accordance 
with TABLE 1. of the Accomplishment Instructions of the alert 
service bulletin, and repeat the inspection thereafter at the time 
specified in TABLE 1. of the Accomplishment Instructions of the 
alert service bulletin.
    (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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (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.
    (e) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 737-73A1011, dated November 25, 1998. This

[[Page 5592]]

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 February 19, 1999.

    Issued in Renton, Washington, on January 28, 1999.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-2495 Filed 2-3-99; 8:45 am]
BILLING CODE 4910-13-P

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