[Federal Register Volume 64, Number 169 (Wednesday, September 1, 1999)]
[Rules and Regulations]
[Pages 47656-47658]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22531]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-187-AD; Amendment 39-11283; AD 99-18-17]
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 adopts a new airworthiness directive (AD) that 
is applicable to all Boeing Model 737-100, -200, -300, -400, and -500 
series airplanes. This action requires repetitive replacements of the 
airplane battery with a new or reconditioned battery, and for certain 
airplanes, replacement of the battery charger with a new or serviceable 
battery charger. This action also requires performing repetitive tests 
to determine the condition of a certain diode of the Generator Control 
Units (GCU); and corrective actions, if necessary. This amendment is 
prompted by an incident during which all electrical power was lost due 
to a combination of a weak or depleted battery and the failure of a 
certain diode of the GCU. The actions specified in this AD are intended 
to prevent failure of all electrically powered airplane systems, which 
could result in the inability to continue safe flight and landing.

DATES: Effective September 16, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 16, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before November 1, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-187-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: Stephen S. Oshiro, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (425) 227-2793; fax (425) 
227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received a report of an incident 
during which all electrical power was lost due to a combination of a 
weak or depleted battery and the failure of a certain diode of the GCU 
on a Boeing Model 737-200 series airplane. The electrical configuration 
of a Boeing Model 737-200 series airplane is similar in design to that 
of Boeing Model 737-100, -300, -400, and -500 series airplanes. 
Therefore, Boeing Model 737-100, -300, -400, and -500 series airplanes 
maybe subject to the same unsafe condition revealed on the Model 737-
200 series airplane. The report revealed that, during an approach for 
landing, all electrical power was lost while the flight crew attempted 
a routine, in-flight start of the Auxiliary Power Unit (APU).
    Following from that incident, an assessment of airplane battery 
maintenance was conducted, which resulted in the determination that 
some operators have extended the maintenance intervals beyond those 
recommended by the manufacturer. Such extended maintenance intervals 
increase the likelihood of allowing an airplane to operate with a weak 
or depleted airplane battery. The risk of a weak or depleted battery is 
greater on Model 737-100 and -200 series airplanes than the Model 737-
300, -400 and -500 series airplanes because some of these airplanes 
utilize an older version of a battery charger. This older version of a 
battery charger has charging characteristics (overcharges and dries out 
the battery) that are not compatible with the extended airplane battery 
maintenance intervals. Additionally, certain diodes of the GCU have 
exhibited a susceptibility to short-circuit failure. The cause of these 
failures is under investigation.
    If an attempt is made to start the APU during flight with a weak or 
depleted battery, and a short-circuit failure of a certain diode of the 
GCU has occurred, all electrical power could be lost for all airplane 
systems. Such failure could result in the inability to continue safe 
flight and landing.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Telex Message M-7200-99-
01528, dated March 5, 1999, which describes procedures for performing 
repetitive tests to determine the condition of a certain diode of the 
GCU; and corrective actions, if necessary. The corrective actions 
include replacement of any GCU with a new or serviceable GCU if a 
failed diode is detected, and for certain conditions, replacement of 
the airplane battery with a new or reconditioned airplane battery.
    The FAA also has reviewed and approved Boeing 737 Airplane 
Maintenance Manual (AMM) Chapters 20-10-111 and 24-31-11. These service 
documents describe the following:
     AMM 20-10-111: For Model 737-100 and -200 series 
airplanes, this AMM describes procedures for removal and installation 
of black box units. For these airplane models, the airplane battery 
charger is considered to be a black box unit.
     AMM 24-31-11: For all Model 737-100, -200, -300, -400, and 
-500 series airplanes this AMM describes procedures for removal and 
installation of the airplane battery with a new or reconditioned 
airplane battery. Additionally, the AMM describes

[[Page 47657]]

procedures for cleaning and checking any installed airplane battery.

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 prevent failure of all electrically powered airplane 
systems, which could result in the inability to continue safe flight 
and landing. This AD requires accomplishment of the actions specified 
in the service documents described previously. This AD also requires 
that operators report results of inspection findings to the FAA.

Interim Action

    Since the cause of the failures of the GCU's is under 
investigation, this is considered to be interim action until final 
action is identified, at which time the FAA may consider further 
rulemaking.

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 99-NM-187-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:

99-18-17  Boeing: Amendment 39-11283. Docket 99-NM-187-AD.

    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 (f) 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 failure of all electrically powered airplane systems, 
which could result in the inability to continue safe flight and 
landing, accomplish the following:
    (a) For Model 737-100 and -200 series airplanes equipped with 
battery charger Boeing part number (P/N) 10-60701-1: Within 90 days 
after the effective date of this AD, accomplish the requirements of 
paragraphs (a)(1) and (a)(2) of this AD.
    (1) Replace the airplane battery charger with a new or 
serviceable airplane battery charger, Boeing P/N 10-60701-3, in 
accordance with Chapter 20-10-111 of the Boeing 737 Airplane 
Maintenance Manual (AMM); and
    (2) Replace the airplane battery with a new or reconditioned 
airplane battery in accordance with Chapter 24-31-11 of the Boeing 
737 AMM. Thereafter, replace the airplane battery with a new or 
reconditioned airplane battery at intervals not to exceed 750 flight 
hours.
    (b) For Model 737-300, -400, and -500 series airplanes: Within 
90 days after the effective date of this AD, replace the airplane 
battery with a new or reconditioned airplane battery in accordance 
with Chapter 24-31-11 of the Boeing 737 AMM. Thereafter, replace the 
airplane battery with a new or reconditioned airplane battery at 
intervals not to exceed 750 flight hours.
    (c) For all airplanes: Within 90 days after the effective date 
of this AD, perform a test to determine the condition of diode CR910 
of the Generator Control Units (GCU) in accordance with Boeing Telex 
Message M-7200-99-01528, dated March 5, 1999.

    Note 2: Any tests performed prior to the effective date of this 
AD, in accordance with Boeing Telex Message M-7200-99-01528, dated 
February 19, 1999, or dated March 4, 1999, are not considered 
acceptable for compliance with the applicable action specified by 
this AD.


[[Page 47658]]


    (1) If all diodes pass the test, repeat the diode test 
thereafter, at intervals not to exceed 600 flight hours.
    (2) If any diode fails the test: Prior to further flight, 
replace the GCU with a new or serviceable GCU, and if necessary, the 
airplane battery with new or reconditioned airplane battery, and 
repeat the diode test for the replaced GCU in accordance with the 
telex message until successful completion of the test is achieved. 
Repeat the diode test thereafter, at intervals not to exceed 600 
flight hours.
    (d) As of the effective date of this AD, no person shall install 
a battery charger having P/N 10-60701-1 on any Model 737 series 
airplane.
    (e) Within 10 days after accomplishing the initial diode test 
required by paragraph (c) of this AD, submit a report of the test 
results (negative findings) to the Manager, Seattle Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 227-
1181. 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.

Alternative Methods of Compliance

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

    Note 3: 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

    (g) 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

    (h) Except as provided by paragraphs (a) and (b) of this AD, the 
test shall be done in accordance with Boeing Telex Message M-7200-
99-01528, dated March 5, 1999. 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. 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.
    (i) This amendment becomes effective on September 16, 1999.

    Issued in Renton, Washington, on August 24, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-22531 Filed 8-31-99; 8:45 am]
BILLING CODE 4910-13-P